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CLARK AVENUE SUBDIVISION STORMWATER MNGT REPORT - PLANNING ,CiaR ►c aven�e� Suadiv �s►o;n, t \ ,� � l � � � � ,, �_,r �. NEW ENGLAND CIVIL ENGINEERING CORP. 120 WASHINGTON STREET,SUITE 202E,P.O.BOX 3026,SALEM,MA 01970 PH:978.741.7401-FAX:978.741.7402—WWW.ENGINEERINGCOMRATION.COM e March 9, 2016 Ms. Amanda Chiancola Staff Planner Office of Planning and Community Development 120 Washington Street Salem, MA 01970 Re: City of Salem RFQ 0-37—On-Call Civil Engineering Support Services, Task Order No. 34 (Amendment to Task Order 29) - Peer Review Services, Woodlands Subdivision (formerly Chapel Hill Estates), Salem, MA Dear Amanda: I greatly appreciated the opportunity to work with the Planning Board on a peer review for the above reference project. As discussed, we have prepared this Task Order letter amendment to increase the budget for this project. Proiect Understanding: We prepared a November 24, 2015 review letter and in response to a revised set of plans dated December 4, 2015 and a December 7, 2015 response letter, we prepared a second review letter dated December 30, 2015. SCOPE OF WORK: Task 1) Review existing City of Salem utility plans and information in the vicinity of the proposed Woodlands Subdivision on Clark Avenue and adjacent streets. Task 2) Review previous City of Salem development review letter(s)and Planning Board conditions of approval for previously approved project. Task 3)Attend meeting with City Engineer to discuss specific City concerns to be addressed in the peer review, including concerns and conditions from previous City Engineer review. Task 4) Review and compare/contrast previous development plans with current revised development plans, including building size and locations,parking and paved surface areas and configurations, grading and topography, and drainage infrastructure onsite as well as City of Salem infrastructure impacts. WATER RESOURCES - BURIED INFRASTRUCTURE-PUBLIC WORKS - CONSTRUCTION ADMINISTRATION - LAND DEVELOPMENT i Task 5) Complete site visit to observe the number and location of existing sewer and drainage structures, existing topography and impervious areas, and existing structures as shown on"Definitive Plan & Profile, Sheets 4 and 5, by Williams& Sparages Engineering. Task 6) Review Project Narrative and Environmental Impact Statement(not yet provided) and Stormwater Report prepared by Williams& Sparages Engineering. Task 7) Review site development plans prepared by Williams & Sparages Engineering. Review proposed on-site stormwater management system, pre and post-development runoff calculations, and stormwater quantity and quality issues. Review calculations for projected sanitary sewer flows, hydraulic calculations for proposed sanitary sewer design, and layout of proposed water and sanitary sewer piping. Task 8)Attend up to one (1) meeting with engineering representatives of Williams & Sparages Engineering to review the findings of the site walk and review of the documents summarized in Task 6. Task 9) Prepare Letter Report summarizing findings of the record search, site walk, document review, and meeting described in Tasks 1-8 above. Task 10) Attend up to one(1) meeting with Staff Planner and City Engineer to discuss findings of Letter Report. Task 11) Plan for and attend up to one (1) Planning Board public hearings to present findings of peer review. Expanded SCOPE OF WORK: Task 12) If requested by the City of Salem, provide additional engineering services as required to complete additional site visits, review additional project plans and documents beyond those described above, and attend additional meetings or public hearings. PROJECT BUDGET: Compensation for the Scope of work described in Task 1 through Task 11 shall be made based on periodic accrual invoices (time and materials), not to exceed the amount of One Thousand Six Hundred Dollars ($1,600.00)without written authorization from the City of Salem. Task 12 will be completed on an accrual (time and materials) basis at an hourly rate of$88.00 to$160.00. Written direction from the City of Salem will be required to expand scope of services. NEW ENGLAND CIVIL ENGINEERING CORP. Page 2 of 4 PROJECT SCHEDULE: New England Civil Engineering Corp. will complete the Scope of Services described in Task I through Task 1 above within 20 working days following receipt of written authorization to proceed and copies of all documents to be reviewed as described above. PAYMENT TERMS: Periodic invoices will be submitted to the Client and will be based on percentage completion of individual tasks as described above. Invoices are payable within fourteen (14)days of receipt and approval by Client. EXPENSES: The method for charging expenses, sub-contracted or supplemental services is 1.15 x the actual cost of the direct expense. ACCEPTANCE: This Task Ordered letter proposal, in conjunction with the reference Contract RFQ 0-37 issuance of Notice to Proceed dated June 3, 2013, will serve as an"Agreement to Professional Services". Please sign this proposal in the space provided and return one executed copy to my attention at your earliest convenience to initiate the project. We have provided five execution lines for City of Salem authorization to proceed but will be happy to revise or append the format of this letter with additional signature lines at your request. If you have any questions or require additional information, please do not hesitate to contact me at any time on my cell phone at 978-767-5415 or at my Salem office at 978-741-7401. We thank you for the opportunity to work with the City of Salem and look forward to building on our successful and rewarding partnership moving forward. Sincerely, i WilliamOP. . Project Manager/Principal Engineer New England Civil Engineering Corp. NEW ENGLAND CIVIL ENGINEERING CORP. Page 3 of 4 Task Order No. 34 Authorization: 14" >)-Nd Z Kimberley Driscoll Date: Mayo y n Duncan, AICP Date: Director of Planning and Community Development Sarah Stanton Date: Finance Director Whitney Haskell Date: Purchasing Agent Elizabeth Rennard Date: City Solicitor NEW ENGLAND CML ENGINEERING CORP. Page 4 of 4 I � y NEW ENGLAND CIVIL ENGINEERING CORP. 120 WASHINGTON STREET,SUITE 202E,P.O.BOX 3026,SALEM,MA 01970 PH:978.741.7401-FAX:978.741.7402—W W W.ENGINEERINGCORPORATION.COM t' J s December 30, 2015 Ms. Amanda Chiancola Staff Planner Office of Planning and Community Development 120 Washington Street Salem, MA 01970 Re: City of Salem RFQ 0-37—On-Call Civil Engineering Support Services, Task Order No. 29 - Peer Review Services, Woodlands Subdivision (formerly Chapel Hill Estates), Salem, MA Dear Amanda: We are pleased to support the Salem Planning Board with peer review services for the above referenced project. We understand the project is scheduled to be presented again at your upcoming January 7, 2015 meeting. We previously prepared a November 24, 2015 review letter and following our discussions with the Applicant's engineer they have submitted a December 7, 2015 response letter with a revised set of drawings dated December 4, 2015. We have prepared this project status letter for your consideration. Project Understanding: • NSD Realty Trust is proposing a development/redevelopment project on Clark Avenue . The project will involve construction of twenty seven (27) building lots, two (2) lots of open space, roadway buildings, parking lots, and related site work and utilities. • The project has been proposed for development/redevelopment in the past as "Chapel Hill Estates" and was approved but due to delay the approval expired. The plans and developer have both changed since previously approved project, requiring resubmission. • The City of Salem OCD will be reviewing the project for compliance with Salem Zoning Ordinance and Section 7-2 Cluster Residential Development and the Salem Subdivision Regulations. • The City of Salem requests an independent peer review of the proposed development plans and documentation including stormwater management, drainage, and on-site engineering issues covered by the Environmental Impact Statement including garbage, snow storage, etc.. • Included in the peer review will be consideration of existing and proposed utilities, sewer separation and infiltration issues. • Specific documents to be reviewed include a Cluster Residential Development and Subdivision Review Narrative (not yet reviewed, provided 11/24/15), Environmental Impact Statement, Stormwater Permit and Stormwater Report, and a set of Design Drawings (10 sheets). WATER RESOURCES - BURIED INFRASTRUCTURE-PUBLIC WORKS - CONSTRUCTION ADMINISTRATION - LAND DEVELOPMENT • We understand a notice of intent has been filed and wetland resource area provisions will be reviewed by the Conservation Commission and are not part of this review. • We understand the previous project was approved for this site with conditions that would require drainage improvements offsite on Clark Avenue and a capacity study of the sanitary sewer system tributary to the pumping station on Highland Avenue(near Walmart), including removal of all cost-effective, extraneous flows equal to, or greater than the proposed sewer flows from the Woodlands Subdivision development. We also understand there is a question about adequacy of fire flows. It is not clear at this time if this project will be subject to the same conditions and include the same improvements as the previous project, so a review of offsite utilities serving the project and adjacent areas are not included in the scope of this peer review. Review Comments: • Submittal Package o The Woodlands Subdivision design plans, 10 sheets (8/25/15) o Stormwater Report& Mitigative Drainage Analysis (08/31/15) o Cluster Residential Development and Subdivision Review Narrative (provided 11/24/15) o Environmental Impact Statement(provided 11/24/15) o Stormwater Management Permit (City of Salem, Planning Dept.) o Drainage Alteration Permit(City of Salem, Engineering Dept.) o Previous Design Plans, Chapel Hill Subdivision, 13 sheets (10/26/07) o City Engineer Memorandum (12/20/07) o Previous Planning Board Decision (03/03/08) Status=Ongoing, Stormwater Management Permit application, Drainage Alteration Permit application, Environmental Impact Statement, and Cluster Residential Development and Subdivision Review Narrative to be submitted for review. Site Development Plans • Lot 27, Utilities Sheet I of 10, Lot 27 It is not clear what future plans are for Lot 27 (148,000 so, as no drainage calculations or utility connections relating to this site are incorporated into this project. Status=Resolved - 12/7/15 Applicant Response Letter provides statement that there are no development plans for this lot. • Open Space and Access Sheets 1 and 6 of 10 o Similar to the Chapel Hill subdivision plans, 3+acres of open space is proposed on the north side of property and public access is provided to Open Space I in three locations with a constructed access trail. The Woodlands subdivision plans propose an additional 3+acres of open space on the south side of the property, but it is not clear how public will access Open Space 2. A single access location is provided around the back of Lot 27 and no access trail is proposed. NEW ENGLAND CIVIL ENGINEERING CORP. Page 2 of 7 Status=Ongoing discussion with Planning Board and Concom, revised 12/4/15 set of plans includes additional open space train in Open Space Lot 2,for review and approval by Planning Board. o Items 9, 11, 12 from previous decision require access to Open Space and trail construction, but restricts access trail construction to be completed without earthwork or machines, current proposed access trial involves removal of existing soils, and replacement with 3" minus stone (Sheet 5 of 10). Proposed construction is within the 100-foot buffer zone of resource area and downgradient of proposed erosion and sedimentation control barrier(Sheet 6 of 10). Status = Unresolved— 12/7/15 Applicant Response Letter suggests the issue of trail construction be discussed at Planning Board meeting. • Connection to Existing Utilities Sheets 4-7 of 10 o Connectivity of City of Salem water and sewer utilities on Clark Avenue and Clark Avenue Extension is not clear near points of proposed connection to the end of the cul-de-sac. o City typically requests triple gate valves at points of connection to City water mains. Status = Resolved, Applicant addressed in 12/7/15 Response Letter and 12/4/15 revised plans. o Items 13 and 14 from previous decision require improvements and/or studies to identify improvements to existing sewer and drainage utilities serving and in the vicinity of the project area, but information about proposed improvements is not included in the Status=Unresolved,Applicant working with City Engineer to finalize drainage and sewer improvements adjacent to and off site of proposed development. • Proposed Utilities Sheets 4-7 of 10 o Proposed water and sewer services are not shown on the plans, and should be included to demonstrate 10-foot separation. o Proposed water and sewer main layouts may need to be modified, to provide 10-foot separation in some areas, in particular in areas between large double catch basin structures. o City typically requires triple gate valve connections at intersections, no gate valves are proposed at South Ridge Circle intersection. o Items 16 and 22 from previous decision require sprinklers in accordance with NFPA 13D standards, plans should be revised to show separate fire service connections and valving to meet this standard and City standards. Status = Resolved,Applicant addressed in 12/7/15 Response Letter and 12/4/15 revised plans. • Proposed Topography and Detention Basins Sheets 4-7 of 10 NEW ENGLAND CML ENGINEERING CORP. Page 3 of 7 Spot grades along tops of forebay and basin embankments(high points between topographic contours) are referenced in report but not shown on plans, nor are forebay spillway elevations. Recommend additional elevations be added to plans to facilitate construction. Status = Resolved, Applicant addressed in 12/7/15 Response Letter and 12/4/15 revised plans. • Lighting Item 19 from previous decision describes street lighting requirements. A street lighting plan is not included in the design drawings. Status = Unresolved, Applicant provided a detail for proposed street lights in 12/4/15 plans, proposed locations of the street lights and conduits not yet provided. • hrigation Plan An irrigation plan is not provided on utility drawings, Applicant to confirm if irrigation is proposed and provide additional information about irrigation plan piping, connection to City water main, and backflow prevention and metering. Status = Resolved, Applicant states in 12/7/15 Response Letter that irrigation sprinklers are not proposed. • Snow Storage Plan for snow storage is not clear on plans if applicable. Status = Ongoing. Applicant has stated in 12/7/15 Response Letter that roadside snow storage is typical for residential streets. We have no solution to offer other than "haul out", but want to point out for discussion that snow storage at the end of cul-de-sacs may be problematic due to the likely obstruction of catch basins at each cul-de-sac and two driveways at one cul-de-sac. • Details Sheets 8, 9, and 10 of 10 o Item 17 from previous decision requires sidewalks with vertical granite curbs, and requires the sloped granite curb detail be removed from the plans. Plans do not clarify material for proposed sidewalks, City typically looks for concrete walks. Plans still include sloped granite curb detail which must be removed. o Typical fire hydrant detail appears to be missing water main line type on CAD. o Detail for proposed ADA ramp does not appear to allow for ramp alignment across intersections and along crosswalks. o Detail for rip rap embankment includes 4" perforated underdrain, location of underdrain piping is not shown on plans. o Foundation underdrain detail shown on Sheet 5, foundation underdrain piping is not shown ! on plans. Status = Resolved, Applicant addressed in 12/7/15 Response Letter and 12/4/15 revised plans. NEW ENGLAND CIVIL ENGINEERING CORP. Page 4 of 7 o Trail detail shown on Sheet 5 requires equipment and excavation, refer to previous comments about open space trails. Status = Unresolved— 12/7/15 Applicant Response Letter suggests the issue of trail construction be discussed at Planning Board meeting. o Numerous street trees (43) proposed along subdivision within grass strip. Grass strip appears to be approximately 2-feet wide between curb and sidewalk. Tree detail identifies root ball and size of excavation which do not appear to fit within grass strip. Recommend sidewalk layout be modified to 3 to 5-foot minimum width per City standards, and/or to include tree pits to facilitate trees. Status = Unresolved, Applicant to provide a list to Planning Board of trees suitable for planting in space available. Note: Page 8, paragraph 18 of Cluster Development Special Permit states trees will be minimum 3-1/2" caliper at breast height. o Cul-tec recharger detail provided on Sheet 9. Layout of recharger on Sheet 4 identifies a 4" outlet pipe at elevation 124.94'. The outlet pipe and piped discharge location is not identified on the detail or the layout. o A single, generic outlet control structure provided for reference without pipe sizes and elevations. Recommend specific details for outlet control structures be provided for each of the four basins for constructability. Status= Resolved,Applicant addressed in 12/7/15 Response Letter and 12/4/15 revised plans. Permits and Environmental Impact • Environmental Impact Statement Status = Unresolved, Applicant to provide permit application and narrative. • Drainage Alteration Permit(Engineering Dept.) Project includes a number of fill areas, including proposed cuts of approximately 20-feet and fills of approximately 16-feet. As a result, the project requires a drainage alteration permit from Salem Engineering Department. Status = Unresolved, Applicant to provide permit application and narrative. • Stormwater Management Permit(Planning Dept.) Status=Resolved. Cluster Development Special Permit • Page 9, paragraph 24,0., The drainage system for this project must be reviewed and approved by the Northeast Mosquito Control and Wetlands Management District. Status = Unresolved, Applicant to clarify conformance with this paragraph. NEW ENGLAND CIVIL ENGINEERING CORP. Page 5 of 7 I Stormwater and Drainage • Mitigative Drainage Analysis o Page 3, Catchment Mapping: Pre and Post development drainage catchment area delineation mapping was not provided for reference as part of the submittal package. Sheets 7 and 8 identify pre and post-contours and a single set of proposed flow arrows, but due to the extent of contour changes(20 foot cuts and 16 foot fills) it is difficult to visualize the changes to runoff patterns. It is also not clear if or how this project is influenced by runoff from adjacent property to the east. Status = Resolved, Applicant addressed in 12/7/15 Response Letter and 12/4/15 revised plans. • Mitigative Drainage Analysis o Page 1 of 20: Required and provided volumes are confusing between table provided on page 1, 2, 9, and 10. Request clarification or explanation of the information provided. o Page 7, Pond 1: volume table references elevation 131, plans appear to show bottom at 132'. Request clarification. o Page 9, Pond 1: storage depth listed at 0.75', plans appear to show 132.5'-132'=0.5'. o Page 9, Pond 2: storage depth listed at 0.50', plans appear to show 128.5'-128.5'=0'. o Page 10, Pond 4: storage depth listed at 1.0', plans appear to show 117.5%117=0.5' o Page 10, CultTec system: volume calculated as open void between 124.94' and 122.4', plans appear to show stone layer below 122.9' which may reduce volume. Status = Resolved,Applicant addressed in 12/7/15 Response Letter and 12/4/15 revised plans. • Emergency Overflow Page 4, Pond 1: It is not clear where emergency overflow from pond 1 spillway will flow, appears to be opposite direction of planned discharge. Status = Resolved,Applicant addressed in 12/7/15 Response Letter and 12/4/15 revised plans. • Long Term Pollution Prevention Plan o Page 1, Paragraph II states assumption that the City of Salem will assume full responsibility of continuing the operation and maintenance of the stormwater management system. Item 8 of previous decision states that a homeowner's association will have several responsibilities including maintenance of the stornwater management system which is in conflict. Status = Resolved, Applicant addressed in 12/7/15 Response Letter and 12/4/15 revised plans. Homeowners Association will be responsible for operations and maintenance. • Operations and Maintenance Plan o O&M Plan does not appear to include Sediment and Oil Separator. NEW ENGLAND CIVIL ENGINEERING CORP. Page 6 of 7 o O&M Plan does not appear to include sediment forebays and removal of sediment from forebays and detention basins if applicable. o Design of detention basins does not appear to provide vehicular access to the forebays and basins for maintenance, which are obstructed by walls or steep slopes in some places. o Maintenance of sub-surface infiltrators on page 2 requires the crushed stone and cul-tec chambers to be removed and replaced once sediment accumulates 3", which would represent a significant cost if required. Status =Resolved, Applicant addressed in 12/7/15 Response Letter and 12/4/15 revised plans. • Stormwater Checklist: Page 4 states Project is otherwise subject to Stormwater Standards only to the maximum extent practicable, Page 7 states that Standard 7 is not applicable which appears to be in conflict. Status =Resolved,Applicant addressed in 12/7/15 Response Letter and 12/4/15 revised plans. • Pre and Post Runoff- Standard 2 (Page 5) Pre and post runoff analysis provided for 2, 10, 100 year storm events and calculations predict that pre and post-development runoff rate requirements are met. Status =Previously Resolved. • Groundwater Recharge— Standard 3 (Pages], 2, 9, 10) Calculations predict recharge requirements met, however request clarification of required and provided recharge volume calculations in previous comments. Status= Resolved, Applicant addressed in 12/7/15 Response Letter and 12/4/15 revised plans. • Water Quality—Standard 4 TSS removal tables narrative details that pre-treatment is provided prior to infiltration BMPs and 80% TSS removal provided by BMP trains, (providing maintenance is performed). Status = Previously Resolved. If you have any questions or require additional information, please do not hesitate to contact me at any time on my cell phone at 978-767-5415 or at my Salem office at 978-741-7401. Sincerely, William M. Ross, P.E. Project Manager/Principal Engineer New England Civil Engineering Corp. Cc: David Knowlton, City Engineer Lynn Duncan, Amanda Chiancola, Salem Planning OCDP C lienWSalan/W oodlands/12302015leuer NEW ENGLAND CIVIL ENGINEERING CORP. Page 7 of 7 Project file: SAL1r0026 , & WILLIAMS 1 SPARAGES December 7, 2015 T Ms.Amanda Chiancola, Staff Planner (� Office of Planning and Community Development J 120 Washington Street Salem,MA 01970 RE: The Woodlands Subdivision, Salem, MA; NSD Realty Trust,Applicant Response to Peer Review Comments by New England Civil Engineering Corp. Dear Amanda, The purpose of this letter is to respond to comments received from New England Civil Engineering Corp. (NECE)as a result of their peer review of The Woodlands Subdivision plans in a letter dated November 24,2015 by Mr. William M. Ross.,P.E. The NECE comments are shown below in italics,and,the Williams&Sparages responses are in the bold text that follows. Site Development Plans • Lot 17, Utilities Sheet I of 10,.Lot 27 It is not clear what future plans are for Lot 27(148,000 sj), as no drainage calculations or utility connections relating to this site are incorporated into this project. Presently there are no development plans for this lot.Any proposed future development for Lot 27 would be required to comply with the criteria of all applicable permits for the City of Salem,including,but not limited to,engineering,zoning,site plan review,planning and conservation. • Open Space and Access Sheets I and 6 of 10 o Similar to the Chapel 1611 subdivision plans, 3+acres of open space is proposed on the north side ofproperty and public access is provided to Open Space 1 in three locations with a constructed access trail. The Woodlands subdivision plans propose an additional 3+acres of open space on the south side of the property, but it is not clear how public will access Open Space 2. A single access location is provided around the back of Lot 17 and no access trail is proposed. Based on discussions with the planning department and conservation commission we have added a walldng path within"Open Space 2"and lot 27. o Items 9, 11, 12 from previous decision require access to Open Space and trail construction, but restricts access trail construction to be completed without earthwork or machines, current proposed access trial involves removal of existing soils, and replacement with 3"minus stone(Sheet S of 10). Proposed construction is within the 189 North Main Street, Suite 101 • Middleton, MA 01949 • Tel: (978) 539-8988 • www.wsengineers.com Response to Peer Review by NECE The Woodlands Subdivision December 7,2015 100-foot buffer zone of resource area and downgradient of proposed erosion and sedimentation control barrier(Sheet 6 of 10). We suggest this item be discussed at the public hearing. • Connection to Existing Utilities Sheets 4-7 of 10 o Connectivity of City of Salem water and sewer utilities on Clark Avenue and Clark Avenue Extension is not clear near points of proposed connection to the end of the cul- de-sac. The sewer and water connections are shown on Profile Sheets 1 &2. The applicant proposes to run an eight(8") pvc sewer within the twenty-foot(20')wide easement for their benefit located on the adjacent land to the northwest owned Now or formerly(N/F) by Jeffrey M. & Ellen T.Rogato,Assessor's ID No.02-0046. o City typically requests triple gate valves at points of connection to City water mains. We have added two(2) additional water gates to the revised plans at the water main connection in Clark Avenue. o Items 13 and 14 from previous decision require improvements and/or studies to identify improvements to existing sewer and drainage utilities serving and in the vicinity of the project area, but information about proposed improvements is not included in the (sic) These items are currently the subject of discussion with the Planning Board. • Proposed Utilities Sheets 4-7 of 10 o Proposed water and sewer services are not shown on the plans, and should be included to demonstrate 10-foot separation. We have added the water& sewer service locations to the revised plans.Also,see note 8 on the Index Sheet which requires a ten(101)minimum separation as well as an eighteen-inch (18")vertical separation where the lines cross. o Proposed water and sewer main layouts may need to be modified, to provide 10 foot separation in some areas, in particular in areas between large double catch basin structures. On Woodlands Road,the only section where the horizontal separation is less than 10' from the water to the sewer is from centerline station 2+83 to station 3+52. However,in this location the vertical separation from the bottom of the water main(holding 5' of cover)to the top of the 8"PVC sewer pipe is greater than 18"and complies with note 8 as mentioned above. See revised profile which shows the section in question. 2 Response to Peer Review by NECE The Woodlands Subdivision December 7,2015 On South Ridge Circle,the only section where the horizontal separation is less than 10' from the water to the sewer is from centerline station 0+87 to station 0+94. However,in this location(at the sewer manhole)the vertical separation from the bottom of the water main to the top of the 8"PVC sewer pipe is greater than 18" and complies with note 8. See revised profile which shows the section in question. o City typically requires triple gate valve connections at intersections, no gate valves are proposed at South Ridge Circle intersection. We have added triple gates to the proposed water mains at the intersection of Woodlands Road and South Ridge Circle. o Items 16 and 22 from previous decision require sprinklers in accordance with NFPA 13D standards,plans should be revised to show separate fire service connections and valving to meet this standard and City standards. It is our understanding that the residential sprinklers will not require a separate fire service. • Proposed Topography and Detention Basins Sheets 4-7 of 10 Spot grades along tops offorebay,and basin embankments (high points between topographic contours)are referenced in report but not shown on plans, nor are forebay spillway elevations. Recommend additional elevations be added to plans to facilitate construction. We have added additional spot elevations,text and contour labels to the infiltration basins on the revised plans as recommended. • Lighting Item 19 from previous decision describes street lighting requirements. A street lighting plan is not included in the design drawings. Design to be provided by the service utility provider and/or towns fighting consultant.The prior approval document had specific language regarding the street fights.We would expect a similar condition for this project. • Irrigation Plan An irrigation plan is not provided on utility drawings, Applicant to confirm if irrigation is proposed and provide additional information about irrigation plan piping, connection to City water main, and backflow prevention and metering. No irrigation plan is proposed I I 3 Response to Peer Review by NECE The Woodlands Subdivision December 7,2015 • Snow Storage Plan for snow storage is not clear on plans if applicable. Snow storage to be at roadside as is typical for residential streets. • Details Sheets 8, 9, and 10 of 10 o Item 17 from previous decision requires sidewalks with vertical granite curbs, and requires the sloped granite curb detail be removed from the plans. Plans do not clarify material for proposed sidewalks, City typically looks for concrete walks. Plans still include sloped granite curb detail which must be removed. It is agreed that vertical granite will be used for the curbing. o Typical fire hydrant detail appears to be missing water main line type on CAD. See the revised detail which provides additional clarification on the size and type of water main. o Detail for proposed ADA ramp does not appear to allow for ramp alignment across intersections and along crosswalks. We have moved the ramps to be in fine with the direction of travel. o Detail for rip rap embankment includes 4"perforated underdrain, location of underdrain piping is not shown on plans. We have added teat to the detail that requires the 4"perforated PVC to discharge to "daylight"at intervals no greater than 30'. In the past,it has been our experience that this allows the installer flexibility in case an obstacle or other condition prevents the installation of the proposed underdrain where shown on the plans. o Foundation underdrain detail shown on Sheet 5,foundation underdrain piping is not shown on plans. This is a generic detail. Detailed locations will be provided on the designs for the individual lots. A note has been added prohibiting the discharge of the underdrains towards the sidewalk. o Trail detail shown on Sheet 5 requires equipment and excavation, refer to previous comments about open space trails. See response to previous comment above. 4 Response to Peer Review by NECE The Woodlands Subdivision December 7,2015 o Numerous street trees (43)proposed along subdivision within grass strip. Grass strip appears to be approximately 2-feet wide between curb and sidewalk. Tree detail identifies root ball and size of excavation which do not appear to f t within grass strip. Recommend sidewalk layout be modified to 3 to 5-foot minimum width per City standards, and/or to include tree pits to facilitate trees. The cross-section proposed is the standard cross-section. We will provide a list of street trees that are preferred. o Cul-tec recharger detail provided on Sheet 9. Layout of recharger on Sheet 4 identifies a 4"outlet pipe at elevation 124.94'. The outlet pipe and piped discharge location is not identified on the detail or the layout. The four(4")inch outlet pipe has been removed from the design since the time of the original submittal. See the revised plans. o A single, generic outlet control structure provided for reference without pipe sizes and elevations. Recommend specific details for outlet control structures be provided for each of the four basins for constructability. We have added specific details for each control structure for the four surface ponds. See sheet 11 of 11 on the revised plans. Permits and Environmental Impact • Environmental Impact Statement • Drainage Alteration Permit(Engineering Dept.) Project includes a number offU areas, includingproposed cuts ofapproximately 20- feet and f lls of approximately 16 feet. As a result, the project requires a drainage alteration permit from Salem Engineering Department. A drainage alteration permit will be requested from the engineering Department. • Stormwater Management Permit(Planning Dept) This permit has been applied for by the Applicant. Stormwater and Drainaee • Mitigative Drainage Analysis o Page 3, Catchment Mapping:Pre and Post development drainage catchment area delineation mapping was not provided for reference as part of the submittal package. Sheets 7 and 8 identify pre and post-contours and a single set of proposed flow arrows, but due to the extent ofcontour changes (20 foot cuts an 16 foot fills)it is difficult to visualize the changes to runoff patterns. It is also not clear if or how this project is influenced by run offfrom adjacent property to the east. 5 Response to Peer Review by NECE The Woodlands Subdivision December 7,2015 Existing&proposed condition watershed maps dated August 14, 2015 were placed in a pocket at the back of the original drainage report. The proposed condition watershed map has been revised since that time,see November 10,2015. There is some tributary area from the land to the east which is accounted for in the existing and proposed watershed calculations. Part of the area shown in Sub catchment EX-1 flows to the north and reaches the limit of the watershed analysis coincident with the edge of bordering vegetated wetlands. Two other Sub catchments,EX4 &EX-5, are both tributary to two separate isolated wetland areas as shown on the watershed maps which in the proposed condition falls within Lot 27. • Mitigative Drainage Analysis o Page I of 20:Required and provided volumes are confusing between table provided on page 1, 2, 9, and 10. Request clarification or explanation of the information provided. Page 1 breaks down the proposed impervious area into two types, i.e. roof or pavement. We then calculated the amount of required groundwater recharge volume based on hydrologic soil group"C",0.35 inches multiplied by the proposed impervious area of 121,471 sq.ft. The proposed water quality volume was then calculated by multiplying 0.5 inch(not in a critical area)times the amount of proposed pavement. The roof area is considered "Clean" by DEP and therefore is excluded from this calculation. The groundwater recharge volume calculated is greater than the water quality volume and therefore governs for the target amount of treatment volume that must be provided in the proposed infiltration basins. We then showed the amount of volume provided in the proposed infiltration basins equaling 6,094 cu.ft.which is greater than the amount of groundwater recharge volume required equaling 3,280 cu.ft. Page 2 is a check for the DEP compliance that the amount of impervious area captured by the proposed stormwater management system is at least 65%for the project. This project captures 86%of the impervious area and therefore meets this requirement. We then check to be certain that each infiltration basin is able to provide enough treatment volume based on the amount of impervious area tributary to it. As you can see from the table,each basin meets the requirement. The DEP Total Suspended Solids(TSS) removal requirement of 80%is met by the project which provides 85%,see spreadsheets. Pages 9& 10 show the minimum size of the infiltration area using DEP's"Simple Dynamic" method and how we are meeting the bottom of the system area requirement for each basin. 6 Response to Peer Review by NECE The Woodlands Subdivision December 7,2015 o Page 7, Pond]: volume table references elevation 131,plans appear to show bottom at 132'. Request clarification. Pages 7& 8 are the forebay sizing requirement calculations,therefore,the bottom elevations shown are for the forebays and not the bottom of the basin elevations. o Page 9, Pond 1: storage depth listed at 0.75 , plans appear to show 132.5'-132'=0.5'. The bottom of proposed Infiltration Basin 1 is elevation 132.0, the level eighteen inch (18") HDPE pipe and the four inch (4") diameter orifice in the control structure are both set at 132.75 which accounts for the 0.75' of storage provided. o Page 9, Pond 2: storage depth listed at 0.50', plans appear to show 128.5'-128.5'=0'. The bottom of proposed Infiltration Basin 2 is elevation 128.0, the level eighteen inch (18") HDPE pipe and the two and one-half inch (2.5") diameter orifice in the control structure are both set at 128.50 which accounts for the 0.5' of storage provided. o Page 10, Pond 4: storage depth listed at 1.0 , plans appear to show 117.5'-117=0.5' The bottom of proposed Infiltration Basin 4 is elevation 117.0, the level eighteen inch (18") HDPE pipe and the six inch (6") diameter orifice in the control structure are both set at 118.00 which accounts for the 1.0' of storage provided. o Page 10, Cultec system: volume calculated as open void between 124.94'and 122.4',plans appear to show stone layer below 122.9'which may reduce volume. This calculation is not for storage volume but for the area of the infiltration surface. Therefore,the volume provided in the stone is not in question,only depth to the outlet from the bottom of the system. As mentioned in the analysis,we have removed the outlet from the system and once it reaches capacity,runoff from the roadway will bypass the proposed catch basins at the entrance and will be intercepted by the existing catch basin on Clark Avenue Extension. Based on the surface area provided, 1,487 sq.ft.,this far exceeds the requirement shown equaling 86 sq.ft. shown in the equation. • Emergency Overflow Page 4, Pond 1: It is not clear where emergency overflow from pond I spillway will flow, appears to be opposite direction of planned discharge. The emergency overflow from Infiltration Basin 1,if used,would flow over the 8' long stone spillway then discharge along the northerly side of the proposed retaining wall at the rear boundary line of Lot 12 adjacent to land owned N/F by Tran 2014 Realty Trust and then onto Clark Avenue Extension. 7 Response to Peer Review by NECE The Woodlands Subdivision December 7,2015 • Long Term Pollution Prevention Plan o Page 1, Paragraph II states assumption that the City of Salem will assume full responsibility of continuing the operation and maintenance of the stormwater management system. Item 8 of previous decision states that a homeowner's association will have several responsibilities including maintenance of the stormwater management system which is in conflict. The Applicant is willing to accept a condition from the Planning Board that the responsibility of stormwater maintenance lies with the City of Salem or the Homeowner's Association .We will adjust the language in the documents. • Operations and Maintenance Plan o O&M Plan does not appear to include Sediment and Oil Separator. The Oil& Sediment Separator unit is included in the November 10,2015 revision. o O&M Plan does not appear to include sediment forebays and removal ofsediment from forebays and detention basins if applicable. See the November 10,2015 revision which outlines the procedure for debris removal from the Infiltration Basins which the sediment forebays are a part of. ' o Design ofdetention basins does not appear to provide vehicular access to the forebays and detention basins for maintenance, which are obstructed by walls or steep slopes in some places. See the areas labeled in the drainage easements which provide areas for access with maintenance equipment on the revised plans. o Maintenance of sub-surface infiltrators on page 2 requires the crushed stone and cul-tec chambers to be removed and replaced once sediment accumulates 3 which would represent a significant cost if required. This procedure would only be required if the crushed stone on the bottom of the system were to become completely clogged and no longer allowed the exfdtration of water. It is our experience with similar projects utilizing deep-sump catch basins and an oWsediment separator that there is enough pre-treatment to prevent this from happening. • Stormwater Checklist: Page 4 states Project is otherwise subject to Stormwater Standards only to the maximum extent practicable, Page 7 states that Standard 7 is not applicable which appears to be in conflict. This box is only checked as it relates to the DEP standard 3 for groundwater recharge for sites comprised solely of hydrologic soil group C and D soils and/or bedrock at the land surface and not for redevelopment which is standard 7. 8 Response to Peer Review by NECE The Woodlands Subdivision December 7,2015 • Pre and Post Runoff-Standard 2 (Page 5) Pre and post runoff analysis provided for 2, 10, 100 year storm events and calculations predict rates that pre and post-development runoff rate requirements are met. No response by Williams& Sparages required. • Groundwater Recharge—Standard 3 (Pages 1,2, 9, 10) Calculations predict recharge requirements met,however request clarification of required and provided recharge volume calculations in previous comments. See previous responses which provide the necessary clarification. • Water Quality—Standard 4 TSS removal tables narrative details that pre-treatment is provided prior to infiltration BMPs and 80%PSS removal provided by BMP trains, (providing maintenance is performed). No response by Williams& Sparages required. We trust that you will find the above responses to the peer review comments provided by NECE satisfactory. Should you have any additional questions,comments or concerns please do not hesitate to contact me by phone or email. Very Truly Yours, Richard L. Williams,P.E. Principal Cc: David Knowlton,City Engineer William M. Ross, P.E. NSD Realty Trust 9 NEW ENGLAND CIVIL ENGINEERING CORP. 120 WASHINGTON STREET,SUITE 202E,P.O.BOX 3026,SALEM,MA 01970 PH:978.741.7401-FAX:978.741.7402—W NW.ENGINEERINGCOPPORATION.COM t' J e - I November 24, 2015 Ms. Amanda Chiancola Staff Planner Office of Planning and Community Development 120 Washington Street Salem, MA 01970 i Re: City of Salem RFQ 0-37—On-Call Civil Engineering Support Services, Task Order No. 29 - Peer Review Services, Woodlands Subdivision (formerly Chapel Hill Estates), Salem, MA Dear Amanda: We are pleased to support the Salem Planning Board with peer review services for the above referenced project. We understand the project was scheduled to be presented at your upcoming December 3, 2015 meeting but has been continued and the discussion of utilities and stormwater will take place at a subsequent meeting. We have prepared this project status letter for your use in future meetings. Proiect Understanding: • NSD Realty Trust is proposing a development/redevelopment project on Clark Avenue . The project will involve construction of twenty seven (27) building lots, two (2) lots of open space, roadway buildings, parking lots, and related site work and utilities. • The project has been proposed for development/redevelopment in the past as"Chapel Hill Estates" and was approved but due to delay the approval expired. The plans and developer have both changed since previously approved project, requiring resubmission. • The City of Salem OCD will be reviewing the project for compliance with Salem Zoning Ordinance and Section 7-2 Cluster Residential Development and the Salem Subdivision Regulations. • The City of Salem requests an independent peer review of the proposed development plans and documentation including stormwater management, drainage, and on-site engineering issues covered by the Environmental Impact Statement including garbage, snow storage, etc.. • Included in the peer review will be consideration of existing and proposed utilities, sewer separation and infiltration issues. • Specific documents to be reviewed include a Cluster Residential Development and Subdivision Review Narrative(not yet reviewed, provided 11/24/15), Environmental Impact Statement(not yet reviewed; provided 11/24/15), Stormwater Permit and Stormwater Report(dated August 31, 2015), and a set of Design Drawings(10 sheets). i WATER RESOURCES - BURIED INFRASTRUCTURE-PUBLIC WORKS - CONSTRUCTION ADMINISTRATION - LAND DEVELOPMENT • We understand a notice of intent has not yet been filed and wetland resource area provisions will be reviewed by the Conservation Commission and are not part of this review. • We understand the previous project was approved for this site with conditions that would require drainage improvements offsite on Clark Avenue and a capacity study of the sanitary sewer system tributary to the pumping station on Highland Avenue (near Walmart), including removal of all cost-effective, extraneous flows equal to, or greater than the proposed sewer flows from the Woodlands Subdivision development. We also understand there is a question about adequacy of fire flows. It is not clear at this time if this project will be subject to the same conditions and include the same improvements as the previous project, so a review of offsite utilities serving the project and adjacent areas are not included in the scope of this peer review. Review Comments: • Submittal Package o The Woodlands Subdivision design plans, 10 sheets (8/25/15) o Stormwater Report & Mitigative Drainage Analysis (08/31/15) o Cluster Residential Development and Subdivision Review Narrative(Not yet provided) o Environmental Impact Statement (Not yet provided) o Stormwater Management Permit(City of Salem, Planning Dept.) o Drainage Alteration Permit (City of Salem, Engineering Dept.) o Previous Design Plans, Chapel Hill Subdivision, 13 sheets (10/26/07) o City Engineer Memorandum (12/20/07) o Previous Planning Board Decision (03/03/08) Status= Ongoing, Stormwater Management Permit application, Drainage Alteration Permit application, Environmental Impact Statement, and Cluster Residential Development and Subdivision Review Narrative to be submitted for review. Site Development Plans • Lot 27, Utilities Sheet I of 10, Lot 27 It is not clear what future plans are for Lot 27 (148,000 sf), as no drainage calculations or utility connections relating to this site are incorporated into this project. Status= Unresolved, Request Applicant clarify plans for this proposed Lot 27, as they relate to impacts on the proposed water, sewer, and drainage utilities in the development. • Open Space and Access Sheets I and 6 of 10 o Similar to the Chapel Hill subdivision plans, 3+ acres of open space is proposed on the north side of property and public access is provided to Open Space 1 in three locations with a constructed access trail. The Woodlands subdivision plans propose an additional 3+acres of open space on the south side of the property, but it is not clear how public will access Open Space 2. A single access location is provided around the back of Lot 27 and no access trail is proposed. NEW ENGLAND CIVIL ENGINEERING CORP. Page 2 of 7 o Items 9, 11, 12 from previous decision require access to Open Space and trail construction, but restricts access trail construction to be completed without earthwork or machines, current proposed access trial involves removal of existing soils, and replacement with 3" minus stone (Sheet 5 of 10). Proposed construction is within the 100-foot buffer zone of resource area and downgradient of proposed erosion and sedimentation control barrier(Sheet 6 of 10). Status=Unresolved, Request clarification if previous requirements are applicable to this project with respect to access to open space and construction of access trail, and recommend layout be confirmed with Conservation. • Connection to Existing Utilities Sheets 4-7 of 10 o Connectivity of City of Salem water and sewer utilities on Clark Avenue and Clark Avenue Extension is not clear near points of proposed connection to the end of the cul-de-sac. o City typically requests triple gate valves at points of connection to City water mains. o Items 13 and 14 from previous decision require improvements and/or studies to identify improvements to existing sewer and drainage utilities serving and in the vicinity of the project area, but information about proposed improvements is not included in the Status= Unresolved, Recommend Applicant revised proposed water connection to include triple gate valves and coordinate with City Engineering Department regarding capacity and improvements to the existing drain and sewer utilities. • Proposed Utilities Sheets 4-7 of 10 o Proposed water and sewer services are not shown on the plans, and should be included to demonstrate 10-foot separation. o Proposed water and sewer main layouts may need to be modified, to provide I0-foot separation in some areas, in particular in areas between large double catch basin structures. o City typically requires triple gate valve connections at intersections, no gate valves are proposed at South Ridge Circle intersection. o Items 16 and 22 from previous decision require sprinklers in accordance with NFPA 13D standards, plans should be revised to show separate fire service connections and valving to meet this standard and City standards. Status= Unresolved, Recommend Applicant revise plans to address proposed utility comments as appropriate. • Proposed Topography and Detention Basins Sheets 4-7 of 10 Spot grades along tops of forebay and basin embankments (high points between topographic contours) are referenced in report but not shown on plans, nor are forebay spillway elevations. Recommend additional elevations be added to plans to facilitate construction. Status=Ongoing, Recommend Applicant provide additional elevations to plans for constructability. NEIAT ENGLAND CIVIL ENGINEERING CORP. Page 3 of 7 i i • Lighting Item 19 from previous decision describes street lighting requirements. A street lighting plan is not included in the design drawings. Status=Unresolved, Request clarification if previous requirements are applicable to this project with respect to street lighting(and other miscellaneous issues in Items 15 and 16), and revise design plans to include street lighting and additional information as required. • Irrigation Plan An irrigation plan is not provided on utility drawings, Applicant to confirm if irrigation is proposed and provide additional information about irrigation plan piping, connection to City water main, and backflow prevention and metering. Status=Ongoing. Applicant to confirm and/or provide additional information. • Snow Storage Plan for snow storage is not clear on plans if applicable. Status=Ongoing. Applicant to confirm if snow storage is need and will be provided. • Details Sheets 8, 9, and 10 of 10 o Item 17 from previous decision requires sidewalks with vertical granite curbs, and requires the sloped granite curb detail be removed from the plans. Plans do not clarify material for proposed sidewalks, City typically looks for concrete walks. Plans still include sloped granite curb detail which must be removed. o Typical fire hydrant detail appears to be missing water main line type on CAD. o Detail for proposed ADA ramp does not appear to allow for ramp alignment across intersections and along crosswalks. o Detail for rip rap embankment includes 4 perforated underdrain, location of underdrain piping is not shown on plans. o Foundation underdrain detail shown on Sheet 5, foundation underdrain piping is not shown i on plans. o Trail detail shown on Sheet 5 requires equipment and excavation, refer to previous comments about open space trails. o Numerous street trees(43)proposed along subdivision within grass strip. Grass strip appears to be approximately 2-feet wide between curb and sidewalk. Tree detail identifies root ball and size of excavation which do not appear to fit within grass strip. Recommend sidewalk layout be modified to 3 to 5-foot minimum width per City standards, and/or to include tree pits to facilitate trees. o Cul-tec recharger detail provided on Sheet 9. Layout of recharger on Sheet 4 identifies a 4" outlet pipe at elevation 124.94'. The outlet pipe and piped discharge location is not identified on the detail or the layout. NEW ENGLAND CIVIL ENGINEERING CORP. Page 4 of 7 o A single, generic outlet control structure provided for reference without pipe sizes and elevations. Recommend specific details for outlet control structures be provided for each of the four basins for constructability. Status= Unresolved, Recommend Applicant revise plans to address construction detail comments as appropriate. Permits and Environmental Impact • Environmental Impact Statement Status=Unresolved, Applicant to provide permit application and narrative. • Drainage Alteration Permit(Engineering Dept.) Project includes a number of fill areas, including proposed cuts of approximately 20-feet and fills of approximately 16-feet. As a result, the project requires a drainage alteration permit from Salem Engineering Department. Status=Unresolved, Applicant to provide permit application and narrative. • Stormwater Management Permit(Planning Dept.) Status= Unresolved, Applicant to provide permit application and narrative for review. Stormwater and Drainage • Mitigative Drainage Analysis o Page 3, Catchment Mapping: Pre and Post development drainage catchment area delineation mapping was not provided for reference as part of the submittal package. Sheets 7 and 8 identify pre and post-contours and a single set of proposed flow arrows, but due to the extent of contour changes(20 foot cuts an 16 foot fills) it is difficult to visualize the changes to runoff patterns. It is also not clear if or how this project is influenced by runoff from adjacent property to the east. Status=Ongoing, Request Applicant provide pre and post-catchment delineation maps identifying the limits of all runoff entering or leaving the project area including adjacent land if applicable. • Mitigative Drainage Analysis o Page 1 of 20: Required and provided volumes are confusing between table provided on page 1, 2, 9, and 10. Request clarification or explanation of the information provided. o Page 7, Pond 1: volume table references elevation 131, plans appear to show bottom at 132'. Request clarification. o Page 9, Pond 1: storage depth listed at 0.75', plans appear to show 132.5'-132'=0.5'. o Page 9, Pond 2: storage depth listed at 0.50% plans appear to show 128.5'-128.5'=0'. o Page 10, Pond 4: storage depth listed at 1.0', plans appear to show 117.5'-I 17=0.5' o Page 10, CultTec system: volume calculated as open void between 124.94' and 122.4', plans appear to show stone layer below 122.9' which may reduce volume. NEW ENGLAND CIVIL ENGINEERING CORP. Page 5 of 7 Status= Unresolved, Request clarification on comments listed above and whether reduced volumes if applicable will impact the mitigative drainage analysis. • Emergency Overflow Page 4, Pond 1: It is not clear where emergency overflow from pond 1 spillway will flow, appears to be opposite direction of planned discharge. Status=Unresolved, Applicant to clarify. • Long Term Pollution Prevention Plan o Page I, Paragraph II states assumption that the City of Salem will assume full responsibility of continuing the operation and maintenance of the stormwater management system. Item 8 of previous decision states that a homeowner's association will have several responsibilities including maintenance of the stormwater management system which is in conflict. Status= Unresolved, Applicant to clarify who will be responsible for the operations and maintenance program for all the stromwater BMPs which is quite extensive. • Operations and Maintenance Plan o O&M Plan does not appear to include Sediment and Oil Separator. o O&M Plan does not appear to include sediment forebays and removal of sediment from forebays and detention basins if applicable. o Design of detention basins does not appear to provide vehicular access to the forebays and detention basins for maintenance, which are obstructed by walls or steep slopes in some places. o Maintenance of sub-surface infiltrators on page 2 requires the crushed stone and cul-tec chambers to be removed and replaced once sediment accumulates 3", which would represent a significant cost if required. Status=Ongoing, request clarification on 0&M plan for all BMPs, access to BMPs to facilitate maintenance, and responsible party for the operations and maintenance program for all the stromwater BMPs which is quite extensive. • Stormwater Checklist: Page 4 states Project is otherwise subject to Stormwater Standards only to the maximum extent practicable, Page 7 states that Standard 7 is not applicable which appears to be in conflict. Status=Ongoing, Applicant to clarify. • Pre and Post Runoff- Standard 2 (Page 5) Pre and post runoff analysis provided for 2, 10, 100 year storm events and calculations predict ates that pre and post-development runoff rate requirements are met. Status= Resolved. • Groundwater Recharge—Standard 3 (Pages 1, 2, 9, 10) NEW ENGLAND CML ENGINEERING CORP. Page 6 of 7 Calculations predict recharge requirements met, however request clarification of required and provided recharge volume calculations in previous comments. Status= Unresolved, pending response to previous comments. • Water Quality—Standard 4 TSS removal tables narrative details that pre-treatment is provided prior to infiltration BN/[Ps and 80%TSS removal provided by BMP trains, (providing maintenance is performed). Status= Resolved. If you have any questions or require additional information, please do not hesitate to contact me at any time on my cell phone at 978-767-5415 or at my Salem office at 978-741-7401. Sincerely, William M. Ross, P.E. Project Manager/Principal Engineer New England Civil Engineering Corp. Cc: David Knowlton, City Engineer Lynn Duncan, Amanda Chiancola, Salem Planning OCDP Climts/Salem/Woodlands/11242015letter NEW ENGLAND CIVIL ENGINEERING CORP. Page 7 of 7 PURCHASE ORDER Fiscal Year 2016 Page PLANNING DEPARTMENT Purchase 37-00 (978) 745-9595 EXT 5692 030041 Order # 120 WASHINGTON STREET 3RD FL SALEM, MA 01970 NEW ENGLAND CIVIL ENGINEERING CORP PLANNING DEPARTMENT P O BOX 3026 (978)745-9595 EXT 5692 120 WASHINGTON ST SUITE 202E 120 WASHINGTON STREET 3RD FL SALEM, MA 01970 SALEM, MA 01970 Vendor Phone Number Vendor Fax Number Requisition Number . Delivery Reference 978-741-7401 978-741-7402 00004530 Date Ordered Vendor Number .Date Required Freight Method/Terms'.' j- 7 Department/Location 11/09/15 015930 11/09/15 PLANNING Item# Description/Part No. Unit/Qty Cost Each Extended Price ORIGINAL 001 1.00 4800.00000 4,800.00 EACH STORM WATER PEER REVIEW, TASK ORDER #29 - CLARK AVENUE PO Total 4,800.00 ***** General Ledger Summary Section ***** Account Amount 24573-5713 4, 800.00 I CITY RECORDS INDICATE SUFFICIENT UNENCUMBERED FUNDS \ CITY OF SALEM ARE PRESENT IN THE BUDGET ACCOUNT. \\ e PURCHASING DEPARTMENT 120 Washington Street APPROVED BY SALEM, MASSACHUSETTS 01970 l / TEL(978) 745-9595 FAX (978) 744-5918 Whitney C. Haskell Purchasing Agent SALES TAX EXEMPTION #E-046-001-413 (NOT VALID WITHOUT CITY PURCHASING AGENT'S SIGNATURE) SERAFINI , DARLING & CORRENTI, LLP Mop ATTORNEYS AT LAW �(•` D S / 63 FEDERAL STREET CO SALEM. MASSACHUSETTS 01970 JOHN R. SERAFINI. SR. TELEPtZ JOHN E. DARLING 976-744-0212 JOSEPH C. CORRENTI FACSIMILE 978-741-4683 November 5, 2015 VIA HAND DELIVERY Amanda Chiancola, Staff Planner City of Salem Department of Planning and Community Development 120 Washington Street Salem, Massachusetts 01970 Re: NSD Realty Trust Application for Tentative Approval of Definitive Plan and Application for Cluster Residential Development Special Permit Application for Stormwater Management Clark Avenue and Clark Avenue Extension Assessor's Map 6, Parcels 7, 8 and 9 Dear Amanda: Enclosed please find check in the amount of $4,800.00, payable to the City of Salem, representing the civil engineering peer review fee in connection with the above project. If you require anything further, please do not hesitate to call me. JseVetruly yours, e ph C. Correnti Enclosures cc: client City of Salem Department of Planning & Community Development CHECK RECEIPT AND TRACKING FORM DATE / �2o�S BOARD1' IG n n► STAFF ' `V Y `a"& CLIENT: aH�RY1�� /1 Qe ,1 PROPERTY ADDRESS: ( IQKK Ve CONTACT NUMBER: q19- I y y . ZI 2 PURPOSE FOR f APPLICATION: 5hy-V0waw I n ec� CHECK # Ott AMOUNTRECEIVED: $ �1gOc� I 1 ' Project file: SALE-0026 WILLIAMS ' SPARAGES MNM . vuaxcas , wavtrou September 24, 2015 Salem Planning Board S ' 93 Washington Street Salem, MA 01970 ' RE: The Woodlands Subdivision, Salem, MA Stormwater Management permit Dear Dana, ' Please consider this letter an application for a Stormwater Management Permit pursuant to Chapter 37 of the City of Salem Code of ordinances. We are attaching the stormwater ' management report for the Woodlands residential subdivision project for your use and review. Please note that the report will also be submitted to the Salem Conservation Commission as part of the anticipated Notice of Intent filing. ' The report's contents support compliance with Salem's Stormwater Management Ordinance as well as the Massachusetts Stormwater Management Policy and associated ' regulations. The report provides specific detailed information regarding all necessary compliance with the policy, which is referenced as the standard in Chapter 37 . ' It is my understanding that this letter will allow the planning board to issue a Stormwatei Management permit as part of the ongoing permit modification process. ' Please feel free to let me know if you require further information or if you have any questions regarding this submittal. ' Very Truly Y urs, ' Richard L. Williams, P.E. Principal ' 189 North Main Street, Suite 101 • Middleton, MA 01949 • Tel: (978) 539-8088 0 www.wsengineers.com ' Project No. SALE-0026 Applicant: ' NSD Realty Trust 76 Oakville Street Lynn, MA 01905 1 Stormwater Report & 1 Mitigative Drainage Analysis for Proposed Cluster 1 Residential Subdivision 1 1 "The Woodlands'" (Clarke Avenue) Salem,. Massachusetts ' August 31, 2015 'W, & WILLIAMS 1 SPARAGES 1 S ' 189 North Main Street,Suite 101 Middleton,MA 01949 978-539-8088 Ph ' 978-539-8200 Fax www.wsengin�ers.com ' =��tH OF MgSs9oyG o PETER M. o BLAISDELL.JR, CIVIL N No.416130 �Q v Is STORMWATER REPORT TABLE OF CONTENTS Section 1. USGS Locus Map 2. Checklist for Stormwater Report 3. Long Term Pollution Prevention Plan (LTPPP) 4. Construction Period Pollution Prevention Plan.& Erosion and Sedimentation Control (CPPPP) 5. Mitigative DrainageAnalysis 6. Summary Tables 7. Existing Condition HydroCAD Analysis 8. Proposed Condition HydroCAD Analysis 9. Compliance Calculations Total Groundwater Recharge Required Percent Capture directed to Recharge I Water Quality Volume/TSS Removal TSS Removal Excel Spreadsheet Forebay sizing Simple Dynamic Method for sizing Recharge Drawdown Time Catch Basin Capacity Analysis Pipe Sizing Calculations ! ' 10. Soil Information 11. Operation & Maintenance Plan 12. Erosion & Sediment Control Plan 13. Snow disposal guidelines 14. Deicing Chemical (Road Salt) Storage 1 WILLIAMS& SPARAGES 189 NORTH CIVIL ENGINEERS, PLANNERS& , SUITE 101 LAND SURVEYORS MIDDLETON, PHONE: • :0: 0i RN As sl��t r r� 1,• '`S �i•� .��, . I � r�I���.���\�r �✓� MAIN -VA 0' FOA 3 M4 VM. INN NINN Pop GEOLOGICUNITED STATES 2015 LYNN QUADRANGLE "THE WOODLANDS"CLUSTER SUBDIVISION CONTINVERVAL=10'(NAVD 88) DANVERS,MASSACHUSETTS OUR (CLARK ' Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checklist for Stormwater Report ' A. Introduction Important:when A Stormwater Report must be submitted with the Notice of Intent permit application to document filling out forms compliance with the Stormwater Management Standards. The following checklist is NOT a substitute for Ion the computer, the Stormwater Report which should provide more substantive and detailed information but is offered use only the tab P ( P ) key to move your here as a tool to help the applicant organize their Stormwater Management documentation for their cursor-do not Report and for the reviewer to assess this information in a consistent format. As noted in the Checklist, Iuse the return the Stormwater Report must contain the engineering computations and supporting information set forth in key. Volume 3 of the Massachusetts Stormwater Handbook.The Stormwater Report must be prepared and . � certified by a Registered Professional Engineer(RPE) licensed in the Commonwealth. lw The Stormwater Report must include: • The Stormwater Checklist completed and stamped by a Registered Professional Engineer(see page 2)that certifies that the Stormwater Report contains all required submittals.' This Checklist is to be used as the cover for the completed Stormwater Report. Applicant/Project Name • Project Address ' • Name of Firm and Registered Professional Engineer that prepared the Report Long-Term Pollution Prevention Plan required by Standards 4-6 • Construction Period Pollution Prevention and Erosion and Sedimentation Control Plan required by Standard 82 • Operation and Maintenance Plan required by Standard 9 In addition to all plans and supporting information, the Stormwater Report must include a brief narrative describing stormwater management practices, including environmentally sensitive site design and LID techniques, along with a diagram depicting runoff through the proposed BMP treatment train. Plans are required to show existing and proposed conditions, identify all wetland resource areas, NRCS soil types, critical areas, Land Uses with Higher Potential Pollutant Loads(LUHPPL), and any areas on the site ' where infiltration rate is greater than 2.4 inches per hour. The Plans shall identify the drainage areas for both existing and proposed conditions at a scale that enables verification of supporting calculations. As noted in the Checklist, the Stormwater Management Report shall document compliance with each of the Stormwater Management Standards as provided in the Massachusetts Stormwater Handbook. The soils evaluation and calculations shall be done using the methodologies set forth in Volume 3 of the Massachusetts Stormwater Handbook. ' To ensure that the Stormwater Report is complete, applicants are required to fill in the Stormwater Report Checklist by checking the box to indicate that the specked information has been included in the t Stormwater Report. If any of the information specked in the checklist has not been submitted, the applicant must provide an explanation. The completed Stormwater Report Checklist and Certification must be submitted with the Stormwater Report. 'The Stormwater Report may also include the Illicit Discharge Compliance Statement required by Standard 10. If not included in the Stormwater Report,the Illicit Discharge Compliance Statement must be submitted prior to the discharge of stormwater runoff to the poslcoretruction best management practices. 2 For some complex projects,it may not be possible to include the Construction Period Erosion and Sedimentation Control Plan In the Stormwater Report. In that event,the issuing authority has the discretion to issue an Order of Conditions that approves the project and includes a condition requiring the proponent to submit the Construction Period Erosion and Sedimentation Control Plan before commencing any land disturbance activity on the site. swcheck.doc•04/01108 Stormwater Report Checklist•Page 1 of 8 ' Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checklist for Stormwater Report ' B. Stormwater Checklist and Certification The following checklist is intended to serve as a guide for applicants as to the elements that ordinarily need to be addressed in a complete Stormwater Report.The checklist is also intended to provide conservation commissions and other reviewing authorities with a summary of the components necessary for a comprehensive Stormwater Report that addresses the len Stormwater Standards. Note: Because stormwater requirements vary from project to project, it is possible that a complete Stormwater Report may not include information on some of the subjects specified in the Checklist. If it is determined that a specific item does not apply to the project under review, please note that the item is not applicable(N.A.)and provide the reasons for that determination. A complete checklist must include the Certification set forth below signed by the Registered Professional Engineer who prepared the Stormwater Report. Registered Professional Engineer's Certification I have reviewed the Stormwater Report, including the soil evaluation, computations, Long-term Pollution ' Prevention Plan, the Construction Period Erosion and Sedimentation Control Plan (if included), the Long- term Post-Construction Operation and Maintenance Plan, the Illicit Discharge Compliance Statement(if included)and the plans showing the stormwater management system, and have determined that they 1 have been prepared in accordance with the requirements of the Stormwater Management Standards as further elaborated by the Massachusetts Stormwater Handbook. I have also determined that the information presented in the Stormwater Checklist is accurate and that the information presented in the Stormwater Report accurately reflects conditions at the site as of the date of this permit application. �. Registered Professional Engineer Block and Signature NkOFMgSc _ 4y oma' PETER M. ' o BLAISDELL,JR. U CIVIL w No.0613a Q .o9O 9FGigTEPrc\��4, FFSSIONAL ' Signature and Date Checklist Project Type: Is the application for new development, redevelopment, or a mix of new and redevelopment? ® New development ❑ Redevelopment ❑ Mix of New Development and Redevelopment swcheck.doc•04/01/08 Stormwater Report Checklist•Page 2 of 8 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checklist for Stormwater Report ' Checklist (continued) LID Measures: Stormwater Standards require LID measures to be considered. Document what t environmentally sensitive design and LID Techniques were considered during the planning and design of the project: ® No disturbance to any Wetland Resource Areas ® Site Design Practices(e.g. clustered development, reduced frontage setbacks) ❑ Reduced Impervious Area (Redevelopment Only) ® Minimizing disturbance to existing trees and shrubs ' ❑ LID Site Design Credit Requested: ❑ Credit 1 ❑ Credit 2 ❑ Credit 3 ❑ Use of"country drainage'.versus curb and gutter conveyance and pipe ❑ Bioretention Cells(includes Rain Gardens) ❑ 'Constructed Stormwater Wetlands(includes Gravel Wetlands designs) ❑ Treebox Filter ' ❑ Water Quality Swale ® Grass Channel i ❑ Green Roof ❑ Other(describe): ' Standard 1: No New Untreated Discharges' i i ® No new untreated discharges ® Outlets have been designed so there is no erosion or scour to wetlands and waters of the Commonwealth ❑ Supporting calculations specked in Volume 3 of the Massachusetts Stormwater Handbook included. swcheck.doc•04/01/08 Stormwater Report Checklist•Page 3 of 8 ' Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checklist for Stormwater Report ' Checklist (continued) Standard 2: Peak Rate Attenuation ' ❑ Standard 2 waiver requested because the project is located in land subject to coastal storm flowage and stormwater discharge is to a wetland subject to coastal flooding. ® Evaluation provided to determine whether off-site flooding increases during the 100-year 24-hour storm. ® Calculations provided to show that post-development peak discharge rates do not exceed pre- development rates for the 2-year and 10-year 24-hour storms. If evaluation shows that off-site flooding increases during the 100-year 24-hour storm, calculations are also provided to show that post-development peak discharge rates do not exceed pre-development rates for the 100-year 24- hour storm. ' Standard 3: Recharge ❑ Soil Analysis provided. ' ® Required Recharge Volume calculation provided. ' ❑ Required Recharge volume reduced through use of the LID site Design Credits. ® Sizing the infiltration, BMPs is based on the following method: Check the method used. ' ❑ Static ® Simple Dynamic ❑ Dynamic Field' ❑ Runoff from all impervious areas at the site discharging to the infiltration BMP. ® Runoff from all impervious areas at the site is not discharging to the infiltration BMP and calculations are provided showing that the drainage area contributing runoff to the infiltration BMPs is sufficient to generate the required recharge volume. ® Recharge BMPs have been sized to infiltrate the Required Recharge Volume. ® Recharge BMPs have been sized to infiltrate the Required Recharge Volume only to the maximum extent practicable for the following reason: ® Site is comprised solely of C and D soils and/or bedrock at the land surface ❑ M.G.L. c. 21E sites pursuant to 310 CMR 40.0000 �' ❑ Solid Waste Landfill pursuant to 310 CMR 19.000 ® Project is otherwise subject to Stormwater Management Standards only to the maximum extent practicable. ❑ Calculations showing that the infiltration BMPs will drain in 72 hours are provided. I ❑ Property includes a M.G.L. c. 21 E site or a solid waste landfill and a mounding analysis is included. 80%TSS removal is required prior to discharge to Infiltration BMP if Dynamic Field method is used. swcheck.doc•04/01/08 Stormwater Report Checklist•Page 4 of 8 1 1 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checklist for Stormwater Report ' Checklist (continued) 1 Standard 3: Recharge (continued) ❑ The infiltration BMP is used to attenuate peak flows during storms greater than or equal to the 10- year 24-hour storm and separation to seasonal high groundwater is less than 4 feet and a mounding ' analysis is provided. ❑ Documentation is provided showing that infiltration BMPs do not adversely impact nearby wetland resource areas. ' Standard 4: Water Quality The Long-Term Pollution Prevention Plan typically includes the following: ' • Good housekeeping practices; • Provisions for storing materials and waste products inside or under cover; • Vehicle washing controls; ' • Requirements for routine inspections and maintenance of stormwater BMPs; • Spill prevention and response plans; Provisions for maintenance of lawns, gardens, and other landscaped areas; 1 • Requirements for storage and use.of fertilizers, herbicides, and pesticides; • Pet waste management provisions; • Provisions for operation and management of septic systems; • Provisions for solid waste management; • Snow disposal and plowing plans relative to Wetland Resource Areas; • Winter Road Salt and/or Sand Use and Storage restrictions; • Street sweeping schedules; • Provisions for prevention of illicit discharges to the stormwater management system; • Documentation that Stormwater BMPs are designed to provide for shutdown and containment in the event of a spill or discharges to or near critical areas or from LUHPPL; ' • Training for staff or personnel involved with implementing Long-Term Pollution Prevention Plan; • List of Emergency contacts for implementing Long-Term Pollution Prevention Plan. ® A Long-Term Pollution Prevention Plan is attached to Stormwater Report and is included as an. attachment to the Wetlands Notice of Intent. ❑ Treatment BMPs subject to the.44%TSS removal pretreatment requirement and the one inch rule for calculating the water quality volume are included, and discharge: ❑ is within the Zone II or Interim Wellhead Protection Area ❑ is near or to other critical areas ❑ is within soils with a rapid infiltration rate(greater than 2.4 inches per hour) ❑ involves runoff from land uses with higher potential pollutant loads. ❑ The Required Water Quality Volume is reduced through use of the LID site Design Credits. ' ® Calculations documenting that the treatment train meets the 80%TSS removal requirement and, if applicable, the 44%TSS removal pretreatment requirement, are provided. swcheck.doc•04/01/08 Stormwater Report Cheddist•Page 5 of 8 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checklist for Stormwater Report ' Checklist (continued) ' Standard 4: Water Quality(continued) ® The BMP is sized (and calculations provided) based on: Th %" r 1°Water Quality Volume or ❑ The equivalent flow rate associated with the Water Quality Volume and documentation is provided showing that the BMP treats the required water quality volume. ❑ The applicant proposes to use proprietary BMPs, and documentation supporting use of proprietary BMP and proposed TSS removal rate is provided. This documentation may be in the form of the propriety BMP checklist found in Volume 2, Chapter 4 of the Massachusetts Stormwater Handbook and submitting copies of the TARP Report, STEP Report, and/or other third party studies verifying performance of the proprietary BMPs. ❑ A TMDL exists that indicates a need to reduce pollutants other than TSS and documentation showing ' that the BMPs selected are consistent with the TMDL is provided. Standard 5: Land Uses With Higher Potential Pollutant Loads(LUHPPLs) N El The NPDES Multisector General Permit covers the land use and the Stormwater Pollution Prevention Plan(SWPPP)has been included with the Stormwater Report. ❑ The NPDES Multi-Sector General Permit covers the land use and the SWPPP will be submitted prior to the discharge of stormwater to the post-construction stormwater BMPs. ❑ The NPDES Multi-Sector General Permit does not cover the land use. ' ❑ LUHPPLs are located at the site and industry speck source control and pollution prevention measures have been proposed to reduce or eliminate the exposure of LUHPPLs to rain, snow, snow melt and runoff, and been included in the longterm Pollution Prevention Plan. I ❑ All exposure has been eliminated. ❑ All exposure has not been eliminated and all BMPs selected are on MassDEP LUHPPL list. ❑ The LUHPPL has the potential to generate runoff with moderate to higher concentrations of oil and grease(e.g. all parking lots with >1000 vehicle trips per day)and the treatment train includes an oil ' grit separator, a filtering bioretention area, a sand filter or equivalent. Standard 6: Critical Areas ' 1J,(k. ❑ The discharge is near or to a critical area and the treatment train includes only BMPs that MassDEP ((( has approved for stormwater discharges to or near that particular class of critical area. ❑ Critical areas and BMPs are identified in the Stormwater Report. � t swcheck.doc•04/01/08 Stormwater Report Checklist•Page 6 of 8 1 ' Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checklist for. Stormwater Report Checklist (continued) Standard 7: Redevelopments and Other Projects Subject to the Standards only to the maximum extent practicable ❑ The project is subject to the Stormwater Management Standards only to the maximum Extent Practicable as a: ❑ Limited Project ❑ Small Residential Projects: 5-9 single family houses or 5-9 units in a multi-family development provided there is no discharge that may potentially affect a critical area. ❑ Small Residential Projects: 2-4 single family houses or 2-4 units in a multi-family development with a discharge to a critical area ❑ Marina and/or boatyard provided the hull painting, service and maintenance areas are protected ' from exposure to rain, snow, snow melt and runoff ❑ Bike Path and/or Foot Path 1 ❑ Redevelopment Project El Redevelopment portion of mix of new and redevelopment. ❑ Certain standards are not fully met(Standard No. 1, 8, 9, and 10 must always be fully met)and an explanation of why these standards are not met is contained in the Stormwater Report. ❑ The project involves redevelopment and a description of all measures that have been taken to improve existing conditions is provided in the Stormwater Report. The redevelopment checklist found in Volume 2 Chapter 3 of the Massachusetts Stormwater Handbook may be used to document that the proposed stormwater management system (a)complies with Standards 2, 3 and the pretreatment and structural BMP requirements of Standards 4-6 to the maximum extent practicable and (b) improves existing conditions. Standard 8: Construction Period Pollution Prevention and Erosion and Sedimentation Control A Construction Period Pollution Prevention and Erosion and Sedimentation Control Plan must include the following information: • Narrative; • Construction Period Operation and Maintenance Plan; • Names of Persons or Entity Responsible for Plan Compliance; ' • Construction Period Pollution Prevention Measures; • Erosion and Sedimentation Control Plan Drawings; • Detail drawings and specifications for erosion control BMPs, including sizing calculations; • Vegetation Planning; ' • Site Development Plan; Construction Sequencing Plan; • Sequencing of Erosion and Sedimentation.Controls; ' • Operation and Maintenance of Erosion and Sedimentation Controls; • Inspection Schedule; • Maintenance Schedule; ' • Inspection and Maintenance Log Form. ® A Construction Period Pollution Prevention and Erosion and Sedimentation Control Plan containing the information set forth above has been included in the Stormwater Report. swcheck.doc•04/01/08 Stormwater Report Checklist•Page 7 of 8 i ' Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checklist for Stormwater Report tChecklist (continued) Standard 8: Construction Period Pollution Prevention and Erosion and Sedimentation Control ' (continued) ❑ The project is highly complex and information is included in the Stormwater Report that explains why it is not possible to submit the Construction Period Pollution Prevention and Erosion and Sedimentation Control Plan with the application. A Construction Period Pollution Prevention and Erosion and Sedimentation Control has not been included in the Stormwater Report but will be submitted before land disturbance begins. ❑ The project is not covered by a NPDES Construction General Permit. ❑ The project is covered by a NPDES Construction General Permit and a copy of the SWPPP is in the t Stormwater Report. ` ® The project is covered by a NPDES Construction General Permit but no SWPPP been submitted. The SWPPP will be submitted BEFORE land disturbance begins. ' Standard 9: Operation and Maintenance Plan ® The Post Construction Operation and Maintenance Plan is included in the Stormwater Report and includes the following information: ® Name of the stormwater management system owners; ® Party responsible for operation and maintenance; ® Schedule for implementation of routine and non-routine maintenance tasks; ' ® Plan showing the location of all stormwater BMPs maintenance access areas; ❑ Description and delineation of public safety features; ' ❑ Estimated operation and maintenance budget; and ® Operation and Maintenance Log Form. ' ❑ The responsible party is not the owner of the parcel where the BMP is located and the Stormwater Report includes the following submissions: t ❑ A copy of the legal instrument(deed, homeowner's association, utility trust or other legal entity) that establishes the terms of and legal responsibility for the operation and maintenance of the project site stormwater BMPs; ❑ A plan and easement deed that allows site access for the legal entity to operate and maintain BMP functions. Standard 10: Prohibition of Illicit Discharges ' ® The Long-Term Pollution Prevention Plan includes measures to prevent illicit discharges; ' ® An Illicit Discharge ComplianceStatement is attached; ❑ NO Illicit Discharge Compliance Statement is attached but will be submitted prior to the discharge of any stormwater to post-construction BMPs. swcheck.doc•04/01/08 Stormwater Report Checklist•Page 8 of 8 t Long Term Pollution Prevention Plan (LTPPP) "The Woodlands" (Clark Avenue) Salem, Massachusetts August 31, 2015 ' This Long Term Pollution Prevention Plan has been prepared to comply with the provisions set forth in the Massachusetts Department of Environmental Protection(DEP) Stormwater Management ' Standards.Structural Best Management Practices (BMPs) require periodic maintenance to insure proper function and efficiency in pollutant removal from stormwater discharges that would otherwise reach wetland resource areas untreated. Maintenance schedules found below are as recommended in Department of Environmental Protection's Massachusetts Stormwater Handbook and as recommended in the manufacturer's specifications. I. Street Sweeping: The streets shall be swept twice a year preferably but at the very least once per year in the spring II. Ownership and Maintenance Responsibilities: ' To the best of our knowledge,after completion of the The Woodlands Subdivision the City of Salem will assume full responsibility of continuing the operation and maintenance of the stormwater management system as well as the long term pollution prevention plan outlined below unless a legally-binding agreement is made with another party to perform such duties. ' III. DEP Standard 4:Water Ouality The Long Term Pollution Prevention Plan includes the following: A. Good housekeeping practices; ' Prevent or reduce pollutant runoff from reaching the wetland resource areas through street sweeping,stabilizing all disturbed areas with vegetative cover,catch basin cleaning and cleaning the sediment&oil separator units. B. Provisions for storing materials and waste products inside or under cover; All materials on site are to be stored in a neat and orderly fashion in their appropriate containers and,if possible,under a roof or other secure enclosure. All waste products are to be placed in secure receptacles until they are emptied by a solid waste management company licensed in the Commonwealth of Massachusetts. C.Vehicle washing controls; The Homeowners Association shall encourage residents to wash their vehicles on ' lawn or gravel areas so that the ground can filter the water naturally. This will prevent soap, dirt and oil from reaching the storm drains and ultimately wetlands, streams,rivers or marine waters: Encourage residents to wash their vehicles at t commercial car washes which recycle water and use approximately 60% on average of the amount of water used in a home wash. Long Term Pollution Prevention Plan The Woodlands Subdivision, Salem, MA ' August 31, 2015 D. Requirements for routine inspections and maintenance of Stormwater BMP's; Follow the procedures outlined in the Operation and Maintenance Plan as well as the provided Long Term Inspection and Maintenance Forms. E.Spill prevention and response plans; Spill Prevention: As mentioned previously,all materials on site are to be stored in a neat and orderly fashion in their appropriate containers and, if possible,under a roof ' or other secure enclosure. Products shall be kept in their original containers with the original manufacturer's label. Products should not be mixed unless recommended by the manufacturer. The manufacturer's recommendations for proper use and disposal shall be followed at all times and,if possible,all of the product should be used up before proper disposal. Response: The manufacturer's recommended methods for cleanup must be followed and spills cleaned up immediately after discovery. Spills shall be kept well ventilated and personnel must wear appropriate protective gear to prevent injury from contact ' with hazardous substances. Spills of toxic or hazardous material,must be reported to the appropriate local and/or State agencies in accordance with the local and/or Commonwealth of Massachusetts regulations. F. Requirements for storage and use of fertilizers,herbicides and pesticides; Consult the Order of Conditions issued by the City of Salem Conservation Commission for any questions regarding these materials. Fertilizers: Fertilizers are to be applied.at the minimum amounts recommended by the manufacturer and once applied shall be worked into the soil to limit the possibility of entering the storm drains. Storage procedures are to be followed as previously stated and the contents of any partially used bags should be transferred to i ' a sealable container,either bag or bin to avoid spilling. Herbicides and Pesticides:Storage of these materials are to be as outlined previously and especially out of the reach of pets and children,away from damp areas where their containers may succumb to moisture or rust and should not be stored near food. These materials must not be placed in the trash or washed down the drain. Handle t using rubber gloves and use an appropriate mask when using these products for extensive periods of time. G. Provisions for maintenance of lawns,gardens,and other landscaped areas; These activities are to be left up to the individual homeowner's to schedule and ' perform: H. Pet waste management provisions; These activities are to be left up to the individual homeowner's to schedule and perform. I � 2 Long Term Pollution Prevention Plan The Woodlands Subdivision, Salem, MA ' August 31, 2015 I. Provisions for operation and maintenance of septic systems; Not applicable, project will be connected to municipal sewer. J. Provisions for solid waste management; ' All waste products are to be placed in secure receptacles until they are emptied by a solid waste management company licensed in the Commonwealth of Massachusetts. ' K.Snow disposal and plowing plans relative to Wetland Resource Areas; Snow disposal/removal is to be in compliance with the Bureau of Resource Protection's (BRP's)Snow Disposal Guidelines effective March 8,2001,Guideline No. ' BRPG01-01. L. Winter Road Salt and/or Sand Use and Storage restrictions; ' Road Salt:Storage is to be as mentioned previously and the use must be in compliance with the Guidelines on Deicing Chemical (Road Salt)Storage effective date December 19,1997,Guideline No. DWSG97-1 found in the BRP's Drinking ' Water Program. Sand Use: Encourage the use of environmentally friendly alternatives such as calcium chloride and/or sand instead of road salt for melting ice whenever possible. M.Street Sweeping schedules; As mentioned previously,street sweeping should be performed by the City twice per i ' year in the spring and fall;however,at the very least sweeping must occur once a year in the spring in order to minimize the amount of Total Suspended Solids load on ' the deep-sump catch basins and the other Best Management Practices tributary thereto. i ' N. Provisions for prevention of illicit discharges to the stormwater management systems; There are no proposed illicit discharges to the proposed stormwater management systems as can be seen on the Definitive Plans. According to Standard 10 in the Massachusetts Stormwater Handbook,Illicit discharges to the stormwater management system are discharges that are not entirely comprised of stormwater. Notwithstanding the foregoing,an illicit discharge does ' not include discharges from the following activities or facilities: firefighting,water line flushing,landscape irrigation,uncontaminated groundwater,potable water sources,foundation drains,air conditioning condensation,footing drains,individual ' resident car washing,flows from riparian habitats and wetlands,dechlorinated water from swimming pools,water used for street washing and water used to clean residential buildings without detergents. O. Documentation that Stormwater BMP s are designed to provide for shutdown and ' containment in the event of a spill or discharges to or near critical areas or from land uses with higher potential pollutant loads (LUHPPL); Not applicable as this project does not meet the criteria for a LUHPPL. 1 3 1 i Long Term Pollution Prevention Plan The Woodlands Subdivision, Salem, MA ' August 31, 2015 O. Training for staff or personnel involved with implementing LTPPP; ' This responsibility lies with the Owner until after completion of the Stone Ridge Heights Subdivision when the Homeowner's Association will assume full responsibility unless a legally-binding agreement is made with another party to ' perform such duties for the Homeowner's Association. P. List of Emergency contacts for implementing Long-Term Pollution Prevention Plan; ' This responsibility lies with the Owner until after completion of the Stone Ridge Heights Subdivision when the Homeowner's Association will assume full responsibility unless a legally-binding agreement is made with another party to ' perform such duties for the Homeowner's Association. 1 I ' I 4 LONG-TERM INSPECTION AND MAINTENANCE REPORT FORM (LONG-TERM POLLUTION PREVENTION PLAN) ' THE WOODLANDS (CLARK AVENUE) SALEM, MA ' TO BE COMPLETED EVERY 7 DAYS DURING CONSTRUCTION TO BE COMPLETED WITHIN 24 HOURS OF A RAINFALL EVENT OF 0.5 INCHES OR GREATER FOUR TIMES PER YEAR THEREAFTER OR WHEN ' SEDIMENT ACCUMULATES TO A DEPTH OF 12 INCHES OR GREATER. Name of Inspector: Date: Inspectors Company/Affiliation: Days Since Last Rainfall: Amount of Last Rainfall: ' :a r� 'f -�' tiS3"on� rYA.— ? .{ ,+i+r"�c rtiR" J' �✓ yt-ii n'" S ji"F.J}y 4fy"'1 -l.rJ�"cf`� wv '"4,� +.-+ - ,rS.ylQ��-. 4 � k� ^ � ✓ �' tY i t r ; :sl b y � r ir�•Yf `u iz%{v 5 f E+'• t5F'-q.?t #�yf S.i b5. "'t'lr ...r +. , SEL w:J 'f •' ✓r tie r f c t a^'T °- ih cx� 5- b 57* 5 f..,., tt r t�� 3 1 xn <w^ }-.. `.. +� 1+,e5.+ �p„r t'^ Ft7. '?. ;,�i � ti rt�., da l J SyS N 0.'3 c + z•ti1,.' 74.:i'..' :�'uj2 _ ti_.r •a.?.'�t''i�..a.;2,_...w :.3_y.sr vlz�`��a�li,-_,:a Tt�;..a.:xi}1 �.t�,:�w°�.�2�.i�'.x'>_c';;i��..��u i�`�+Y..`t�. -.� ^-s- - 't^� R Sf' '•� �� i ' 6". r F +,5 '(q d M vh.4 F + "•t ay*s 6 +-. 4t aN- ,.rs > p f�r rK, [� vltr-sa. �. t a3� F°+'�, ps `aB_UIIdU11 s ` c V rail � .. ,Streets , . i Station ' v Lefty Ri ht HootlSinstalledt �nchesL Contl�twn_, t pp.,w�?"f CC� `:l'4 #,i y 7/"".'°".Y^y m.c�'av�StY x�t-ltd^ 'aTM e�q �4 eTftai 'w .�f`n'�"L' � w it-"'+.N: q '�.y.{�a✓ tea, � �t� t�4 tier~ POOP s. yes - n0 fair a r,.cis M, ra ;e ood r POOP Yes - no fair good POOP + e yes no fair � good poor >� h yes - n0 fair r P oor �^' T ♦f_'r 4 T t''Li pp yes - no fair G Udti f s� 1INN -�,-".Lh1Fi eTt'f4 �t ood Poor d Sy 4r rwpdk ad'` �, Asa: yes - no fair - ' good Maintenance Required: t To Be Performed By: On of Before: i ' LONG-TERM INSPECTION AND MAINTENANCE REPORT FORM (LONG-TERM POLLUTION PREVENTION PLAN) ' THE WOODLANDS (CLARK AVENUE) . SALEM, MA TO BE COMPLETED EVERY 7 DAYS OR WITHIN 24 HOURS OF A RAIN FALL EVENT OF 0.5 INCHES OR GREATER TO BE COMPLETED TWICE PER YEAR FOR FIRST THREE (3) YEARS AFTER COMING ON-LINE AND THEN ONCE PER YEAR THEREAFTER tName of Inspector: Date: ' Inspector's Company/Affiliation: Days Since Last Rainfall: Amount of Last Rainfall: � avr �'+'�?P"Fu�T w tjT�y7" .+.,rlF rff�•`�i�p�#fa£` ?'tx SH�' : 111Controls D.etentton Basms � " m; � ... WSW "sI`t . r , , � Condition of ;g. owMuch Sediment How MuchfSed�mentABurld Steuctur ,y a• S dewSlopes3 ,Bu�ltl u}p' ;Basn� up aty�ingm, yet ; Identficatro_nhw# 4%�V,e etat `ed s%, ,Circle, one _ ACCUmu'lation)f Ysf. 5"' ' ` XibyRp4fear S.�`°4E ,j''F,-• ",,.r-.c aF, eit"4`v1. +�fdr' Y'nQG �m .7 " 1s �_ x minor/ moderate / major minor/ moderate / major a� or minor/ moderate /ma .> .z a•� . x� . 1 : + K * minor/ moderate / major Maintenance Required: 1 ' To Be Performed By: On of Before: LONG-TERM INSPECTION AND MAINTENANCE REPORT FORM (LONG-TERM POLLUTION PREVENTION PLAN) ' THE WOODLANDS (CLARK AVENUE) SALEM, MA ' TO BE COMPLETED EVERY 7 DAYS OR WITHIN 24 HOURS OF A RAINFALL EVENT OF 0.5 INCHES'OR GREATER DURING CONSTRUCTION TO BE COMPLETED TWICE PER YEAR FOR FIRST THREE (3) YEARS AFTER COMING ON-LINE AND THEN ONCE PER YEAR THEREAFTER ' Name of Inspector: Date: Inspectors Company/Affiliation: iDays Since Last Rainfall: Amount of Last Rainfall: �"` x s -' y". ♦„e '°�„ °a�'L" "-.a ��,t � a � $-s .q - .�- y +o"vTv-4 is �'a4 _'-+'ei�'4.s<v sa �� �tStructural�.Controls :Outlet);ControlES,tructures�for�DetentionYBasins�-� a,,� �� r�- ek t,yr y-.Fµ a� .r z sa I-i ! S+r • Y < ,wa "e f `�. FNli )Y K ... ��,� a e4P�r mss. l!��..._.'._( L{♦d L F 1�A YK"'�ayt 1 }mf }'� .� Yy /' r � „� 1♦ ? }� ,k Y1�{t l� r4 Y S-. 1j4 aYY� 4} 44 { �4JY" Y f £ a! -♦ �y �b T Y: � � x �� 1,..e '� } 3 �a' � .� 1..E; 1s' � a'C� V ,FM1�'f� fi a � -•r'S� �fjvJ ���L��" ��b Z s "'1 � q < t.� fi � 4.: 1 l3. t , � + fi H ;• > � 4 "1� y .;�i .,w � r �sf.r'"�s s t 5.« �s v h t.L� -' b � S"F., ti s �y t'f�� #�l r ✓�'V-uF l'�. i .v -`� ��'? ion `M 3 %� . infiltratronBasin,� i Prpe/Qnfice SedrmentD'e thF�Condrtronof,?Enver enc r�.r, : 'Identi_fication f ` Cgnditlons �t.", . .,, ' mclies w t. S �y x= tSS ?new v' tC'� r #fij1 ify'1n9 Cwt , 4N Lr ;ti ♦ y ' � y6 �a - Maintenance Required: ' To Be Performed By: On of Before: ' LONG-TERM INSPECTION AND MAINTENANCE REPORT FORM (LONG-TERM POLLUTION PREVENTION PLAN) THE WOODLANDS (CLARK AVENUE) SALEM; MA TO BE COMPLETED EVERY 7 DAYS OR WITHIN 24 HOURS OF A RAINFALL EVENT OF 0.5 INCHES OR GREATER DURING CONSTRUCTION ' TO BE COMPLETED TWICE PER YEAR FOR FIRST THREE (3) YEARS AFTER COMING ON-LINE AND THEN ONCE PER YEAR THEREAFTER ' Name of Inspector: Date: Inspector's Company/Affiliation: ' Days Since Last Rainfall: Amount of Last Rainfall: Days Since Last Rainfall: Amount of Last Rainfall: ,:..i yx �4�1 fi-5^ r <•'�'i' £ � � �.. -1 �,. �� �'Vi'd.x H.`. 7 {5#�2�a � � tL el.�`.>;- H �St �e y� Y' <� v� Aw -� R � �` i'1,. ''�'�, t x L `z.�•;_,F4„,'S, 'ttv.q'S'..` rQi'2 5+s Tv�. � i<�g`.,. i .i- ��'� M ��.. y ., r b � i s T •3r "�' 4S h d �5 `w]'>y, b v ; I`" 4 g t —�- r ¢"�a' ..�5IFOIA r� ' } i o-T` nrs �lIdup �3f �x'I Streenolc L s� yy, �r �'. # f p�{may SkA PrF r� Z POOr }p4 L yes - no fair good poor yes - no fair good poor yes - no fair good poor yes - n0 fair an- S' 'i `a Fryer � : z _ _� s�; ood poor yes - no fair good ' Maintenance Required: To Be Performed By: On of Before: Construction Period Pollution Prevention Plan and Erosion and Sedimention Control `" .` f�""'a*�%. - F 7:$I•fE1D;,ES�CRIP'FION;a� ,�aw'�,�,; , `�� '��-.,*" - "; Pkgectame�and3 The Woodlands aAp�pl }nName ` NSD Realty Trust ' locapon (Latitud'e Clark Avenue and AdiJcess 76 Oakville Street ��f- n L nn, MA 01905 lon rtud�uor'Atldress w+ Salem, MA � >�r, �Cnptlo y(Pupose ,' This project involves the construction of two paved roadways to provide access for nd'sTypes:ofsSoil a 26 lot cluster residential subdivision and one additional lot zoned D most)stufi'ui (Activities :, industrial y Soil disturbing activities inlcude: earth&ledge' removal, clearing and grubbing;installation of erosion and sediment control device, pavement installation, utility installation, home construction, landscaping and preparation for final loaming and seeding. ' Ri ioff Goeffciei>t:0 The final composite runoff coefficient for the site is approximately 0.4 ' SrterArea The site is approximately 17.2 acres of which approximately 8 5 acres � ' will be disturbed by construction activities. S G'ence of`Ma oKX66rGes x s $t " The order of activities shall be as follows: 1. Install construction entrances 9. Finished grading and slope stabilization 2. Install.erosion control devices 10. Finished Paving ' 3. Clearing, cutting and grubbing 11. Loam and seed all disturbed areas. 4. Rough grading 12. Final cleanup including inspection and 5. Utility Installation cleanout of all stormwater structures. ' 6. Gravel and pavement base course installation 7. House lot construction 8. Curbing and sidewalk construction ' Name oftRecet3tngsThe site is tributary to wetlands that are tributary to the Forest River Waters �5 �"+ �I: �s�FL t���x . �,�fi"'„tq�'C,ONTROLS f,'������` ���.��s•�ar�`� Temporary Stabilization On sediment producing areas, where the period of exposure is more than two months, but less than 12 months, the following procedure should be followed: a install needed surface water control measures, b. perforin all cultural operations at right angles to the slope, c. establish adapted species from Table 1 below, d. apply seed uniformly to the rate indicated by broadcasting or hydraulic application;and e. cover seed with mulch as needed. ' Permanent Stabilization -To reduce damages from sediment and runoff to downstream areas, and to avoid erosion on the site itself, a permanent type cover shall be established as soon as possible. Seeding herbaceous cover is usually the most economical and practical way to stabilize any large area. On this site a permanent cover utilizing standard commercial seed mixes containing species similar to Mixtures#3,#4, and #7 is appropriate. Sod or erosion control blanket infused with one of the aforementioned seed mixtures may be installed as permanent cover on the site at the Owner's discretion (See Table 2). 1 x�yf r , z ir ' ' t� CONTROLS (Cgnttnuetl) e `:�� t- ,err:} r � .. y_11 r,,,,. r- _ 4 p,,s'�yrmtt u da .;+ ; IMIXTURE NO. 1 -Dry to Very Dry Sites Switchgrass -20 lbs. (Blackwell or Nebraska 26) Redtop-3 lbs; or Annual Ryegrass - 15 lbs. Switchgrass seed requires a chilling period of three (3)weeks or longer at common household refrigerator temperatures, except when seeded in late fall or winter. Regular mowing should not be practiced. Very slow growing the first year. MIXTURE NO. 2 -Dry to Very Dry Sites ' Weeping Lovegrass -5 lbs. Cape and the Islands only. May be killed by severe winters, and should not be seeded where regular mowing will be practiced. Spring seeding only between April 15 and May 15. Should not be used for sand dune stabilization. MIXTURE NO. 3 -Moderately Moist to DrySites Red fescue-30 lbs. Redtop -3 lbs.; or Perennial Ryegrass - 15 lbs. Resistant to foot traffic. Tolerant of shade. Good for lawn type cover. MIXTURE NO.4-Moderately Moist to Very Dry Sites Tall fescue-40 lbs. ' Redtop -3 lbs.; or Perennial Ryegrass - 15 lbs. Resistant to foot traffic when well established. Tolerant of shade. MIXTURE NO. 5-Very Moist to Dry Sites Reed canarygrass -20 lbs. Redtop-3 lbs.; or Perennial Ryegrass - 15 lbs. On moist and very moist sites, reed canarygrass can be established quicker by planting rootstocks. r 1 ' CONTROLS (Continued) , . „ Table 2 contd ..� ' MIXTURE NO 6 Moderately Moist to Dry Sites ' Crown vetch - 15.lbs. Redtop -3 lbs.; or Perennial Ryegrass - 15 lbs. Crown vetch should not be seeded as the basic species where regular mowing will be practiced. Spring seeding is preferred. MIXTURE NO. 7 -Moderately Moist to Dry Sites ' Standard commercial grass or grass-legume mixtures used for lawns or long-term forage crop production. Mixtures should contain at least 75% perennial grasses or legumes. Annual fertilization should be planned. ' MIXTURE NO.8 -Moderately Moist Sites Kentucky Bluegrass -20 lbs. ' Redtop-2 lbs.; or Perennial Ryegrass - 15 lbs. Only for high-fertility sites, usually four(4") inches or more topsoil. Good for lawn-type cover. ' MIXTURE NO. 9 -Moderately Moist to Very Dry Sites Sericea Lespedeza -20 lbs. ' Redtop-2 lbs.; or Perennial Ryegrass - 15 lbs. Cape and the Islands only, and seeded only in the spring. Should not be seeded where regular mowing will be practiced. ' REFERENCE United States Department of Agriculture, Soil Conservation Service, 1977. Guidelines for Soil and Water Conservation in Urbanizing Areas of Massachusetts. U.S.D.A. Soil Conservation Service, Amherst, Massachusetts, 88 pages. t 1 1 1 t tCONTROLS(Continued) al sedimentation of the downstream wetland She ap approved OIl " ' Silt Fencing -shall be installed as shown on the approved NOI Plan to help prevent erosion and resources identified on the project. Catch Basins -shall be fitted with filter fabric during construction to prevent the accumulation of sediments in the catch basin sump. Catch Basin is to be cleaned as specified in the Long Term Pollution Prevention Plan. StonnwaterManagement . ' The stormwater runoff shall be managed through the use of several best management practices: 1. Deep Sump Catch Basins w/hood 2. Oil &Sediment Separator Units 3. Detention Basins ' 4. Subsurface Infiltration Structure ' ::!PT PE ONTROLS aste.flis bsal J Waste Materials: All waste materials shall be collected and stored in secure metal dumpsters rented from a licensed solid waste management company in Massachusetts. The dumpsters shall meet all local and state solid waste management regulations as outlined in 310 CMR 19.00. All trash and construction debris generated on site shall be disposed of in the dumpsters. The dumpsters shall be emptied as often as necessary during construction and transferred to an approved solid waste facility licensed to accept municipal solid waste and/or construction and demolition debris. No construction waste shall be buried on site. All personnel shall be instructed regarding the correct procedure for waste disposal. Hazardous Waste: All hazardous waste materials shall be disposed of in a manner specified by local or ' State regulation or by the manufacturer. Site personnel shall be instructed in these practices. Sanitary Waste: All sanitary shall be collected from portable units, as needed, by a licensed septage hauler in Massachusetts, in accordance with the requirements of the local Board of Health. ' OTHER CONTROLS•(continued) Offsite Vehicle TraZM : ' Construction entrance and exit shall be via Clark Avenue. - 'TIMING OF-CONTROLS/MEASURES ' As indicated in the Sequence of Major Activities, the installation of erosion and sediment control devices shall be in place prior to earth excavating activities. CERTIFICATION OF•COMFLIANCEOIVITIII FEDERAL,STATE,-AND LOCAL REGULATIONS The stormwater pollution prevention plan reflects the requirements of the Massachusetts Wetlands Protection Act(MGL c.131, section 40). There is no wetland filling associated with this project. It is strictly a buffer zone project. Note that there are no other applicable State or Federal requirements for sediment and erosion ' control plans(or permits), or stormwater management plans (or permits) required for this project to the best of our knowledge. VA ffllyT jEnA CP 4NSP:ECT}ON PROCEDURES ' Erosioniind'SWirtiiCrritpbiitr6llrVt eaioband_Maintenance_Practices The following items represent the inspection and maintenance practices that will be used to maintain sediment and erosion control for'The Woodlands"subdivision project. t1. All control measures shall be inspected at least once every fourteen (14)days and following any storm event of 0.5 inches or greater. ' 2. All measures shall be maintained in good working order; if a repair is necessary, it shall be initiated within 24 hours of the report. ' 3.. Built up sediment shall be removed from sift fencing when it has reached one-third the height of the fence. 4. Sift fence shall be inspected for depth of sediment,tears,to see if the fabric is securely attached to the fence posts, and to see that the fence posts are firmly set in the ground. 6. The catch basin grates shall be inspected for grate elevation relative to current surface condition; condition of fitter fabric, and degree to which sediment has accumulated on the grate and in the sump of the catch basin. 1 ' 1 ' MAINTENANCE/,INSP,ECTION,P,ROCEDURES,(Continued) ' �Erosioo�and_Sedir ent'Coritrol;lrfs -ction and Maintenance'.P.ractice'r Continued 7. Temporary and permanent seeding and any plantings shall be inspected for bare spots, washouts, and healthy growth. 8. A maintenance inspection report shall be prepared following each inspection. A copy of the report form to be completed by the inspector is attached to the LTPPP. ' 9. NSD Realty Trust shall select three individuals who will be responsible for inspections, maintenance and repair activities as well as who shall be responsible for filling out the inspection and maintenance report. ' 10. Personnel selected for inspection and maintenance responsibilities shall receive training from NSD Realty Trust or their designated representative. They will be trained in all the inspection and maintenance practices necessary for keeping the erosion and sediment control devices used on site in good working order. Non StormwaWjDischa=`es_ It is expected that the following non-stormwater discharges will occur from the site during the construction i period: 1. Water from water line flushing. 2. Pavement wash waters. All non-stormwater discharges shall be directed to the proposed site BMPs prior to discharge. 1 1 ' INVENTORY'FOR POLLUTION PREVENTION PLAN ' The materials or substances listed below are expected to be present on site during construction: x Concrete x Fertilizers x Wood x Petroleum Based Products x Structural Steel x Cleaning Solvents x Masonry Block x Paints (enamel and latex) ' x Othe Building Materials x Tar x Fiber Glass Insulation x Waterproofing Materials SPILL'PREVENTION ' Material Management Practices The following are the material management practices'that shall be used to reduce the risk of spills or other accidental exposure of materials and substances to stormwater runoff. 1 Good'Housekee in ' The following good housekeeping practices will be followed on site during the construction project. 1. A concerted effort shall be made to store only enough product required to complete a particular task. 2. All materials stored on site shall be stored in a neat and orderly fashion in their appropriate containers and, if possible, under a roof or other secure enclosure. 3. Products shall be kept in their original containers with the original manufacturer's label. 4. Substances shall not be mixed with one another unless recommended by the manufacturer. ' 5. Whenever possible, all of a product shall be used up before disposing of the container. 6. Manufacturers recommendations for proper use and disposal shall be followed. ' 7. The site superintendent shall inspect daily to ensure proper use and disposal of materials on site. Hazardous Products The following practices are intended to reduce the risks associated with hazardous materials. 1. Products shall be kept in original containers unless they are not resealable. ' 2. Where feasible, the original labels and material safety data shall be retained, whereas they contain important product information. 3. If surplus product must be disposed, follow manufacturers or local and State recommended methods for proper disposal. I ' SPILL PREVENTION(Continued) . _- Product Specific Practices The following product specific practices shall be followed on site ' Petroleum'Products:, All on site vehicles shall be monitored for leaks and receive regular preventative maintenance to reduce the ' risk of leakage. Petroleum products shall be stored in tightly sealed containers which are clearly labeled. Any bituminous concrete or asphalt substances used on site shall be applied according to the manufacturers recommendations. ' Fertilizers'. Fertilizers shall be applied in the minimum amounts recommended by the manufacturer. Once applied, fertilizers shall be worked into the soil to limit exposure to stonnwater. Storage shall be in a covered shed or trailer. The contents of any partially used bags of fertilizers shall be transferred to a sealable plastic bag or bin to avoid spills. Paints: ' All containers shall be tightly sealed and stored when not required for use. Excess paint shall not be discharged into any catch basin, drain manhole, or any portion of the stormwater management system. Excess paint shall be properly disposed of according to manufacturer's recommendations or State and local regulations. ' Concrete Trucks;. Concrete trucks shall not be allowed to wash out or discharge surplus concrete or drum wash water on site. S`ill:Cont d Practices ---- - -----In addition to the good housekeeping and material management practices discussed in the previous sections of this plan, the following practices shall be followed for spill prevention and cleanup: 1. Manufacturer's recommended methods for cleanup shall be readily available at the on site trailer and site personnel shall be made aware of the procedures and the location of the information. 2. Materials and equipment necessary for spill cleanup shall be kept in the material storage area on site. Equipment and materials shall include, but not be limited to brooms, dust pans, mops, rags, gloves, goggles, kitty litter, sand, sawdust, and plastic and metal trash containers specifically for this purpose. 3. All spills shall be cleaned up immediately after discovery. 4. The spill area shall be kept well ventilated and personnel shall wear appropriate protective clothing to prevent injury from contact with a hazardous substance. 5. Spills of toxic or hazardous material shall be reported to the appropriate State and/or local authority in ' accordance with local and/or State regulations. 6. The spill prevention plan shall be adjusted to include measures to prevent a particular type of spill from reoccurring and how to clean up the spill if there is another occurrence. A description of the spill, what caused it, and the clean up measures shall also be included. 7. NSD Realty Trust or their assigned designee shall be the spill prevention and cleanup coordinator. NSD Realty Trust shall designate at least three other site personnel who will be trained in the spill control practices ' identified above. 1 „POLLUTION.PREVENTION;PLAN',CERTIFICATION. fir,. I certify under penalty of law that this document and all its attachments were prepared under my direction or supervision in accordance with a system designed to assure that ' qualified personnel properly gathered and evaluated the information submitted. Based on my inquiry of the person or persons who manage the system, or those persons directly responsible for gathering the information, the information submitted is, to the best of my knowledge and belief, true, accurate, and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fine and imprisonment for knowing violations. ' Signed: Nick Meninno ' NSD Realty Trust Date: t The Woodlands (Clark Avenue) CONSTRUCTION PERIOD POLLUTION PREVENTION PLAN INSPECTION AND MAINTENANCE REPORT FORM TO BE COMPLETED EVERY 14 DAYS AND WITHIN 24 HOURS OF A RAINFALL EVENT OF 0.5 INCHES OR GREATER Inspector: Date: Inspector's Title: Days Since Last Rainfall: Amount of Last Rainfall: iStructural Controls: Silt Fencing Average Are Fence iDepth of Tears Posts Secure? Overall From To Sediment (yes/no) (yes/no) Condition i poor yes - no yes - no fair igood poor yes - no yes - no fair ' good poor yes - no yes - no fair igood poor yes - no yes - no fair igood poor yes - no yes - no fair i good Maintenance Required: 1 i i To Be Performed By: On or Before: i i The Woodlands (Clark Avenue) CONSTRUCTION PERIOD POLLUTION PREVENTION PLAN INSPECTION AND MAINTENANCE REPORT FORM t TO BE COMPLETED EVERY 14 DAYS AND WITHIN 24 HOURS OF A RAINFALL EVENT OF 0.5 INCHES OR GREATER ' Inspector: Date: Inspector's Title: Days Since Last Rainfall: Amount of Last Rainfall: Structural Controls: Existing Catch Basins and Grates ' Is Catch Basin Is Filter Fabric Sediment Buildup Sediment Buildup Grate to Grade in Placeon Grate and Fabric in CB Sump Location es or no es or no minor/moderate/maor (0- 100%) es — no yes — no minor/moderate/ma'or es — no yes — no minor/moderate/major es — no yes — no minor/moderate/ma'or ' es — no yes — no (minor/mode te/major es — no yes — no minor/moderate/major) ' es — no yes — no minor/moderate/major es — no yes — no minor/moderate/maor es — no yes — no minor/moderate/ma'or ' Maintenance Required: 1 1 1 To Be Performed By: On or Before: 1 1 i The Woodlands (Clark Avenue) CONSTRUCTION PERIOD POLLUTION PREVENTION PLAN INSPECTION AND MAINTENANCE REPORT FORM ' TO BE COMPLETED EVERY 14 DAYS AND WITHIN 24 HOURS OF A RAINFALL EVENT OF 0.5 INCHES OR GREATER ' Inspector: Date: Inspectors Title: Days Since Last Rainfall: Amount of Last Rainfall: Detention Basins Condition of Condition of How Much Forebay Forebay Sediment Buildup Description Side Slopes Side Slopes Circle one ' minor/ moderate/major minor/moderate / major ' minor/ moderate / major minor/moderate / major minor/ moderate / major i , Maintenance Required: 1 ' To Be Performed By: On or Before: t ' The Woodlands (Clark Avenue) CONSTRUCTION PERIOD POLLUTION PREVENTION PLAN (CPPPP) INSPECTION AND MAINTENANCE REPORT FORM ' CHANGES REQUIRED TO THE POLLUTION PREVENTION PLAN: 1 ' REASONS FOR CHANGES: I certify under penalty of law that the above changes to the document and all its attachments were prepared under my direction or supervision in accordance with a system designed to assure that ' qualified personnel properly gathered and evaluated the information submitted. Based on my inquiry of the person or persons who manage the system, or those persons directly responsible for gathering the information,the information submitted is, to the best of my knowledge and belief, true, accurate, and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fine and imprisonment for knowing violations. SIGNATURE DATE I 1 Project No. SALE-0026 Applicant: ' NSD Realty Trust 76 Oakville Street 1 Lynn, MA 01905 1 Mitigative Drainage Analysis 1 1 "The Woodlands" Proposed Cluster 1 Residential Subdivision 1 Clark Avenue 1 Salem; Massachusetts 1 August 14, 2015 1 Revised: August 31, 2015 1 1 -yy� & WILLLAMS SPARAGES T S 189 North Main Street,Suite 101 Middleton,MA 01949 ' 978-539-8088 Ph 978-539$200 Fax www.wsengineers.com 1 I ' Proposed Cluster Residential Subdivision "The Woodlands", Salem, MA ' August 14, 2015 Revised: August 31, 2015 Purpose: The purpose of this analysis is to compare the present or existing conditions and the post- development or proposed watershed conditions for the proposed cluster residential subdivision by ' analyzing the surface runoff rates to the limit of the watershed analysis shown on the accompanying watershed maps: The results of which are presented on the summary tables that follow in order to comply with the requirements of the Salem Massachusetts Subdivision Regulations as well as the Massachusetts Department of Environmental Protection(DEP) ten(10) Standards. ' Introduction: The project is located on an presently vacant property (there is evidence of an old foundation on top of the hill) with an address of Clark Avenue in the City of Salem. The project is bounded to the north by residential properties located off of Clark Street, to the east by property owned now or formerly (n/f)by the City of Salem and to the south by properties located off of Wyman Place and ' n/f Lynn Sand &Stone Company located off of Robinson Road. The proposal is to build two roadways, the first is a one thousand and eighty-nine (1089.03') shown ' on the plans as"Woodlands Road", the second is a two hundred ninety-nine (298.99 ) shown on the plans as"South Ridge Circle' in order to provide access to a twenty-seven lot cluster subdivision. Lots 1 through 26 are in the R1 Zone•and will be a cluster residential subdivision,Lot 27 lies in both the Ri and I zones is not showing any development at this time on the proposed plans. The construction.of-the dwellings and roadway will.include paved driveways,lawn,landscaping, sewer, drainage, stormwater detention basins,a subsurface infiltration area,water services and other tvarious utilities. It should be noted that there are wetland resource areas located on the subject property-and we are ' proposing activities within the one-hundred(100')buffer zone to the edge of bordering vegetated wetlands. Therefore, a Notice of Intent(NOI) filing will be filed with the Salem Conservation Commission at a later date. Existing Condition Soils Analysis: tIn order to model the runoff parameters for both the existing and proposed watershed parameters, the parent soils on site were mapped using the Web Soil Survey (WSS) made available on the United States Department of Agriculture (USDA)National Resources Conservation Service (NRCS)website. The WSS provides vital soil data and information such as Hydrologic Soil Group (HSG) which is then input into a mathematical model to generate runoff curve numbers. The user inputs the soil cover type as wellas the hydrologic soil group to generate a weighted curve number(CN) and also uses the topography of the land.to generate a time of concentration (Tc) from ' which the stormwater runoff rate as well as volume may be calculated for a certain watershed for comparison. The soils present on site are comprised of Udorthents,smoothed and does not have a rating for its HSG with the NRCS. 2 I , Proposed Cluster Residential Subdivision "The Woodlands", Salem, MA r August 14, 2015 Revised: August 31, 2015 r The NRCS lists the majority of this property as being Chatfield-Hollis-Rock Outcrop Complex with hydrologic soil group B&C/D and a small portion on the southerly side as Whitman Loam with hydrologic soil group D. In order to be r consistent with the previously approved drainage analysis by Eastern Land Survey,we have assumed that the hydrologic soil group for the property is"C". We have also assumed that the limit of the hydrologic soil group"D" soils is coincident with the edge of bordering vegetated wetlands as shown on the accompanying watershed and soils maps. rFor the proposed subsurface infiltration pond and the surface detention ponds we have assumed a design infiltration rate of 0.27 in/hr. for"C" soils as found in the Hydrology Handbook for rConservation Commissioners, March 2002 Table 2-1. Stormwater Modeling Methodology: rThe mathematical model used in this analysis was provided using the HydroCAD Version 10.0 developed by HydroCAD Software Solutions LLC. HydroCAD is a program that is used to model r the hydrology and hydraulics of stormwater runoff and is based largely on programs and techniques developed by NRCS, specifically TR-20 and TR-55 as well as other hydraulic calculation methods. rHydroCAD allows the user,for a given rainfall event, to generate runoff hydrographs for single or multiple watersheds and is used to determine if a given drainage system is adequate under the rdesired conditions as well as to predict flooding or other impacts at specified locations such as erosion. rThree (3) design storm events were analyzed and the results presented in the tables that follow for the two (2) year,ten(10) year,and one-hundred (100) year storm events for comparison. rExisting Condition Watershed: r The limit of the watershed analysis has been delineated along the existing property lines and edge of bordering vegetated wetlands including the up gradient areas tributary thereto for comparison with the proposed condition as can be seen on the accompanying watershed maps. rUsing the methods described in the stormwater modeling explanation above,runoff curve numbers and times of concentration were generated for each watershed for the existing condition to be used for comparison with the proposed condition described below. A schematic of the mathematical model as well as the results of the calculations for the 2 year,10 year and 100 year,Type III,24-hour storm events are included in this report. r r r 3 r tProposed Cluster Residential Subdivision "The Woodlands", Salem, MA ! ' August 14, 2015 Revised: August 31, 2015 ' Proposed Condition Watershed The proposed development requires the construction of four (4) surface detention ponds and a ' subsurface infiltration pond to provide peak rate of runoff mitigation as well as groundwater recharge opportunities in the volume provided below the pond outlets. However,because the property has a lot of ledge and shallow to ledge areas,it is our opinion that there is not a lot of ' infiltration occurring in the exiting condition on site but is mostly shedding off. Runoff from the roadway, driveways and some of the roof areas will be collected using deep-sump ' catch basins with hoods from the paved surfaces and piped directly into the proposed stormwater management areas, see plan for locations. Three-quarters (3/4) of the proposed roof area on Lot 12 will be directly discharged to the proposed subsurface infiltration system shown on the plans. The remaining roof areas will discharge to the ground and then discharge overland or be infiltrated into the ground surface. Pretreatment for the subsurface infiltration system will be through the use of the deep-sump catch 1 basins with hoods and 1,500 gallon sediment&oil separator unit. The remaining stormwater I management areas will receive pretreatment from deep-sump catch basins and sediment forebays 1 with overflow spillways. The subsurface infiltration structure will be comprised of Cultec 330XL XD Heavy Duty Recharger ' units (or approved equivalent) connected together with internal manifolds and inspection ports brought to finish grade for maintenance and inspection. The structure will sit on a 6" crushed stone bed,have a 12" crushed stone border and will have a 6" crushed stone cover layer for additional ' storage volume. There are two(2)existing isolated wetlands that exist on the parcel shown as Lot 27 on the proposed ' subdivision plans. Although there is no proposed disturbance for these wetlands, the tributary area shown for EX-4R,the wetland higher on the slope,will have an increase in the amount of flow tributary to it as shown on the accompanying watershed maps. However,this is a non-jurisdictional j ' wetland and it is our position that.there will be no adverse impact due to the proposed construction activities. Using the methods described above,runoff curve numbers and times of concentration were generated for each watershed for the existing condition to be used for comparison with the t proposed condition described below. A schematic of the mathematical model as well as the results of the calculations for the 2 year,10 year and 100 year,Type III,24-hour storm events are included in this report. ' Conclusion: ' As can be seen by examining the following summary&performance tables, the proposed stormwater management system is effective for mitigating the peak flow rates of runoff from the limit of the watershed analysis for the 2, 10&100 year storm events. 1 4 ' Proposed Cluster Residential Subdivision "The Woodlands", Salem, MA August 14, 2015 Revised: August 31, 2015 ' Comparison Table Total Peak Rate of Runoff leaving project area Description 24 hour Type Existing Proposed ' III Condition Condition Storm Event Peak Rate of Peak Rate of ' (year) Runoff Runoff Q cfs. Q cfs. ' Flow towards 2 (3.1 inch) 5.1 4.6 ' Clarke Ave. 10 (4.5 inch) 9.7 8.1 Link 132L 100 (6.5 inch) 17.0 13.3 Flow towards 2 (3.1 inch) 7.6 6.9 ' the southem 10 (4.5 inch) 16.5 14.8 wetlands 100 (6.5 inch) 31.0 27.4 Link 139L Flow towards 2(3.1 inch) 4.8 4.5 ' the northern 10 (4.5 inch) 11.3 9.0 wetlands 100(6.5 inch) 22.2 16.6 Link 128L I , Total flow 2(3.1 inch) 12.1 10.9 ' discharging 10 (4.5 inch) 27.5 23.3 from project 100 (6.5 inch) 52.8 42.9 area ' Link 109L 5 ' Proposed Cluster Residential Subdivision "The Woodlands", Salem, MA ' August 14, 2015 Revised: August 31, 2015 Comparison Table Total Peak Rate tributary to non-j isdictional Isolated Wetlands Description 24 hour Type Existing Proposed III Condition Condition Storm Event Peak Rate of Peak Rate of (year) Runoff Runoff ' Q cfs. Q cfs. Flow towards 2(3.1 inch) 0.7 1.2 "B" Series 10 (4.5 inch) 1.7 2.6 ' Wetlands 100 (6.5 inch) 3.3 5.0 Link 130L Flow towards 2(3.1 inch) 0.7 0.7 "C" Series 10 (4.5 inch) 1.7 1.7 Wetlands 100 (6.5 inch) 3.5 3.5 Link 141L 6 i Proposed Cluster Residential Subdivision "The Woodlands", Salem, MA 1 August 14, 2015 Revised: August 31, 2015 Proposed Subsurface Infiltration Area HydroCAD Pond 78P (40) Cultec Recharger 330XL HD Units - 7 rows of 7 units Top of Stone=125.94 (25.67'x58.0(') ' Top of Chambers=125.44 12" Inv. In=124.33 Bottom of Chambers=122.90 ' Bottom of 6" Stone bed=122.40 ' Peak Rate of Runoff Out (Qout) cfs. ' 24 hour Type III Peak Rate of Storm Event Runoff In *Infiltration Overflow Total Peak Water (YR) (Qin)cfs. (Discarded) though Outflow Level (W.L.) ft. CB rim 2 0.7 0.01 0.0 0.01 124.00 10 1.2 0.01 0.0 0.01 125.56 100 1.9 0.01 0.69 0.70 "*127.91 ' *Calculated infiltration rate and peak water levels are based upon a rate 0.27 inches per hour for hydrologic soil group"C' found in the Hydrology Handbook for Conservation Commissioners, ' March 2002 Table 2-1. **'Phis system is designed to accept,store and infiltrate the 2&the 10 year storm events. Should the system become surcharged,for example,in the 100 year storm, the gutter flow in the proposed roadway will bypass the proposed catch basins located at the entrance and flow directly to the existing catch basin located on Clark Avenue Extension. The proposed catch basin located at ' station 0+0 Right will act as a secondary outlet and has been modeled as a weir with overflow adding to the Clark Avenue Extension drainage system The peak water level calculated will be lower than the proposed cellar floor grade for the house located on Lot 12, therefore,okay. 7 Proposed Cluster Residential Subdivision "The Woodlands", Salem, MA ' August 14, 2015 Revised: August 31, 2015 ' Detention Pond 1 HydroCAD Pond 142P t Top of Berm=136.5 Proposed Outlet Control Structure Bottom of Berm=132.0 Rim=136.50 8'L Emergency Stone Spillway=136.00 18" Pipe level @ 132.50 .12" RCP FES Inv. In=132.90 (From Road A) 4" Orifice.@ 132.50 8" Orifice @ 134.00 10" Orifice @ 134.50 12" RCP Inv.Out--131.50 Peak Rate of Runoff Out (Qout) cfs. 24 hour Type III Peak Rate of Stone Event Runoff In *Infiltration 12" 8'L Total Peak Water (YR) (Qin) cfs. (Discarded) .RCP Stone Outflow Level (W.L.) ft. Spillway 2 2.0 0.01 0.49 0.0 0.50 134.10 t10 3.8 0.01 1.82 0.0 1.83 134.73 100 6.6 0.02 4.05 0.0 4.07 135.34 *Calculated infiltration rate and peak water levels are based upon a rate 0.27 inches per hour for hydrologic soil group "C' found in the Hydrology Handbook for Conservation Commissioners, March 2002 Table 2-1. 8 ' Proposed Cluster Residential Subdivision "The Woodlands", Salem, MA ' August 14, 2015 Revised: August 31, 2015 Detention Pond 2 HydroCAD Pond 143P ' Top of Berm=132.5 Proposed Outlet Control Structure ' Bottom of Berm=128.5 Rim=132.50 8'L Emergency Stone Spillway=132.00 18" Pipe level Q 128.50 12" RCP FES Inv. In=133.00 (From Road A) 2.5" Orifice @ 128.50 ' 12" RCP Inv. Out=127.50 t Peak Rate of Runoff Out (gout) cfs. 24 hour Type III Peak Rate of ' Storm Event Runoff In *Infiltration 12" 8'L Total Peak Water (YR) (Qin)cfs. (Discarded) RCP Stone Outflow Level (W.L.) ft. Spillway i , 2 2.0 0.02 0.14 0.0 0.16 129.30 10 3.4 0.02 0.20 0.0 0.22 130.12 100 5.5 0.03 0.26 0.0 0.29 131.20 •Calculated infiltration rate and peak water levels are based upon a rate 0.27 inches per hour for hydrologic soil group"C' found in the Hydrology Handbook for Conservation Commissioners, March 2002 Table 2-1. 9 ' Proposed Cluster Residential Subdivision "The Woodlands", Salem, MA August 14, 2015 Revised: August 31, 2015 Detention Pond 3 HydroCAD Pond 152P Top of Berm=118.5 Proposed Outlet Control Structure ' Bottom of Berm=115.0 Rim=118.5 8'L Emergency Stone Spillway=118.0 18" Pipe level Q 115.50 12" RCP FES Inv. In=126.50 (Into Sediment Forebay) 8" Orifice @ 115.50 ' 12" RCP Inv.Out=113.50 ' Peak Rate of Runoff Out (Qout) cfs. ' 24 hour Type III Peak Rate of Storm Event Runoff In *Infiltration 12" 8'L Total Peak Water (YR) (Qin) cfs. (Discarded) RCP Stone Outflow Level (W.L.)ft. Spillway 2 2.3 0.02 0.79 0.0 . 0.81 116.06 10 4.0 0.02 1.48 0.0 1.50 116.60 100 6.6 0.02 2.07 0.0 2.10 117.35 ' *Calculated infiltration rate and peak water levels are based upon a rate 0.27 inches per hour for hydrologic soil group"C' found in the Hydrology Handbook for Conservation Commissioners, March 2002 Table 2-1. 1 10 ' Proposed Cluster Residential Subdivision "The Woodlands", Salem, MA ' August 14, 2015 Revised: August 31, 2015 1 ' Detention Pond 4 HydroCAD Pond 144P Top of Bern=122.5 Proposed Outlet Control Structure ' Bottom of Berm=117.0 Rim=122.5 8'L Emergency Stone Spillway=122.0 18" Pipe level Q 117.50 12 RCP FES Inv. In=122.00 (From Road A) 6 Orifice @ 117.50 ' 8" Orifice Q 120.50 12" RCP Inv. Out--114.50 Peak Rate of Runoff Out (gout) cfs. 24 hour Type III Peak Rate of Storm Event Runoff In *Infiltration 12" 8'L Total Peak Water r (YR) (Qin) cfs. (Discarded). RCP Stone Outflow Level (W.L.)it. Spill a 2 3.3 0.01 1.21 0.0 1.22 119.39 10 5.6 0.02 1.54 0.0 1.56 120.42 100 8.8 0.02 2.99 0.0 3.01 121.34 t *Calculated infiltration rate and peak water levels are based upon a rate 0.27 inches per hour for hydrologic soil group "C' found in the Hydrology Handbook for Conservation Commissioners, ' March 2002 Table 2-1. i 1 r r 1 1 1 , 1 1 1 1 , 1 1 Existing Condition 1 Watershed Analysis 1 1 1 i 1 1 1 1 1 1 1 1 EX-3 EX-RESI\ / �$ Ruofl sk mds6rp RuWf eLLttkip adM ba,Ye mClsk � wedmtdsb ,a1h .� Armee E1('2 Ruro6 WAVC13 lsoww E7F4 Wellerd'9',erw I "A X14 tido 10 a mnor", TMeI Sufa[e Rurnn RY o laved,Iadn E%S t / wetlmOe ro tle rgrfM dlsderpYp 6om pelea Wetlmtl'C,mles . Saes EX-RES 2 i ✓ V Drainage Diagram for N . A. ' _a11Y Prepared by Microsoft, Printed 8/18/2015 HOMCAD®9.10 s/n 06611 0 2010 HydroM Software Solutions LLC Existing Condition Watershed Analysis - Clark Avenue, Salem MA existing-submittal Prepared by Microsoft Printed 8/18/2015 HydroCAD®9'10 s/h 06611 @2010 HydroCAD Software Solutions LLC Page 2 Area Listing (all nodes) ' Area CN Description ' (sq-ft) (subcatchment-numbers) 766,991 70 Woods, Good, HSG C (111S, 1365, 137S, 138S, 140S) 7,317 74 >75% Grass cover, Good, HSG C (142S) , 74,137 81 1/3 acre lots, 30% imp, HSG C (142S, 143S) 24,065 98 Paved parking, HSG C (142S) 872,510 TOTAL AREA ' t 1 Existing Condition Watershed Analysis - Clark Avenue, Salem MA existing-submittal Prepared by Microsoft Printed,.8/18/2015 .HydroCAD®9.10 s/n 06611 ©2010 HvdroCAD Sditvware Solutions LLC Paoe 3 Soil Listing (all nodes) ' Area Soil Subcatchment (sq-ft) Group Numbers 0 HSG A 0 HSG B 872,510 HSG C 111S, 136S, 137S, 138S, 140S, 142S, 143S 0 HSG D 0 Other 872;510 TOTALAREA 1 1 ' 1 - 1 Existing Condition Watershed Analysis- Clark Avenue, Salem MA existing-submittal Type 111 24-hr 2 yr Rainfall=3.10" Prepared by Microsoft Printed 8/18/2015 HydroCAD®9 10 s/n 06611 ©2010 HydroCAD Software Solutions LLC Page 4 Time span=0.00-40.00 hrs, dt=0.05 hrs, 801 points x 3 ' Runoff by SCS TR-20 method, UH=SCS Reach routing by Dyn-Stor-Ind method - Pond routing by Dynstor-Ind method , Subcatohment 111S: EX-1 Runoff Area=318,326 sf 0.00% Impervious Runoff Depth--0.77" Flow Length=430' Tc=13.4 min CN=70 Runoff=4.53 ds 20,440 d Subcatchment 136S: EX-4 Runoff Area=49,366 sf 0.00% Impervious Runoff Depth=0.77" Flow Length=420' Tc=14.2 min CN=70 Runoff=0.69 ds 3,170 d Subcatchment 137S:.EX-2 Runoff Area=127,758 sf 0.00% Impervious Runoff Depth=0.77" , Flow Length=475' Tc=15.6 min CN=70 Runoff=1.71 ds 8,203 d Subcatchment 138S: EX-3 Runoff Area=221,679 sf 0.00% Impervious Runoff Depth=0.77" ' Flow Length=470' Tc=11.9 min CN=70 Runoff=3.27 ds 14,234 d Subcatchment 14OS: EX-5 Runoff Area=49,862 sf 0.00% Impervious Runoff Depth=0.77" ' Flow Length=560' Tc=12.3 min CN=70 Runoff=0.73 ds 3,202 d Subcatchment 142S: EX-RES 1 RunoffArea=93,234 sf 45.71% Impervious Runoff Depth=1.67" ' Flow Length=300' Tc=5.0 min CN=85 Runoff=4.20 ds 12,995 d Subcatchment 143S: EX-RES 2 Runoff Area=12,285 sf 30.00% Impervious Runoff Depth=1.39" t Flow Length=105' Tc=5.0 min CN=81 Runoff=0.46 ds 1,424d Unk 109L: Total Surface Runoff discharging from project area Inflow=12.10 ds 57,296d Primary=12.10 ds 57,296d ' Unk 128L: Runoff towards existing wetlands to the north Inflow--4.78 ds 21,864 d Primary--4.78 ds 21,864 d ' Unk 13OL: Runoff towards Isolated Wetland "B"series Inflow--0.69 ds 3,170 d Primary--0.69 ds 3,170 d Unk 132L: Runoff Into existing catch basins on Clark Avenue Inflow--5.09 cfs 21,199 d Primary--5.09 cis 21,199 d Unk 139L: Runoff towards existing wetlands to the south Inflow--7.62 ds 35,433 d ' Primary--7.62 ds 35,433 d Unk 141L: Runoff towards Isolated Wetland "C"series Inflow--0.73 ds 3,202 d Primary--0.73 ds 3,202 d Total Runoff Area=872,510 sf Runoff Volume=63,668 of Average Runoff Depth =0.88" ' 94.69% Pervious 826,204 sf 5.31%Impervious =46,306 sf 1 i Existing Condition Watershed Analysis - Clark Avenue, Salem MA existing-submittal Type 111 24-hr 2 yr Rainfall=3.10" Prepared by Microsoft Printed 8/18/2015 HydroCAD®9.10 s/n 06611 @2010 HydroCAD Software Solutions LLC Page 5 ' Summary for Subcatchment 111S: EX-1 . iRunoff = 4.53 cfs @ 12.21 hrs, Volume= 20,440 cf, Depth= 0.77" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs iType III 24-hr 2 yr Rainfall=3.10" Area (sf) CN Description i 318,326 70 Woods, Good; HSG C 318,326 100.00% Pervious Area Tc Length Slope Velocity Capacity Description i (min) (feet) (ft/(t) (ft/sec) (cfs) 12.5 100 0.0800 0.13 Sheet Flow, Woods: Light underbrush n= 0.400 P2= 3.10" i 0.9 330 0.1500 6.24 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 13.4 430 Total iSubcatchment 111S: EX-1 Hydrograph 5 R =31 1 .. . 3 . . s . , . ; ;t�rigff >Dli�m � 2044U�Gf; € ' ? #f QOPth►=O TT' LL 2 , ht4 : wno _Flov�iGengt , -3�'� - i 134.4, "n riin : CN OFi i 0 1 2 3 4 5 6""'7 8 9 101112131415161718192021222324252627,28293031323334353837383940 4 nnw (hours) 1 1 1 Existing Condition.Watershed Analysis - Clark Avenue, Salem MA existing-submittal Type Ill 24-hr 2 yr Rainfall=3.10" Prepared by Microsoft Printed 8/18/2015 HydroCAD®910 s/n 06611 ©2010 HydroCAD Software Solutions LLC Page 6 Summary for Subcatchment 136S: EC-4 Runoff = 0.69 cfs @ 12.22 hrs, Volume= 3,170 cf, Depth= 0.77 Runoff by.SCS TR-20 method, UH=SCS, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs Type III 24-hr 2 yr Rainfall=3.10" Area(so CN Description 49,366 70 Woods Good, HSG C 49,366 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (f 1ft) (ft/sec) (cfs) 12.5 100 0.0800 0.13 Sheet Flory, Woods: Light underbrush n=0.400 P2= 3.10" 0.4 100 0.0800 4.55 Shallow Concentrated Flow, ' Unpaved Kv= 16.1 fps 1.3 220 0.0300 2.79 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 14.2 420 Total Subcatchment 136S: EX-4 Hydrograph ;...: Fm-Run-o-6 c..1 ueort.• . 0.65. T:y�� III"���1' 2yri.. o. - ; .,.. ... Etalitifll10" .. - k�ti�f Arlea*49 '366 -sf .. 0.5 _ o. - stun ,f VoY ryie=$;170: Cf - - : ; : .. . 0.4 w tjrioff 0'0000-7 LL 0- ..;.._..;..j... ..�--- - - - -- : i i QViI Ltl;���tz?I201 0 0.2 �}'n . . . . . . . : - - - - s- 0 "1.2 3 4 6 6 7 8 910111213141516171819202122232425262728293031323334353637383940 ' 71m (hour.) I I 1 Existing Condition Watershed Analysis - Clark Avenue, Salem MA existing-submittal Type ///24-hr 2 yr Rainfa//=3.10" Prepared by Microsoft Printed 8/18%2015 HydroCAD®9.10 s/n 06611 @ 2010 HydroCAD Software Solutions LLC Pace 7 " 1 Summary for Subcatchment 137S: EX-2 Runoff = 1.71 cfs @ 12.25 hrs, Volume= 8,203 cf. Depth=, 0.77" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs Type III 24-fir 2 yr Rainfall=3.10" 1 Area (so CN Description 127,758 70 Woods, Good HSG C 1 127,758 100.00% Pervious Area Tc Length Slope Velocity Capacity Description 1 (min) (feet) (ft/ft) (ft/sec) (cfs) 14.1 100 0.0600 0.12 Sheet Flow, Woods: Light underbrush n= 0.400 P2= 3.10" 0.3 90 0.1300 5.80 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 1.2 285 0.0600 3.94 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 1 15.6 475 Total Subcatchment 137S: EX-2 1 Hydrograph T. 1:11:24-hr 2'y' r: Rainfall=110"' 1 ! Rt�n0ffdrea= z7589f` = - - - -- Qf R4 07 tal� O�f ��. 4 F16W :;L dh th=475" 1 tc=15. min: 1 CNS= o 1 0 0 1 2 3 4 5 6 7 8 9 10 1112 13 14 15 16 17 18 19 20 2122 23 24 25 26 27 28 29 30 3132 33 34 35 36 37 38 39 40 71me (hours) 1 1 1 &isting Condition Watershed Analysis - Clark Avenue, Salem MA existing-submittal Type Ill 24-hr 2 yr Rainfall=3.10" ' Prepared by Microsoft Printed 8/18/2015 HydroCAD®9 10 s/n 06611 ©2010 HydroCAD Software'Solutions LLC Page 8 Summary for Subcatchment 138S: EX-3 ' Runoff = 3.27 cfs @ 12.19 hrs, Volume= 14,234 cf, Depth= 0.77" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs Type III 24-hr 2 yr Rainfall=3.10" ' Area (so CN Description 221,679 . 70 Woods Good HSG C ' 221,679 100.00% Pervious Area Tc Length Slope Velocity Capacity, Description (min) (feet) (ft/ft) (ft/sec) (cfs) ' 10.7 100 0.1200 0.16 Sheet Flow, Woods: Light underbrush n= 0.400 P2= 3.10" 0.8 275 0.1300 5.80 Shallow Concentrated Flow, ' Unpaved Kv= 16.1 fps 0.4 95 0.0500 3.60 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps ' 11.9 470 Total. Subcatchment 138S: EX-3 ' Hydrograph �av� A Runoff '..f — - -=- .. Y.00 1, 4-hr-2 �r�.. 3 Raiffallz3i1Q R6fio' ff Ar., ac221 6i79!sf .o € . . . _ . .. . �Ruh6fUth« 0:77 F16dr dth vifC =470" ' GN=7b . +0 1 2 3' 4 5 6.7 8 9 10111213141516171819202122 232425262728293031323334353637383940 Time (hours) 1 t Existing Condition Watershed Analysis - Clark Avenue, Salem MA existing-submittal Type 111 24-hr 2 yr Rainfall=3.10" Prepared by Microsoft Printed 8/18/2015 HydroCAD®9.10 s/n 06611 @2010 HydroCAD Software Solutions LLC Page 9 ' Summary for Subcatchment 14OS: EX-5 Runoff = 0.73 cfs @ .12.20 hrs, Volume= 3,202 cf, Depth= 0.77" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs Type III 24-hr 2 yr Rainfall=3.10" Area (sf) CN Description 49,862 70 Woods, Good HSG C 49,862 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (f/ft) (ft/sec) (cfs) 10.0 100 0.1400 0.17 Sheet Flow, Woods: Light underbrush n= 0.400 P2= 3.10" 0.3 100 0.1400 6.02 Shallow Concentrated Flow, ' Unpaved Kv= 16.1 fps 2.0 360 0.0360 3.05 Shallow Concentrated Flow, 12.3 560 Total Unpaved Kv= 16.1 fps 1 Subcatchment 14OS: EX-5 Hydrograph 0.7 ■ --------- 0.7. -. YT AMER 0.65 -340- U.6 • . . 0.55 • --<--:R�r�of.!f'Area. 49 '86�2 5 MY . ' ? VoILM - z0 . i 0.4 LL 0.35- . . ........__.... . .. _ 0.3 0.2 . . . . . 0.1 - ! - 0.1 . 0 1 2 3 4 6 8 7 8 910111213141516171819202172232425262-728293031323334353637383940 Time (hours) Clark Avenue, Salem MA Existing Condition Watershed Analysis- existing-submittal Type Ill 24-hr 2 yr Rainfall=3.10" ' Prepared by Microsoft Printed 8/18/2015 HydroCAD®910 s/n 06611 ©2010 HydroCAD Software Solutions LLC Page 10 Summary for Subcatchment 142S: EX-RES 1 ' [49] Hint: Tc<2dt may require smaller dt 1 Runoff = 4.20 cfs @ 12.08 hrs, Volume= 12,995 cf, Depth= 1.67" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs ' Type III 24-hr 2 yr Rainfall=3.10" ! Area (so CN Description 61,852 81 1/3 acre lots, 30% imp, HSG C 24,065 98 Paved parking, HSG C 7,317 74 >75% Grass cover, Good, HSG C ' 93,234 85 Weighted Average 50,613 54.29% Pervious Area 42,621 45.71% Impervious Area ' Tc Length Slope Velocity Capacity Description (min) (feet) (fti t) (ft/sec) (cfs) 3.5 50 0.0700 0.24 Sheet Flow, ' Grass: Short n= 0.150 . P2= 3.10" 0.3 100 0.1000 5.09 Shallow Concentrated Flow, . i Unpaved Kv= 16.1 fps , 1.2 150 0.0100 2.03 Shallow Concentrated Flow, Paved Kv= 20.3 fps 5.0 300 Total ' 1 1 1 1 1 Existing Condition Watershed Analysis - Clark Avenue, Salem MA existing-submittal Type 11124-hr 2 yr Rainfall=3.107 Prepared by Microsoft Printed :8/18/2015 HydroCAD®9.10 s/n 06611 ©2010 HydroCAD Software Solutions LLC Page 11 ' Subcatchment 142S: EX-RES 1 Hydrograph T vi ISOrb Rain '` . - off=Aie�a!-. X34' Rin ffio'Itmerh2995cf LL 2 . : h^3 0" f`Iov�r�Lendt� 0 1 -�.0 niih. ....... 1 : : 0 1 2 3 4 5 6 7 8 9 10 1112 13 14 15 16 17 18 19 20 2122 23 24 25 26 27 28 29 30 3132 33 34 35 36 37 38 39 40 ' Time (bourn) i Existing Condition Watershed Analysis- Clark Avenue, Salem MA existing-submittal Type ///24-hr 2 yr Rainfall=3.10" Prepared by Microsoft Printed 8/18/2015 HydroCAM 9 10 s/n 06611 @2010 HydroCAD Software Solutions LLC Page 12 Summary for Subcatchment 143S: EX-RES 2 i [49] Hint: Tc<2dt may require smaller dt ' Runoff = 0.48 cfs @ 12.08 hrs. Volume= 1,424 cf, Depth= 1.39" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs i Type III 24-hr 2 yr Rainfall=3.10" Area (so CN Description , 12,285 81 1/3 acre lots, 30% imp, HSG C 8,600 70.00% Pervious Area 3,686 30.00% Impervious Area i Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) i 4.3 50 0.0400 0.19 Sheet Flow, Grass: Short n=0.150 P2= 3.10" 0.4 55 0.0200 2.28 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 4.7 105 Total, Increased to minimum Tc=5.0 min Subcatchment 143S: EX-RES 2 i Hydrograph ....j , . . 0.5 Q0 ftloffl 0.48 •. •-.:..•-.. 0.44 : ' ..... yr;. 0.42 _ _ ...: 0.4 '---••-'--- '-- -- i - - - - --stn--.- --:--'- 0.36 ..:._:...:..:.. ..:_:... ..:.. Whd f AA 285 - 0.34 :_. ..: -:- -----' r-- . : : :.. ..:.. ..:... .. ..:... R 0.32 :....._:_:..... ......... 0.3 ° - - ° - -' lEf Xao utile= F------- 42- ........... 4 Cf 0.28 '-'- = - . -- ;- .;. t....-- _ 024 13tans 10d th 1:`30- : : ; C 0.22 - - � - -- - - . 0.16 . ..... .............................. . . o.1a ..._ .. _; . 0.1Z ;.. .. .. ...... CN J4-- 0. . • -- i 0.04 0.02 - - _ 0-'1 2 3' 4 5 6 7 8 9 10 1112 13 14 15 16 17 18 19 20 2122 23 24 26 26 27 28 29 30 3132 33 34 35 36 37 38 39 40 Time (hours) 1 1• Existing Condition Watershed Analysis - Clark Avenue, Salem MA existing-submittal Type Ill 24-hr 2 yr Rainfall=3.10" Prepared by Microsoft Printed 8/18/2015 HydroCA1)@ 9.10 s/n 06611 ©2010 HvdroCAD Software Solutions LLC Page 13 ' Summary for Link 1091-: Total Surface Runoff discharging from project area . Inflow Area = 773,282 sf, 5.99% Impervious, Inflow Depth = 0.89" for 2 yr event Inflow 12.10 cfs @ 12.18 hrs, Volume= 57,296 cf Primary 12.10 cfs @ 12.18 hrs, Volume= 57,296 cf, Atten=0%, Lag= 0.0 min ' Primary outflow= Inflow, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs Link 109L: Total Surface Runoff discharging from project area ' Hydrograph Fe Infiow . . . . . . i-104M . . . . . . . . . , fid -fit` � � =7712-82-i� . . . . . . . . . . i i i i i - - -- --- - - -- -- -- - - - ; - - - - - . 1 0 1 9-Y 4 5 6 7 8 8 10111213141516171819202122232425262728293031323334$53637383940 Time (hours) I i 1 i t Existing Condition Watershed Analysis - Clark Avenue, Salem MA existing-submittal Type 111 24-hr 2 yr Rainfall=3.10" Prepared by Microsoft Printed 8/18/2015 HydroCAD®9.10 s/n 06611 @2010 HydroCAD Software Solutions LLC Page 14 Summary for Link 128L: Runoff towards existing wetlands to the north ' Inflow Area = 330,611 sf, 1.11% Impervious, InTow Depth = 0.79" for 2 yr event ' Inflow = 4.78 cfs @ 12.21 hrs, Volume= 21,864 of Primary = 4.78 cfs @ 12.21 hrs,. Volume= 21,864 cf, Atten= 0%, Lag= 0.0 min Primary outflow= Inflow, Time Span= 0.00-40.00 hrs, dt=0.05 hrs Link 1281-: Runoff towards existing wetlands to the north Hydrograph - -- --�--i-?--�- - - - - -- -- -- - - -- -- -- - .i ©Primary 5 : . . . : . 'k cM, f�Qtf Ares=33Q6115 4 3 . : . LL .2 1 0- 0 1 2 3 4 5 6 7 8 9 101112131415 161718 19202122232425262728293031323334353637383940 Time (Mwa) i , Existing Condition Watershed Analysis - Clark Avenue, Salem MA existing-submittal Type N 2¢hr.2 yr.Rainfal1=3.10". Prepared by Microsoft Printed 8/18/2015 HydroCAD®9.10 s/n 06611 @2010 HydroCAD Software Solutions LLC Page 15 ' Summary for Link 130L: Runoff towards Isolated Wetland 'B" series ! ' Inflow Area = 49,366 sf, 0.00% Impervious, Inflow Depth = 0.77" for 2 yr event Inflow 0.69 cfs @ 12.22 hrs, Volume= 3,170 cf Primary = 0.69 cfs @ 12.22 hrs, Volume= 3,170 cf, Atten= 0%, Lag= 0.0 min Primary outflow= Inflow, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs Link 130L: Runoff towards Isolated Wetland 'B" series ' Hydrograph - - . . : . . . . . . . . . . . . . . . . . - { . , 0.75 :Deva.: - - - _• r - __ D Primary0.7 0 th ifib Ot 9.55 ........:..:..:.. .:..:..:..:..;..:.::..: -� 0.45 ' . ..{..:.•:._;.-{ .......•,..{'-t------{-- - - . . - - 0 LL I . ; 9 -.........__ - - __ .. - .....- 9.25 ..:..:...:.. ......... ..... ' 0.95 -• .'. /.' : 0 1 2 3 4 5 6 7 8 910111213141516171819202122232425282728283031323334353637383940 T{me (hou{s) I 1 . , 1 1 Existing Condition Watershed Analysis - Clark Avenue, Salem MA existing-submittal Type Ill 24-hr 2 yr Rainfall=3.10" ' Prepared by Microsoft Printed 8/18/2015 HydroCAD89 10 s/n 06611 O 2010 HydroCAD Software Solutions LLC Page 16 Summary.for Link 132L: Runoff into existing catch basins on Clark Avenue ' Inflow Area = 220,992 sf, 19.29% Impervious, Inflow Depth = 1.15" for 2 yr event Inflow = 5.09 cfs @ 12.09 hrs, Volume= 21,199 cf Primary 5.09 cfs @ 12.09 hrs, Volume= 21,199 cf, Atten= 0%, Lag= 0.0 min Primary outflow= Inflow, Time Span= 0.00-40.00 hrs, dt`— 0.05 hrs ' Link 132L: Runoff into existing catch basins on Clark Avenue Hydrograph , i ��sro nf� M'Are0=? 4 '99' • Tse ' 5 . . . , . . . . . . . ®�rimery 4 .- 3 2 ; 1 1 0 0 1 2 3 4 5 6 7 8 910111213141516171819202122232425262728293031323334353637383940 Time (hours) Existing Condition Watershed Analysis - Clark Avenue, Salem MA ' existing-submittal Type Ill 24-hr 2 yr Rainfall=3.10" Prepared by Microsoft Printed 8/18/2015 . HydroCAD®9.10 s/n 06611 @2010 HydroCAD Software Solutions LLC PaQe 17 Summary for Link 139L: Runoff towards existing wetlands to the south 1 Inflow Area = 442,671 sf, 9.63% Impervious, Inflow Depth = 0.96" for 2 yr event Inflow 7.62 cfs @ 12.13 hrs, Volume= 35,433 cf Primary = 7.62 cis @ 12.13 hrs, Volume= 35,433 cf. Atten= 0%, Lag= 0.0 min Primary outflow= Inflow, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs Link 139L: Runoff towards existing wetlands to the south Hydrograph 8 . • Jaz .� � i � �-1 B{Primary } , ., .--;- ;--- -->--,..i.--;--;.. --- bow 0 4 3 2 - .......... 0- 0 0 1 2 3 4 5 6 7 8 9 10111213141516171819202122232425262728293031323334353637383940 Time (hours) . Existing Condition Watershed Analysis - Clark Avenue, Salem MA existing-submittal Type ill 24-hr 2 yr Rainfall=3.10" Prepared by Microsoft Printed 8/18/2015 HydroCAD®9.10 s/n 06611 @2010 HydroCAD Software Solutions LLC Page 18 Summary for Link 141 L: Runoff towards Isolated Wetland "C"series ' Inflow Area = 49,862 sf, 0.00% Impervious, Inflow Depth = 0.77" for 2 yr event Inflow = 0.73 cfs @ 12.20 hrs, Volume= 3,202 cf Primary = 0.73 cfs @ 12.20 hrs, Volume= 3,202 cf, Atten= 0%, Lag= 0.0 min Primary outflow= Inflow, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs , Link 141 L: Runoff towards Isolated Wetland "C"series Hydrograph ------------------------------------ __ - - - _-- - _ __--- -- ■Inflow 0.75 . : 37 0.7 . . . . . . . . . . T ------------ � -�-- 0 Primary 0. 9.55 . 0. >.. . 0.4 LL 0.35 .. 9.3 . ..�..,..�.....1..�...•,..F._;.. i..;.. .F._1..;._;..l..a..;._;_.1..�.-�..;..{..i-"�..f..l..;._�._F..{ ;.. ._ l_. 025 . 02 0.15 -r- : 0.1 IN 11111 0.05 ' Jill I .� 0 1 '2 3 4 5 6 7 8 91011121314151877181920272223242526272829303i32333435363738394o Time (hour) 1 1 Existing Condition Watershed Analysis -Clark Avenue, Salem MA existing-submittal Type 11124-hr 10 yr Rainfall=4.50" Prepared by Microsoft Printed 8/18/2015 HydroCAD®9.10 s/n 06611 ©2010 HydroCAD Software Solutions LLC Page 1 ' Time span=0.00-40.00 hrs, dt=0.05 hrs, 801 points x 3 Runoff by SCS TR-20 method, UH=SCS Reach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method ' Subcatchment 111S: EX-1 Runoff Area=318,326 sf 0.00%Impervious Runoff Depth=1.67" Flow Length=430' Tc=13.4 min CN=70 Runoff=10.85 cfs 44,400 cf Subcatchment 136S: EX-4 Runoff Area=49,366 sf 0.00% Impervious Runoff Depth=1.67" Flow Length=420' Tc=14.2 min CN=70 Runoff=1.65 cfs 6,886 cf ' Subcatchment 137S: EX-2 Runoff Area=127,758 sf 0.00% Impervious Runoff Depth=1.67" Flow Length=475' Tc=15.6 min CN=70 Runoff=4.10 cfs 17,820 cf ' Subcatchment 138S: EX.3 Runoff Area=221,679 sf 0.00% Impervious Runoff Depth=1.67" Flow Length=470' Tc=11.9 min CN=70 Runoff=7.90 ds 30,920 cf Subcatchment 14OS: EX-5 Runoff Area=49,862 sf 0.00% Impervious Runoff Depth=1.67" Flow Length=560' Tc=12.3 min CN=70 Runoff=1.74 ds 6,955 d Subcatchment 142S: EX-RES 1 RunoffArea=93,234 sf 45.71% Impervious Runoff Depth=2.91" Flow Length=300' TC=5.0 min CN=85 Runoff=7.30 ds 22,602 cf Subcatchment 143S: EX-RES 2 Runoff Area--12,285 sf 30.00% Impervious Runoff Depth=2.55" Flow Length=105' Tc=5.0 min CN=81 Runoff=0.84 cis 2,609 cf Unk 109L: Total Surface Runoff discharging from project area Inflow=27.50 cfs 118,350cf Primary=27.50 cfs 118,350 cf Unk 128L: Runoff towards existing wetlands to the north Inflow=11.32 cfs 47,008cf ' Primary=11.32 cfs 47,008cf Unk 13OL: Runoff towards Isolated Wetland"B"series Inflow-1.65 ds 6,886 cf Primary--1.65 ds 6,886 cf Unk 132L: Runoff Into existing catch basins on Clark Avenue Inflow--9.74 ds 40,422 cf Primary--9.74 ds 40,422 cf Unk 139L: Runoff towards existing wetlands to the south Inflow-16.51 cis 71,342 cf Primary--1 6.51 ds 71,342 cf Unk 141 L: Runoff towards Isolated Wetland "C"series Inflow--1.74 ds 6,955 d Primary--1.74 ds 6,955 d ' Total Runoff Area=872,510 sf Runoff Volume= 132,190 cf Average Runoff Depth = 1.82" 94.69%Pervious=826,204 sf. 5.31%Impervious=46,306 sf t alsting Condition Watershed Analysis - Clark Avenue, Salem MA existing-submittal Type ///24-hr 100 yrRainfa&6.50" Prepared by Microsoft Printed 8/18/2015 HydroCAD®9:10 s/n 06611 O 2010 HydroCAD Software Solutions LLC Pape 2 Time span=0.00-40.00 hrs, dt=0.05 hrs, 801 points x 3 Runoff by SCS TR-20 method, UH=SCS Reach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method Subcatchment 111S: EX-1 •Runoff Area=318,326 sf 0.00% Impervious Runoff Depth=3.21" Flow Length=430' Tc=13.4 min CN=70 Runoff=21.43 ds 85,075 cf Subcatchment 136S: EX-4 Runoff Area=49,366 sf 0.00% Impervious Runoff Depth=3.21" ' Flow.Length=420' Tc=14.2 min CN=70 Runoff=3.26 cfs 13,193 cf Subcatchment 137S: EX-2 Runoff Area=127,758 sf 0.00% Impervious Runoff Depth=3.21" ' Flow Length=475' Tc=15.6 min CN=70 Runoff=8.16 ds 34,144 d Subcatchment 138S: EX-3 Runoff Area=221,679 sf 0.00% Impervious Runoff Depth=321" ' Flow Length=470' Tc=11.9 min CN=70 Runoff=15.61 ds 59,245d Subcatchment 14OS: EX-5 Runoff Area=49,862 sf 0.000/9 Impervious Runoff Depth=3.21" ' Flow Length=560' Tc=12.3 min CN=70. Runoff=3.47 ds 13,321 d Subcatchment 142S: EX-RES 1 Runoff Area=93,234 sf 45.71% Impervious Runoff Depth=4.78' ' Flow Length=300' Tc=5.0 min CN=85 Runoff=11.77 ds 37,107 d Subcatchment 143S: EX-RES 2 Runoff Area=12,285 sf 30.00% Impervious Runoff Depth=4.34' Flow Length=105' Tc=5.0 min CN=81 Runoff=1.43 ds 4,445 d Link 109L: Total Surface Runoff discharging from project area Inflow-52.76 ds 220,017 d Primary--52.76 ds .220,017 d ' Link 128L: Runoff towards existing wetlands to the north Inflow--22.23 cis 89,520 d Primary--22.23 cis 89,520 d ' Link 130L: Runoff towards Isolated Wetland "B"series Inflow--3.26 ds 13,193 d Primary--3.26 cis 13,193 d Link 132L: Runoff Into existing catch basins on Clark Avenue Inflow=16.95 cis 71,251 d Primary--16.95 ds 71,251 d Link 139L: Runoff towards existing wetlands to the south Inflow--30.96 ds 130,497 d ' Primary--30-96 ds 130,497 d Link 141L: Runoff towards Isolated Wetland "C"series Inflow--3.47 ds 13,326 d Primary--3.47 ds 13,326 d Total Runoff Area=872,510 sf Runoff Volume=246,536 cf Average Runoff Depth =3.39" , 94.69%Pervious=826,204 sf 5.31%Impervious=46,306 sf 1 1 i 1 1 1 1 1 1 Prop osed Condition 1 Watershed Analysis 1 � 1 1 ' 1 � 1 , 1 � 1 ! 1 ' 1 i 1 wuso.ol� au�(i.�u,r --P� 1515 /1505 ' o,acsomr ggvu irx wwrp� pate else f t KT . td95 i3Y5 ' F141E41\ /Eza fee] 1435 \\V \\p a oris. m®f.asRr arm,fee, w.rn .moo wR .mm M1eI� aco I< LT t.. t%�8>\ TW eJ1 1441 ' 11 8 v tllral t� EWIR k }1�hbed,� 1 . / Y 150.5 113011 4 1365 ;�. �� � NKBV AIR WNbsO b:/re ocXX Q ¢\ W6eTv1� i , WMlIa] 1 p�14N1\ / i � ut• 'v 1e05 9� /c.. on®oA<i Wan4nmlm., fxalllua.wl `0.5,5 1535 . wr.eear RO®TAXI ' SubCdt Reach Otte Clot Routing Diagram for proposed-SUBMITTAL-11 s . raPrepared by Microsoft, Printed g/18/2015 HydroCAD910.00-15 stn 06611 ®2015 HydroCAD Software Solutions LLC i 1 Proposed Condition Watershed Analysis - Revised 8/31/2015- The Woodlands - Salem MA 1 proposed-SU BMITTAL_R Prepared by Microsoft Printed 9/18/2015 HydrOCADO 10.00-15 s/n 06611 ©2015 HydroCAD Software Solutions LLC Page 2 ' Area Listing (all nodes) Area CN Description ' (sq-ft) (subcatchment-numbers) 74,537 81 1/3 acre lots, 30% imp, HSG C (138S, 149S, 155S) 234,394 74 >75% Grass cover, Good, HSG C (80S, 81S, 1115, 136S, 137S, 138S, 142S, 1 1435, 144S, 145S, 146S, 147S, 149S, 150S, 151S, 152S, 153S, 154S, 156S) 94,546 98 Paved parking, HSG C (805, 815, 144S, 145S, 1465, 147S, 149S, 150S, 1525, 1 153S, 154S) 4,840 91 Rip Rap, HSG C '(156S) 4,490 91 Rip rap slope, HSG C (111 S) 1,125 98 Roofs, HSG C (148S) , 2,382 98 Unconnected pavement, HSG C (136S, 137S) 37,500 98 Unconnected roofs; HSG C (80S, 111 S, 136S, 137S, 138S, 142S, 143S, 1445, , 145S, 146S, 147S, 150S, 151S, 152S, 153S, 154S, 156S) 418,696 70 Woods, Good, HSG C (81 S. 111S. 136S, 137S, 138S, 140S, 143S, 149S, 151S, 155S) 1 872,510 77 TOTAL AREA 1 1 . 1 1 1 r i 1 1 1 Proposed Condition Watershed Analysis - Revised 8/31/2015- The Woodlands - Salem MA proposed-SUBMITTAL_R Prepared by Microsoft Printed 9/18/2015 HydroCAD® 10.00-15 s/n 06611 @2015 HydroCAD Software Solutions LLC Page 3 Soil Listing (all nodes) ' Area Soil Subcatchment (sq-ft) Group Numbers 0 HSG A t 0 HSG B 872,510 HSG C 80S, 81S, 111S, 136S, 1375, 138S, 140S, 142S, 143S, 144S, 1455, 146S, 147S, 1485, 149S, 150S, 151S, 152S, 153S, 154S, 155S, 156S ' 0 HSG D 0 Other 872,510 TOTAL AREA 1 t 1 Proposed Condition Watershed Analysis - Revised 8/31/2015-The Woodlands - Salem MA ' i proposed-SUBMITTAL_R Prepared by Microsoft Printed 9/18/2015 HydroCAD®10.00-15 s/n 06611 ©2015 HydroCAD Software Solutions LLC Page 4 ' Pipe Listing (all nodes) Line# Node In-Invert Out-Invert Length Slope n Diam/Width Height Inside-Fill , Number (feet) (feet) (feet) (ft/ft) (inches) (inches) (inches) 1 142P 131.50 129.75 175.0 0.0100 0.010 12.0 0.0 0.0 ' 2 143P 127.50 127.00 16.0 0.0313 0.010 12.0 0.0 0.0 , 3 144P 114.50 114.00 13.0 0.0385 0.010 12.0 0.0 0.0 4 152P 113.50 113.00 10.0 0.0500 0.010 12.0 0.0 0.0 ' i i 1 ' Proposed Condition Watershed Analysis - Revised 8/31/2015-The Woodlands - Salem MA proposed-SUBMITTAL R Type 111 24-hr 2 yr Rainfall=3.10" Prepared by Microsoft Printed 9/18/2015 HydroCAD@ 10.00-15 s/n 06611 @2015 HvdroCAD Software Solutions LLC Page 5 Summary for Subcatchment 80S: PR-CB O+ORT ' [49] Hint: Tc<2dt may require smaller dt Runoff = 0.29 cfs @ 12.07 hrs, Volume= 901 cf, Depth= 2.16" ' Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs Type III 24-hr 2 yr Rainfall=3.10" ' Area (so CN Description 375 98 Unconnected roofs, HSG C 1,515 74 >75% Grass cover, Good, HSG C ' 3,107 98 Paved parking, HSG C 4,997 91 Weighted Average 1,515 30.32% Pervious Area 3,482 69.68% Impervious Area 375 10.77% Unconnected ' Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 3.3 25 0.0200 0.13 Sheet Flow, Grass: Short n= 0.150 P2= 3.10" ' 0.1 15 0.0312 3.59 Shallow Concentrated Flow, Paved Kv= 20.3 fps 0.6 165 0.0500 4.54 Shallow Concentrated Flow, Paved Kv= 20.3 fps 4.0 205 Total, Increased to minimum Tc = 5.0 min i t Summary for Subcatchment 81 S: PR-CB O+OLT [49] Hint: Tc<2dt may require smaller dt Runoff 0.33 cfs @ 12.08 hrs, Volume= 1,026 cf, Depth= 1.39" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs Type III 24-hr 2 yr Rainfall=3.10" Area (sf) CN Description ' 375 70 Woods, Good, HSG C 3,751 74 >75% Grass cover, Good, HSG C 3,023 98 Paved parking, HSG C ' 1,700 70 Woods, Good, HSG C 8,849 81 Weighted Average 5,826 65.84% Pervious Area ' 3,023 34.16% Impervious Area 1 i Proposed Condition Watershed Analysis - Revised 8/31/2015- The Woodlands - Salem MA proposed-SUBMITTAL_R Type 11124-hr 2 yr Rainfall=3.10" ' Prepared by Microsoft Printed 9/18/2015 HydroCAD®10.00-15 s/n 06611 ©2015 HydroCAD Software Solutions LLC . Page 6 ' Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (f/sec) (cfs) 3.3 25 0.0200 0.13 Sheet Flow, Grass: Short n= 0.150 P2= 3.10" 0.1 15 0.0312 3.59 Shallow Concentrated Flow, Paved Kv= 20.3 fps ' 0.6 160 0.0500 4.54 Shallow Concentrated Flow, Paved Kv= 20.3 fps 4.0 200 Total, Increased to minimum Tc = 5.0 min ' Summary for Subcatchment 111 S: EX-1 R Runoff = 3.15 cfs @ 12.21 hrs, Volume= 13,751 cf, Depth=-0.87" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs Type 11124-hr 2 yr Rainfall=3.10" Area (so CN Description 141,864 70 Woods, Good, HSG C ' 37,700 74 >75% Grass cover, Good, HSG C 6,000 98 Unconnected roofs, HSG C ' 4,490 91 Rip rap slope, HSG C 190,054 72 Weighted Average 184,054 96.84% Pervious Area 6,000 3.16% Impervious Area 6,000 100.00% Unconnected ' Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 12.5 100 0.0800 0.13 Sheet Flow, Woods: Light underbrush n= 0.400 P2= 3.10" 0.4 100 0.0800 4.55 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 0.7 275 0.1500 6.24 Shallow Concentrated Flow, Unpaved Kv= 16.1_fps ' 13.6475 Total Summary for Subcatchment 136S: EX-411 ' Runoff = 1.15 cfs @ 12.22 hrs, Volume= 5,113 cf, Depth= 0.87" i Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs ' Type III 24-hr 2 yr Rainfall=3.10" Proposed Condition Watershed Analysis - Revised 8/31/2015-The Woodlands - Salem MA ' proposed-SUBMITTAL_R Type 11124-hr 2 yr Rainfall=3.10" Prepared by Microsoft Printed 9/18/2015 H_ydroCAD®10.00-15 s/n 06611 @2015 HydroCAD Software Solutions LLC Page 7 Area (so CN Description 51,513 70 Woods, Good, HSG C ' 2,250 98 Unconnected roofs, HSG C 1,142 98 Unconnected pavement, HSG C 15,763 74 >75% Grass cover, Good, HSG C 70,668 72 Weighted Average 67,276 95.20% Pervious Area 3,392 4.80% Impervious Area 3,392 100.00% Unconnected ' T.c Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) ' 12.5 100 0.0800 0.13 Sheet Flow, Woods: Light underbrush n= 0.400 P2= 3.10" 0.4 100 0.0800 4.55 Shallow Concentrated Flow, 1Unpaved Kv= 16.1 fps 1.3 220 0.0300 2.79 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 14.2 420 Total Summary for Subcatchment 137S: tk2r ' [49] Hint: Tc<2dt may require smaller dt Runoff = 0.36 cfs @ 12.09 hrs, Volume= 1,153 cf, Depth= 1.03" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs Type III 24-hr 2 yr Rainfall=3.10" I '� Area (so CN Adi Description 500 70 Woods, Good, HSG C ' 375 98 Unconnected roofs, HSG C 1,240 98 Unconnected pavement, HSG C 11,363 74 >75% Grass cover, Good, HSG C 13,478 77 75 Weighted Average, UI Adjusted 11,863 88.02% Pervious Area 1,615 11.98% Impervious Area 1,615 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) .(ft/sec) (cfs) ' 3.3 50 0.0800 0.25 Sheet Flow, Grass: Short n= 0.150 P2= 3.10" 0.5 100 0.0400 3.22 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 0.6 95 0.0260 2.60 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 0.1 35 0.1100 5.34 Shallow Concentrated Flow, ' Unpaved Kv= 16.1 fps 4.5 280 Total, Increased to minimum Tc = 5.0 min i Proposed Condition Watershed Analysis - Revised 8/31/2015- The Woodlands - Salem MA , proposed-SUBMIITAL_R Type 111 24-hr 2 yr Rainfall=3.10" Prepared by Microsoft Printed 9/18/2015 HydroCAD®10.00-15 s/n 06611 @2015 HydroCAD Software Solutions LLC Page 8 Summary for Subcatchment 138S: EX-3R Runoff = 2.84 cfs @ 12.24 hrs, Volume= 13,329 cf, Depth= 0.82" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs Type III 24-hr 2 yr Rainfall=3.10" Area (so CN Description 400 81 1/3 acre lots, 30% imp, HSG C ' I 159,236 70 Woods, Good, HSG C i 3,750 98 Unconnected roofs,'HSG C 32,000 74 >75% Grass cover, Good, HSG C 195,386 71 Weighted Average 191,516 98.02% Pervious Area 3,870 1.98% Impervious Area 3,750 96.90% Unconnected i j Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) ' i 14.8 100 0.0530 0.11 Sheet Flow, Woods: Light underbrush n= 0.400 P2= 3.10" 0.5 180 0.1700 6.64 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 0.3 45 0.0200 2.28 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 15.6 325 'Total ' Summary for Subcatchment 14OS: EX-5 (No Change) Runoff = 0.73 cfs @ 12.20 hrs, Volume= 3,202 cf, Depth= 0.77" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs Type III 24-hr 2 yr Rainfall=3.10" Area (so CN Description 49,862 70 Woods, Good, HSG C 49,862 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (f/sec) (cfs) 10.0 100 0.1400 0.17 Sheet Flow, Woods: Light underbrush n= 0.400 P2= 3.10" 0.3 100 0.1400 6.02 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 2.0 360 0.0360 3.05 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 12.3 560 Total 1 Proposed Condition Watershed Analysis - Revised 8/31/2015- The Woodlands - Salem MA ' proposed-SUBMITTAL_R Type 111 24-hr 2 yr Rainfall=3.10" Prepared by Microsoft Printed 9/18/2015 HydroCADO 10.00-15 s/n 06611 @2015 HydroCAD Software Solutions LLC Page 9 ' Summary for Subcatchment 142S: PR- POND 2 [49] Hint: Tc<2dt may require smaller dt Runoff 0.38 cfs @ 12.09 hrs, Volume= 1,237 cf, Depth= 1.03" ' Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs Type III 24-hr 2 yr Rainfall=3.10 ' Area (so CN Description 13,712 74 >75% Grass cover, Good, HSG C 750 98 Unconnected roofs, HSG C ' 14,462 75 Weighted Average 13,712 94.81% Pervious Area 750 5.19% Impervious Area 750 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (f/ft) (f/sec) (cfs) 1 3.5 50 0.0700 0.24 Sheet Flow, Grass: Short n= 0.150 P2= 3.10" 0.1 20 0.0700 4.26 Shallow Concentrated Flow, ' Unpaved Kv= 16.1 fps 0.0 15 0.3300 9.25 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps ' 3.6 85 Total, Increased to minimum Tc = 5.0 min Summary for Subcatchment 143S: PR-POND 1 ' [49] Hint: Tc<2dt may require smaller dt Runoff = 1.14 cfs @ 12.09 hrs, Volume= 3,690 cf, Depth= 1.03" ' Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs Type III 24-hr 2 yr Rainfall=3.10" ' Area (sf) CN Adi Description 4,125 98 Unconnected roofs, HSG C ' 33,998 74 >75% Grass cover, Good, HSG C 5,000 70 Woods, Good HSG C 43,123 76 75 Weighted Average, UI Adjusted ' 38,998 90.43% Pervious Area 4,125 9.57% Impervious Area 4,125 100.00% Unconnected 1 Proposed Condition Watershed Analysis - Revised 8/31/2015-The Woodlands - Salem MA proposed-SUBMITTAL_R Type 11124-hr 2 yr Rainfall=3.10" Prepared by Microsoft Printed 9/18/2015 HydroCAD@ 10.00-15 s/n 06611 @2015 HydroCAD Software Solutions LLC Page 10 Tc Length Slope Velocity Capacity Description ' (min) (feet) (ft/ft) (ft/sec) (cfs) 3.8 50 0.0550 0.22 Sheet Flow, Grass: Short n= 0.150 P2= 3.10" 1.1 170 0.0250 2.55 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps ' 0.1 65 0.3300 9.25 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 5.0 285 Total Summary for Subcatchment 144S: PR-CB 1+65 RT ' [49] Hint: Tc<2dt may require smaller dt ' Runoff = 0.40 cfs @ 12.08 hrs, Volume= 1,256 cf, Depth= 1.91" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs ' Type III 24-hr 2 yr Rainfall=3.10" Area (sf) CN Description 1,125 98 Unconnected roofs, HSG C 3,458 98 Paved parking, HSG C 3,319 74 >75% Grass cover, Good, HSG C ' 7,902, 88 Weighted Average 3,319 42.00% Pervious Area 4,583 58.00% Impervious Area ' 1,125 24.55% Unconnected Tc Length Slope Velocity Capacity Description t (min) (feet) (ft/ft) (ft/sec) (cfs) 3.3 25 0.0200 0.13 Sheet Flow, Grass: Short n= 0.150 P2= 3.10" ' 0.0 10 ,0.0312 3.59 Shallow Concentrated Flow, Paved Kv= 20.3 fps 0.6 165 0.0500 4.54 Shallow Concentrated Flow, Paved Kv= 20.3 fps ' 3.9 200 Total, Increased to minimum Tc = 5.0 min Summary for Subcatchment 145S: PR-CB 3+50LT ' (49] Hint: Tc<2dt may require smaller dt Runoff = 0.87 cfs @ 12.08 hrs, Volume= 2,741 cf, Depth= 1.99" ' Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs ' Type III 24-hr 2 yr Rainfall=3.10" 1 Proposed Condition Watershed Analysis - Revised 8/31/2015-The Woodlands -Salem MA ' proposed-SUBMITTAL_R Type 111 24-hr 2 yr Rainfall=3.10" Prepared by Microsoft Printed 9/18/2015 HydroCAD@ 10.00-15 s/n 06611 @2015 HydroCAD Software Solutions LLC Page 11 ' Area (sf) CN Description 2,625 98 Unconnected roofs, HSG C ' 7,358 98 Paved parking, HSG C 6,539 74 >75% Grass cover, Good, HSG C 16,522 89 Weighted Average 6,539 39.58% Pervious Area 9,983 60.42% Impervious Area 2,625 26.29% Unconnected ' Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 3.6 20 0.0100 0.09 Sheet Flow, ' Grass: Short n= 0.150 P2= 3.10" 0.0 10 0.0312 3.59 Shallow Concentrated Flow, Paved Kv= 20.3 fps ' 1.7 285 0.0200 2.87 Shallow Concentrated Flow, Paved Kv= 20:3 fps 5.3 315 Total ' Summary for Subcatchment 146Ss PR-CB 3+50RT [49] Hint: Tc<2dt may require smaller dt Runoff = 0.77 cfs @ 12.07 hrs, Volume= 2,402 cf, Depth= 2.16" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs Type III 24-hr 2 yr Rainfall=3.10" ' Area (sf) CN Description 2,625 98 Unconnected roofs, HSG C 6,914 98 Paved parking, HSG C 3,775 74 >75% Grass cover, Good, HSG C 13,314 91 Weighted Average 3,775 28.35% Pervious Area 9,539 71.65% Impervious Area ' 2,625 27.52% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 2.9 15 0.0100 0.09 Sheet Flow, Grass: Short n= 0.150 P2= 3.10" ' 0.0 10 0.0312 3.59 Shallow Concentrated Flow, Paved Kv=20.3 fps 1.7 285 0.0200 2.87 Shallow Concentrated Flow, Paved Kv= 20.3 fps 4.6 310 Total, Increased to minimum Tc = 5.0 min Proposed Condition Watershed Analysis - Revised 8/31/2015-The Woodlands - Salem MA proposed-SUBMITTAL_R Type ///24-hr 2 yr Rainfall=3.10" Prepared by Microsoft Printed 9/18/2015 HydroCAD® 10.00-15 s/n 06611 @ 2015 HydroCAD Software Solutions LLC Page 12 Summary for Subcatchment 147S: PR-CB 1+65 LT ' [49] Hint: Tc<2dt may require smaller dt ' Runoff = 0.48 cfs @ 12.07 hrs, Volume= 1,499 cf, Depth= 1.99" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-40.00 hrs, dt= 0.65 hrs ' Type III 24-hr 2 yr Rainfall=3.10" Area (so CN Description 1,500 98 Unconnected roofs, HSG C 4,314 98 Paved parking, HSG C 3,225 74 >75% Grass cover, Good, HSG C ' 9,039 89 Weighted Average 3,225 35.68% Pervious Area 5,814 64.32% Impervious Area ' 1,500 25.80% Unconnected Tc Length Slope Velocity Capacity Description ' (min) (feet) (ft/ft) (f 1sec) (cfs) 3.3 25 0.0200 0.13 Sheet Flow, Grass: Short n= 0.150 P2= 3.10" 0.0 10 0.0312 3.59 Shallow Concentrated Flow, ' Paved Kv= 20.3 fps 0.6 165 0.0500 4.54 Shallow Concentrated Flow, Paved Kv= 20.3 fps 3.9 200 Total, Increased to minimum Tc = 5.0 min Summary for Subcatchment 148S: 3/4 roof area Lot 12 ' [49] Hint: Tc<2dt may require smaller dt Runoff = 0.08 cfs @ 12.07 hrs, Volume= 269 cf, Depth= 2.87" ' Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs , Type III 24-hr 2 yr Rainfall=3.10" Area (sf) CN Description 1,125 98 Roofs, HSG C ' 1,125 100.00% Impervious Area Tc Length Slope Velocity Capacity Description ' (min) (feet) (ft/ft) (ft/sec) (cfs) 1.0 Direct Entry, 1.0 0 Total, Increased to minimum Tc = 5.0 min ' Proposed Condition Watershed Analysis - Revised 8/31/2015- The Woodlands - Salem MA ' proposed-SUBMITTAL_R Type 11124-hr 2 yr Rainfall=3.10" Prepared by Microsoft Printed 9/18/2015 HydroCAD® 10.00-15 s/n 06611 @2015 HydroCAD Software Solutions LLC Page 13 Summary for Subcatchment 149S: EX-RES 1 r ' [49) Hint: Tc<2dt may require smaller dt Runoff = 4.27 cfs @ 12.08 hrs, Volume= 13,219 cf, Depth= 1.67" ' Runoff by SCS TR-20 method, UH=SCS, Weighted-CN;Time Span= 0.00-40.00 hrs, dt= 0.05 hrs Type III 24-hr 2 yr Rainfall=3.10" ' Area (so CN Description 61,852 81 113 acre lots, 30% imp, HSG C 24,065 98 Paved parking, HSG C ' 7,317 74 >75% Grass cover, Good, HSG C 1,606 70 Woods;Good, HSG C 94,840 85 Weighted Average t 52,219 55.06% Pervious Area 42,621 44.94% Impervious Area ' Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (f/sec) (cfs) 3.5 50 0.0700 0.24 Sheet Flow, Grass: Short n= 0.150 P2= 3.10" ' 0.3 100 0.1000 5.09 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 1.2 150 0.0100 2.03 Shallow Concentrated Flow, Paved Kv= 20.3 fps 5.0 300 Total Summary for Subcatchment 15OS: PR-CB Road B Runoff = 1.68 cfs @ 12.10 hrs, Volume= 5,442 cf, Depth= 2.08" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs Type III 24-hr 2 yr Rainfall=3.10" Area (sf) CN Description 3,750 98 Unconnected roofs, HSG C 10,385 74 >75% Grass cover, Good, HSG C ' 17,318 98 Paved parking, HSG C 31,453 90 Weighted Average 10,385 33.02% Pervious Area 21,068 66.98% Impervious Area 3,750 17.80% Unconnected Proposed Condition Watershed Analysis - Revised 8/31/2015- The Woodlands - Salem MA proposed-SUBMITTAL_R Type ///24-hr 2 yr Rainfall,=3.10" Prepared by Microsoft Printed 9/18/2015 HydroCAD®10.00-15 s/n 06611 @2015 HydroCAD Software Solutions LLC Page 14 Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 4.3 35 0.0200 0.14 Sheet Flow, ' Grass: Short n= 0.150 P2= 3.10" 0.0 10 0.0312 3.59 Shallow Concentrated Flow, Paved Kv= 20.3 fps 2.2 270 0.0100 2.03 Shallow Concentrated Flow, Paved Kv= 20.3 fps 6.5 315 Total I ' Summary for Subcatchment 151 S: PR-POND 3 [49] Hint: Tc<2dt may require smaller dt ' Runoff = 0.60 cfs @ 12.09 hrs, Volume= 1,981 cf, Depth= 0.92" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs ' Type III 24-hr 2 yr Rainfall=3.10" Area (sf) CN Adi Description 375 98 Unconnected roofs, HSG C 20,077 74 >75% Grass cover, Good, HSG C , 5,400 70 Woods, Good, HSG C 25,852 74 73 Weighted Average, UI Adjusted 25,477 98.55% Pervious Area 375 1.45% Impervious Area 375 100.00% Unconnected Tc Length Slope Velocity Capacity. Description (min) (feet) (ft/ft) (ft/sec) (cfs) 2.4 50 0.1700 0.34 Sheet Flow, Grass: Short n= 0.150 P2= 3.10" 0.3 115 0.1700 6.64 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 0.0 10 0.3300 9.25 Shallow Concentrated Flow, ' Unpaved Kv= 16.1 fps 2.7 175 Total, Increased to minimum Tc = 5.0 min Summary for Subcatchment 152S: PR-CB 9+50LT , [49] Hint: Tc<2dt may require smaller dt Runoff = 0.82 cfs @ 12.07 hrs, Volume= 2,549 cf, Depth= 2.16" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs ' Type III 24-hr 2 yr Rainfall=3.10" 1 Proposed Condition Watershed Analysis - Revised 8/31/2015-The Woodlands -Salem MA ' proposed-SUBMITTAL_R Type 111 24-hr 2 yr Rainfall=3.10" Prepared by Microsoft Printed 9/18/2015 HydroCAD@ 10.00-15 s/n 06611 @ 2015 HvdroCAD Software Solutions LLC Page 15 tArea (so CN Description 2,625 98 Unconnected roofs, HSG C ' 4,401 74 >75% Grass cover, Good, HSG C 7,107 98 Paved parking, HSG C 14,133 91 Weighted Average ' 4,401 31.14% Pervious Area 9,732 68.86% Impervious Area 2,625 26.97% Unconnected ' Tc Length Slope Velocity Capacity Description (min) (feet) (f/ft) (ft/sec) (cfs) 3.3 25 0.0200 0.13 Sheet Flow, Grass: Short n= 0.150 P2= 3.10" 0.0 10 0.0312 3.59 Shallow Concentrated Flow, Paved Kv= 20.3 fps 1.7 260 0.0160 2.57 Shallow Concentrated Flow, Paved Kv= 20.3 fps 5.0 295 Total ' Summary for Subcatchment 153S: PR-CB 10+84 [49] Hint: Tc<2dt may require smaller dt Runoff = 0.93 cfs @ 12.07 hrs, Volume= 2,931 cf, Depth= 2.26" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs Type III 24-hr 2 yr Rainfall=3.10" ' Area (so CN Description 1,875 98 Unconnected roofs, HSG C 3,834 74 >75% Grass cover, Good, HSG C ' 9,884 98 Paved parking HSG C 15,593 92 Weighted Average 3,834 24.59% Pervious Area 11,759 75.41% Impervious Area 1,875 15.95% Unconnected Tc Length Slope Velocity Capacity Description ' (min) (feet) (ft/ft) (f/sec) (cfs) .3.3 25 0.0200 0.13 Sheet Flow, Grass: Short n= 0.150 P2= 3.10" ' 0.0 10 0.0312 3.59 Shallow Concentrated Flow, Paved Kv= 20.3 fps 1.1 165 0.0160 2.57 Shallow Concentrated Flow, Paved Kv= 20.3 fps ' 4.4 200 Total, Increased to minimum Tc = 5.0 min 1 Proposed Condition Watershed Analysis - Revised 8/31/2015-The Woodlands - Salem MA ' proposed-SUBMITTAL_R Type 111 24-hr 2 yr Rainfall=3.10" Prepared by Microsoft Printed 9/18/2015 HydroCAD® 10.00-15 s/n 06611 ©2015 HydroCAD Software Solutions LLC Page 16 ' Summary for Subcatchment 154S: PR-CB 9+50RT [49] Hint: Tc<2dt may require smaller dt ' Runoff = 0.87 cfs @ 12.07 hrs, Volume= 2,703 cf, Depth= 1.99" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs , Type III 24-hr 2 yr Rainfall=3.10" Area (so CN Description 1,875 98 Unconnected roofs, HSG C 6,425 74 >75% Grass cover, Good, HSG C 7,998 98 Paved parking, HSG C ' 16,298 89 Weighted Average 6,425 39.42% Pervious Area 9,873 60.58% Impervious Area 1,875 18.99% Unconnected Tc Length Slope Velocity Capacity Description ' (min) (feet) (ft/ft) (ft/sec) (cfs) 2.7 40 0.0800 0.24 Sheet Flow, Grass: Short n= 0.150 P2= 3.10" 0.0 10 0.0312 3.59 Shallow Concentrated Flow, Paved Kv= 20.3 fps 1.8 280 0.0160 2.57 Shallow Concentrated Flow, Paved Kv= 20.3 fps 4.5 330 Total, Increased to minimum Tc = 5.0 min Summary for Subcatchment 155S: EX-RES 2R 1 [49] Hint: Tc<2dt may require smaller dt Runoff = 0.49 cfs @ 12.08 hrs, Volume= 1,538 cf, Depth= 1.33" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs ' Type III 24-hr 2 yr Rainfall=3.10" Area (so CN Description 12,285 81 1/3 acre lots, 30% imp, HSG C 1,640 70 Woods, Good, HSG C 13,925 80 Weighted Average 10,240 73.53% Pervious Area , 3,686 26.47% Impervious Area 1 Proposed Condition Watershed Analysis - Revised 8/31/2015- The Woodlands - Salem MA proposed-SUBMITTAL_R Type 11124-hr 2 yr Rainfall=3.10" Prepared by Microsoft Printed 9/18/2015 HydroCAD®10.00-15 s/n 06611 ©2015 HydroCAD Software Solutions LLC Page 17 ' Tc Length Slope Velocity Capacity Description (min) (feet) (f/ft) (f/sec) (cfs) ' 4.3 50 0.0400 0.19 Sheet Flow, Grass: Short n= 0.150 P2= 3.10" 0.4 55 0.0200 2.28 Shallow Concentrated Flow, ' Unpaved Kv= 16.1 fps 4.7 105 Total, Increased to minimum Tc = 5.0 min Summary for Subcatchment 156S: PR-POND 4 [49) Hint: Tc<2dt may require smaller dt ' Runoff = 0.72 cfs @ 12.08 hrs, Volume= 2,275 cf, Depth= 1.26" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs Type III 24-hr 2 yr Rainfall=3.10" Area (sf) CN Description ' 1,500 98 Unconnected roofs, HSG C 15,295 74 >75% Grass cover, Good, HSG C 4,840 91 Rip Rap HSG C ' 21,635 79 Weighted Average. 20,135 93.07% Pervious Area 1,500 6.93%.Impervious Area 1,500 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) ' 2.6 50 0.1500 0.33 Sheet Flow, Grass: Short n= 0.150 P2= 3.10" 0.1 20 0.1200 5.58 Shallow Concentrated Flow, ' Unpaved Kv= 16.1 fps 0.1 30 0.3300 9.25 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 0.0 25 0.3300 9.25 Shallow Concentrated Flow, ' Unpaved Kv= 16.1 fps 2.8 125 Total, Increased to minimum Tc = 5.0 min Summary for Pond 78P: Proposed CULTEC 330XL (Infiltration System #1) Inflow Area = 14,971 sf, 50.97% Impervious, Inflow Depth = 1.76" for 2 yr event ' Inflow 0.69 cfs.@ 12.08 hrs, Volume= 2,196 cf Outflow 0.01 cfs @ 10.75 hrs, Volume= 1,083 cf, Atten= 99%, Lag= 0.0 min Discarded = 0.01 cfs @ 10.75 hrs, Volume= 1,083 cf Secondary = 0.00 cfs @ 0.00 hrs, Volume= 0 cf Routing by Dyn-Stor-Ind method, Time Span 0.00-40.00 hrs, dt= 0.05 hrs/3 Proposed Condition Watershed Analysis - Revised 8/31/2015- The Woodlands - Salem MA proposed-SUBMIITAL_R Type 111 24-hr 2 yr Rainfall=3.10" ! Prepared by Microsoft Printed 9/18/2015 HydroCAD® 10.00-15 s/n 06611 @ 2015 HydroCAD Software Solutions LLC Page 18 Peak Elev= 124.00' @ 22.51 hrs Surf.Area= 1,489 sf Storage= 1,652 cf Plug-Flow detention time= (not calculated: outflow precedes inflow) ! Center-of-Mass det. time= 614.4 min ( 1,428.9 -814.5 ) Volume Invert Avail.Storage Storage Description #1A 122.40' 1,274 cf 25.67'W x 58.001 x 3.54'H Field A 5,272 cf Overall -2,086 cf Embedded = 3,186 cf x 40.0% Voids #2A 122.90' 2,086 cf Cultec R-330XL x 40 Inside#1 Effective Size= 47.8"W x 30.0"H => 7.45 sf x 7.001 = 52.2 cf ! Overall Size= 52.0"W x 30.5"H x 8.501 with 1.50' Overlap 5 Rows of 8 Chambers 3,361 cf Total Available Storage ! Storage Group A created with Chamber Wizard Device Routing Invert Outlet Devices ! #1 Discarded 122.40' 0.270 in/hr Exfiltration over Surface area #2 Secondary 127.75' 4.0' long x 1.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 Coef. (English) 2.69 2.72 2.75 2.85 2.98 3.08 3.20 3.28 3.31 3.30 3.31 3.32 Discarded Outflow Max=0.01 cfs @ 10.75 hrs HW=122.46' (Free Discharge) L1=Exfiltration (Exfiltration Controls 0.01 cfs) Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=122.40' TW=0.00' (Dynamic Tailwater) 2=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) Summary for Pond 142P: Detention Pond 1 Inflow Area = 60,064 sf, 24.18% Impervious, Inflow Depth = 1.29" for 2 yr event ! Inflow = 2.02 cfs @ 12.08 hrs, Volume= 6,445 cf Outflow = 0.50 cfs @ 12.49 hrs, Volume= 6,132 cf, Atten= 75%, Lag= 24.8 min Discarded = 0.01 cfs @ 12.49 hrs, Volume= 688 cf ! Primary = 0.49 cfs @ 12.49 hrs, Volume= 5,444 cf Secondary = 0.00 cfs @ 0.00 hrs, Volume= 0 cf Routing by Dyn-Stor-Ind method, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs/3 , Peak Elev= 134.10' @ 12.49 hrs Surf.Area= 1,653 sf Storage= 2,319 cf Flood Elev= 136.50' Surf.Area= 3,660 sf Storage= 8,258 cf ' Plug-Flow detention time= 136.0 min calculated for 6,132 cf(95% of inflow) Center-of-Mass det. time= 109.6 min ( 949.5- 839.9 ) Volume Invert Avail.Storage Storage Description ' #1 132.00' 8,258 cf Custom Stage Data (Prismatic) Listed below(Recalc) 1 t Proposed Condition Watershed Analysis - Revised 8/31/2015-The Woodlands - Salem MA proposed-SUBMITTAL R Type 11124-hr 2 yr Rainfall=3.10" Prepared by Microsoft Printed 9/18/2015 HydroCAD®10.00-15 s/n 06611 @2015 HvdroCAD Software Solutions LLC Page 19 Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) ' 132.00 600 0 0 133.00 1,060 830 830 134.00 1,590 1,325 2,155 ' 135.00 2,210 1,900 4,055 136.00 2,910 2,560 6,615. 136.50 3,660 1,643 8,258 ' Device Routing Invert Outlet Devices #1 Primary 131.50' 12.0" Round Culvert L= 175.0' CPP, square edge headwall, Ke= 0.500 Inlet/Outlet Invert= 131.50'/ 129.75' S= 0.0100 'P Cc= 0.900 n= 0.010, Flow Area= 0.79 sf #2 Device 1 132.75' 4.0"Vert. Orifice/Grate C= 0.600 #3 Device 1 134.00' 8.0"Vert. Orifice/Grate C= 0.600 #4 Device 1 134.50' 10.0" Vert. Orifice/Grate C= 0.600 #5 Secondary 136.00' 8.0' long x 6.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 ,4.50 5.00 5.50 Coef. (English) 2.37 2.51 2.70 2.68 2.68 2.67 2.65 2.65 2:65 2.65 2.66 2.66 2.67 2.69 2.72 2.76 2.83 1 #6 Discarded 132.00' 0.270 in/hr Exfiltration over Surface area Discarded OutFlow Max=0.01 cfs @ 12.49 hrs HW=134.10' (Free Discharge) t-6=Exfiltration (Exfiltration Controls 0.01 cfs) Primary OutFlow Max=0.49 cfs @ 12.49 hrs HW=134.10' TW=0.00' (Dynamic Tailwater) L =Culvert (Passes 0.49 cfs of 5.29 cfs potential flow) ' 12=Orifice/Grate (Orifice Controls 0.46 cfs @ 5.24 fps) 3=Orifice/Grate (Orifice Controls 0.04 cfs @ 1.08 fps) , -Orifice/Grate ( Controls 0.00 cfs) econdary OutFlow Max=0.00 cfs @ 0.00 hrs HW=132.00' TW=0.00' (Dynamic Tailwater) Broad-Crested Rectangular Weir ( Controls 0.00 cfs) tSummary for Pond 143P: Detention Pond 2 Inflow Area = 44,298 sf, 45.76% Impervious, Inflow Depth = 1.73" for 2 yr event Inflow 2.02 cfs @ 12.08 hrs, Volume= 6,380 cf Outflow - 0.16 cfs @ 13.50 hrs, Volume= 5,934 cf, Atten= 92%, Lag= 85.3 min Discarded = 0.02 cfs @ 13.50 hrs, Volume= 1,852 cf Primary = 0.14 cfs @ 13.50 hrs, Volume= 4,082 cf Secondary= 0.00 cfs @ 0.00 hrs, Volume= 0 cf ' Routing by Dyn-Stor-Ind method, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs/3 Peak Elev= 129.30' @ 13.50 hrs Surf.Area= 3,099 sf Storage= 3,348 cf Flood Elev= 136.50' Surf.Area= 6,340 sf Storage= 17,293 cf Plug-Flow detention time= 355.0 min calculated for 5,927 cf(93% of inflow) Center-of-Mass det. time= 319.4 min ( 1,137.0- 817.7 ) Proposed Condition Watershed Analysis - Revised 8/31/2015-The Woodlands - Salem MA ' proposed-SUBMIITAL_R Type 11124-hr 2 yr Rainfall=3.10" Prepared by Microsoft Printed 9/18/2015 HydroCAD® 10.00-15 s/n 06611 @2015 HydroCAD Software Solutions LLC Page 20 Volume Invert Avail.Storage Storage Description #1 128.00' 17,293 cf Custom Stage Data (Prismatic) Listed below(Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 128.00 1,800 0 0 128.50 2,560 1,090 1,090 129.00 2,890 1,363 2,453 ' 130.00 3,590 3,240 5,693 131.00 4,350 3,970 9,663 132.00 5,160 4,755 14,418 132.50 6,340 2,875 17,293 Device Routing Invert Outlet Devices #1 Primary 127.50' 12.0" Round Culvert L= 16.0' CPP, square edge headwall, Ke= 0.500 Inlet/Outlet Invert= 127.50'1127.00' S= 0.0313? Cc= 0.900 n= 0.010, Flow Area= 0.79 sf ' #2 Secondary 132.00' 8.0' long x 6.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Coef. (English) 2.37 2.51 2.70 2.68 2.68 2.67 2.65 2.65 2.65 2.65 2.66 2.66 2.67 2.69 2.72 2.76 2.83 #3 Discarded 128.00' 0.270 In/hr Exfiltration over Surface area #4 Device 1 128.50' 2.5"Vert. Orifice/Grate C= 0.600 Discarded OutFlow Max=0.02 cfs @ 13.50 hrs HW=129.30' (Free Discharge) t3=Exfiltration (Exfiltration Controls 0.02 cfs) Primary OutFlow Max=0.14 cfs @ 13.50 hrs HW=129.30' TW=0.00' (Dynamic Tailwater) t- =Culvert (Passes 0.14 cfs of 4.31 cfs potential flow) Orifice/Grate (Orifice Controls 0.14 cfs @ 4.01 fps) Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=128.00' TW=0.00' (Dynamic Tailwater) 2=13road-Crested Rectangular Weir ( Controls 0.00 cfs) Summary for Pond 144P: Detention Pond 4 Inflow Area = 67,659 sf, 48.57% Impervious, Inflow Depth = 1.86" for 2 yr event Inflow = 3.32 cfs @ 12.08 hrs, Volume= 10,459 cf Outflow = 1.01 cfs @ 12.41 hrs, Volume= 9,742 cf, Atten= 70%, Lag= 20.1 min , Discarded = 0.02 cfs @ 12.41 hrs, Volume= 1,088 cf Primary = 1.00 cfs @ 12.41 hrs, Volume= 8,654 cf Secondary= 0.00 cfs @ 0.00 hrs, Volume= 0 cf Routing by Dyn-Stor-Ind method, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs/3 , Peak Elev= 119.36' @ 12.41 hrs Surf.Area= 2,611 sf Storage= 3,845 cf Plug-Flow detention time= 145.0 min calculated for 9,742 cf(93%of inflow) Proposed Condition Watershed Analysis - Revised 8/31/2015- The Woodlands - Salem MA ' proposed-SUBMITTAL_R Type ///24-hr 2 yr Rainfall=3.10" Prepared by Microsoft Printed 9/18/2015 HydroCADO 10.00-15 s/n 06611 ©2015 HydroCAD Software Solutions LLC Page 21 Center-of-Mass det. time= 108.8 min ( 922.1 - 813.2 ) ' Volume Invert Avail.Storage Storage Description #1 117.00' 18,006 cf Custom Stage Data (Prismatic) Listed below(Recalc) Elevation Surf.Area Inc.Store Cum.Store ' (feet) (sq-ft) (cubic-feet) (cubic-feet) 117.00 790 0 0 118.00 1,460 1,125 1,125 ' 119.00 2,230 1,845 2,970 120.00 3,285 2,758 5,728 121.00 4,480 3,883 9,610 ' 122.00 5,825 5,153 14,763 122.50 7,150 3,244 18,006 Device Routing Invert Outlet Devices #1 Primary 114.50' 12.0" Round Culvert L= 13.0' CPP, square edge headwall, Ke= 0.500 Inlet/Outlet Invert= 114.50'/ 114.00' S= 0.0385 ? Cc= 0.900 ' n= 0.010, Flow Area= 0.79 sf #2 Discarded 117.00' 0.270 in/hr Exfltration over Surface area #3 Device 1 118.00' 6.0"Vert. Orifice/Grate C= 0.600 #4 Device 1 120.50' 8.0"Vert. Orifice/Grate C= 0.600 #5 Secondary 122.00' 8.0' long x 6.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Coef. (English) 2.37 2.51 2.70 2.68 2.68 2.67 2.65 2.65 2.65 2.65 2.66 2.66 2.67 2.69 2.72.2.76 2.83 ' Discarded OutFlow Max=0.02 cfs @ 12.41 hrs HW=119.36' (Free Discharge) t2=Exfiltration (Exfiltration Controls 0.02 cfs) Primary OutFlow Max=1.00 cfs @ 12.41 hrs HW=1.19.36' TW=0.00' (Dynamic Tailwater) t C Ivert (Passes 1.00 cfs of 7.90 cfs potential flow) 3-Orifice/Grate (Orifice Controls 1.00 cfs @ 5.07 fps) Orifice/Grate ( Controls 0.00 cfs) econdary OutFlow Max=0.00 cfs @ 0.00 hrs HW=117.00' TW=0.00' (Dynamic Tailwater) Broad-Crested Rectangular Weir ( Controls 0.00 cfs) Summary for Pond 152P: Detention Pond 3 ' Inflow Area = 57,305 sf, 37.42% Impervious, Inflow Depth = 1.55" for 2 yr event Inflow 2.28 cfs @ 12.09 hrs, Volume= 7,423 cf Outflow = 0.81 cfs @ 12.40 hrs, Volume= 6,983 cf, Atten= 64%, Lag= 18.3 min Discarded = 0.02 cfs @ 12.40 hrs, Volume= 1,831 cf .' Primary = 0.79 cfs @ 12.40 hrs, Volume= 5,151 cf Secondary = 0.00 cfs @ 0.00 hrs, Volume= 0 cf Routing by Dyn-Stor-Ind method, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs /3 1 Proposed Condition Watershed Analysis - Revised 8/31/2015-The Woodlands ' Salem MA ' proposed-SUBMITTAL_R Type ///24-hr 2 yr Rainfall=3.10" Prepared by Microsoft Printed 9/18/2015 HydroCAD@ 10.00-15 s/n 06611 @2015 HydroCAD Software Solutions LLC Page 22 Peak Elev= 116.06' @ 12.40 hrs Surf.Area= 2,912 sf Storage= 2,701 cf Flood Elev= 136.50' Surf.Area= 5,400 sf Storage= 12,340 cf Plug-Flow detention time= 224.3 min calculated for 6,974 cf(94% of inflow) , Center-of-Mass det. time= 193.6 min ( 1,017.7- 824.1 ) Volume Invert Avail.Storage Storage Description #1 115.00' 12,340 cf Custom Stage Data (Prismatic) Listed below(Recalc) Elevation Surf.Area Inc.Store Cum.Store ' (feet) (sq-ft) (cubic-feet) (cubic-feet) 115.00 2,200 0 0 116.00 2,870 2,535 2,535 117.00 3,600 3,235 5,770 118.00 4,560 4,080 9,850 118.50 5,400 2,490 12,340 Device Routing Invert Outlet Devices #1 Primary 113.50' 12.0" Round Culvert L= 10.0' CPP, square edge headwall, Ke= 0.500 Inlet/Outlet Invert= 113.50'/ 113.00' S= 0.0500 'P Cc= 0.900 n= 0.010, Flow Area= 0.79 sf #2 Device 1 115.50' 8.0"Vert. Orifice/Grate C= 0.600 #3 Secondary 118.00' 8.0' long x 6.0' breadth Broad-Crested RectangularWeir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Coef. (English) 2.37 2.51 2.70 2.68 2.68 2.67 2.65 2.65 2.65 2.65 2.66 2.66 2.67 2.69 2.72 2.76 2.83 #4 Discarded 115.00' 0.270 in/hr Exfiitration over Surface area Discarded OutFlow Max=0.02 cfs @ 12.40 hrs HW=116.06' (Free Discharge) t- 4=Exfiltration (Exfiltration Controls 0.02 cfs) Primary OutFlow Max=0.79 cfs @ 12.40 hrs HW=116.06' TW=0.00' (Dynamic Tailwater) t--1=Culvert (Passes 0.79 cfs of 5.42 cfs potential flow) L2=Orifice/Grate (Orifice Controls 0.79 cfs @ 2.54 fps) Secondary OUtFlow Max=0.00 cfs @ 0.00 hrs HW=115.00' TW=0.00' (Dynamic Tailwater) 3=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) Summary for Link 109L: Total Surface Runoff discharging from project area ' Inflow Area = 751,980 sf, 20.55% Impervious, Inflow Depth = 1.06" for 2 yr event Inflow = 10.88 cfs @ 12.18 hrs, Volume= 66,321 cf Primary = 10.88 cfs @ 12.18 hrs, Volume= 66,321 cf, Atten= 0%, Lag= 0.0 min Primary outflow= Inflow, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs ' Proposed Condition Watershed Analysis - Revised 8/31/2015- The Woodlands - Salem MA ' proposed-SUBMITTAL_R Type ///24-hr 2 yr Rainfall=3.10" Prepared by Microsoft Printed 9/18/2015 HydroCAD®10.00-15 s/n 06611 @2015 HydroCAD Software Solutions LLC Page 23 Summary for Link 128L: Runoff towards existing wetlands to the north ' Inflow Area = 315,936 sf, 19.88% Impervious, Inflow Depth = 1.06" for 2 yr event Inflow 4.48 cfs @ 12.21 hrs, Volume= 28,026 cf Primary = 4.48 cfs @ 12.21 hrs, Volume= 28,026 cf, Atten= 0%, Lag= 0.0 min Primary outflow= Inflow, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs ' Summary for Link 130L: Runoff towards Isolated Wetland "B" series Inflow Area = 70,668 sf, 4.80% Impervious, Inflow Depth = 0.87' for 2 yr event Inflow = 1.15 cfs @ 12.22 hrs, Volume= 5,113 cf ' Primary = 1.15 cfs @ 12.22 hrs, Volume= 5,113 cf, Atten= 0%, Lag= 0.0 min Primary outflow= Inflow, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs ' Summary.for Link 132L: Runoff towards Clark Avenue Drainage System Inflow Area = 123,289 sf, 42.07% Impervious, Inflow Depth = 1.40" for 2 yr event Inflow 4.63 cfs @ 12.08 hrs, Volume= 14,372 cf Primary = 4.63 cfs @ 12.08 hrs, Volume= 14,372 cf, Atten= 0%, Lag= 0.0 min ' Primary outflow= Inflow, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs ' Summary for Link 139L: Runoff towards existing wetlands to the south Inflow Area = 436,044 sf, 21.03% Impervious, Inflow Depth = 1.05" for 2 yr event Inflow = 6.88 cfs @ 12.12 hrs, Volume= 38,296 cf Primary = 6.88 cfs @ 12.12 hrs, Volume= 38,296 cf, Atten= 0%, Lag= 0.0 min Primary outflow= Inflow, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs i Summary for Link 141 L: Runoff towards Isolated Wetland "C" series I ' Inflow Area 49,862 sf, 0.00% Impervious, Inflow Depth = 0.77" for 2 yr event Inflow 0.73 cfs @ 12.20 hrs, Volume= 3,202 cf Primary = 0.73 cfs @ 12.20 hrs, Volume= 3,202 cf, Atten= 0%, Lag= 0.0 min Primary outflow= Inflow, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs 1 1 1 1 ' Proposed Condition Watershed Analysis - Revised 8/31/2015- The Woodlands - Salem MA proposed-SUBMITTAL R Type 11124-hr 10 yr Rainfall=4.50" Prepared by Microsoft Printed 9/18/2015 HydroCAD@ 10.00-15 s/n 06611 @2015 HvdroCAD Software Solutions LLC Page 1 Summary for Subcatchment 80S: PR-CB O+ORT [49] Hint: Tc<2dt may require smaller dt Runoff = 0.46 cfs @ 12.07 hrs, Volume= 1,457 cf, Depth= 3.50" ' Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs Type III 24-hr 10 yr Rainfall=4.50" Area (so CN Description 375 98 Unconnected roofs, HSG C 1,515 74 >75% Grass cover, Good, HSG C ' 3,107 98 Paved parking, HSG C 4,997 91 Weighted Average 1,515 30.32% Pervious Area ' 3,482 69.68% Impervious Area 375 10.77% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 3.3 25 0.0200 0.13 Sheet Flow, Grass: Short n= 0.150 P2= 3.10" ' 0.1 15 0.0312 3.59 Shallow Concentrated Flow, Paved Kv= 20.3 fps 0.6 165 0.0500 4.54 Shallow Concentrated Flow, ' Paved Kv= 20.3 fps 4.0 205 Total, Increased to minimum Tc = 5.0 min Summary for Subcatchment 81 S: PR-CB O+OLT [49] Hint: Tc<2dt may require smaller dt ' Runoff = 0.61 cfs @ 12.08 hrs, Volume= 1,879 cf, Depth= 2.55" ' Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs Type III 24-hr 10 yr Rainfall=4.50" Area (sf) CN Description 1 375 70 . Woods, Good, HSG.0 3,751 74 >75% Grass cover, Good, HSG C 3,023 98 Paved parking, HSG C ' 1,700 70 Woods, Good, HSG C 8,849 81 Weighted Average 5,826 65.84% Pervious Area 3,023 34.16% Impervious Area Proposed Condition Watershed Analysis - Revised 8/31/2015- The Woodlands - Salem MA proposed-SUBMITTAL_R Type ll/24-hr 10 yr Rainfall=4.50" Prepared by Microsoft Printed 9/18/2015 HydroCAD® 10.00-15 s/n 06611 @ 2015 HydroCAD Software Solutions LLC Page 2 ' Tc . Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 3.3 25 0.0200 0.13 Sheet Flow, Grass: Short n= 0.150 P2= 3.10" 0.1 15 0.0312 3.59 Shallow Concentrated Flow, Paved Kv= 20.3 fps 0.6 160 0.0500 4.54 Shallow Concentrated Flow, Paved Kv= 20.3 fps 4.0 200 Total, Increased to minimum Tc = 5.0 min Summary for Subcatchment 111 S: EX-1 R Runoff = 7.10 cfs @ 12.20 hrs, Volume= 28,831 cf, Depth= 1.82" ' Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs Type III 24-hr 10 yr Rainfall=4.50" ' Area (sf) CN Description 141,864 70 Woods, Good, HSG C 37,700 74 >75% Grass cover, Good, HSG C 6,000 98 Unconnected roofs, HSG C 4,490 91 Rip rap slope, HSG C t 190,054 72 Weighted Average 184,054 96.84% Pervious Area 6,000 3.16% Impervious Area 6,000 100:00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 12.5 .100 0.0800 0.13 Sheet Flow, Woods: Light underbrush n= 0.400 P2= 3.10" 0.4 100 0.0800 4.55 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 0.7 275 0.1500 6.24 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps ' 13.6 475 Total Summary for Subcatchment 136S: EX-4R ' Runoff = 2.60 cfs @ 12.21 hrs, Volume= 10;720 cf, Depth= 1.82" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs ' Type III 24-hr 10 yr Rainfall=4.50" Proposed Condition Watershed Analysis - Revised 8/31/2015- The Woodlands - Salem MA ' proposed-SUBMITTAL_R Type 111 24-hr 10 yr Rainfall=4.50" Prepared by Microsoft Printed 9/18/2015 HydroCAD® 10.00-15 s/n 06611 @ 2015 HydroCAD Software Solutions LLC Pa-ge 3 Area (so CN Description 51,513 70 Woods, Good, HSG C 2,250 98 Unconnected roofs, HSG C 1,142 98 Unconnected pavement, HSG C 15,763 74 >75% Grass cover, Good, HSG C 70,668 72 Weighted Average 67,276 95.20% Pervious Area 3,392 4.80% Impervious Area 3,392 100.00% Unconnected ' Tc Length Slope Velocity Capacity Description (min) (feet) (f/ft) (ft/sec) (cfs) ' 12.5 100 0.0800 0.13 Sheet Flow, Woods: Light underbrush n= 0.400 P2= 3.10" 0.4 100 0.0800 4.55 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 1.3 220 0.0300 2.79 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 14.2 420 Total Summary for Subcatchment 137S: EX-2r ' [49] Hint: Tc<2dt may require smaller dt Runoff = 0.74 cfs @ 12.08 hrs, Volume= 2,303 cf, Depth= 2.05" ' Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs Type III 24-hr 10 yr Rainfall=4.50" ' Area (so CN Adi Description 500 70 Woods, Good, HSG C ' 375 98 Unconnected roofs, HSG C 1,240 98 Unconnected pavement, HSG C 11,363 74 , >75% Grass cover, Good, HSG C 13,478 77 75 Weighted Average, UI Adjusted ' 11,863 88.02% Pervious Area 1,615 11.98% Impervious Area 1,615 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) ' 3.3 50 0.0800 0.25 Sheet Flow, Grass: Short n= 0.150 P2= 3.10" 0.5 100 0.0400 3.22 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 0.6 95 0.0260 2.60 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 0.1 35 0.1100 5.34 Shallow Concentrated Flow, ' Unpaved Kv= 16.1 fps 4.5 280 Total, Increased to minimum Tc = 5.0 min Proposed Condition Watershed Analysis - Revised 8/31/2015-The Woodlands - Salem MA ' proposed-SUBMITTAL_R Type 111 24-hr 10 yr Rainfall=4.50" Prepared by Microsoft Printed 9/18/2015 HydroCAD®10.00-15 s/n 06611 @2015 HydroCAD Software Solutions LLC Paae 4 ' Summary for Subcatchment 138S: EX-3R Runoff = 6.59 cfs @ 12.23 hrs, Volume= 28,435 cf, Depth= 1.75" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs Type III 24-hr 10 yr Rainfall=4.50" Area (sf) CN Description 400 81 1/3 acre lots, 30% imp, HSG C ' 159,236 70 Woods, Good, HSG C 3,750 98 Unconnected roofs, HSG C 32,000 74 >75% Grass cover, Good, HSG C ' 195,386 71 Weighted Average 191,516 98.02% Pervious Area 3,870 1.98% Impervious Area 3,750 96.90% Unconnected ' Tc Length Slope Velocity Capacity Description (min) (feet) (f/ft) (ft/sec) (cfs) 14.8 100 0.0530 0.11 Sheet Flow, Woods: Light underbrush n= 0.400 P2= 3.10" 0.5 180 0.1700 6.64 Shallow Concentrated Flow, ' Unpaved Kv= 16.1 fps 0.3 45 0.0200 2.28 Shallow Concentrated Flow, 15.6 325 Total Unpaved Kv= 16.1 fps ' Summary for Subcatchment 14OS: EX-5 (No Change) Runoff = 1.74 cfs @ 12.18 hrs, Volume= 6,955 cf, Depth= 1.67" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs ' Type III 24-hr 10 yr Rainfall=4.50" I Area (so CN Description ' 49,862 70 Woods, Good, HSG C 49,862 100.00% Pervious Area Tc- Length Slope Velocity Capacity Description ' (min) (feet) (ft/ft) (f/sec) (cfs) 10.0 100 0.1400 0.17 Sheet Flow, ' Woods: Light underbrush n= 0.400 P2= 3.10" 0.3 100 0.1400 6.02 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 2.0 360 0.0360 3.05 Shallow Concentrated Flow, ' Unpaved Kv= 16.1 fps 12.3 560 Total Proposed Condition Watershed Analysis - Revised 8/31/2015- The Woodlands - Salem MA proposed-SUBMITTAL_R Type ///24-hr 10 yr Rainfall=4.50" Prepared by Microsoft Printed 9/18/2015 HydroCAD®10.00-15 s/n 06611 ©2015 HydroCAD Software Solutions LLC Page 5 Summary for Subcatchment 142S: PR- POND 2 ' [49] Hint: Tc<2dt may require smaller dt Runoff = 0.79 cfs @ 12.08 hrs, Volume= 2,471 cf, Depth= 2.05' Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs Type III 24-hr 10 yr Rainfall=4.50" ' Area (sf) CN Description 13,712 74 >75% Grass cover, Good, HSG C 750 98 Unconnected roofs, HSG C ' 14,462 75 Weighted Average 13,712 94.81% Pervious Area 750 5.19% Impervious Area ' 750 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 3.5 50 0.0700 0.24 Sheet Flow, Grass: Short n= 0.150 P2= 3.10" 0.1 20 0.0700 4.26 Shallow Concentrated Flow, ' Unpaved Kv= 16.1 fps. 0.0 15 0.3300 9.25 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps ' 3.6 85 Total, Increased to minimum Tc = 5.0 min Summary for Subcatchment 143S: PR-POND 1 ' [49].Hint: Tc<2dt may require smaller dt Runoff = 2.37 cfs @ 12.08 hrs, Volume= 7,368 cf, Depth= 2.05' Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs ' Type III 24-hr 10 yr Rainfall=4.50" Area (so CN Adj Description 4,125 98 Unconnected roofs, HSG C 33,998 74 >75% Grass cover, Good, HSG C 5,000 70 Woods, Good, HSG C 43,123 76 75 Weighted Average, UI Adjusted ' 38,998 90.43% Pervious Area 4,125 9.57% Impervious Area 4,125 100.00% Unconnected 1 Proposed Condition Watershed Analysis - Revised 8/31/2015--The Woodlands -Salem MA ' proposed-SUBMITTAL_R Type ll/24-hr 10 yr Rainfall=4.50" Prepared by Microsoft Printed 9/18/2015 HydroCAD@ 10.00-15 s/n 06611 @ 2015 HydroCAD Software Solutions LLC Page 6 ' Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 3.8 50 0.0550 0.22 Sheet Flow, Grass: Short n= 0.150 P2= 3.10" 1.1 170 0.0250 2.55 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 0.1 65 0.3300 9.25 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 5.0 285 Total ' Summary for Subcatchment 144S: PR-CB 1+65 RT [49] Hint: Tc<2dt may require smaller dt Runoff = 0.67 cfs @ 12.07 hrs, Volume= 2,105 cf, Depth= 3.20" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs Type III 24-hr 10 yr Rainfall=4.50" Area (sf) CN Description ' 1,125 98 Unconnected roofs, HSG C 3,458 98 Paved parking, HSG C 3,319 74 >75% Grass cover, Good, HSG C 7,902 88 Weighted Average 3,319 42.00% Pervious Area ' 4,583 58.00% Impervious Area 1,125 24.55% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (f/sec) (cfs) 3.3 25 0.0200 0.13 Sheet Flow, Grass: Short n= 0.150 P2= 3.10" ' 0.0 10 0.0312 3.59 Shallow,Concentrated Flow, .Paved Kv= 20.3 fps 0.6 165 0.0500 4.54 Shallow Concentrated Flow, Paved Kv= 20.3 fps 3.9 200 Total, Increased to minimum Tc = 5.0 min j Summary for Subcatchment 145S: PR-CB 3+50LT ' [49] Hint: Tc<2dt may require smaller dt ' Runoff = 1.42 cfs @ 12.08 hrs, Volume= 4,537 cf, Depth= 3.30" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs , Type III 24-hr 10 yr Rainfall=4.50" ' Proposed Condition Watershed Analysis - Revised 8/31/2015-The Woodlands - Salem MA proposed-SUBMITTAL R Type 11124-hr 10 yr Rainfall=4.50" Prepared by Microsoft Printed 9/18/2015 HydroCAD@ 10.00-15 s/n 06611 @2015 HydroCAD Software Solutions LLC Page 7 1 Area (so CN Description 2,625 98 Unconnected roofs, HSG C ' 7,358 98 Paved parking, HSG C 6,539 74 >75% Grass cover, Good, HSG C 16,522 89 Weighted Average ' 6,539 39.58% Pervious Area 9,983 60.42% Impervious Area 2,625 26.29% Unconnected ' Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 3.6 20 0.0100 0.09 Sheet Flow, ' Grass: Short n= 0.150 P2= 3.10" 0.0. 10 0.0312 3.59 Shallow Concentrated Flow, Paved Kv= 20.3 fps ' 1.7 285 0.0200 2.87 Shallow Concentrated Flow, Paved Kv= 20.3 fps 5.3 315 Total Summary for Subcatchment 146S: PR-CB 3+50RT ' [49] Hint: Tc<2dt may require smaller dt Runoff - 1.22 cfs @ 12.07 hrs, Volume= 3,881 cf, Depth= 3.50" ' Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs Type III 24-hr 10 yr Rainfall=4.50" ' Area (sf) CN Description 2,625 98 Unconnected roofs, HSG C 6,914 98 Paved parking, HSG C ' 3,775 74 >75% Grass cover, Good, HSG C 13,314 91 Weighted Average 3,775 28.35% Pervious Area ' 9,539 71.65% Impervious Area 2,625 27.52% Unconnected Tc Length Slope Velocity Capacity Description ' (min) (feet) (ft/ft) (f/sec) (cfs) 2.9 15 0.0100 0.09 Sheet Flow, Grass: Short n= 0.150 P2= 3.10" 0.0 10 0.0312 3.59 Shallow Concentrated Flow, Paved Kv= 20.3 fps 1.7 285 0.0200 2.87 Shallow Concentrated Flow, Paved Kv= 20.3 fps 4.6 310 Total, Increased to minimum Tc = 5.0 min Proposed Condition Watershed Analysis - Revised 8/31/2015-The Woodlands - Salem MA proposed-SUBMITTAL_R Type ///24-hr 10 yr Rainfall=4.50" Prepared by Microsoft Printed 9/18/2015 HydroCAD®10.00-15 s/n 06611 @ 2015 HydroCAD Software Solutions LLC Page 8 ' Summary for Subcatchment 147S: PR-CB 1+65 LT [49] Hint: Tc<2dt may require smaller dt ' Runoff = 0.79 cfs @ 12.07 hrs, Volume= 2,482 cf, Depth= 3.30" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.0040.00 hrs, dt= 0.05 hrs , Type III 24-hr 10 yr Rainfall=4.50" Area (so CN Description ' 1,500 98 Unconnected roofs, HSG C 4,314 98 Paved parking, HSG C ' 3,225 74 >75% Grass cover, Good, HSG C 9,039 89 Weighted Average 3,225 35.68% Pervious Area 5,814 64.32% Impervious Area ' 1,500 25.80% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 3.3 25 0.0200 0.13 Sheet Flow, Grass: Short n= 0.150 P2= 3.10" ' 0.0 10 0.0312 3.59 Shallow Concentrated Flow, Paved Kv= 20.3 fps 0.6 165 0.0500 4.54 Shallow Concentrated Flow, Paved Kv= 20.3 fps ' 3.9 200 Total, Increased to minimum Tc = 5.0 min Summary for Subcatchment 148S: 3/4 roof area Lot 12 ' [49] Hint: Tc<2dt may require smaller dt Runoff = 0.11 cfs @ 12.07 hrs, Volume= 400 cf, Depth= 4.26" ' Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs ' Type III 24-hr 10 yr Rainfall=4.50" Area (so CN Description ' 1,125 98 Roofs, HSG C 1,125 100.00% Impervious Area Tc Length Slope Velocity Capacity Description ' (min) (feet) (ft/ft) (f/sec) (cfs) 1.0 Direct Entry, 1.0 0 Total, Increased to minimum Tc= 5.0 min Proposed Condition Watershed Analysis - Revised 8/31/2015- The Woodlands - Salem MA proposed-SUBMITTAL_R Type 11124-hr 10 yr Rainfall=4.50" Prepared by Microsoft Printed 9/18/2015 HydroCAD@ 10.00-15 s/n 06611 @ 2015 HydroCAD Software Solutions LLC Page 9 Summary for Subcatchment 149S: EX-RES 1 r ' [49] Hint: Tc<2dt may require smaller dt Runoff = 7.42 cfs @ 12.07 hrs, Volume= 22,992 cf, Depth= 2.91" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs Type III 24-hr 10 yr Rainfall=4.50" ' Area (so CN Description 61,852 81 1/3 acre lots, 30% imp, HSG C 24,065 98 Paved parking, HSG C ' 7,317 74 >75% Grass cover, Good, HSG C 1,606 70 Woods, Good, HSG C 94,840 85 Weighted Average ' 52,219 55.06% Pervious Area 42,621 44.94% Impervious Area ' Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 3.5 . 50 0.0700 0.24 Sheet Flow, Grass: Short n= 0.150 P2= 3.10" 0.3 100 0.1000 5.09 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps -1.2 150 0.0100 2.03 `Shallow Concentrated Flow, ' Paved Kv= 20.3 fps 5.0 300 Total Summary for Subcatchment 150S: PR-CB Road B Runoff = 2.70 cfs @ 12.09 hrs, Volume= 8,901 cf, Depth= 3.40" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs Type Ill.24-hr 10 yr Rainfall=4.50" . Area (so CN Description. 3,750 98 Unconnected roofs, HSG C 10,385 74 >75% Grass cover, Good, HSG C t 17,318 98 Paved parking, HSG C 31,453 90 Weighted Average 10,385 33.02% Pervious Area ' 21,068 66.98% Impervious Area 3,750 17.80% Unconnected F Proposed Condition Watershed Analysis - Revised 8/31/2015-The Woodlands - Salem MA proposed-SUBMITTAL-111 Type ll/24-hr 10 yr Rainfall=4.50" Prepared by Microsoft Printed 9/18/2015 HydroCAD®10.00-15 s/n 06611 @2015 HydroCAD Software Solutions LLC Page 10 Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) {cfs) 4.3 35 0.0200 0.14 Sheet Flow, ' Grass: Short n= 0.150 P2= 3.10" 0.0 10 0.0312 3.59 Shallow Concentrated Flow, Paved Kv= 20.3 fps ' 2.2 270 0.0100 2.03 Shallow.Concentrated Flow, Paved Kv= 20.3 fps 6.5 315 Total ' Summary for Subcatchment 151 S: PR-POND 3 [49] Hint: Tc<2dt may require smaller dt , Runoff = 1.30 cfs @ 12.08 hrs, Volume= 4,084 cf, Depth= 1.90" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs Type III 24-hr 10 yr Rainfall=4.50" Area (sf) CN Ad) Description 375 .98 Unconnected roofs, HSG C 20,077 74 >75% Grass cover, Good, HSG C 5,400 70 Woods, Good, HSG C 25,852 74 73 Weighted Average, UI Adjusted 25,477 98.55% Pervious Area 375 1.45% Impervious Area 375 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (f/sec) (cfs) 2.4 50 0.1700 0.34 Sheet Flow, Grass: Short n= 0.150 P2= 3.10" 0.3 115 0.1700 6.64 Shallow Concentrated Flow, , Unpaved Kv= 16.1 fps 0.0 10 0.3300 9.25 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 2.7 175 Total, Increased to minimum Tc = 5.0 min Summary for Subcatchment 152S: PR-CB 9+50LT ' [49] Hint: Tc<2dt may require smaller dt ' Runoff = 1.29 cfs @ 12.07 hrs, Volume= 4,120 cf, Depth= 3.50" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs Type III 24-hr 10 yr Rainfall=4.50" 1 ' Proposed Condition Watershed Analysis - Revised 8/31/2015- The Woodlands - Salem MA proposed-SUBMITTAL R Type l/l 24-hr 10 yr Rainfall=4.50" Prepared by Microsoft Printed 9/18/2015 HydroCAD@ 10.00-15 s/n 06611 @2015 HydroCAD Software Solutions LLC Page 11 ' Area (sf) CN Description 2,625 98 Unconnected roofs, HSG C 4,401 74 >75% Grass cover, Good, HSG C 7,107 98 Paved parking, HSG C 14,133 91 Weighted Average ' 4,401 31.14% Pervious Area 9,732 68.86% Impervious Area 2,625 26.97% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (f/sec) (cfs) 3.3 25 0.0200 0.13 Sheet Flow, ' Grass: Short n= 0.150 P2= 3.10" 0.0 10 0.0312 3.59 Shallow Concentrated.Flow, Paved Kv= 20.3 fps ' 1.7 260 0.0160 2.57 Shallow Concentrated Flow, Paved Kv=20.3 fps 5.0 295 Total Summary for Subcatchment 153S: PR-CB 10+84 ' [49] Hint: Tc<2dt may require smaller dt Runoff - 1.45 cfs @ 12.07 hrs, Volume= 4,681 cf, Depth= 3.60" ' Runoff by SCS TR-20 method, UH=SCS, Weighted-CN,Time Span= 0.00-40.00 hrs, dt= 0.05 hrs Type III 24-hr 10 yr Rainfall=4.50" ' Area (so CN Description 1,875 98 Unconnected roofs, HSG C 3,834 74 >75% Grass cover, Good, HSG C ' 9,884 98 Paved parking, HSG C 15,593 92 Weighted Average 3,834 24.59% Pervious Area 11,759 75.41% Impervious Area 1,875 15.95% Unconnected Tc Length Slope Velocity Capacity Description ' (min) (feet) (f/ft) (f/sec) (cfs) 3.3 25 0.0200 0.13 Sheet Flow, Grass: Short n= 0.150 P2= 3.10" ' 0.0 10 0.0312 3.59 Shallow Concentrated Flow, Paved Kv= 20.3 fps ! 1.1 165 0.0160 2.57 Shallow Concentrated Flow, Paved Kv= 20.3 fps 4.4 200 Total, Increased to minimum Tc = 5.O min 1 Proposed Condition Watershed Analysis - Revised 8/31/2015-The Woodlands -Salem MA proposed-SUBMITTAL_R Type 111 24-hr 10 yr Rainfall=4.50" Prepared by Microsoft Printed 9/18/2015 HydroCAD@ 10.00-15 s/n 06611 @ 2015 HydroCAD Software Solutions LLC Paae 12 ' Summary for Subcatchment 154S: PR-CB 9+50RT [49] Hint: Tc<2dt may require smaller dt Runoff = 1.42 cfs @ 12.07 hrs, Volume= 4,475 cf, Depth= 3.30" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs ' Type III 24-hr 10 yr Rainfall=4.50" Area (so CN Description ' 1,875 98 Unconnected roofs, HSG C 6,425 74 >75% Grass cover, Good, HSG C ' 7,998 98 Paved parking, HSG C 16,298 89 Weighted Average 6,425 39.42% Pervious Area 9,873 60.58% Impervious Area ' 1,875 18.99% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet] (ft/ft] (ft/sec) (cfs] ' 2.7 40 0.0800 0.24 Sheet Flow, Grass: Short n= 0.150 P2= 3.10" ' 0.0 10 0.0312 3.59 Shallow Concentrated Flow, Paved Kv= 20.3 fps 1.8 280 0.0160 2.57 Shallow Concentrated Flow, ' Paved Kv= 20.3 fps 4.5 330 Total, Increased to minimum Tc = 5.0 min Summary for Subcatchment 155S: EX-RES 2R [49] Hint: Tc<2dt may require smaller dt Runoff = 0.92 cfs @ 12.08 hrs, Volume= 2,856 cf, Depth= 2.46" ' Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs ' Type III 24-hr 10 yr Rainfall=4.50" Area (so CN Description 12,285 81 1/3 acre lots, 30% imp, HSG C ' 1,640 70 Woods, Good, HSG C 13,925 80 Weighted Average 10,240 73.53% Pervious Area ' 3,686 26.47% Impervious Area 1 1 Proposed Condition Watershed Analysis - Revised 8/31/2015- The Woodlands , Salem MA proposed-SUBMITTAL R Type 111 24-hr 10 yr Rainfall=4.50" Prepared by Microsoft Printed 9/18/2015 HydroCAD@ 10.00-15 s/n 06611 @2015 HydroCAD Software Solutions.LLC Page 13 Tc Length Slope Velocity Capacity Description (min) (feet) (f/ft) (f/sec) (cfs) 4.3 50 0.0400 0.19 Sheet Flow, Grass: Short n= 0.150 P2= 3.10" 0.4 55 0.0200 2.28 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 4.7 -105 Total, Increased to minimum Tc = 5.0 min ' Summary for Subcatchment 156S: PR-POND 4 [49] Hint: Tc<2dt may require smaller dt Runoff = 1.38 cfs @ 12.08 hrs, Volume= 4,285 cf, Depth= 2.38" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs ' Type III 24-hr 10 yr Rainfall=4.50" Area (so CN Description 1,500 98 Unconnected roofs, HSG C 15,295 74 >75% Grass cover, Good, HSG C 4,840 91 Rip Rap, HSG C 21,635 79 Weighted Average ' 20,135 93.07% Pervious Area 1,500 6.93% Impervious Area 1,500 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) ' 2.6 50 0.1500 0.33 Sheet Flow, Grass: Short n= 0.150 P2= 3.10" 0.1 20 0.1200 5.58 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 0.1 30 0.3300 9.25 Shallow Concentrated Flow, Unpaved. Kv= 16.1 fps ' 0.0 25 . 0.3300 9.25 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 2.8 125 Total, Increased to minimum Tc = 5.0 min Summary for Pond 7813: Proposed CULTEC 330XL (Infiltration System #1) Inflow Area = 14,971 sf, 50.97% Impervious, Inflow Depth = 2.99" for .10 yr event ' Inflow 1.18 cfs @ 12.07 hrs, Volume= 3,735 cf Outflow 0.01 cfs @ 9.45 hrs, Volume= 1,133 cf, Atten= 99%, Lag= 0.0 min Discarded = 0.01 cfs @ 9.45 hrs, Volume= 1,133 cf ' Secondary = 0.00 cfs @ 0.00 hrs, Volume= 0 cf Routing by DynStor-Ind method, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs/3 Proposed Condition Watershed Analysis - Revised 8/31/2015- The Woodlands - Salem MA proposed-SUBMITTAL_R Type 111 24-hr 10 yr Rainfall=4.50" Prepared by Microsoft Printed 9/18/2015 HydroCAD®10.00-15 s/n 06611 @ 2015 HydroCAD Software Solutions LLC Page 14 , ' Peak Elev= 125.56' @ 24.04 hrs Surf.Area= 1,489 sf Storage= 3,136 cf Plug-Flow detention time= (not calculated: outflow precedes inflow) Center-of-Mass det. time= 582.1 min ( 1,383.9- 801.8 ) Volume Invert Avail.Storage Storage Description #1A 122.40' 1,274 cf 25.67'W x 58.001 x 3.54'H Field A 5,272 cf Overall -2,086 cf Embedded = 3,186 cf x 40.0% Voids #2A 122.90' 2,086 cf Cultec R-330XL x 40 Inside#1 ' Effective Size= 47.8"W x 30.0"H => 7.45 sf x 7.001 = 52.2 cf Overall Size= 52.0"W x 30.5"H x 8.50'L with 1.50' Overlap 5 Rows of 8 Chambers 3,361 cf Total Available Storage Storage Group A created with Chamber Wizard Device Routing Invert Outlet Devices #1 Discarded 122.40' 0.270 in/hr Exfiltration over Surface area #2 Secondary 127.75' 4.0' long x 1.0' breadth Broad-Crested Rectangular Weir 1 Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 Coef. (English) 2.69 2.72 2.75 2.85 2.98 3.08 3.20 3.28 3.31 3.30 3.31 3.32 Discarded OutFlow Max=0.01 cfs @ 9.45 hrs HW=122.46' (Free Discharge) 1=Exfiltration (Exfiltration Controls 0.01 cfs) Secondary OutFlow, Max=0.00 cfs @ 0.00 hrs HW=122.40' TW=0.00' (Dynamic Tailwater) 2=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) ' Summary for Pond 142P: Detention Pond 1 Inflow Area = 60,064 sf, 24.18% Impervious, Inflow Depth = 2.39" for 10 yr event Inflow = 3.81 cfs @ 12.08 hrs, Volume= 11,955 cf Outflow = 1.83 cfs @ 12.25 hrs, Volume= 11,637 cf, Atten= 52%, Lag= 10.6 min Discarded = 0.01 cfs @ 12.25 hrs, Volume= 748 cf Primary = 1.82 cfs @ 12.25 hrs, Volume= 10,889 cf Secondary= 0.00 cfs @ 0.00 hrs, Volume= 0 cf Routing by.Dyn-Stor-Ind method, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs/3 i Peak Elev= 134.73' @ 12.25 hrs Surf.Area= 2,042 sf Storage= 3,479 cf Flood Elev= 136.50' Surf.Area= 3,660 sf Storage= 8,258 cf ' Plug-Flow detention time= 90.7 min calculated for 11,623 cf(97% of inflow) Center-of-Mass det. time= 76.4 min ( 900.1 -823.7 ) Volume. Invert Avail.Storage Storage Description ' #1 132.00' 8,258 cf Custom Stage Data (Prismatic) Listed below(Recalc) Proposed Condition Watershed Analysis - Revised 8/31/2015- The Woodlands -Salem MA ' proposed-SUBMITTAL_R Type 111 24-hr 10 yr Rainfall=4.50" Prepared by Microsoft Printed 9/18/2015 HydroCAD® 10.00-15 s/n 06611 ©2015 HydroCAD Software Solutions LLC Paae 15 Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) ' 132.00 600 0 0 133.00 1,060 830 830 134.00 1,590 1,325 2,155 ' 135.00 2,210 1,900 4,055 136.00 2,910 2,560 6,615 136.50 3,660 1,643 8,258 ' Device Routing Invert Outlet Devices #1 Primary 131.50' 12.0" Round Culvert L= 175.0' CPP, square edge headwall, Ke= 0.500 ' Inlet/Outlet Invert= 131.50'/ 129.75' S= 0.0100 ? Cc= 0.900 n= 0.010, Flow Area= 0.79 sf #2 Device 1 132.75' 4.0"Vert. Orifice/Grate C= 0.600 #3 Device 1 134.00' 8.0"Vert. Orifice/Grate C= 0.600 94 Device 1 134.50' 10.0"Vert. Orifice/Grate C= 0.600 #5 Secondary 136.00' 8.0' long x 6.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 ' 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Coef. (English) 2.37 2.51 2.70 2.68 2.68 2.67 2.65 2.65 2.65 2.65 2.66 2.66 2.67 2.69 2.72 2.76 2.83 ' #6 Discarded 132.00' 0.270 in/hr Exfiltration over Surface area Discarded OutFlow Max=0.01 cfs @ 12.25 hrs HW=134.73' (Free Discharge) t-6--Exfiltration (Exfiltration Controls 0.01 cfs) Primary OutFlow Max=1.82 cfs @ 12.25 hrs HW=134.73' TW=0.00' (Dynamic Tailwater) L =Culvert (Passes 1.82 cfs of 5.77 cfs potential flow) 2=Oriice/Grate (Orifice Controls 0.57 cfs @ 6.48 fps) 3=Orifice/Grate (Orifice Controls 1.06 cfs @ 3.02 fps) -Orifice/Grate (Orifice Controls 0.20 cfs @ 1.63 fps) econdary OutFlow Max=0.00 cfs @ 0.00 hrs HW=132.00' TW=0.00' (Dynamic Tailwater) =Broad-Crested Rectangular Weir ( Controls 0.00 cfs) Summary for Pond 143P: Detention Pond 2 1 Inflow Area = 44,298 sf, 45.76% Impervious, Inflow Depth = 2.95" for 10 yr event Inflow 3.42 cfs @ 12.08 hrs, Volume= 10,889 cf Outflow 0.23 cfs @ 13.77 hrs, Volume= 10,272 cf, Atten= 93%, Lag= 101.4 min Discarded = 0.02 cfs @ 13.77 hrs, Volume= 2,110 cf ' Primary = 0.20 cfs @ 13.77 hrs, Volume= 8,163 cf Secondary = 0.00 cfs @ 0.00 hrs, Volume= 0 cf ' Routing by Dyn-Stor-Intl method;Time Span= 0.00-40.00 hrs, dt= 0.05 hrs/3 Peak Elev= 180.12' @ 13.77 hrs Surf.Area= 3,683 sf Storage= 6,135 cf Flood Elev= 136.50' Surf.Area= 6,340 sf Storage= 17,293 cf Plug-Flow detention time= 375.1 min calculated for 10,259 cf(94% of inflow) Center-of-Mass det. time= 345.1 min ( 1,149.1 - 804.1 ) Proposed Condition Watershed Analysis - Revised 8/31/2015-The Woodlands - Salem MA proposed-SUBMITTAL_R Type 111 24-hr 10 yr Rainfall=4.50" Prepared by Microsoft Printed 9/18/2015 HydroCAD®10.00-15 s/n 06611 ©2015 HydroCAD Software Solutions LLC Page 16 ' Volume Invert Avail.Storage Storage Description #1 128.00' 17,293 cf Custom Stage Data (Prismatic) Listed below(Recalc) ' Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 128.00 1,800 0 0 128.50 2,560 1,090 1,090 129.00 2,890 1,363 2,453 ' 130.00 3,590 3,240 5,693 131.00 4,350 3,970 9,663 132.00 5,160 4,755 14,418 132.50 6,340 2,875 17,293 , Device Routing Invert Outlet Devices #1 Primary 127.50' 12.0" Round Culvert ' L= 16.0' CPP, square edge headwall, Ke= 0.500 Inlet/Outlet Invert= 127.50'/ 127.00' S= 0.0313 'P Cc= 0.900 n=0.010, Flow Area= 0.79 sf #2 Secondary 132.00' 8.0' long x 6.0' breadth Broad-Crested Rectangular Weir 1 Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Coef. (English) 2.37 2.51 2.70 2.68 2.68 2.67 2.65 2.65 2.65 ' 2.65 2.66 2.66 2.67 2.69 2.72 2.76 2.83 #3 Discarded 128.00' 0.270 in/hr Exfltration over Surface area #4 Device 1 128.50' 2.5"Vert. Orifice/Grate C= 0.600 ' Discarded OutFlow Max=0.02 cfs @ 13.77 hrs HW=130.12' (Free Discharge) t3=Exfiltration (Exfiltration Controls 0.02 cfs) ' Primary OutFlow Max=0.20 cfs @ 13.77 hrs HW=130.12' TW=0.00' (Dynamic Tailwater) t4=Culvert (Passes 0.20 cfs of 5.51 cfs potential flow) Orifice/Grate (Orifice Controls 0.20 cfs @ 5.93 fps) Mndary OutFlow Max=0.00 cfs @ 0.00 hrs HW=128.00' TW=0.00' (Dynamic Tailwater) =Broad-Crested Rectangular Weir ( Controls 0.00 cfs) Summary for Pond 144P: Detention Pond 4 Inflow Area = 67,659 sf, 48.57% Impervious, Inflow Depth = 3.11" . for 10 yr event Inflow = 5.55 cfs @• 12.07 hrs, Volume= 17,560 cf Outflow = 1.35 cfs @ 12.46 hrs, Volume= 16,836 cf, Atten=76%, Lag= 23.3 min ' Discarded = 0.02 cfs @ 12.46 hrs, Volume= 1,197 cf Primary = 1.32 cfs @ 12.46 hrs, Volume= 15,638 cf Secondary = 0.00 cfs @ 0.00 hrs, Volume= 0 cf Routing by Dyn-Stor-Ind method, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs/3 ' Peak Elev= 120.21' @ 12.46 hrs Surf.Area= 3,541 sf Storage= 6,457 cf Plug-Flow detention time= 112.8 min calculated for 16,815 cf(96% of inflow) t ' Proposed Condition Watershed Analysis - Revised 8/31/2015-The Woodlands - Salem MA proposed-SUBMITTAL_R Type l/l 24-hr 10 yr Rainfall=4.50" Prepared by Microsoft Printed 9/18/2015 HydroCAD® 10.00-15 s/n 06611 @2015 HydroCAD Software Solutions LLC Page 17 Center-of-Mass det. time= 90.5 min ( 890.2 - 799.7 ) Volum_ a Invert Avail.Storage Storage Description #1 117.00' 18,006 cf Custom Stage Data (Prismatic) Listed below(Recalc) ' Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 117.00 790 0 0 118.00 1,460 1,125 1,125 119.00 2,230 1,845 2,970 120.00 3,285 2,758 5,728 121.00 4,480 3,883 9,610 122.00 5,825 5,153 14,763 122.50 7,150 3,244 18,006 Device Routing Invert Outlet Devices #1 Primary 114.50' 12.0" Round Culvert L= 13.0' CPP, square edge headwall, Ke= 0.500 ' Inlet/Outlet Invert= 114.50'/ 114.00' S= 0.0385 'P Cc= 0.900 n= 0.010, Flow Area= 0.79 sf #2 Discarded 117.00' 0.270 in/hr Exfiltration over Surface area #3 Device 1 118.00' 6.0"Vert. Orifice/Grate C= 0.600 ' #4 Device 1 120.50' 8.0"Vert. Orifice/Grate C= 0.600 #5 Secondary 122.00' 8.0' long x 6.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.501 Coef. (English) 2.37 2.51 2.70 2.68 2.68 2.67 2.65 2.65 2.65 2.65 2.66 2.66 2.67 2.69 2.72 2.76 2.83 Discarded OutFlow Max=0.02 cfs @ 12.46 hrs HW=120.21' (Free Discharge) t2=Exfiltration (FAItration Controls 0.02 cfs) Primary OutFlow Max=1.32 cfs @ 12.46 hrs HW=120.21' TW=0.00' (Dynamic Tailwater) LIvert (Passes 1.32 cfs of 8.63 cfs potential flow) 3-Orifice/Grate (Orifice Controls 1.32 cfs @ 6.75 fps) � Orifice/Grate ( Controls 0.00 cfs) econdary OutFlow Max=0.00 cfs @ 0.00 hrs HW=117.00' TW=0.00' (Dynamic Tailwater) =Broad-Crested Rectangular Weir ( Controls 0.00 cfs) Summary for Pond 152P: Detention Pond 3 Inflow Area = 57,305 sf, 37.42% Impervious, Inflow Depth = 2.72" for 10 yr event Inflow - 3.99 cfs @ 12.09 hrs, Volume= 12,984 cf Outflow - 1.50 cfs @ 12.36 hrs, Volume= 12,517 cf, Atten= 63%, Lag= 16.3 min Discarded 0.02 cfs @ 12.36 hrs, Volume= 1,940 cf Primary 1.48 cfs @ 12.36 hrs, Volume= 10,577 cf Secondary= 0.00 cfs @ 0.00 hrs, Volume= 0 cf Routing by Dyn-Stor-Ind method, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs/3 I Proposed Condition Watershed Analysis - Revised 8/31/2015-The Woodlands - Salem MA ' proposed-SUBMITTAL_R Type 111 24-hr 10 yr Rainfall=4.50" Prepared by Microsoft Printed 9/18/2015 HydroCAD® 10.00-15 s/n 06611 @2015 HydroCAD Software Solutions LLC Page 18 , Peak Elev= 116.60' @ 12.36 hrs Surf.Area= 3,311 sf Storage= 4,401 cf Flood Elev= 136.50' Surf.Area= 5,400 sf Storage= 12,340 cf Plug-Flow detention time= 148.3 min calculated for 12,517 cf(96% of inflow) Center-of-Mass det. time= 127.5 min ( 938.0 - 810.4 ) Volume Invert Avail.Storage Storage Description #1 115.00' 12,340 cf Custom Stage Data (Prismatic) Listed below(Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 115.00 2,200 0 0 116.00 2,870 2,535 2,535 ' 117.00 3,600. 3,235 5,770 118.00 4,560 4,080 9,850 118.50 5,400 2,490 12,340 Device Routing Invert Outlet Devices #1 Primary 113.50' 12.0" Round Culvert L= 10.0' CPP, square edge headwall, Ke= 0.500 Inlet/Outlet Invert= 113.50'/ 113.00' S= 0.0500 ? Cc= 0.900 n= 0.010, Flow Area= 0.79 sf #2 Device 1 115.50' 8.0"Vert. Orifice/Grate C= 0.600 ' #3 Secondary 118.00' 8.0' long x 6.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Coef. (English) 2.37 2.51 2.70 2.68 2.68 2.67 2.65 2.65 2.65 2.65 2.66 2.66 2.67 2.69 2.72 2.76 2.83 #4 Discarded 115.00' 0.270 in/hr Exfiltration over Surface area Discarded OutFlow Max=0.02 cfs @ 12.36 hrs HW=116.60' (Free Discharge) t4=Exfiltration (Exfiltration Controls 0.02 cfs) Primary OutFlow Max=1.47 cfs @ 12.36 hrs HW=116.60' TW=0.00' (Dynamic Tailwater) t-- =Culvert (Passes 1.47 cfs of 6.10 cfs potential flow) 2=Orifice/Grate (Orifice Controls 1.47 cfs,@ 4.22 fps) Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=115.00' TW=0.00' (Dynamic Tailwater) 3=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) ' Summary for Link 109L: Total Surface Runoff discharging from project area Inflow Area = 751,980 sf, 20.55% Impervious, Inflow Depth = 2.09" for 10 yr event Inflow = 23.32 cfs @ 12.17 hrs, Volume= 130,683 cf Primary = .23.32 cfs @ 12.17 hrs, Volume= 130,683 cf, Atten= 0%, Lag= 0.0 min Primary outflow= Inflow, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs ' ' Proposed Condition Watershed Analysis - Revised 8/31/2015-The Woodlands -.Salem MA proposed-SUBMITTAL_R Type Ill 24-hr 10 yr Rainfall=4.50" Prepared by Microsoft Printed 9/18/2015 HydroCAD®10.00-15 s/n 06611 @2015 HydroCAD Software Solutions LLC Page 19 Summary for Link 128L: Runoff towards existing wetlands to the north Inflow Area = 315,936 sf, 19.88% Impervious, Inflow Depth = 2.11" for 10 yr event Inflow 9.04 cfs @ 12.19 hrs, Volume= 55,488 cf Primary = 9.04 cfs @ 12.19 hrs, Volume= 55,488 cf, Atten= 0%, Lag= 0.0 min Primary outflow= Inflow, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs .Summary for Link 130L: Runoff towards Isolated Wetland "B" series Inflow Area = 70,668 sf, 4.80% Impervious, Inflow Depth = 1.82" for 10 yr event Inflow = 2.60 cfs @ 12.21 hrs, Volume= 10,720 cf Primary = 2.60 cfs @ 12.21 hrs, Volume= 10,720 cf, Atten= 0%, Lag= 0.0 min Primary outflow= Inflow, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs ' Summary for Link 132L: Runoff towards Clark Avenue Drainage System Inflow Area = 123,289 sf, 42.07% Impervious, Inflow Depth = 2.46" for 10 yr event Inflow 8.11 cfs @ 12.08 hrs, Volume= 25,295 cf Primary = 8.11 cfs @ 12.08 hrs, Volume= 25,295 cf, Atten= 0%, Lag= 0.0 min Primary outflow= Inflow, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs Summary for Link 139L: Runoff towards existing wetlands to the south Inflow Area = 436,044 sf, 21.03% Impervious, Inflow Depth = 2.07" for 10 yr event ' Inflow 14.80 cfs @ 12.12 hrs, Volume= 75,195 cf i Primary 14.80 cfs @ 12.12 hrs, Volume= 75,195 cf, Atten= 0%, Lag= 0.0 min Primary outflow= Inflow, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs I ' Summary for Link 141 L: Runoff towards Isolated Wetland "C" series Inflow Area = 49,862 sf, 0.00% Impervious, Inflow Depth = 1.67" for 10 yr event Inflow 1.74 cfs @ 12.18 hrs, Volume= 6,955 cf i Primary = 1.74 cfs @ 12.18 hrs, Volume= 6,955 cf, Atten= 0%, Lag= 0.0 min ' Primary outflow= Inflow, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs I Proposed Condition Watershed Analysis - Revised 8/31/2015-The Woodlands - Salem MA proposed-SUBMITTAL_R Type lil 24-hr 100 yr Rainfall=6.50" Prepared by Microsoft Printed 9/18/2015 HydroCAD®10.00-15 s/n 06611 @2015 HydroCAD Software Solutions LLC Page 20 Summary for Subcatchment 80$: PR-CB O+ORT [49] Hint: Tc<2dt may require smaller dt Runoff = 0.69 cfs @ 12.07 hrs, Volume= 2,268 cf, Depth= 5.45" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs ' Type III 24-hr 100 yr Rainfall=6.50" Area (so CN Description 375 98 Unconnected roofs, HSG C 1,515 74 >75% Grass cover, Good, HSG C 3,107 98 Paved parking, HSG C 4,997 91 Weighted Average 1,515 30.32% Pervious Area 3,482 69.68% Impervious Area ' . 375 10.77% Unconnected Tc Length Slope Velocity Capacity Description ' (min) (feet) (ft/ft) (ft/sec) (cfs) 3.3 25 0.0200 0.13 Sheet Flow, Grass: Short n= 0.150 P2= 3.10" 0.1 15 0.0312 3.59 Shallow Concentrated Flow, Paved Kv= 20.3 fps 0.6 165 0.0500 4.54 Shallow Concentrated Flow, Paved Kv= 20.3 fps ' 4.0 205 Total, Increased to minimum Tc = 5.0 min Summary for Subcatchment 81 S: PR-CB O+OLT ' [49] Hint: Tc<2dt may require smaller dt Runoff = 1.03 cfs @ 12.07 hrs, Volume= 3,202 cf, Depth= 4.34" ' Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs Type III 24-hr 100 yr Rainfall=6.50" Area (so CN Description ' 375 70 Woods, Good, HSG C 3,751 74 >75% Grass cover, Good, HSG C 3,023 98 Paved parking, HSG C 1,700 70 Woods, Good, HSG C ' 8,849 81 Weighted Average 5,826 65.84% Pervious Area 3,023 34.16% Impervious Area 1 Proposed Condition Watershed Analysis - Revised 8/31/2015-The Woodlands - Salem MA ' proposed-SUBMITTAL_R Type ll/24-hr 100 yr Rainfall=6.50" Prepared by Microsoft Printed 9/18/2015 HydroCAD®10.00-15 s/n 06611 @2015 HydroCAD Software Solutions LLC Page 21 Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (f/sec) (cfs) ' 3.3 . 25 0.0200 0.13 Sheet Flow, Grass: Short n= 0.150 P2= 3.10" 0.1 15 0.0312 3.59 Shallow Concentrated Flow, ' Paved Kv= 20.3 fps 0.6. 160 0.0500 4.54 Shallow Concentrated Flow, Paved Kv= 20.3 fps 4.0 200 Total, Increased to minimum Tc = 5.0 min ' Summary for Subcatchment 111 S: EX-1 R ' Runoff = 13.56 ofs @ 12.19 hrs, Volume= 53,957 cf, Depth= 3.41" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs ' Type III 24-hr 100 yr Rainfall=6.50" Area (so CN Description 141,864 70 Woods, Good, HSG C 37,700 74 >75% Grass cover, Good, HSG C 6,000 98 Unconnected.roofs, HSG C 4,490 91 Rip rap slope, HSG C 190,054 72 Weighted Average 184,054 96.84% Pervious Area 6,000 3.16% Impervious Area 6,000 100.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (f/sec) (cfs) 12.5 100 0.0800 0.13 Sheet Flow, Woods: Light underbrush n= 0.400 P2= 3.10" 0-4 100 0.0800 4.55 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 0:7 275 0.1500 6.24 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 13.6 475 Total Summary for Subcatchment 136S: EX-4R Runoff = 4.97 cfs @ 12.20 hrs, Volume= 20,063 cf, Depth= 3.41" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs Type III 24-hr 100 yr Rainfall=6.50" i 1 i i Proposed Condition Watershed Analysis - Revised 8/31/2015-The Woodlands - Salem MA ' proposed-SUBMITTAL_R Type 111 24-hr 100 yr Rainfall=6.50" Prepared by Microsoft Printed 9/18/2015 HydroCAD@ 10.00-15 s/n 06611 @2015 HydroCAD Software Solutions LLC Page 22 Area (so CN Description 51,513 70 Woods, Good, HSG C 2,250 98 Unconnected roofs, HSG C 1,142 98 Unconnected pavement, HSG C 15,763 74 >75% Grass cover, Good, HSG C 70,668 72 Weighted Average 67,276 95.20% Pervious Area 3,392 4.80% Impervious Area 3,392 100.00% Unconnected Tc Length Slope Velocity Capacity .Description (min) (feet) (ft/ft) (ft/sec) (cfs) , 12.5 100 0.0800 0.13 Sheet Flow, Woods: Light underbrush n= 0.400 P2= 3.10" 0.4 100 0.0800 4.55 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps ' 1.3 220 0.0300 2.79 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 14.2 420 Total Summary for Subcatchment 137S: EX-2r [49] Hint: Tc<2dt may require smaller dt Runoff = 1.35 cfs @ 12.08 hrs, Volume 4,169 cf, Depth= 3.71" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs Type III 24-hr 100 yr Rainfall=6.50" Area (so CN Adj Description 500 70 Woods, Good, HSG C . 375 98 Unconnected roofs, HSG C 1,240 98 Unconnected pavement, HSG C 11,363 74 >75% Grass cover, Good, HSG C 13,478 77 75 Weighted Average, UI Adjusted ' 11,863 88.02% Pervious Area 1,615 11.98% Impervious Area 1,615 100.00% Unconnected ' Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 3.3 50 0.0800 0.25 Sheet Flow, ' Grass: Short n= 0.150 P2= 3.10" 0.5 100 0.0400 3.22 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 0.6 95 0.0260 2.60 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 0.1 35 0.1100 5.34 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 4.5 280 Total, Increased to minimum Tc = 5.0 min Proposed Condition Watershed Analysis - Revised 8/31/2015- The Woodlands - Salem MA proposed-SUBMITTAL_R Type l/l 24-hr 100 yr Rainfall=6.50" Prepared by Microsoft Printed 9/18/2015 HydroCAD@ 10.00-15 s/n 06611 @2015 HydroCAD Software Solutions LLC Page 23 Summary for Subcatchment 138S: EX-3R Runoff = 12.88 cfs @ 12.22 hrs, 'Volume= 53,839 cf, Depth= 3.31" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs ' Type III 24-hr 100 yr Rainfall=6.50" Area (so CN Description 400 81 1/3 acre lots, 30% imp, HSG C 159,236 70 Woods, Good, HSG C 3,750 98 Unconnected roofs, HSG C 32,000 74 >75% Grass cover, Good, HSG C 1.95,386 71 Weighted Average 191,516 98.02% Pervious Area 3,870 1.98% Impervious Area ' 3,750 . 96.90% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 14.8 100 0.0530 0.11 Sheet Flow, Woods: Light underbrush n= 0.400 P2= 3.10" 0.5 180 0.1700 . 6.64 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 0.3 45 0.0200 2.28 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps ' 15.6 325 Total Summary for Subcatchment 14OS: EX-5 (No Change) Runoff = 3.47 cfs @ 12.17 hrs, Volume= 13,326 cf, Depth= 3.21" ' Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs Type III 24-hr 100 yr Rainfall=6.50" Area (sf) CN Description 49,862 70 Woods, Good, HSG C 49,862 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 100 0.1400 0.17 Sheet Flow, Woods: Light underbrush n= 0.400 P2= 3.10" i 0.3 100 0.1400 6.02 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 2.0 360 0.0360 3.05 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 12.3 560 Total Proposed Condition Watershed Analysis - Revised 8/31/2015-The Woodlands - Salem MA ' proposed-SUBMITTAL_R Type 11124-hr 100 yr Rainfall=6.50" Prepared by Microsoft Printed 9/18/2015 HydroCAD®10.00-15 s/n 06611 ©2015 HydroCAD Software Solutions LLC Page 24 Summary for Subcatchment 142S: PR- POND 2 [49] Hint: Tc<2dt may require smaller dt Runoff = 1.45 cfs @ 12.08 hrs, Volume= 4,474 cf, Depth= 3.71" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs , Type III 24-hr 100 yr Rainfall=6.50" Area (sf) CN Description 13,712 74 >75% Grass cover, Good, HSG C 750 98 Unconnected roofs, HSG C 14,462 75 Weighted Average 13,712 94.81% Pervious Area 750 5.19% Impervious Area 750 100.00% Unconnected ' Tc Length Slope Velocity Capacity Description (min) (feet) (f 1ft) (ft/sec) (cfs) ' 3.5 50 0.0700 0.24 Sheet Flow, Grass: Short n= 0.150 P2= 3.10" 0.1 20 0.0700 4.26 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 0.0 15 0.3300 9.25 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 3.6 85 Total, Increased to minimum Tc = 5.0 min Summary for Subcatchment 143S: PR-POND 1 [49) Hint: Tc<2dt may require smaller dt Runoff = 4.31 cfs @ 12.08 hrs, Volume= 13,340 cf, Depth= 3.71" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-40.00 hrs, dt= O.d5 hrs Type III 24-hr 100 yr Rainfall=6.50" Area (so CN Adi Description 4,125 98 Unconnected roofs, HSG C 33,998 74 >75% Grass cover, Good, HSG C 5,000 70 Woods, Good, HSG C 43,123 76 75 Weighted Average, UI Adjusted . 38,998 90.43% Pervious Area ' 4,125 9.57% Impervious Area 4,125 100.00% Unconnected Proposed Condition Watershed Analysis - Revised 8/31/2015- The Woodlands -Salem MA proposed-SUBMITTAL_R Type ll/24-hr 100 yr Rainfall=6.50" Prepared by Microsoft . Printed 9/18/2015 HydroCAD® 10.00-15 s/n 06611 @2015 HydroCAD Software Solutions LLC Page 25 Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) ' 3.8 50 0.0550 0.22 Sheet Flow, Grass: Short n= 0.150 P2= 3.10" 1.1 170 0.0250 2.55 Shallow Concentrated Flow, ' Unpaved Kv= 16.1 fps 0.1 65 0.3300 9.25 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 5.0 285 Total tSummary for Subcatchment 144S: PR-CB 1+65 RT ' [49] Hint: Tc<2dt may require smaller dt Runoff = 1.05 cfs @ 12.07 hrs, Volume= 3,364 cf, Depth= 5.11" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs Type III 24-hr 100 yr Rainfall=6.50" Area (so CN Description 1,125 98 Unconnected roofs, HSG C 3,458 98 Paved parking, HSG C 3,319 74 >75% Grass cover, Good, HSG C 7,902 88 Weighted Average 3,319 42.00% Pervious Area 4,583 58.00% Impervious Area 1,125 24.55% Unconnected ' Tc Length Slope Velocity Capacity Description (min) (feet) . (f/ft) (ft/sec) (cfs) 3.3 25 0.0200 0.13 Sheet Flow, Grass: Short n= 0.150 P2= 3.10" 0.0 10 0.0312 3.59 Shallow Concentrated Flow, Paved Kv= 20.3 fps ' 0.6 165 0.0500 4.54 Shallow Concentrated Flow, Paved Kv= 20.3 fps 3.9 200 Total, Increased to minimum Tc = 5.0 min Summary for Subcatchment 145S: PR-CB 3+50LT [49] Hint: Tc<2dt may require smaller dt Runoff 2.20 cfs @ 12.08 hrs, Volume= 7,188 cf, Depth= 5.22" ' Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs Type III 24-hr 100 yr Rainfall=6.50" t ■ Proposed Condition Watershed Analysis - Revised 8/31/2015-The Woodlands -Salem MA proposed-SUBMITTAL-111 Type 11124-hr 100 yr Rainfall=6.50" Prepared by Microsoft Printed 9/18/2015 HydroCAD®10.00-15 s/n 06611 @2015 HydroCAD Software Solutions LLC Page 26 Area (sf) CN Description 2,625 98 Unconnected roofs, HSG C 7,358 98 Paved parking, HSG C 6,539 74 >75% Grass cover, Good, HSG C 16,522 89 Weighted Average 6,539 39.58% Pervious Area ' 9,983 60.42% Impervious Area 2,625 26.29% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 3.6 20 0.0100 0.09 Sheet Flow, , Grass: Short n= 0.150 P2= 3.10" 0.0 10 0.0312 3.59 Shallow Concentrated Flow, Paved Kv= 20.3 fps 1.7 285 0.0200 2.87 Shallow Concentrated Flow, Paved Kv= 20.3 fps 5.3 315 Total Summary for Subcatchment 146S: PR-CB 3+50RT , [49] Hint: Tc<2dt may require smaller dt Runoff = 1.85 cfs @ 12.07 hrs, Volume= 6,044 cf, Depth= 5.45" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs ' Type III 24-hr 100 yr Rainfall=6.50" Area (so CN Description - t 2,625 98 Unconnected roofs, HSG C 6,914 98 Paved parking, HSG C 3,775 74 >75% Grass cover, Good,.HSG C 13,314 91 Weighted Average 3,775 28.35% Pervious Area 9,539 71.65% Impervious Area 2,625 27.52% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 2.9 15 0.0100 0.09 Sheet Flow, Grass: Short n= 0.150 P2= 3.10" 0.0 10 0.0312 3.59 Shallow Concentrated Flow, Paved Kv= 20.3 fps 1.7 285 0.0200 2.87 Shallow Concentrated Flow, Paved Kv=20.3 fps , 4.6 310 Total, Increased to minimum Tc = 5.0 min . ' Proposed Condition Watershed Analysis - Revised 8/31/2015-The Woodlands - Salem MA proposed-SUBMITTAL, R Type 111 24-hr 100 yr Rainfall=6.50" Prepared by Microsoft Printed 9/18/2015 HydroCAD@ 10.00-15 s/n 06611 @2015 HydroCAD Software Solutions LLC Page 27 Summary for Subcatchment 147S: PR-CB 1+65 LT [49] Hint: Tc<2dt may require smaller dt Runoff = 1.22 cfs @ ,12.07.hrs, Volume= 3,933 cf, Depth= 5.22" ' • Runoff by SCS TR-20 method, UH=SCS; Weighted-CN, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs Type III 24-hr 100 yr Rainfall=6.50" Area (so CN Description 1,500 98 Unconnected roofs, HSG C 4,314 98 Paved parking, HSG C 3,225 74 , >75% Grass cover, Good HSG C 9,039 89, Weighted Average 3,225 35.68% Pervious Area ' 5,814 64.32% Impervious Area 1,500 25.80% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (f/sec) (cfs) 3.3 25 0.0200 0.13 Sheet Flow, Grass: Short n= 0.150 P2= 3.10" 0.0 10 0.0312 3.59 Shallow Concentrated Flow, Paved Kv= 20.3 fps '0.6 165 0.0500 4.54 Shallow Concentrated Flow, Paved Kv= 20.3 fps 3.9 200 Total, Increased to minimum Tc = 5.0 min Summary for Subcatchment 148S: 3/4 roof area Lot 12 [49] Hint: Tc<2dt may require smaller dt �. Runoff = 0.1Tcfs @ 12.07 hrs, Volume= 587 cf, Depth= 6.26" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs Type III 24-hr 100 yr Rainfall=6.50" Area (so CN Description •� 1,125 98 Roofs, HSG C 1,125 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 1.0 Direct Entry, • 1.0 0 Total, Increased to minimum Tc = 5.0 min Proposed Condition Watershed Analysis - Revised 8/31/2015-The Woodlands - Salem MA proposed-SUBMITTAL_R Type 111 24-hr 100 yr Rainfall=6.50" Prepared by Microsoft Printed 9/18/2015 HydroCAD® 10.00-15 s/n 06611 @ 2015 HydroCAD Software Solutions LLC Page 28 Summary for Subcatchment 149S: EX-RES 1 r [49] Hint: Tc<2dt may require smaller dt Runoff = 11.97 cfs @ 12.07 hrs, Volume= 37,746 cf, Depth= 4.78" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs ' Type III 24-hr 100 yr Rainfall=6.50" Area (sf) CN Description ' 61,852 81 1/3 acre lots, 30% imp, HSG C 24,065 98 Paved parking, HSG C 7,317 74 >75% Grass cover, Good, HSG C 1,606 70 Woods, Good, HSG C 94,840 85 Weighted Average 52,219 55.06% Pervious Area 42,621 44.94% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 3.5 50 0.0700 0.24 Sheet Flow, Grass: Short n= 0.150 P2= 3.10" ' 0.3 100 0.1000 5.09 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 1.2 150 0.0100 2.03 Shallow Concentrated Flow, Paved Kv= 20.3 fps t 5.0 300 Total Summary for Subcatchment 15OS: PR-CB Road B ' Runoff = 4.14 cfs @ 12.09 hrs, Volume= 13,980 cf, Depth= 5.33" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-40.00 hrs,dt= 0.05 hrs Type III 24-hr 100 yr Rainfall=6.50" Area (so CN Description ' 3,750 98 -Unconnected roofs, HSG C 10,385 74 >75% Grass cover, Good, HSG C 17,318 98 Paved parking, HSG C 31,453 90 Weighted Average 10,385 33.02% Pervious Area 21,068 66.98% Impervious Area 3,750 17.80% Unconnected ' Proposed Condition Watershed Analysis - Revised 8/31/2015-The Woodlands - Salem MA proposed-SUBMITTAL R Type 111 24-hr 100 yr Rainfall=6.50" Prepared by Microsoft Printed 9/18/2015 HydroCAD®10.00-15 s/n 06611 @2015 HydroCAD Software Solutions LLC Page 29 ' Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) ' 4.3 35 0.0200 0.14 Sheet Flow, Grass: Short n= 0.150 P2= 3.10" 0.01 10 0.0312 3.59 Shallow Concentrated Flow, ' Paved Kv= 20.3 fps 2.2 270 0.0100 2.03 Shallow Concentrated Flow, Paved Kv= 20.3 fps 6.5 315 Total Summary for Subcatchment 151 S: PR-POND 3 ' [49] Hint: Tc<2dt may require smaller dt Runoff = .2.44 cfs @ 12.08 hrs, Volume= 7,557 cf, Depth= 3.51" ' Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs Type III 24-hr 100 yr Rainfall=6.50" Area (so CN Ad* Description 375 98 Unconnected roofs, HSG C ' 20,077 74 >75% Grass cover, Good, HSG C 5,400 . 70 Woods, Good, HSG C 25,852 74 73 Weighted Average, UI Adjusted 25,477 98.55% Pervious Area 375 1.45% Impervious Area 375 100.00% Unconnected ' Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (f/sec) (cfs) 2.4 50 0.1700 0.34 Sheet Flow, ' Grass: Short n= 0.150 P2= 3.10" 0.3 115 0.1700 6.64 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 0.0 10 0.3300 9.25 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 2.7 175 Total, Increased to minimum Tc = 5.0 min Summary for Subcatchment 152S: PR-CB 9+50LT [49] Hint: Tc<2dt may require smaller dt ' Runoff = 1.96 cfs @ 12.07 hrs, Volume= 6,416 cf, Depth= 5.45" ' Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs Type III 24-hr 100 yr Rainfall=6.50" 1 Proposed Condition Watershed Analysis - Revised 8/31/2015-The Woodlands - Salem MA ' proposed-SUBMITTAL_R Type 11124-hr 100 yr Rainfall=6.50" Prepared by Microsoft Printed 9/18/2015 HydroCAD@ 10.00-15 s/n 06611 @2015 HydroCAD Software Solutions LLC Page 30 ' Area (so CN Description 2,625 98 Unconnected roofs, HSG C 4,401 74 >75% Grass cover, Good, HSG C 7,107 98 Paved parking, HSG C 14,133 91 Weighted Average 4,401 31.14% Pervious Area ' 9,732 68.86% Impervious Area 2,625 26.97% Unconnected Tc Length Slope Velocity Capacity Description ' (min) (feet) (ft/ft) (ft/sec) (cfs) 3.3 25 0.0200 0.13 Sheet Flow, Grass: Short n= 0.150 P2= 3.10" 0.0 10 0.0312 3.59 Shallow Concentrated Flow, Paved Kv= 20.3 fps 1.7 260 0.0160 2.57 Shallow Concentrated Flow, Paved Kv= 20.3 fps 5.0 295 Total Summary for Subcatchment 153S: PR-CB 10+84 ' [49] Hint: Tc<2dt may require smaller dt ' Runoff = 2.19 cfs @ 12.07 hrs, Volume= 7,227 cf, Depth= 5.56" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs ' Type III 24-hr 100 yr Rainfall=6.50" Area (sf) . CN Description 1,875 98 Unconnected roofs, HSG C 3,834 74 >75% Grass cover, Good, HSG C 9,884 98 Paved parking, HSG C t 15,593 92 Weighted Average 3,834 24.59% Pervious Area 11,759 75.41% Impervious Area ' 1,875 15.95% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) ' 3.3 25 0.0200 0.13 Sheet Flow, Grass: Short n= 0.150 P2= 3.10" 0.0 10 0.0312 3.59 Shallow Concentrated Flow, ' Paved Kv= 20.3 fps 1.1 165 0.0160 2.57 Shallow Concentrated Flow, Paved Kv= 20.3 fps ' 4.4 200 Total, Increased to minimum Tc = 5.0 min ' Proposed Condition Watershed Analysis - Revised 8/31/2015-The Woodlands - Salem MA proposed-SUBMITTAL R Type 111.24-hr 100 yr Rainfall=6.50:" Prepared by Microsoft Printed 9/18/2015 HydroCAD@ 10.00-15 s/n 06611 @2015 HydroCAD Software Solutions LLC Page 31 ' ' Summary for Subcatchment 154S: PR-CB 9+50RT [49] Hint: Tc<2dt may require smaller dt Runoff = 2.20 cfs @ 12.07 hrs, Volume= 7,091 cf, Depth= 5.22" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs Type III 24-hr 100 yr Rainfall=6.50" Area (so CN Description 1,875 98 Unconnected roofs, HSG C 6,425 74 >75% Grass cover, Good, HSG C ' 7,998 98 Paved parking, HSG C 16,298 89 Weighted Average 6,425 39.42% Pervious Area 9,873 60.58% Impervious Area 1,875 18.99% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (f 1sec) (cfs) 2.7 40 0.0800 0.24 Sheet Flow, ' Grass: Short n= 0.150 P2=.3.10" 0.0 10 0.0312 3.59 Shallow Concentrated,Flow, Paved Kv= 20.3 fps 1.8 280 0.0160 2.57 Shallow Concentrated Flow, Paved Kv= 20.3 fps 4.5 330 Total, Increased to minimum Tc = 5.0 min Summary for Subcatchment 155S: EX-RES 2R [49] Hint: Tc<2dt may require smaller dt ' Runoff = 1.59 cfs @ 12.07 hrs, Volume= 4,915 cf, Depth= 4.24" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs Type III 24-hr 100 yr Rainfall=6.50". Area (so CN Description ' 12,285 81 1/3 acre lots, 30% imp, HSG C 1,640 70 Woods, Good, HSG C 13,925 80 Weighted Average ' 10,240 73.53% Pervious Area 3,686 26.47% Impervious Area t 1 Proposed Condition Watershed'Analysis - Revised 8/31/2015-The Woodlands - Salem MA , proposed-SUBMITTAL_R Type 111 24=hr 100 yr Rainfall=6.50": Prepared by Microsoft Printed .9/18/2015 HydroCADO 10.00-15 s/n 06611 ©2015 HydroCAD Software Solutions LLC Paoe'32 ' Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 4.3 50 0.0400 0.19 Sheet Flow, ' Grass: Short n= 0.150 P2= 3.10" 0.4 55 0.0200 2.28 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps ' 4.7 105 Total, Increased to minimum Tc = 5.0 min Summary for Subcatchment 156S: PR-POND 4 ' [49] Hint: Tc<2dt may require smaller dt Runoff = 2.39 cfs @ 12.08 hrs, Volume= 7,445 cf, Depth= 4.13". i Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs ' Type III 24-hr 100 yr Rainfall=6.50" Area (sf) CN Description 1,500 98 Unconnected roofs, HSG C ' .15,295 74 >75% Grass cover, Good, HSG C 4,840 91 Rip Rap, HSG C 21,635 79 Weighted Average 20,135 93.07% Pervious Area 1,500 6.93% Impervious Area 1,500 1.00.00% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet). (f/ft) (ft/sec) (cfs)' 2.6 50 0.1500 0.33 Sheet Flow; ' Grass: Short n= 0.150 P2= 3.10" 0.1 20 0.1200 5.58 Shallow Concentrated Flow, . Unpaved Kv= 16.1 fps 0.1 30 0.3300 9.25 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 0.0 25 0.3300 9.25 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps. 2.8 125 Total, Increased to minimum Tc = 5.0 min Summary for Pond.78P: Proposed CULTEC 330XL (infiltration System #1) [93] Warning: Storage range exceeded by 1.97' ' [87] Warning: Oscillations may require smaller dt or Finer Routing (severity=113) Inflow Area = 14,971 sf, 50.97% Impervious, Inflow Depth = 4.86" for 100 yr event Inflow = 1.89 cfs @ 12.07 hrs, Volume= 6,057 cf Outflow = 0.70 cfs @ 12.50 hrs, Volume= 3,230 cf, Atten= 63%, Lag= 25.5 min Discarded = 0.01 cfs @ 8.05 hrs, Volume= 1,187 cf Secondary= 0.69 cfs @ 12.50 hrs, Volume= 2,043 cf ' ' I! ProposedCondition Watershed'Analysis - Revised 8/31/2015-The Woodlands - Salem MA ' proposed-SUBMITTAL, R Type Ill 24-hr 100 yr Rainfall=6.50" Prepared by Microsoft Printed 9/18/2015 HroCAD®10.00-15.s/n 06611 @2015 HydroCAD Software Solutions LLC Page 33 ' Routing by Dyn-Stor-Ind method, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs/ 3 Peak Elev=127.91' @ 12.50 hrs Surf.Area= 1,489 sf Storage= 3,361 cf Plug-Flow detention time= 392.8 min calculated for 3,226 cf(53% of inflow) Center-of-Mass det. time= 282.0 min ( 1,072.1 - 790.1 ) Volume Invert Avail.Storage Storage Description #1A 122.40' 1,274 cf 25.67'W x 58.001 x 3.54'H Field A 5,272 cf Overall =2,086 cf Embedded = 3,186 cf x 40.0% Voids t #2A 122,90' 2,086 cf Cultec R-330XL x 40 Inside#1 Effective Size= 47.8'W x 30.0"H => 7.45 sf x 7.001 = 52.2 cf Overall•Sizg= 52.0"W x 30.5"H x 8.501 with 1.50' Overlap 5 Rows of 8 Chambers ' 3,361 cf Total Available Storage ' Storage Group A created with Chamber Wizard Device Routing Invert Outlet Devices #1 Discarded 122.40' 0.270 in/hr Exfiltration over Surface area #2 . Secondary 127.75' .4.0' long x 1.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 Coef. (English) 2.69 2.72 2.75 2.85 2.98 3.08 3.20 3.28 3.31 ='. 3.30 3.31 3.32 Discarded OutFlow.M6x=0.01 cfs @ 8.05 hrs HW=122.46' (Free Discharge) L1=Exfiltration (Exfiltration Controls 0.01 cfs) SecondaryOutFlow Max=0.65 cfs @•12.50.hrs HW=127.90' TW=0.00' (Dynamic Tailwater) ' 2=Bread-Crested•Rectangular Weir (Weir Controls 0.65 cfs @ 1.06 fps) Summary for Pond 14213: Detention Pond 1 Inflow Area = 60,064 sf, 24.18% Impervious, Inflow Depth = 4.12" for 100 yr event •'Inflow = 6.56 cfs @ 12.08,hrs, Volume= 20,636 cf Outflow = 4107 cfs@ • 12.18 hrs, Volume=, 20,315 cf, Atten= 38%, Lag= 6.3 min ' -Discarded = .0.02.cfs @ 12.18 hrs, Volume= 817 cf 'Primary = 4.05'cfs @ '12.18 hrs, Volume= 19,498 cf . Secondary = 0.00 cfs @ 0.00 hrs, Volume= 0 cf Routing by Dyn-Stor-Ind method, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs/ 3 Peak'Elev= 135.34' @ 12.18 hrs Surf.Area= 2,449 sf Storage= 4,851 cf Flood Elev='136.50' Surf.Area= 3,660 sf Storage= 8,258 cf . 1 1 . Plug-Flow detention time= 66.2 min calculated for 20,289 cf(98% of inflow) Center-of-Mass det. time= 57.8 min ( 867.1 - 809.3 ) Proposed Condition Watershed Analysis - Revised 8/31/2015-The Woodlands -Salem MA ' proposed-SUBMITTAL_R - Type Ill 24-hr 100 yr Rainfall=6.50" Prepared by Microsoft Printed 9/18/2015 HydroCAD®10.00-15 s/n 06611 @2015 HydroCAD Software Solutions LLC Page 34 ' Volume Invert Avail.Storage Storage Description #1 132.00' 8;258 cf Custom Stage Data (Prismatic) Listed below(Recalc) ' Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 132.00 600 0 0 ' 133.00 1,060 830 830 134.00 1,590 1,325 2,155 135.00 2,210 1,900 4,055 ' 136.00 2,910 2,560 6,615 136.50 3,660 1,643 8,258 Device Routing Invert Outlet Devices ' #1 Primary 131.50' 12.0" Round Culvert L=.175.0' CPP, square edge headwall, Ke= 0.500 Inlet/Outlet Invert= 131.50' / 129.75' S= 0.0100 'P Cc= 0.900 ' n= 0.010, Flow Area= 0.79 sf #2 ' Device 1 132.75' 4.0"Vert. Orifice/Grate C= 0.600 #3. Device 1 134.00' 8.0"Vert. Orifice/Grate C= 0.600 ' 44 . Device 1 134.50' 10.0" Vert. Orifice/Grate C= 0.600 #5 Secondary 136.00` 8.0' long.'x 6.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 ' 2.50 3.00 3.50 4.00 4.50 5.00 5.50 .Coef. (English) 2.37 2.51 2.70 2.68 2.68 2..67 2.65 2.65 2.65 2.65 2.66 2.66 2.67 2.69 2.72 2.76 2.83 #6 Discarded 132.00' 0.270 in/hr Exfiltration over Surface area iscarded OutFlow Max=0:02 cfs @ 12.18 hrs HW=135.33' (Free Discharge) Exfiltration (Exfiltration Controls 0.02 cfs) , Primary OutFlow. Max=4.03 ofs @ 12.18 hrs HW=135.33' TW=0.00' (Dynamic Tailwater) t =Culvert (Passes 4.03 cfs of 6.19 cfs potential flow) 2--Orifice/Grate (Orifice Controls 0.65 cfs @ 7.49 fps) ' 3=Orifice/Grate (Orifice Controls 1.68 cfs @ 4.82 fps) -Orifice/Grate (Orifice Controls 1.70 cfs @ 3.11 fps) econdary OutFlow Max=0.00 cfs.@ 0.00 hrs HW=132.00' TW=0.00' (Dynamic Tailwater) ' Broad-Crested Rectangular Weir ( Controls 0.00 cfs) Summary for Pond 143P: Detention Pond 2 , Inflow Area 44,298 sf, 45.76% Impervious, Inflow Depth = 4.80" for 100 yr event ' Inflow = .5.47 cfs @ 12.08 hrs, Volume= 17,706.cf Outflow = 0.29 cfs @ 14.19 hrs, Volume= 16,823 cf, Atten= 95%, Lag= 127.0 min Discarded = 0.03 cfs @ 14.19 hrs, Volume= 2,514 cf Primary = 0.26 cfs @ 14.19 hrs, Volume= 14,309 cf , Secondary= 0.00•cfs @ 0.00 hrs, Volume= 0 cf Routing by Dyn-Stor-Ind method, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs/ 3 ' ' Proposed Condition Watershed Analysis - Revised 8/31/2015- The Woodlands - Salem MA proposed-SUBMITTAL R Type M 24-hr 100 yr Rainfall=6.50" Prepared by Microsoft Printed 9/18/2015 . HydroCAD® 10.00-15 s/n 06611 @2015 HvdroCAD Software Solutions LLC Page 35 ' Peak Elev= 131.20' @ 14.19 hrs Surf.Area= 4,514 sf Storage= 10,561 cf Flood Elev= 136.50' Surf.Area= 6,340 sf Storage= 17,293 cf tPlug-Flow detention time= 449.1 min calculated for 16,802 cf(95% of inflow) Center-of-Mass det. time= 421.9 min ( 1,213.7 - 791.8 ) . Volume Invert Avail.Storage Storage Description #1 128.00' . 17,293 cf Custom Stage Data (Prismatic) Listed below(Recalc) Elevation . Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 128.00 1,800 0 0 ' 128.50 2,560 1,090 1,090 129.00 2,890 1,363 2,453 130.00 3,590 3,240 5,693 ' 131.00 4,350 3,970 9,663 132.00 5,160 4,755 14,418 132.50 6,340 2,875 17,293 Device Routing Invert Outlet Devices #1 Primary 127.50' 12.0" Round Culvert L= 16.0' CPP, square edge headwall, Ke= 0.500 ' Inlet/Outlet Invert= 127.50'/ 127.00' S= 0.0313T Cc= 0.900 n= 0.010, Flow Area= 0.79 sf #2 Secondary 132.00' 8.0' long x 6.0' breadth Broad-Crested Rectangular Weir ' Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Coef. (English) 2.37 2.51 2.70 2.68 2.68 2.67 2.65 2.65 2.65 ' 2.65 2.66 2.66 2.67 2.69 2.72 2.76 2.83 #3 Discarded 128.00' 0.270 in/hr Exfiltration over Surface area #4 Device 1 128.50' 2.5"Vert. Orifice/Grate C= 0.600 ' Discarded OutFlow Max=0.03 cfs @ 14.19 hrs HW=131.20' (Free Discharge) 3=Exfiltration (Exfiltration Controls 0.03 cfs) Primary OutFlow Max=0.26 cfs @ 14.19 hrs HW=131.20' TW=0.00' (Dynamic Tailwater) t-17-Culvert (Passes 0.26 cfs of 6.77 cfs potential flow) t,4=Orifice/Grate (Orifice Controls 0.26 cfs @ 7.76 fps) ' 2tecondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=128.00' TW=0.00' (Dynamic Tailwater) =Broad-Crested Rectangular Weir ( Controls 0.00 cfs) ' Summary for Pond 144P: Detention Pond 4 Inflow Area = 67,659 sf, 48.57% Impervious, Inflow Depth = 5.00" for 100 yr event Inflow 8.76 cfs @ 12.07 hrs, Volume= 28,178 cf Outflow 2.41 cfs @ 12.42 hrs, Volume= 27,447 cf, Atten= 72%, Lag= 20.9 min Discarded = 0.03 cfs @ 12.42 hrs, Volume= 1,330 cf ' Primary = 2.38 cfs @ 12.42 hrs, Volume= 26,117 cf Secondary = 0.00 cfs @ 0.00 hrs, Volume= 0 cf ! Proposed Condition Watershed Analysis - Revised 8/31/2015-The Woodlands -Salem MA proposed-SUBMITTAL_R Type 111 24-hr 100 yr Rainfall=6.50" Prepared by Microsoft Printed 9/18/2015 HydroCAD®10.00-15 s/n 06611 @2015 HydroCAD Software Solutions LLC Page 36' ' Routing by Dyn-Stor-Ind method, Time Span= 0.0040.00 hrs, dt= 0.05 hrs/3 Peak Elev= 121.06' @ 12.42 hrs Surf.Area= 4,561 sf Storage= 9,882 cf ' Plug-Flow detention time= 97.1 min calculated for 27,447 cf(97% of inflow) Center-of-Mass det. time= 81.4 min ( 869.1 - 787.6 ) ' Volume Invert Avail.Storage Storage Description #1 117.00' 18,006 cf Custom Stage Data (Prismatic) Listed below(Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 117.00 790 0 0 118.00 1,460 1,125 1,125 119.00 2,230 1,845 2,970 120.00 3,285 2,758 5,728 ' 121.00 4,480 3,883 9,610 122.00 5,825 5,153 14,763 122.50 7,150 3,244 18,006 , Device Routing Invert Outlet Devices #1 Primary 114.50' 12.0" Round Culvert L= 13.0' CPP, square edge headwall, Ke= 0.500 Inlet/Outlet Invert= 114.50'/ 114.00' S= 0.0385'P Cc= 0.900 n= 0.010,' Flow Area= 0.79 sf #2 Discarded 117.00' 0.270 in/hr Exfiltration over Surface area #3 Device 1 118.00' 6.0"Vert. Orifice/Grate C= 0.600 #4 Device 1 120.50' 8.0"Vert. Orifice/Grate C= 0.600 #5 Secondary 122.00' 8.0' long x 6.0' breadth Broad-Crested Rectangular Weir , Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Coef. (English) 2.37 2.51 2.70 2.68 2.68 2.67 2.65 2.65 2.65 2.65 2.66 2.66 2.67 2.69 2.72 2.76 .2.83 Discarded OutFlow Max=0.03 cfs @ 12.42 hrs 14W=121.06' (Free Discharge) t-2=Exfiltration (Exfiltration Controls 0.03 cfs) jPrimary OutFlow Mak=2.38 cfs @ 12.42 hrs HW=121.06' TW=0.00' (Dynamic Tailwater) t-I-Culvert (Passes 2.38 cfs of 9.31 cfs potential flow) U��-UOrifice/Grate (Orifice Controls 1.58 cfs @ 8.07 fps) ' -Orifice/Grate (Orifice Controls 0.79 cfs @ 2.54 fps) econdary OutFlow Max=0.00 cfs @ 0.00 hrs HW=117.00' TW=0.00' (Dynamic Tailwater) ' Broad-Crested Rectangular Weir ( Controls 0.00 cfs) t Proposed Condition Watershed Analysis - Revised 8/31/2015-The Woodlands - Salem MA proposed-SUBMITTAL-11 Type 111 24-hr 100 yr Rainfall=6.50" Prepared by Microsoft Printed 9/18/2015 HydroCAD® 10.00-15 s/n 06611 ©2015 HydroCAD Software Solutions LLC Page 37 Summary for Pond 152P: Detention Pond 3 ' Inflow Area = 57,305 sf, 37.42% Impervious, Inflow Depth = 4.51" for 100 yr event Inflow 6.56 cfs @ 12.09 hrs, Volume= 21,537 cf Outflow = 2.10 cfs @ 12.41 hrs, Volume= 21,049 cf, Atten= 68%, Lag= 19.0 min ' Discarded 0.02 cfs @ 12.41 hrs, Volume= 2,062 cf Primary 2.07 cfs @ 12.41 hrs, Volume= 18,987 cf Secondary = 0.00 cfs @ 0.00 hrs, Volume= 0 cf ' Routing by Dyn-Stor-Ind method, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs/3 Peak Elev= 117.35. @ 12.41 hrs Surf.Area= 3,938 sf Storage= 7,097 cf Flood Elev= 136.50' Surf.Area= 5,400 sf Storage= 12,340 cf ' Plug-Flow detention time= 109.4 min calculated for 21,023 cf(98% of inflow) Center-of-Mass det. time= 96.9 min ( 894.9 - 798.1 ) Volume Invert Avail.Storage Storage Description #1 115.00' 12,340 cf Custom Stage Data (Prismatic) Listed below(Recalc) ' Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 115.00 2,200 0 0 116.00 2,870 2,535 2,535 117.00 3,600 3,235 5,770 118.00 4,560 4,080 9,850 . 118.50 5,400 2,490 12,340 Device . Routing Invert Outlet Devices #1 Primary 113.50' 12.0" Round Culvert L= 10.0' CPP, square edge headwall, Ke= 0.500 Inlet/Outlet Invert= 113.50'/ 113.00' S= 0.0500T Cc= 0.900 n= 0.010, Flow Area= 0.79 sf ' #2 Device 1 115.50' 8.0"Vert. Orifice/Grate C= 0.600 #3 Secondary 1.18.00' 8.0' long.x 6.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Coef. (English) 2.37 2.51 2.70 2.68 2.68 2.67 2.65 2.65 2.65 2.65 2.66 2.66 2.67 2.69 2.72 2.76 2.83 #4 Discarded 115.00' 0.270 inthr Exfiltration over Surface area Iscarded OutFlow Max=0.02 cfs @ 12.41 hrs HW=117.35' (Free Discharge) Exfiltration (Exfiltration Controls 0.02 cfs) Primary OutFlow Max=2.07 cfs @ 12.41 hrs HW=117.35' TW=0.00' (Dynamic Tailwater) t Culvert (Passes 2.07 cfs of 6.92 cfs potential flow) -2-Orifice/Grate (Orifice Controls 2.07 cfs @ 5.93 fps) Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=115.00' TW=0.00' (Dynamic.Tailwater) ' 3=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) i Proposed Condition Watershed Analysis - Revised 8/31/2015=The Woodlands - Salem MA proposed-SUBMITTAL_R Type 11124-hr 100 yr Rainfall=6.50" Prepared by Microsoft Printed. 9/t8/2015 ., HydroCAD® 10.00-15 s/n 06611 ©2015 HydroCAD Software Solutions LLCPade,3fl ; Summary for Link 109L: Total Surface Runoff discharging!from project area Inflow Area = 751,980 sf, 20.55% Impervious, Inflow Depth = 3.76" for 100 yr event Inflow = 42.85 cfs @ 12.17 hrs, Volume= 235,581 cf Primary = 42.85 cfs @ 12.17 hrs, Volume= 235,581 cf, Atten= 0%, Lag= 0.0 min Primary outflow= Inflow, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs , Summary for Link 128L: Runoff towards existing wetlands to the north Inflow Area = 315,936 sf, 19.88% Impervious, Inflow Depth = 3.77" for 100 yr event Inflow = 16.57 cfs @ 12.19 hrs, Volume= 99,298 cf Primary = 16.57 cfs @ 12.19 hrs, Volume= 99,298 cf, Atten= 0%, Lag= 0.0 min - Primary outflow= Inflow, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs Summary for Link 130L: Runoff towards Isolated Wetland "B" series Inflow Area = 70,668 sf, 4.80% Impervious, Inflow Depth = 3.41" for 100 yr event , Inflow = 4.97 cfs @ 12.20 hrs, Volume= 20,063 cf Primary = 4.97 cfs @ 12.20 hrs, Volume= 20,063 cf, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs Summary for Link 132L: Runoff towards Clark Avenue Drainage System . Inflow Area 123,289 sf, 42.07% Impervious, Inflow Depth = 4.28" for 100 yr event Inflow = 13.33 cfs @ 12.07 hrs; Volume= 43,959 cf ' .. : Primary = 13.33 cfs @ 12.07 hrs,. Volume= 43,959 cf, Atten= 0%, Lag= 0.0 min Primary outflow= Inflow, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs .. ' Summary for Link 139L: Runoff towards existing wetlands to the south Inflow Area = 436,044 sf, 21.03% Impervious, Inflow Depth = 3.76" for A00 yr event Inflow = 27.44 cfs @ 12.12 hrs, Volume= 136,282 cf, Primary = 27.44 cfs @ 12.12 hrs, Volume= 136,282 cf, Atten= 0%, Lag= 0 0-min: Primary outflow= Inflow, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs ' Summary for Link 141 L: Runoff towards Isolated Wetland "C' series' Inflow Area = 49,862 sf, 0.00% Impervious, Inflow Depth = 3.21" for 100 yr event. Inflow = 3.47 cfs @ 12.17 hrs, Volume= 13,326 cf ' Primary = 3.47 cfs @ 12.17 hrs, Volume= 13,326 cf, Atteri= 0%, Lag= 0.0 min Primary outflow= Inflow, Time Span= 0.00-40.00 hrs, dt= 0.05 hrs 1 ■rm' f:?-Mriu�TTl7■/ .////A/■/■■■/../■■■ ■r■■ollm/mm/mm■iillG��sii.i�;�///.■../.■■■/ ■■■■■■.■■..■■..■■.■■■■../■//■........ ■..■■■.■/.■■■■■■.■■■■■■.■.■.//■/■.■/. oil o!"OEM■. 'EMOMENEEmr-"Pi CREW. .eco■■■■..■...■■■■■■■■■.■■■.■..■■.■■■. •••C■..■........Y�..■.P■■■■.■■■■■..■ON .. o■■.m■■u ■..■■■■..■. C3Eg3 l..■■■■.■■■■i moo■■■.■■mons■■■■■■.■■■■■■■■■.■■■■■■■■t 'WWii.e■!n■■ ■i■■1/■■■■W■■/ EtMEN■■■■■■■■■■■■■■■ ..•���ec���■�©�■e��■■■�■r.�-ewe■�o�i ■■� '! �■ �lGaR■ A'Elil �\■llC�:Tc C4■Ci"�; ■■i!!��.1�1�'�7©■i�1[:!'1����i��i■■ie�F���J�7�l��t .■■■r■■■■■■■■■■.■...■.%E�Q ■■ .■■■■■■■ .■■i�?lE�a,7!.1A■i►i��:��' i7k�i■■■■i�3�Z1F31■�it'� - ■■■■■■■■■■■■■■■e■■■.■■■■■■■■■■■■■■■■■. .............■....... ■■■■.■■■■■■■... .unu.0 nnmem■..� V INSTRUCTIONS: version t,Automated:Mar. 4,2008 1. In BMP Column, click on Blue Cell to Activate Drop Down Menu 2. Select BMP from Drop Down Menu 3. After BMP is selected, TSS Removal and other Columns are automatically completed. Y`�.'.. . . L��; Location Pre treatment forrPonds„144P�s143Pgr152Pj;&>444P,,, a> B C D E F TSS Removal Starting TSS Amount Remaining BMP' Rate' Load* Removed C*D Load D-E d Deep Sump and Hooded a ' Catch Basiri, w 0.25 1.00 0.25 0.75 r . All Ad Sediment Forebay $ __' 0.25 Q Q 0.75 0.19 0.56 d �� <> ggm a W. 3 a/ Ow3t" �h 0.00 0.56 0.00 0.56 N�/� rybxaR��9+ V� Sit 0.00•`1° �,& may, . ~ r 0.00 0.56 0.00 0.56 co 1 z: : sj7�art t . nt.,� ,, , 0.00 0.56 0.00 0.56 Separate Form Needs to be Completed for Each Total TSS Removal = 44^i, Outlet or BMP Train SALE-0028 z�,�,F,h i y".'1 `,F Project \ � x � > s' Prepared d B � Y p y PMs �'�`",� Equals remaining load from previous BMP (E) Date: which enters the BMP Non-automated TSS Calculation Sheet must be used if Proprietary BMP Proposed 1.From MassDEP Storrnwater Handbook Vol. 1 Mass. Dept. of Environmental Protection v INSTRUCTIONS: version 1,Automated:Mar.4, 2008 1. In BMP Column, click on Blue Cell to Activate Drop Down Menu 2. Select BMP from Drop Down Menu 3. After BMP is selected, TSS Removal and other Columns are automatically completed. . Location Detention5p6slnt 142P<`143P1n152P<`8 144P` i� y B C D E F TSS Removal Starting TSS Amount Remaining BMP', Rate' Load" Removed (C*D) Load D-E �'4dDeepSpadHQKr � 0.25 1.00 0.25 0.75 Dt'TE�1't1on1 41aaa.t � OO � yC *+ t ) 0.80 0.75 0.60 0.15 Cz t x �ry,'�, .�,y,.;�,k.s���`', 0.00 0.15 0.00 0.15 N iJ ,rye"�'z3 xEromY:� £q qv��� 3 r Fs iz i 5 33 , 3 0.00 0.15 0.000.15 Oro V fj � 0.00 0.15 0.00 0.15 L ....................jr Separate Form Needs to be Completed for Each Total TSS Removal = 85% Outlet or BMP Train Project O1Jw € a � ' Q�" Prepared B PMB A p yw,i„ ,zw� ..., Equals remaining load from previous BMP (E) Date 28:1uIG115ks" which enters the BMP Non-automated TSS Calculation Sheet 94y1J_ must be used if Proprietary BMP Proposed 1. From MassDEP Stonnwater Handbook Vol. 1 Mass. Dept.of Environmental Protection � �■ s s� � alp al � �r � � � � � �: � � � � INSTRUCTIONS: Version 1,Automated.,Mer. 4, 2008 1. In BMP Column, click on Blue Cell to'Activate Drop Down Menu 2. Select BMP from Drop Down Menu 3. After BMP is selected, TSS Removal and other Columns are automatically completed. Location Treatment Chaln t Pond-78P 330 XL Units) ,; B C D E F TSS Removal Starting TSS Amount Remaining. BMP1 Rate' Load* Removed C*D Load D-E O Deep-. pl,and Hooded; t/ C±atch:,y,Ba�sln 0.25 1.00 0.25 0.75 O OtG t Spar�ato 0.25 0.75 0.19 0.56 4b[ x . °` _ 0.00 0.56 0.00 0.56 N tQyf3"a #ems £ aiz ; 0.00 0.56 0.00 0.56 •-.max rR. i IF via '' r�'td ;ir,�+�•>.:� 0.00 0-56. 0.00 0.56 Separate Form Needs to be Completed for Each Total TSS Removal = 4400 Outlet or BMP Train SALE-0028' u'3C»�+r-. r aT. Project - Prepared By PMB =? ,;, r } 'Equals remaining load from previous BMP (E) Date 31,`Atig 151 3 '3kr which enters the BMP Non-automated TSS Calculation Sheet - must be used if Proprietary BMP Proposed 1. From MassDEP Stonnwater Handbook Vol..1 Mass. Dept. of Environmental Protection INSTRUCTIONS: version 1,Automated:Mar. e,2008 1. In BMP Column, click on Blue Cell to Activate Drop Down Menu 2. Select BMP from Drop Down Menu 3. After BMP is selected, TSS Removal and other Columns are automatically completed. WW Location TreatmentChaln,;=Pond 78P�(Cultec:330kXff Units)a, . . B C D E F TSS Removal Starting TSS Amount Remaining BMP1 Rate' Load* Removed C*D Load D-E ge 0) Dee0Sum0andrHood&& Q w �' CatchBastn4 0.25 1.00 0.25 0.75 "SSS .. Y il,3Subsurfacednfiltrattony`• 0 Q � Tyf Sttvcture � z ;f 0.80 0.75 0.60 0.15 I Q � ; y" 0.00 0.15 0.00 0.15 U) 0400 0.00 0.15 0.00 0.15 0.00 0.15 0.00 0.15 Separate Form Needs to be Completed for Each Total TSS Removal = 86% Outlet or BMP Train Project Prepared By PMBy. 'tr� *Equals remaining load from previous BMP (E) Date: which enters the BMP Non-automated TSS Calculation Sheet - must be used if Proprietary BMP Proposed 1.From MassDEP Stonnwater Handbook Vol. 1 Mess. 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'SER- !'` rER���!�.:i���■■■■■■ .■■■■■■■■.�1l.�c--_ CEJ[?-�!'.'��*n■■■■■■■■■■■■■■■■■■I .■■I■■■■■■■■■■■■■■■...�..............E .■■ ■■■■■■■■■■■■■■■■■�■ ..............■ �■■■■■■■■■■■■■■■■■■■ ■. ■■■■■■■■■■■■ ..■................■C■■■■■■■■■■■■■■■■ ■■e■■■■■n■■■■u■■■■■■■■n■■■n■ • : 1 :: • ate - • �■■■■■■■n■m■■mnne■■■r■rn■■■mr ►iTS !!:t�■i�R7 ltri'�\;��•'?!?'-!�` �s[�■■■■■■■■■ ■■■i■■■■■■■■■■■■■■NON ME M ME CIO z TPTJ CON I SRI �ii■ei�i■■■■■■■■■■■r ■■■■■■■■■■■■■■■■■ e■■ ■■■■■M■■■■■■■■■ ■■�T!!'■ ■I!.^�l�!!['!�f■Fob - MMIT-MIC m—m-na 4�■■■■■■■ ■■■rir■a■■■■■■■�■�■■�i■■■■■■■■■■■■ONE ■ ■■■■■■■■■r!m!JCS I■■■■■■■■■■ imp REMIN FXT'-�wCIC,�E'! FRff'Vii?Nln■E�G�'G� !■1�c9�-i1�!■■■■■■ is■■iiiii� iii■ iiiiiiiiiiii■iiiii ■■■Ii�1!!��3 !16ii �!ii1hVM7�'=7Ly K!■■■■■■■■■. ■!L!■%��'!G�!'�L!�ClL�JlC°a��'• En11C�lQ R ■■■■■■■'. !_?,9�,rM!*■■e■■■t!!!'*7 1�e _RMMf �AMM■■■■■■ff lfi3'�ll�'�!■■l�lL3i���!l���C''!'.z�C�1'�� �t�►L��■ 1 I xo 100 Year Storm Event / 1 HY-8 Analysis Results 1 Culvert Summary Table - 18" HDPE Culvert Crossing: Detention Pond Leine In _ 1 otal ulvert eadwa Inlet utlet low omial dtical Outlet aihvate ueet aitwate ischar ischar ter Control ontrol Type epth epth Depth Depth elocity e(cfs) a(cfs) levatio epth(ft) epth(ft) (ft) ft) (ft) (ft) fUs) Velocity fl ft1s 1 .72 .72 135.51 1.25 .51 Ff .75 .83 1.50 135.20 .67 .00 .90 .90 135.54 1.28 .54 FFf .76 .85 1.50 135.20 .78 .00 .09 .09 135.56 1.31 .56 FFf .78 .86 1.50 135.20 .88 .00 .27 .27 135.59 1.34 .59 FFf .80 .88 1.50 135.20 .98 .00 1 .46 .46 135.62 1.37 .62 Ff .81 .90 .50 35.20 .09 .00 .64 .64 135.65' .40 .65 Ff .83 .91 1.50 135.20 .19 .00 .82 .82 135.68 1.43 .68 Ff .85 .93 1.50 135.20 .30 .00 '1 .01 . .01 135.71 1.46 .71 Ff .87 .94 1.50 135.20 .40 .00 .19 .19 135.74 1.49 .74 Ff .88 .96 1.50 135.20 .50 .00 .38 .38 135.77 1.53 .77 Ff .90 .97 1.50 135.20 .61 .00 .56 .56 135.81 1.56 .81 jFFf 10.92 0.99 11.50 1135.20 13.71 1D.00 1 V-.1" aF G'(6 : 1310 .tL ST4 tk65 1 Ko So".+4P<L& 1--Dc 1 1 . 1 1 1 1 1 1 1 1 100 Year Storm Event 1 HY-8 Analysis Results 1 Culvert Summary Table - 15" HDPE Culvert Crossing: Detention Pond 2 Pipe In otal ulvert eadwa Met utiei low orrnal rilical utlel ailwate utlet ailwate 1 ischar ischar ter ontrol ontrol Type epth epth epth Depth eloctly e(ds) a(ds) levatio epth(ft) epth(ft) ft) (ft) ft) (ft) ft/s) elocity ft ft!s 1 .29 .29 136.09 .28 .0' 1-S2n .13 .21 .13 130.19 .35 .00 81 .81 136.28 .47 .0' 1-S2n 23 .35 .23 130.19 .37 .00 1.33 1.33 136.43 .62 .0' 1-S2n .28 .45 28 130.19 .29 .00 1.84 1.84 136.57 .76 .0' 1-S2n .34 .54 .34 130.19 .81 .00 1 .36 .36 136.70 .89 .0' I-q2n S2n .38 .61 .38 30.19 .48 .00 .88 .88 136.81 1.00 .0' S2n .43 .68 .43 130.19 .76 .00 .40 .40 136.93 1.12 .0' S2n .47 .74 .47 130.19 .12 .00 1 .92 .92 137.04 1.23 .0' S2n .50 .80 .50 130.19 .49 .00 .43 .43 137.16 1.35 .0' S2n .54 .85 .54 130.19 .71 .00 .95 .95 137.28 1.47 .0' S2n .58 .90 .58 130.19 .95 .00 .47 .47 137.42 1.61 .0' .61 .94 .62 130.19 .OS .00 1 T- wM o DMio4 5r7A 110 rau�c.cr�+t-Es►►.IG , �t�tl ,�'1�P� Off. God 1 C041-00 Les 1 1 1 1 1 1 1 1 1 1 100 Year Storm Event HY-8 Analysis Results ' Culvert Summary Table - 12" HDPE Culvert Crossing: Detention Pond 3 Pipe In le ulvert eadwa Met utlet low ormal ritical utlet aihvate utlet ailwateischar er ontrol ontrol ype epth epth epth Depth elocity ra(cfs) levatio epth(ft) epth(ft) ft) ft) ft) ft) Ws) elocityft ft/s.13 145.12 .94 .0• 1-S2n .34 .62 .34 116.87 .97 .00.57 145.26 1.08 .0' S2n .36 .68 .38 116.87 .46 .00.02 145.42 1.24 .0' Stn .41 .74 .41 16.87 .93 .00.46 145.59 1.41 .0' Stn .45 .79 .45 116.87 .99 .00.90 145.80 .62 .0• S2n .48 .84 .49 16.87 10.28 .00 .34 146.03 .85 .0' S2n .51 .87 .52 116.87 10.49 .00 .79 146.29 .11 .0' -S2n .54 .91 .56 116.87 10.69 .00 .23 146.58 .40 .20 -S2n .57. .93 .59 116.87 10.89 .00 .67 146:90 .72 .59 -S2n .60 .94 .62 16.87 11.10 .00 .12 147.24• .06 1.00 S2n .63 .93 .65 116.87 11.27 .00 .56 147.62 .44 1.46 S2n 1.67 1.96 1.69 116.87 11.40 .00 tM of Gbs _ No skxc wp-t.t 06 , 12" l-tDfIr 0L 1.100 Year Storm Event HY-8 Analysis Results ' Culvert Summary Table - 18" HDPE Culvert Crossing: Detention Pond 4 Pine In ' otal ulverl eadwa nlei Foutiet Flow slormaill ritical utlel ailwate Outlet aihvale ischar ischar ter ontrol ontrol Type epth epth epth Depth Velocity r e(cfs) a(ds) levalio epth(ft) epth(ft) ft) ft) ft) (ft) ft/s) elocity, ft fUs .57 .57 141.77 .77 .0• 1-S2n .25 .60 .25 120.46 12.80 .00 .19 .19 141.90 .90 .0• 1-S2n .29 .68 .29 120.46 13.74 .00 81 .81 142.01 1.01 .0' 1-S2n 31 .75 .33 120.46 13.03 .00 .43 .43 142.12 1.12 .0• -S2n .33 .81 .33 120.46 15.06 .00 ' .05 .05 142.22 1.22 .0' 1-S2n .36 .86 .36 120.46 15.60 .00 .66 .66 142.32 1.32 .0• 1-S2n .38 .91 .40 120.46 4.88 .00 .. .28 .28 142.42 1.42 .0• 1-S2n .40 .96 .40 120.46 16.43 .00 .90 .90 142.53 1.53 .0• -82n .42 1.01 .42 120.46 16.97 .00 .52 .52 142.64 1.64 .0' -S2n .44 1.06 .44 120.46 17.54 .00 .14 .14 142.76 1.76 .0• S2n .46 11.10 P.46. 120.46 18.04 .00 .76 .76 142.89 1.89 .0• S2n 10.48 11.14 10.48 V20.46 18.15 1.00 RaM O(- OM61 5T.Or l®+(010 = 19.4- 1 IJb SvI.C.{dh'f.�e1►•J(� � %ell N'p04L OUL GZg �, Gor�1'fzot.� t Z9/2o 100 Year Storm Event HY-8 Analysis Results ' Culvert Summary Table - 12" HDPE(Copy) Culvert Crossing: Cultec System Pipe In J71 ulvert eadwa nlet udet low ormal ritical ullet ailwate utlet aihxate ischar er ontrol ontrol ype epth epth epth Depth elocity a(cfs) IevaBo epth(ft) epth(ft) (ft) (ft) ft) ft) fus) elocity ft ft/s.04 127.91 .08 .66 Ff .04 .04 1.00 127.91 .OS .00 OS 127.91 .10 .66 Ff O6 OS 1.00 127.91 O6 .00 .06 127.91 .15 .66 FFf .07 .10 1.00 27.91 .08 .00 .OB 127.91 .19 .66 Ff .09 .11 1.00 127.91 .10 .00 .09 127.91 .24 .66 Ff .09 .12 1.00 127.91 .11 .0010 127.91 .32 .66 Ff .10 .13 1.00 127.91 .13 .00 .12 127.91 .48 .66 FFf .10 .14 .00 127.91 .15 .00 .14 127.91 .20 .66 FFf .11 .15 1.00 27.91 .17 .00 .15 127.91 .21 .66 FFf .12 .16 .00 127.91 .20 .00 .17 127.91 .23 .66 Ff 72 .16 1.00 127.91 .22 .00 .19 127.91 .24 .66 Ff .13 .17 1.00 127.91 .24 .00 1W �A h O F 'r/(1L Cib e CJ-,* Gtr O Wtr._ Prt.+r- PCS hJ ta!fA� '5 P, T vrLt J to Ico `t(t- `r'D R-M CAS. 2 Ger'tQa�-S 1 &°" �' .•m�-- +.r- .x�.—mss� ^'t" $ � .T/ �y t F '°N+�� € . ,. > Y..za s a ��`�S' sra w - +� �+n xxh •Y�?.�' bX+�`„sh�^��=L,� �-��„' �� . - aa T � 1 �r^ ti �h xt 3 2 � v4 r ��� ���"/•eFC ww � , K `' b �� r C z a s e . -C ° 4 s •5c r�,s�` 3'W'" `in x r _S k rk-A uhf d• c a -r" s fu. of Cs s > d '. SA4., D "i �^s sYkxyt„y Jy Y.' 1-1 6.22W � � ; % y 2 �^�`�, v y z k a �✓,� wF.riie i "F'�,' ax•2 "j•3`s�,�'� 102E .( C21 ��€! a �� � t V=ti yy t ra M *T€j � "` �•hfw�ir�"� °�`e sxR ka*$.y� � ry 4���*� x >� � ` a •s, Y � = ..np { ' g .u�� °� a-:�'� s� t• f'.,�Y;1 *�,, i sS' sv a r W� f `I 7 _'.4,�ra�•yyad� r: g xS a,,,,�r7r�.we...;s. s.�s.,� ,- uyya.,�¢¢'33dd�s 3�pp55�� ai s "° y w ,.r:, ,.d>;'4 ..>•o,u .dau` ��„ ,h Ye...,.�,as�v.�.�?�._�.zd�sw�.'xcx'�R• . Is c?-�,n�`?�„ r a a� .ra •aa Hydrologic Soil Group—Essex County,Massachusetts,Southern Part (The Woodlands-Clark Avenue,Salem MA). MAP LEGEND MAP INFORMATION Area of Interest(Aot) ■ C The soil surveys that comprise your AOI were mapped at 1:15,800. O Area of Interest(AOI) ■ CID Soils Warning:Soil Map may not be valid at this scale. D Soil Rating Polygons ■ Enlargement of maps beyond the scale of mapping can rouse ® A p Not rated or not available misunderstanding of the detail of mapping and accuracy of soil line placement.The maps do not show the small areas of contrasting ® AM Water Features soils that could have been shown at a more detailed scale. Streams and Canals Transportation Please rely on the bar scale on each map sheet for map BfD t-t-t Rens measurements. C N Interstate Highways Source of Map: Natural Resources Conservation Service ® CID Web Soil Survey URL: httpJ/websoilsuNey.nros.usda.gov ,y US Routes Coordinate System: Web Mercator(EPSG:3857) ® D Major Roads Maps from the Web Soil Survey are based on the Web Mercator Q Not rated or not avalleble Low Roads projection,which preserves direction and shape but distorts Soil Rating Linea distance and area.A projection that preserves area,such as the Background Albers equal-area conic projection,should be used H more accurate ~ A . Aerial Photography calculations of distance or.area are required. ^� AM This product Is generated from the USDA-NRCS certified data as of ,y g - the version date(s)listed below. .y BfD Soil Survey Area: Essex County,Massachusetts,Southern Part C Survey Area Data: Version 11,Sep 19,2014 N Soli map units are labeled(as space allows)for map scales 1:50,000 M C(D or larger. D Date(s)aerial Images were photographed: Aug 10,2014—Aug . 1 Not rated or not available 25,2014 Soil Rating Points The orthophoto or other base map on which the soil lines were ■ A compiled and digitized probably differs from the background Imagery displayed on these maps.As a result,some minor shifting ■ AID Imagery map unit boundaries may be evident. ■ B ■ BID Natural Resources Web Soil Survey 9/18/2015 Conservation Service National Cooperative Soil Survey Page 2 of 4 ' Hydrologic Soil Group—Essex County,Massachusetts,Southern Pan The Woodlands-Clark Avenue, Salem MA Hydrologic Soil Group ' Hydrologic Soil Group—Summary by Map Unit-Essex County,Massachusetts,Southern Part(MA606) --Map unit symbol Map unit name Rating Acres in AOI Percent of AOI - 53A Freetown muck,ponded, AID 0.5 1.1% 0 to 1 percent slopes MLRA 144A 73A Whitman loam,0 to 3 D 5.0 10.6% percent slopes, extremely stony 102C Chatfield-Hollis-Rock B 5.7 12.1% outcrop complex,3 to 15 percent slopes 102E Chatfield-Hollis-Rock B 36.1 76.3% ' outcrop complex,15 to 35 percent slopes Totals for Area of Interest 47.3 100.0% W� QR tori OOKOAaD CJ+u o"nows 1 ' tSM Natural Resources Web Soil Survey 9/182015 iQ Conservation Service National Cooperative Soil Survey Page 3 of 4 ' Hydrologic Soil Group--Essex County,Massachusetts,Southern Part The Woodlands-Clark Avenue, Salem MA ' Description Hydrologic soil groups are based on estimates of runoff potential. Soils are assigned to one of four groups according to the rate of water infiltration when the soils are not protected by vegetation,are thoroughly wet,and receive precipitation ' from long-duration stones. The soils in the United States are assigned to four groups(A, B, C, and D)and three dual classes(AID, BID,and CID).The groups are defined as follows: ' Group A. Soils having a high infiltration rate(low runoff potential)when thoroughly wet.These consist mainly of deep,well drained to excessively drained sands or gravelly sands.These soils have a high rate of water transmission. Group B. Soils having a moderate infiltration rate when thoroughly wet.These consist chiefly of moderately deep or deep,moderately well drained or well drained ' soils that have moderately fine texture to moderately coarse texture.These soils have a moderate rate of water transmission. Group C. Soils having a slow infiltration rate when thoroughly wet.These consist ' ,chiefly of soils having a layer that impedes the downward movement of water or soils of moderately fine texture or fine texture.These soils have a slow rate of water transmission. Group D. Soils having a very slow infiltration rate(high runoff potential)when thoroughly wet. These consist chiefly of Gays that have a high shrink-swell potential, soils that have a high water table,soils that have a claypan or clay layer ' at or near the surface, and soils that are shallow over nearly impervious material. These soils have a very slow rate of water transmission. If a soil is assigned to a dual hydrologic group(AID, BID, or CID),the first letter is for drained areas and the second is for undrained areas.Only the soils that in their natural condition are in group D are assigned to dual classes. Rating Options Aggregation Method: Dominant Condition ' Component Percent Cutoff. None Specified Tie-break Rule: Higher ' Natural Resources Web Soil Survey 9I18I2015 Conservation Service National Cooperative Soil Survey Page 4 of 4 Operation & Maintenance Plan .Proposed Cluster Residential Subdivision "The Woodlands' Clarke Avenue, Salem MA August 14, 2015 ' Revised: August 31, 2015 Structural Best Management Practices (BMPs) require periodic maintenance to insure proper ' function and efficiency in pollutant removal from stormwater discharges that would otherwise discharge from the proposed impervious areas untreated. Maintenance schedules fourid below are, as recommended in the manufacturer's specifications. ' The following BMPs shall be utilized for project for pollutant removal from stormwater discharge as well providing additional groundwater recharge on site by directing the proposed runoff to four (4) ' surface detention ponds and one (1) subsurface infiltration area: • Deep Sump Catch Basins with hoods ' • 1,500 Gallon Sediment&Oil Separator . • Street Sweeping • Cultec Recharger 330XL Chambers • Detention Ponds 1,2,3&4 Deep Sump Catch Basins with hoods&1,500 Gallon Sediment&Oil Separator: • Inspect the units at least four times per year with special consideration given to the end of foliage and snow removal seasons. • Inspect the condition of the catch basin hoods installed in the outlet pipes from the catch ' basins. If damaged, remove and replace with a new unit. • Sediments must also be removed four times per year or whenever the depth of deposits is greater than or equal to one half the depth from the bottom of the invert of the lowest pipe in the unit. Clamshell buckets and/or vacuum trucks are typically used to remove sediment in Massachusetts. • Catch basin cleanings may be taken to a landfill or other facility permitted by MassDEP to accept solid waste,without any prior approval by MassDEP. However,some landfills require catch basin cleanings to be tested before they are accepted. For information on all of the MassDEP requirements pertaining to the disposal of catch basin cleanings go to ' www.Mass. og v/dep/recycle/laws/cafacts.doc Street Sweeping • Street sweeping should be conducted as needed or once minimum per year in the spring ' ' (Mardi or April). ' Operation & Maintenance Plan Proposed Cluster Residential Subdivision Salem, MA August 14, 2015 Revised: August 31, 2015 ' Cultec Recharger 330XL Chambers: ' . Access to the chambers is through the inspection ports to be located at either end of the row of chambers where shown on the site plan. • From the surface, through these inspection ports,the sediment may be measured. A stadia rod may be used to measure the depth of sediment,if any. ' • Once the depth of sediment is in excess of three (3") inches, the affected Cultec Chambers shall be excavated and the six (6) inch stone bed beneath them is removed and replaced with clean stone. ' • Should standing water be present in bottom of system during a routine inspection or more than twenty-four (24)hours after the end of a rainfall event, it may be as a result of the stone t bed layer being clogged with fine particles. The amount of elapsed time required for the water to infiltrate completely should be recorded. If after seventy-two (72) hours from the end of a rainfall event there is still standing water in the bottom of the chambers,excavate ' the system and replace the stone bed layer with clean stone as mentioned above. • We recommend the following schedule for system maintenance ' Monthly in fust year of service: -Check inlets and outlets for clogging and remove any debris as necessary -Check for settlement in areas over and surrounding the system Spring and fall in the second year service: ' -Check inlets and outlets for clogging and remove any debris as necessary -Check for settlement in areas over and surrounding the system t One year after commissioning and everyyear folloj rnM. -Check inlets and outlets for clogging and remove any debris as necessary -Inspect the interior of the chambers via inspection ports and measure sediment or t depth of standing water -Check for settlement in areas over and surrounding the system -Confirm that no unauthorized modifications have been performed to the site I ' • It should be noted that most failures occur in subsurface systems such as these due to inadequate pre-treatment which leads to clogging. However,with the installation of deep- sump catch basins with hoods and the Sediment&Oil Separator we do not expect there to be any adverse impacts to the system due to debris accumulation. 1 2 1 Operation &Maintenance Plan Proposed Cluster Residential Subdivision Salem, MA August 14, 2015 Revised: August 31, 2015 ' . Detention Basins: ' • Detention Basins require small-scale maintenance at regular intervals to evaluate its health and composition. • Carefully observe over time. In the first three years after construction, inspect twice a year during both the growing and non-growing seasons. ' • During these inspections,record and map the following information: Presence of standing water ' Vegetative condition (For sides and bottom use a mixture of grass seeds capable of withstanding periodic inundation under water,and,drought tolerant during summer. ' Stability of the sideslopes and berms, Survival rate of plantings,if any(dead plantings must be replanted) 1 3 1 1 Erosion & Sediment Control Plan The Woodlands (Clarke Avenu) Salem, MA August 31, 2015 In order to limit the amount of erosion and sedimentation that takes place during and after construction,it is important to implement a management plan,which will protect and limit the amount of land area that is ' devoid of vegetation at any given time. Prior to Construction-Prior to start of construction activities, the owner,builder,and site contractor shall clearly identify areas that may be affected by the proposed clearing and earth moving activities by reviewing the approved grading plan as part of an initial site visit. During the site visit, the limit of work line shall be reviewed to confirm the type of erosion control measure to be used to protect downstream wetland resources ' and abutting property. Limits of tree clearing shall be verified during the initial site visit with emphasis on identifying"save areas" for existing trees and vegetation where practicable. Erosion and Sediment Control Device Siltfence and haybales are proposed as the primary erosion control device for this project(see construction edetail provided on the subdivision plan set). It is important for the owner,builder,and/or site contractor to have access to a supply of haybales should the need arise for additional erosion and sediment control ' measures. Haybales can be used along a slope and/or together with siltfence to protect against concentrated stormwater runoff over exposed surfaces (see attached construction detail for haybale installation). The erosion and sediment control devices shall be inspected every 7 days or within 24-hours of a 1/2-inch(or greater) rainfall event to ensure that they are operating properly. If sediment levels begin to build up on the erosion control devices,it may be necessary to remove the accumulated sediment to ensure that the erosion control devices continue to operate as designed. Sediment shall be removed if it builds up more than 12-inches above the ground surface at the erosion control device. Earth-moving Activities After trees and other vegetation are cleared,earth-moving (or grading) activities can begin. The approved grading plan shall be used to help guide the site contractor during regrading activities. Oftentimes it is helpful to have a land surveyor establish benchmark elevations and/or lines of grade to aid the site contractor during regrading activities. This is the time during which the site is most vulnerable to erosion. Therefore,it is important for the site contractor to finalize grading activities as soon as practicable following land clearing. Areas than remain exposed longer than 30 working days in an interim condition shall be stabilized in a temporary fashion. Once final grades have been established,permanent vegetation can be established. ' Temporary Seeding During construction it may be necessary to temporarily stabilize areas that will not be brought to final grade for a period longer than 30 working days. Temporary seeding is accomplished using fast-growing grass seed species such as ryegrass. Seeding shall be performed in accordance with the guidelines set forth in the Temporary Seeding Guidance,which is an excerpt from a publication entitled, "Massachusetts Erosion and ' .Sediment Control Guidelines for Urban and Suburban Areas,May 2003,prepared by Franklin,Hampden, and Hampshire Conservation Districts" Erosion & Sediment Control The Woodlands(Clarke Avenu) ' Salem, MA August 31, 2015 ' Permanent Seeding&Plantings Once final grades have been established and the weather permits, every effort shall be made to establish ' permanent vegetation on disturbed and exposed areas. In addition to grass seed, tree and shrub plantings shall be an integral part of the permanent stabilization plan. Care shall be taken by the owner,builder,and/or site contractor to select trees,shrubs,and seed mixes that are best suited to the soil conditions on the site. Soil moisture, depth to seasonal groundwater,and exposure to sunlight shall be carefully considered when selecting species. In recent years, the emphasis on using plant species native to Massachusetts has grown. Information on the use of non-native and native species can be found on the web and in many local nursery catalogs. Permanent seeding shall be performed in accordance with the guidelines set forth in the Permanent Seeding ' Guidance,which is an excerpt from a publication entitled,"Massachusetts Erosion and Sediment Control Guidelines for Urban and Suburban Areas,May 2003,prepared by Franklin, Hampden, and Hampshire Conservation Districts." i 2 1 i 1 Attachment A 1 "Temporary Seeding Guidance Document". 1 1 1 1 1 1 1 i 1 1 1 142 Erosion and Sediment Control Practices Maintenance ' Inspect seeded areas for failure and make necessary repairs and reseed immediately. Conduct or follow-up survey after one year and replace failed plants where necessary. If vegetative cover is inadequate to prevent rill erosion, overseed and fertilize in accordance with soil test results. If a stand has less than 40% cover, reevaluate choice of plant materials and quantities of lime and fertilizer. Reestablish the stand following seedbed preparation and seeding recommendations, omitting lime and fertilizer in the absence of soil test results. If the season prevents resowing, ' mulch or jute netting is an effective temporary cover. Seeded areas should be fertilized during the second growing season. Lime and fertilize thereafter at periodic intervals, as needed. References' ' North Carolina Department of Environment, Health, and Natural Resources, .Erosion and Sediment Control Field Manua[, Raleigh, NC, February 1991. Personal communication, Richard J. DeVergilio, USDA, Natural Resources Conservation Service,Amherst, MA. U.S. Environmental Protection Agency,Storm Water Management For Construction Activities, EPA-832-R-92-005,Washington, DC, September, 1992. Washington State Department of Ecology,Stormuater Management Manual for the Puget Sound Basin,Olympia,WA, February, 1992. Seeding; Temoras Planting rapid-growing annual grasses, small grains,or legumes to provide initial, temporary cover for erosion control on disturbed areas. Purpose ' To temporarily stabilize areas that will not be brought to final grade for a period of more than 30 working days. To stabilize disturbed areas before final grading or in a season not suitable ' for permanentseeding. Temporary seeding controls runoff and erosion until permanent vegetation or other erosion control measures can be established. Root systems hold down the soils so that they are less apt to be carried offsite by storm water runoff or wind. Temporary seeding also reduces the problems associated with mud and dust from bare soil surfaces during construction. Erosion and Sediment Control Guidelines Erosion and Sediment Control Practices 143 Where Practice Applies On any cleared, unvegetated, or sparsely vegetated soil surface where vegetative cover is needed for less than one year. Applications of this practice include diversions,dams, temporary sediment basins, temporary road banks,and topsoil stockpiles. Where permanent structures are to be installed or extensive re- grading of the area will occur prior to the establishment of permanent vegetation. Areas which will not be subjected to heavy wear by construction traffic. Areas sloping up to 10% for 100 feet or less,where temporary seeding is the only practice used. ' Advantages This is a relatively inexpensive form of erosion control but should only be used on sites awaiting permanent planting or grading. Those ' sites should have permanent measures used. Vegetation will not only prevent erosion from occurring, but will also trap sediment in runoff from other parts of the site. Temporary seeding offers fairly rapid protection to exposed areas. Disadvantages/Problems ' Temporary seeding is only viable when there is a sufficient window in time for plants to grow and establish cover. It depends heavily on the season and rainfall rate for success. If sown on subsoil, growth will be poor unless heavily fertilized and limed. Because overfertilization can cause pollution of stormwater runoff,other practices such as mulching alone may be more appropriate.The potential for over-fertilization is an even worse problem in or near aquatic systems. Once seeded,areas should not be travelled over. Irrigation may be needed for successful growth. Regular irrigation is not encouraged because of the expense and the potential for erosion in areas that are not regularly inspected. Planning Considerations Temporary seedings provide protective cover for less than one year.Areas must be reseeded annual or planted with perennial vegetation. Temporary seeding is used to protect earthen sediment control practices and to stabilize denuded areas that will not be brought into final grade for several weeks or months. Temporary seeding can provide a nurse crop for permanent vegetation, provide residue for soil protection and seedbed preparation, and help prevent dust production ' during construction. Erosion and Sediment Control Guidelines 1 144 Erosion and Sediment Control Practices Use low-maintenance native species wherever possible. ' Planting should be timed to minimize the need for irrigation. Sheet erosion, caused by the impact of rain on bare soil, is the source of most fine particles in sediment.To reduce this sediment load ' in runoff, the soil surface itself should be protected.The most efficient and economical means of controlling sheet and rill erosion is to establish vegetative cover. Annual plants which sprout rapidly and survive for only 1 one growing season are suitable for establishing temporary vegetative cover.Temporary seeding is effective when combined with construction phasing so bare areas of the site are minimized at all times. Temporary seeding may prevent costly maintenance operations on other erosion control systems. For example, sediment basin clean-outs will be reduced if the drainage area of the basin is seeded where grading and construction are not taking place. Perimeter dikes will be more effective if not choked with sediment. Proper seedbed preparation and the use of quality seed are important in this practice just as in permanent seeding. Failure to carefully follow sound agronomic recommendations will often result in an inadequate stand of vegetation that provides little or no erosion control. Soil that has been compacted by heavy traffic or machinery may need to be loosened. Successful growth usually requires that the soil be tilled before the seed is applied.Topsoiling is not necessary for temporary seeding; however, it may improve the chances of establishing temporary vegetation in an area. Planting Procedures Time of Planting Planting should preferably be done between April 1 and June 30, and September 1 through September 30. If planting is done in the months of July and August, irrigation may be required. If planting is done between October 1 and March 31, mulching should be applied immediately after planting. If seeding is done during the summer months, irrigation of some sort will probably be necessary. Site Preparation ' Before seeding, install needed surface runoff control measures such as gradient terraces, interceptor dike/swales,level spreaders,and sediment basins. Seedbed Preparation The seedbed should be firm with a fairly fine surface. Perform all cultural operations across or at right angles to the slope. See Topsoiling and Surface Roughening for more information on seedbed preparation.A minimum of 2 to 4 inches of tilled topsoil is required. Erosion and Sediment Control Guidelines ' Erosion and Sediment Control Practices 145 Liming and Fertilization ' Apply uniformly 2 tons of ground limestone per acre(100 lbs. per 1,000 Sq. Ft) or according to soil test. Apply uniformly 10-10-10 analysis fertilizer at the rate of 400 lbs. per acre(14 lbs. per 1,000 Sq. Ft)or as indicated by soil test. Forty percent of the nitrogen should be in organic form. Work in lime and fertilizer to a depth of 4 inches using any suitable equipment r twUSW ft``L t s�yk' 'ZT.:Fn;4Y3„ xc'' i T,• H>* ;:x r'; • x Seedmgs for Temporary Covent, x a M e"dmg Rat-16s/s9.ft q :r' rW-Recomme"ndedr4 =+nr a Tv334 r+. ` x � ee & •i' &q, i Acre „fit�Seedm abates .� {`,r L2 "i" g er i � /•na`3. J vl�. '1 �l J„an f pp Rryi�a'�• tr'�"sa ��,�� �f !Annual Ryegrass 1 40 sApnl 1�toiJuneMN .l r � y� "rtnSR$ ak ' tiglStSept°1 FoxtailMillet. U7 ^�� �30y� �May`;1toJune30 �' �"'�'. � . -•ate���� . �, � �s�,. ,�, , ��: A A111' Sept -. ` t W nter,Rye", t �Hydro-seedmg apphcaUons,wtth3'appropriate seed-mulch fertihzer��. muttureszmayalso�be,used�4���2�{ ,', ���,�` �5� Seeding Select adapted species from the accompanying table. Apply seed uniformly according to the rate indicated in the table by broadcasting, drilling or hydraulic application. Cover seeds with suitable equipment as follows: ' .Rye grass % inch aMillet �I to 3/4 inch ' Oats 1 to 1-1/2 inches o-Winter rye 1 to 1-1/2 inches. Mulch Use an effective mulch, such as clean grain straw; tacked and/or tied down with netting to protect seedbed and encourage plant growth. Common Trouble Points Lime and fertilizer not incorporated to at least 4 inches ' May be lost to runoff or remain concentrated near the surface where they may inhibit germination. Mulch rate inadequate or straw mulch not tacked down ' Results in poor germination or failure, and erosion damage. Repair damaged areas, reseed and mulch. Erosion and Sediment Control Guidelines ' 146 Erosion and Sediment Control Practices Annual ryegrass used for temporary seeding ' Ryegrass reseeds itself and makes it difficult to establish a good cover of permanent vegetation. Seed not broadcast evenly or rate too low ' Results in patchy growth and erosion. Maintenance ' Inspect within 6 weeks of planting to see if stands are adequate. Check for damage after heavy rains. Stands should be uniform and dense. Fertilize, reseed, and mulch damaged and sparse areas immediately. Tack or tie down mulch as necessary. Seeds should be supplied with adequate moisture. Furnish water as needed, especially in abnormally hot or dry weather or on adverse sites. ' Water application rates should be controlled to prevent runoff. References ` 1 Massachusetts Department of Environmental Protection, Office of Watershed Management, Nonpoint Source Program, Massachusetts Nonooint Source Management Manual, Boston, Massachusetts,June, 1993. North Carolina Department of Environment, Health, and Natural Resources,. ' Erosion and Sediment Control Field Manual, Raleigh, NC, February 1991. U.S. Environmental Protection Agency,Storm Water Management For Construction Activities, EPA-832-11-92-005,Washington, DC, September, 1992. Washington State Department of Ecology,Stormwater Management Manual jfor the Puget Sound Basin,Olympia,WA, February, 1992. I ' Silt Curtain A temporary sediment barrier installed parallel to the bank of a stream or lake. Used to contain the sediment produced by construction ' operations on the bank of a stream or lake and allow for its removal. Where Practice Applies ' The silt curtain is used along the banks of streams or lakes where sediment could pollute or degrade the stream or lake. Erosion and Sediment Control Guidelines ' Attachment B "Permanent Seeding Guidance Document" ' 132 Erosion and Sediment Control Practices Maintenance The effective life of a sediment trap depends upon adequate maintenance. The trap should be readily accessible for periodic maintenance and sediment removal. ' Set a stake at one-half the design depth. This will be the"cleanout level." Remove sediment when it has accumulated to one-half the design depth. Inspect sediment traps after each significant rainfall event. Repair any erosion and piping holes immediately. Clean or replace spillway gravel facing if clogged. Promptly replace any displaced riprap, being careful that no stones in the spillway are above design grade. Inspect vegetation; reseed and remulch if necessary. Check spillway depth periodically to ensure minimum of 1.5 it depth ' from lowest point of the settled embankment to highest point of spillway crest. Fill any low areas of the embankment to maintain design elevation. After all sediment-producing areas have been stabilized; inspected, ' and approved, remove the structure and all unstable sediment. Smooth site to blend with adjoining areas and stabilize in accordance with vegetation plan. ' References ' Minnick, E. L., and H. T. Marshall,Stormwater Management and Erosion Control for Urban and Developing Areas in New Hampshire, Rockingham County Conservation District,August 1992. ' North Carolina Department of Environment, Health, and Natural Resources, Erosion and Sediment Control Field Manual, Raleigh, NC, February 1991. ' U.S. Environmental Protection Agency,Storm Water Management For Construction Activities, EPA-832-R-92-005,Washington, DC, September, 1992. ' Washington State Department of Ecology,Stormwater Management Manual for the Puget Sound Basin, Olympia,WA, February, 1992. Seeding; Permanent � . ' The establishment of perennial vegetative cover on disturbed areas. Purpose ' Permanent seeding of grass and planting trees and shrubs provides stabilization to the soil by holding soil particles in place. ' Vegetation reduces sediments and runoff to downstream areas by slowing the velocity of runoff and permitting greater infiltration of the runoff. Erosion and Sediment Control Guidelines ' Erosion and Sediment Control Practices 133 Vegetation also filters sediments, helps the soil absorb water, ' improves wildlife habitats, and enhances the aesthetics of a site. Where Practice Applies ' a Permanent seeding and planting is appropriate for any graded or cleared area where long-lived plant cover is needed to stabilize the soil. o. Areas which will not be brought to final grade for a year or more. a Some areas where permanent seeding is especially important are filter strips, buffer areas,vegetated swales, steep slopes,and stream banks. a This practice is effective on areas where soils are unstable because of their texture or structure, high water table,winds, or steep slope. Advantages ' Advantages of seeding over other means of establishing plants include the small initial establishment cost, the wide variety of grasses and legumes available, low labor requirement,and ease of establishment ' in difficult areas. Seeding is usually the most economical way to stabilize large areas. Well established grass and ground covers can give an aesthetically pleasing, finished look to a development. Once established, the vegetation will serve to prevent erosion and retard the velocity of runoff. Disadvantages/Problems Disadvantages which must be dealt with are the potential for ' erosion during the establishment stage,a need to reseed areas that fail to establish, limited periods during the year suitable for seeding, and a need for water and appropriate climatic conditions during germination. Vegetation and mulch cannot prevent soil slippage and erosion if soil is not inherently stable. Coarse, high grasses that are not mowed can create a fire hazard in ' some locales. Very short mowed grass, however, provides less stability and sediment filtering capacity. Grass planted to the edge of a watercourse may encourage fertilizing and mowing near the water's edge and increase nutrient and pesticide contamination. Depends initially on climate and weather for success. May require regular irrigation to establish and maintain. ' Planning considerations Selection of the right plant materials for the site, good seedbed ' preparation, timing,and conscientious maintenance are important. Whenever possible, native species of plants should be used for landscaping. These plants are already adapted to the locale and Erosion and Sediment Control Guidelines ' 134 Erosion and Sediment Control Practices survivability should be higher than with "introduced"species. Native species are also less likely to require irrigation,which can be a large maintenance burden and is neither cost-effective nor ecologically sound. ' If non-native plant species are used, they should be tolerant of a large range of growing conditions, as low-maintenance as possible,and not invasive. ' Consider the microclimate within the development area. Low areas may be frost pockets and require hardier vegetation since cold air tends to sink and flow towards low spots.South-facing slopes may be more difficult to re-vegetate because they tend to be sunnier and drier. Divert as much surface water as possible from the area to be planted. Remove seepage water that would continue to have adverse effects on soil stability or the protecting vegetation.Subsurface drainage or other ' engineering practices may be needed. In this situation,a permit may be needed from the local Conservation Commission: check ahead of time to avoid construction delays. Provide protection from equipment, trampling and other destructive agents. Vegetation cannot be expected to supply an erosion control cover and prevent slippage on a soil that is not stable due to its texture, structure, water movement,or excessive slope. Seeding Grasses and Legumes Install needed surface runoff control measures such as gradient terraces, berms, dikes, level spreaders,waterways, and sediment basins prior to seeding or planting. Seedbed Preparation If infertile or coarse-textured subsoil will be exposed during land shaping, it is best to stockpile topsoil and respread it over the finished slope at ' a minimum 2-to 6-inch depth and roll it to provide a firm seedbed. If construction fill operations have left soil exposed with a loose, rough,or irregular surface, smooth with blade and roll. Loosen the soil to a depth of 35 inches with suitable agricultural or construction equipment. Areas not to receive top soil shall be treated to firm the seedbed after incorporation of the lime and fertilizer so that it is depressed no more ' than Si- 1 inch when stepped on with a shoe.Areas to receive topsoil shall not be firmed until after topsoiling and lime and fertilizer is applied and incorporated, at which time it shall be treated to firm the seedbed as ' described above. This can be done by rolling or cultipacking. Cool Season Grasses ' Cool Season Grasses grow rapidly in the cool weather of spring and fall, Erosion and Sediment Control Guidelines tErosion and Sediment Control Practices 135 and set seed in June and July. Cool season grasses become dormant ' when summer temperatures persist above 85 degrees and moisture is scarce. t Lime and Fertilizer Apply lime and fertilizer according to soil test and current Extension Service recommendations. In absence of a soil test, apply lime(a pH of ' 5.5-6.0 is desired) at a rate of 2.5 tons per acre and 10-20-20 analysis fertilizer at a rate of 500 pounds per acre(40 % of N to be in an organic or slow release form). Incorporate lime and fertilizer into the top 2-3 ' inches of soil. Seeding Dates ' Seeding operations should be performed within one of the following periods: a. April 1 -May 31, ' o. August I -September 10, November 1 -December 15 as a dormant seeding(seeding rates shall be increased by 50% for dormant seedings). 1 Seeding Methods Seeding should be performed by one of the following methods. Seed should be planted to a depth of y to �i inches. ' M Drill seedings, M Broadcast and rolled, cultipacked or tracked with a small track piece of construction equipment, Hydroseeding,with subsequent tracking. Mulch Mulch the seedings with straw applied at the rate of �i tons per acre. Anchor the mulch with erosion control netting or fabric on sloping areas. Warm Season Grasses Warm Season Grasses begin growth slowly in the spring, grow rapidly in the hot summer months and set seed in the fall. Many warm season ' grasses are sensitive to frost in the fall, and the top growth may die back. Growth begins from the plant base the following spring. Lime and Fertilizer ' Lime to attain a pH of at least 5.5.Apply a 0-10-10 analysis fertilizer at the rate of 600 lbs./acre. Incorporate both into the top 2-3 inches of soil. (30 lbs.of slow release nitrogen should be applied after emergence of grass in the late spring.) ' Erosion and Sediment Control Guidelines 1 ' 136 Erosion and Sediment Control Practices Seeding Dates ' Seeding operations should be performed as an early spring seeding(April 1-May 15) with the use of cold treated seed.A late fall early winter dormant seeding(November I'-December 15) can also be made, however the ' seeding rate will need to be increased by 50%. Seeding Methods ' Seeding should be performed by one of the following methods: a Drill seedings (de-awned or de-bearded seed should be used unless the drill is equipped with special features to accept awned seed). a Broadcast seeding with subsequent rolling, cultipacking or tracking the seeding with small track construction equipment.Tracking should be oriented up and down the slope. ' ,. Hydroseeding with subsequent tracking. If wood fiber mulch is used, it should be applied as a separate operation after seeding and tracking to assure good seed to soil contact. 1 Mulch Mulch the seedings with straw applied at the rate of Si tons per acre. ' Anchor the mulch with erosion control netting or fabric on sloping areas. Seed Mixtures for Permanent Cover Recommended mixtures for permanent seeding are provided on the following pages.Select plant species which are suited to the site conditions and planned use. Soil moisture conditions, often the major limiting site factor, are usually classified as follows: Dry-Sands and gravels to sandy loams. No effective moisture supply from seepage or a high water table. Moist-Well drained to moderately well drained sandy loams, loams,and finer;or coarser textured material with moderate influence on root zone from seepage or a high water table. Wet-All textures with a water table at or very near the soil surface, or with enduring seepage. ' When other factors strongly influence site conditions, the plants selected must also be tolerant of these conditions. t t Erosion and Sediment Control Guidelines ' Erosion and Sediment Control Practices 137 t ' Permanent Seeding Mixtures Seed, Pounds per: t Mix Site Seed Mixture Acre 1,000 sf Remarks l 1 Dry Little Bluestein 'Use Warm Season planting procedure. I or Broomsedge 10 0.25 'Roadsides Tumble Lovegrass' 1 0.10 .Sand and Gravel Stabilization ' Switchgrass 10 0.25 'Clover requires inoculation with nitrogen- fixing bacteria Bush Clover* 2 0.10 Red Top 1 0.10 'Rates for this mix are for PIS. ' 2 Dry Deertongue 15 0.35 ' Use Warm Season planting procedures. Broomsedge 10 0.25 'Acid sites/Mine spoil Bush Clover' 2 0.10 'Clover requires Inoculation with nitrogen- fixing bacteria. Red Top 1 0.10 'Rates for this mix are for PIS. 3 Dry BigBluestem 10 0.25 ' Use Warm Season planting procedures. Indian Grass 10 0.25 'Eastern Prairie appearance Switchgrass 10 0.25 'Sand and Gravel pits. Little Bluestein 10 0.25 'Golf Course Wild Areas Red Top or 1 0.10 .Sanitary Landfill Cover seeding Perennial Ryegrass 10 0.25 'Wildlife Areas 'OK to substitute Poverty Dropseed in place of Red Top/Ryegrass. 'Rates for this mix are for PIS. 4 Dry Flat Pea 25 0.60 - ' Use Cool Season planting procedures Red Top or 2 0.10 'Utility Rights-of-Ways(tends to suppress Perennial Ryegrass 15 0.35 woody growth) 5 Dry Little Bluestein, 5 0.10: .Use Warm Season planting procedures. Switchgrass 10 0.25 .Coastal sites Beach Pea' 20 0.45 ' Rates for Bluestein and Switchgrass are for Perennial Ryegrass 10 0.25 PIS. ' 6 Dry- Red Fescue 10 0.25 'Use Cool Season planting procedure. Moist Canada Bluegrass 10 0.25 ''Provides quick cover but is non-aggressive; ' Perennial Ryegrass 10 0.25 will tend to allow indigenous plant colonization. Red Top 1 0.10 ' General erosion control on variety of sites, including forest roads,skid trails and landings. 7 Moist- Switchgrass 10 0.25 •Use Warm Season planting procedure. Wet Virginia Wild Rye 5 0.10 'Coastal plain/flood plain Big Bluestein 15 0.35 'Rates for Bluestein and Switchgrass are for ' Red Top 1 0.10 . PIS. mma-j Erosion and Sediment Control Guidelines I 1 i . i138 Erosion and Sediment Control Practices r Permanent Seeding Mixtures ' ! Seed,Pounds per: I' Mix Site Seed Mixture Acre 1,000 sf Remarks i 8 Moist Creeping Bentgrass 5 0.10 * Use Cool Season planting procedures. Wet Fringed Bromegrass 5 0.10 ' Pond Banks Fowl Meadowgrass 5 0.10 *Waterways/ditch banks Bluejoint Reedgrass ior Rice Cutgrass 2 0.10 11t Perennial Ryegrass 10 0.25 9 Moist Red Fescue 5 0.10 *Salt Tolerant ' Wet Creeping Bentgrass 2 0.10 'Fescue and Bentgrass provide low growing appearance,while Switchgrass provides tall cover for wildlife. i Switchgrass 8 0.20 Perennial Ryegrass 10 0.25 10 Moist Red Fescue 5 0.10 *Use Cool Season planting procedure. i WetCreeping Bentgrass 5 0.10 *Trefoil requires inoculation with nitrogen 'fixing bacteria. Virginia Wild Rye 8 0.20 ' Wood Reed Grass* 1 0.10 •Suitable for forest access roads,skid Showy Tick Trefoil* 1 0.10 trails and other partial shade'situations. 11 Moist Creeping Bentgrass . 5 0.10 * Use Cool Season planting procedure. i Wet Bluejoint Reed Grass 1. 0.10 •Suitable for waterways,pond or ditch banks. Virginia Wild Rye 3 0.10_ *Trefoil requires inoculation with nitrogen fixing bacteria. Fowl Meadow Grass 10 . 0.25 Showy Tick Trefoil* 1 0.10 Red Top 1 0.10 12 Wet Blue Joint Reed Grass 1 ' 0.10 `.Use Cool Season planting procedure.. Canada Manna Grass 1 0.10 'OK to seed in saturated soil i conditions,but not in standing water. Rice Cut Grass 1 0.10 Creeping Bent Grass 5 0:10 `Suitable as stabilization seeding for ' created wetland: Fowl Meadow Grass 5 0.10 *All species in this mix are native to Massachusetts. i 13 Dry- American Beachgrass 18" 18, *Vegetative planting with dormant culms,M culms per planting Moist centers centers 14 Inter- Smooth Cordgrassl2-18 12-18" •Vegetative planting with transplants. Tidal Saltmeadow Cordgrass centers centers Erosion and Sediment Control Guidelines 1 1 ' Erosion and Sediment Control Practices 139 Notes: Species such as Tumble Lovegrass,Fringed Bromegrass,Wood Reedgrass,Bush Clover and Beach Pea,while known to be commercially available from specific seed suppliers,may not always be available from your particular seed suppliers.The local Natural Resources Conservation Service office may be able to help with a source of supply.In the event a particular species listed in a mix can not be obtained,however,it may be possible to substitute another species. Seed mixtures by courtesy o/Nomml Resources Conservation Service,Amherst,MA. ' (PLS) Pure Live Seed Warm Season grass seed is sold and planted on the basis of pure live seed.An adjustment is made to the bulk rate of the seed to compensate for inert material and non-viable seed. Percent of pure live seed is calculated by multiplying the percent purity by the percent germination; (%purity)x(%germination)=percent PLS. ' For example, if the seeding rate calls for 10lbs./acre PLS and the seed lot has a purity of 70% and germination of 75%, the PIS factor is: (.70 x.75) =.53 10 lbs. divided by.53 = approx. 19 lbs. Therefore, 19 lbs of seed from the particular lot will need to be applied to obtain 10 lbs. of pure live seed. Special Note Tall Fescue,Reed Canary Grass, Crownvetch and Birdsfoot Trefoil are no longer recommended for general erosion control use in Massachusetts due to the invasive characteristics of each. If these species are used, it is recommended that the ecosystem of the site be analyzed for the effects species invasiveness may impose.The mixes listed in the above mixtures include either species native to Massachusetts or non-native species that are not perceived to be invasive, as per the Massachusetts Native Plant Advisory Committee. Wetlands Seed Mixtures For newly created wetlands,a wetlands specialist should design plantings to provide the best chance of success. Do not use introduced, invasive plants like reed canarygrass (Phalaris arundinacea) or purple loosestrife (Lythrum salicaria). Using plants such as these will cause many more problems than they will solve. ' The following grasses all thrive in wetland situations: ca Fresh Water Cordgrass(Spartina pectinate) cv Marsh/Creeping Bentgrass(Agrostis stoloni/era, var. Palustric) cz Broomsedge(Andropogon virginicus) cz Fringed Bromegrass(Bromus ciliatus) cz Blue Joint Reed Grass(Calamagrostis couedensis) 1 c e Fowl Meadow Grass(Glycerin striata) cg Riverbank Wild Rye(Elymus riparius) cis Rice Cutgrass(Leersia oryzoides) cz Stout Wood Reed(Cinno orundinacea) ' ca Canada Manna Grass(Glycerin canadensis) Erosion and Sediment Control Guidelines r 140 Erosion and Sediment Control Practices A sample wetlands seed mix developed by The New England ' Environmental Wetland Plant Nursery is shown on the following page. Wetland Seed Mixture r The New England Environmental Wetland Plant Nursery has developed a seed mixture which is specifically designed to be used in wetland replication projects and stormwater detention basins. It ' is composed of seeds from a variety of indigenous wetland species. Establishing a native wetland plant understory in these areas provides quick erosion control, wildlife food and cover, and helps to reduce the establishment of undesirable invasive species such as Phragmites and purple loosestrife(Lythrum salicaria).The species have been selected to represent varying degrees of drought tolerance, and will establish themselves based upon microtopography and the resulting variation in ' soil moisture. r r r r r r r r Erosion and Sediment Control Guidelines 1 I Erosion and Sediment Control Practices 141 ' Common Name (Scientific Name) %in Mix Comments Lurid Sedge 30 A low ground cover that tolerates mesic sites ' (Carex lurida) in addition to saturated areas; prolific seeder in second growing season. Fowl Meadow Grass 25 Prolific seed producer that is a valuable (Glycerin Canadensis) wildlife food source. ' I Fringed Sedge 10 A medium to large sedge that tolerates i (Carex crinita) saturated areas;good seed producer. t Joe-Pye Weed 10 Flowering plant that is valuable forwildlife ' t (Eupotoriadelphus maculatus) cover. Grows to 4 feet. t > Brook Sedge 10 Tolerates a wide range of hydrologic ' ! (Carex spp., Ouales group) conditions. Woolgrass 5 Tolerates fluctuating hydrology. (Scirpus cyperinus) Boneset 5 Flowering Plant that is valuable for wildlife ' (Eupatorium perfoliatum) cover. Grows to 3 feet. Tussock Sedge <5 Grows in elevated hummocks on wet sites, (Carex stricta) may grow rhizomonously on.drier sites; Blue Vervain <5 A native plant that bears attractive, blue (Verbena hastata) flowers. The recommended application rate is one pound per 5,000 square feet when used as an understory cover.. This rate should be increased to one pound per 2,500 square feet for detention basins and other sites which require a very dense cover. For best results,a late fall application is recommended.This mix is not recommended for standing water. 1 Erosion and Sediment Control Guidelines Guidelines On.Deicing Chemical(Road Salt) Storage Water, Wastewater& Wetlands MassDEP Page 1 of 2 t MassDEP Maeaachusette DeparGrhent of Errvhvnmental Protection i Guidelines On Deicing Chemical (Road Salt) Storage ' Bureau of Resource Protection Drinking Water Program Effective Date:December 19, 1997. Guideline No.DWSG97-1 Applicability:Applies to all parties storing road salt or other chemical deicing agents. Supersedes:Fact Shat:DEICING CHEMICAL(ROAD SALT)STORAGE(January 1996) Approved by:Arleen O'Donnell,Asst.Commissioner for Resource Protection PURPOSE:To summarize salt storage prohibition standards around drinking water supplies and current salt storage practices. APPLICABILITY:These guidelines are issued on behalf of the Bureau of Resource Protection's Drinking Water Program.They apply to all parties storing road salt or other chemical deicing agents. I �. I. The Road Salt Problem: Historically,there have been incidents in Massachusetts where improperly stored road salt I has polluted public and private drinking water supplies.Recognizing thebl pm em,state and local governments have taken steps in recent years to remediate impacted water supplies and to protect water supplies from fuhve contamination.As a result of properly designing I ' storage sheds,new incidents are uncommon.These guidelines summarize salt storage prohibition standards around drinking water supplies and current salt storage practices. I Salt Pile Restrictions in Water Supply Protection Areas: Uncovered storage of salt ls forbidden by Massachusetts General Law Chapter 95,section . 7A in areas that would threaten water supplies.The Drinking Water Regulations,310 CMR 22.21(2)(6),also restrict deicing chemical storage within wellhead protection areas(Zone I and Zone 11)for public water supply wells,as follows:"storage of sodium chloride, chemically treated abrasives or other chemicals used for the removal of ice and snow on mads[are prohibited],unless such storage is within a structure designed to prevent the generation and escape of contaminated nmoff or leachate."For drinking water reservoirs, 310 CMR 22.200 prohibits,through local bylaw,uncovered or uncontained storage of road or parking lot de-icing and sending materials within Zone A at new reservoirs and at those ' .reservoirs increasing their withdrawals under MGL Chapter 21G,the Water Management Act. For people on a low-sodium diet,20 mg/L of sodiuim in drinking water is consistent with the ' bottled water regulations'meaning of"sodium free."At 20 mgd,sodium contributes 100/6 or less to the sodium level in people on a sodium-restricted diet For more information hq://www.mass.gov/dep/water/laws/saitgui.htm 1/23/2012 i 1 Guidelines On DeicingChemical ) g g (Road Salt).Storage Water Wastewater& Wetlands MassDEP Pa a 2.of 2 contact:Catherine Samfnes at 617-556.1070 or catherine.samfinas@stme.maus,or Suzanne Robert at 617-292-5620 or suzanne.robert@smte.maus. III. Salt Storage Best Management Practices (BMP): Components of an-environmeat-friendly roadway deicing salt storage facility include: • the right site=a flat site; • adequate space for salt piles; ' • storage on a pad(imperviousrpaved area); storage under a roof;and • runoff collection/containment. I For more information,see The Salt Storage Handbook,6th ed.Virginia Salt Institute,2006 (phone 703-549-4648 or httpJ/twvw.sahinstitute.org/Publications-A-V/Salt-Storage- Handbook). IV. Salt Storage Practices of the Massachusetts Highway Department: The Massachusetts Highway Department(MED)has 216 permanent salt storage sheds at 109 locations in the state.On leased land and state land under arteries and ramps,where the MBD cannot build sheds,salt piles are stored under impermeable material.This account for an additional 15 sites.The MED also administers a program to assist municipalities with the construction of salt storage sheds.Of 351 communities,201 municipalities have used state funds for salt storage facilities. For more information about MHD's salt storage facilities,contact Paul Brown at the Massachusetts Highway Department,10 Park Placa,Boston,MA 02116(phone 617-973- 7792). 1 1 ' hq://www.mass.gov/dep/water/laws/saltgW.htin 1/23/2012 i_ ' Snow Disposal Guidance I Water, Wastewater& Wetlands I MassDEP Page 1 of 4 " MassDEP Meeaechumota Department of Envbanmentel PmtecUon i Snow Disposal Guidance Effective Date:March 8,2001 Guideline No.BRPG01-01 Applicability:Applies to all federal,state,regional and local agencies,as well as.to private businesses. Supersedes:BRP Snow Disposal Guideline BRPG97-1 issued 12/19/97,and all previous snow disposal guidance . ' Approved by:Glenn Haas,Assistant Commissioner for Resource Protection PURPOSE:To provide guidelines to all government agencies and private businesses regarding snow disposal site selection,site preparation and maintenance,and emergency ' snow disposal options that are acceptable to the Department of Environmental Protection, Bureau of Resource Protection: APPLICABIIdTY:These Guidelines are issued by the Bureau of Resource Protection on behalf of all Bureau Programs(including Drinking Water Supply,Wetlands and Waterways, Wastewater Management,and Watershed Planning and Permitting).They apply to public agencies and private businesses disposing of snow in the Commonwealth of Massachusetts. BdTRODUCITON Finding a place to dispose of collected snow poses a challenge to municipalities and ' businesses as they clear roads,parking lets,bridges,and sidewalks.While we are all aware of the threats to public safety caused by snow,collected snow that is contaminated with road salt,send litter,and sriomotive pollutants such as oil also threatens public health and the ' environment ! As snow melts,road salt,sand,litter,and other polluimts are transported into surface water or through the soil where they may eveptiiW reach the groundwater.Road salt and other pollutants can contaminate water supplies aud'eie toxie to atjtiatic life at certain levels.Sand washed into waterbodies can create sand bars or fill in wetlands and ponds,impacting I aquatic life,causing flooding,and affecting our use of dim resources. . i There are seveiarsteps that communities can take to minimize—the impacts of snow disposal : . . on public health and the enviroammt These steps will help communities avoid the costs of . a contaminated water supply,degraded waterbodics,and flooding.Everything we do on the land has the potantial to impact our water resources.Given the authority of.local goyergment over the use of the land,municipal officials and staff have a critically important..•.• :� rolgtaiplay In pmtootipg our water resources: i w ' The purpose of these gu)Aefines.is m•lelptnunicipelitiesand busmessos beloct,pffieparet and- n manntaapprtpriAte snow disposal'sites before the snow begins to eceumWate through the :r .r:;: .. .... 6ttp://www.mass.gov/dep/water/laws/snowdisp.htm 1/23/2012 ,. Snow Disposal Guidance I Water, Wastewater& Wetlands MassDEP Page 2 of 4 winter. ' RECOMMENDED GUIDELINES '!hese snow disposal guidelines address:(1)site selection;(2)site preparation and maintenance;and(3)emergency snow disposal. 1.SITE SELECTION ' The key to selecting effective snow disposal sites is to locate them adjacent to or on pervious surfaces in upland areas away from water resources and wells.At these locations, the snow meltwater can fitter into the soil,leaving behind sand and debris which can be . removed in the springtime.The following areas should be avoided: Avoid damping of snow into any waterbody,including rivers,the ocean,reservoirs, ponds,or wetlands.In addition to water quality impacts and flooding snow disposed of in open water wgcause navigational hazards when it freezes into ice blocks. • Do not dump snow within a Zone II or Interim Wellhead Protection Area(I WPA)of a public water supply well or within 75 feet of a private well,where road salt may contaminate water supplies. I . • Avoid duping snow on MassDEP-designated high and medium-yield aquifers where it may contaminate groundwater(see the next page for information on ordering maps from MassGIS showing the locations of aquifers,Zone B's,and IWPAs in your community). . • Avoid damping snow in sanitary landfills and gravel pits.Snow meltwater will create more contaminated leachate in landfills posing a greater risk to groundwater, and in gravel pits,Mere is little opportunity for pollutants to be filtered out of the meltwater because groundwater is close to the land surface. • Avoid disposing of snow on top of storm drain catch basins or in stormwater drainage swales or ditches.Snow combined with sand and debris may block a storm ' drainage system,causing localized flooding.A high volume of sand.sediment,and litter.relemed from melting snow also may be quickly.transported through the system into surface water. She Selection Procedures a It is important that the municipal Department of Public Works or Highway Depar[m®t Conservation Commission,and Board of Health work together to select appropriate snow disposal sites.The following steps should be taken: b. Estimate how much snow disposal capacity is needed for the season so that an adequate number of disposal sites can be selected and prepared c. Identify sites that could potentially be used for snow disposal such as municipal . open space(e.g.,parking lots or parks)- d. Sites located in upland locations that are not likely to impact sensitive environmental resources should be selected fust ' e. If more storage space is still needed,prioritize the sites with the least environmental impact(using the site selection criteria,and local or MassGIS maps as a guide). MassGIS Maps of Open Space and Water Resources ' If local maps do not show the information you need to select appropriate snow disposal . sites,you may order maps from MassGIS(Massachusetts Geographic Information System) ' which show publicly owned open spaces and approximate locations of sensitive environmental resources(locations should be field-verified where possible).DiNetent http://www.mass.gov/dep/water/laws/snowdisp.htm 1/23/2012 r ' Snow Disposal Guidance I Water, Wastewater&Wetlands I MassDEP Page 3 of 4 1 coverages or map themes depicting sensitive environmental resources are available from MassGIS on the map you order.At a minimum,you should order the Priority Resources Map.The Priority Resources Map includes aquifers,public water supplies,MassDEP- approved Zone II's,Interim Wellhead Protection Areas,Wetlands,Open Space,Areas of Critical Environmental Concern,NHESP Wetlands Habitats,MassDEP Permitted Solid Waste facilities,Surface Water Protection areas(Zone A's)and base map features.The cost of this map is$25.00.Other coverages or map themes you may consider,depending on the location of your city or town,include Outstanding Resource Waters and MassDEP Eelgrass - Resources.These are available at 525.00 each,with each map theme being depicted on a separate map.Maps should be ordered from MassGIS via the Internet at httplAvww.mass.gov/ingis.Maps may also be ordered by fax at(617)626-1249(order form available from the MassGIS web site)or mail.For further information,contact MassGIS at (617)626.1189. 2.SITE PREPARATION AND MAINTENANCE In addition to carefully selecting disposal sites before the winter begins,it is important to prepare and maintain these sites to maximize their effectiveness.The following maintenance measures should be undertaken for all snow disposal sites: • A silt fence or equivalent barrier should be placed securely on the downgedient side . of the snow disposal site. • To filter pollutants out of the meltwater,a 50-foot vegetative buffer strip should be maintained during the growth season between the disposal site and adjacent waterbodies. • Debris should be cleared from the site prior to using the site for snow disposal. • Debris should be cleared from the site and properly disposed of at the end of the snow season and no later than May 15. 3.EMERGENCY SNOW DISPOSAL As mentioned earlier,it is important to estimate the amount of snow disposal capacity you will need so that an adequate number of upland disposal sites can be selected and prepared. If despite your planning,upland disposal sites have been exhausted,snow may be disposed of near waterbodies.A vegetated buffer of at least 50 fed should still be maintained between the she and the waterbody in thesd situations.Furtlermore,it is essential than the other guidelines for preparing and maintaining snow disposal sites be followed to minimize the ` threat to adjacent waterbodies. . Under extraordinary conditions,when all land-based snow disposal options are exhausted, disposal of snow that is not obviously contaminated with road salt,sand,and other pollutants may be allowed in certain waterbodies under certain conditions.In these dire situations,notify your Conservation Commission and the appropriate MassDEP Regional Service Center before disposing of snow in a waterbody. ' Use the following guidelines in these emergency situations: • Dispose of snow in open water with adequate flow and mixing to prevent ice dams from forming. • Do not dispose of snow in saltmarshes,vegetated wetlands,certified vemal pools, shellfish beds,mudflats,drinking water reservoirs and their tributaries,Zone Hs or IWPAs of public water supply wells,Outstanding Resource Waters,or Areas of Critical Environmental Concent. hq://www_mass.gov/dep/water/laws/snowctisp.htm 1/23/2012 ' Snow Disposal Guidance. Water,.Wastewater&Wetlands I MassDEPPage 4 of 4 • Do not dispose of snow where trucks may cause shoreline damage or erosion ' . Coasuh with the municipal Conservation Commission to ensure that snow disposal in open water complies with local ordinances and bylaws. FOR MORE INFORMAMON If you creed mom information,contact one of MassDEP's Regional Service Centers: I Nortlreast Regional Office,Wilmington,978-694-3200 Southeast Regional Office,Lakeville,508-946.2714 ' Central Regional Office,Worcester,508.792-7683 Western Regional Office,Springfield,413-755-2214 or Call'flomas Maguire of DEP's Bureau of Resource Protection in Boston at 617-292-5602. i i t i 1 http://www.mass.gov/dep/watei/laws/snowdisp.htm, 1123/2012