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CLARK AVENUE SUBDIVISION ENVIRONMENTAL IMPACT STATEMENT - PLANNING � C\o-c� Awen� e Subdw �sio�1 - . Erv'�cQnrne.��-o-1 "ScnQack 5�ca.�Em�n�- � - ----- — 7 rI tApplicant: Project No. SALE-0026 NSD Realty Trust ' 76 Oakville Street Lynn, MA 01905 Environmental Impact Statement Proposed Cluster Residential Subdivision "The Woodlands" ' Clark Avenue Salem, Massachusetts August 14, 2015 -W, & MAMS S . . S 189 North Main Street,Suite 101 Midd1 ,MA 01949 RECEIVED978-539-8088 Ph 978-539$200 Fax ' AUL 2 / 2015 www.wsengineers.com ' DEPT.OF PLANNM Q COMW NTY DEVELOPMENT 1 1 ' Natural Environment 1. Air ' The principal source of dust is during the construction phase. Dust will result from drilling in rock areas and during placement of gravel road base.The project is not expected to generate ' any noticeable amount of smoke or odors. Wetting with water will be practiced over exposed soil areas to minimise dust,as may be required by weather conditions.Times of soil exposure will be relatively minimal due to the existence of shallow to exposed bedrock throughout the upland portions of the subdivision. ' The subdivision is bordered by existing homes on the west and north. According to the Salem Harbor wind and weather statistics, the prevailing winds vary in direction throughout the year ' with an average wind speed between 2 and 7 mph. No incineration will occur in the subdivision. 2. Land The site of the proposed subdivision is vacant.Topography is varied with surface slopes ranging from two to thirty-five percent.The site is wooded. Wetland resource areas are located in the south and north portions of the site. The major limitation posed by the land is shallow to exposed bedrock and slopes. Rock removal will be accomplished by blasting,which will be conducted in accordance with all applicable local and state regulations. No percolation tests were conducted on site since the subdivision twill connect to public sewer. Approximately 8.5 acres or 49 percent of the site will be altered by the construction of proposed ' roadways,dwellings and landscape areas. Lot 27 consists of 3.39 acres or 19.7 percent of the site and its developed characteristics have not yet been determined. All of the land is undeveloped ' woodland. Proposed grading plans have been designed to adapt to existing grading patterns to the maximum feasible extent.The grading design is depicted on Sheets 5 and 6 in the Definitive Plan set.Welland resource areas are similarly shown on Sheets 5 and 6 and are discussed in the ' next section of this document. 3. Water and Wetlands The proposed development for lots 1 through 26 is residential in nature.The major potential impact upon water quality would be from pollutants found in storm water runoff. Best Management Practices(BMPs) in accordance with Massachusetts DEP Storm Water Management Policy have,been incorporated into the subdivision design in order to improve ' runoff quality. 1 2 ' An erosion control plan for the construction period will be provided in the Stormwater Report to be submitted in a separate document as part of the Notice of Intent filing with the Conservation Commission. Stormwater Management The proposed stormwater management system includes surface and subsurface structures in order to prevent an increase in runoff rates from the site.Calculations for site runoff are ' included in the Mitigative Drainage Analysis,and,are summarized as follows: ' Description 24 hour Existing Proposed Type III Condition Condition 1 Storm Event Peak Rate of Peak Rate of (year) Runoff Runoff Q cfs. Q cfs. ' Flow 2 (3.1 inch) 5.1 4.6 towards 10(4.5 inch) 9.7 8.1 Clarke Ave. 100(6.5 inch) 17.0 13.3 ' Link 132L Flow 2 (3.1 inch) 7.6 6.9 towards the 10 (4.5 inch) 16.5 14.6 southern 100(6.5 inch) 31.0 27.3 wetlands Link 139L 1 Flow 2 (3.1 inch) 4.8 4.7 towards the 10 (4.5 inch) 11.3 9.3 northern 100(6.5 inch) 22.2 17.5 wetlands Link 128L Total flow 2 (3.1 inch) 12.1 11.2 ' discharging 10 (4.5 inch) 27.5 23A from project 100 (6.5 inch) 52.8 43.8 area ' Link 109L i t3 Stormwater management areas will be placed where topographically feasible and in places where there is opportunity for groundwater recharge to occur through the bottoms of the systems. Proposed sewage disposal will be into the existing City of Salem Municipal System. Since wastewater ultimately flows to the S.E.S.D. treatment plant and following treatment is discharged at sea,it is assumed that wastewater from the proposed subdivision will have no impact upon surface or groundwater supplies. 4. Energy 1 Energy will be supplied to the proposed subdivision in the form of underground electric&gas services provided by the appropriate utility companies. ' 5. Noise The most noticeable change in ambient noise levels will occur during the construction phase ' and will result from construction machinery,rock removal operations,and construction of the proposed dwellings. Construction days and hours of operation will adhere to the Ordinances of the City of Salem. Wildlife will likely be temporarily displaced by construction activity but will tend to reestablish following completion of work in the proposed open spaces. ' Once work is completed,ambient noise levels will be similar to those occurring in the existing residential neighborhoods abutting the subdivision. I �I 6. Local Flora and Fauna It is anticipated that upland habitat for mammals and songbirds will be disturbed during construction.Typically,those habitats re-establish after completion of construction. Existing vegetation will be removed in areas of proposed construction and new plantings installed as necessary for landscaping and screening purposes. The site is not located within the estimated habitat of rare wetlands wildlife as determined by reference to the Massachusetts Division of Wildlife Natural Heritage Mapping. 4 1 Man Made Environment 1. Land Use iThe site lies partially within an R-1 Zoning District(north of Clark Avenue)and partially within an Industrial Zoning District. Within the R-1 Zoning District,single family homes are an allowed use on lots having a minimum area of 15,000 square feet. Lots 1 through 26 are proposed as a Cluster Development under Section 7-14 of Salem Zoning Ordinance in order to preserve both wetland and upland open space. Lot 27,located off of Road A,consists of 3.397 acres,of which,2.962 acres he within the Industrial Zone. Development of that lot will be reviewed under Section 7-18 of the Salem Zoning Ordinance. Land use to the north and west of the site is typically for single family homes. Land to the south ' and east of the site is undeveloped and privately or municipally owned. There are no existing public open areas within the perimeter of the subdivision. An area of open ' space,comprising a land area of 6.967 acres is proposed.That land will be available for recreational use by the residents of the city. 1 Major shopping and service facilities are located within.5 to 1.5 miles of the site on Highland Avenue.The approximate relationship of the site to public educational facilities is as follows: Witchcraft Heights Elementary School-2.5 miles Collins Middle School-2.3 miles Salem High School-1.8 miles MBTA Service is available within.3 miles of the site on Highland Avenue.Recreational facilities ' are located throughout the City within.75 to approximately 4 miles of the site. 2. Density Proposed dwellings in the cluster subdivision (Lots 1-26)are expected to be approximately 1,500 square feet in ground coverage and will contain 3 to 4 bedrooms. All dwellings will be serviced by an individual driveway and include a two car garage. Proposed development characteristics of Lot 27 have not been determined at this time. 1 I 5 1 i iTABLE OF PROPOSED SITE COVERAGE Total Site Area=17.229 Acres iCover Type Area (Ac) Percent Coverage iDwellings 0.895 5.2 Area within Roads A& B 1.472 8.5 iDriveways 0.325 1.9 Dedicated Open Space 6.967 40.4 Individual Yard Areas 4.173 24.2 ' Undetermined (Lot 27) 3.397 19.8 Total:17.229 Ac. 100.0 3. Zoning iThe site and surrounding parcels are located in the R-1 and Industrial Zoning Districts. As previously discussed,Lots 1 through 26 in the proposed subdivision are being applied for under i the Cluster Provisions of Section 7-14 of the Salem Zoning Ordinance. Minimum individual lot dimensional characteristics that follow are the same as shown on the previously approved plans: Lot Area (None) Lot Width (None) Lot Coverage 30% i Front Yard 15 Feet Side Yard 10 Feet Rear Yard 30 Feet iBuilding Height 35 Feet Conventional zoning dimensional characteristics are as follows: Residential one-family (LU) Industrial(1)) Lot Area 15,000 square feet 40,000 square feet Lot Width 100 feet 150 feet i Lot Coverage 30% 45% Front Yard 15 feet 30 feet Side Yard 10 feet 30 feet i Rear Yard 30 feet 30 feet Building Height 35 feet 45 feet 6 i 4. Architecture Proposed dwellings are to be two story,wood frame construction on concrete foundations. Each dwelling will contain a two car garage and 3 to 4 bedrooms. Visual impacts from properties adjacent to the site will be buffered by proposed open space areas. Two of the proposed homes will be approximately 70-80 feet from the existing homes on Clark Avenue Extension. The remaining proposed homes will be over 100' to any of the existing homes located on Clark Avenue and Clark Avenue Extension. 5. Historic Buildings,Historical Sites,and Archeological Sites iThere are no known historical buildings or sites or archeological sites on or immediately adjacent to the site to the best of our knowledge. It should be noted that there is evidence of an 1 old foundation and walls that exist on the property currently. Public Facilities 1. Water supply,flow pressure and distribution. The source of water to be supplied to the subdivision is municipal,as delivered by the City of Salem. Water mains will be 8 inch diameter,cement-lined ductile iron and will be located in the subdivision as depicted on the Definitive Plans.The twenty-six proposed dwellings are expected to have an average daily demand of 10,000 gallons and a peak demand of approximately 45 gallons per minute based on an average of 3.5 bedrooms per dwelling and 110 gallons per bedroom per day. Firefighting demand is estimated to be 750 gallons per minute (calculation to be verified with static pressure testing by applicant). I2. Sanitary Sewerage Sanitary sewerage facilities,within the proposed subdivision,will consist of an eight-inch(8") ' polyvinyl chloride (PVC)gravity force sewer line that will connect to the existing gravity sewer located on Clark Avenue as shown on the definitive plans. Each dwelling will be serviced by an individual four or six inch gravity connection. It is anticipated that upon acceptance of streets 1 by the City of Salem, the gravity sewer within the street will be maintained by the Department of Public Works. Expected wastewater volumes and flows approximately are as follows: Average Daily Flow: ±10,000 Gallons Peak Daily Flow: ±45 Gallons per minute The proposed wastewater discharge is not anticipated to have a measurable impact upon ' existing public facilities. 7 i3. Storm Drainage Facilities Street drainage will consist of a series of piped manholes and catch basins leading to stormwater management areas to be located in the open space parcels and one subsurface facility to be located on Lot 12.The street drainage system has been designed with the minimum capacity for a ten year storm. Stormwater management areas have been designed to prevent any runoff increase for two, ten or one hundred year storms,consistent.with Massachusetts DEP Stormwater Management Policy. Runoff from the site will discharge into existing wetlands. 1 Calculations for the design of the various elements of the storm drainage system are provided in the Mitigative Drainage Analysis dated August 14,2015 by Williams&Sparages. 1 4. Disposition of Stormwater See definitive plans for locations of stormwater management areas and outfalls.See Mitigative Drainage Analysis for more information on rates of runoff and quantity of stormwater to be discharged. ' S. Refuse Disposal On average,it is estimated that the 26 homes would generate approximately 80 tons of residential solid waste annually according to the EPA website.Of this,approximately 34% is recycled and composted on average. Collection and disposal of solid waste would be accomplished by the City of Salem Municipal Contractor. 1 Construction debris will be kept in on site dumpsters and disposed of by licensed private contractors. Brush will be chipped and used for mulch and/or temporary slope stabilization or ' trail construction. ' 6. Traffic Facilities Traffic entering and leaving the subdivision will access Highland Avenue by way of Clark Avenue and Barnes Road. Based on I.T.E. Land Use Code 210,an average daily trip generation rate of 260 trips (10.0/unit)would be projected. From the 26 homes,pedestrian circulation is provided by means of sidewalks on each side of the proposed roadways. Each dwelling is expected to have a two car garage and two driveway spaces. 7. Electric Power ' The twenty-six dwellings comprising the proposed subdivision will receive electric power from the National Grid by means of a new underground distribution system. The average Massachusetts home is expected to require approximately 627 kWh/month according to electricitylocal.com. t 8 I 1 8. Gas INatural Gas will be extended into subdivision from Clark Avenue. It is expected that all homes will be heated with natural gas. It is likely that the majority of homes will also utilize gas for Icooking and clothes drying as well. ICommunes Services 1. Schools IIt is estimated that the 26 homes in the proposed subdivision would result in 35 to 40 students if all future residents were new to Salem. IDistances from the site to existing public school areas are as follows: Witchcraft Heights School-2.5 miles Collins Middle School-2.3 miles Salem High School-1.8 miles 2. Recreation The site is currently in private ownership and is thus unavailable for public use and/or recreational facilities.The 6.967 acres of the site to be preserved as open space will be available for access to the residents of Salem.Sidewalks are proposed throughout the subdivision and a trail system will be constructed on the north-side of the site and connect to adjacent land to the east owned by the City of Salem. 3. Police Based on the 26 new homes proposed for the subdivision,a population of approximately 100 I persons would be anticipated. Based on two cars per dwelling,approximately 52 cars would be expected.Traffic impact is discussed in a previous section of this document. 4. Fire Twenty six wood-frames,two story single family dwellings are proposed in the subdivision. As discussed in the Public Facilities section of this document,a firefighting volume in excess of 750 gallons per minute,with a residual pressure of 20 pounds per square inch is projected.The source of that water is municipal supply from the City of Salem. Fire hydrant flow test data will ' be provided under separate cover when completed. 9 � 1 1 1 5. Public Works 1 Two (2)new roadways having a total length of 1,388.02 feet are proposed. Proposed utility characteristics are summarized as follows: 1 Gravity Sewer 1,440±LF Water Main 1,400±LF 1 Storm Drain 1,230±LF Human Considerations 1. Aesthetics and Visual Impact The character of the area within which the proposed subdivision is proposed will change since the parcel is now vacant.The proposed single family homes will be in keeping with the 1 character of the surrounding developed property.The density of the proposed development is consistent with the requirements of the Salem Zoning Ordinance. Proposed open space preservation and distance of proposed homes from existing will help diminish impacts on the 1 surrounding neighborhood. 2. Parks,Forests,and Recreational Areas ' No portion of the site is currently available for public use.The cluster development proposal would preserve 6.967 acres,or,40.4% as open space to which residents of the City would have 1 access. 3. Public Health Any existing debris on site will be cleaned up and disposed of lawfully as construction progresses. Rodent control will be managed by a licensed exterminator in accordance with the 1 project needs. No debris,stumps,or other wastes resultant from the project will be buried or otherwise disposed of on site. i I 10 1 1 Applicant: Project No. SALE-0026 1 NSD Realty Trust 76 Oakville Street Lynn, MA 01905 1 1 Mitigative Drainage Analysis 1 Proposed Cluster 1 Residential Subdivision 1 "The Woodlands" 1 1 Clark Avenue Salem, Massachusetts 1 1 August 14, 2015 1 � ' -W-C WILLIAMS & SPARAGES T S 189 North Main Street,Suite 101 Middleton,MA 01949 978-539-8088 Ph 978-539-8200 Fax www.wsen�neers.com PETER3` 11A OF MASS9 Proposed Cluster Residential Subdivision oy "The Woodlands", Salem, MA BLA SDEL,JR. m ' August 14, 2015 0CIVIL y No.41613 Purpose: ° / TF �Q 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. Introduction: I 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/D 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"Road A", the second is a two hundred ninety-nine (298.99) shown on the plans as Road B in order to provide access to a twenty-seven lot subdivision. Lots 1 through 26 are in the R1 ' Zone and will be a cluster residential subdivision, Lot 27 lies in both the R1 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 Idetention basins,a subsurface infiltration area,water services and other various utilities. It should be noted that there are wetland resource areas located on the subject property and there ' are proposed activities within the one-hundred(10(')buffer zone to the edge of bordering vegetated wetlands. Therefore,a Notice of Intent(NOD filing will be filed with the Salem Conservation Commission at a later date. ' Existing Condition Soils Analysis: In 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 well as 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 1 Proposed Cluster Residential Subdivision "The Woodlands", Salem, MA August 14, 2015 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 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. For 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 Conservation Commissioners, March 2002 Table 2-1. tStormwater Modeling Methodology: The mathematical model used in this analysis was provided using the HydroCAD 9.10 Version developed by HydroCAD Software Solutions LLC. HydroCAD is a program that is used to model 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. HydroCAD 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 desired conditions as well as to predict flooding or other impacts at specified locations such as ' erosion. Three (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. Existing Condition Watershed: 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. Using 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 i ' storm events are included in this report. 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. ' 3 Proposed Cluster Residential Subdivision "The Woodlands", Salem, MA August 14, 2015 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. i Pretreatment for the subsurface infiltration system will be through the use of the deep-sump catch basins with hoods and 1,500 gallon sediment&oil separator unit. The remaining stormwater management areas will receive pretreatment from deep-sump catch basins and sediment forebays ' 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 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 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. ' 4 Proposed Cluster Residential Subdivision "The Woodlands", Salem, MA August 14, 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 southern 10 (4.5 inch) 16.5 14.6 wetlands 100 (6.5 inch) 31.0 27.3 Link 139L ' Flow towards 2 (3.1 inch) 4.8 4.7 the northern 10 (4.5 inch) 11.3 9.3 wetlands 100 (6.5 inch) 22.2 17.5 ' Link 128L Total flow 2 (3.1 inch) 12.1 11.2 discharging 10 (4.5 inch) 27.5 23.4 from project 100 (6.5 inch) 52.8 43.8 area Link 109L I ' 5 1 Proposed Cluster Residential Subdivision "The Woodlands", Salem, MA August 14, 2015 Comparison Table Total Peak Rate tributary to non-jurisdictional 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 i � 1 6 ' Proposed Cluster Residential Subdivision "The Woodlands", Salem, MA ' August 14, 2015 ' Proposed Subsurface Infiltration Area MdroCAD Pond 78P (40) Cultec Recharger 330XL HD Units- 7 rows of 7 units ' Top of Stone=125.94 (25.67x58.0(Y) Top of Chambers=125.44 12" Inv. In=124.33 ' Bottom of Chambers=122.90 Bottom of 6" Stone bed=122.40 t 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 0.26 125.56 t100 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. ' "This 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. ; 1 7 I 1 '. Proposed Cluster Residential Subdivision "The Woodlands", Salem, MA ' August 14, 2015 ' Detention Pond 1 HydroCAD Pond 142P 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 Q 132.50 ' 8" Orifice Q 134.00 10" Orifice Q 134.50 12" RCP Inv.Out--131.50 1 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 1 (YR) (Qin) cfs. (Discarded) RCP Stone Outflow Level (W.L.) ft. Spill ' 2 2.0 0.01 0.49 0.0 0.50 134.01 ' 10 '3.8 0.01 1.70 0.0 1.72 134.68 100 6.6 0.02 4.00 0.0 4.01 135.31 ' *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 i t 8 ' Proposed Cluster Residential Subdivision "The Woodlands", Salem, MA ' August 14, 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 ' 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. Spill a 2 2.0 0.02 0.16 0.0 0.18 129.53 10 3.4 0.02 0.21 0.0 0.24 130.28 ' 100 5.5 0.03 0.27 0.0 0.30 131.30 *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 1 9 ' Proposed Cluster Residential Subdivision "The Woodlands", Salem, MA IAugust 14, 2015 t 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 Q 115.50 ' 12" RCP Inv. Out--113.50 1 Peak Rate of Runoff Out 24 hour Type III Peak Rate of (Qout) cfs. ' Storm Event Runoff In `Infiltration 12" 81L Total Peak Water (YR) (Qin) cfs. (Discarded) RCP Stone Outflow Level (W.L.) ft. S illwa I2 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 i ' 100 6.6 0.02 2.07 0.0 2.10 117.35 1 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 1 ' 10 1 ' Proposed Cluster Residential Subdivision "The Woodlands", Salem, MA August 14, 2015 I Detention Pond 4 HydroCAD Pond 144P ' Top of Berm=122.5 Proposed Outlet Control Structure Bottom of Berm=117.0 Rim=122.5 8'L Emergency Stone Spillway=122.0 18" Pipe level @ 117.50 12" RCP FES Inv. In=122.00 (From Road A) 6" Orifice @ 117.50 8" Orifice @ 120.50 ' 12" RCP Inv. Out--114.50 ' 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. 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 i ' j *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 ' 11 1 I 1 ' 1 1 1 1 1 1 Existing Condition 1 Watershed Analysis 1 t 1 1 1 1 1 1 1 1 1 ire; 138S EX�3 EX-RES 1� 132- � 139 4 ' 13ZS' atch b Gso existing Raton t exlsrvg �,;; catch bases on Garb wetlands to sadh Avarua EX-2 Rurorf towards Isdated EXA Wetland W sodas . �t1U�S EX-1 14 A_, 140S lov2rtls Wdsft Total91'V fa Runofi Rwaff towarQs sad. EX-5 / wetlands to de rvth d'aohargGg Gan Ore1ed Welland'C'series area ' 143S KaT EX-RES 2 i 1 'SUbCat Reach , ,:Ott fLlFlk; Drainage Diagram for existing-submittal Prepared by Microsoft. Printed 8/18/2015 HydroCAD®8.10 stn 06611 0 2010 HydroCAD Software Solutions LLC Existing Condition Watershed Analysis - Clark Avenue, Salem MA existing-submittal ' Prepared by Microsoft Printed 8/18/2015 HydroCAD®9.10 s/n 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 (111 S, 136S, 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 ' 1 1 i it Existing Condition Watershed Analysis - Clark Avenue, Salem MA existing-submittal Prepared by Microsoft Printed 8/18/2015 HydroCAD®9.10 s/n 06611 @2010 HydroCAD Software Solutions LLC Page 3 iSoil Listing (all nodes) ' Area Soil Subcatchment (sq-ft) Group Numbers 0 HSG A 0 HSG B 872,510 HSG C 111S, 1365, 137S, 1385, 140S, 142S, 143S 0 HSG D ' 0 Other 872,510 TOTAL AREA i t 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 HydroCAD®9.10 s/n 06611 @2010 HydroCAD Software Solutions LLC Pape 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 Dyn-Stor-Ind method , Subcatchment 111 S: 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 cfs 20,440 cf 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 cfs 3,170 cf 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 cfs 8,203 cf 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 cfs 14,234 cf 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 cfs 3,202 cf Subcatchment 142S: EX-RES 1 Runoff Area=93,234 sf 45.71% Impervious Runoff Depth=1.67" ' Flow Length=300' Tc=5.0 min CN=85 Runoff=4.20 cfs 12,995 cf Subcatchment 143S: EX-RES 2 Runoff Area=12,285 sf 30.00% Impervious Runoff Depth=1.39" ' Flow Length=105' Tc=5.0 min CN=81 Runoff=0.46 cfs 1,424 cf Link 1091-: Total Surface Runoff discharging from project area Inflow=12.10 cfs 57,296 cf Primary=12.10 cfs 57,296 cf ' Link 128L: Runoff towards existing wetlands to the north Inflow--4.78 cfs 21,864 cf Primary-4.78 cfs 21,864 cf , Link 130L: Runoff towards Isolated Wetland "B"series Inflow--0.69 cfs 3,170 cf Primary--0.69 cfs 3,170 cf ' Link 132L: Runoff into existing catch basins on Clark Avenue Inflow--5.09 cfs 21,199 cf Primary--5.09 cfs 21,199 cf Link 139L: Runoff towards existing wetlands to the south Inflow--7.62 cfs 35,433 cf ' Primary=7.62 cfs 35,433 cf Link 141 L: Runoff towards Isolated Wetland "C series Inflow--0.73 cfs 3,202 cf ' Primary--0.73 cfs 3,202 cf Total Runoff Area=872,510 sf Runoff Volume=63,668 cf Average Runoff Depth =0.88" 94.69%Pervious 826,204 sf 5.31% Impervious=46,306 sf I Existing Condition Watershed Analysis - Clark Avenue, Salem MA I existing-submittal Type ///24-hr 2 yr Rainf611=3.10" Prepared by Microsoft Printed 8/18/2015 HydroCAD@ 9.10 s/n 06611 @2010 HvdroCAD Software Solutions LLC Paoe'5 Summary for Subcatchment 111 S: EX-1 Runoff = 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 ' Type III 24-hr 2 yr Rainfall=3.10" Area (so CN Description 318,326 70 Woods, Good, HSG C ' 318,326 100.00% Pervious Area 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" 0.9 330 0.1500 6.24 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 13.4 430 Total ' Subcatchment 111S: EX-1 Hydrograph 5. i i O Runoff -- -- --- -- -- . . .. 2yy------ ' Ty:•pe III: 4 =31O;r' Rai Infal l: a=3 3 . `R • ;n 0 ff Vp!IOme: 20;440i---d- f RUh6 f Depth"�0 77" T ....F low Le:ngi`h;-43�"--- 2 ■ CNi _70, 0 0 1 2 3 4 5 6 7 8 9 10111213141516,1711111202122 23242526272829303132 3334353637383940 Time (hours) 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 Paae 6 Summary for Subcatchment 136S: EX-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 (sf) CN Description 49,366 70 Woods, Good, HSG C , 49,366 100.00% Pervious Area 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 Subcatchment 136S: EX-4 Hydrograph 0.75 ! ! i t i D Runoff i 0.7 ' :oma m. 0.65 Type: IfF24=fir 2yr 0.6 3x100 i : ; ; : • 0.55 i 0.5 12u toff Area493!66 sf! 0.45 Ru'n'o"f#Volume=3;1:70; cf 0.4 ; RAJI Depth=0 7 '' LL 0.35 .-:. 1..;..1..!..1..1 [ �.. ..i ' �1.. .0.3- Flow Len'gtFl= 20 ' 0.25- 0.2. .25 o.z • 0s 0.1 0.05 0 1 2 3 4 5 6 7 8 9 10111213141516171819202,22232425262728293031323334 353637383940 Time (hours) 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 7 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-hr 2 yr Rainfall=3.10" Area (so CN Description 127,758 70 Woods, Good, HSG C 127,758 100.00% Pervious Area Tc Length Slope Velocity Capacity Description (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 15.6 475 Total Subcatchment 137S: EX-2 Hydrograph 0 Runo6 Typ,# 01:24 he 2 yr ■ Rainfall=3:1;0:"' ■ ' Rrulnoff Area=127 758 sf - - -- ___ t- n_ Volume=8203cf R - tlnoffRepth"07To Flow l e;ngth-475 '; TC--! 6 min' ' CN:=70 0 1 2 3 4 5 6 7 8 9 10 11 1213141516 17 18 19 20 21 22 23 24 25 26 27 2'8"2"9 30 31"32"'33"34'35"'36''37' 38 39 40 Time (hours) r Existing Condition Watershed Analysis - Clark Avenue, Salem MA , existing-submittal Type ///24-hr 2 yr Rainfall=3.10" Prepared by Microsoft IPrinted 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 (sf) 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 1TY.-, ;ilk- 1; ; 3 i t Rainfall=3:10"' ' Runoff At4zi 221 6'79;sf - - _ - � - Runoff-Volume' 14;234;.;.-cf! - RUhbff Depth"0:77 Flow Length=470'; : :.., c= '� 1 CN:=70 , 0 .. . •0 1. 2 3 4 5 6 7 8 9 1011121314151617 1819202122 23242526272829303132 33343536373B 3940 Time (hours) 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 HvdroCAD Software Solutions LLC Paae 9 ' Summary for Subcatchment 14OS: EX-5 tRunoff = 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) (f 1sec) (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 ' Subcatchment 140S: EX-5 Hydrograph 0.8 0.75 . 0.7 . 0 Runoff Type �llr24hr 2yr 9.65 - 0.6 -310"' - 0.55 ' a=49 ..-urtoff Are'- : r_;$62 i.. - 1 off V` o tame; 3 -202 cf 0.4 , h:OL77,." u. 0.35 _ ...... .... i..i - Flow Length=560 :; , , . , . . , . . . - 0.2s = . 2. 0.2 ' 0.15- 0.1. .15 0.1 ' 0.05 i i i .; ! .' __• .; . .. ...' . ...'. .;..,.. . . .,.. .�..:. . .. 01 2' 3' 4 5 6' 7 8'9'1O 111.2 1 1 31.41.51 1 6-1.7..1.8..I,9..20 2122 23 24 25 26 27 28 29 30..3 1 1..3 1 2 33 34 35 36 37 38 39 40 Time (hours) 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 Pape 10 Summary for Subcatchment 142S: EX-RES 1 [49] Hint: Tc<2dt may require smaller dt i 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 1 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 ' 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 11 ' Subcatchment 142S: EX-RES 1 Hydrograph O RunoN 4 - - - - pe.1;1.11:24.ht-2 yr` .. Rani rfal 1=3:1:0:"' IIA: sf - ..' offAre,"a' .. i : ;Runoff, V'o':Itame; '12;995; cf! _3 .. .. R th6ffDeph 1 67 LL 2 - . . . . : 9&-30 Ori.. Flow Le:n' E� -- -- --- - - 7`c='5.0 'min; CN ;85 ' 0 1 2 3 4 5 6 7 8 9 1011 12 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 (hours) 1 1 1 t 1 Existing Condition Watershed Analysis - Clark Avenue, Salem MA ' existing-submittal Type 11124-hr 2 yr Rainfall=3.10" Prepared by Microsoft Printed 8/18/2015 HydroCAD®9.10 s/n 06611 @K10 HydroCAD Software Solutions LLC Page 12 Summary for Subcatchment 143S: EX-RES 2 1 [49] Hint: Tc<2dt may require smaller dt , Runoff = 0.46 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 ' 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 ' 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 Subcatchment 143S: EX-RES 2 ' Hydrograph . --;-- . 0.48 _;..y..p..;.-,__p__r..:..;.. a16 ea : • __ __ __ __ _ _ ___ _ _ __ __ __ ___ _ _ . : 7 1 '. ` -_-:-. 0.46 -_ _ _ ............... _ ;...; 0.44 . ..;..;...;.. . • .;.. , ,.. .. .. :.;.:TYPe :11124�hr::2y.r; . 0.42 _ .......................... 0.4 , - -- - - ll=3 1i0- 0.36 T--i- ....... ^--- -- - - - -- -- -- -- -- -- -- --- - - - -- --------- r ` 0.36 :..:............ - - �IZ ':n ` :ff:Ar a`::1: 85sf.�:: 0.32 ;...:..:..:..:..:...:..:.:.:.. i..i.u.i ° :.. ..Q,-:_-.t.-i .-.. : 0.3 LL--;-- --:---- ;--�- -- --- - --Rui�'off-Voltarne=124-cfs-- .. 00..2286 .. . . . = = = _.i ; ; = -- 6.24 ..;;. .. IZtari:of :Depth-=1:;;397. L 0.22 0.2 FlOvil= ...Mh-1-05-; = - - -- 0.16 . :..:....:....._,.::..,... _ Tc' ;5�:0 min: 0.14 ..:....................:.....:..... - - 0.12 . . 0.1 0.66 --i------ ----.-' - .. .0.06 - - ..i:. - - - - - - - - -- - -- -- - - - - - - 6.04 ,._-,.-. • .. . ... - - 0.02 ' 0 0 1 2 3 4 5 6 7 8 9101112131415161718,9202122 23242526272829303132 3334353637383940 Time (hours) ' 1 1 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 H_ydroCAD@ 9.10 s/n 06611 @2010 HydroCAD Software Solutions LLC Page 13 ' Summary for Link 109L: 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 13 -+-->'.--{-- - ..t. 12 - --- . - --- - - - - - El Primary ua .. 12 --:--T-'-'-"""�-- ------ - 6# - - - - -- -- f 0 -A r :e� --7-x;282- sf -- , . , 3 i • 1 0 1 2 3 4 5 6 7 8 9 10111213141516171819202122232425262728293031323334353637383940 Time (houm) 1 1 f 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 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, Inflow Depth = 0.79" for 2 yr event Inflow = 4.78 cfs @ 12.21 hrs, Volume= 21,864 cf 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 128L: Runoff towards existing wetlands to the north Hydrograph -- - -- - - - - ... •rer -----------a. --� ' ' f- 7 Fm Inflow • . � � � : 0 Primary 5 f a-3 IowAre 30;61'1 sf ' 4 1 y 3 3 a l . • LL r 2 i i 1 0 1 2 3 4 5 6 7 8 9 10111213141516171819202122232425262728293031323334353637383940 Time (hours) 1 1 Existing Condition Watershed Analysis - Clark Avenue, Salem MA 1 existing-submittal Type ///24-hr 2 yr Rainfall=3.10" Prepared by Microsoft Printed 8/18/20.15 HydroCAD@ 9.10 s/n 06611 @2010 HydroCAD Software Solutions LLC Page 15 ' Summary for Link 130L: Runoff towards Isolated Wetland "Brr 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 ■Inflow ' 0.75 - � _ _ __ _ __ _ a-4 0.65 l:nfl:ouv _Are' _ '9: 3:66:af..: :: 0.55 0.5 .. 0.45 -�- --�- -- -- -- A--'-- --F--i.. -- -4--{........--4--` 0.4 u 0.35 0.3 - - - --- - -- --- - - -- - - - - --- - — - -- - - - - i-. S .i 0.25 :..:..:. ..;..;.. ..i.. ..<.. ........... 0.2 i.: ..i..j.. 0.15 .� : I ;..j...y..;..I_�..i_�_-•__�_�_.1..:...:.. .. .::...:_�_�.. ... ..?.. . 0.17 0.0501, 0 1 2 3 4 5 6 7 8 910111213141516171819202122232425262728293031323334353637383940 Time (hours) t 1 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 HydroCAD@ 9.10 s/n 06611 @2010 HydroCAD Software Solutions LLC Page 16 . Summary for Link 132L: Runoff into existing catch basins on Clark Avenue ' Inflow Area P 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 ? : ®Inflow : A"� s maty nflow Are ' - 0 99:2 :sf! O Pri 5 4 : 3 _ _ _ i i 2- 100 1 , r 0 ... 0 1 2 3 4 5 6 7 8 9 10111213141516171819202122232425262728293031323334353637383940 Time (hours) 1 Existing Condition Watershed Analysis - Clark Avenue, Salem MA 1 existing-submittal Type 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 Pa-ge 17 . ' Summary for Link 139L: Runoff towards existing wetlands to.the south ' 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 cfs @ 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 ----------- - --- 0 Primary 8 �. nflow A ea6 442 67� sf 7 6 E i i i ,'-:-- --i..;-- -- --{-- - .4-4.....-...j-A------------ ---F-- ----F-4-1--- 4- 3-' --i- --4 i - - - - -- -- -- -- - 1 0 1 2 3 4 5 6 7 8 9 1011121314151617181920212223242526272829 1.3031323334353637383940 Time (hours) 1 Existing Condition Watershed Analysis - Clark Avenue, Salem MA existing-submittal Type lir 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 Pape 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 "Cr series ' Hydrograph - --- -- - - - - ' - - H inflow 0.8 _:o.re ae:- - - - -- 0 Primary . 0.75 a_4 4Td 0.7 : - ... : f I'r�f�'ornc 62 s.f. .. __j.. ..4__;--- _.•,..{..;.. ;..4.-;.......{..4------;-4-- 0.65 -;--;-.4__0.65 i 0.6 0.5 I F 0.45 .i. ii 0.4 �. 0.35 0.3 0.25 .. .. .. ...: 1: i ! i i 0.2 ' 0.15 . . 0.1 0.05 ' 0 1 2 3 4 5 6 7 8 910111213141516171819202122232425262728293031323334353637383940 Time (hours) i I 1 Existing Condition Watershed Analysis - Clark Avenue, Salem MA 1 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 1 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 cfs 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 cfs 6,955 cf ' Subcatchment 142S: EX-RES 1 Runoff Area=93,234 sf 45.71% Impervious Runoff Depth=2.91" Flow Length=300' Tc=5.0 min CN=85 Runoff=7.30 cfs 22,602 cf Subcatchment 143S: EX-RES 2 Runoff Area=12,285 sf 30.00% Impervious Runoff Depth=2.55" 1 Flow Length=105' Tc=5.0 min CN=81 Runoff=0.84 cfs 2,609 cf Link 109L: Total Surface Runoff discharging from project area Inflow=27.50 cfs 118,350 cf Primary=27.50 cfs 118,350 cf Link 128L: Runoff towards existing wetlands to the north Inflow=11.32 cfs 47,008 cf ' Primary=11.32 cfs 47,008 cf Link 130L: Runoff towards Isolated Wetland "B" series Inflow--1.65 cfs 6,886 cf Primary--1.65 cfs 6,886 cf Link 132L: Runoff into existing catch basins on Clark Avenue Inflow--9.74 cfs 40,422 cf Primary--9.74 cfs 40,422 cf Link 139L: Runoff towards existing wetlands to the south Inflow--16.51 cfs 71,342 cf " Primary--16.51 cfs 71,342 cf Link 141L: Runoff towards Isolated Wetland "C" series Inflow--1.74 cfs 6,955 cf Primary--1.74 cfs 6,955 cf ' Total Runoff Area= 872,510 sf Runoff Volume= 132,190cf Average Runoff Depth = 1.82" 94.69% Pervious =826,204 sf 5.31%Impervious=46,306 sf 1 1 Existing Condition Watershed Analysis - Clark Avenue, Salem MA ' existing-submittal Type 11124-hr 100 yr Rainfall=6.50" Prepared by Microsoft Printed 8/18/2015 HydroCAD®9.10 s/n 06611 @2010 HydroCAD Software Solutions LLC Page 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 cfs 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 cfs 34,144 cf Subcatchment 138S: EX-3 Runoff Area=221,679 sf 0.00% Impervious Runoff Depth=3.21" ' Flow Length=470' Tc=11.9 min CN=70 Runoff=15.61 cfs 59,245 cf Subcatchment 14OS: EX-5 Runoff Area=49,862 sf 0.00% Impervious Runoff Depth=3.21" ' Flow Length=560' Tc=12.3 min CN=70 Runoff=3.47 cfs 13,326 cf 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 cfs 37,107 cf 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 cfs 4,445 cf Link 109L: Total Surface Runoff discharging from project area Inflow--52.76 cfs 220,017 cf Primary--52.76 cfs 220,017 cf ' Link 128L: Runoff towards existing wetlands to the north Inflow--22.23 cfs 89,520 cf Primary--22.23 cfs 89,520 cf Link 130L: Runoff towards Isolated Wetland "B"series Inflow--3.26 cfs 13,193 cf Primary--3.26 cfs 13,193 cf Link 132L: Runoff into existing catch basins on Clark Avenue Inflow--16.95 cfs 71,251 cf Primary=16.95 cfs 71,251 cf Link 139L: Runoff towards existing wetlands to the south Inflow--30.96 cfs 130,497 cf Primary--30.96 cfs 130,497 cf I Link 141 L: Runoff towards Isolated Wetland "C"series Inflow--3.47 cfs 13,326 cf ' Primary--3.47 cfs 13,326 cf 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 I 1 1 1 1 1 1 Proposed Condition 1 Watershed Analysis 1 ' 1 � 1 . 1 1 � 1 1 1 1 1 I 1 mea w¢ v.dr�W is 7<SS 13 p�aESt� /oda tbef 7� "p ar,q. 11MS �a m�i.mm ob.anWe� ­4fthave ow+ ias mw+.a�r 166$ F]4NF9\ rel�b Mrfl \\\\\\\\\\\\\]]]111 ptlbtw 1 S L 1565 }}11 ✓� b OF., r %KBMWR! 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Subpa4 Reach _;pnO nk< Drainage Diagram for proposed-SUBMITTAL � Z k Prepared by Microsoft, Printed 8/18/2015 ' HydroCAD®9.10 sln 06611 ®2010 HydroCAD Software Solutions LLC i 1 Proposed Condition Watershed Analysis - Clark Avenue, Salem MA proposed-SUBMITTAL Prepared by Microsoft Printed 8/18/2015 HydroCAD®9.10 s/n 06611 @2010 HydroCAD Software Solutions LLC Page 2 Area Listing (all nodes) Area CN Description ' (sq-ft) (subcatchment-numbers) 418,696 70 Woods, Good, HSG C (81 S, 1115, 1365, 137S, 138S, 140S, 143S, 149S, 151S, 155S) ' 234,394 74 >75% Grass cover, Good, HSG C (80S, 81 S, 111S, 136S, 137S, 138S, 142S, 143S, 144S, 145S, 146S, 147S, 149S, 150S, 151S, 152S, 153S, 154S, 156S) 74,537 81 1/3 acre lots, 30%imp, HSG C (1385, 149S, 1555) ' 4,840 91 Rip Rap, HSG C (156S) 4,490 91 Rip rap slope, HSG C (111 S) 94,546 98 Paved parking, HSG C (80S, 81S, 144S, 145S, 146S, 1475, 149S, 150S, 1525, ' 153S, 154S) 1,125 98 Roofs, HSG C (148S) , 2,382 98 Unconnected pavement, HSG C (136S, 137S) i 37,500 98 Unconnected roofs, HSG C (80S, 111S, 136S, 137S, 138S, 142S, 143S, 144S, 145S, 146S, 147S, 150S, 151S, 152S, 153S, 1545, 156S) , 872,510 TOTAL AREA 1 i 1 Proposed Condition Watershed Analysis - Clark Avenue, Salem MA proposed-SUBMITTAL Prepared by Microsoft Printed 8/18/2015 HydroCAD®9.10 s/n 06611 @2010 HvdroCAD Software Solutions LLC Page 3 Pipe Listing (all nodes) ' Line# Node In-Invert Out-Invert Length Slope n Diam/Width Height Fill Number (feet) (feet) (feet) (ft/ft) (inches) (inches) (inches) 1 142P 128.68 119.30 268.0 0.0350 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 1 1 Proposed Condition Watershed Analysis - Clark Avenue, Salem MA proposed-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 Dyn-Star-Ind method ' Subcatchment 80S: PR-CB O+ORT Runoff Area=4,997 sf 69.68% Impervious Runoff Depth=2.16" Flow Length=205' Tc=5.0 min CN=91 Runoff=0.29 cfs 901 cf Subcatchment 81S: PR-CB O+OLT Runoff Area=8,849 sf 34.16% Impervious Runoff Depth=1.39" Flow.Length=200' Tc=5.0 min CN=81 Runoff=0.33 cfs 1,026 cf Subcatchment 111 S: EX-1R Runoff Area=190,054 sf 3.16% Impervious Runoff Depth=0.87" ' Flow Length=475' Tc=13.6 min CN=72 Runoff=3.15 cfs 13,751 cf Subcatchment 136S: EX4R Runoff Area=70,668 sf 4.80% Impervious Runoff Depth=0.87" Flow Length=420' Tc=14.2 min CN=72 Runoff=1.15 cfs 5,113 cf Subcatchment 1375: EX-2r Runoff Area=13,478 sf 11.98% Impervious Runoff Depth=1.03" ' Flow Length=280' Tc=5.0 min UI Adjusted CN=75 Runoff=0.36 cfs 1,153 cf Subcatchment 138S: EX-3R Runoff Area=195,386 sf 1.98% Impervious Runoff Depth=0.82" ' Flow Length=325' Tc=15.6 min CN=71 Runoff=2.84 cfs 13,329 cf Subcatchment 140S: EX-5(No Change) Runoff Area=49,862 sf 0.00% Impervious Runoff Depth=0.77" ' Flow Length=560' Tc=12.3 min CN=70 Runoff=0.73 cfs 3,202 cf Subcatchment 142S: PR- POND 2 Runoff Area=14,462 sf 5.19% Impervious Runoff Depth=1.03" Flow Length=85' Tc=5.0 min CN=75 Runoff=0.38 cfs 1,237 cf , Subcatchment 143S: PR-POND 1 Runoff Area=43,123 sf 9.57% Impervious Runoff Depth=1.03" Flow Length=285' Tc=5.0 min UI Adjusted CN=75 Runoff=1.14 cfs 3,690 cf Subcatchment 144S: PR-CB 1+65 RT Runoff Area=7,902 sf 58.00% Impervious Runoff Depth=1.91" Flow Length=200' Tc=5.0 min CN=88 Runoff=0.40 cfs 1,256 cf , Subcatchment 145S: PR-CB 3+50LT Runoff Area=16,522 sf 60.42% Impervious Runoff Depth=1.99" Flow Length=315' Tc=5.3 min CN=89 Runoff=0.87 cfs 2,741 cf Subcatchment 146S: PR-CB 3+50RT Runoff Area=13,314 sf 71.65% Impervious Runoff Depth=2.16" ' I Fiow Length=3'iO'- Tc=5.0 min CN=91 Runoff=0.77 cfs 2,402 cf Subcatchment 147S: PR-CB 1+65 LT Runoff Area=9,039 sf 64.32% Impervious Runoff Depth=1.99" , Flow Length=200' Tc=5.0 min CN=89 Runoff=0.48 cfs 1,499 cf Subcatchment 148S: 3/4 roof area Lot 12 Runoff Area=1,125'sf 100.00% Impervious Runoff Depth=2.87" ' Tc=5.0 min CN=98 Runoff=0.08 cfs 269 cf Subcatchment 149S: EX-RES 1r Runoff Area=94,840 sf 44.94% Impervious Runoff Depth=1.67" ' Flow Length=300' Tc=5.0 min CN=85 Runoff=4.27 cfs 13,219 cf Subcatchment 150S: PR-CB Road B Runoff Area=31,453 sf 66.98% Impervious Runoff Depth=2.08" ' Flow Length=315' Tc=6.5 min CN=90 Runoff=1.68 cfs 5,442 cf Proposed Condition Watershed Analysis - Clark Avenue, Salem MA proposed-SUBMITTAL Type 111 24-hr 2 yr Rainfall=3.10" Prepared by Microsoft Printed 8/18/2015 HydroCAD®9.10 s/n 06611 @2010 HVdroCAD Software Solutions LLC Page 5 1 Subcatchment 151S: PR-POND 3 Runoff Area=25,852 sf 1.45% Impervious Runoff Depth=0.92" Flow Length=175' Tc=5.0 min UI Adjusted CN=73 Runoff=0.60 cfs 1,981 cf Subcatchment 152S: PR-CB 9+50LT Runoff Area=14,133 sf 68.86% Impervious Runoff Depth=2:16" Flow Length=295' Tc=5.0 min CN=91 Runoff=0.82 cfs 2,549 cf Subcatchment 153S: PR-CB 10+84 Runoff Area=15,593 sf 75.41% Impervious Runoff Depth Flow Length=200' Tc=5.0 min, CN=92 Runoff=0.93 cfs 2,931 cf Subcatchment 154S: PR-CB 9+50RT Runoff Area=16,298 sf 60.58% Impervious Runoff Depth=1.99" Flow Length=330' Tc=5.0 min CN=89 Runoff=0.87 cfs 2,703 cf I Subcatchment 155S: EX-RES 2R Runoff Area=13,925 sf 26.47% Impervious Runoff Depth=1.33" Flow Length=105' Tc=5.0 min CN=80 Runoff=0.49 cfs 1,538 cf ' Subcatchmerit 156S: PR-POND 4 Runoff Area=21,635 sf 6.93% Impervious Runoff Depth=1.26" Flow Length=125' Tc=5.0 min CN=79 Runoff=0.72 cfs 2,275 cf ' Pond 78P: Proposed CULTEC 330XL Peak EIev=124.00' Storage=1,652 cf Inflow=0.69 cfs 2,196 cf Discarded=0.01 cfs 1,083 cf Secondary=0.00.cfs 0 cf Outflow--0.01 cfs 1,083 cf Pond 14213: Detention Pond 1 Peak EIev=134.01' Storage=2,178 cf Inflow=2.02 cfs 6,445 cf Discarded=0.01 cfs 617 cf Primary--0.49 cfs 5,703 cf Secondary--0.00 cfs 0 cf Outflow--0.50 cfs 6,320 cf Pond 14313: Detention Pond 2 Peak Elev=129.53' Storage=3,007 cf Inflow--2.02 cfs 6,380 cf ' Discarded=0.02 cfs 1,313 cf Primary=0.16 cfs 5,067 cf Secondary=0.00 cfs 0 cf Outflow=0.18 cfs 6,380 cf Pond 144P: Detention Pond 4 Peak Elev=119.39' Storage=2,415 cf Inflow--3.32 cfs 10,459 cf Discarded=0.01 cfs 454 cf Primary--11,211 cfs 9,946 cf Secondary--0.00 cfs 0 cf Outflow--1.22 cfs 10,400 cf Pond 15212: Detention Pond 3 Peak EIev=116.06' Storage=2,701 cf Inflow--2.28 cfs 7,423 cf Discarded=0.02 cfs 1,831 cf Primary--0.79 cfs 5,151 cf Secondary--0.00 cfs 0 cf Outflow--0.81 cfs 6,983 cf ' Link 109L: Total Surface Runoff discharging from project area Inflow=11.18 cfs 68,857 cf Primary=11.18 cfs 68,857d Link 128L: Runoff towards existing wetlands to the north Inflow--4.74 cfs 30,302 cf Primary--4.74 cfs 30,302 cf Link 130L: Runoff towards Isolated Wetland "B"series Inflow=1.15 cfs 5,113 cf Primary=1.15 cfs 5,113 cf Link 132L: Runoff towards Clark Avenue Drainage System Inflow--4.63 cfs 14,372 cf Primary--4.63 cfs 14,372 cf Link 139L: Runoff towards existing wetlands to the south Inflow--6.92 cfs 38,555 cf ' Primary--6.92 cfs 38,555 cf Link 141 L: Runoff towards Isolated Wetland "C"series Inflow--0.73 cfs 3,202 cf tPrimary--0.73 cfs 3,202 cf 1 Proposed Condition Watershed Analysis - Clark Avenue, Salem MA ' proposed-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 6 Total Runoff Area =872,510 sf Runoff Volume =84,207 cf Average Runoff Depth = 1.16" 81.90% Pervious =714,596 sf 18.10% Impervious= 157,914sf , 1 1 Proposed Condition Watershed Analysis - Clark Avenue, Salem MA proposed-SUBMITTAL Type 11124-hr 2 yr Rainfall=3.10" Prepared by Microsoft Printed 8/18/2015 HydroCAD0 9.10 s/n 06611 @2010 HydroCAD Software Solutions LLC Page 7 ' Subcatchment 8OS: PR-CB O+ORT Hydrograph 0.32 : _ 0 RunoN 0.3 ore a.. � � .... 0.28 - ....................._:---...J .............:..:...:..:..:...:..:...: : °e '24- 0.24 . . . 3.1 0.22 = ....-;-..; . RunoffArea;..4997sf 0.18 i Rtanoff VoFume' :9'01cf�- 0.16 r ' Rui off_A_6,0th=2:.1;6.`': E 0.14 . 0.12 . X flow-Lent , : o., _ 0.08 - - 0.06 i i i E i ; — ..-__.....:......:.._-..._ ..:. CN: 91-�-- ' 0.04 ' ! - -- - - 0.02 . - . , - 0 1 2 3 4 51 7 8 91011121314151617181920212223242526272829303132333'4353637383940 Time (hours) i � 1 1 Proposed Condition Watershed Analysis - Clark Avenue, Salem MA , proposed-SUBMITTAL Type ///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 Subcatchment 81S: PR-CB O+OLT Hdrorah Y 9 P 0.36 . . . , Runoff r.�0.0.34 ..t. ' oalee MI I 32 Ztyr't : n :.....................: . . . i 0.26Rain i i i t 0.26 — - . . 0.24 ;...._....--'--- - .. .. .. .. .. .. 'R 0.22 _ urioff Area: 8 X8'4.9:sf um y 0.2 0.18 — M 0.16 . _ .. _ _ __ __ __ _ _ . _ Ftow.te�'.gth; 200'. .. 0.12 0.06 : . ; , 81 .. 0.02 0 0 1 2 3 4 5 6 7 8 9 10111213l4l5l6l7l8l9202122232425262728293031323'33'43'5363'738394'0 ' Time (hours) Proposed Condition Watershed Analysis - Clark Avenue, Salem MA proposed-SUBMITTAL Type l/l 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 ! Subcatchnnent 111 S: EX-1R Hydrograph ' 0 Runoff 3AS 6i 3 pe'-111':,24�hk 2'yr ! 1 ; : Raj `0;"' Runo Area`190;0;54;sf Runoff Dept&0 8.7 Flow Length=475'; : 3. min; CN:--Y#): ! 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 Tlme (hours) ! ! ! ! Proposed Condition Watershed Analysis - Clark Avenue, Salem MA , proposed-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 Paoe 10 Subcatchment 136S: EX-4R , Hydrograph . ©RunoR 1 • • . , . . . . . . , . , . , 11-3 Ra'infa 10:"' Riunoff Area=70 Q68 sf ' Rdn:d0 Volume=5;1:1:3! d.f: Runoff Depth=0:8.7;"i ' . . . . . . . . . Flow Length=420'; :tc=1:4.2 min: C72 ' 0 1 2 3 4 5 6 7 8 9 1011 12 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 (hours) 1 1 i I I Proposed Condition Watershed Analysis - Clark Avenue, Salem MA ' proposed-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 11 Subcatchment 137S: EX-2r Hydrograph .. .0.38 . .t�� 0.36 uno 0.34 ' .. 0.32. _ 1O 0.3 Rainfa th3. r 0.26 . � .. . _ 0.26 - — '4 0.24- 0.22- .24 0.22 . 0.2 i + F + --- &:1 % - -- _ Lerlo 0.18 . : F0.16i ::De : QTc' 560::min::: OAT 0.06 '. ..:..:._:..:.............i..; _ .......... ..:.. .. �.. .. .UI::AdjusteCN :75::: 0.os ' ------- 0.04T . 0.02 01 0 1 2 3 4 5 6 7 8 910111213141516171819202122232425262728293031323334353637383940 Time (hours) 1 1 ' 1 i Proposed Condition Watershed Analysis - Clark Avenue, Salem MA ' proposed-SUBMITTAL Type ll/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 12 Subcatchnnent 138S: EX-3R Hydrograph ..` :. 3 t LL : a, ;Type. III24-h'r2yr ' nfa11=3 Ra'i :IV . .;.Ru.hoffArea=;..1.95 ; ; <s 'Runoff Voltame=13:329; cf i` : Runoff iDe0 8,2 , • Flow Le`n'gth=325'; C ........... tc °1;5.6 min: CN" 0 1 2 3 4 5 6 7 8 9 1011 12 131415 16 17 18 19 20 2122 23 24 25 26 27 28 29 30 3132 33 34 35 36 37 38 39 40 Time (hours) , 1 i Proposed Condition Watershed Analysis - Clark Avenue, Salem MA 1 proposed-SUBMITTAL Type ll/24-hr 2 yr,.Rainfall=3.10" Prepared by Microsoft Printed 8/18/2015 HydroCAD®9.10 s/n 06611 @2010 HvdroCAD Software Solutions LLC Pane 13 iSubcatchment 140S: EX-5 (No Change) Hydrograph ' 0.8 i -- --- - -- -- -- --- -- -- - - -- - -- -- -- -- ... 0.75 -- 0 RunoR ........ 0.7- ...... 11124-hr 2 yr 0.65 ---- ,..,...,.. 11"340`.!!;.. 0.6- 0.5 .6 a4 0.55 — u 0.5 _ 0.45 ' : , noff'Are , . 9862;sf-- --�--.---�--:---:--;--�---F--,_..�-- � .;--�---�--i - --�--�--�un`off-Volume]- x;20 cf'-- 0.4 ' a 0.35 0.3 — :..:...:..:..:..:..: ...:..:..: - - Flow Lenjt . . . . . . 0.25 : C . T.c.. ;12'.3..mi.n o.z . - "'1-CN- 0.15. ;. — . • -------- -- - - - , 0.05 . . . , 0 1 2 3 4 5 6 7 8 910111213141516171819202122232425262728293031323334353637383940 Time (hours) 1 t Proposed Condition Watershed Analysis - Clark Avenue, Salem MA ' proposed-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 Subcatchment 142S: PR- POND 2 . ..j.. ...;..:...:..:. ' ...y..:..;.HydrograPh 0.42 ..:.........:. , ORunoH 0.4 0.38 ............. ..i_i..i.....i..,..,._i..i. i.... : Ir 0.36 , ..�......�..i...i..i......� ------ 0.34 -- - - .. .. .. .. .. .. ... .. .. _ .. T hr 0.32 t R 0.3 r 0.28 R n ff .. . . . . ... sf u o r 0.26 .-.-."--'-'•..........:...:..:.. — R'un`off Voiutre=1-2.37 cf 0.24 � ' o.z2 >.. 0 0.2 i Runoff Depth=10.3!rr : . , r: 0.18 •..........:.... i „�'.. - - — 0.14 ' , is ti C Tc 0.12 � . . ........ . 0.08 0.06 . - 0.04 ..:..1..i..j.. ;......:..i - - - ------------------ ....... OM - - - o.oz 0. 0 1 2 3 4 5 6 7 8 910111213141516171819202,12223242526272829303,323334353637383'9"'4"0 Time (hours) 1 1 1 Proposed Condition Watershed Analysis - Clark Avenue, Salem MA proposed-SUBMITTAL Type ll/24-hr 2 yr, Rainfall=3.10" Prepared by Microsoft Printed 8/18/2015 HydroCAD®9.10 s/n 06611 ©2010 HvdroCAD Software Solutions LLC Page 15 Subcatchment 143S: PR-POND 1 Hydrograph F13 Runoff I ru a. i - hr-------------- - - --- - ' . - 'Rainfl1=310" ' Ru noffArea=43;123; sf ,p Runoff Volume"1690 df TiI I F 0 Rt noff D60th=1 :03;nf F.0 L6,rI9th=285" Tc=5.0 min: UIQdjusted C,N.=75' i 0 1 2 3 4 5 6 7 8 9 1011 12 13141516 171819 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 Time (hours) 1 r r Proposed Condition Watershed Analysis - Clark Avenue, Salem MA ' proposed-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 16 ' Subcatchment 144S: PR-CB 1+65 RT ..: :y rogra:p _;-- j. . .. . i . .i. .. .i... .. ... : Rff0i _ . . . { �-- --{-- -.-l..i..:. - ---F-- O .44 -.,..-`-'--{---F--i-- ..'_-i- 0.42 . .::. oeo a.r..:..:. _ - ' hr 0.36 1 ,. T. � HF24i 2 :r` . , . . , 0.34 ai 0.32 . .:................................:... ...... ��� �.. r 90 sf 0.3 .....:.........:. .. I--�-- -- _--F-- --a-- -_- - R - ,c�-ff- - - -F-' 0.26 i- -- -- --i-- -- - ....... - --- - -- - -- .� 0.26 ;_.l..l_.... ...; —1:T2 `--'--'-' � -- Ru'n: :Voluti�e.°.- X5;6"-cf. .. .~". 0.24 �; �:. ::�::�:::i ::f:: :�; .. ..j.. . — ... 0.22 ;- : + ; . ;..:}runoff=Dep#h=1 :9.'1;" u: 0.2 - - --- j--T- -'— i--T-- -- -- --CI- - ----- -- -- -- --- - 0.18. row-Lngth=QUO" - 0.16 ., ...... ' 0.14 . ,. .. TC+--"5'+O. LN 0.1 _ - 0.08 0.06 t 0.02 j j . : i . j . . 0 1 2 3 4 5 6 7 8 9 ,01112 13141516171819202122 23242526272829303132 3334353637383940 , Time (hours) r r ' Proposed Condition Watershed Analysis - Clark Avenue, Salem MA proposed-SUBMITTAL Type /11 24-hr 2 yr Rainfall=3.10" ' Prepared by Microsoft Printed 8/18/2015 HydroCAD®9.10 s/n 06611 @2010 HvdroCAD Software Solutions LLC Page 17 ' Subcatchment 145S: PR-CB 3+50LT Hydrograph 0.95 ;.. . ..:...'... .. - -- - -- - - - -- --------------�-----;...- .............:...:............... ..._._+..f.. 0.85 ' ' ' . 0 Runoff -:_:...:..:_......:...�..1- : . , J :..t ' 0.75- 0.7- .. .75 . ..;.__..:..:..:..:.... .... _ 11=3 0.7 , rf 0.65 ' .. ..j... .. .. ..... .. .. . Runoff ARea-16 522,sf':: 0.6 -- .-.- -- -- ----�- s -- - -f- -* �� -1Rff-VO1U4n 0.55 '-- - - - .. 0 0.45 i=1:99;.. 0.4 _ — n,c -ow- e` : 315'x ' ; - - - 0.3 _ . .;.. • .;...y..;..;.. .;..;.. 0.25 F :c ;53 min; 1 = 0.15 0.1 0.05 . � _71 0 1 2 3 4 5 6 7 8 9 1011 1'2­1'3"'1"4- 171819 20 21 22 23 24 25 26 27 28 2930 3132 33 34 35 36 37 38 39 40 Time (hours) 1 t t Proposed Condition'Watershed Analysis - Clark Avenue, Salem MA ' proposed-SUBMITTAL Type N 24-hr 2 yr Rainfall=3.10" t Prepared by Microsoft Printed 8/18/2015 HydroCAD&9.10 s/n 06611 @2010 HydroCAD Software Solutions LLC Paoe 18 Subcatchnnent 146S: PR-CB 3+50RT , Hydrograph 0.85 ..j.. ..:.. I T - 0.8 'o.n.m. .. Runoff -------------- .0.75 �, .. .. i. ..i T,ype . 1r..2yr. .. .0.7- 0.65. .70.65 ' � Ranfa 0.6 -- '- - - -- -- --- -- -- -- _ -- - - -- : -'. . Ruts �Ar-ea 13 0.5 :.. ..;_ 'unoff Volume=21!4 s€ 0.55 --{--, ,---i--;--->-- - --+-- ..;..�..;..� . j......, j..• -- ... cf. _ .. . ; 0.45 u a 0.4 . . : . e 't 16 0 i p LL . ' 0.35 : : : , -. gth 310-r; 0.3 . ' . . . .. _ . . , . . . . , , , . . . , . , . 0.25 0 m o.z . CN. 0 .15 .. .. .. . -i 0.1 i 0.05 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 (hours) 1 ' Proposed Condition Watershed Analysis - Clark Avenue, Salem MA proposed-SUBMITTAL Type 11/24-hr 2 yr Rainfall=3.10" Prepared by Microsoft Printed 8/18/2015 HydroCAD®9.10 sin 06611 ©2010 HvdroCAD Software Solutions LLC Page 19 tSubcatchment 147S: PR-CB 1+65 LT Hydrograph ..i...?..i .:..: 0.5 ! i i ..:.gym... i ! i o iiii ! ii � no i.. ...:..:...:'..i.. 0.45 i i I i.. ...:..:..: .;...Tyke; IIF24-hr..2. yr . 0.4-. ��Rainfa ..;.. �; i.. ;Runoff Area 9 03;9 sf ( ff Volume-"1,,499 cf 42 0.3 ; 0 0.25 : 0.2 ' ' ; ; ' ; ngth- - � -�--' ;--Flow to : 200': ' = - 0.15 - -- -- -- - _ - 5�-0-min'- 1 01CN-89 -- 0.05f �Y, 0 , 2 3 4 5 6 7 8 910111213141516171819202122232425262728293031323334353637383940 Time (hours) 1 1 1 I t I 1 Proposed Condition Watershed Analysis - Clark Avenue, Salem MA proposed-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 20 Subcatchment 148S: 3/4 roof area Lot 12 ' Hydrograph 0.085 : oe - ............ - - - -i 0.0.06 a. 0.075 : : e:alla24:='hr 2. 0.07 T " fal .YP . F.-* �•� 0.065 ...............:. ..:.. — .. .. .. .. .. -'R ' 0.66 - ..;..r — .. _ _t.. .. .. 0.055 , ._._._................: _ __ --------- o.65 _ _ _ _ r ff�Ar 1�' 125 -� 0,05 -> - •u o a. 0.�5 . �2unoff Vo�t--me- X69 - o.� — 0.035 ; Hoff-Dept �:87 . . 0.03 ,j✓ .{.. .. . .._!_.i..;_1_F..;_..y__:_-_T,\i— OFm ,ii_. 5. i 0.025 ..,.._........,_.�_.--r__.__. _ _ _ _ . 0.02 .........:..:.........._....:_... , 1.�...: : — 0.015 ' 0.01 0.005 0 0 1 2 3 4 5 6 7 8 9 1011 121314151617 1819202122232425262728293031 3233M3536373839,W Time (hours) 1 1 Proposed Condition Watershed Analysis - Clark Avenue, Salem MA proposed-SUBMITTAL Type ///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 21 ' Subcatchment 149S: EX-RES 1r Hydrograph ■ 11:24 -ht-2: : t t . . 'TYp 4e`-Ii -- 1 Rainfall=3:10: i.. R lu n off;Area;. 9.4 840:sf,'-.- 3 :RtaOoff Vo!Itame=13;21:9: cf . h"1 :67" . ' 2 FIow�Len'gt =300" is h: :Tc=5.0 min' . i . 85 �� 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 Tlme (hours) ' 1 1 1 Proposed Condition Watershed Analysis - Clark Avenue, Salem MA , proposed-SUBMITTAL Type ///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 22 Subcatchment 150S: PR-CB Road B , Hydrograph O Runoff n:ee a. TyPe, Ill;24 he 2 yr R41nfa11=310 bho' 'Are'a=31 ;453: 'f - :4412; ; Runoff Depth"20.8,'" F104166 !th=315': Tc 6 'rrii! CNI=90: 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 (hours) ' Proposed Condition,Watershed Analysis - Clark Avenue, Salem MA proposed-SUBMITTAL Type ll/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 Pace 23 ' Subcatchment 151S: PR-POND 3 Hydrograph 0.65 ; O Runaft 0.6 L. i.. 0.55 ' 1 _ 0.5 ; � of 3:10 r .. a_2 0.45 _ :Runoff Ar .. 0.4 — �—' 0.36 ..Ruoff Volume` 1 X9'8!1-�-cf' .a - . : pth - 0.25 ngth • . , Tc ''5:0 mi` ' 0.,5 T i. 0.05 . 0 1 2 3 4 5 6 7 8 9 1011 12 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 nme (hours) t ,1 1 1 Proposed Condition Watershed Analysis - Clark Avenue, Salem MA ' proposed-SUBMITTAL Type ll/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 24 Subcatchment 152S: PR-CB 9+50LT ' Hydrograph 0.85 ..;:.:...L.l.�...j..;...;..;.. o:BZea J'..L..:..;..;... ...L... j... ... .. . ... ... 1........ O Runoff jj . ;..;... 0.75- 0.7- 0.65 .75 hr :Type; 111;24-ht 6.7 -�--=-=--�-- - - - -- -- - - 0.65 ff'A - 4 F� f' 0.6 '. -- - -' -- -- ...... - -- - ------------------- 0.55 - -- -- -- --- -- -- -- -- - - - --- -- : : 6.55 — Rtario : 'rea' 1�: 3:3`s R` 'noff Volume=2 X5'41 cf u 0.5 6.45 — :..;.. - o i- - 0.4 6.35 . ..:.. ...:..:...:..:.. ... �..,. ;... ..i.. ..' , Flow Len:gth=295'; 0.3 6.25 Tc=°5:O mini C 0.2 p 0.15 . .....�...............___._..___..f - _ __ __ ___ __ __ 0.1 , .....,...i..i...c..i . 0.05 ' � � .� _ 0 1 2 3 4 5 6 7 8 4 10111213141516171819202122232"4 A 26 27 2'8'2"9 30 3,1 32 33 34 35 36 3,7 38 3,9-'4',0 Time (hours) 1 1 Proposed Condition Watershed Analysis - Clark Avenue, Salem MA proposed-SUBMITTAL Type l//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 25 Subcatchment 153S: PR-CB 10+84 Hydrograph .. -------------- 1 ! j ! l7 Runoff e. 'Ty';pe (11;24-hl 2':yr Rainfall=3:10 RuloffArea=15;59;3 sf 1 Rurjoff Volume=2;93.1. cf Runoff l7epth=2:26 LL Flow Le.6 'th=200': ' rC5".0 min; 0 1 2 3 4 5 6 7 8 9 1011 1213141516 171819 20 21 22 23 24 25 26 27 282930 31 32 33 343536 3'7"'3'8"'39 40 1 Time (howl) 1 � 1 1 ' 1 1 1 1 1 Proposed Condition Watershed Analysis - Clark Avenue, Salem MA proposed-SUBMITTAL Type ///24-hr 2 yr Rainfall=3.10" 1 Prepared by Microsoft Printed 8/18/2015 HydroCAD®9.10 s/n 06611 ©2010 HydroCAD Software Solutions LLC Page 26 Subcatchment 154S: PR-CB 9+50RT 1 Hydrograph - - - - .................... . . 0.95 -'- ..........:......:.. .. O Rurroft o.eza.' 0.65 . .. .. ._ .. .. . - pe -III- 24-hr-2 -y' .. - . ..0.8 -- -- -- -- -- -- -- -- -- -- - -- .-- ..:..:..:...:..:..:.. .. ... .. ... .. ..: 0.75- Rainfall-x;1:0. 0.65 ':.. ..i.. .. ...: t16-296-9f--- ; Runoff'Area os + - — o.5s . . 1 --- - -- - -- . ; ; ; :Ru n`off.-Volume: 2�7:03 -Cf-- 0.5 ::- t h=1:99?� :. 0 0.4s r : _ _.r'.- 0.4 ..'-T.. '- ..�:- - Lino T : .:_eR -I- =-- -- 0.35 . . . , . , , . , ��..: low Length---3 0.3 — r..:..:...: .:........ min: o.2s _ c 0.2 : — �,: CN;: :;8.9: OJ 0.05 . _ 0 1 2 3 4 5 6 7 8 9 1011 12 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 (hours) 1 1 1 I 1 1 1 1 1 Proposed Condition Watershed Analysis - Clark Avenue, Salem MA proposed-SUBMITTAL Type l/l 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 27 Subcatchment 155S: EX-RES 2R Hydrograph i , 0.55 0 Runoff 0.5- h 1..1..'--------- -- --- -- -- - - -- - -- -- -- ii .-- --�- ;--�=- ---TYpe TIL;24-.1a'r 2 i yr- 0.45 i t . ; • ' =_ . ; -= ' II=3:10". .. 0.4- of -........ - ... . 'IZuroffArea=1� 3;92.5;sf� ;. - 0.35 = _ Vo�u:rne' 1538' ef�-- 3 LL 0.25- '* = Runoff Depth=1:33; ; ; ; ' 0.2 i i i i i aTgth- �• .;..,..�_,-,._......,._i.. .- ;_Flow iLe' ; 105'.,.. 0.15 , C. N :c .50-min: .... =80 • 0.1 t 0.05 0 1 2 3 4 5 6 7 8 9 10111213141516171819202122232425262728293031323334353637383940 1 Time (houm) I . . Proposed Condition Watershed Analysis - Clark Avenue, Salem MA proposed-SUBMITTAL Type /// 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 Pace 28 Subcatchment 156S: PR-POND 4 Hydrograph o.e ©w,noo 0.75 ..i...f...'.y...�.. ..;...i..i..-- --r1..- ..F..{.- ..i--�..•o.nd. ;..;.... --{-- ;. , ..'..; 0.7 --F-- : : yr; 0.65 113:1:0:-'' -. '0.6 - Rainfa 0.55 ; : ;_.;.. .. -: unoff Area=21.,6;3'Ssf .. 0.5 t i { 2;2 -- 0.45 . : Runoff-Volum�e- X75 cf! 0 0.4 .. ... .. ..<.. ..' Runoff.Depth=1:2.6". .. u 0.35 i ! i 0.3 : Flow Length=12 . . . . _ 0.26 ..:..:................:...:..:.. . qtr - - - - . . . . . . . . . . �; c �S.Q.min .. 0.2. 0.15 CN'_79 ....._.............. - 0.1 0.05 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 (hours) ' I I 1 1 Proposed Condition Watershed Analysis - Clark Avenue, Salem MA proposed-SUBMITTAL Type 111 24-hr 2 yr Rainfall=3.10" 1 Prepared by Microsoft Printed 8/18/2015 HydroCADO 9.10 s/n 06611 ©2010 HvdroCAD Software Solutions LLC Page 29 1 Pond 78P: Proposed CULTEC 330XL (Infiltration System #1) - Chamber Wizard Field A Chamber Model =Cultec R-330XL 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 52.0" Wide + 6.0" Spacing = 58.0" C-C 8 Chambers/Row x 7.00' Long = 56.00' + 12.0" End Stone x 2 = 58.00' Base Length ' 5 Rows x 52.0" Wide + 6.0"Spacing x 4 + 12.0" Side Stone x 2 = 25.67' Base Width 6.0" Base + 30.5" Chamber Height + 6.0" Cover = 3.54' Field Height 1 40 Chambers x 52.2 cf= 2,086.3 cf Chamber Storage 5,272.4 cf Field - 2,086.3 cf Chambers = 3,186.1 cf Stone x 40.0% Voids = 1,274.4 cf Stone Storage ' Stone + Chamber Storage = 3,360.7 cf= 0.077 of 40 Chambers ' 195.3 cy Field 118.0 cy Stone { pp t t P �f•r ' t 3 f' i101i. t " t t. N« ' 4 1 bb G i 1 1 Proposed Condition Watershed Analysis - Clark Avenue, Salem MA proposed-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 30 Pond 78P: Proposed CULTEC 330XL (Infiltration System #1) ' Hydrograph - - - ------------------ - Li --- ---- ...... --- ------ -- - -- - a=1 w1ow 0. Mai e bed 0.75 : .% ..... ......... .:...... ow -Are: . - :4--97-.11--'sf---- ®saw Mary0.65 ..-- v_0.55 -- . — : .._. ---- ---� . to rage 0.45 i0.35 . .: ----�-----I----...----� ---�----�----•-----�-.-.-•---.-•-----...---------•- - -+-- -0.3 0.25 .. : _ ---------------- ----- _ ___ _____ __ 0.15 am a. 0.1 0 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 Time (hours) 1 - 1 1 ! 1 ! i 1 ' Proposed Condition Watershed Analysis - Clark Avenue, Salem MA I proposed-SUBMITTAL Type 11124-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 31 Pond 142P: Detention Pond 1 Hydrograph 13 inflow i --- -- ---- --- - --- --- - ------- - - ;---"{- -- z.oz e.- - .' - Inflow Area 6 ,064 SSI ®Dista Discarded O Primary 0 Secondary 2 Peak Elev=134.01 ' i e=2 2- Sto' rag !c i • S0.49 ds o.aa m i 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 I ' Time (hours) I I i 1 1 Proposed Condition Watershed Analysis - Clark Avenue, Salem MA i proposed-SUBMITTAL Type ///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 Paae.32 Pond 143P: Detention Pond 2 ' Hydrograph Inflow i zoz e: ' 1 � 0 Primaryed Inflow Are a ,4 4,2"08 �sf ©Secondary 2 Perak ElreV 129.53, ' Is i 't o . ag e' 3,00:7 �c .2 0.00 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 Time (hours) i i ' Proposed Condition Watershed Analysis - Clark Avenue, Salem MA proposed-SUBMITTAL Type 11l 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 33 Pond 144P: Detention Pond 4 Hydrograph 13 In00w . .. A. - a=6 i �.��. uwo�+ �nfJow-Are 7;659 s Discarded f... 0 El Primary Secondary Pe.�ak. Elev119.39! 3 i --.-S-10! e= rag 2;415 cf- 2 . 0 Jjjliiiiljjjjjj -------------------- LL '-151 qsi 1 0.0014 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 ' T1me (hours) i Proposed Condition Watershed Analysis - Clark Avenue, Salem MA ' proposed-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 34 Pond 152P: Detention Pond 3 ' Hydrograph 13 Inflow , . j .._.�......_..:.....�.:..aEl Outflow Discarded a� 7,305.. oPrimary .1hfowAre Secondary Peak El;ev=116.06 ' ' 27 I Storage=2,701 cf ' e:erLz _e LL .1 ona III La' O.00 Lev 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 Time (hours) ' 1 1 Proposed Condition Watershed Analysis - Clark Avenue, Salem MA proposed-SUBMITTAL Type ///24-hr 2 yr Rainfal1=3.10" Prepared by Microsoft 015 Printed 8/18/2 HydroCAD®9.10 s/n 06611 ©2010 HydroCAD Software Solutions LLC P8/2 35 ' -Link 109L: Total Surface Runoff discharging from project area Hydrograph re 0 i..i. ..i..d-i..i ' 12 i.-i.. .< _ O Primary ij i a�. nflow -Are 98:0 a# - - - -- -- -- - --------- -- rr . , { . r LL _ .......... .. __ _ • i y i i I I tT - - __ - _ __ _ r r • ' 3' r r r 0 , 2 3 4 5 6-7, 8 910111213141516171819202122232425262728293031323334353637383940 Tlme (hours) 1 Proposed Condition Watershed Analysis - Clark Avenue, Salem MA ' proposed-SUBMITTAL Type 11124-hr 2 yr Rainfall=3.10" ' Prepared by Microsoft Printed 8/18/2015 HydroCAD@ 9.10s/n 06611 ©2010 HydroCAD Software Solutions LLC Page 36 Link 128L: Runoff towards existing wetlands to the north ' Hydrograph . ... . .:..:. n ow ©Primary 1 5- flow; Area=3151936 ' f • • -- - - -- 4 g v4 C 3- 2- . . . . . . . . . . . . .2 1 O 0 1 2 3 4 5 6 7 8 9 10111213141516171819202122232425262728293031323334353637383940 Time (hours) ' 1 1 1 it Proposed Condition Watershed Analysis - Clark Avenue, Salem MA 1 proposed-SUBMITTAL Type 111 24-hr 2 yr Rainfall=3.10" Prepared by Microsoft Printed 8/18/201,5 HydroCAD®9.10 s/n 06611 ©2010 HydroCAD Software Solutions LLC Page 37 1 Link 130L: Runoff towards Isolated Wetland "B" series Hydrograph 1 ®InOow 1'15 a. O Primary . .1.15 i� • -7 1 3 � 1 LL 1 1 a 0 1 2 3 4 5 6 7 8 9 1011 12 1314 15 1617 18192021222324 25 2627 282930 313233 34 3536 37 3839 40 Time (hours) . 1 I 1 1 Proposed Condition Watershed Analysis - Clark Avenue, Salem MA proposed-SUBMITTAL Type 11124-hr 2 yr Rainfall=3.10" t Prepared by Microsoft Printed 8/18/2015 HydroCAD®9.10 s/n 06611 @2010 HydroCAD Software Solutions LLC Page 38 Link 132L: Runoff towards Clark Avenue Drainage System ' Hydrograph ; 57 0 Primary : a=1 now: `re a-,- 4 3 • • • -- 2- -- i 1 i a 0 1 2 3 4 5 6 7 8 9 101l12l3l4l5l6i7l8l9202122232425262728293031323334353637383940 Time (hours) ' I I I 1 I 1 Proposed Condition Watershed Analysis - Clark Avenue, Salem MA i ' proposed-SUBMITTAL Type l/l 24-hr 2 yr Rainfall=3.10" Prepared by Microsoft Printed 8/18/2015 HydroCAD®9.10 s/n 06611 @2010 HvdroCAD Software Solutions LLC Page 39 I Link 139L: Runoff towards existing wetlands to the south Hydrograph . I i o�m -4:..:..: : nfl-o-w -Ari 3- j-044. sf- --- 6 -- P L • 4. 1 3 . . . . . . j. i. � - ! -- -- --- -- - --- ------------------ -- -- -- - — -- ii ' 1 0 1 23 4 5 6 7 8 9 10111213141516171819202122232425262728293031323334353637383940 Time (hours) I 1 1 r Proposed Condition Watershed Analysis - Clark Avenue, Salem MA , proposed-SUBMITTAL Type 11124-hr 2 yr Rainfall=3.10" ' Prepared by Microsoft Printed 8/18/2015 HydroCAD®9.10 s/n 06611 ©2010 HydroCAD Software Solutions LLC Paoe 40 Link 141 L: Runoff towards Isolated Wetland "C" series , Hydrrlgraph i..:..L.ii Inflow ... :.........i..;.,.i..i i0 Primary ;.-{..{..- ... .. {_ { .......... w � ` s{ ' f. �__ 0.75 I. -A .a49 $ 0.7 0.65 . . 0.6 ...... . 0.55 ; 0.5 . i 45 0. II I I I II o. 3 0.4 ._{...-.. -- {--{ 0 CL 0.35 0.3 ..- - ...........r- - - -- -- - - --------- ------ 0.2 5 0.2 i`; - - - - 0.15 i i t 0.05 ' 0 1 2 3 4 5 6 7 8 910111213141516171819202122232425262728293031323334353637383940 Time (hours) ' 1 Proposed Condition Watershed Analysis - Clark Avenue, Salem MA ' proposed-SUBMITTAL Type 111 24-hr 10 yr Rainfall=4.50" Prepared by Microsoft Printed 8/18/2015 HydroCADO 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 80S: PR-CB O+ORT Runoff Area=4,997 sf 69.68% Impervious Runoff Depth=3.50" Flow Length=205' Tc=5.0 min CN=91 Runoff=0.46 cfs 1,457 cf ' Subcatchment 81S: PR-CB O+OLT Runoff Area=8,849 sf 34.16% Impervious Runoff Depth=2.55" r Flow Length=200' Tc=5.0 min CN=81 Runoff=0.61 cfs 1,879 cf ' Subcatchment 111 S: EX-1R RunoffArea=190,054 sf 3.16% Impervious Runoff Depth=1.82" Flow Length=475' Tc=13.6 min CN=72 Runoff=7.10 cfs 28,831 cf I ' Subcatchment 136S: EX-4R Runoff Area=70,668 sf 4.80% Impervious Runoff Depth=1.82" Flow Length=420' Tc=14.2 min CN=72 Runoff=2.60 cfs 10,720 cf Subcatchment 137S: EX-2r Runoff Area=13,478 sf 11.98% Impervious Runoff Depth=2.05" Flow Length=280' Tc=5.0 min UI Adjusted CN=75 Runoff=0.74 cfs 2,303 cf Subcatchment 138S: EX-3R Runoff Area=195,386 sf 1.98.% Impervious Runoff Depth=1.75" Flow Length=325' Tc=15.6 min CN=71 Runoff=6.59 cfs 28,435 cf Subcatchment 14OS: EX-5(No Change) Runoff Area=49,862 sf 0.00% Impervious Runoff Depth=1.67" ' Flow Length=560' Tc=12.3 min CN=70 Runoff=1.74 cfs 6,955 cf Subcatchment 142S: PR- POND 2 Runoff Area=14,462 sf 5.19%Impervious Runoff Depth=2.05" Flow Length=85' Tc=5.0 min CN=75 Runoff=0.79 cfs 2,471 cf Subcatchment 143S: PR-POND 1 Runoff Area=43,123 sf 9.57% Impervious Runoff Depth=2.05" Flow Length=285' Tc=5.0 min UI Adjusted CN=75 Runoff=2.37 cfs 7,368 cf Subcatchment 144S: PR-CB 1+65 RT Runoff Area=7,902 sf 58.00% Impervious Runoff Depth=3.20" Flow Length=200' Tc=5.0 min CN=88 Runoff=0.67 cfs 2,105 cf ' Subcatchment 145S: PR-CB 3+50LT Runoff Area=16,522 sf 60.42% Impervious Runoff Depth=3 .30" Flow Length=315' Tc=5.3 min CN=89 Runoff=1.42 cfs 4,537 cf Subcatchment 146S: PR-CB 3+50RT Runoff Area=13,314 sf 71.65% Impervious Runoff Depth=3.50" •-F7iuw Length=310' Tc=5.0 min CN=91 Runo =1.22 cfs 3,881 cf ' Subcatchment 147S: PR-CB 1+65 LT Runoff Area=9,039 sf 64.32% Impervious Runoff Depth=3.30" Flow Length=200' Tc=5.0 min CN=89 Runoff=0.79 cfs 2,482 cf ' Subcatchment 148S: 3/4 roof area Lot 12 Runoff Area=1,125 sf 100.00% Impervious Runoff Depth=4.26 Tc=5.0 min CN=98 Runoff=0.11 cfs 400 cf Subcatchment 149S: EX-RES 1r Runoff Area=94,840 sf 44.94% Impervious Runoff Depth=2.91" ' Flow Length=300' Tc=5.0 min CN=85 Runoff=7.42 cfs 22,992 cf Subcatchment 15OS: PR-CB Road B Runoff Area=31,453 sf 66.98% Impervious Runoff Depth=3.40" ' ' Flow Length=315' Tc=6.5 min CN=90 Runoff=2.70 cfs 8,901 cf F 1 Proposed Condition Watershed Analysis - Clark Avenue, Salem MA proposed-SUBMITTAL Type ///24-hr 10 yr Rainfall=4.50" Prepared by Microsoft Printed 8/18/2015 HydroCADO 9.10 s/n 06611 @2010 HydroCAD Software Solutions LLC Pape 2 Subcatchment 151S: PR-POND 3 Runoff Area=25,852 sf 1.45% Impervious Runoff Depth=1.90. ' Flow Length=175' Tc=5.0 min UI Adjusted CN=73 Runoff=1.30 cfs 4,084 cf Subcatchment 152S: PR-CB 9+50LT Runoff Area=14,133 sf 68.86% Impervious Runoff Depth=3.50" ' Flow Length=295' Tc=5.0 min CN=91 Runoff=1.29 cfs 4,120 cf Subcatchment 153S: PR-CB 10+84 Runoff Area=15,593 sf 75.41% Impervious Runoff Depth=3.60" ' Flow Length=200' Tc=5.0 min CN=92 Runoff=1.45 cfs 4,681 cf Subcatchment 154S: PR-CB 9+50RT Runoff Area=16,298 sf 60.58% Impervious Runoff Depth=3.30" , Flow Length=330' Tc=5.0 min CN=89 Runoff=1.42 cfs 4,475 cf Subcatchment 155S: EX-RES 2R Runoff Area=13,925 sf 26.47% Impervious Runoff Depth=2.46" ' Flow Length=105' Tc=5.0 min CN=80 Runoff=0.92 cfs 2,856 cf Subcatchment 156S: PR-POND 4 Runoff Area=21,635 sf 6.93% Impervious Runoff Depth=2.38" ' Flow Length=125' Tc=5.0 min CN=79 Runoff=1.38 cfs 4,285 cf Pond 78P: Proposed CULTEC 330XL Peak Elev=125.56' Storage=3,136 cf Inflow--1.18 cfs 3,735 cf Discarded=0.01 cfs 1,133 cf Secondary--0.00 cfs 0 cf Outflow--0.01 cfs 1,133 cf ' Pond 142P: Detention Pond 1 Peak Elev=134.68' Storage=3,374 cf Inflow--3.81 cfs 11,955 cf. Discarded=0.01 cfs 678 cf Primary=1.70 cfs 11,148 cf Secondary--0.00 cfs 0 cf Outflow=1.72 cfs 11,826 cf ' Pond 143P: Detention Pond 2 Peak EIev=130.28' Storage=5,624 cf Inflow--3.42 cfs 10,889 cf Discarded=0.02 cfs 1,757 of Primary--0.21 cfs 9,132 cf Secondary--0.00 cfs 0 cf Outflow--0.24 cfs 10,889 cf Pond 144P: Detention Pond 4 Peak EIev=120.42' Storage=4,677 cf Inflow--5.55 cfs 17,560 cf Discarded=0.02 cfs 521 cf Primary--1.54 cfs 16,979 cf Secondary--0.00 cfs 0 of Outflow--1.56 cfs 17,500 of Pond 152P: Detention Pond 3 Peak EIev=116.60' Storage=4,401 cf Inflow--3.99 cfs 12,984 cf Discarded=0.02 cfs 1,940 cf Primary--1.48 cfs 10,577 cf Secondary--0.00 cfs 0 cf Outflow--1.50 cfs 12,517 cf Link 109L: Total Surface Runoff discharging from project area Inflow--23.40 cfs 133,253 cf ' Primary--23.40 cfs 133,253 of Link 128L: Runoff towards existing wetlands to the north Inflow--9.28 cfs 57,798 cf Primary=9.28 cfs 57,798 cf Link 130L: Runoff towards Isolated Wetland "B" series Inflow--2.60 cfs 10,720 cf ' Primary--2.60 cfs 10,720 cf Link 132L: Runoff towards Clark Avenue Drainage System Inflow--8.11 cfs 25,295 cf , Primary=8.11 cfs 25,295 cf Link 139L: Runoff towards existing wetlands to the south Inflow-14.60 cfs 75,455 cf Primary--14.60 cfs 75,455 cf ' Link 141 L: Runoff towards Isolated Wetland "C" series Inflow-1.74 cfs 6,955 cf Primary--1.74 cfs 6,955 cf , ' Proposed Condition Watershed Analysis - Clark Avenue, Salem MA proposed-SUBMITTAL Type ///24-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 3 Total Runoff Area=872,510 sf Runoff Volume= 160,216 cf.. Average Runoff Depth =2.20".. 81.90% Pervious= 714,596 sf 18.10% Impervious = 157,914 sf 1 1 1 1 1 1 - Proposed Condition Watershed Analysis - Clark Avenue, Salem MA ' proposed-SUBMITTAL Type 111 24-hr 100 yr Rainfall=6.50" ' 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 Dyn-Stor-Ind method Subcatchment 80S: PR-CB O+ORT Runoff Area=4,997 sf 69.68% Impervious Runoff Depth=5.45" ' Flow Length=205' Tc=5.0 min CN=91 Runoff=0.69 cfs 2,268 cf Subcatchment 81 S: PR-CB O+OLT Runoff Area=8,849 sf 34.16% Impervious Runoff Depth=4.34" ' Flow Length=200' Tc=5.0 min CN=81 Runoff=1.03 cfs 3,202 cf Subcatchment 111 S: EX-1R Runoff Area=190,054 sf 3.16% Impervious Runoff Depth=3.41" ' Flow Length=475' Tc=13.6 min CN=72 Runoff=13.56 cfs 53,957 cf Subcatchment 136S: EX-4R Runoff Area=70,668 sf 4.80% Impervious Runoff Depth=3.41" ' Flow Length=420' Tc=14.2 min CN=72 Runoff=4.97 cfs 20,063 cf Subcatchment 137S: EX-2r Runoff Area=13,478 sf 11.98% Impervious Runoff Depth=3.71" ' Flow Length=280' Tc=5.0 min UI Adjusted CN=75 Runoff=1.35 cfs 4,169 cf Subcatchment 138S: EX-311 Runoff Area=195,386 sf 1.98% Impervious Runoff Depth=3.31" Flow Length=325' Tc=15.6 min CN=71 Runoff=12.88 cfs 53,839 cf ' Subcatchment 14OS: EX-5(No Change) Runoff Area=49,862 sf 0.00% Impervious Runoff Depth=3.21" Flow Length=560' Tc=12.3 min CN=70 Runoff=3.47 cfs 13,326 cf ' Subcatchment 142S: PR- POND 2 Runoff Area=14,462 sf 5.19% Impervious Runoff Depth=3.71" Flow Length=85' Tc=5.0 min CN=75 Runoff=1.45 cfs 4,474 cf ' Subcatchment 143S: PR-POND 1 Runoff Area=43,123 sf 9.57% Impervious Runoff Depth=3.71" Flow Length=285' Tc=5.0 min UI Adjusted CN=75 Runoff=4.31 cfs 13,340 cf Subcatchment 144S: PR-CB 1+65 RT Runoff Area=7,902 sf 58.00% Impervious Runoff Depth=5.11" ' Flow Length=200' Tc=5.0 min CN=88 Runoff=1.05 cfs 3,364 cf Subcatchment 145S: PR-CB 3+50LT Runoff Area=16,522 sf 60.42% Impervious Runoff Depth=5.22" t Flow Length=315' Tc=5.3 min CN=89 Runoff=2.20 cfs 7,188 of Subcatchment 146S: PR-CB 3+50RT Runoff Area=13,314 sf 71.65% Impervious Runoff Depth=5.45" ' - -Flow-Length=310' Tc=5.0 min CN=91 Runu =1.65 cfs 6,044 cf Subcatchment 147S: PR-CB 1+65 LT Runoff Area=9,039 sf 64.32% Impervious Runoff Depth=5.22" ' Flow Length=200' Tc=5.0 min CN=89 Runoff=1.22 cfs 3,933 cf Subcatchment 148S:314 roof area Lot 12 Runoff Area=1,125 sf 100.00% Impervious Runoff Depth=6.26" Tc=5.0 min CN=98 Runoff=0.17 cfs 587 cf Subcatchment 149S: EX-RES 1 r Runoff Area=94,840 sf 44.94% Impervious Runoff Depth=4.78", Fldw Length=300' Tc=5.0 min CN=85 Runoff=11.97 cfs 37,746 cf ' Subcatchment 150S: PR-CB Road B Runoff Area=31,453 sf 66.98% Impervious Runoff Depth=5.33" Flow Length=315' Tc=6.5 min CN=90 Runoff=4.14 cfs 13,980 cf , ' Proposed Condition Watershed Analysis - Clark Avenue, Salem MA ' proposed-SUBMITTAL Type 111 24-hr 100 yr Rainfall=6.50" Prepared by Microsoft Printed 8/18/2015 HydroCAD®9.10 s/n 06611 @2010 HvdroCAD Software Solutions LLC Paae 5 Subcatchment 151 S: PR-POND 3 Runoff Area=25,852 sf 1.45% Impervious Runoff Depth=3:51" Flow Length=175' Tc=5.0 min UI Adjusted CN=73 Runoff=2.44 cfs 7,557 cf Subcatchment 152S: PR-CB 9+50LT Runoff Area=14,133 sf 68.86% Impervious Runoff Depth=5.45" Flow Length=295' Tc=5.0 min CN=91 Runoff=1.96 cfs 6,416 cf Subcatchment 153S: PR-CB 10+84 Runoff Area=15,593 sf 75.41% Impervious Runoff Depth=5.56" Flow Length=200' Tc=5.0 min CN=92 Runoff=2.19 cfs 7,227 cf ' Subcatchment 154S: PR-CB 9+50RT Runoff Area=16,298 sf 60.58% Impervious Runoff Depth=5.22" Flow Length=330' Tc=5.0 min CN=89 Runoff=2.20 cfs 7,091 cf 1 Subcatchment 155S: EX-RES 2R Runoff Area=13,925 sf 26.47% Impervious Runoff Depth=4.24" Flow Length=105' Tc=5.0 min CN=80 Runoff=1.59 cfs 4,915 cf Subcatchment 156S: PR-POND 4 Runoff Area=21,635 sf 6.93% Impervious Runoff Depth=4.13" Flow Length=125' Tc=5.0 min CN=79 Runoff=2.39 cfs 7,445 cf Pond 78P: Proposed CULTEC 330XL Peak Elev=127.91' Storage=3,361 cf Inflow--l.89 cfs 6,057 cf ' Discarded=0.01 cfs 1,187 cf Secondary--0.69 cfs 2,043 cf Outflow--0.70 cfs 3,230 of Pond 142P: Detention Pond 1 Peak Elev=135.31' Storage=4,767 cf Inflow--6.56 cfs 20,636 cf ' Discarded=0.02 cfs 745 cf Primary--4.00 cfs 19,760 cf Secondary--0.00 cfs 0 cf Outflow--4.01 cfs 20,505 cf Pond 143P: Detention Pond 2 Peak EIev=131.30' Storage=9,906 cf Inflow=5.47 cfs 17,706 cf Discarded=0.03 cfs 2,427 cf Primary--0.27 cfs 15,280 cf Secondary--0.00 cfs 0 cf Outflow--0.30 cfs 17,707 cf Pond 144P: Detention Pond 4 Peak EIev=121.34' Storage=7,390 cf Inflow--8.76 cfs 28,178 cf Discarded=0.02 cfs 597 cf Primary--2.99 cfs 27,520 cf Secondary--0.00 cfs 0 cf Outflow--3.01 cfs 28,117 cf ' Pond 152P: Detention Pond 3 Peak Elev=117.35' Storage=7,097 cf Inflow--6.56 cfs 21,537 cf Discarded=0.02 cfs 2,062 cf Primary--2.07 cfs 18,987 cf Secondary--0.00 cfs 0 cf Outflow--2.10 cfs 21,049 of ' Link 109L: Total Surface Runoff discharging from project area Inflow--43.75 cfs 238,216 cf 13rimary=43.75 cfs 238,216 cf Link 128L: Runoff towards existing wetlands to the north Inflow=17.46 cfs 101,672 cf Primary=17.46 cfs 101,672 cf ' Link 130L: Runoff towards Isolated Wetland "B"series Inflow--4.97 cfs 20,063 cf Primary--4.97 cfs 20,063 cf ' Link 132L: Runoff towards Clark Avenue Drainage System Inflow--1 3.33 cfs 43,959 cf Primary=13.33 cfs 43,959 cf Link 139L: Runoff towards existing wetlands to the south Inflow--27.32 cfs 136,545 cf Primary--27.32 cfs 136,545 cf Link 141 L: Runoff towards Isolated Wetland "C"series. Inflow--3.47 cfs 13,326 cf Primary--3.47 cis 13,326 cf 1 1 Proposed Condition Watershed Analysis - Clark Avenue, Salem MA proposed-SUBMITTAL` Type M 24-hr 100 yr Rainfall=6.50" , Prepared by Microsoft Printed 8/18/2015 HydroCAD@ 9.10 s/n 06611 @2010 HydroCAD Software Solutions LLC Page 6 Total Runoff Area=872,510 sf Runoff Volume=282,130 cf Average Runoff Depth = 3.88" ' 81.90% Pervious =714,596 sf 18.10% Impervious = 157,914 sf 1 1 1 I t i I i i 1 ' Operation & Maintenance Plan Proposed Cluster Residential Subdivision Clarke Avenue, Salem MA August 14, 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 found 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 • Cultec Recharger 330XL Chambers • Street Sweeping • Constructed Stormwater Wetland (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. I � • 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.gov/dep/rggycle/­laws/cafacts.doc 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. ' Operation & Maintenance Plan Proposed Cluster Residential Subdivision Salem, MA August 14, 2015 j Once the depth of sediment is in excess of three (Y) inches, the affected Cultec Chambers j shall be excavated and the six (6) inch stone bed beneath them is removed and replaced with clean stone. I 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 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 first 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 ' One year after commissioning and everyyear following: -Check inlets and outlets for clogging and remove any debris as necessary 11 -Inspect the interior of the chambers via inspection ports and measure sediment or ' 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 ' • 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. ' Street Sweenine ' • Street sweeping should be conducted as needed or once minimum per year in the spring (March or April). 2 ' Operation & Maintenance Plan Proposed Cluster Residential Subdivision Salem, MA August 14, 2015 Constructed Stormwater Wetlands: • Constructed stormwater wetlands require small-scale maintenance at regular intervals to evaluate the health and composition of the plant species. • Carefully observe the stormwater wetland system over time. In the first three years after construction, inspect the constructed stormwater wetlands twice a year during both the ' growing and non-growing seasons. • During these inspections,record and map the following information: ' The types and distribution of the dominant wetland plants, The presence and distribution of planted wetland species, The presence and distribution of invasive wetland species (invasives must be removed), Indications that other species are replacing the planted wetland species; ' Percentage of standing water that is unvegetated (excluding the deep water cells which are not suitable for emergent plant growth); The maximum elevation and the vegetative condition in this zone, if the design elevation of the normal pool is being maintained for wetlands with extended zones; Stability of the sideslopes and berms, ' Stability of the original depth zones and the micro-topographic features; and Accumulation of sediment in the forebay and micropool, (remove once every 10 years if needed) ' Survival rate of plantings (dead plantings must be replanted) i I! r � r r 3 1 . - . �. . . ,y� . . . . : R SOIL�Gn OUP �N OF Mq.. '' � SSUMED TO BE D AT EDGE OF B V W �, s EXISTING C O N D I T I O N A . . . �. s , . \. / teA �� PETER M. q�yG DELL,JR. �.� ; � o° BLAIS � � WATERSHED & SOILS M A P � �' \ \. ; _ / � CIVIL �, `_ —. / / ._ _-- r-- .r.-- —... _� —�. / • \ T,e-S.o min � \\ \ , � _ __ __ ; .- ,� _ �--- �-� ._ � �_. - - �\� \� \ \ � � � TH E WOO D LAN DS _ _ ...- �. ,. f \\ \� \ _ " . .� 1 3s- _ _ � / j \ � j i �. �" ,--,�-.. � � '� '` �.���1- --- .\ \~' \\\ \ \\� '\ � - SCALE: 1" = 60' DATE: Au ust 14, 2015 �,,. � ,� � � _...t 46-.._ �` — -_ _�� ` `... --,...., \ �\� \ \ � � LIMIT O F WATERS H E D �,, / �_ -- �- -' �' ,- ..- ` t� ._ � .� --� -,. -..\ \\ \ \ �\\ � �' =20.Ot ACRES / \� � ANALYSIS �J ..� -� ._ .. . .... � .....-� \ .. "�. \ \ .�-- \ f/ _• v. _ _. ` �-.. • x r 3 i ` r � .` \ ,:�\\\ � \ \� �. �- -- _ _�.. � __ - _ � - - - _ --t,2_ _ ,. / - � SFA�RAGES _ �. '. / \��'�\ `' _-., �` "-- --- ---- —'—i-t+— ---,. 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