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Stormwater Management Report 070819 Reduced.pdf34 Dewey Court July 8, 2019 Northampton, Massachusetts Stormwater Management Report The Berkshire Design Group, Inc. Page i Table of Contents I. Introduction ........................................................................................................................1 II. Existing Conditions ..............................................................................................................1 III. Proposed Conditions ...........................................................................................................2 IV. Calculations and Design .......................................................................................................4 V. MADEP Stormwater Standards Compliance..........................................................................6 Figures Figure 1 Project Location Figure 2 Existing Conditions Figure 3 Site Plan Figure 4 Existing Hydrology Figure 5 Proposed Hydrology Appendix Appendix A NRCS Soil Report Appendix B Test Pit Report Appendix C Stormwater Hydrology Calculations Appendix D Groundwater Recharge Calculations Appendix E Water Quality Calculations Appendix F Stormwater Management System – Operation & Maintenance Plan Appendix G Massachusetts DEP Stormwater Checklist Referenced Documents Plan Set 34 Dewey Court Permit Set 34 Dewey Court July 8, 2019 Northampton, Massachusetts Stormwater Management Report The Berkshire Design Group, Inc. Page 1 Dewey Court Properties LLC is proposing to construct an apartment building and associated parking and landscaping alongside an existing house at 34 Dewey Court in Northampton, Massachusetts. The Berkshire Design Group has prepared a Stormwater Management and Erosion and Sedimentation Control Plan for the site, in compliance with the Massachusetts Stormwater Handbook and the Code of the City of Northampton. This report documents the proposed Stormwater Management Plan and that plan’s compliance with those standards. I. Introduction Thirty-four Dewey Court is a 1.3 acre lot currently comprised of a single family home, driveway, garage and open space. The proposed project is the redevelopment of the parcel, adding an apartment building and additional parking and landscaping and eliminating the existing garage while maintaining the single family home. Dewey Court is a cul-de-sac off of South Street (Route 10). Access to the parcel is at the end of Dewey Court and remains unchanged from existing conditions. The project location is shown in Figure 1. The work includes clearing, construction of proposed paving and building improvements, utilities, landscaping, fencing and stormwater improvements. The site includes impervious areas (access, roofs and patios) as well as a mix of open lawn, perennial beds and wooded areas generally sloping E/SE. Wetlands have been mapped on and off the parcel on the east and south borders. Runoff from the existing site discharges to the eastern wetland area which eventually drains to Fruit Street. Soil Data NRCS Soil Survey The NRCS Soil Survey reports that the on-site soils consist of fine sandy loam, silt loam and fine sand of Hydrologic Soil Group (HSG) B. The USGS Surficial Geology survey reports that the parcel is a stream terrace which includes sand, gravel and silt deposits. The NRCS Soil Report for the site is attached in Appendix A. Subsurface Exploration A total of three test pits were conducted at the Dewey Court site in April 2019. The soil evaluation report is attached as Appendix B. The test pits indicated that the soils included a layer of silt loam underlain with sand and gravel. Estimated high groundwater depth was found at 2.5 to 3 feet below the surface with standing water at 3.5 to 6 ft below the surface. For purposes of infiltration, B soils with a Rawls rate of 1.02 in/hour were assumed. The design for the project will include details and notes calling for the infiltration practices to be located on the sand and gravel portion of the profile and below the silt loam. Site Limits Site limits were based primarily on the parcel limits and an off-site area along Dewey Court which contributes to on site drainage and proposed stormwater management practices. II. Existing Conditions An Existing Conditions Plan is shown on Figure 2. 34 Dewey Court July 8, 2019 Northampton, Massachusetts Stormwater Management Report The Berkshire Design Group, Inc. Page 2 Existing Drainage Area The existing site was analyzed as one drainage area. The drainage area (labeled E1) is shown on the Existing Drainage Area Plan in Figure 4. A brief description of drainage patterns follows: The parcel is located on a terrace above Fruit Street with steep 2: 1 slopes at the edges of the terrace to the north and east. A broad drainage swale in the southern half of the lot also contributes to existing drainage patterns directing runoff to the eastern wetland area. Off-site contributions to the drainage include the pavement and sidewalk at the end of Dewey Court which is not captured in the existing stormwater system , a portion of the roof of the dwelling at 24 Dewey Court and some drainage off of the driveway for 25 Dewey Court. Existing impervious area on the parcel includes the entrance, driveway, garage and single-family home located on the terraced area and a small shed located at the eastern corner of the property. The property includes lawn and perennial beds as well as some large deciduous trees. The parcel boundary is wooded, and wetlands have been mapped to the east and south. Observations of existing conditions indicate that runoff from this parcel contributes to the mapped wetland east of the site. It also appears that the wetland drains into the existing sanitary sewer line which connects the sewer on Dewey Court to Fruit Street. III. Proposed Conditions The proposed plan is shown on the Site Plan in Figure 3. The proposed work generally maintains existing stormwater flow patterns. It is proposed to install a drainage system discharging to the stormwater system within Fruit Street. The two proposed underground detention and infiltration systems located under the parking lots will outlet into the proposed drainage system as well as the lower apartment roof. A discussion of runoff in each proposed drainage area follows. Proposed drainage areas are delineated in Figure 5. Proposed Drainage Areas Area P1a Area P1a includes the southern covered parking and offsite flows from 24 Dewey Court which are estimated at one half the dwelling’s roof. A stone filled trench with an underdrain will collect the covered parking roof as well as the off-site flows. Runoff will be routed to the underground detention and infiltration area within the south parking lot. Areas P1b Area P1b includes the end of Dewey Court, a portion of the driveway at 25 Dewey Court and a portion of the entrance drive. This area is collected on the south side of the entrance following existing drainage patterns with a curb cut to a rain garden. Pretreatment will be provided with a gravel diaphragm at the curb cut and a sod filter strip. An overflow yard drain will connect to the P1a stone trench. Area P2 Area P2 includes the southern half of the parking lot. This area will drain through a curb cut at the low point and to a rain garden. Overflow from the rain garden will be directed back to the 34 Dewey Court July 8, 2019 Northampton, Massachusetts Stormwater Management Report The Berkshire Design Group, Inc. Page 3 underground detention/infiltration system under the parking lot. Pretreatment will be provided with a gravel diaphragm at the curb and sod filter strip. Area P3 Area P3 includes the remainder of the south parking area. This area is graded to flow to a Hydrostorm HS 4i unit and then to the underground detention and infiltration system under the parking lot. Area P4 Area P4 includes runoff from the roof of the proposed apartment building. This clean runoff is discharged into the underground detention/infiltration area. Area P5 Area P5 includes an outdoor patio to the east of the site and a portion of the central roof. These areas drain to a rain garden which is designed to overflow to open space following existing conditions in larger storms. Area P6 Area P6 includes sheet flow from the open area between the proposed apartment and the existing house, all remaining sloped areas, the apartment rear roof and the house roof. The rear roof of the apartment building is captured into the proposed drainage system. Although area P6 is not treated for water quality the impervious areas are entirely comprised of roof drainage and walkways. Area P7 Area P7 includes the rooftop drainage of the covered parking to the north. This roof drainage is captured in a stone trench and directed to a rain garden at the northern edge of the property. Overflow from the rain garden is directed to the underground detention system under the north parking lot. Area P8 Area P8 includes the parking lot to the north. This area is directed to a Hydrostorm HS 4i unit which discharges to the underground detention system under the parking lot. Water Quality Existing impervious areas at the site include the circular access drive, driveway, garage, home and shed with no treatment facilities. The proposed redevelopment includes regrading of the existing entrance and driveway, and the construction of additional parking areas, apartment and patios. Four rain gardens and two Hydrostorm HS 4i hydrodynamic separators are provided to treat the majority of the runoff from the open parking areas and entrance driveway. When feasible, rooftop drainage is directed to underground detention and infiltration system. The rain gardens will provide 90% removal of TSS prior to discharge to the infiltration and detention facilities or to the outgoing drainage system. The Hydrostorm units will provide 94%-96% removal of TSS. 34 Dewey Court July 8, 2019 Northampton, Massachusetts Stormwater Management Report The Berkshire Design Group, Inc. Page 4 IV. Calculations and Design Water Quantity Drainage calculations were performed on Hydrocad Stormwater Modeling System version 10.0 using Soil Conservation Service (SCS) TR-20 methodology. The SCS method is based on rainfall observations, which were used to develop the Intensity-Duration-Frequency relationship, or IDF curve. The mass curve is a dimensionless distribution of rainfall over time, which indicates the fraction of the rainfall event that occurs at a given time within a 24-hour precipitation event. This synthetic distribution develops peak rates for storms of varying duration and intensities. The SCS distribution provides a cumulative rainfall at any point in time and allows volume-dependent routing runoff calculations to occur. These calculations are included in the appendices. Rainfall values are taken from the latest Northeast Regional Climate Center (NRCC) and are listed in Table 1. The watershed boundaries for calculation purposes are divided according to the proposed site grading and the natural limits of the drainage areas. The curve numbers (CNs) for the existing and proposed sub-catchment area are based on the soil type and the existing and proposed cover conditions at the site. Because this is a small site the post-development site times of concentration are all set at the minimum of 5 minutes and the pre-development time of concentration is set at 10 minutes. The stormwater design includes four rain gardens, two Hydrostorm units and two R-Tank underground systems located under the parking areas. The R-Tank systems discharge to manholes with outlet controls. The outflow is directed to the City of Northampton stormwater system within Fruit Street. Calculations were performed for the 2-, 10-, and 100-year frequency storms under existing and proposed conditions. The results of the calculations are presented in Table 1 below. Appendix C presents the HydroCAD output reports. Table 1. Runoff Summary Table Point of Analysis 2-Year Storm 3.07” 10-Year Storm 4.47” 100-Year Storm 7.68” Peak Flow Rate(cfs) Peak Flow Rate(cfs) Peak Flow Rate(cfs) Existing flow to Fruit Street 0.78 2.06 5.72 Proposed flow to Fruit Street 0.78 1.73 4.52 Percent change - -16% -21% Runoff from the site shows a decrease in peak flow for all storms between pre and post conditions. Stormwater facilities have been designed to reduce peak flow rates to lessen the impact on the City’s Fruit Street system. The modeling shows a 21% decrease in the 100-year storm, a 16% decrease during the 10-year storm and no increase in the 2-year storm. 34 Dewey Court July 8, 2019 Northampton, Massachusetts Stormwater Management Report The Berkshire Design Group, Inc. Page 5 Water Quality The proposed project has been designed with several green infrastructure features to enhance water quality. Impervious areas have been limited in size based on the proposed use and the apartment roof has been split into sections limiting single point discharges. The average TSS removal rate across the site including the existing areas is 65%, weighted by water quality area. The water quality volume is based on a depth of 0.5”. The proposed stormwater management system is designed to remove 80 to 96% of the average annual post-construction load of Total Suspended Solids (TSS) of the driveways and parking areas. This project is a redevelopment project and water quality has been provided to the maximum extent practicable. The design includes four rain gardens, stone lined conveyance channels and a large underground infiltration practice. Because of the steep grades in the rear portion of the site, the apartment rear roof is tied directly to the proposed stormwater system. In addition, the drainage from the roof of the existing dwelling remains unchanged from existing conditions which includes uncontrolled runoff to the wooded area at the back of the site. The design also allows sheet flow runoff from the front walkway to a newly landscaped area between the building. All the uncaptured runoff is relatively clean roof and walkway runoff. Calculations supporting these conclusions are included in Appendix D. Area P1a Runoff from the covered parking roof and the adjacent home roof enters a stone trench and is directed to the R-Tank infiltration system. Impervious Area: 3,745 sq. ft. Net Removal: 80% Area P1b Runoff from the end of Dewey Court and the top of the driveway is captured by a rain garden with stone diaphragm trench and sod filter strip. Impervious Area: 1,898 sq. ft. Net Removal: 90% Area P2 Runoff from the south parking lot is captured by a rain garden with stone diaphragm and sod filter strip. Impervious Area: 1,808 sq. ft. Net Removal: 90% Area P3 Runoff from the parking area is captured in a Hydrostorm unit. Impervious Area: 2,355 sq. ft. Net Removal: 96% 34 Dewey Court July 8, 2019 Northampton, Massachusetts Stormwater Management Report The Berkshire Design Group, Inc. Page 6 Area P4 Runoff from front apartment roof is directed to the R-Tank infiltration area. Impervious Area: 3,785 sq. ft. Net Removal: 80% Area P5 Runoff from the patio areas and central apartment roof is captured in a rain garden with stone diaphragm and sod filter strip. Impervious Area: 721 sq. ft. Net Removal: 90% Area P6 Runoff from the front walkway, existing home roofs sheet flows to a newly landscaped area and over existing undisturbed areas. The apartment rear roof is captured in the proposed drainage system. Impervious Area: 6,904 sq. ft. Net Removal: 0% - 45% (0% is used in the calculations) Area P7 Runoff from the covered parking is captured in a stone trench and treated in a rain garden. Impervious Area: 1,723 sq. ft. Net Removal: 90% Area P8 Runoff from the north parking area is captured and treated by a Hydrostorm unit. Impervious Area: 4,111 sq. ft. Net Removal: 94% Erosion & Sedimentation Control The project plan set includes provisions for erosion control during construction. Erosion control barrier is included in select locations at the lower end of the site to prevent migration of sediment into the existing wetlands or offsite during construction. “Silt soxx” are proposed for down-slope protection for ease of transport, installation and removal. V. MADEP Stormwater Standards Compliance The following section details how the project will meet the DEP Stormwater Management Policy’s ten stormwater management standards. 34 Dewey Court July 8, 2019 Northampton, Massachusetts Stormwater Management Report The Berkshire Design Group, Inc. Page 7 LID Low-impact design principles were considered during the development of the stormwater management plan for this project and have been implemented to the extent practicable. Four rain gardens throughout the site collect runoff from impervious areas. The covered parking area roofs sheet flow to stone lined trenches. Two Hydrostorm catch basins collect most of the parking and driveway surfaces and large underground detention systems are designed to infiltrate. Standard 1 - Untreated Stormwater Discharge The proposed project includes a drainage system designed to capture flows from the R-tank systems and gutter flows from the rear apartment roof and existing home. This runoff is generally clean and will be connected to the storm drain system within Fruit Street. The proposed site does not discharge runoff directly to wetland areas. Runoff from the existing home roof is directed to vegetated buffers. And uncaptured runoff from other proposed impervious areas sheet flows through vegetated buffers prior to entering the mapped wetlands. Standard 2 - Post-Development Peak Discharge Rates The proposed stormwater management system is designed so that post-development peak discharge rates are less than pre-development peak discharge rates leaving the site. These results are discussed in detail under “Peak Runoff Rate” in Section IV, above. Standard 3 - Recharge to Groundwater Groundwater recharge is analyzed under the 2-year design storm. The proposed site is expected to produce 0.78 cfs of runoff in the 2-year storm. The design includes capacity to infiltrate 3,442 cf. Calculations of recharge (see Appendix D) show that the storage volume provided for recharge exceeds the requirement. Standard 4 – Water Quality Seventy-four percent of the entire site’s impervious area (existing and proposed) is captured by BMPs designed to remove at least 80% TSS. The remaining 26% is comprised of roofs and walkways. Overall the TSS removal for the site is 65%. Because the site is a re-development project and the design includes multiple LID practices, the lower TSS removal is acceptable. The total water quality volume provided in BMPs exceeds the required volume. The water quality volume is calculated based on 0.5”/sf. Further discussion of this standard is included under “Water Quality” in Section III and in Appendix E. Standard 5 - Higher Potential Pollutant Loads The proposed project is not expected to yield high potential pollutant loads. Standard 6 - Protection of Critical Areas The project is not located within a critical area. 34 Dewey Court July 8, 2019 Northampton, Massachusetts Stormwater Management Report The Berkshire Design Group, Inc. Page 8 Standard 7 - Redevelopment Projects This project is a redevelopment project. Although the existing driveway will be re-used, the grading will be altered so that the area can be captured and treated. The existing home roof drainage patterns will remain. Standards 2 has been met, and standards 3 and 4 are met to the maximum extent practicable. Standards 5 and 6 do not apply to this project. Standard 1 has been met and improved from existing conditions by the addition of four rain gardens, 2 Hydrostorm HS 4i units and a storm drain system. Standard 8 - Erosion/Sediment Control A proposed Erosion & Sediment Control Plan has been developed, and is shown in the plan set. A full Stormwater Pollution Prevention Plan will be developed by the contractor prior to any disturbance of the site. Standard 9 - Operation/Maintenance Plan An Operation and Maintenance Plan for the proposed project is included in Appendix F. It includes general controls for construction and long term maintenance of the stormwater management system. Standard 10 – Prohibition of Illicit Discharges No Illicit Discharge Compliance Statement is included with this report. It will be the responsibility of the owner to submit a statement prior to the discharge of any stormwater to post-construction BMPs. 34 Dewey Court Northampton, Massachusetts Stormwater Management Report The Berkshire Design Group, Inc. FIGURES P R O J E C T L O C A T I O N C h e c k e d B y : D r a w n B y : R e v i s i o n s S c a l e : D a t e : S h e e t N u m b e r T h i s d r a w i n g i s n o t i n t e n d e d n o r s h a l l i t b e u s e d f o r c o n s t r u c t i o n p u r p o s e s u n l e s s t h e s i g n e d p r o f e s s i o n a l s e a l o f a r e g i s t e r e d l a n d s c a p e a r c h i t e c t , c i v i l e n g i n e e r o r l a n d s u r v e y o r e m p l o y e d b y T h e B e r k s h i r e D e s i g n G r o u p , I n c . i s a f f i x e d a b o v e . D o n o t s c a l e d r a w i n g f o r q u a n t i t y t a k e - o f f s o r c o n s t r u c t i o n . U s e w r i t t e n d i m e n s i o n s o n l y . I f d i m e n s i o n s a r e i n c o m p l e t e , c o n t a c t T h e B e r k s h i r e D e s i g n G r o u p I n c . f o r c l a r i f i c a t i o n . C o p y r i g h t T h e B e r k s h i r e D e s i g n G r o u p , I n c . T h i s d r a w i n g a n d a l l o f i t s c o n t e n t s a r e t h e e x p r e s s p r o p e r t y o f T h e B e r k s h i r e D e s i g n G r o u p , I n c . , a n d s h a l l n o t b e c o p i e d o r u s e d i n a n y w a y w i t h o u t t h e w r i t t e n c o n s e n t o f T h e B e r k s h i r e D e s i g n G r o u p , I n c . c 3 4 D E W E Y C O U R T N O R T H A M P T O N , M A S S A C H U S E T T S W e b : h t t p : / / w w w . b e r k s h i r e d e s i g n . c o m E m a i l : b d g @ b e r k s h i r e d e s i g n . c o m ( 4 1 3 ) 5 8 2 - 7 0 0 0 4 A l l e n P l a c e , N o r t h a m p t o n , M a s s a c h u s e t t s 0 1 0 6 0 F A X ( 4 1 3 ) 5 8 2 - 7 0 0 5 L a n d s c a p e A r c h i t e c t u r e C i v i l E n g i n e e r i n g P l a n n i n g B e r k s h i r e G r o u p D e s i g n L a n d S u r v e y i n g F I G 1 J U N E 1 7 , 2 0 1 9 1 " = 3 0 0 ' L C L O C U S 0 6 0 0 3 0 0 1 5 0 9 0 0 Plantings O O O O X X X X X X X X X X X X X X MH MH W/ F S h e d 1 Story Wood Frame Garage 1 Story W/F Garage 1 StyDeck Treeline Treeline Woods Woods Path Pa t h o o o oo 23" 28" 28" 28" (Dead)20" 32" 20" 20" 22" 31" 21" 27" 22" 35" 46" 8" (Dead) 12" 12"(Dead) P l a n t i n g s Plantings Lawn Plantings 39" 35" Shrub Shrubs 28" 22" 39" 48" 27" 21" 27" 27" Treeline 28" 27"20" 22" 22" 33" 22" 26" 41" 32" 30" 24" 25" 22" 20" #34 2 Story W/F House 1 S t o r y 1 Sty 1 Sty 1 Sty 10" 46" Lawn Bitumino u s D r i v e Plan t i n g s Plantings CB Rim:133.44' Sump:131.4' CB Rim:133.57' Sump:131.4' Bituminous Drive Shrubs/ Plantings B i t . C u r b B i t u m i n o u s W a l k W.V. SMH(Record) Rim:133.80' Not Opened(Car Over) Record Invert= -5.73' Bituminous Drive 4"PVC Invert Out: 118.88' Stone Retaining Walls Concrete Walk Overhang R.D. R.D. R.D. R.D. Guy Wire UP 03 FF(Thresh) El:133.80' FF(Thresh) El:135.99' FF(Thresh) El:128.54' Plantings Brick & Stone Porch w/ Canopy St o n e W a l k Stone Patio/ Brick & Stone Steps Wooden Stairs Concrete Walk & Curb Chimney 13 4 13 2 13 3 131 13 0 128 129 131 131 131 130 129 128 127 126125 1 2 1 1 2 2 123 124 1 2 0 11 9 118 117 1 3 4 13 3 134 1 3 5 135 1 3 4 134 133 132 13 1 13 3 132 1 3 0 13 1 125 12 0 11 8 129 133 132 131 130 129 128 13 4 13 0 12 5 120 118 119 Lawn St o n e C u r b S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S MH Rim:127.57' Record Sewer Line S W W W W TBM= Top Spindle Of Hydrant El:136.12' D 4" Water R e c o r d S e w e r L i n e 8 " V C 1 2 2 . 1 ' 8 " V C 1 2 2 . 0 ' Bit . C u r b 10" A C 131. 4 ' TP-1 TP-2 TP-3 Checked By: Drawn By: Revisions Scale: Date:Sheet Number This drawing is not intended nor shall it be used for construction purposes unless the signed professional seal of a registered landscape architect, civil engineer or land surveyor employed by The Berkshire Design Group, Inc. is affixed above. Web: http://www.berkshiredesign.com Email: bdg@berkshiredesign.com (413) 582-7000 4 Allen Place, Northampton, Massachusetts 01060 FAX (413) 582-7005 Landscape Architecture Civil Engineering Planning Berkshire Group Design Do not scale drawing for quantity take-offs or construction. Use written dimensions only. If dimensions are incomplete, contact The Berkshire Design Group Inc. for clarification. Land Surveying Copyright The Berkshire Design Group, Inc. This drawing and all of its contents are the express property of The Berkshire Design Group, Inc., and shall not be copied or used in any way without the written consent of The BerkshireDesign Group, Inc. c 34 DEWEY COURT NORTHAMPTON, MASSACHUSETTS FIG 2 JUNE 17, 2019 1"=30' LC EXISTING CONDITIONS 0 603015 90 D D D D D 13 4 134 134 13 4 13 3 134 133 1 3 4 1 3 3 13 4 132 13 3 1 3 3 1 3 2 1 3 3 131 130 131 133 13 4 134 133 132 125 130 132 O O O O X X X X X X X X X X X X X X MH MH o o o oo 1 3 4 13 2 13 3 131 130 128 129 131 131 131 130 129 128 127 126125 1 2 1 1 2 2 123 124 1 2 0 11 9 118 117 1 3 4 13 3 134 1 3 5 135 1 3 4 134 133 132 1 3 1 13 3 132 1 3 0 13 1 125 120 11 8 129 133 132 131 130 129 128 13 4 13 0 12 5 120 118 119 RAIN GARDEN 4 RAIN GARDEN 3 STONE-FILLED DRIP EDGE TRENCH STONE-FILLED DRIP EDGE TRENCH RAIN GARDEN 1 RAIN GARDEN 2CURB OPENING CURB OPENING SHED TO BE REMOVED COVERED P A R K I N G COVERED P A R K I N G PROPOSED APARTMENT BUILDING EX. HOUSE D E W E Y C O U R T R-TANK DETENTION AND INFILTRATION SYSTEM - 1 R-TANK DETENTION SYSTEM - 2 FRUIT STREET Checked By: Drawn By: Revisions Scale: Date:Sheet Number This drawing is not intended nor shall it be used for construction purposes unless the signed professional seal of a registered landscape architect, civil engineer or land surveyor employed by The Berkshire Design Group, Inc. is affixed above. Web: http://www.berkshiredesign.com Email: bdg@berkshiredesign.com (413) 582-7000 4 Allen Place, Northampton, Massachusetts 01060 FAX (413) 582-7005 Landscape Architecture Civil Engineering Planning Berkshire Group Design Do not scale drawing for quantity take-offs or construction. Use written dimensions only. If dimensions are incomplete, contact The Berkshire Design Group Inc. for clarification. Land Surveying Copyright The Berkshire Design Group, Inc. This drawing and all of its contents are the express property of The Berkshire Design Group, Inc., and shall not be copied or used in any way without the written consent of The BerkshireDesign Group, Inc. c 34 DEWEY COURT NORTHAMPTON, MASSACHUSETTS FIG 3 JULY 7, 2019 1"=30' LC SITE PLAN 0 603015 90 Plantings O O O O X X X X X X X X X X X X X X MH MH W/ F S h e d 1 Story Wood Frame Garage 1 Story W/F Garage 1 StyDeck Treeline Treeline Woods Woods Path Pa t h o o o oo 23" 28" 28" 28" (Dead)20" 32" 20" 20" 22" 31" 21" 27" 22" 35" 46" 8" (Dead) 12" 12"(Dead) P l a n t i n g s Plantings Lawn Plantings 39" 35" Shrub Shrubs 28" 22" 39" 48" 27" 21" 27" 27" Treeline 28" 27"20" 22" 22" 33" 22" 26" 41" 32" 30" 24" 25" 22" 20" #34 2 Story W/F House 1 S t o r y 1 Sty 1 Sty 1 Sty 10" 46" Lawn Bitumino u s D r i v e Plan t i n g s Plantings CBRim:133.44' Sump:131.4' CB Rim:133.57' Sump:131.4' Bituminous Drive Shrubs/Plantings B i t . C u r b B i t u m i n o u s W a l k W.V. G.V. SMH(Record) Rim:133.80' Not Opened(Car Over) Record Invert= -5.73' Bituminous Drive 4"PVC Invert Out: 118.88' Stone Retaining Walls Concrete Walk Overhang R.D. R.D. R.D. R.D. Guy Wire UP 03 FF(Thresh) El:133.80' FF(Thresh) El:135.99' FF(Thresh) El:128.54' Plantings Brick & Stone Porch w/ Canopy St o n e W a l k Stone Patio/ Brick & Stone Steps Wooden Stairs Concrete Walk & Curb Chimney 13 4 13 2 13 3 131 13 0 128 129 131 131 131 130 129 128 127 126125 1 2 1 1 2 2 123 124 1 2 0 11 9 118 117 1 3 4 13 3 134 1 3 5 135 1 3 4 134 133 132 13 1 13 3 132 1 3 0 13 1 125 12 0 11 8 129 133 132 131 130 129 128 13 4 13 0 12 5 120 118 119 Lawn St o n e C u r b S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S MH Rim:127.57' Record Sewer Line S W W W W W D 4" Water R e c o r d S e w e r L i n e 8 " V C 1 2 2 . 1 ' 8 " V C 1 2 2 . 0 ' Bit . C u r b 10" A C 131 . 4 ' TP-1 TP-2 TP-3 Existing House 24 Dewey Ct SITE/DRAINAGE AREA SUMMARYTOTAL SITE: 56,543 SF TOTAL DRAINAGE AREA: 59,724 SFIMPERVIOUS: 9,140 SFOPEN SPACE: 50,584 SFSOIL HYDROLOGIC GROUP: B Checked By: Drawn By: Revisions Scale: Date:Sheet Number This drawing is not intended nor shall it be used for construction purposes unless the signed professional seal of a registered landscape architect, civil engineer or land surveyor employed by The Berkshire Design Group, Inc. is affixed above. Web: http://www.berkshiredesign.com Email: bdg@berkshiredesign.com (413) 582-7000 4 Allen Place, Northampton, Massachusetts 01060 FAX (413) 582-7005 Landscape Architecture Civil Engineering Planning Berkshire Group Design Do not scale drawing for quantity take-offs or construction. Use written dimensions only. If dimensions are incomplete, contact The Berkshire Design Group Inc. for clarification. Land Surveying Copyright The Berkshire Design Group, Inc. This drawing and all of its contents are the express property of The Berkshire Design Group, Inc., and shall not be copied or used in any way without the written consent of The BerkshireDesign Group, Inc. c 34 DEWEY COURT NORTHAMPTON, MASSACHUSETTS FIG 4 JUNE 17, 2019 1"=30' LC EXISTING DRAINAGE 0 603015 90 Existing Hydrology - Summary impervious area (sq. ft.) open space (sq. ft.) total area (sq. ft.) E1 9,140 50,584 59,724 Total 9,140 50,584 59,724 SITE/DRAINAGE AREA SUMMARY TOTAL SITE: 56,543 SF TOTAL DRAINAGE AREA: 59,724 SF IMPERVIOUS: 27,050 SF OPEN SPACE: 32,674 SF SOIL HYDROLOGIC GROUP: B Existing House 24 Dewey Ct D D D D MH MH FF(Thresh) El:133.80' FF(Thresh) El:135.99' FF(Thresh) El:128.54' MH MH FF(Thresh) El:133.80' FF(Thresh) El:135.99' FF(Thresh) El:128.54' MH MH FF(Thresh) El:133.80' FF(Thresh) El:135.99' FF(Thresh) El:128.54' MH MH FF(Thresh) El:133.80' FF(Thresh) El:135.99' FF(Thresh) El:128.54' MH MH FF(Thresh) El:133.80' FF(Thresh) El:135.99' FF(Thresh) El:128.54' MH MH FF(Thresh) El:133.80' FF(Thresh) El:135.99' FF(Thresh) El:128.54' MH MH FF(Thresh) El:133.80' FF(Thresh) El:135.99' FF(Thresh) El:128.54' MH MH FF(Thresh) El:133.80' FF(Thresh) El:135.99' FF(Thresh) El:128.54' MH MH FF(Thresh) El:133.80' FF(Thresh) El:135.99' FF(Thresh) El:128.54' MH MH FF(Thresh) El:133.80' FF(Thresh) El:135.99' FF(Thresh) El:128.54' MH MH FF(Thresh) El:133.80' FF(Thresh) El:135.99' FF(Thresh) El:128.54' MH MH FF(Thresh) El:133.80' FF(Thresh) El:135.99' FF(Thresh) El:128.54' MH MH FF(Thresh) El:133.80' FF(Thresh) El:135.99' FF(Thresh) El:128.54' MH MH FF(Thresh) El:133.80' FF(Thresh) El:135.99' FF(Thresh) El:128.54' MH MH FF(Thresh) El:133.80' FF(Thresh) El:135.99' FF(Thresh) El:128.54' MH MH FF(Thresh) El:133.80' FF(Thresh) El:135.99' FF(Thresh) El:128.54' MH MH FF(Thresh) El:133.80' FF(Thresh) El:135.99' FF(Thresh) El:128.54' MH MH FF(Thresh) El:133.80' FF(Thresh) El:135.99' FF(Thresh) El:128.54' MH MH FF(Thresh) El:133.80' FF(Thresh) El:135.99' FF(Thresh) El:128.54' MH MH FF(Thresh) El:133.80' FF(Thresh) El:135.99' FF(Thresh) El:128.54' MH MH FF(Thresh) El:133.80' FF(Thresh) El:135.99' FF(Thresh) El:128.54' MH MH FF(Thresh) El:133.80' FF(Thresh) El:135.99' FF(Thresh) El:128.54' MH MH FF(Thresh) El:133.80' FF(Thresh) El:135.99' FF(Thresh) El:128.54' MH MH FF(Thresh) El:133.80' FF(Thresh) El:135.99' FF(Thresh) El:128.54' MH MH FF(Thresh) El:133.80' FF(Thresh) El:135.99' FF(Thresh) El:128.54' MH MH FF(Thresh) El:133.80' FF(Thresh) El:135.99' FF(Thresh) El:128.54' MH MH FF(Thresh) El:133.80' FF(Thresh) El:135.99' FF(Thresh) El:128.54' MH MH FF(Thresh) El:133.80' FF(Thresh) El:135.99' FF(Thresh) El:128.54' O O O O X X X X X X X X X X X X X X MH MH Path Pa t h o o o oo Shrub Shrubs Shrubs/ Plantings B i t . C u r b W.V. G.V. Stone Retaining Walls Overhang Guy Wire UP 03 FF(Thresh) El:133.80' FF(Thresh) El:135.99' FF(Thresh) El:128.54' 13 4 13 2 13 3 131 13 0 128 129 131 131 131 130 129 128 127 126125 1 2 1 1 2 2 123 124 12 0 11 9 118 117 1 3 4 13 3 134 1 3 5 135 1 3 4 134 133 132 1 3 1 13 3 132 1 3 0 13 1 125 120 11 8 12 9 13 3 132 131 130 129 128 13 4 13 0 12 5 120 118 119 S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S Record Sewer Line S W W W W W W D D D D 4" Water R e c o r d S e w e r L i n e 8 " V C 1 2 2 . 1 ' 8 " V C 1 2 2 . 0 ' Bit . C u r b 10"A C 131. 4 ' 1 2 " A C 1 3 1 . 6 ' 5 0 ' W i d e C i t y W a y w e y C o u r t P4 P1a P2 P3 P6 P1b P5 P7 P8 D D D D D 13 4 134 134 13 4 13 3 134 133 1 3 4 1 3 3 13 4 132 13 3 1 3 3 1 3 2 1 3 3 131 130 131 133 13 4 134 133 132 125 130 132 D Checked By: Drawn By: Revisions Scale: Date:Sheet Number This drawing is not intended nor shall it be used for construction purposes unless the signed professional seal of a registered landscape architect, civil engineer or land surveyor employed by The Berkshire Design Group, Inc. is affixed above. Web: http://www.berkshiredesign.com Email: bdg@berkshiredesign.com (413) 582-7000 4 Allen Place, Northampton, Massachusetts 01060 FAX (413) 582-7005 Landscape Architecture Civil Engineering Planning Berkshire Group Design Do not scale drawing for quantity take-offs or construction. Use written dimensions only. If dimensions are incomplete, contact The Berkshire Design Group Inc. for clarification. Land Surveying Copyright The Berkshire Design Group, Inc. This drawing and all of its contents are the express property of The Berkshire Design Group, Inc., and shall not be copied or used in any way without the written consent of The BerkshireDesign Group, Inc. c 34 DEWEY COURT NORTHAMPTON, MASSACHUSETTS FIG 5 JULY 8, 2019 1"=30' LC PROPOSED DRAINAGE 0 603015 90 Proposed Hydrology - Summary impervious area (sq. ft.) open space (sq. ft.) total area (sq. ft.) P1a 3,745 2,762 6,507 P1b 1,898 843 2,741 P2 1,808 535 2,343 P3 2,355 144 2,499 P4 3,785 0 3,785 P5 721 782 1,503 P6 6,904 24,711 31,615 P7 1,723 2,203 3,926 P8 4,111 694 4,805 Total 27,050 32,674 59,724 34 Dewey Court Northampton, Massachusetts Stormwater Management Report The Berkshire Design Group, Inc. Appendix A– NRCS Soils Report United States Department of Agriculture A product of the National Cooperative Soil Survey, a joint effort of the United States Department of Agriculture and other Federal agencies, State agencies including the Agricultural Experiment Stations, and local participants Custom Soil Resource Report for Hampshire County, Massachusetts, Central Part 34 Dewey Court, Northampton, MA Natural Resources Conservation Service April 18, 2019 Preface Soil surveys contain information that affects land use planning in survey areas. They highlight soil limitations that affect various land uses and provide information about the properties of the soils in the survey areas. Soil surveys are designed for many different users, including farmers, ranchers, foresters, agronomists, urban planners, community officials, engineers, developers, builders, and home buyers. Also, conservationists, teachers, students, and specialists in recreation, waste disposal, and pollution control can use the surveys to help them understand, protect, or enhance the environment. Various land use regulations of Federal, State, and local governments may impose special restrictions on land use or land treatment. Soil surveys identify soil properties that are used in making various land use or land treatment decisions. The information is intended to help the land users identify and reduce the effects of soil limitations on various land uses. The landowner or user is responsible for identifying and complying with existing laws and regulations. Although soil survey information can be used for general farm, local, and wider area planning, onsite investigation is needed to supplement this information in some cases. Examples include soil quality assessments (http://www.nrcs.usda.gov/wps/ portal/nrcs/main/soils/health/) and certain conservation and engineering applications. For more detailed information, contact your local USDA Service Center (https://offices.sc.egov.usda.gov/locator/app?agency=nrcs) or your NRCS State Soil Scientist (http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/contactus/? cid=nrcs142p2_053951). Great differences in soil properties can occur within short distances. Some soils are seasonally wet or subject to flooding. Some are too unstable to be used as a foundation for buildings or roads. Clayey or wet soils are poorly suited to use as septic tank absorption fields. A high water table makes a soil poorly suited to basements or underground installations. The National Cooperative Soil Survey is a joint effort of the United States Department of Agriculture and other Federal agencies, State agencies including the Agricultural Experiment Stations, and local agencies. The Natural Resources Conservation Service (NRCS) has leadership for the Federal part of the National Cooperative Soil Survey. Information about soils is updated periodically. Updated information is available through the NRCS Web Soil Survey, the site for official soil survey information. The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, age, disability, and where applicable, sex, marital status, familial status, parental status, religion, sexual orientation, genetic information, political beliefs, reprisal, or because all or a part of an individual's income is derived from any public assistance program. (Not all prohibited bases apply to all programs.) Persons with disabilities who require 2 alternative means for communication of program information (Braille, large print, audiotape, etc.) should contact USDA's TARGET Center at (202) 720-2600 (voice and TDD). To file a complaint of discrimination, write to USDA, Director, Office of Civil Rights, 1400 Independence Avenue, S.W., Washington, D.C. 20250-9410 or call (800) 795-3272 (voice) or (202) 720-6382 (TDD). USDA is an equal opportunity provider and employer. 3 Contents Preface....................................................................................................................2 How Soil Surveys Are Made..................................................................................5 Soil Map..................................................................................................................8 Soil Map................................................................................................................9 Legend................................................................................................................10 Map Unit Legend................................................................................................12 Map Unit Descriptions........................................................................................12 Hampshire County, Massachusetts, Central Part...........................................14 98A—Winooski silt loam, 0 to 3 percent slopes..........................................14 253B—Hinckley loamy sand, 3 to 8 percent slopes....................................15 258A—Amostown fine sandy loam, 0 to 3 percent slopes..........................16 744A—Hadley-Winooski-Urban land complex, 0 to 3 percent slopes.........18 References............................................................................................................20 4 How Soil Surveys Are Made Soil surveys are made to provide information about the soils and miscellaneous areas in a specific area. They include a description of the soils and miscellaneous areas and their location on the landscape and tables that show soil properties and limitations affecting various uses. Soil scientists observed the steepness, length, and shape of the slopes; the general pattern of drainage; the kinds of crops and native plants; and the kinds of bedrock. They observed and described many soil profiles. A soil profile is the sequence of natural layers, or horizons, in a soil. The profile extends from the surface down into the unconsolidated material in which the soil formed or from the surface down to bedrock. The unconsolidated material is devoid of roots and other living organisms and has not been changed by other biological activity. Currently, soils are mapped according to the boundaries of major land resource areas (MLRAs). MLRAs are geographically associated land resource units that share common characteristics related to physiography, geology, climate, water resources, soils, biological resources, and land uses (USDA, 2006). Soil survey areas typically consist of parts of one or more MLRA. The soils and miscellaneous areas in a survey area occur in an orderly pattern that is related to the geology, landforms, relief, climate, and natural vegetation of the area. Each kind of soil and miscellaneous area is associated with a particular kind of landform or with a segment of the landform. By observing the soils and miscellaneous areas in the survey area and relating their position to specific segments of the landform, a soil scientist develops a concept, or model, of how they were formed. Thus, during mapping, this model enables the soil scientist to predict with a considerable degree of accuracy the kind of soil or miscellaneous area at a specific location on the landscape. Commonly, individual soils on the landscape merge into one another as their characteristics gradually change. To construct an accurate soil map, however, soil scientists must determine the boundaries between the soils. They can observe only a limited number of soil profiles. Nevertheless, these observations, supplemented by an understanding of the soil-vegetation-landscape relationship, are sufficient to verify predictions of the kinds of soil in an area and to determine the boundaries. Soil scientists recorded the characteristics of the soil profiles that they studied. They noted soil color, texture, size and shape of soil aggregates, kind and amount of rock fragments, distribution of plant roots, reaction, and other features that enable them to identify soils. After describing the soils in the survey area and determining their properties, the soil scientists assigned the soils to taxonomic classes (units). Taxonomic classes are concepts. Each taxonomic class has a set of soil characteristics with precisely defined limits. The classes are used as a basis for comparison to classify soils systematically. Soil taxonomy, the system of taxonomic classification used in the United States, is based mainly on the kind and character of soil properties and the arrangement of horizons within the profile. After the soil 5 scientists classified and named the soils in the survey area, they compared the individual soils with similar soils in the same taxonomic class in other areas so that they could confirm data and assemble additional data based on experience and research. The objective of soil mapping is not to delineate pure map unit components; the objective is to separate the landscape into landforms or landform segments that have similar use and management requirements. Each map unit is defined by a unique combination of soil components and/or miscellaneous areas in predictable proportions. Some components may be highly contrasting to the other components of the map unit. The presence of minor components in a map unit in no way diminishes the usefulness or accuracy of the data. The delineation of such landforms and landform segments on the map provides sufficient information for the development of resource plans. If intensive use of small areas is planned, onsite investigation is needed to define and locate the soils and miscellaneous areas. Soil scientists make many field observations in the process of producing a soil map. The frequency of observation is dependent upon several factors, including scale of mapping, intensity of mapping, design of map units, complexity of the landscape, and experience of the soil scientist. Observations are made to test and refine the soil-landscape model and predictions and to verify the classification of the soils at specific locations. Once the soil-landscape model is refined, a significantly smaller number of measurements of individual soil properties are made and recorded. These measurements may include field measurements, such as those for color, depth to bedrock, and texture, and laboratory measurements, such as those for content of sand, silt, clay, salt, and other components. Properties of each soil typically vary from one point to another across the landscape. Observations for map unit components are aggregated to develop ranges of characteristics for the components. The aggregated values are presented. Direct measurements do not exist for every property presented for every map unit component. Values for some properties are estimated from combinations of other properties. While a soil survey is in progress, samples of some of the soils in the area generally are collected for laboratory analyses and for engineering tests. Soil scientists interpret the data from these analyses and tests as well as the field-observed characteristics and the soil properties to determine the expected behavior of the soils under different uses. Interpretations for all of the soils are field tested through observation of the soils in different uses and under different levels of management. Some interpretations are modified to fit local conditions, and some new interpretations are developed to meet local needs. Data are assembled from other sources, such as research information, production records, and field experience of specialists. For example, data on crop yields under defined levels of management are assembled from farm records and from field or plot experiments on the same kinds of soil. Predictions about soil behavior are based not only on soil properties but also on such variables as climate and biological activity. Soil conditions are predictable over long periods of time, but they are not predictable from year to year. For example, soil scientists can predict with a fairly high degree of accuracy that a given soil will have a high water table within certain depths in most years, but they cannot predict that a high water table will always be at a specific level in the soil on a specific date. After soil scientists located and identified the significant natural bodies of soil in the survey area, they drew the boundaries of these bodies on aerial photographs and Custom Soil Resource Report 6 identified each as a specific map unit. Aerial photographs show trees, buildings, fields, roads, and rivers, all of which help in locating boundaries accurately. Custom Soil Resource Report 7 Soil Map The soil map section includes the soil map for the defined area of interest, a list of soil map units on the map and extent of each map unit, and cartographic symbols displayed on the map. Also presented are various metadata about data used to produce the map, and a description of each soil map unit. 8 9 Custom Soil Resource Report Soil Map 46 8 7 1 8 0 46 8 7 2 2 0 46 8 7 2 6 0 46 8 7 3 0 0 46 8 7 3 4 0 46 8 7 3 8 0 46 8 7 4 2 0 46 8 7 4 6 0 46 8 7 5 0 0 46 8 7 1 8 0 46 8 7 2 2 0 46 8 7 2 6 0 46 8 7 3 0 0 46 8 7 3 4 0 46 8 7 3 8 0 46 8 7 4 2 0 46 8 7 4 6 0 46 8 7 5 0 0 695100 695140 695180 695220 695260 695300 695340 695100 695140 695180 695220 695260 695300 695340 42° 18' 55'' N 72 ° 3 7 ' 5 8 ' ' W 42° 18' 55'' N 72 ° 3 7 ' 4 6 ' ' W 42° 18' 44'' N 72 ° 3 7 ' 5 8 ' ' W 42° 18' 44'' N 72 ° 3 7 ' 4 6 ' ' W N Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 18N WGS84 0 50 100 200 300 Feet 0 25 50 100 150 Meters Map Scale: 1:1,730 if printed on A portrait (8.5" x 11") sheet. Soil Map may not be valid at this scale. MAP LEGEND MAP INFORMATION Area of Interest (AOI) Area of Interest (AOI) Soils Soil Map Unit Polygons Soil Map Unit Lines Soil Map Unit Points Special Point Features Blowout Borrow Pit Clay Spot Closed Depression Gravel Pit Gravelly Spot Landfill Lava Flow Marsh or swamp Mine or Quarry Miscellaneous Water Perennial Water Rock Outcrop Saline Spot Sandy Spot Severely Eroded Spot Sinkhole Slide or Slip Sodic Spot Spoil Area Stony Spot Very Stony Spot Wet Spot Other Special Line Features Water Features Streams and Canals Transportation Rails Interstate Highways US Routes Major Roads Local Roads Background Aerial Photography The soil surveys that comprise your AOI were mapped at 1:15,800. Warning: Soil Map may not be valid at this scale. Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale. Please rely on the bar scale on each map sheet for map measurements. Source of Map: Natural Resources Conservation Service Web Soil Survey URL: Coordinate System: Web Mercator (EPSG:3857) Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts distance and area. A projection that preserves area, such as the Albers equal-area conic projection, should be used if more accurate calculations of distance or area are required. This product is generated from the USDA-NRCS certified data as of the version date(s) listed below. Soil Survey Area: Hampshire County, Massachusetts, Central Part Survey Area Data: Version 13, Sep 10, 2018 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Sep 29, 2013—Oct 16, 2016 The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background Custom Soil Resource Report 10 MAP LEGEND MAP INFORMATION imagery displayed on these maps. As a result, some minor shifting of map unit boundaries may be evident. Custom Soil Resource Report 11 Map Unit Legend Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI 98A Winooski silt loam, 0 to 3 percent slopes 2.0 14.2% 253B Hinckley loamy sand, 3 to 8 percent slopes 2.2 15.7% 258A Amostown fine sandy loam, 0 to 3 percent slopes 4.9 35.5% 744A Hadley-Winooski-Urban land complex, 0 to 3 percent slopes 4.8 34.5% Totals for Area of Interest 13.9 100.0% Map Unit Descriptions The map units delineated on the detailed soil maps in a soil survey represent the soils or miscellaneous areas in the survey area. The map unit descriptions, along with the maps, can be used to determine the composition and properties of a unit. A map unit delineation on a soil map represents an area dominated by one or more major kinds of soil or miscellaneous areas. A map unit is identified and named according to the taxonomic classification of the dominant soils. Within a taxonomic class there are precisely defined limits for the properties of the soils. On the landscape, however, the soils are natural phenomena, and they have the characteristic variability of all natural phenomena. Thus, the range of some observed properties may extend beyond the limits defined for a taxonomic class. Areas of soils of a single taxonomic class rarely, if ever, can be mapped without including areas of other taxonomic classes. Consequently, every map unit is made up of the soils or miscellaneous areas for which it is named and some minor components that belong to taxonomic classes other than those of the major soils. Most minor soils have properties similar to those of the dominant soil or soils in the map unit, and thus they do not affect use and management. These are called noncontrasting, or similar, components. They may or may not be mentioned in a particular map unit description. Other minor components, however, have properties and behavioral characteristics divergent enough to affect use or to require different management. These are called contrasting, or dissimilar, components. They generally are in small areas and could not be mapped separately because of the scale used. Some small areas of strongly contrasting soils or miscellaneous areas are identified by a special symbol on the maps. If included in the database for a given area, the contrasting minor components are identified in the map unit descriptions along with some characteristics of each. A few areas of minor components may not have been observed, and consequently they are not mentioned in the descriptions, especially where the pattern was so complex that it was impractical to make enough observations to identify all the soils and miscellaneous areas on the landscape. Custom Soil Resource Report 12 The presence of minor components in a map unit in no way diminishes the usefulness or accuracy of the data. The objective of mapping is not to delineate pure taxonomic classes but rather to separate the landscape into landforms or landform segments that have similar use and management requirements. The delineation of such segments on the map provides sufficient information for the development of resource plans. If intensive use of small areas is planned, however, onsite investigation is needed to define and locate the soils and miscellaneous areas. An identifying symbol precedes the map unit name in the map unit descriptions. Each description includes general facts about the unit and gives important soil properties and qualities. Soils that have profiles that are almost alike make up a soil series. Except for differences in texture of the surface layer, all the soils of a series have major horizons that are similar in composition, thickness, and arrangement. Soils of one series can differ in texture of the surface layer, slope, stoniness, salinity, degree of erosion, and other characteristics that affect their use. On the basis of such differences, a soil series is divided into soil phases. Most of the areas shown on the detailed soil maps are phases of soil series. The name of a soil phase commonly indicates a feature that affects use or management. For example, Alpha silt loam, 0 to 2 percent slopes, is a phase of the Alpha series. Some map units are made up of two or more major soils or miscellaneous areas. These map units are complexes, associations, or undifferentiated groups. A complex consists of two or more soils or miscellaneous areas in such an intricate pattern or in such small areas that they cannot be shown separately on the maps. The pattern and proportion of the soils or miscellaneous areas are somewhat similar in all areas. Alpha-Beta complex, 0 to 6 percent slopes, is an example. An association is made up of two or more geographically associated soils or miscellaneous areas that are shown as one unit on the maps. Because of present or anticipated uses of the map units in the survey area, it was not considered practical or necessary to map the soils or miscellaneous areas separately. The pattern and relative proportion of the soils or miscellaneous areas are somewhat similar. Alpha-Beta association, 0 to 2 percent slopes, is an example. An undifferentiated group is made up of two or more soils or miscellaneous areas that could be mapped individually but are mapped as one unit because similar interpretations can be made for use and management. The pattern and proportion of the soils or miscellaneous areas in a mapped area are not uniform. An area can be made up of only one of the major soils or miscellaneous areas, or it can be made up of all of them. Alpha and Beta soils, 0 to 2 percent slopes, is an example. Some surveys include miscellaneous areas. Such areas have little or no soil material and support little or no vegetation. Rock outcrop is an example. Custom Soil Resource Report 13 Hampshire County, Massachusetts, Central Part 98A—Winooski silt loam, 0 to 3 percent slopes Map Unit Setting National map unit symbol: 9b2p Mean annual precipitation: 40 to 50 inches Mean annual air temperature: 45 to 52 degrees F Frost-free period: 140 to 240 days Farmland classification: All areas are prime farmland Map Unit Composition Winooski and similar soils: 85 percent Minor components: 15 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Winooski Setting Landform: Flood plains Landform position (two-dimensional): Toeslope Landform position (three-dimensional): Tread Down-slope shape: Linear Across-slope shape: Concave Parent material: Silty alluvium Typical profile H1 - 0 to 17 inches: silt loam H2 - 17 to 60 inches: silt loam Properties and qualities Slope: 0 to 3 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Moderately well drained Runoff class: Very low Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.60 to 6.00 in/hr) Depth to water table: About 18 to 36 inches Frequency of flooding: Occasional Frequency of ponding: None Available water storage in profile: High (about 10.5 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 2w Hydrologic Soil Group: B Hydric soil rating: No Minor Components Hadley Percent of map unit: 10 percent Hydric soil rating: No Limerick Percent of map unit: 5 percent Custom Soil Resource Report 14 Landform: Alluvial flats Hydric soil rating: Yes 253B—Hinckley loamy sand, 3 to 8 percent slopes Map Unit Setting National map unit symbol: 2svm8 Elevation: 0 to 1,430 feet Mean annual precipitation: 36 to 53 inches Mean annual air temperature: 39 to 55 degrees F Frost-free period: 140 to 250 days Farmland classification: Farmland of statewide importance Map Unit Composition Hinckley and similar soils: 85 percent Minor components: 15 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Hinckley Setting Landform: Kame terraces, kames, outwash terraces, outwash deltas, outwash plains, eskers, moraines Landform position (two-dimensional): Summit, backslope, footslope, shoulder Landform position (three-dimensional): Nose slope, side slope, base slope, crest, tread, riser Down-slope shape: Linear, convex, concave Across-slope shape: Convex, linear, concave Parent material: Sandy and gravelly glaciofluvial deposits derived from gneiss and/or granite and/or schist Typical profile Oe - 0 to 1 inches: moderately decomposed plant material A - 1 to 8 inches: loamy sand Bw1 - 8 to 11 inches: gravelly loamy sand Bw2 - 11 to 16 inches: gravelly loamy sand BC - 16 to 19 inches: very gravelly loamy sand C - 19 to 65 inches: very gravelly sand Properties and qualities Slope: 3 to 8 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Excessively drained Runoff class: Very low Capacity of the most limiting layer to transmit water (Ksat): Moderately high to very high (1.42 to 99.90 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Salinity, maximum in profile: Nonsaline (0.0 to 1.9 mmhos/cm) Custom Soil Resource Report 15 Available water storage in profile: Very low (about 3.0 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 3s Hydrologic Soil Group: A Hydric soil rating: No Minor Components Windsor Percent of map unit: 8 percent Landform: Outwash deltas, outwash plains, kames, eskers, moraines, outwash terraces, kame terraces Landform position (two-dimensional): Summit, shoulder, backslope, footslope Landform position (three-dimensional): Nose slope, side slope, base slope, crest, riser, tread Down-slope shape: Linear, convex, concave Across-slope shape: Convex, linear, concave Hydric soil rating: No Sudbury Percent of map unit: 5 percent Landform: Outwash terraces, outwash deltas, kame terraces, outwash plains, moraines Landform position (two-dimensional): Backslope, footslope Landform position (three-dimensional): Side slope, base slope, head slope, tread Down-slope shape: Concave, linear Across-slope shape: Linear, concave Hydric soil rating: No Agawam Percent of map unit: 2 percent Landform: Eskers, moraines, outwash terraces, outwash deltas, kame terraces, outwash plains, kames Landform position (two-dimensional): Summit, shoulder, backslope, footslope Landform position (three-dimensional): Nose slope, side slope, base slope, crest, riser, tread Down-slope shape: Linear, convex, concave Across-slope shape: Convex, linear, concave Hydric soil rating: No 258A—Amostown fine sandy loam, 0 to 3 percent slopes Map Unit Setting National map unit symbol: 99z0 Mean annual precipitation: 40 to 50 inches Mean annual air temperature: 45 to 52 degrees F Frost-free period: 140 to 240 days Farmland classification: All areas are prime farmland Custom Soil Resource Report 16 Map Unit Composition Amostown and similar soils: 75 percent Minor components: 25 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Amostown Setting Landform: Terraces, deltas, outwash plains Landform position (two-dimensional): Summit, footslope Landform position (three-dimensional): Tread Down-slope shape: Convex Across-slope shape: Convex Parent material: Friable sandy glaciofluvial deposits over silty glaciolacustrine deposits Typical profile H1 - 0 to 7 inches: fine sandy loam H2 - 7 to 32 inches: fine sandy loam H3 - 32 to 60 inches: stratified very fine sand to silt loam Properties and qualities Slope: 0 to 3 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Moderately well drained Runoff class: Low Capacity of the most limiting layer to transmit water (Ksat): Moderately low to moderately high (0.06 to 0.60 in/hr) Depth to water table: About 18 to 36 inches Frequency of flooding: None Frequency of ponding: None Available water storage in profile: High (about 9.3 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 2w Hydrologic Soil Group: B Hydric soil rating: No Minor Components Pollux Percent of map unit: 15 percent Hydric soil rating: No Agawam Percent of map unit: 10 percent Hydric soil rating: No Custom Soil Resource Report 17 744A—Hadley-Winooski-Urban land complex, 0 to 3 percent slopes Map Unit Setting National map unit symbol: 9b03 Mean annual precipitation: 40 to 50 inches Mean annual air temperature: 45 to 52 degrees F Frost-free period: 120 to 240 days Farmland classification: Not prime farmland Map Unit Composition Hadley and similar soils: 45 percent Winooski and similar soils: 20 percent Urban land: 20 percent Minor components: 15 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Hadley Setting Landform: Flood plains Landform position (two-dimensional): Toeslope Landform position (three-dimensional): Tread Down-slope shape: Linear Across-slope shape: Linear Parent material: Friable coarse-silty alluvium Typical profile H1 - 0 to 11 inches: silt loam H2 - 11 to 68 inches: silt loam H3 - 68 to 72 inches: loamy fine sand Properties and qualities Slope: 0 to 3 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Well drained Runoff class: Low Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.60 to 2.00 in/hr) Depth to water table: About 48 to 72 inches Frequency of flooding: Occasional Frequency of ponding: None Available water storage in profile: High (about 10.5 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 1 Hydrologic Soil Group: B Hydric soil rating: No Custom Soil Resource Report 18 Description of Winooski Setting Landform: Flood plains Landform position (two-dimensional): Toeslope Landform position (three-dimensional): Tread Down-slope shape: Linear Across-slope shape: Linear Parent material: Silty alluvium Typical profile H1 - 0 to 17 inches: silt loam H2 - 17 to 60 inches: silt loam Properties and qualities Slope: 0 to 3 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Moderately well drained Runoff class: Very low Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.60 to 6.00 in/hr) Depth to water table: About 18 to 36 inches Frequency of flooding: Occasional Frequency of ponding: None Available water storage in profile: High (about 10.5 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 2w Hydrologic Soil Group: B Hydric soil rating: No Description of Urban Land Setting Parent material: Paved/filled Minor Components Limerick Percent of map unit: 10 percent Landform: Alluvial flats Hydric soil rating: Yes Saco Percent of map unit: 5 percent Landform: Alluvial flats Hydric soil rating: Yes Custom Soil Resource Report 19 References American Association of State Highway and Transportation Officials (AASHTO). 2004. Standard specifications for transportation materials and methods of sampling and testing. 24th edition. American Society for Testing and Materials (ASTM). 2005. Standard classification of soils for engineering purposes. ASTM Standard D2487-00. Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe. 1979. Classification of wetlands and deep-water habitats of the United States. U.S. Fish and Wildlife Service FWS/OBS-79/31. Federal Register. July 13, 1994. Changes in hydric soils of the United States. Federal Register. September 18, 2002. Hydric soils of the United States. Hurt, G.W., and L.M. Vasilas, editors. Version 6.0, 2006. Field indicators of hydric soils in the United States. National Research Council. 1995. Wetlands: Characteristics and boundaries. Soil Survey Division Staff. 1993. Soil survey manual. Soil Conservation Service. U.S. Department of Agriculture Handbook 18. http://www.nrcs.usda.gov/wps/portal/ nrcs/detail/national/soils/?cid=nrcs142p2_054262 Soil Survey Staff. 1999. Soil taxonomy: A basic system of soil classification for making and interpreting soil surveys. 2nd edition. Natural Resources Conservation Service, U.S. Department of Agriculture Handbook 436. http:// www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?cid=nrcs142p2_053577 Soil Survey Staff. 2010. Keys to soil taxonomy. 11th edition. U.S. Department of Agriculture, Natural Resources Conservation Service. http:// www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?cid=nrcs142p2_053580 Tiner, R.W., Jr. 1985. Wetlands of Delaware. U.S. Fish and Wildlife Service and Delaware Department of Natural Resources and Environmental Control, Wetlands Section. United States Army Corps of Engineers, Environmental Laboratory. 1987. Corps of Engineers wetlands delineation manual. Waterways Experiment Station Technical Report Y-87-1. United States Department of Agriculture, Natural Resources Conservation Service. National forestry manual. http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/ home/?cid=nrcs142p2_053374 United States Department of Agriculture, Natural Resources Conservation Service. National range and pasture handbook. http://www.nrcs.usda.gov/wps/portal/nrcs/ detail/national/landuse/rangepasture/?cid=stelprdb1043084 20 United States Department of Agriculture, Natural Resources Conservation Service. National soil survey handbook, title 430-VI. http://www.nrcs.usda.gov/wps/portal/ nrcs/detail/soils/scientists/?cid=nrcs142p2_054242 United States Department of Agriculture, Natural Resources Conservation Service. 2006. Land resource regions and major land resource areas of the United States, the Caribbean, and the Pacific Basin. U.S. Department of Agriculture Handbook 296. http://www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/? cid=nrcs142p2_053624 United States Department of Agriculture, Soil Conservation Service. 1961. Land capability classification. U.S. Department of Agriculture Handbook 210. http:// www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_052290.pdf Custom Soil Resource Report 21 34 Dewey Court Northampton, Massachusetts Stormwater Management Report The Berkshire Design Group, Inc. Appendix B – Test Pit Results Plantings O O O O X X X X X X X X X X X X X X MH MH W/ F S h e d 1 Story Wood Frame Garage 1 Story W/F Garage 1 StyDeck Treeline Treeline Woods Woods Path Pa t h o o o oo 23" 28" 28" 28" (Dead)20" 32" 20" 20" 22" 31" 21" 27" 22" 35" 46" 8" (Dead) 12" 12" (Dead) P l a n t i n g s Plantings Lawn Plantings 39" 35" Shrub Shrubs 28" 22" 39" 48" 27" 21" 27" 27" Treeline 28" 27"20" 22" 22" 33" 22" 26" 41" 32" 30" 24" 25" 22" 20" #34 2 Story W/F House 1 S t o r y 1 Sty 1 Sty 1 Sty 10" 46" Lawn Bitumino u s D r i v e Plan t i n g s Plantings Rim:133.44' Sump:131.4' CB Rim:133.57' Sump:131.4' Bituminous Drive Shrubs/ Plantings B i t . C u r b B i t u m i n o u s W a l k W.V. SMH(Record) Rim:133.80' Not Opened(Car Over) Record Invert= -5.73' Bituminous Drive 4"PVC Invert Out: 118.88' Stone Retaining Walls Concrete Walk Overhang R.D. R.D. R.D. R.D. Guy Wire UP 03 FF(Thresh) El:133.80' FF(Thresh) El:135.99' FF(Thresh) El:128.54' Plantings Brick & Stone Porch w/ Canopy St o n e W a l k Stone Patio/ Brick & Stone Steps Wooden Stairs Concrete Walk & Curb Chimney 13 4 13 2 13 3 131 13 0 128 129 131 131 131 130 129 128 127 126125 1 2 1 1 2 2 123 124 1 2 0 11 9 118 117 1 3 4 13 3 134 1 3 5 135 1 3 4 134 133 132 13 1 13 3 132 1 3 0 13 1 125 120 11 8 129 13 3 132 131 130 129 128 13 4 13 0 12 5 120 118 119 Lawn St o n e C u r b S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S MH Rim:127.57' Record Sewer Line S W W W W TBM= Top Spindle Of Hydrant El:136.12' D 4" Water R e c o r d S e w e r L i n e 8 " V C 1 2 2 . 1 ' 8 " V C 1 2 2 . 0 ' Bit . C u r b 10" A C 131 . 4 ' WF A1WF A2 WF A3 WF A4 WF A5 WF A6 WF A7 WF A8 WF A1 WF A9 WF A10 WF A11 WF A12 WF A13 WF A16 WF B1 WF B2 WF B3 WF B4 WF B5 WF B6 WF B7 WF B8 Flagged Wetlands Flagged Wetlands TP-1 TP-2 TP-3 Checked By: Drawn By: Revisions Scale: Date:Sheet Number This drawing is not intended nor shall it be used for construction purposes unless the signed professional seal of a registered landscape architect, civil engineer or land surveyor employed by The Berkshire Design Group, Inc. is affixed above. Web: http://www.berkshiredesign.com Email: bdg@berkshiredesign.com (413) 582-7000 4 Allen Place, Northampton, Massachusetts 01060 FAX (413) 582-7005 Landscape Architecture Civil Engineering Planning Berkshire Group Design Do not scale drawing for quantity take-offs or construction. Use written dimensions only. If dimensions are incomplete, contact The Berkshire Design Group Inc. for clarification. Land Surveying Copyright The Berkshire Design Group, Inc. This drawing and all of its contents are the express property of The Berkshire Design Group, Inc., and shall not be copied or used in any way without the written consent of The BerkshireDesign Group, Inc. c 34 DEWEY COURT NORTHAMPTON, MASSACHUSETTS TP APRIL 16, 2019 1"=30' CC XXX TEST PIT LOCATION PLAN 0 603015 90 Note: This soil evaluation has been performed for the purpose of stormwater management design, and shall not be used for purposes related to Title 5 and/or soil suitability assessments for on-site sewage disposal. 4 Allen Place, Northampton, MA 01060 (413) 582-7000 bdg@berkshiredesign.com Berkshire Design Group Soil Evaluation Location Address or Lot No. 34 Dewey Court, Northampton, MA Performed By Chris Chamberland, P.E. Deep Hole Number TP1 Date 4/18/19 Time 8:30 am Weather Sunny, 40°F Location Description (See Plan) Lawn at southeast corner of site Land Use Lawn Slope (%) 0-2 Surface Elevation at Hole 130.5 Vegetation Grass/Moss Surface Stones --- Soil Parent Material Glacial Outwash Landform Terrace Position on Landscape (SU, SH, BS, FS, TS) SU Distances from: Open Water Body --- Feet Drainage way 60 Feet Wetlands 60 Feet Property Line 40 Feet Drinking Water Well --- Feet Other --- Unsuitable Materials Present: ☐ Yes ☒ No If Yes: ☐ Disturbed Soil/Fill ☐ Weathered/Fractured Rock ☐Bedrock Soil Log Depth (in) Soil Horizon Soil Texture (USDA) Soil Color (Munsell) Soil Mottling Coarse Fragments % by Volume Soil Structure Soil Consistence Other Depth Color % Gravel Cobbles & Stones 0-3 Ap Silt Loam 10 YR 2/1 --- --- Massive Firm * 3-18 1C1 Silt Loam 10 YR 3/1 --- --- Massive Firm * 18-36 2C1 Medium Sand 10 YR 3/3 36? Unclear --- --- Single Grain Loose 36-78 2C2 Coarse Sand & Gravel 7.5 YR 2.5/3 30 10 Single Grain Loose Additional Notes: *Minimal true topsoil. No weathering “B” layer. Possible artificial fill Possible mottling at 36” but not very distinct vs soil color. Depth to Groundwater Weeping from Pit Face 36 Standing Water 42 Mottling 36? (Unclear ESHGW Depth 36 ESHGW Elev. 127.5 Frimpter? ☐ Yes (Attach Sheet) ☒ No Note: This soil evaluation has been performed for the purpose of stormwater management design, and shall not be used for purposes related to Title 5 and/or soil suitability assessments for on-site sewage disposal. 4 Allen Place, Northampton, MA 01060 (413) 582-7000 bdg@berkshiredesign.com Berkshire Design Group Soil Evaluation Location Address or Lot No. 34 Dewey Court, Northampton, MA Performed By Chris Chamberland, P.E. Deep Hole Number TP2 Date 4/18/19 Time 9:15 am Weather Sunny, 40°F Location Description (See Plan) Lawn at east-center of site Land Use Lawn Slope (%) 2-5 Surface Elevation at Hole 130.5 Vegetation Grass Surface Stones --- Soil Parent Material Glacial Outwash Landform Terrace Position on Landscape (SU, SH, BS, FS, TS) SU Distances from: Open Water Body --- Feet Drainage way 75 Feet Wetlands 75 Feet Property Line 75 Feet Drinking Water Well --- Feet Other --- Unsuitable Materials Present: ☐ Yes ☒ No If Yes: ☐ Disturbed Soil/Fill ☐ Weathered/Fractured Rock ☐Bedrock Soil Log Depth (in) Soil Horizon Soil Texture (USDA) Soil Color (Munsell) Soil Mottling Coarse Fragments % by Volume Soil Structure Soil Consistence Other Depth Color % Gravel Cobbles & Stones 0-6 Ap Silt Loam 10 YR 2/1 --- --- Massive Very Friable 6-20 1C1 Silt Loam 10 YR 3/1 --- --- Massive Very Friable 20-38 2C1 Medium Sand 10 YR 4/2 30 7.5 YR 5/8 40 --- --- Single Grain Loose 38-40 2C2 Loamy Sand 10 YR 3/1 10 2 Massive Friable 40-84 2C3 Coarse Sand & Gravel 10 YR 4/3 30 10 Single Grain Loose Additional Notes: Very bright mottling line. Depth to Groundwater Weeping from Pit Face 66 Standing Water 72 Mottling 30 ESHGW Depth 30 ESHGW Elev. 127.5 Frimpter? ☐ Yes (Attach Sheet) ☒ No Note: This soil evaluation has been performed for the purpose of stormwater management design, and shall not be used for purposes related to Title 5 and/or soil suitability assessments for on-site sewage disposal. 4 Allen Place, Northampton, MA 01060 (413) 582-7000 bdg@berkshiredesign.com Berkshire Design Group Soil Evaluation Location Address or Lot No. 34 Dewey Court, Northampton, MA Performed By Chris Chamberland, P.E. Deep Hole Number TP3 Date 4/18/19 Time 9:45 am Weather Sunny, 40°F Location Description (See Plan) Lawn at west-center of site Land Use Lawn Slope (%) 0-2 Surface Elevation at Hole 131 Vegetation Grass Surface Stones --- Soil Parent Material Glacial Outwash Landform Terrace Position on Landscape (SU, SH, BS, FS, TS) SU Distances from: Open Water Body --- Feet Drainage way 130 Feet Wetlands 130 Feet Property Line 55 Feet Drinking Water Well --- Feet Other --- Unsuitable Materials Present: ☐ Yes ☒ No If Yes: ☐ Disturbed Soil/Fill ☐ Weathered/Fractured Rock ☐Bedrock Soil Log Depth (in) Soil Horizon Soil Texture (USDA) Soil Color (Munsell) Soil Mottling Coarse Fragments % by Volume Soil Structure Soil Consistence Other Depth Color % Gravel Cobbles & Stones Additional Notes: Mixed sandy & silty layers from 0-48 inches. Heavy weeping at 36” from south face of pit. Depth to Groundwater Weeping from Pit Face 36 Standing Water 48 Mottling --- ESHGW Depth 30 ESHGW Elev. 128.5 Frimpter? ☐ Yes (Attach Sheet) ☒ No 34 Dewey Court Northampton, Massachusetts Stormwater Management Report The Berkshire Design Group, Inc. Appendix C – Stormwater Hydrology Calculations E1 Existing conditions P1a Covered South Pkg Roof + 24 Dewey P1b Dewey Ct + top of circle P2 South Pkg lot - South end P3 south pkg lot +entranceP4 Roof runoff - Front P5 South patios, middle roof and rain garden P6 Walkway / South Roof runoff and all remaining lands P7 Covered Parking Roof - North P8 North Pkg lot CP - Pre Property Line - NE side CP Post Prop line - NE side 1P Sub-surface detention and infiltration #1 - ACF R Tank 2P Sub-surface detention #2 - ACF R Tank RG1 rain garden #1 RG2 rain garden #2 RG3 rain garden #3 RG4 rain garden #4 Routing Diagram for 19.008 - Model 070819 Prepared by Berkshire Design Group, Printed 7/8/2019 HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Subcat Reach Pond Link 19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 2HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Area Listing (all nodes) Area (acres) CN Description (subcatchment-numbers) 1.911 61 >75% Grass cover, Good, HSG B (E1, P1a, P1b, P2, P3, P5, P6, P7, P8) 0.831 98 Paved parking, HSG B (E1, P1a, P1b, P2, P3, P4, P5, P6, P7, P8) 2.742 72 TOTAL AREA NRCC 24-hr C 2-Year Rainfall=3.07"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 3HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Subcatchment E1: Existing conditions Runoff = 0.78 cfs @ 12.19 hrs, Volume= 0.071 af, Depth= 0.62" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs NRCC 24-hr C 2-Year Rainfall=3.07" Area (sf) CN Description 9,140 98 Paved parking, HSG B 50,584 61 >75% Grass cover, Good, HSG B 59,724 67 Weighted Average 50,584 84.70% Pervious Area 9,140 15.30% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, Subcatchment E1: Existing conditions Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 0.85 0.8 0.75 0.7 0.65 0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 NRCC 24-hr C 2-Year Rainfall=3.07" Runoff Area=59,724 sf Runoff Volume=0.071 af Runoff Depth=0.62" Tc=10.0 min CN=67 0.78 cfs NRCC 24-hr C 2-Year Rainfall=3.07"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 4HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Subcatchment P1a: Covered South Pkg Roof + 24 Dewey Runoff = 0.29 cfs @ 12.13 hrs, Volume= 0.018 af, Depth= 1.43" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs NRCC 24-hr C 2-Year Rainfall=3.07" Area (sf) CN Description 3,745 98 Paved parking, HSG B 2,762 61 >75% Grass cover, Good, HSG B 6,507 82 Weighted Average 2,762 42.45% Pervious Area 3,745 57.55% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment P1a: Covered South Pkg Roof + 24 Dewey Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 0.3 0.28 0.26 0.24 0.22 0.2 0.18 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 NRCC 24-hr C 2-Year Rainfall=3.07" Runoff Area=6,507 sf Runoff Volume=0.018 af Runoff Depth=1.43" Tc=5.0 min CN=82 0.29 cfs NRCC 24-hr C 2-Year Rainfall=3.07"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 5HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Subcatchment P1b: Dewey Ct + top of circle Runoff = 0.15 cfs @ 12.12 hrs, Volume= 0.009 af, Depth= 1.80" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs NRCC 24-hr C 2-Year Rainfall=3.07" Area (sf) CN Description 1,898 98 Paved parking, HSG B 843 61 >75% Grass cover, Good, HSG B 2,741 87 Weighted Average 843 30.76% Pervious Area 1,898 69.24% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment P1b: Dewey Ct + top of circle Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 0.16 0.15 0.14 0.13 0.12 0.11 0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 NRCC 24-hr C 2-Year Rainfall=3.07" Runoff Area=2,741 sf Runoff Volume=0.009 af Runoff Depth=1.80" Tc=5.0 min CN=87 0.15 cfs NRCC 24-hr C 2-Year Rainfall=3.07"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 6HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Subcatchment P2: South Pkg lot - South end Runoff = 0.14 cfs @ 12.12 hrs, Volume= 0.009 af, Depth= 2.05" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs NRCC 24-hr C 2-Year Rainfall=3.07" Area (sf) CN Description 1,808 98 Paved parking, HSG B 535 61 >75% Grass cover, Good, HSG B 2,343 90 Weighted Average 535 22.83% Pervious Area 1,808 77.17% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment P2: South Pkg lot - South end Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 0.15 0.14 0.13 0.12 0.11 0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 NRCC 24-hr C 2-Year Rainfall=3.07" Runoff Area=2,343 sf Runoff Volume=0.009 af Runoff Depth=2.05" Tc=5.0 min CN=90 0.14 cfs NRCC 24-hr C 2-Year Rainfall=3.07"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 7HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Subcatchment P3: south pkg lot +entrance Runoff = 0.18 cfs @ 12.12 hrs, Volume= 0.013 af, Depth= 2.62" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs NRCC 24-hr C 2-Year Rainfall=3.07" Area (sf) CN Description 2,355 98 Paved parking, HSG B 144 61 >75% Grass cover, Good, HSG B 2,499 96 Weighted Average 144 5.76% Pervious Area 2,355 94.24% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment P3: south pkg lot +entrance Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 0.2 0.19 0.18 0.17 0.16 0.15 0.14 0.13 0.12 0.11 0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 NRCC 24-hr C 2-Year Rainfall=3.07" Runoff Area=2,499 sf Runoff Volume=0.013 af Runoff Depth=2.62" Tc=5.0 min CN=96 0.18 cfs NRCC 24-hr C 2-Year Rainfall=3.07"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 8HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Subcatchment P4: Roof runoff - Front Runoff = 0.28 cfs @ 12.12 hrs, Volume= 0.021 af, Depth= 2.84" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs NRCC 24-hr C 2-Year Rainfall=3.07" Area (sf) CN Description 3,785 98 Paved parking, HSG B 3,785 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment P4: Roof runoff - Front Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 0.3 0.28 0.26 0.24 0.22 0.2 0.18 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 NRCC 24-hr C 2-Year Rainfall=3.07" Runoff Area=3,785 sf Runoff Volume=0.021 af Runoff Depth=2.84" Tc=5.0 min CN=98 0.28 cfs NRCC 24-hr C 2-Year Rainfall=3.07"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 9HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Subcatchment P5: South patios, middle roof and rain garden Runoff = 0.06 cfs @ 12.13 hrs, Volume= 0.004 af, Depth= 1.24" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs NRCC 24-hr C 2-Year Rainfall=3.07" Area (sf) CN Description 721 98 Paved parking, HSG B 782 61 >75% Grass cover, Good, HSG B 1,503 79 Weighted Average 782 52.03% Pervious Area 721 47.97% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment P5: South patios, middle roof and rain garden Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 0.06 0.055 0.05 0.045 0.04 0.035 0.03 0.025 0.02 0.015 0.01 0.005 0 NRCC 24-hr C 2-Year Rainfall=3.07" Runoff Area=1,503 sf Runoff Volume=0.004 af Runoff Depth=1.24" Tc=5.0 min CN=79 0.06 cfs NRCC 24-hr C 2-Year Rainfall=3.07"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 10HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Subcatchment P6: Walkway / South Roof runoff and all remaining lands Runoff = 0.63 cfs @ 12.13 hrs, Volume= 0.043 af, Depth= 0.71" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs NRCC 24-hr C 2-Year Rainfall=3.07" Area (sf) CN Description 6,904 98 Paved parking, HSG B 24,711 61 >75% Grass cover, Good, HSG B 31,615 69 Weighted Average 24,711 78.16% Pervious Area 6,904 21.84% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment P6: Walkway / South Roof runoff and all remaining lands Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 0.7 0.65 0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 NRCC 24-hr C 2-Year Rainfall=3.07" Runoff Area=31,615 sf Runoff Volume=0.043 af Runoff Depth=0.71" Tc=5.0 min CN=69 0.63 cfs NRCC 24-hr C 2-Year Rainfall=3.07"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 11HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Subcatchment P7: Covered Parking Roof - North Runoff = 0.13 cfs @ 12.13 hrs, Volume= 0.008 af, Depth= 1.12" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs NRCC 24-hr C 2-Year Rainfall=3.07" Area (sf) CN Description 1,723 98 Paved parking, HSG B 2,203 61 >75% Grass cover, Good, HSG B 3,926 77 Weighted Average 2,203 56.11% Pervious Area 1,723 43.89% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment P7: Covered Parking Roof - North Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 0.14 0.13 0.12 0.11 0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 NRCC 24-hr C 2-Year Rainfall=3.07" Runoff Area=3,926 sf Runoff Volume=0.008 af Runoff Depth=1.12" Tc=5.0 min CN=77 0.13 cfs NRCC 24-hr C 2-Year Rainfall=3.07"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 12HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Subcatchment P8: North Pkg lot Runoff = 0.32 cfs @ 12.12 hrs, Volume= 0.021 af, Depth= 2.32" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs NRCC 24-hr C 2-Year Rainfall=3.07" Area (sf) CN Description 4,111 98 Paved parking, HSG B 694 61 >75% Grass cover, Good, HSG B 4,805 93 Weighted Average 694 14.44% Pervious Area 4,111 85.56% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment P8: North Pkg lot Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 0.36 0.34 0.32 0.3 0.28 0.26 0.24 0.22 0.2 0.18 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 NRCC 24-hr C 2-Year Rainfall=3.07" Runoff Area=4,805 sf Runoff Volume=0.021 af Runoff Depth=2.32" Tc=5.0 min CN=93 0.32 cfs NRCC 24-hr C 2-Year Rainfall=3.07"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 13HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Reach CP - Pre: Property Line - NE side Inflow Area = 1.371 ac, 15.30% Impervious, Inflow Depth = 0.62" for 2-Year event Inflow = 0.78 cfs @ 12.19 hrs, Volume= 0.071 af Outflow = 0.78 cfs @ 12.19 hrs, Volume= 0.071 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs Reach CP - Pre: Property Line - NE side Inflow Outflow Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 0.85 0.8 0.75 0.7 0.65 0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 Inflow Area=1.371 ac 0.78 cfs0.78 cfs NRCC 24-hr C 2-Year Rainfall=3.07"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 14HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Reach CP Post: Prop line - NE side Inflow Area = 1.371 ac, 45.29% Impervious, Inflow Depth = 0.57" for 2-Year event Inflow = 0.78 cfs @ 12.13 hrs, Volume= 0.065 af Outflow = 0.78 cfs @ 12.13 hrs, Volume= 0.065 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs Reach CP Post: Prop line - NE side Inflow Outflow Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 0.85 0.8 0.75 0.7 0.65 0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 Inflow Area=1.371 ac 0.78 cfs0.78 cfs NRCC 24-hr C 2-Year Rainfall=3.07"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 15HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Pond 1P: Sub-surface detention and infiltration #1 - ACF R Tank Inflow Area = 0.410 ac, 76.03% Impervious, Inflow Depth = 1.70" for 2-Year event Inflow = 1.01 cfs @ 12.13 hrs, Volume= 0.058 af Outflow = 0.08 cfs @ 11.59 hrs, Volume= 0.058 af, Atten= 93%, Lag= 0.0 min Discarded = 0.08 cfs @ 11.59 hrs, Volume= 0.058 af Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs / 2 Peak Elev= 130.97' @ 13.20 hrs Surf.Area= 3,242 sf Storage= 949 cf Plug-Flow detention time= 96.1 min calculated for 0.058 af (100% of inflow) Center-of-Mass det. time= 96.1 min ( 886.2 - 790.1 ) Volume Invert Avail.Storage Storage Description #1A 130.50' 1,770 cf 82.74'W x 39.19'L x 2.04'H Field A 6,606 cf Overall - 2,182 cf Embedded = 4,424 cf x 40.0% Voids #2A 130.75' 2,073 cf ACF R-Tank HD 0.5 x 900 Inside #1 Inside= 15.7"W x 9.4"H => 0.98 sf x 2.35'L = 2.3 cf Outside= 15.7"W x 9.4"H => 1.03 sf x 2.35'L = 2.4 cf 900 Chambers in 60 Rows 3,842 cf Total Available Storage Storage Group A created with Chamber Wizard Device Routing Invert Outlet Devices #1 Primary 130.75'8.0" Round Culvert L= 10.0' RCP, rounded edge headwall, Ke= 0.100 Inlet / Outlet Invert= 130.75' / 130.65' S= 0.0100 '/' Cc= 0.900 n= 0.012, Flow Area= 0.35 sf #2 Device 1 131.90'8.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads #3 Discarded 130.50'1.000 in/hr Exfiltration over Surface area Phase-In= 0.02' Discarded OutFlow Max=0.08 cfs @ 11.59 hrs HW=130.52' (Free Discharge) 3=Exfiltration (Exfiltration Controls 0.08 cfs) Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=130.50' (Free Discharge) 1=Culvert ( Controls 0.00 cfs) 2=Orifice/Grate ( Controls 0.00 cfs) NRCC 24-hr C 2-Year Rainfall=3.07"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 16HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Pond 1P: Sub-surface detention and infiltration #1 - ACF R Tank Inflow Outflow Discarded Primary Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 1 0 Inflow Area=0.410 ac Peak Elev=130.97' Storage=949 cf 1.01 cfs 0.08 cfs0.08 cfs 0.00 cfs NRCC 24-hr C 2-Year Rainfall=3.07"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 17HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Pond 2P: Sub-surface detention #2 - ACF R Tank Inflow Area = 0.200 ac, 66.82% Impervious, Inflow Depth = 1.35" for 2-Year event Inflow = 0.32 cfs @ 12.12 hrs, Volume= 0.022 af Outflow = 0.17 cfs @ 12.20 hrs, Volume= 0.022 af, Atten= 48%, Lag= 4.5 min Primary = 0.17 cfs @ 12.20 hrs, Volume= 0.022 af Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs / 2 Peak Elev= 129.13' @ 12.20 hrs Surf.Area= 330 sf Storage= 123 cf Plug-Flow detention time= 12.3 min calculated for 0.022 af (100% of inflow) Center-of-Mass det. time= 12.3 min ( 810.9 - 798.6 ) Volume Invert Avail.Storage Storage Description #1A 128.50' 315 cf 14.50'W x 22.77'L x 4.07'H Field A 1,344 cf Overall - 556 cf Embedded = 788 cf x 40.0% Voids #2A 128.75' 528 cf ACF R-Tank HD 2 x 64 Inside #1 Inside= 15.7"W x 33.9"H => 3.52 sf x 2.35'L = 8.3 cf Outside= 15.7"W x 33.9"H => 3.70 sf x 2.35'L = 8.7 cf 64 Chambers in 8 Rows 843 cf Total Available Storage Storage Group A created with Chamber Wizard Device Routing Invert Outlet Devices #1 Primary 128.50'8.0" Round Culvert L= 10.0' RCP, rounded edge headwall, Ke= 0.100 Inlet / Outlet Invert= 128.50' / 128.40' S= 0.0100 '/' Cc= 0.900 n= 0.012, Flow Area= 0.35 sf #2 Device 1 128.50'3.0" Vert. Orifice/Grate C= 0.600 #3 Device 1 131.75'8.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads Primary OutFlow Max=0.17 cfs @ 12.20 hrs HW=129.13' (Free Discharge) 1=Culvert (Passes 0.17 cfs of 0.88 cfs potential flow) 2=Orifice/Grate (Orifice Controls 0.17 cfs @ 3.41 fps) 3=Orifice/Grate ( Controls 0.00 cfs) NRCC 24-hr C 2-Year Rainfall=3.07"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 18HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Pond 2P: Sub-surface detention #2 - ACF R Tank Inflow Primary Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 0.36 0.34 0.32 0.3 0.28 0.26 0.24 0.22 0.2 0.18 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 Inflow Area=0.200 ac Peak Elev=129.13' Storage=123 cf 0.32 cfs 0.17 cfs NRCC 24-hr C 2-Year Rainfall=3.07"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 19HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Pond RG1: rain garden #1 Inflow Area = 0.063 ac, 69.24% Impervious, Inflow Depth = 1.80" for 2-Year event Inflow = 0.15 cfs @ 12.12 hrs, Volume= 0.009 af Outflow = 0.14 cfs @ 12.14 hrs, Volume= 0.009 af, Atten= 4%, Lag= 0.9 min Discarded = 0.00 cfs @ 12.14 hrs, Volume= 0.006 af Primary = 0.14 cfs @ 12.14 hrs, Volume= 0.004 af Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs / 2 Peak Elev= 132.77' @ 12.14 hrs Surf.Area= 168 sf Storage= 96 cf Plug-Flow detention time= 165.1 min calculated for 0.009 af (100% of inflow) Center-of-Mass det. time= 162.2 min ( 990.9 - 828.7 ) Volume Invert Avail.Storage Storage Description #1 132.00' 137 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 132.00 80 0 0 133.00 193 137 137 Device Routing Invert Outlet Devices #1 Discarded 132.00'1.020 in/hr Exfiltration over Surface area Phase-In= 0.02' #2 Primary 132.70'8.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads Discarded OutFlow Max=0.00 cfs @ 12.14 hrs HW=132.77' (Free Discharge) 1=Exfiltration (Exfiltration Controls 0.00 cfs) Primary OutFlow Max=0.14 cfs @ 12.14 hrs HW=132.77' (Free Discharge) 2=Orifice/Grate (Weir Controls 0.14 cfs @ 0.89 fps) NRCC 24-hr C 2-Year Rainfall=3.07"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 20HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Pond RG1: rain garden #1 Inflow Outflow Discarded Primary Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 0.16 0.15 0.14 0.13 0.12 0.11 0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 Inflow Area=0.063 ac Peak Elev=132.77' Storage=96 cf 0.15 cfs 0.14 cfs 0.00 cfs 0.14 cfs NRCC 24-hr C 2-Year Rainfall=3.07"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 21HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Pond RG2: rain garden #2 Inflow Area = 0.090 ac, 43.89% Impervious, Inflow Depth = 1.12" for 2-Year event Inflow = 0.13 cfs @ 12.13 hrs, Volume= 0.008 af Outflow = 0.02 cfs @ 12.57 hrs, Volume= 0.008 af, Atten= 82%, Lag= 26.7 min Discarded = 0.01 cfs @ 12.57 hrs, Volume= 0.007 af Primary = 0.02 cfs @ 12.57 hrs, Volume= 0.001 af Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs Peak Elev= 133.52' @ 12.57 hrs Surf.Area= 255 sf Storage= 136 cf Plug-Flow detention time= 238.1 min calculated for 0.008 af (100% of inflow) Center-of-Mass det. time= 238.1 min ( 1,104.2 - 866.1 ) Volume Invert Avail.Storage Storage Description #1 132.80' 280 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 132.80 117 0 0 133.00 163 28 28 134.00 341 252 280 Device Routing Invert Outlet Devices #1 Discarded 132.80'1.020 in/hr Exfiltration over Surface area Phase-In= 0.02' #2 Primary 133.50'8.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads Discarded OutFlow Max=0.01 cfs @ 12.57 hrs HW=133.52' (Free Discharge) 1=Exfiltration (Exfiltration Controls 0.01 cfs) Primary OutFlow Max=0.02 cfs @ 12.57 hrs HW=133.52' (Free Discharge) 2=Orifice/Grate (Weir Controls 0.02 cfs @ 0.44 fps) NRCC 24-hr C 2-Year Rainfall=3.07"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 22HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Pond RG2: rain garden #2 Inflow Outflow Discarded Primary Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 0.14 0.13 0.12 0.11 0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 Inflow Area=0.090 ac Peak Elev=133.52' Storage=136 cf 0.13 cfs 0.02 cfs 0.01 cfs 0.02 cfs NRCC 24-hr C 2-Year Rainfall=3.07"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 23HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Pond RG3: rain garden #3 Inflow Area = 0.054 ac, 77.17% Impervious, Inflow Depth = 2.05" for 2-Year event Inflow = 0.14 cfs @ 12.12 hrs, Volume= 0.009 af Outflow = 0.14 cfs @ 12.14 hrs, Volume= 0.009 af, Atten= 5%, Lag= 1.1 min Discarded = 0.01 cfs @ 12.14 hrs, Volume= 0.006 af Primary = 0.13 cfs @ 12.14 hrs, Volume= 0.003 af Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs Peak Elev= 133.07' @ 12.14 hrs Surf.Area= 214 sf Storage= 90 cf Plug-Flow detention time= 118.7 min calculated for 0.009 af (100% of inflow) Center-of-Mass det. time= 118.7 min ( 933.9 - 815.2 ) Volume Invert Avail.Storage Storage Description #1 132.50' 200 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 132.50 100 0 0 133.00 200 75 75 133.50 300 125 200 Device Routing Invert Outlet Devices #1 Discarded 132.50'1.020 in/hr Exfiltration over Surface area Phase-In= 0.02' #2 Primary 133.00'8.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads Discarded OutFlow Max=0.01 cfs @ 12.14 hrs HW=133.07' (Free Discharge) 1=Exfiltration (Exfiltration Controls 0.01 cfs) Primary OutFlow Max=0.13 cfs @ 12.14 hrs HW=133.07' (Free Discharge) 2=Orifice/Grate (Weir Controls 0.13 cfs @ 0.87 fps) NRCC 24-hr C 2-Year Rainfall=3.07"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 24HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Pond RG3: rain garden #3 Inflow Outflow Discarded Primary Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 0.15 0.14 0.13 0.12 0.11 0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 Inflow Area=0.054 ac Peak Elev=133.07' Storage=90 cf 0.14 cfs 0.14 cfs 0.01 cfs 0.13 cfs NRCC 24-hr C 2-Year Rainfall=3.07"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 25HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Pond RG4: rain garden #4 Inflow Area = 0.035 ac, 47.97% Impervious, Inflow Depth = 1.24" for 2-Year event Inflow = 0.06 cfs @ 12.13 hrs, Volume= 0.004 af Outflow = 0.01 cfs @ 13.10 hrs, Volume= 0.004 af, Atten= 90%, Lag= 58.3 min Discarded = 0.01 cfs @ 13.10 hrs, Volume= 0.004 af Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs Peak Elev= 131.46' @ 13.10 hrs Surf.Area= 241 sf Storage= 54 cf Plug-Flow detention time= 87.5 min calculated for 0.004 af (100% of inflow) Center-of-Mass det. time= 87.5 min ( 946.4 - 859.0 ) Volume Invert Avail.Storage Storage Description #1 131.20' 220 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 131.20 176 0 0 132.00 375 220 220 Device Routing Invert Outlet Devices #1 Primary 131.75'5.0' long x 3.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 Coef. (English) 2.44 2.58 2.68 2.67 2.65 2.64 2.64 2.68 2.68 2.72 2.81 2.92 2.97 3.07 3.32 #2 Discarded 131.20'1.020 in/hr Exfiltration over Surface area Phase-In= 0.02' Discarded OutFlow Max=0.01 cfs @ 13.10 hrs HW=131.46' (Free Discharge) 2=Exfiltration (Exfiltration Controls 0.01 cfs) Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=131.20' (Free Discharge) 1=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) NRCC 24-hr C 2-Year Rainfall=3.07"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 26HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Pond RG4: rain garden #4 Inflow Outflow Discarded Primary Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 0.06 0.055 0.05 0.045 0.04 0.035 0.03 0.025 0.02 0.015 0.01 0.005 0 Inflow Area=0.035 ac Peak Elev=131.46' Storage=54 cf 0.06 cfs 0.01 cfs0.01 cfs 0.00 cfs NRCC 24-hr C 10-Year Rainfall=4.47"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 27HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Subcatchment E1: Existing conditions Runoff = 2.06 cfs @ 12.18 hrs, Volume= 0.165 af, Depth= 1.44" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs NRCC 24-hr C 10-Year Rainfall=4.47" Area (sf) CN Description 9,140 98 Paved parking, HSG B 50,584 61 >75% Grass cover, Good, HSG B 59,724 67 Weighted Average 50,584 84.70% Pervious Area 9,140 15.30% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, Subcatchment E1: Existing conditions Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 2 1 0 NRCC 24-hr C 10-Year Rainfall=4.47" Runoff Area=59,724 sf Runoff Volume=0.165 af Runoff Depth=1.44" Tc=10.0 min CN=67 2.06 cfs NRCC 24-hr C 10-Year Rainfall=4.47"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 28HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Subcatchment P1a: Covered South Pkg Roof + 24 Dewey Runoff = 0.51 cfs @ 12.12 hrs, Volume= 0.032 af, Depth= 2.61" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs NRCC 24-hr C 10-Year Rainfall=4.47" Area (sf) CN Description 3,745 98 Paved parking, HSG B 2,762 61 >75% Grass cover, Good, HSG B 6,507 82 Weighted Average 2,762 42.45% Pervious Area 3,745 57.55% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment P1a: Covered South Pkg Roof + 24 Dewey Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 NRCC 24-hr C 10-Year Rainfall=4.47" Runoff Area=6,507 sf Runoff Volume=0.032 af Runoff Depth=2.61" Tc=5.0 min CN=82 0.51 cfs NRCC 24-hr C 10-Year Rainfall=4.47"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 29HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Subcatchment P1b: Dewey Ct + top of circle Runoff = 0.25 cfs @ 12.12 hrs, Volume= 0.016 af, Depth= 3.07" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs NRCC 24-hr C 10-Year Rainfall=4.47" Area (sf) CN Description 1,898 98 Paved parking, HSG B 843 61 >75% Grass cover, Good, HSG B 2,741 87 Weighted Average 843 30.76% Pervious Area 1,898 69.24% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment P1b: Dewey Ct + top of circle Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 0.26 0.24 0.22 0.2 0.18 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 NRCC 24-hr C 10-Year Rainfall=4.47" Runoff Area=2,741 sf Runoff Volume=0.016 af Runoff Depth=3.07" Tc=5.0 min CN=87 0.25 cfs NRCC 24-hr C 10-Year Rainfall=4.47"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 30HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Subcatchment P2: South Pkg lot - South end Runoff = 0.23 cfs @ 12.12 hrs, Volume= 0.015 af, Depth= 3.37" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs NRCC 24-hr C 10-Year Rainfall=4.47" Area (sf) CN Description 1,808 98 Paved parking, HSG B 535 61 >75% Grass cover, Good, HSG B 2,343 90 Weighted Average 535 22.83% Pervious Area 1,808 77.17% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment P2: South Pkg lot - South end Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 0.25 0.24 0.23 0.22 0.21 0.2 0.19 0.18 0.17 0.16 0.15 0.14 0.13 0.12 0.11 0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 NRCC 24-hr C 10-Year Rainfall=4.47" Runoff Area=2,343 sf Runoff Volume=0.015 af Runoff Depth=3.37" Tc=5.0 min CN=90 0.23 cfs NRCC 24-hr C 10-Year Rainfall=4.47"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 31HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Subcatchment P3: south pkg lot +entrance Runoff = 0.27 cfs @ 12.12 hrs, Volume= 0.019 af, Depth= 4.01" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs NRCC 24-hr C 10-Year Rainfall=4.47" Area (sf) CN Description 2,355 98 Paved parking, HSG B 144 61 >75% Grass cover, Good, HSG B 2,499 96 Weighted Average 144 5.76% Pervious Area 2,355 94.24% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment P3: south pkg lot +entrance Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 0.3 0.28 0.26 0.24 0.22 0.2 0.18 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 NRCC 24-hr C 10-Year Rainfall=4.47" Runoff Area=2,499 sf Runoff Volume=0.019 af Runoff Depth=4.01" Tc=5.0 min CN=96 0.27 cfs NRCC 24-hr C 10-Year Rainfall=4.47"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 32HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Subcatchment P4: Roof runoff - Front Runoff = 0.41 cfs @ 12.12 hrs, Volume= 0.031 af, Depth= 4.23" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs NRCC 24-hr C 10-Year Rainfall=4.47" Area (sf) CN Description 3,785 98 Paved parking, HSG B 3,785 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment P4: Roof runoff - Front Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 0.46 0.44 0.42 0.4 0.38 0.36 0.34 0.32 0.3 0.28 0.26 0.24 0.22 0.2 0.18 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 NRCC 24-hr C 10-Year Rainfall=4.47" Runoff Area=3,785 sf Runoff Volume=0.031 af Runoff Depth=4.23" Tc=5.0 min CN=98 0.41 cfs NRCC 24-hr C 10-Year Rainfall=4.47"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 33HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Subcatchment P5: South patios, middle roof and rain garden Runoff = 0.11 cfs @ 12.12 hrs, Volume= 0.007 af, Depth= 2.35" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs NRCC 24-hr C 10-Year Rainfall=4.47" Area (sf) CN Description 721 98 Paved parking, HSG B 782 61 >75% Grass cover, Good, HSG B 1,503 79 Weighted Average 782 52.03% Pervious Area 721 47.97% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment P5: South patios, middle roof and rain garden Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 0.12 0.115 0.11 0.105 0.1 0.095 0.09 0.085 0.08 0.075 0.07 0.065 0.06 0.055 0.05 0.045 0.04 0.035 0.03 0.025 0.02 0.015 0.01 0.005 0 NRCC 24-hr C 10-Year Rainfall=4.47" Runoff Area=1,503 sf Runoff Volume=0.007 af Runoff Depth=2.35" Tc=5.0 min CN=79 0.11 cfs NRCC 24-hr C 10-Year Rainfall=4.47"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 34HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Subcatchment P6: Walkway / South Roof runoff and all remaining lands Runoff = 1.51 cfs @ 12.13 hrs, Volume= 0.096 af, Depth= 1.58" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs NRCC 24-hr C 10-Year Rainfall=4.47" Area (sf) CN Description 6,904 98 Paved parking, HSG B 24,711 61 >75% Grass cover, Good, HSG B 31,615 69 Weighted Average 24,711 78.16% Pervious Area 6,904 21.84% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment P6: Walkway / South Roof runoff and all remaining lands Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 1 0 NRCC 24-hr C 10-Year Rainfall=4.47" Runoff Area=31,615 sf Runoff Volume=0.096 af Runoff Depth=1.58" Tc=5.0 min CN=69 1.51 cfs NRCC 24-hr C 10-Year Rainfall=4.47"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 35HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Subcatchment P7: Covered Parking Roof - North Runoff = 0.26 cfs @ 12.13 hrs, Volume= 0.016 af, Depth= 2.19" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs NRCC 24-hr C 10-Year Rainfall=4.47" Area (sf) CN Description 1,723 98 Paved parking, HSG B 2,203 61 >75% Grass cover, Good, HSG B 3,926 77 Weighted Average 2,203 56.11% Pervious Area 1,723 43.89% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment P7: Covered Parking Roof - North Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 0.28 0.26 0.24 0.22 0.2 0.18 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 NRCC 24-hr C 10-Year Rainfall=4.47" Runoff Area=3,926 sf Runoff Volume=0.016 af Runoff Depth=2.19" Tc=5.0 min CN=77 0.26 cfs NRCC 24-hr C 10-Year Rainfall=4.47"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 36HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Subcatchment P8: North Pkg lot Runoff = 0.49 cfs @ 12.12 hrs, Volume= 0.034 af, Depth= 3.68" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs NRCC 24-hr C 10-Year Rainfall=4.47" Area (sf) CN Description 4,111 98 Paved parking, HSG B 694 61 >75% Grass cover, Good, HSG B 4,805 93 Weighted Average 694 14.44% Pervious Area 4,111 85.56% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment P8: North Pkg lot Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 NRCC 24-hr C 10-Year Rainfall=4.47" Runoff Area=4,805 sf Runoff Volume=0.034 af Runoff Depth=3.68" Tc=5.0 min CN=93 0.49 cfs NRCC 24-hr C 10-Year Rainfall=4.47"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 37HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Reach CP - Pre: Property Line - NE side Inflow Area = 1.371 ac, 15.30% Impervious, Inflow Depth = 1.44" for 10-Year event Inflow = 2.06 cfs @ 12.18 hrs, Volume= 0.165 af Outflow = 2.06 cfs @ 12.18 hrs, Volume= 0.165 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs Reach CP - Pre: Property Line - NE side Inflow Outflow Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 2 1 0 Inflow Area=1.371 ac 2.06 cfs2.06 cfs NRCC 24-hr C 10-Year Rainfall=4.47"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 38HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Reach CP Post: Prop line - NE side Inflow Area = 1.371 ac, 45.29% Impervious, Inflow Depth = 1.20" for 10-Year event Inflow = 1.73 cfs @ 12.13 hrs, Volume= 0.137 af Outflow = 1.73 cfs @ 12.13 hrs, Volume= 0.137 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs Reach CP Post: Prop line - NE side Inflow Outflow Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 1 0 Inflow Area=1.371 ac 1.73 cfs1.73 cfs NRCC 24-hr C 10-Year Rainfall=4.47"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 39HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Pond 1P: Sub-surface detention and infiltration #1 - ACF R Tank Inflow Area = 0.410 ac, 76.03% Impervious, Inflow Depth = 2.92" for 10-Year event Inflow = 1.64 cfs @ 12.13 hrs, Volume= 0.100 af Outflow = 0.08 cfs @ 11.13 hrs, Volume= 0.100 af, Atten= 95%, Lag= 0.0 min Discarded = 0.08 cfs @ 11.13 hrs, Volume= 0.100 af Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs / 2 Peak Elev= 131.36' @ 13.89 hrs Surf.Area= 3,242 sf Storage= 2,059 cf Plug-Flow detention time= 237.2 min calculated for 0.100 af (100% of inflow) Center-of-Mass det. time= 237.1 min ( 1,018.6 - 781.5 ) Volume Invert Avail.Storage Storage Description #1A 130.50' 1,770 cf 82.74'W x 39.19'L x 2.04'H Field A 6,606 cf Overall - 2,182 cf Embedded = 4,424 cf x 40.0% Voids #2A 130.75' 2,073 cf ACF R-Tank HD 0.5 x 900 Inside #1 Inside= 15.7"W x 9.4"H => 0.98 sf x 2.35'L = 2.3 cf Outside= 15.7"W x 9.4"H => 1.03 sf x 2.35'L = 2.4 cf 900 Chambers in 60 Rows 3,842 cf Total Available Storage Storage Group A created with Chamber Wizard Device Routing Invert Outlet Devices #1 Primary 130.75'8.0" Round Culvert L= 10.0' RCP, rounded edge headwall, Ke= 0.100 Inlet / Outlet Invert= 130.75' / 130.65' S= 0.0100 '/' Cc= 0.900 n= 0.012, Flow Area= 0.35 sf #2 Device 1 131.90'8.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads #3 Discarded 130.50'1.000 in/hr Exfiltration over Surface area Phase-In= 0.02' Discarded OutFlow Max=0.08 cfs @ 11.13 hrs HW=130.52' (Free Discharge) 3=Exfiltration (Exfiltration Controls 0.08 cfs) Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=130.50' (Free Discharge) 1=Culvert ( Controls 0.00 cfs) 2=Orifice/Grate ( Controls 0.00 cfs) NRCC 24-hr C 10-Year Rainfall=4.47"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 40HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Pond 1P: Sub-surface detention and infiltration #1 - ACF R Tank Inflow Outflow Discarded Primary Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 1 0 Inflow Area=0.410 ac Peak Elev=131.36' Storage=2,059 cf 1.64 cfs 0.08 cfs0.08 cfs 0.00 cfs NRCC 24-hr C 10-Year Rainfall=4.47"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 41HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Pond 2P: Sub-surface detention #2 - ACF R Tank Inflow Area = 0.200 ac, 66.82% Impervious, Inflow Depth = 2.47" for 10-Year event Inflow = 0.71 cfs @ 12.13 hrs, Volume= 0.041 af Outflow = 0.27 cfs @ 12.26 hrs, Volume= 0.041 af, Atten= 63%, Lag= 8.0 min Primary = 0.27 cfs @ 12.26 hrs, Volume= 0.041 af Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs / 2 Peak Elev= 129.91' @ 12.26 hrs Surf.Area= 330 sf Storage= 311 cf Plug-Flow detention time= 13.3 min calculated for 0.041 af (100% of inflow) Center-of-Mass det. time= 13.3 min ( 796.8 - 783.4 ) Volume Invert Avail.Storage Storage Description #1A 128.50' 315 cf 14.50'W x 22.77'L x 4.07'H Field A 1,344 cf Overall - 556 cf Embedded = 788 cf x 40.0% Voids #2A 128.75' 528 cf ACF R-Tank HD 2 x 64 Inside #1 Inside= 15.7"W x 33.9"H => 3.52 sf x 2.35'L = 8.3 cf Outside= 15.7"W x 33.9"H => 3.70 sf x 2.35'L = 8.7 cf 64 Chambers in 8 Rows 843 cf Total Available Storage Storage Group A created with Chamber Wizard Device Routing Invert Outlet Devices #1 Primary 128.50'8.0" Round Culvert L= 10.0' RCP, rounded edge headwall, Ke= 0.100 Inlet / Outlet Invert= 128.50' / 128.40' S= 0.0100 '/' Cc= 0.900 n= 0.012, Flow Area= 0.35 sf #2 Device 1 128.50'3.0" Vert. Orifice/Grate C= 0.600 #3 Device 1 131.75'8.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads Primary OutFlow Max=0.27 cfs @ 12.26 hrs HW=129.91' (Free Discharge) 1=Culvert (Passes 0.27 cfs of 2.06 cfs potential flow) 2=Orifice/Grate (Orifice Controls 0.27 cfs @ 5.45 fps) 3=Orifice/Grate ( Controls 0.00 cfs) NRCC 24-hr C 10-Year Rainfall=4.47"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 42HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Pond 2P: Sub-surface detention #2 - ACF R Tank Inflow Primary Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 0.75 0.7 0.65 0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 Inflow Area=0.200 ac Peak Elev=129.91' Storage=311 cf 0.71 cfs 0.27 cfs NRCC 24-hr C 10-Year Rainfall=4.47"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 43HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Pond RG1: rain garden #1 Inflow Area = 0.063 ac, 69.24% Impervious, Inflow Depth = 3.07" for 10-Year event Inflow = 0.25 cfs @ 12.12 hrs, Volume= 0.016 af Outflow = 0.24 cfs @ 12.13 hrs, Volume= 0.016 af, Atten= 2%, Lag= 0.7 min Discarded = 0.00 cfs @ 12.13 hrs, Volume= 0.006 af Primary = 0.24 cfs @ 12.13 hrs, Volume= 0.010 af Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs / 2 Peak Elev= 132.81' @ 12.13 hrs Surf.Area= 171 sf Storage= 101 cf Plug-Flow detention time= 112.3 min calculated for 0.016 af (98% of inflow) Center-of-Mass det. time= 99.2 min ( 911.1 - 811.8 ) Volume Invert Avail.Storage Storage Description #1 132.00' 137 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 132.00 80 0 0 133.00 193 137 137 Device Routing Invert Outlet Devices #1 Discarded 132.00'1.020 in/hr Exfiltration over Surface area Phase-In= 0.02' #2 Primary 132.70'8.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads Discarded OutFlow Max=0.00 cfs @ 12.13 hrs HW=132.81' (Free Discharge) 1=Exfiltration (Exfiltration Controls 0.00 cfs) Primary OutFlow Max=0.24 cfs @ 12.13 hrs HW=132.81' (Free Discharge) 2=Orifice/Grate (Weir Controls 0.24 cfs @ 1.07 fps) NRCC 24-hr C 10-Year Rainfall=4.47"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 44HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Pond RG1: rain garden #1 Inflow Outflow Discarded Primary Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 0.26 0.24 0.22 0.2 0.18 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 Inflow Area=0.063 ac Peak Elev=132.81' Storage=101 cf 0.25 cfs0.24 cfs 0.00 cfs 0.24 cfs NRCC 24-hr C 10-Year Rainfall=4.47"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 45HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Pond RG2: rain garden #2 Inflow Area = 0.090 ac, 43.89% Impervious, Inflow Depth = 2.19" for 10-Year event Inflow = 0.26 cfs @ 12.13 hrs, Volume= 0.016 af Outflow = 0.24 cfs @ 12.15 hrs, Volume= 0.016 af, Atten= 8%, Lag= 1.3 min Discarded = 0.01 cfs @ 12.15 hrs, Volume= 0.009 af Primary = 0.24 cfs @ 12.15 hrs, Volume= 0.007 af Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs Peak Elev= 133.61' @ 12.15 hrs Surf.Area= 271 sf Storage= 159 cf Plug-Flow detention time= 157.5 min calculated for 0.016 af (98% of inflow) Center-of-Mass det. time= 147.7 min ( 992.2 - 844.5 ) Volume Invert Avail.Storage Storage Description #1 132.80' 280 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 132.80 117 0 0 133.00 163 28 28 134.00 341 252 280 Device Routing Invert Outlet Devices #1 Discarded 132.80'1.020 in/hr Exfiltration over Surface area Phase-In= 0.02' #2 Primary 133.50'8.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads Discarded OutFlow Max=0.01 cfs @ 12.15 hrs HW=133.61' (Free Discharge) 1=Exfiltration (Exfiltration Controls 0.01 cfs) Primary OutFlow Max=0.23 cfs @ 12.15 hrs HW=133.61' (Free Discharge) 2=Orifice/Grate (Weir Controls 0.23 cfs @ 1.06 fps) NRCC 24-hr C 10-Year Rainfall=4.47"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 46HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Pond RG2: rain garden #2 Inflow Outflow Discarded Primary Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 0.28 0.26 0.24 0.22 0.2 0.18 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 Inflow Area=0.090 ac Peak Elev=133.61' Storage=159 cf 0.26 cfs 0.24 cfs 0.01 cfs 0.24 cfs NRCC 24-hr C 10-Year Rainfall=4.47"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 47HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Pond RG3: rain garden #3 Inflow Area = 0.054 ac, 77.17% Impervious, Inflow Depth = 3.37" for 10-Year event Inflow = 0.23 cfs @ 12.12 hrs, Volume= 0.015 af Outflow = 0.22 cfs @ 12.14 hrs, Volume= 0.015 af, Atten= 3%, Lag= 0.9 min Discarded = 0.01 cfs @ 12.14 hrs, Volume= 0.007 af Primary = 0.22 cfs @ 12.14 hrs, Volume= 0.008 af Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs Peak Elev= 133.10' @ 12.14 hrs Surf.Area= 220 sf Storage= 96 cf Plug-Flow detention time= 95.3 min calculated for 0.015 af (100% of inflow) Center-of-Mass det. time= 95.4 min ( 895.1 - 799.7 ) Volume Invert Avail.Storage Storage Description #1 132.50' 200 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 132.50 100 0 0 133.00 200 75 75 133.50 300 125 200 Device Routing Invert Outlet Devices #1 Discarded 132.50'1.020 in/hr Exfiltration over Surface area Phase-In= 0.02' #2 Primary 133.00'8.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads Discarded OutFlow Max=0.01 cfs @ 12.14 hrs HW=133.10' (Free Discharge) 1=Exfiltration (Exfiltration Controls 0.01 cfs) Primary OutFlow Max=0.21 cfs @ 12.14 hrs HW=133.10' (Free Discharge) 2=Orifice/Grate (Weir Controls 0.21 cfs @ 1.03 fps) NRCC 24-hr C 10-Year Rainfall=4.47"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 48HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Pond RG3: rain garden #3 Inflow Outflow Discarded Primary Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 0.25 0.24 0.23 0.22 0.21 0.2 0.19 0.18 0.17 0.16 0.15 0.14 0.13 0.12 0.11 0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 Inflow Area=0.054 ac Peak Elev=133.10' Storage=96 cf 0.23 cfs 0.22 cfs 0.01 cfs 0.22 cfs NRCC 24-hr C 10-Year Rainfall=4.47"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 49HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Pond RG4: rain garden #4 Inflow Area = 0.035 ac, 47.97% Impervious, Inflow Depth = 2.35" for 10-Year event Inflow = 0.11 cfs @ 12.12 hrs, Volume= 0.007 af Outflow = 0.01 cfs @ 13.50 hrs, Volume= 0.007 af, Atten= 93%, Lag= 82.4 min Discarded = 0.01 cfs @ 13.50 hrs, Volume= 0.007 af Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs Peak Elev= 131.73' @ 13.50 hrs Surf.Area= 308 sf Storage= 128 cf Plug-Flow detention time= 184.4 min calculated for 0.007 af (100% of inflow) Center-of-Mass det. time= 184.4 min ( 1,022.8 - 838.5 ) Volume Invert Avail.Storage Storage Description #1 131.20' 220 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 131.20 176 0 0 132.00 375 220 220 Device Routing Invert Outlet Devices #1 Primary 131.75'5.0' long x 3.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 Coef. (English) 2.44 2.58 2.68 2.67 2.65 2.64 2.64 2.68 2.68 2.72 2.81 2.92 2.97 3.07 3.32 #2 Discarded 131.20'1.020 in/hr Exfiltration over Surface area Phase-In= 0.02' Discarded OutFlow Max=0.01 cfs @ 13.50 hrs HW=131.73' (Free Discharge) 2=Exfiltration (Exfiltration Controls 0.01 cfs) Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=131.20' (Free Discharge) 1=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) NRCC 24-hr C 10-Year Rainfall=4.47"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 50HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Pond RG4: rain garden #4 Inflow Outflow Discarded Primary Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 0.12 0.115 0.11 0.105 0.1 0.095 0.09 0.085 0.08 0.075 0.07 0.065 0.06 0.055 0.05 0.045 0.04 0.035 0.03 0.025 0.02 0.015 0.01 0.005 0 Inflow Area=0.035 ac Peak Elev=131.73' Storage=128 cf 0.11 cfs 0.01 cfs0.01 cfs 0.00 cfs NRCC 24-hr C 100-Year Rainfall=7.68"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 51HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Subcatchment E1: Existing conditions Runoff = 5.72 cfs @ 12.18 hrs, Volume= 0.441 af, Depth= 3.86" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs NRCC 24-hr C 100-Year Rainfall=7.68" Area (sf) CN Description 9,140 98 Paved parking, HSG B 50,584 61 >75% Grass cover, Good, HSG B 59,724 67 Weighted Average 50,584 84.70% Pervious Area 9,140 15.30% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 10.0 Direct Entry, Subcatchment E1: Existing conditions Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 6 5 4 3 2 1 0 NRCC 24-hr C 100-Year Rainfall=7.68" Runoff Area=59,724 sf Runoff Volume=0.441 af Runoff Depth=3.86" Tc=10.0 min CN=67 5.72 cfs NRCC 24-hr C 100-Year Rainfall=7.68"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 52HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Subcatchment P1a: Covered South Pkg Roof + 24 Dewey Runoff = 1.05 cfs @ 12.12 hrs, Volume= 0.069 af, Depth= 5.56" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs NRCC 24-hr C 100-Year Rainfall=7.68" Area (sf) CN Description 3,745 98 Paved parking, HSG B 2,762 61 >75% Grass cover, Good, HSG B 6,507 82 Weighted Average 2,762 42.45% Pervious Area 3,745 57.55% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment P1a: Covered South Pkg Roof + 24 Dewey Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 1 0 NRCC 24-hr C 100-Year Rainfall=7.68" Runoff Area=6,507 sf Runoff Volume=0.069 af Runoff Depth=5.56" Tc=5.0 min CN=82 1.05 cfs NRCC 24-hr C 100-Year Rainfall=7.68"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 53HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Subcatchment P1b: Dewey Ct + top of circle Runoff = 0.48 cfs @ 12.12 hrs, Volume= 0.032 af, Depth= 6.14" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs NRCC 24-hr C 100-Year Rainfall=7.68" Area (sf) CN Description 1,898 98 Paved parking, HSG B 843 61 >75% Grass cover, Good, HSG B 2,741 87 Weighted Average 843 30.76% Pervious Area 1,898 69.24% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment P1b: Dewey Ct + top of circle Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 0.52 0.5 0.48 0.46 0.44 0.42 0.4 0.38 0.36 0.34 0.32 0.3 0.28 0.26 0.24 0.22 0.2 0.18 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 NRCC 24-hr C 100-Year Rainfall=7.68" Runoff Area=2,741 sf Runoff Volume=0.032 af Runoff Depth=6.14" Tc=5.0 min CN=87 0.48 cfs NRCC 24-hr C 100-Year Rainfall=7.68"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 54HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Subcatchment P2: South Pkg lot - South end Runoff = 0.42 cfs @ 12.12 hrs, Volume= 0.029 af, Depth= 6.49" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs NRCC 24-hr C 100-Year Rainfall=7.68" Area (sf) CN Description 1,808 98 Paved parking, HSG B 535 61 >75% Grass cover, Good, HSG B 2,343 90 Weighted Average 535 22.83% Pervious Area 1,808 77.17% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment P2: South Pkg lot - South end Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 0.46 0.44 0.42 0.4 0.38 0.36 0.34 0.32 0.3 0.28 0.26 0.24 0.22 0.2 0.18 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 NRCC 24-hr C 100-Year Rainfall=7.68" Runoff Area=2,343 sf Runoff Volume=0.029 af Runoff Depth=6.49" Tc=5.0 min CN=90 0.42 cfs NRCC 24-hr C 100-Year Rainfall=7.68"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 55HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Subcatchment P3: south pkg lot +entrance Runoff = 0.47 cfs @ 12.12 hrs, Volume= 0.034 af, Depth= 7.20" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs NRCC 24-hr C 100-Year Rainfall=7.68" Area (sf) CN Description 2,355 98 Paved parking, HSG B 144 61 >75% Grass cover, Good, HSG B 2,499 96 Weighted Average 144 5.76% Pervious Area 2,355 94.24% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment P3: south pkg lot +entrance Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 0.52 0.5 0.48 0.46 0.44 0.42 0.4 0.38 0.36 0.34 0.32 0.3 0.28 0.26 0.24 0.22 0.2 0.18 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 NRCC 24-hr C 100-Year Rainfall=7.68" Runoff Area=2,499 sf Runoff Volume=0.034 af Runoff Depth=7.20" Tc=5.0 min CN=96 0.47 cfs NRCC 24-hr C 100-Year Rainfall=7.68"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 56HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Subcatchment P4: Roof runoff - Front Runoff = 0.71 cfs @ 12.12 hrs, Volume= 0.054 af, Depth= 7.44" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs NRCC 24-hr C 100-Year Rainfall=7.68" Area (sf) CN Description 3,785 98 Paved parking, HSG B 3,785 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment P4: Roof runoff - Front Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 0.75 0.7 0.65 0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 NRCC 24-hr C 100-Year Rainfall=7.68" Runoff Area=3,785 sf Runoff Volume=0.054 af Runoff Depth=7.44" Tc=5.0 min CN=98 0.71 cfs NRCC 24-hr C 100-Year Rainfall=7.68"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 57HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Subcatchment P5: South patios, middle roof and rain garden Runoff = 0.23 cfs @ 12.12 hrs, Volume= 0.015 af, Depth= 5.21" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs NRCC 24-hr C 100-Year Rainfall=7.68" Area (sf) CN Description 721 98 Paved parking, HSG B 782 61 >75% Grass cover, Good, HSG B 1,503 79 Weighted Average 782 52.03% Pervious Area 721 47.97% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment P5: South patios, middle roof and rain garden Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 0.25 0.24 0.23 0.22 0.21 0.2 0.19 0.18 0.17 0.16 0.15 0.14 0.13 0.12 0.11 0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 NRCC 24-hr C 100-Year Rainfall=7.68" Runoff Area=1,503 sf Runoff Volume=0.015 af Runoff Depth=5.21" Tc=5.0 min CN=79 0.23 cfs NRCC 24-hr C 100-Year Rainfall=7.68"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 58HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Subcatchment P6: Walkway / South Roof runoff and all remaining lands Runoff = 3.92 cfs @ 12.12 hrs, Volume= 0.247 af, Depth= 4.08" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs NRCC 24-hr C 100-Year Rainfall=7.68" Area (sf) CN Description 6,904 98 Paved parking, HSG B 24,711 61 >75% Grass cover, Good, HSG B 31,615 69 Weighted Average 24,711 78.16% Pervious Area 6,904 21.84% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment P6: Walkway / South Roof runoff and all remaining lands Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 4 3 2 1 0 NRCC 24-hr C 100-Year Rainfall=7.68" Runoff Area=31,615 sf Runoff Volume=0.247 af Runoff Depth=4.08" Tc=5.0 min CN=69 3.92 cfs NRCC 24-hr C 100-Year Rainfall=7.68"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 59HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Subcatchment P7: Covered Parking Roof - North Runoff = 0.58 cfs @ 12.12 hrs, Volume= 0.037 af, Depth= 4.98" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs NRCC 24-hr C 100-Year Rainfall=7.68" Area (sf) CN Description 1,723 98 Paved parking, HSG B 2,203 61 >75% Grass cover, Good, HSG B 3,926 77 Weighted Average 2,203 56.11% Pervious Area 1,723 43.89% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment P7: Covered Parking Roof - North Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 0.65 0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 NRCC 24-hr C 100-Year Rainfall=7.68" Runoff Area=3,926 sf Runoff Volume=0.037 af Runoff Depth=4.98" Tc=5.0 min CN=77 0.58 cfs NRCC 24-hr C 100-Year Rainfall=7.68"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 60HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Subcatchment P8: North Pkg lot Runoff = 0.88 cfs @ 12.12 hrs, Volume= 0.063 af, Depth= 6.85" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs NRCC 24-hr C 100-Year Rainfall=7.68" Area (sf) CN Description 4,111 98 Paved parking, HSG B 694 61 >75% Grass cover, Good, HSG B 4,805 93 Weighted Average 694 14.44% Pervious Area 4,111 85.56% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment P8: North Pkg lot Runoff Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 0.95 0.9 0.85 0.8 0.75 0.7 0.65 0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 NRCC 24-hr C 100-Year Rainfall=7.68" Runoff Area=4,805 sf Runoff Volume=0.063 af Runoff Depth=6.85" Tc=5.0 min CN=93 0.88 cfs NRCC 24-hr C 100-Year Rainfall=7.68"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 61HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Reach CP - Pre: Property Line - NE side Inflow Area = 1.371 ac, 15.30% Impervious, Inflow Depth = 3.86" for 100-Year event Inflow = 5.72 cfs @ 12.18 hrs, Volume= 0.441 af Outflow = 5.72 cfs @ 12.18 hrs, Volume= 0.441 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs Reach CP - Pre: Property Line - NE side Inflow Outflow Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 6 5 4 3 2 1 0 Inflow Area=1.371 ac 5.72 cfs5.72 cfs NRCC 24-hr C 100-Year Rainfall=7.68"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 62HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Reach CP Post: Prop line - NE side Inflow Area = 1.371 ac, 45.29% Impervious, Inflow Depth = 3.43" for 100-Year event Inflow = 4.52 cfs @ 12.13 hrs, Volume= 0.392 af Outflow = 4.52 cfs @ 12.13 hrs, Volume= 0.392 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs Reach CP Post: Prop line - NE side Inflow Outflow Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 5 4 3 2 1 0 Inflow Area=1.371 ac 4.52 cfs4.52 cfs NRCC 24-hr C 100-Year Rainfall=7.68"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 63HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Pond 1P: Sub-surface detention and infiltration #1 - ACF R Tank Inflow Area = 0.410 ac, 76.03% Impervious, Inflow Depth = 5.92" for 100-Year event Inflow = 3.10 cfs @ 12.12 hrs, Volume= 0.202 af Outflow = 0.94 cfs @ 12.28 hrs, Volume= 0.192 af, Atten= 70%, Lag= 9.6 min Discarded = 0.08 cfs @ 10.02 hrs, Volume= 0.142 af Primary = 0.87 cfs @ 12.28 hrs, Volume= 0.050 af Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs / 2 Peak Elev= 132.17' @ 12.28 hrs Surf.Area= 3,242 sf Storage= 3,363 cf Plug-Flow detention time= 273.9 min calculated for 0.192 af (95% of inflow) Center-of-Mass det. time= 244.1 min ( 1,017.6 - 773.5 ) Volume Invert Avail.Storage Storage Description #1A 130.50' 1,770 cf 82.74'W x 39.19'L x 2.04'H Field A 6,606 cf Overall - 2,182 cf Embedded = 4,424 cf x 40.0% Voids #2A 130.75' 2,073 cf ACF R-Tank HD 0.5 x 900 Inside #1 Inside= 15.7"W x 9.4"H => 0.98 sf x 2.35'L = 2.3 cf Outside= 15.7"W x 9.4"H => 1.03 sf x 2.35'L = 2.4 cf 900 Chambers in 60 Rows 3,842 cf Total Available Storage Storage Group A created with Chamber Wizard Device Routing Invert Outlet Devices #1 Primary 130.75'8.0" Round Culvert L= 10.0' RCP, rounded edge headwall, Ke= 0.100 Inlet / Outlet Invert= 130.75' / 130.65' S= 0.0100 '/' Cc= 0.900 n= 0.012, Flow Area= 0.35 sf #2 Device 1 131.90'8.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads #3 Discarded 130.50'1.000 in/hr Exfiltration over Surface area Phase-In= 0.02' Discarded OutFlow Max=0.08 cfs @ 10.02 hrs HW=130.52' (Free Discharge) 3=Exfiltration (Exfiltration Controls 0.08 cfs) Primary OutFlow Max=0.87 cfs @ 12.28 hrs HW=132.17' (Free Discharge) 1=Culvert (Passes 0.87 cfs of 2.07 cfs potential flow) 2=Orifice/Grate (Orifice Controls 0.87 cfs @ 2.49 fps) NRCC 24-hr C 100-Year Rainfall=7.68"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 64HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Pond 1P: Sub-surface detention and infiltration #1 - ACF R Tank Inflow Outflow Discarded Primary Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 3 2 1 0 Inflow Area=0.410 ac Peak Elev=132.17' Storage=3,363 cf 3.10 cfs 0.94 cfs 0.08 cfs 0.87 cfs NRCC 24-hr C 100-Year Rainfall=7.68"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 65HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Pond 2P: Sub-surface detention #2 - ACF R Tank Inflow Area = 0.200 ac, 66.82% Impervious, Inflow Depth = 5.37" for 100-Year event Inflow = 1.43 cfs @ 12.13 hrs, Volume= 0.090 af Outflow = 1.07 cfs @ 12.17 hrs, Volume= 0.090 af, Atten= 25%, Lag= 2.9 min Primary = 1.07 cfs @ 12.17 hrs, Volume= 0.090 af Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs / 2 Peak Elev= 131.96' @ 12.17 hrs Surf.Area= 330 sf Storage= 762 cf Plug-Flow detention time= 16.1 min calculated for 0.090 af (100% of inflow) Center-of-Mass det. time= 16.2 min ( 793.5 - 777.3 ) Volume Invert Avail.Storage Storage Description #1A 128.50' 315 cf 14.50'W x 22.77'L x 4.07'H Field A 1,344 cf Overall - 556 cf Embedded = 788 cf x 40.0% Voids #2A 128.75' 528 cf ACF R-Tank HD 2 x 64 Inside #1 Inside= 15.7"W x 33.9"H => 3.52 sf x 2.35'L = 8.3 cf Outside= 15.7"W x 33.9"H => 3.70 sf x 2.35'L = 8.7 cf 64 Chambers in 8 Rows 843 cf Total Available Storage Storage Group A created with Chamber Wizard Device Routing Invert Outlet Devices #1 Primary 128.50'8.0" Round Culvert L= 10.0' RCP, rounded edge headwall, Ke= 0.100 Inlet / Outlet Invert= 128.50' / 128.40' S= 0.0100 '/' Cc= 0.900 n= 0.012, Flow Area= 0.35 sf #2 Device 1 128.50'3.0" Vert. Orifice/Grate C= 0.600 #3 Device 1 131.75'8.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads Primary OutFlow Max=1.03 cfs @ 12.17 hrs HW=131.95' (Free Discharge) 1=Culvert (Passes 1.03 cfs of 3.81 cfs potential flow) 2=Orifice/Grate (Orifice Controls 0.43 cfs @ 8.78 fps) 3=Orifice/Grate (Weir Controls 0.60 cfs @ 1.45 fps) NRCC 24-hr C 100-Year Rainfall=7.68"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 66HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Pond 2P: Sub-surface detention #2 - ACF R Tank Inflow Primary Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 1 0 Inflow Area=0.200 ac Peak Elev=131.96' Storage=762 cf 1.43 cfs 1.07 cfs NRCC 24-hr C 100-Year Rainfall=7.68"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 67HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Pond RG1: rain garden #1 Inflow Area = 0.063 ac, 69.24% Impervious, Inflow Depth = 6.14" for 100-Year event Inflow = 0.48 cfs @ 12.12 hrs, Volume= 0.032 af Outflow = 0.47 cfs @ 12.13 hrs, Volume= 0.032 af, Atten= 1%, Lag= 0.6 min Discarded = 0.00 cfs @ 12.13 hrs, Volume= 0.007 af Primary = 0.47 cfs @ 12.13 hrs, Volume= 0.025 af Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs / 2 Peak Elev= 132.87' @ 12.13 hrs Surf.Area= 178 sf Storage= 112 cf Plug-Flow detention time= 64.6 min calculated for 0.032 af (99% of inflow) Center-of-Mass det. time= 56.5 min ( 847.0 - 790.5 ) Volume Invert Avail.Storage Storage Description #1 132.00' 137 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 132.00 80 0 0 133.00 193 137 137 Device Routing Invert Outlet Devices #1 Discarded 132.00'1.020 in/hr Exfiltration over Surface area Phase-In= 0.02' #2 Primary 132.70'8.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads Discarded OutFlow Max=0.00 cfs @ 12.13 hrs HW=132.87' (Free Discharge) 1=Exfiltration (Exfiltration Controls 0.00 cfs) Primary OutFlow Max=0.46 cfs @ 12.13 hrs HW=132.87' (Free Discharge) 2=Orifice/Grate (Weir Controls 0.46 cfs @ 1.33 fps) NRCC 24-hr C 100-Year Rainfall=7.68"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 68HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Pond RG1: rain garden #1 Inflow Outflow Discarded Primary Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 0.52 0.5 0.48 0.46 0.44 0.42 0.4 0.38 0.36 0.34 0.32 0.3 0.28 0.26 0.24 0.22 0.2 0.18 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 Inflow Area=0.063 ac Peak Elev=132.87' Storage=112 cf 0.48 cfs0.47 cfs 0.00 cfs 0.47 cfs NRCC 24-hr C 100-Year Rainfall=7.68"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 69HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Pond RG2: rain garden #2 Inflow Area = 0.090 ac, 43.89% Impervious, Inflow Depth = 4.98" for 100-Year event Inflow = 0.58 cfs @ 12.12 hrs, Volume= 0.037 af Outflow = 0.57 cfs @ 12.14 hrs, Volume= 0.037 af, Atten= 3%, Lag= 0.8 min Discarded = 0.01 cfs @ 12.14 hrs, Volume= 0.010 af Primary = 0.56 cfs @ 12.14 hrs, Volume= 0.027 af Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs Peak Elev= 133.69' @ 12.14 hrs Surf.Area= 286 sf Storage= 182 cf Plug-Flow detention time= 79.5 min calculated for 0.037 af (98% of inflow) Center-of-Mass det. time= 69.3 min ( 887.7 - 818.4 ) Volume Invert Avail.Storage Storage Description #1 132.80' 280 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 132.80 117 0 0 133.00 163 28 28 134.00 341 252 280 Device Routing Invert Outlet Devices #1 Discarded 132.80'1.020 in/hr Exfiltration over Surface area Phase-In= 0.02' #2 Primary 133.50'8.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads Discarded OutFlow Max=0.01 cfs @ 12.14 hrs HW=133.69' (Free Discharge) 1=Exfiltration (Exfiltration Controls 0.01 cfs) Primary OutFlow Max=0.56 cfs @ 12.14 hrs HW=133.69' (Free Discharge) 2=Orifice/Grate (Weir Controls 0.56 cfs @ 1.42 fps) NRCC 24-hr C 100-Year Rainfall=7.68"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 70HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Pond RG2: rain garden #2 Inflow Outflow Discarded Primary Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 0.65 0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 Inflow Area=0.090 ac Peak Elev=133.69' Storage=182 cf 0.58 cfs0.57 cfs 0.01 cfs 0.56 cfs NRCC 24-hr C 100-Year Rainfall=7.68"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 71HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Pond RG3: rain garden #3 Inflow Area = 0.054 ac, 77.17% Impervious, Inflow Depth = 6.49" for 100-Year event Inflow = 0.42 cfs @ 12.12 hrs, Volume= 0.029 af Outflow = 0.41 cfs @ 12.13 hrs, Volume= 0.029 af, Atten= 2%, Lag= 0.8 min Discarded = 0.01 cfs @ 12.13 hrs, Volume= 0.009 af Primary = 0.41 cfs @ 12.13 hrs, Volume= 0.020 af Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs Peak Elev= 133.15' @ 12.13 hrs Surf.Area= 230 sf Storage= 108 cf Plug-Flow detention time= 65.8 min calculated for 0.029 af (100% of inflow) Center-of-Mass det. time= 65.5 min ( 845.8 - 780.3 ) Volume Invert Avail.Storage Storage Description #1 132.50' 200 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 132.50 100 0 0 133.00 200 75 75 133.50 300 125 200 Device Routing Invert Outlet Devices #1 Discarded 132.50'1.020 in/hr Exfiltration over Surface area Phase-In= 0.02' #2 Primary 133.00'8.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads Discarded OutFlow Max=0.01 cfs @ 12.13 hrs HW=133.15' (Free Discharge) 1=Exfiltration (Exfiltration Controls 0.01 cfs) Primary OutFlow Max=0.40 cfs @ 12.13 hrs HW=133.15' (Free Discharge) 2=Orifice/Grate (Weir Controls 0.40 cfs @ 1.27 fps) NRCC 24-hr C 100-Year Rainfall=7.68"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 72HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Pond RG3: rain garden #3 Inflow Outflow Discarded Primary Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 0.46 0.44 0.42 0.4 0.38 0.36 0.34 0.32 0.3 0.28 0.26 0.24 0.22 0.2 0.18 0.16 0.14 0.12 0.1 0.08 0.06 0.04 0.02 0 Inflow Area=0.054 ac Peak Elev=133.15' Storage=108 cf 0.42 cfs0.41 cfs 0.01 cfs 0.41 cfs NRCC 24-hr C 100-Year Rainfall=7.68"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 73HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Summary for Pond RG4: rain garden #4 Inflow Area = 0.035 ac, 47.97% Impervious, Inflow Depth = 5.21" for 100-Year event Inflow = 0.23 cfs @ 12.12 hrs, Volume= 0.015 af Outflow = 0.22 cfs @ 12.14 hrs, Volume= 0.015 af, Atten= 5%, Lag= 1.1 min Discarded = 0.01 cfs @ 12.14 hrs, Volume= 0.010 af Primary = 0.21 cfs @ 12.14 hrs, Volume= 0.005 af Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.01 hrs Peak Elev= 131.82' @ 12.14 hrs Surf.Area= 330 sf Storage= 156 cf Plug-Flow detention time= 136.7 min calculated for 0.015 af (100% of inflow) Center-of-Mass det. time= 136.7 min ( 950.0 - 813.3 ) Volume Invert Avail.Storage Storage Description #1 131.20' 220 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 131.20 176 0 0 132.00 375 220 220 Device Routing Invert Outlet Devices #1 Primary 131.75'5.0' long x 3.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 Coef. (English) 2.44 2.58 2.68 2.67 2.65 2.64 2.64 2.68 2.68 2.72 2.81 2.92 2.97 3.07 3.32 #2 Discarded 131.20'1.020 in/hr Exfiltration over Surface area Phase-In= 0.02' Discarded OutFlow Max=0.01 cfs @ 12.14 hrs HW=131.82' (Free Discharge) 2=Exfiltration (Exfiltration Controls 0.01 cfs) Primary OutFlow Max=0.21 cfs @ 12.14 hrs HW=131.82' (Free Discharge) 1=Broad-Crested Rectangular Weir (Weir Controls 0.21 cfs @ 0.63 fps) NRCC 24-hr C 100-Year Rainfall=7.68"19.008 - Model 070819 Printed 7/8/2019Prepared by Berkshire Design Group Page 74HydroCAD® 10.00-24 s/n 10759 © 2018 HydroCAD Software Solutions LLC Pond RG4: rain garden #4 Inflow Outflow Discarded Primary Hydrograph Time (hours) 3029282726252423222120191817161514131211109876543210 Fl o w ( c f s ) 0.25 0.24 0.23 0.22 0.21 0.2 0.19 0.18 0.17 0.16 0.15 0.14 0.13 0.12 0.11 0.1 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 Inflow Area=0.035 ac Peak Elev=131.82' Storage=156 cf 0.23 cfs 0.22 cfs 0.01 cfs 0.21 cfs 34 Dewey Court Northampton, Massachusetts Stormwater Management Report The Berkshire Design Group, Inc. Appendix D – Groundwater Recharge Calculations 4 Allen Place, Northampton, MA 01060 (413) 582-7000 bdg@berkshiredesign.com The Berkshire Design Group, Inc. July 7, 2019 Northampton – Dewey Court Stormwater Standard 3 – Recharge Calculations Existing Impervious Area Table 1 shows the existing impervious surface area. Impervious areas include a portion of Dewey Court, the entrance drive, driveway, walkways and garage and existing home rooftops. Table 1. Existing Impervious Area Drainage Area ID (See Figure 5) Impervious Area (sf) E1 9,140 Proposed Impervious Area & Required Recharge Volume Table 2 shows the increase in impervious area and the associated Required Recharge Volume for the overall site. The increase in impervious area is calculated by taking the final impervious area in the proposed condition and subtracting the existing impervious area for the overall site. Required Recharge Volume is calculated by applying the following equation: Required Recharge Volume, = × Where, = Target Depth Factor, 0.35” for HSG B soils = Impervious Area Table 2. Proposed Increase in Impervious Area Drainage Area ID (See Figure 5) Impervious Area (sq. ft.) Increase in Impervious area (sq. ft.) Required Recharge Volume (cu. ft.) P - TOTAL 27,050 17,910 523 Although recharge is only required on the increase in impervious area for the site, multiple practices are proposed for the site resulting in excess recharge capacity. The storage volume provided calculations below, therefore, do not discount for the existing impervious cover. Storage Volume Provided Table 3 summarizes the storage volume provided for the infiltration features in each drainage area taking into account all impervious areas shown on the final plan. For the rain gardens, storage volume was calculated by average end area applied to contours, as shown on the Grading & Drainage Plan. July 7, 2019 Dewey Court - Northampton Stormwater Standard 3 – Recharge Calculations Page 2 of 3 4 Allen Place, Northampton, MA 01060 (413) 582-7000 bdg@berkshiredesign.com Table 3. Proposed Increase in Impervious Area Drainage Area ID (See Figure 6) Site Impervious Area (sq. ft.) Storage Volume Required (cu. ft.) Provided Storage Volume (cu. ft.) P1a 3,745 109 Roof to R-Tank #1 P1b 1,898 55 84 P2 1,808 53 75 P3 2,355 69 3016 P4 3,785 110 Roof to R-Tank #1 P5 721 21 135 P6 6,904 201 Sheet/pipe flow P7 1,723 50 132 P8 4,111 120 Pipe flow Total 27,050 789 3,442 Minimum Storage Volume This analysis utilizes the “Static Method” for determining required storage volume for infiltration features. Therefore, the minimum required storage volume is equal to the Required Recharge Volume, tabulated above. The provided infiltration storage volume of 3,442 cu. ft. exceeds the Required Recharge Volume of 789 cu. ft. (considering all impervious surfaces at the future site). Capture Area Adjustment The Massachusetts Stormwater Handbook requires an increase in storage capacity of infiltration features if only a portion of the site’s impervious area is tributary to the stormwater practices. At the Dewey Court site, a portion of the new building roof and walkway and the existing roof is not captured by a stormwater facility (area P6). In addition, area P8 is tributary to a detention facility which will not provide significant recharge. 1. Required recharge volume (static): 789 cu. ft. (all impervious surfaces) 2. Impervious area draining to recharge facilities: 16,035 sq. ft. 3. Total impervious/impervious draining to facilities: 27,050/16,035 = 1.69 4. 1.69x 789 = 1,331cu. ft. Provided recharge of 3,442 cu. ft. > 1,331 cu. ft. The provided recharge exceeds the required recharge with the capture area adjustment. In addition, the manual requires that 65% of the impervious area drains to recharge facilities. At the Dewey Court project, 59% of the overall impervious area (including existing impervious surfaces) drains to recharge facilities. Because this is a redevelopment, credit is taken for existing untreated July 7, 2019 Dewey Court - Northampton Stormwater Standard 3 – Recharge Calculations Page 3 of 3 4 Allen Place, Northampton, MA 01060 (413) 582-7000 bdg@berkshiredesign.com impervious surfaces. Taking credit for the existing untreated impervious surfaces of 6,400 sq. ft within areas P6 and P8, the percent of impervious area draining to recharge facilities increases to 78% which meets the requirement of 65%. Drawdown Time The Massachusetts Stormwater Handbook requires that infiltration features empty in a time of less than 72 hours. All proposed infiltration features are in areas where soil evaluations have determined that in-situ soils are classified as loamy sand. The Rawls infiltration rate for all infiltration devices is 1.02 inches per hour. 1.02 ℎ × 72ℎ = 73 = 6 All proposed infiltration devices are less than 6 feet deep; therefore, all devices will draw down in less than 72 hours. All infiltration practices drain in less than 72 hours. In addition, the mounding analysis (attached) shows that the maximum groundwater mounding is approximately 5 inches (elevation 128.9). Therefore, the R-tank infiltration system is fully dewatered within 72 hours. 34 D e w e y C o u r t , N o r t h a m p t o n , M A us e c o n s i s t e n t u n i t s ( e . g . f e e t & d a y s or i n c h e s & h o u r s ) Co n v e r s i o n T a b l e In p u t V a l u e s in c h / h o u r f e e t / d a y 2. 0 4 0 0 R Re c h a r g e ( i n f i l t r a t i o n ) r a t e ( f e e t / d a y ) 0.6 7 1.3 3 0. 2 6 0 Sy Sp e c i f i c y i e l d , S y ( d i m e n s i o n l e s s , b e t w e e n 0 a n d 1 ) 20 . 4 0 K Ho r i z o n t a l h y d r a u l i c c o n d u c t i v i t y , K h ( f e e t / d a y ) * 2.0 0 4.0 0 32 . 0 0 0 x 1/ 2 l e n g t h o f b a s i n ( x d i r e c t i o n , i n f e e t ) 20 . 0 0 0 y 1/ 2 w i d t h o f b a s i n ( y d i r e c t i o n , i n f e e t ) ho u r s da y s 0. 0 5 0 t du r a t i o n o f i n f i l t r a t i o n p e r i o d ( d a y s ) 36 1.5 0 4. 5 0 0 hi ( 0 ) in i t i a l t h i c k n e s s o f s a t u r a t e d z o n e ( f e e t ) 4. 8 9 2 h( m a x ) ma x i m u m t h i c k n e s s o f s a t u r a t e d z o n e ( b e n e a t h c e n t e r o f b a s i n a t e n d o f i n f i l t r a t i o n p e r i o d ) 0. 3 9 2 Δh ( m a x ) ma x i m u m g r o u n d w a t e r m o u n d i n g ( b e n e a t h c e n t e r o f b a s i n a t e n d o f i n f i l t r a t i o n p e r i o d ) Gr o u n d - wa t e r Mo u n d i n g , i n fe e t Di s t a n c e f r o m ce n t e r o f b a s i n in x d i r e c t i o n , i n fe e t 0. 3 9 2 0 0. 3 9 0 20 0. 0 1 3 40 0. 0 0 0 50 0. 0 0 0 60 0. 0 0 0 70 0. 0 0 0 80 0. 0 0 0 90 0. 0 0 0 10 0 0. 0 0 0 12 0 Di s c l a i m e r Th i s s p r e a d s h e e t s o l v i n g t h e H a n t u s h ( 1 9 6 7 ) e q u a t i o n f o r g r o u n d - w a t e r m o u n d i n g b e n e a t h a n i n f i l t r a t i o n ba s i n i s m a d e a v a i l a b l e t o t h e g e n e r a l p u b l i c a s a c o n v e n i e n c e f o r t h o s e w i s h i n g t o r e p l i c a t e v a l u e s do c u m e n t e d i n t h e U S G S S c i e n t i f i c I n v e s t i g a t i o n s R e p o r t 2 0 1 0 - 5 1 0 2 " G r o u n d w a t e r m o u n d i n g b e n e a t h hy p o t h e t i c a l s t o r m w a t e r i n f i l t r a t i o n b a s i n s " o r t o c a l c u l a t e v a l u e s b a s e d o n u s e r - s p e c i f i e d s i t e c o n d i t i o n s . A n y ch a n g e s m a d e t o t h e s p r e a d s h e e t ( o t h e r t h a n v a l u e s i d e n t i f i e d a s u s e r - s p e c i f i e d ) a f t e r t r a n s m i s s i o n f r o m t h e US G S c o u l d h a v e u n i n t e n d e d , u n d e s i r a b l e c o n s e q u e n c e s . T h e s e c o n s e q u e n c e s c o u l d i n c l u d e , b u t m a y n o t b e li m i t e d t o : e r r o n e o u s o u t p u t , n u m e r i c a l i n s t a b i l i t i e s , a n d v i o l a t i o n s o f u n d e r l y i n g a s s u m p t i o n s t h a t a r e in h e r e n t i n r e s u l t s p r e s e n t e d i n t h e a c c o m p a n y i n g U S G S p u b l i s h e d r e p o r t . T h e U S G S a s s u m e s n o re s p o n s i b i l i t y f o r t h e c o n s e q u e n c e s o f a n y c h a n g e s m a d e t o t h e s p r e a d s h e e t . I f c h a n g e s a r e m a d e t o t h e sp r e a d s h e e t , t h e u s e r i s r e s p o n s i b l e f o r d o c u m e n t i n g t h e c h a n g e s a n d j u s t i f y i n g t h e r e s u l t s a n d c o n c l u s i o n s . Th i s s p r e a d s h e e t w i l l c a l c u l a t e t h e h e i g h t o f a g r o u n d w a t e r m o u n d b e n e a t h a s t o r m w a t e r i n f i l t r a t i o n b a s i n . M o r e i n f o r m a t i o n c a n b e f o u n d i n t h e U . S . G e o l o g i c a l S u r v e y Sc i e n t i f i c I n v e s t i g a t i o n s R e p o r t 2 0 1 0 - 5 1 0 2 " S i m u l a t i o n o f g r o u n d w a t e r m o u n d i n g b e n e a t h h y p o t h e t i c a l s t o r m w a t e r i n f i l t r a t i o n b a s i n s " . Th e u s e r m u s t s p e c i f y i n f i l t r a t i o n r a t e ( R ) , s p e c i f i c y i e l d ( S y ) , h o r i z o n t a l h y d r a u l i c c o n d u c t i v i t y ( K h ) , b a s i n d i m e n s i o n s ( x , y ) , d u r a t i o n o f i n f i l t r a t i o n p e r i o d ( t ) , a n d t h e i n i t i a l th i c k n e s s o f t h e s a t u r a t e d z o n e ( h i ( 0 ) , h e i g h t o f t h e w a t e r t a b l e i f t h e b o t t o m o f t h e a q u i f e r i s t h e d a t u m ) . F o r a s q u a r e b a s i n t h e h a l f w i d t h e q u a l s t h e h a l f l e n g t h ( x = y ) . Fo r a r e c t a n g u l a r b a s i n , i f t h e u s e r w a n t s t h e w a t e r - t a b l e c h a n g e s p e r p e n d i c u l a r t o t h e l o n g s i d e , s p e c i f y x a s t h e s h o r t d i m e n s i o n a n d y a s t h e l o n g d i m e n s i o n . C o n v e r s e l y , i f th e u s e r w a n t s t h e v a l u e s p e r p e n d i c u l a r t o t h e s h o r t s i d e , s p e c i f y y a s t h e s h o r t d i m e n s i o n , x a s t h e l o n g d i m e n s i o n . A l l d i s t a n c e s a r e f r o m t h e c e n t e r o f t h e b a s i n . U s e r s ca n c h a n g e t h e d i s t a n c e s f r o m t h e c e n t e r o f t h e b a s i n a t w h i c h w a t e r - t a b l e a q u i f e r t h i c k n e s s a r e c a l c u l a t e d . Ce l l s h i g h l i g h t e d i n y e l l o w a r e v a l u e s t h a t c a n b e c h a n g e d b y t h e u s e r . C e l l s h i g h l i g h t e d i n r e d a r e o u t p u t v a l u e s b a s e d o n u s e r - s p e c i f i e d i n p u t s . Th e u s e r M U S T c l i c k t h e blu e " R e - C a l c u l a t e N o w " b u t t o n e a c h t i m e A N Y o f t h e u s e r - s p e c i f i e d i n p u t s a r e c h a n g e d o t h e r w i s e n e c e s s a r y i t e r a t i o n s t o c o n v e r g e o n t h e c o r r e c t s o l u t i o n w i l l n o t b e d o n e an d v a l u e s s h o w n w i l l b e i n c o r r e c t . U s e c o n s i s t e n t u n i t s f o r a l l i n p u t v a l u e s ( f o r e x a m p l e , f e e t a n d d a y s ) In t h e r e p o r t a c c o m p a n y i n g t h i s s p r e a d s h e e t (U S G S S I R 2 0 1 0 - 5 1 0 2 ) , v e r t i c a l s o i l p e r m e a b i l i t y (f t / d ) i s a s s u m e d t o b e o n e - t e n t h h o r i z o n t a l hy d r a u l i c c o n d u c t i v i t y ( f t / d ) . Re - C a l c u l a t e N o w -0 . 0 5 0 0.0 0 0 0.0 5 0 0.1 0 0 0.1 5 0 0.2 0 0 0.2 5 0 0.3 0 0 0.3 5 0 0.4 0 0 0.4 5 0 0 2 0 4 0 6 0 8 0 1 0 0 1 2 0 1 4 0 Gr o u n d w a t e r M o u n d i n g , i n f e e t 34 Dewey Court Northampton, Massachusetts Stormwater Management Report The Berkshire Design Group, Inc. Appendix E – Water Quality Calculations 4 Allen Place, Northampton, MA 01060 (413) 582-7000 bdg@berkshiredesign.com The Berkshire Design Group, Inc. July 8, 2019 Northampton, Dewey Court Stormwater Standard 4 – Water Quality Volume Existing Impervious Area Table 1 shows the proposed impervious surface areas based on major stormwater improvements. The impervious areas include a portion of the roof of 24 Dewey Court, the end of Dewey Court, the entrance drive and driveway, roofs and pathways. Required Water Quality Volume is calculated by applying the following equation: Required Water Quality Volume, = × Where, = Depth Factor, .5” = Impervious Area The volume provided by each practice is also listed. For rain gardens, storage volume was calculated by average end area applied to contours, as shown on the Grading & Drainage Plan. Table 1. Proposed Impervious Areas, Required and Provided WQv Drainage Area ID (See Figure 5) Proposed Impervious Area (sf) Water Quality Volume Required (cf) Water Quality Volume Provided (cf) P1a 3,745 156 Roof to R-Tank #1 P1b 1,898 79 84 P2 1,808 75 75 P3 2,355 98 3,016 P4 3,785 158 Roof to R-Tank #1 P5 721 30 135 P6 6,904 288 Sheet/Pipe flow P7 1,723 72 132 P8 4,111 171 HS-4i provides full treatment - 171 Total 1,127 3,613 July 8, 2019 Northampton – Dewey court Stormwater Standard 4 – Water Quality Volume Page 2 4 Allen Place, Northampton, MA 01060 (413) 582-7000 bdg@berkshiredesign.com Table 2 provides the TSS removal by drainage area. Roofs draining to the infiltration/detention facility are assigned a TSS removal of 80%. Table 2. Proposed Impervious Areas and TSS Removal Drainage Area ID (See Figure 5) Proposed Impervious Area (Ia) (sf) TSS Removal (%) P1a 3,745 80 P1b 1,898 90 P2 1,808 90 P3 2,355 96 P4 3,785 80 P5 721 90 P6 6,904 0 P7 1,723 90 P8 4,111 94 TOTAL 27,050 - The overall TSS removal for this site is 68 percent which falls below the requirement of 80%. However, this site is a re-development project with existing impervious areas of 9,140 square feet which is currently untreated. And the proposed untreated area, P6, is comprised of sheet flow from the existing home roofs and the apartment’s front walkway, and pipe flow from rear roofs. All of this runoff is considered relatively clean. For a redevelopment project, TSS requirement is to be achieved only to the maximum extent practicable. The site design has maximized the use of practices to capture all parking areas and roofs draining to the parking areas at the top of the site. Three rain gardens and stone lined channels convey runoff to a large underground infiltration area in the apartment parking area and a detention facility in the existing driveway. Two hydrodynamic separators provide treatment of parking lot flows. And a fourth rain garden below the apartment building provides treatment and infiltration of patios and one of the apartment roofs. 34 Dewey Court Northampton, Massachusetts Stormwater Management Report The Berkshire Design Group, Inc. Appendix F – Stormwater Management System – Operation & Maintenance Plan 34 Dewey Court July 8, 2019 Northampton, Massachusetts Stormwater Management Report The Berkshire Design Group, Inc. Page 1 Stormwater Management System Operation & Maintenance Plan During Construction The Contractor shall be responsible for inspection and maintenance during construction. At all times, siltation fabric fencing, stakes and straw bales/wattles, sufficient to construct a sedimentation control barrier a minimum of 50 feet long, shall be stockpiled on the site in order to repair established barriers which may be damaged or breached. An inspection of all erosion control and stormwater management systems shall be conducted by the Contractor at least once a week and during all rain storms until the completion of construction. In case of any noted breach or failure, the Contractor shall immediately make appropriate repairs to any erosion control system and notify the engineer of any problems involving stormwater management systems. A rain storm shall be defined as any of the following: • A storm in which rain is predicted to last for twelve consecutive hours or more. • A storm for which a flash flood watch or warning is issued. • A single storm predicted to have a cumulative rainfall of greater than one-half inch. • A storm not meeting the previous three thresholds but which would mark a third consecutive day of measurable rainfall. The Contractor shall also inspect the erosion control and stormwater management systems at times of significant increase in surface water runoff due to rapid thawing when the risk of failure of erosion control measures is elevated. In such instances as remedial action is necessary, the Contractor shall repair any and all significant deficiencies in erosion control systems within two days. The Northampton Department of Public Works shall be notified of any significant failure of stormwater management systems or erosion and sediment control measures, and shall be notified of any release of pollutants to a water body (stream, brook, pond, etc.). The Contractor shall remove the sediment from behind the fence of the sedimentation control barrier when the accumulated sediment has reached one-half of the original installed height of the barrier. This project requires a NPDES General Permit for Stormwater Discharges from Construction Activities. Contractor and Owner are responsible for finalizing a Stormwater Pollution Prevention Plan (SWPPP) and filing for the NDPES permit prior to the start of construction. All clearing, grading, drainage, construction, and development shall be conducted in strict accordance with the SWPPP. 34 Dewey Court July 8, 2019 Northampton, Massachusetts Stormwater Management Report The Berkshire Design Group, Inc. Page 2 Post-Construction Stormwater Management System Owner: Dewey Court Properties LLC 113 Whittier St, Florence, MA 01062 (413) 586-8287 Party Responsible for Operation & Maintenance: Dewey Court Properties LLC 113 Whittier St, Florence, MA 01062 (413) 586-8287 Inspection & Maintenance Schedule: 1) Driveway and Parking Lot Sweeping Driveway and parking area sweeping shall take place annually during the spring cleanup. 2) Stormwater Treatment Chamber The stormwater treatment chambers are Hydrostorm HS 4i units manufactured by Hydroworks, LLC. These units provide water quality for the driveways and The stormwater treatment chamber should be inspected at regular intervals and maintained when necessary to ensure optimum performance. The system shall be inspected at least four times during the first year and at least twice per year thereafter. Sediment shall be removed any time it has built up to more than 6” deep. At a minimum, the unit shall be cleaned once per year. If sediment accumulates fast enough to require removal more than once per year, the inspection frequency shall be increased. The visual inspection should ascertain that the system components are in working order and that there are no blockages or obstructions in the inlet and separation screen. The inspection should also quantify the accumulation of hydrocarbons, trash, and sediment in the system. Measuring pollutant accumulation can be done with a calibrated dipstick, tape measure or other measuring instrument. The CDS system should be cleaned when the level of sediment has reached 12 inches or when an appreciable level of hydrocarbons and trash covers over 50% of the water surface of the separator. The level of sediment is easily determined by measuring from finished grade down to the top of the sediment pile. To avoid underestimating the level of sediment in the chamber, the measuring device must be lowered to the top of the sediment pile carefully. Particles at the top of the pile typically offer less resistance to the end of the rod than consolidated particles toward the bottom of the pile. Sediment shall be removed if it reaches a depth of 12 inches or at a minimum every two years. Sediment shall be removed by a vacuum truck and disposed of in accordance with applicable regulations. 34 Dewey Court July 8, 2019 Northampton, Massachusetts Stormwater Management Report The Berkshire Design Group, Inc. Page 3 3) Subsurface Infiltration Systems Maintenance Requirements A. A routine maintenance effort is required to ensure proper performance of the R-Tank system. The Maintenance program should be focused on pretreatment systems. Ensuring these structures are clean and functioning properly will reduce the risk of contamination of the R-Tank system and stormwater released from the site. Pre-treatment systems shall be inspected yearly, or as directed by the regulatory agency and by the manufacturer (for proprietary systems). Maintain as needed using acceptable practices or following manufacturer’s guidelines (for proprietary systems). B. Inspection and/or Maintenance Ports in the R-Tank system will need to be inspected for accumulation of sediments at least quarterly through the first year of operation and at least yearly thereafter. This is done by removing the cap of the port and using a measuring device long enough to reach the bottom of the R-Tank system and stiff enough to push through the loose sediments, allowing a depth measurement. C. If sediment has accumulated to the level noted in the R-Tank Maintenance Guide or beyond a level acceptable to the Owner’s engineer, the R-Tank system should be flushed. D. A flushing event consists of pumping water into the Maintenance Port and/or adjacent structure, allowing the turbulent flows through the R-Tank system to re-suspend the fine sediments. If multiple Maintenance Ports have been installed, water should be pumped into each port to maximize flushing efficiency. Sediment-laden water can be filtered through a Dirtbag® or approved equivalent if permitted by the locality. 4) Rain Gardens The rain gardens shall be inspected at least four times per year for sediment accumulation and signs of damage or erosion. Sediment shall be removed any time it has accumulated more than ½”. Sediment shall be removed annually, preferably during spring cleanup. At that time, sediment and the previous year’s mulch shall be removed and new mulch installed. Failure of the system to drain (ponding 48 hours after the end of the storm) shall result in inspection and cleaning. Sediments shall be removed and disposed of in accordance with local, state and federal guidelines and regulations. Inspections shall identify any damage or signs of erosion within basins, which shall be repaired immediately. It is recommended that sediment removal be performed after the completion of the spring snow melt. 5) Yard Drains Yard drains should be inspected quarterly and cleaned annually or more often if required. Oil and sediments should be removed and disposed of in accordance with local, state and federal guidelines and regulations. In the case of an oil or bulk pollutant release, the system must be cleaned immediately following the spill and the proper authorities notified. 6) Outlet Control Structures The outlet control structures for the R-Tanks shall be inspected quarterly and after large storms (greater than 2” in 24-hours) to ensure no debris is prohibiting flow through the outlet orifices in the riser pipe. Inspections should confirm that there is no standing water in the structure and that the bottom is visible. All materials removed from the outlet control structure shall be removed and disposed of in accordance with local, state and federal guidelines and regulations. 34 Dewey Court July 8, 2019 Northampton, Massachusetts Stormwater Management Report The Berkshire Design Group, Inc. Page 4 7) Stone Trenches Stone trenches shall be inspected at least four times per year and at least once per year during a rain event. If sediment is found to accumulate on the top of the trench, it shall be removed before any significant accumulation. If observation during a rain event finds the trenches do not convey the runoff as designed, the perforated pipe shall be cleaned and sediment removed as necessary to bring the system back into working order. All materials removed from the trenches or pipes shall be removed and disposed of in accordance with local, state and federal guidelines and regulations. 34 Dewey Court Northampton, Massachusetts Stormwater Management Report The Berkshire Design Group, Inc. Appendix G – Massachusetts DEP Stormwater Checklist