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HomeMy Public PortalAbout4 - Stormwater-Drainage Report STORMWATER/DRAINAGE REPORT Prepared for Proposed Project: 19 Coolidge Hill Road Proponent: 19 Coolidge Hill Owner, LLC Location: 19 Coolidge Hill Road Watertown, Massachusetts .6Of DONALD A. Pf LNENCHER o Civil No. 38M 3T Prepared By: John G. Crowe Associates, Inc. Landscape Architects and Civil Engineers 39 Holton Street Winchester, MA 01890 July 09, 2019 STORMWATER/DRAINAGE REPORT CROWE July 09, 2019 Landscape Architects and Civil Engineers 19 Coolidge Hill Road Winchester, Massachusetts Watertown, Massachusetts Purpose: This purpose of this Stormwater/Drainage Report is to present the stormwater management plan and drainage system design for the Redevelopment of the property at 19 Coolidge Hill Road, Watertown, Massachusetts. Summarv: The Site will include the installation of a stormwater management system that has been designed to meet the MassDEP Stormwater Management Standards and Watertown Stormwater Regulations. As a Redevelopment, the Project is required to provide peak flow mitigation and provide water quality treatment and groundwater recharge to the maximum extent practicable. The proposed design exceeds this requirement by achieving standards set for New Development. The redevelopment objectives of the project's stormwater management design are: 1) to retain drainage on-site to the maximum extent practicable; 2) to detain drainage on-site to reduce peak rates of run-off from the site to the municipal property (Filippello Park) and municipal drainage systems; 3) to reduce peak rates of run-off and run-off volume, thereby reducing the possibility of down-gradient flooding of the municipal drainage systems; and 4) to improve the water quality of the stormwater leaving the site, thereby improving the quality of Watertown's municipal discharge to the Charles River system. The Project has been designed using environmentally-sensitive site design and LID techniques. This design prevents the generation of stormwater and non-point source pollution by reducing impervious surfaces, disconnecting undesirable flow paths, treating stormwater, and recreating the pre-development natural process of infiltration. The site hydrology was analyzed using HydroCAD computer software. The existing conditions drainage areas (EDA's) were delineated based on the ground surface topography and property lines. The total drainage area includes 40,899 square feet (SF) of watershed. Geotechnical subsurface investigations provided evidence that the existing soils are very conducive to subsurface recharge (infiltration). Stormwater run-off from vehicular pavement will be collected and receive treatment (pollutant removal) by integration of proprietary structural BMPs which result in a high rate of Total Suspended Solids (sediment) removal and also trap floatable petroleum products for collection and proper disposal elsewhere. 100 percent of the treated vehicular pavement run-off and run-off from cleaner roof and pedestrian pavement surfaces for all of the 24-hour storms, including the 100-year storm will be infiltrated into the ground. This results in no stormwater run-off contribution to the municipal system, both in terms of peak rates of run-off and volume. STORMWATER/DRAINAGE REPORT CROWE July 09, 2019 Landscape Architects and Civil Engineers 19 Coolidge Hill Road Winchester, Massachusetts Watertown, Massachusetts Existinq Conditions Description and Existinq Hvdroloqv: The existing building and site improvements consist of a decades old industrial commercial use building apparently build in stages its most recent use was apparently warehouse with office, parking and truck docks. The existing hydrologic drainage areas are shown on the following plan, Existinq Hvdroloqv Areas and Drainaqe Desiqn Points. The existing drainage areas are summarized in the Watershed Summary Table and shown on the Existing Hydrology Drainage Areas Plan in this report. The 5 existing drainage areas and 5 drainage design points are shown on the Existing Drainage Areas Plan. The existing and proposed drainage areas are summarized in the Watershed Summary Table included with the drainage area plans in this report. There is a catch basin on the property at a low point near loading docks. It is designated Design Point 1 "(DP-1)", for Existing Drainage Area 1 "(EDA-1)". This catch basin is packed with sediments and debris. The stormwater it receives both from roof and pavement, puddles up and floods this low point during and after storms. The stormwater collected there dissipates slowly into the structure. It is presumed that this catch basin is an infiltration structure because there is no plan record of a connection to the Arlington Street drainage main. For many years the majority of the stormwater from the site, EDA-2 and EDA-3, including landscape, vehicular pavements and roof run-off has discharged directly to the west edge of Filippello Park, DP-2 and DP-3, where it infiltrates into the ground and runs overland to a catch basin near the southwest corner of the park near Arlington Street. The 1937 design plans for the park provided by the Town Engineer show that catch basin is piped to a drainage main in Arlington Street adjacent to the north curb line. A portion of the site drains off site onto Coolidge Hill Road, EDA-4, and is captured in catch basins on the edge of the road, DP-4. The portion of the site adjacent to Arlington Street, EDA-5, drains to the street, DP-5. Soils: Enclosed in this report are copies of the soil borings from geotechnical subsurface investigations. These data demonstrate that the soils are consistently sands, coarse sands, and gravels. The borings also identify rather consistent the groundwater depths. The soil profile provides a very good opportunity for infiltration of stormwater. Three soil borings B-1, B-2, and B-3, provide describe the site soils as consisting of sand, coarse sand, fine to medium sand, and fine gravel throughout the site and STORMWATER/DRAINAGE REPORT CROWE July 09, 2019 Landscape Architects and Civil Engineers 19 Coolidge Hill Road Winchester, Massachusetts Watertown, Massachusetts specifically in the area of the larger infiltration chamber system. These boring locations are shown on the Grading and Utility Site Plan for the project. Subtracting from existing grades at these locations, groundwater is identified at an elevation just below 25 in B-1, at elevation 28 in B-2, and at elevation 26 in B-3. Proposed Conditions: Stormwater Manaqement Improvements and HvdrologY The proposed project will raze the existing building and site improvements and replace them with a new self-storage facility, an interior space for use as a neighborhood or community center, and a neighborhood "pocket" park. The 5 proposed drainage areas and 2 drainage design points are shown on the Proposed Drainage Areas Plan. The existing and proposed drainage areas are summarized in the Watershed Summary Table included with the drainage area plans in this report. The proposed conditions reduce impervious surfaces, both roof and vehicular pavements, resulting in a significant reduction in stormwater peak rates of run-off and run-off volume. The reduction of vehicular pavements results in a significant improvement to stormwater quality. The design of the proposed topography slopes inward at the property line to retain stormwater on the property. The proposed redevelopment layout on this small commercial property is rather limited to a configuration and topographic response similar to the existing building. It is dictated by the property's significant changes in topography sloping from the northwest corner down to the south and east. The design response to these conditions establishes the optimal location for vehicular access from Arlington Street with a parking lot and subsurface infiltration system in the south west portion of the property. The great majority of the stormwater run-off: Proposed Drainage Areas: PDA-1, PDA-2, PDA-3, and PDA-5 are combined at proposed drainage design point 1, DP-1, a subsurface infiltration system described below. Proposed Drainage Area 4, PDA-4, adjacent to Coolidge Hill Road will be contained to the site, captured and directed to a small infiltration structure at DP-4, at the lower end of the drainage area watershed. Infiltration Svstem Desiqn: Two infiltration systems were designed using the Rawl's Table factor for sandy soils, 8.27 inches per hour. The design of the infiltration utilized the very conservative Simple Static Method of infiltration which is integrated into the Hydro-Cad model. The entire STORMWATER/DRAINAGE REPORT CROWE July 09, 2019 Landscape Architects and Civil Engineers 19 Coolidge Hill Road Winchester, Massachusetts Watertown, Massachusetts 100-year volume is storable within the system above the bottom of the infiltration systems. This model is extremely conservative considering the rapid infiltration capability of the soils. Groundwater elevations were established using the soil borings information mentioned above: elevation 25 from B-1 in the area of the chamber infiltration system; and elevation 26 from B-3 closest to the smaller, round infiltration structure. The design of the large chamber system is based on the "sub-routine" for the Lane StormKeeper SK75 system within a 6-inch, 3-dimensional containment of washed, processed stone and filter fabric. The bottom of the system (stone apron) was set at elevation 29.50, more than 4 feet above the groundwater elevation of 25. The small infiltration structure is a typical 6-foot diameter precast leaching (aka cesspool) structure, also surrounded by 6-inches of stone and geo-textile filter fabric. The bottom of the gravel apron is set at elevation 34.50, more than 4 feet above the groundwater elevation of 26. Hvdroloqic Analvsis Results: Four storm events were modeled including the 2, 10, 25, and 100-year, 24-hour storms. Please refer to the Existing and Proposed Conditions HydroCAD Reports included in the Appendix. Peak flows and total runoff volumes are provided for each design point, in Tables 1 a, 2a, 3a, & 4a; and Tables 1 b, 2b, 3b, & 4b below respectively. The results indicate that peak rates of runoff and runoff volumes are zero-ed out. Stormwater discharges from the site are eliminated for all modelled storm events due to the retention and infiltration of the stormwater. Peak Rates of Run-off Table— 1a: Peak Flow (CFS) to Desiqn Point DP-1 Exist. Leaching Catch Basin Prop. Retention/Infiltration Chambers Storm: 2-Year 10-Year 25-Year 100-Year Rainfall (In): 3.2 4.9 6.2 8.9 Existing 0.76 1.17 1.48 2.14 Proposed 1.98 3.38 4.49 6.85 Discharge 0.00 0.00 0.00 0.00 Table—2a: Peak Flow (CFS)to Desiqn Points DP-2 and DP-3 Exist. Filippello Park Prop. Added to DP-1 Storm: 2-Year 10-Year 25-Year 100-Year Rainfall (In): 3.2 4.9 6.2 8.9 Existing 1.58 2.57 3.32 4.86 Discharge Added to DP-1 Added to DP-1 Added to DP-1 Added to DP-1 STORMWATER/DRAINAGE REPORT CROWE July 09, 2019 Landscape Architects and Civil Engineers 19 Coolidge Hill Road Winchester, Massachusetts Watertown, Massachusetts Table-3a: Peak Flow (CFS) to Desiqn Point DP-4 Exist. Coolidqe Hill Road Drainaqe Svstem Prop. Infiltration Area Drain Storm: 2-Year 10-Year 25-Year 100-Year Rainfall (In): 3.2 4.9 6.2 8.9 Existing 0.01 0.22 0.31 0.51 Proposed 0.00 0.00 0.00 0.41 Discharge 0.00 0.00 0.00 0.00 Table-4a: Peak Flow (CFS)to Design Point DP-5 Exist. Arlington Street Drainaqe Svstem Prop. Added to DP-1 Storm: 2-Year 10-Year 25-Year 100-Year Rainfall (In): 3.2 4.9 6.2 8.9 Existing 0.27 0.41 0.52 0.75 Discharge Added to DP-1 Added to DP-1 Added to DP-1 Added to DP-1 Volumes Table- 1 b: Runoff Volume (Ac-Ft)to Desiqn Point DP-1 Exist. Leachinq Catch Basin Prop. Retention/Infiltration Chambers Storm: 2-Year 10-Year 25-Year 100-Year Rainfall (In): 3.2 4.9 6.2 8.9 Existing 0.059 0.092 0.118 0.171 Proposed 0.680 0.254 0.339 0.521 Discharge 0.000 0.000 0.000 0.000 Table-2b: Runoff Volume (Ac-Ft)to Design Points DP-2 and DP-3 Exist. FilivDello Park Prop. Added to DP-1 Storm: 2-Year 10-Year 25-Year 100-Year Rainfall (In): 3.2 4.9 6.2 8.9 Existing 0.115 0.191 0.250 0.372 Discharge Added to DP-1 Added to DP-1 Added to DP-1 Added to DP-1 Table-3b: Runoff Volume (Ac-Ft)to Desiqn Point DP-4 Exist. Coolidge Hill Road Drainage Svstem Prop. Infiltration Area Drain Storm: 2-Year 10-Year 25-Year 100-Year Rainfall (In): 3.2 4.9 6.2 8.9 Existing 0.007 0.015 0.022 0.036 Proposed 0.000 0.000 0.010 0.036 Discharge 0.000 0.000 0.000 0.000 Table-4b: Runoff Volume (Ac-Ft)to Design Point DP-5 Exist. Arlington Street Drainage Svstem Prop. Added to DP-1 Storm: 2-Year 10-Year 25-Year 100-Year Rainfall (In): 3.2 4.9 6.2 8.9 Existing 0.021 0.032 0.041 0.060 Discharge Added to DP-1 Added to DP-1 Added to DP-1 Added to DP-1 STORMWATER/DRAINAGE REPORT CROWE July 09, 2019 Landscape Architects and Civil Engineers 19 Coolidge Hill Road Winchester, Massachusetts Watertown, Massachusetts Water Qualitv Treatment: Three (3) Contech Vort-Sentry catch-basin/treatment structures unit have been incorporated at the design of the vehicular pavement area. These structures separate and collect of petroleum-based pollutants normally associated with run-off from vehicular pavements. These structures will achieve 91.5% of TSS removal which exceeds the target removal of 44% of total suspended solids prior to discharge to infiltration systems. Required Water Qualitv Volume and Required Recharqe Volume The need for Calculations of Required Water Quality Volume and Required Recharge Volume which quantify less than 100 percent of the project run-off is eliminated by the attainment of Watertown Stormwater Regulations to retain and infiltrate all of the property stormwater from all 24-hour design storms. Attainment of fractional volumes is inherent in 100 percent retention. Phosphorus Load Reduction Complete stormwater treatment for phosphorus pollution is inherent in the containment, sediment removal attained by the proprietary BMP structures, and the retention/infiltration of 100 percent of the proposed stormwater run-off. The need for Phosphorus Load Reduction Calculations is eliminated by the TSS removal and 100 percent retention and infiltration of the property stormwater from all design storms. Proof of reduction of these loads contributed to down gradient resources is inherent in 100 percent retention. STORMWATER/DRAINAGE REPORT CROWE July 09, 2019 Landscape Architects and Civil Engineers 19 Coolidge Hill Road Winchester, Massachusetts Watertown, Massachusetts MA DEP Stormwater Handbook Performance Standards GENERAL: The project is a Redevelopment Project. STANDARD 1: NO NEW UNTREATED DISCHARGES There are no new untreated discharges from the property. STANDARD 2: PEAK RATE ATTENUATION The drainage calculations demonstrate that there will be no discharges from the proposed project from storms up to and beyond the 100 year 24-hour storm. Inherent in this stormwater management design is post-development discharge volumes and peak discharge rates of zero for the 2, 10, 25, and 100 year 24-hour storm events. STANDARD 3: RECHARGE All run-off from the proposed project up to and beyond the 100 year 24-hour storm will be infiltrated in either an open-to-surface infiltration retention basin or underground infiltration structures in accordance with Massachusetts Stormwater Guidelines. The soils are excellent for stormwater recharge into the ground. • The bottoms of infiltration structures are more than four feet above groundwater. • The Simple Dynamic method for determination of the adequacy of storage volume was utilized. • The Rawls Table infiltration rate for the soils was established from soil data reported in geotechnical studies of the property. • Inherent in this stormwater management design with zero volume of discharge and 100 percent recharge is achievement of the Required Recharge Volume. STANDARD 4: WATER QUALITY The existing conditions include higher potential pollutant loads associated with vehicular trips and vehicular residence (trucks and cars) inherent to a warehouse use. The proposed use greatly lowers that potential. In addition, the proposed stormwater management design incorporates the capture of pollutants from vehicular pavement run-off including the removal of floatable petroleum-based pollutants and Total Suspended Solids in excess of 80%. Inherent in the TSS removal and infiltration/recharge of all modelled 24-hour storm events is the highest possible reduction of, if not the elimination of, the potential for phosphorus discharge from the property to down-gradient water resources. Run-off from vehicular pavements will be captured in Water Quality Treatment Catch Basins ("WQCB's") (Vort-Sentry proprietary BMP structures constructed by Contech) which trap the petroleum products and spin-out sediments which will be periodically removed from the structures and property. After treatment by the WQCB's, the stormwater is piped with some of the higher quality, "clean" stormwater from the STORMWATER/DRAINAGE REPORT CROWE July 09, 2019 Landscape Architects and Civil Engineers 19 Coolidge Hill Road Winchester, Massachusetts Watertown, Massachusetts proposed building roof, pedestrian areas, and landscape areas to an under-pavement system of infiltration chambers, Most of the run-off from the roof, landscape, and pedestrian areas is directed to a dry, 100 year storm sized infiltration retention basin. The project is within the Charles River watershed. This watershed has a TMDL for phosphorous which requires reduction of phosphorus from stormwater. Sediment removal, stormwater retention, and recharge of all modelled stormwater to the ground maximizes the opportunity for phosphorus removal from vehicular pavement stormwater. STANDARD 5: LAND USES WITH HIGHER POTENTIAL POLLUTANT LOADS The most recent pre-redevelopment use of the property could be considered a Land Use with Higher Potential Pollutant Loads. The proposed use is not a Land Use with Higher Potential Pollutant loads. STANDARD 6: CRITICAL AREAS The project is not in the watershed of a critical area. STANDARD 7: REDEVELOPMENTS This project meets and exceeds the stormwater standards for a Redevelopment project. STANDARD 8: CONSTRUCTION PHASE POLLUTION PREVENTION AND EROSION AND SEDIMENTATION CONTROL Construction phase pollution prevention and erosion and sedimentation control measures are incorporated into the plans. STANDARD 9: OPERATION AND MAINTENANCE PLAN A Post-Construction Operation and Maintenance Plan is included. STANDARD 10: PROHIBITION OF ILLICIT DISCHARGES The project as designed will contain no illicit discharges. STORMWATER/DRAINAGE REPORT CROWE July 09, 2019 Landscape Architects and Civil Engineers 19 Coolidge Hill Road Winchester, Massachusetts Watertown, Massachusetts SOIL BORING LOGS PES ASSOCIATES Boring Log No. B-1 (OW) Proposed Self Storage Building Location:19 Coolidge Hill Rd. Watertown Client:Black Hawk Investments Method:Hollow Stem Augers Ground EL: Hammer:Safety Hammer weight(lb):140 Hole depth(ft):26 Sampler:2"OD Split-spoon Drop(in):30 G.W.T.@ Drilling(ft): 17 Drilled by:NE Boring Driller: Drill Date:8/20/2107 Logged by:S.Reynolds ■ SPT.blow/ft W= Q (V m co oPiezoeter Moisture% ma o z =m Soil Description o 20 40 6a 0 �Foncrete SM Asphalt ' P —Slough S Sand,poorly graded,coarse to fine sand,mostly fine to medium sand, ou h '•'' 9 14-14-14-16 0.2 S1 <;r 5-10%fine gravel,5-10%non-plastic fines,light brown,dry ■y 5 tier 22-16-10-15 0.2 S2 v 1■1 /'•' Bentonite f Sp Sand,poorly graded,coarse to fine sand,mostly fine t medium,8-12 — Silica Sand %fine gravel,3-5%non-plastic fines,light brown,dry 10 :':i'1.::: 7-11-9-9 0.3 S3 jaLLSM GLACAL TILL:Silty Sand,widely graded,coarse to fine sand,20-30% 1=r.: -,...: gravel,10-15%non-plastic fines,moist to wet,gray-brown,strong a , Ad A 15 46-44-50-45 0.3 S4 gasoline d d 19 n Y=L J '■—Y' � L�5 �n4j 20 -' .`,�-;.`,' 34-36-34-24 600 S5 �A�' U — -' iz -� Silica Sand A A AAA' ❑ G 25 A a — Boring completed at depth of 26 feet 0 w — 30 J C.— (n 35 Remarks: Sample from 19-21 feet sent to Contest for VPH/EPH analysis PLATE 1 PES ASSOCIATES Boring Log No. B-2 Proposed Self Storage Building Location: 19 Coolidge Hill Road Watertown, MA Client: Black Hawk Investments Method:HSA Ground EL: Hammer:Safety Hammer weight(lb): 140 Hole depth(ft):32 Sampler:2"OD Split-spoon Drop(in):30 G.W.T.@ Drilling(ft): none Driller:New England Boring Equi)ment:Truck Rig Drill Date:8/20/17 Logged by:S.Reynolds S M a, u, - U) 0 SPT.blow/ft o z Co0 j Soil Description O PID(ppm) Notes 0 20 40 60 0 0 SP Gravelly Sand,poorly graded,coarse to fine sand, mostly medium, 15-25%gravel,5-8%non-plastic — fines,dry,gray-brown — N 5 5 M W y - - W CI O v a 10 O M 10 o = S1 5-8-8-3 = t I LU v .o F U 0 15 15 'v s 0 a U ai LL 20 ML Sandy Silt, non-plastic,20-30%fine sand light brown O 20 E _ S2 8-19-12-1z with lense of silty gravel and silty sand — 5 — — v 25 25 SP Gravelly Sand,poorly graded,coarse to fine sand, 3 — mostly medium, 15-20%gravel,5-8%non-plastic — N — fines,dry,gray-brown — t d Z — — U 0 30 O 30 N— S3 N 17-23-23-3 J = Boring completed at depth of 32 feet 35 35 Remarks: Plate 1 PES ASSOCIATES Boring Log No. B-3 Proposed Self Storage Building Location: 19 Coolidge Hill Road Watertown, MA Client: Black Hawk Investments Method:HSA Ground EL: Hammer:Safety Hammer weight(lb): 140 Hole depth(ft): 12 Sampler:2"OD Split-spoon Drop(in):30 G.W.T.@ Drilling(ft): none Driller:New England Boring Equi)ment:Truck Rig Drill Date:8/20/17 Logged by:S.Reynolds t co U) 0 SPT.blow/ft o � z m a j Soil Description O PID(ppm) Notes 0 20 40 60 0 Asphalt 0 SP Sand,poorly graded,coarse to fine sand,mostly U 'g medium to fine,5-10%gravel,5-10%non-plastic fines,dry,light brown S1 5-8-8-3 N 2 :..:C7 2 M W N W 0 o SP Sand,poorly graded,coarse to fine sand,mostly a medium to fine,8-12%gravel,3-5%non-plastic a 4 fines,dry,light gray brown 4 0 t — — w O F U o 6 S2 8-9-8-8 6 a — — v o 0 n U y — — LL 8 O 8 8 E V - - L V - - W 3 - - 10 O ■ 10 d _ R 3 O t S3 5-10-12-K. d U 12 12 Boring completed at depth of 12 feet o. 14 14 Remarks: Plate 2 STORMWATER/DRAINAGE REPORT CROWE July 09, 2019 Landscape Architects and Civil Engineers 19 Coolidge Hill Road Winchester, Massachusetts Watertown, Massachusetts TSS REMOVAL CALCS Project: 19 Coolidge Hill Road Location: Watertown, MA ii►-NTE Prepared For: Crowe ENGINEERED SOLUTIONS Purpose: To calculate the water quality flow rate (WQF) over a given site area. In this situation the WQF is derived from the first 1"of runoff from the contributing impervious surface. Reference: Massachusetts Dept. of Environmental Protection Wetlands Program / United States Department of Agriculture Natural Resources Conservation Service TR-55 Manual Procedure: Determine unit peak discharge using Figure 1 or 2. Figure 2 is in tabular form so is preferred. Using the tc, read the unit peak discharge (qu)from Figure 1 or Table in Figure 2. qu is expressed in the following units: cfs/mil/watershed inches (csm/in). Compute Q Rate using the following equation: Q= (qu) (A) (WQV) where: Q =flow rate associated with first 1" of runoff qu =the unit peak discharge, in csm/in. A= impervious surface drainage area (in square miles) WQV=water quality volume in watershed inches (1" in this case) Structure ImpV. A tc t' WQV Name acres (miles2 min) (hr) in qu (csm/in.) Q (cfs) WQCB 01 0.03 0.0000438 5.0 0.083 1.00 795.00 0.03 WQCB 02 0.08 0.0001203 5.0 0.083 1.00 795.00 0.10 WQCB 03 0.09 0.0001344 5.0 0.083 1.00 795.00 0.11 a0 E e m w 2 T. w y E E N o - _ H a m 10 ? N M m e Z 'm 0 W 2 z O E LL W LL Y W . . 3 Ei i m E o W eE (L W z N a� o LL co CYy N w O o O z J_ a Q ❑y m e a �n �n W W 3 LL w . . 5 w < 3 Q o w s -.o w W o � x c7 o E o Z tC E Q ~ O z o a w o 1w z w �z0 p z �_ ani E m m N m Q m w o F U W U p y0 O N �O~ w n 3 w w a < a w z z ¢ NU U O mew H D �U Q a o a F a a > o w z z a ¢m ¢ wN� Z m LL w ¢ n w o c7w O LL Jza W W y p w w m U a zo w _ 03 U) Q F z > Fm �n m rn I ¢ w w a z o a �� z ~w p J 2 z H D O ¢ O n N 3 a m a ? O m ¢ z j w c7 w w y j p 0 d' a Z 50 x LL Ya w Q0 U. � Q�pr Z O¢ N Z E NF �z w U pWxp W� o cRi d w w W z0 ¢ cz w ¢ a~=� > (n m0 F J a�cm Ow E2 20 F U zN�W W �z Fy o LL o 0 0 0 wo g3 °¢ w 0 o¢wa Q �¢ W or a �o m �o i. W 2a ww xw a w u>Q� mz o0o c9m oN o NW N w OW>< u.F O O W Qatn ao=o �z 0 zEza°'z 0¢ w F m E 0 O 0 Z D . twilr ZU mO ww w (a7»d~W } m F a oX.E m e �n �n �Z 3aw U mz 0> zxU2ja d' 30 z 0' U� ~ m t3 o 0 0 o a_ m � U m p--,'w �w w V = �O oa W 2zwui? is a 7w�¢m3 Z m> J U) 'a9 om LL 0 0 0 r2" Oom>w NF o zcoi 0.iw W wF a WQ Fo.. o 0 0 wwc~.i tim z� - w�Zaow ~ ~N O O Z m m LL zowww Wo �01,w�wo FW x F wa J NWNwW c¢.\i �UNz pm 0 zw y a a a d m F, m g � wzwnP p-o zwr=mzy� m O '. - w�wF z F ¢w_ ! Oaa zm z FJ H p.. Zm4mU o3a mo3-zp W, m 3V o Z w z ~ d o J'-w �w �mFzz z 2i aiz g 0 0 �M o m N a_wzrnm i-w azwuw¢aw =� m 0 p ?3 W w z 0 o w i 0 a O r r m r lw L: v >U a -o- x dmlwzp m�W-d omyW- NZ 0W z 0=o Z a�j0z Jz z 2, J z o E bc w w z>ZFO>wy Cua eVeoQ>u wp Wf� ap �LLO a > O pwpmatdwm 6omazma;- n8 Z 2 zzO U m >y W3NJOZN�aWw p NaWdg00ti w K ¢ ON0 W xr rr avN Q FONU_W KD W QU ZQm OK000M 7w,-M n �� p v �aa O ox Omxzzwo� om¢QGQ z0Q0Qc0Q Z 333a ry ❑¢ Q O Z W Nw W tW/la UZm FJxmNmKK� W 'c ~� a 0 0 � 0 m m . LL woIz �oo00�00 azzz00000> o �u N x x x x x x wUpLLU>UNNU yaaU>OOU? iM me N¢ S in >U F W O> N m U mm w aw a w Irc r� ( Q LL o N(D \ m � �- O d U� pe I w qaW p zi z w O'S Y a w U) Q Z U O las IL Via€ OW �o mz W- LL o� &c 0= W— w N O w a r � wx m J z �► z_ 0 U Nd 99:E UOZ/£IS 0M0'110-SHSA\0M0\SONIMVllO @1VONVIS 00\SH AiUNBS1210A 9ZUN9VUV9NI\OV3MVfiN00VI 0141110TECHR ENGINEERED SOLUTIONS VORTSENTRr HS ESTIMATED NET ANNUAL TSS REDUCTION BASED ON THE RATIONAL RAINFALL METHOD 19 COOLIDGE HILL ROAD WATERTOWN, MA Area 0.03 ac Unit Site Deignation WQCB 01 Weighted C 0.9 Rainfall Station # 69 t, 5 min Design Ratio' 0.0010 VSHS Model HS36 VSHS Treatment Capacity 0.55 cfs Rainfall Intensity' Flow Rate (cfs) Operating Rate cfs/ft3 %Total Rainfall Rel. Effcv M in/hr 0.02 0.00 0.00002 10.2% 10.0% 0.04 0.00 0.00004 9.6% 9.5% 0.06 0.00 0.00006 9.4% 9.3% 0.08 0.00 0.00008 7.7% 7.6% 0.10 0.00 0.00010 8.6% 8.4% 0.12 0.00 0.00011 6.3% 6.2% 0.14 0.00 0.00013 4.7% 4.6% 0.16 0.00 0.00015 4.6% 4.5% 0.18 0.00 0.00017 3.5% 3.5% 0.20 0.01 0.00019 4.3% 4.3% 0.25 0.01 0.00024 8.0% 7.8% 0.30 0.01 0.00029 5.6% 5.5% 0.35 0.01 0.00033 4.4% 4.3% 0.40 0.01 0.00038 2.5% 2.5% 0.45 0.01 0.00043 2.5% 2.5% 0.50 0.01 0.00048 1.4% 1.4% 0.75 0.02 0.00071 5.0% 4.9% 1.00 0.03 0.00095 1.0% 1.0% 1.50 0.04 0.00143 0.0% 0.0% 2.00 0.05 0.00190 0.0% 0.0% 3.00 0.08 0.00285 0.5% 0.5% 98.0% % rain falling at>3"/hr= 0.0% Removal Efficiency Adjustment4= 6.5% Predicted Net Annual Load Removal Efficiency= 91.5% 1 - Design Ratio= (Total Drainage Area x Runoff Coefficient) /VortSentry HS Treatment Volume =The Total Drainage Area and Runoff Coefficient are specified by the site engineer. 2-Operating Rate (cfs/ft)= Rainfall Intensity("/hr)x Design Ratio 3- Based on 10 years of hourly precipitation data from NCDC Station 770, Boston WSFO AP, Suffolk County, MA 4- Reduction due to use of 60-minute data for a site that has a time of concentration less than 30-minutes. 0141110TECHR ENGINEERED SOLUTIONS VORTSENTRr HS ESTIMATED NET ANNUAL TSS REDUCTION BASED ON THE RATIONAL RAINFALL METHOD 19 COOLIDGE HILL ROAD WATERTOWN, MA Area 0.08 ac Unit Site Deignation WQCB 02 Weighted C 0.9 Rainfall Station # 69 t, 5 min Design Ratio' 0.0030 VSHS Model HS36 VSHS Treatment Capacity 0.55 cfs Rainfall Intensity' Flow Rate (cfs) Operating Rate cfs/ft3 %Total Rainfall Rel. Effcv(%) in/hr 0.02 0.00 0.00005 10.2% 10.0% 0.04 0.00 0.00010 9.6% 9.5% 0.06 0.00 0.00016 9.4% 9.3% 0.08 0.01 0.00021 7.7% 7.6% 0.10 0.01 0.00026 8.6% 8.4% 0.12 0.01 0.00031 6.3% 6.2% 0.14 0.01 0.00037 4.7% 4.6% 0.16 0.01 0.00042 4.6% 4.5% 0.18 0.01 0.00047 3.5% 3.5% 0.20 0.01 0.00052 4.3% 4.3% 0.25 0.02 0.00065 8.0% 7.8% 0.30 0.02 0.00078 5.6% 5.5% 0.35 0.02 0.00092 4.4% 4.3% 0.40 0.03 0.00105 2.5% 2.5% 0.45 0.03 0.00118 2.5% 2.5% 0.50 0.03 0.00131 1.4% 1.4% 0.75 0.05 0.00196 5.0% 4.9% 1.00 0.07 0.00261 1.0% 1.0% 1.50 0.10 0.00392 0.0% 0.0% 2.00 0.14 0.00523 0.0% 0.0% 3.00 0.21 0.00784 0.5% 0.5% 98.0% % rain falling at>3"/hr= 0.0% Removal Efficiency Adjustment4= 6.5% Predicted Net Annual Load Removal Efficiency= 91.5% 1 - Design Ratio= (Total Drainage Area x Runoff Coefficient) /VortSentry HS Treatment Volume =The Total Drainage Area and Runoff Coefficient are specified by the site engineer. 2-Operating Rate (cfs/ft)= Rainfall Intensity("/hr)x Design Ratio 3- Based on 10 years of hourly precipitation data from NCDC Station 770, Boston WSFO AP, Suffolk County, MA 4- Reduction due to use of 60-minute data for a site that has a time of concentration less than 30-minutes. 0141110TECHR ENGINEERED SOLUTIONS VORTSENTRr HS ESTIMATED NET ANNUAL TSS REDUCTION BASED ON THE RATIONAL RAINFALL METHOD 19 COOLIDGE HILL ROAD WATERTOWN, MA Area 0.09 ac Unit Site Deignation WQCB 03 Weighted C 0.9 Rainfall Station # 69 t, 5 min Design Ratio' 0.0030 VSHS Model HS36 VSHS Treatment Capacity 0.55 cfs Rainfall Intensity' Flow Rate (cfs) Operating Rate cfs/ft3 %Total Rainfall Rel. Effcv(%) in/hr 0.02 0.00 0.00006 10.2% 10.0% 0.04 0.00 0.00012 9.6% 9.5% 0.06 0.00 0.00018 9.4% 9.3% 0.08 0.01 0.00023 7.7% 7.6% 0.10 0.01 0.00029 8.6% 8.4% 0.12 0.01 0.00035 6.3% 6.2% 0.14 0.01 0.00041 4.7% 4.6% 0.16 0.01 0.00047 4.6% 4.5% 0.18 0.01 0.00053 3.5% 3.5% 0.20 0.02 0.00058 4.3% 4.3% 0.25 0.02 0.00073 8.0% 7.8% 0.30 0.02 0.00088 5.6% 5.5% 0.35 0.03 0.00102 4.4% 4.3% 0.40 0.03 0.00117 2.5% 2.5% 0.45 0.03 0.00131 2.5% 2.5% 0.50 0.04 0.00146 1.4% 1.4% 0.75 0.06 0.00219 5.0% 4.9% 1.00 0.08 0.00292 1.0% 1.0% 1.50 0.12 0.00438 0.0% 0.0% 2.00 0.15 0.00584 0.0% 0.0% 3.00 0.23 0.00876 0.5% 0.5% 98.0% % rain falling at>3"/hr= 0.0% Removal Efficiency Adjustment4= 6.5% Predicted Net Annual Load Removal Efficiency= 91.5% 1 - Design Ratio= (Total Drainage Area x Runoff Coefficient) /VortSentry HS Treatment Volume =The Total Drainage Area and Runoff Coefficient are specified by the site engineer. 2-Operating Rate (cfs/ft)= Rainfall Intensity("/hr)x Design Ratio 3- Based on 10 years of hourly precipitation data from NCDC Station 770, Boston WSFO AP, Suffolk County, MA 4- Reduction due to use of 60-minute data for a site that has a time of concentration less than 30-minutes. STORMWATER/DRAINAGE REPORT CROWE July 09, 2019 Landscape Architects and Civil Engineers 19 Coolidge Hill Road Winchester, Massachusetts Watertown, Massachusetts DRAINAGE AREA MAPS AND SUMMARY O a m O m 00 � d O J � Q Q m V m oo W � o. "I m s o o o 0 o V N d c-1 N Ln a a 0 Y Ln m x M 0 0 0 0 w W M N M Q ^ N m O N O O O 1* M d Ln N N a a 0 w � o 0 0 o o Q N V M m pi o •--� M o o m O d c-I c-I Ln oo ro a a 0 a Lf Ln 00 V N 'X ^ u1 n O Ln O U W N `"� ^ � fl O O 2 o 0 o 0 0 0 o a_ O O c-1 c-I N a a 0 Lo � w o oLn � o 0 0Ln E 7 O m a 0 ON o N 0 vn o m m o ti o d oo —1 N -1 oo m aJ a) o 1O 0 C •x m o ^ o 0 o m r1 oo 0 0 � Y N 0 O O a) aj Q1 Q v a U a) � CL c 0 O J N _ Q C O al � J O u a1 (J j -o N m ai rl d � o N^ k 3 Q II a O Door LLJ 60 : _ 13NbZ I/y,/�/� /l/i/lei Mi / I I/ IIIIIIN / / _ _ ,Illl/lllllllllj '�IIII/lll�W �r o° £-da Lo z M N — W o N N �i IC \4 w 3 c �� k -iW ~I � W- �' o —o _r_ W x i & Q M T$ , $w I W , d o CO w - „,a ow �� � r L? 12 14 Ro, e ' A�.;° os 0 zo o- ?g$N�B�p -�sss, IM � g _ a s o- ai« / Qo p a' � �: _ su m 3� o los�se � = .,_W �� _� U�sNU�o�a rc gRL,NGTON STREET \ ,ezo RELocnnau ar � W pgs �ie8 >�g� o n � �M Q � —e g :lam oQ O S w x ry 4 e 20 Q zoo >w�' E', a 3 e e x I Q °z•-®� _ z „\ ¢� _2 1 3NKJZ „� k lllll���,/Iljll/i/lei l j m c „ llrrlll llrllrlll l/ s� Q w �rr;,r,rl llrlllll rrlrl � � N .IGldr�lsr4r°Irl/l saw. mi NIXIE cg rcE mE zi T I \ti I i o N Q O raj oN E l D o0 w l/ ant _�� 16 ® 4 a� ux"T o�HINT 4wa c I oO H!P' o� s o� x c MINOR i limpsH"W NAM ARLN-Si T8€>�g� o STORMWATER/DRAINAGE REPORT CROWE July 09, 2019 Landscape Architects and Civil Engineers 19 Coolidge Hill Road Winchester, Massachusetts Watertown, Massachusetts EXISTING CONDITIONS HYDROCAD CALCS 7L DP-4 Coolidge Hill d EDA-4 9L C 1S 2S 3S 4S DP-1 Exist Leach Basin EDA-1 EDA-1 EDA-2 EDA-3 EDA-4 6L C 5S ( / v DP-5 Arlington Street EDA-5 EDA-5 $L DP-2 + DP-3 Filippello Park EDA-2 and EDA-3 Subcat Reach on Link Routing Diagram for 19 Coolidge Hill Rd-Watertown Existing 2019 07 0: Prepared by{enter your company name here}, Printed 7/2/2019 HydroCAD®10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC 19 Coolidge Hill Rd - Watertown Existing 2019 07 02 Prepared by {enter your company name here) Printed 7/2/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Page 2 Area Listing (all nodes) Area CN Description (acres) (subcatchment-numbers) 0.020 32 Landscape, HSG A (4S) 0.023 98 Pedestrian Pavement, HSG A (3S, 4S, 5S) 0.570 98 Roof, HSG A (1 S, 2S, 3S) 0.105 76 Steep Slope Landscape, HSG A (3S) 0.221 98 Vehicular Pavement, HSG A (1 S, 2S, 3S, 4S, 5S) 0.939 94 TOTAL AREA 19 Coolidge Hill Rd - Watertown Existing 2019 07 02 Prepared by {enter your company name here) Printed 7/2/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Page 3 Soil Listing (all nodes) Area Soil Subcatchment (acres) Group Numbers 0.939 HSG A 1 S, 2S, 3S, 4S, 5S 0.000 HSG B 0.000 HSG C 0.000 HSG D 0.000 Other 0.939 TOTAL AREA 19 Coolidge Hill Rd - Watertown Existing 2019 07 02 Prepared by {enter your company name here) Printed 7/2/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Page 4 Ground Covers (all nodes) HSG-A HSG-B HSG-C HSG-D Other Total Ground Subcatchment (acres) (acres) (acres) (acres) (acres) (acres) Cover Numbers 0.020 0.000 0.000 0.000 0.000 0.020 Landscape 4S 0.023 0.000 0.000 0.000 0.000 0.023 Pedestrian Pavement 3S, 4S, 5S 0.570 0.000 0.000 0.000 0.000 0.570 Roof 1 S, 2S, 3S 0.105 0.000 0.000 0.000 0.000 0.105 Steep Slope Landscape 3S 0.221 0.000 0.000 0.000 0.000 0.221 Vehicular Pavement 1 S, 2S, 3S, 4S, 5S 0.939 0.000 0.000 0.000 0.000 0.939 TOTAL AREA 19 Coolidge Hill Rd - Watertown Existing 2019 07 02 Type /// 24-hr 2 Year Rainfall=3.20" Prepared by {enter your company name here) Printed 7/2/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Page 5 Time span=0.00-30.00 hrs, dt=0.02 hrs, 1501 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment 1 S: EDA-1 Runoff Area=10,306 sf 100.00% Impervious Runoff Depth=2.97" Tc=5.0 min CN=98 Runoff=0.76 cfs 0.059 of Subcatchment2S: EDA-2 Runoff Area=8,757 sf 100.00% Impervious Runoff Depth=2.97" Tc=5.0 min CN=98 Runoff=0.64 cfs 0.050 of Subcatchment3S: EDA-3 Runoff Area=15,212 sf 70.00% Impervious Runoff Depth=2.26" Flow Length=307' Tc=5.0 min CN=91 Runoff=0.94 cfs 0.066 of Subcatchment4S: EDA-4 Runoff Area=3,005 sf 70.35% Impervious Runoff Depth=1.27" Tc=5.0 min CN=78 Runoff=0.10 cfs 0.007 of Subcatchment5S: EDA-5 Runoff Area=3,619 sf 100.00% Impervious Runoff Depth=2.97" Tc=5.0 min CN=98 Runoff=0.27 cfs 0.021 of Link 6L: DP-5 Arlington Street EDA-5 Inflow=0.27 cfs 0.021 of Primary=0.27 cfs 0.021 of Link 7L: DP-4 Coolidge Hill Rd EDA-4 Inflow=0.10 cfs 0.007 of Primary=0.10 cfs 0.007 of Link 8L: DP-2+ DP-3 Filippello Park EDA-2 and EDA-3 Inflow=1.58 cfs 0.115 of Primary=1.58 cfs 0.115 of Link 9L: DP-1 Exist Leach Basin EDA-1 Inflow=0.76 cfs 0.059 of Primary=0.76 cfs 0.059 of Total Runoff Area = 0.939 ac Runoff Volume = 0.202 of Average Runoff Depth = 2.58" 13.34% Pervious = 0.125 ac 86.66% Impervious = 0.814 ac 19 Coolidge Hill Rd - Watertown Existing 2019 07 02 Type /// 24-hr 2 Year Rainfall=3.20" Prepared by {enter your company name here) Printed 7/2/2019 HydroCADO 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 6 Summary for Subcatchment 1S: EDA-1 Runoff = 0.76 cfs @ 12.07 hrs, Volume= 0.059 af, Depth= 2.97" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Type III 24-hr 2 Year Rainfall=3.20" Area (sf) CN Description 1,530 98 Vehicular Pavement, HSG A 8,776 98 Roof, HSG A 10,306 98 Weighted Average 10,306 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, ROOFTOP (assume minimum Tc) Subcatchment 1 S: EDA-1 Hydrograph 0.8=�_ + 0.76 cfs Te ■Runoff 0.75� fi I fi �I 0-7--�/-I 14 0.65� - - -- -tea-f t1�3�2�0�' 0.6�-/_ A R t Koff Arch-010,3061 Sf 0.55�'/_ go 0.45� 0.4- t I t I l I �u-p?� � -Tc=-5.0-m rn LL 0.35-_ 4- 1 + 1 -4 I-1 W 4 1-4 I—I �-6 kf j _0.25�_I L- II I - I L L I I I-t L LIII -L _ 0.05 i 0- ........ .... .../.../.... ... .(.../.../:.../...�....,....1..../...,....,...., 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Existing 2019 07 02 Type /// 24-hr 2 Year Rainfall=3.20" Prepared by {enter your company name here) Printed 7/2/2019 HydroCADO 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 7 Summary for Subcatchment 2S: EDA-2 Runoff = 0.64 cfs @ 12.07 hrs, Volume= 0.050 af, Depth= 2.97" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Type III 24-hr 2 Year Rainfall=3.20" Area (sf) CN Description 501 98 Vehicular Pavement, HSG A 8,256 98 Roof, HSG A 8,757 98 Weighted Average 8,757 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, ROOFTOP (assume minimum Tc) Subcatchment 2S: EDA-2 Hydrograph 1 -4 T 1 T I T I--i r--i T -t 1 T T rt Runoff 0.65�-/ o.64 cfs T�e- I i �41h 0.6 I T 1 4- T-4 I T T 0.55�'z '� all- tafa�tl� 2�0' 0.5T_I TIT I T 7 T 1 T T T ROnTof -A"e 1$,757 0.45-:�/— T may!—If�Vp—lyrp-T �-P�-01 af 3 0.35� T T T T T TR ' �ep�hr ?T ` 0.3T — -TC=5.(Yl Ml i i —I �- 1 T T I 1--� I T I T 1 I—I �-6k=1 j 0.25�'Z 0.2� TTT �� T T TIT T T TTT 0.15: I TTT T TAT T TTT 0.1 0.05--�/ ° ............. .... .... ..../.... .... .... .... .... .... .... .... .... ... .... .... ....,....,....,,., 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Existing 2019 07 02 Type /// 24-hr 2 Year Rainfall=3.20" Prepared by {enter your company name here) Printed 7/2/2019 HydroCADO 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 8 Summary for Subcatchment 3S: EDA-3 Runoff = 0.94 cfs @ 12.07 hrs, Volume= 0.066 af, Depth= 2.26" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Type III 24-hr 2 Year Rainfall=3.20" Area (sf) CN Description 2,715 98 Vehicular Pavement, HSG A 155 98 Pedestrian Pavement, HSG A 7,778 98 Roof, HSG A 4,564 76 Steep Slope Landscape, HSG A 15,212 91 Weighted Average 4,564 30.00% Pervious Area 10,648 70.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 1.3 46 0.0037 0.60 Sheet Flow, Rear Parking Area Smooth surfaces n= 0.011 P2= 3.20" 0.2 41 0.3490 2.95 Shallow Concentrated Flow, Wooded slope behind bldg Woodland Kv= 5.0 fps 1.2 220 0.0440 3.15 Shallow Concentrated Flow, Overland Across Park Grassed Waterway Kv= 15.0 fps 2.3 Direct Entry, add 2.3 minutes to achieve min Tc=5.0 5.0 307 Total Subcatchment 3S: EDA-3 Hydrograph 1�/ ❑Runoff I I 0 94 cfs T��e II+ 24-hr I Year Rai nfall=3.2& Rluhdffl Area=15,212i sf R U ggff l yollu me�0-�OC61 o f Rulnpfl Pe,p�h�2� LL .?6'I, Flow Len th=307 TIcZ51.01 m i rIll o _ . 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Existing 2019 07 02 Type /// 24-hr 2 Year Rainfall=3.20" Prepared by {enter your company name here) Printed 7/2/2019 HydroCADO 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 9 Summary for Subcatchment 4S: EDA-4 Runoff = 0.10 cfs @ 12.08 hrs, Volume= 0.007 af, Depth= 1.27" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Type III 24-hr 2 Year Rainfall=3.20" Area (sf) CN Description 1,510 98 Vehicular Pavement, HSG A 604 98 Pedestrian Pavement, HSG A 891 32 Landscape, HSG A 3,005 78 Weighted Average 891 29.65% Pervious Area 2,114 70.35% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, (assume minimum Tc) Subcatchment 4S: EDA-4 Hydrograph 0.115!—I I t I --� 1 t—1 t I t 1-1 �—I t t I I—I t— I t I t Runoff 011 L/ � I T I � I I 0.10 cfs I� F7 17 T 1 e�11 i I 0.1 0.1-.1- 0.095 � 1 + 14 H 4 1� � L 0.085 0.08- ::1 1-1 R0111b"r"3,I00i sf 0.075'—I - 1 + 14 1 �1 4 1--] �� •p la w 0.065�— o 0A557 — t I t I - t-I - - - — gep�r9 U. 0.05- Tc -5.0-m i n 0.045 I T I � TFI F71 7 I ��T 0.04= — 0.035�— - - - - - - - - - - - °002%CI1 -�--' C I::I CI CI 0.015 0.01-/H I + I4 H Hi �1- I 0.005 i 0 W., ,..,..... .... 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Existing 2019 07 02 Type /// 24-hr 2 Year Rainfall=3.20" Prepared by {enter your company name here) Printed 7/2/2019 HydroCADO 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 10 Summary for Subcatchment 5S: EDA-5 Runoff = 0.27 cfs @ 12.07 hrs, Volume= 0.021 af, Depth= 2.97" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Type III 24-hr 2 Year Rainfall=3.20" Area (sf) CN Description 3,365 98 Vehicular Pavement, HSG A 254 98 Pedestrian Pavement, HSG A 3,619 98 Weighted Average 3,619 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, (assume minimum Tc) Subcatchment 5S: EDA-5 Hydrograph �_IIIIII11111IIII1IIlIII1— l ■Runoff 0.28-/_ L 1 L 1 L , 0.21 cfs 0.26LZ_ T / e I I i 2+41h-� 0.24�-/ 0.22L—I I + 1 1 L R0nbflf AO"--3,16--91 Sf 0.2 o.,B: —I L I T I I I I 1 1�� f 1°�1� �-I�•p � 0 0.14E L I t L L�u �p "7� o.12L_LL LI L IL C1 LI L 1L L1 L L IL L L 0.1 o.os: L I t 1 L �I fi I I� �I L rt I L 0.06E 0.04� 0.02-� rt 0 ,,, �.... .../..../.... �.�. .... .... ..../..../.... ......... ....�....,....,....,,., 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Existing 2019 07 02 Type /// 24-hr 2 Year Rainfall=3.20" Prepared by {enter your company name here) Printed 7/2/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 11 Summary for Link 6L: DP-5 Arlington Street EDA-5 Inflow Area = 0.083 ac,100.00% Impervious, Inflow Depth = 2.97" for 2 Year event Inflow = 0.27 cfs @ 12.07 hrs, Volume= 0.021 of Primary = 0.27 cfs @ 12.07 hrs, Volume= 0.021 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Link 6L: DP-5 Arlington Street EDA-5 Hydrograph ❑Inflow 0.28-:�/ 0.27 cfs ❑Primary 0.26 Inflow Area=G-.083 ac LI I IA IA 1-1 LI L 0.24I 0.22� - fi T I rt I 1 1-1 r I fi T I 0 I � � 14 1-4 1� � � � 1 - 0.18� � � � � � � u 0.16-�-/ 0 0.14� a 0.123'/ � + 0.1 - 0.08 I A I A 1-1 L L I - 1 1-1 rI TIT 0.04-:�/ 0.02-i'/ 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Existing 2019 07 02 Type /// 24-hr 2 Year Rainfall=3.20" Prepared by {enter your company name here) Printed 7/2/2019 HydroCADO 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 12 Summary for Link 7L: DP-4 Coolidge Hill Rd EDA-4 Inflow Area = 0.069 ac, 70.35% Impervious, Inflow Depth = 1.27" for 2 Year event Inflow = 0.10 cfs @ 12.08 hrs, Volume= 0.007 of Primary = 0.10 cfs @ 12.08 hrs, Volume= 0.007 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Link 7L: 1313-4 Coolidge Hill Rd EDA-4 — Hydrograph�—I I t I +I—f I� — C Inflow 0.115 I I I❑Primary 0.11 0.10 cfs 0.105 — 0.95 - -I - - - t-I - - - I- II -I - - 0.09 - - 0.085 0.08 � 0.675/ �I I fi l rt l I fi t I rt I� I� �I t- t I _ 0.07 — 0.065 c 0.055-/' — — — 0.045� i— — 00.04 0.03 i— — 0.025 0.02 0.015 0.01 0.005 0 /... .. 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Existing 2019 07 02 Type /// 24-hr 2 Year Rainfall=3.20" Prepared by {enter your company name here) Printed 7/2/2019 HydroCADO 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 13 Summary for Link 8L: DP-2 + DP-3 Filippello Park EDA-2 and EDA-3 Inflow Area = 0.550 ac, 80.96% Impervious, Inflow Depth = 2.52" for 2 Year event Inflow = 1.58 cfs @ 12.07 hrs, Volume= 0.115 of Primary = 1.58 cfs @ 12.07 hrs, Volume= 0.115 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Link 8L: DP-2 + DP-3 Filippello Park EDA-2 and EDA-3 Hydrograph I I I I I I I I I C Inflow 11.58 cfs ❑Primary infl6w Ar a-b.566 �� III IIIIIIIIIIIIIII � � IIIIIIIII " 1 � IIIIIIIIIIIIIII 3 0 LL 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Existing 2019 07 02 Type /// 24-hr 2 Year Rainfall=3.20" Prepared by {enter your company name here) Printed 7/2/2019 HydroCADO 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 14 Summary for Link 9L: DP-1 Exist Leach Basin EDA-1 Inflow Area = 0.237 ac,100.00% Impervious, Inflow Depth = 2.97" for 2 Year event Inflow = 0.76 cfs @ 12.07 hrs, Volume= 0.059 of Primary = 0.76 cfs @ 12.07 hrs, Volume= 0.059 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Link 9L: DP-1 Exist Leach Basin EDA-1 Hydrograph C Inflow �I 0.76 cfs �— — I❑Primary 0°5� I a" Ali-"-.2 0.6_ 0.5� '? 0.45-�/ 'I LI LIB I LITI -i I I L-] LI LIT c 0.4� LL0.35- ' - 1-I TIT IT IT IT TI TITI 0.3� — 0.25�-/ fiTrt 1- filrtlrt fiT 0.2� 0.15�-/ �� H 0.05fZ 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Existing 2019 07 02 Type /// 24-hr 10 Year Rainfall=4.90" Prepared by {enter your company name here) Printed 7/2/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Page 15 Time span=0.00-30.00 hrs, dt=0.02 hrs, 1501 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment 1 S: EDA-1 Runoff Area=10,306 sf 100.00% Impervious Runoff Depth=4.66" Tc=5.0 min CN=98 Runoff=1.17 cfs 0.092 of Subcatchment2S: EDA-2 Runoff Area=8,757 sf 100.00% Impervious Runoff Depth=4.66" Tc=5.0 min CN=98 Runoff=0.99 cfs 0.078 of Subcatchment3S: EDA-3 Runoff Area=15,212 sf 70.00% Impervious Runoff Depth=3.89" Flow Length=307' Tc=5.0 min CN=91 Runoff=1.57 cfs 0.113 of Subcatchment4S: EDA-4 Runoff Area=3,005 sf 70.35% Impervious Runoff Depth=2.63" Tc=5.0 min CN=78 Runoff=0.22 cfs 0.015 of Subcatchment5S: EDA-5 Runoff Area=3,619 sf 100.00% Impervious Runoff Depth=4.66" Tc=5.0 min CN=98 Runoff=0.41 cfs 0.032 of Link 6L: DP-5 Arlington Street EDA-5 Inflow=0.41 cfs 0.032 of Primary=0.41 cfs 0.032 of Link 7L: DP-4 Coolidge Hill Rd EDA-4 Inflow=0.22 cfs 0.015 of Primary=0.22 cfs 0.015 of Link 8L: DP-2+ DP-3 Filippello Park EDA-2 and EDA-3 Inflow=2.57 cfs 0.191 of Primary=2.57 cfs 0.191 of Link 9L: DP-1 Exist Leach Basin EDA-1 Inflow=1.17 cfs 0.092 of Primary=1.17 cfs 0.092 of Total Runoff Area = 0.939 ac Runoff Volume = 0.331 of Average Runoff Depth = 4.22" 13.34% Pervious = 0.125 ac 86.66% Impervious = 0.814 ac 19 Coolidge Hill Rd - Watertown Existing 2019 07 02 Type /// 24-hr 10 Year Rainfall=4.90" Prepared by {enter your company name here) Printed 7/2/2019 HydroCADO 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 16 Summary for Subcatchment 1S: EDA-1 Runoff = 1.17 cfs @ 12.07 hrs, Volume= 0.092 af, Depth= 4.66" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Type III 24-hr 10 Year Rainfall=4.90" Area (sf) CN Description 1,530 98 Vehicular Pavement, HSG A 8,776 98 Roof, HSG A 10,306 98 Weighted Average 10,306 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, ROOFTOP (assume minimum Tc) Subcatchment 1 S: EDA-1 Hydrograph �� i I I ❑Runoff I I I I I I I I I 1.17 cfs I I I I I �� T e 111 24-h r 1�1 -k- --k I—t �A - A -k- I1b *�aIII--k 611L-4.90" 1 1 1 ' I I Rluihdffl Area#110,13061 sf RUggfflVolpmp70.10�21 of Rulnpfl Pe,p�h74-66',' LL Tc=5.0 m i n IIIIII IIII � IIIIIII IIIIII IIII IIIII � o ..............i .,.._,....,....,....,....,.._,....,....,....,....,,., 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Existing 2019 07 02 Type /// 24-hr 10 Year Rainfall=4.90" Prepared by {enter your company name here) Printed 7/2/2019 HydroCADO 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 17 Summary for Subcatchment 2S: EDA-2 Runoff = 0.99 cfs @ 12.07 hrs, Volume= 0.078 af, Depth= 4.66" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Type III 24-hr 10 Year Rainfall=4.90" Area (sf) CN Description 501 98 Vehicular Pavement, HSG A 8,256 98 Roof, HSG A 8,757 98 Weighted Average 8,757 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, ROOFTOP (assume minimum Tc) Subcatchment 2S: EDA-2 Hydrograph �� i I I ❑Runoff 1�1 I T I T I� I o.99 cfs i T , ' I Type 24-hr I I I I 16 �(6aIIr Rain6ll=4.90" l l I Rt nbff Ate�08,17571 sf Ruggffl Violpmp70.10781 of 3 Rulnpfl Pe,p�h7�.66',' Tc=5.0 m i n IIIIII IIII � IIIIIII IIIIII IIII IIIII � i o ..............� .,.._,....,....,....,....,.._,....,....,....,....,,., 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Existing 2019 07 02 Type /// 24-hr 10 Year Rainfall=4.90" Prepared by {enter your company name here) Printed 7/2/2019 HydroCADO 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 18 Summary for Subcatchment 3S: EDA-3 Runoff = 1.57 cfs @ 12.07 hrs, Volume= 0.113 af, Depth= 3.89" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Type III 24-hr 10 Year Rainfall=4.90" Area (sf) CN Description 2,715 98 Vehicular Pavement, HSG A 155 98 Pedestrian Pavement, HSG A 7,778 98 Roof, HSG A 4,564 76 Steep Slope Landscape, HSG A 15,212 91 Weighted Average 4,564 30.00% Pervious Area 10,648 70.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 1.3 46 0.0037 0.60 Sheet Flow, Rear Parking Area Smooth surfaces n= 0.011 P2= 3.20" 0.2 41 0.3490 2.95 Shallow Concentrated Flow, Wooded slope behind bldg Woodland Kv= 5.0 fps 1.2 220 0.0440 3.15 Shallow Concentrated Flow, Overland Across Park Grassed Waterway Kv= 15.0 fps 2.3 Direct Entry, add 2.3 minutes to achieve min Tc=5.0 5.0 307 Total Subcatchment 3S: EDA-3 Hydrograph i i I i i ❑Runoff 1.57 cfs l l Teel ll+ 24!hr 110 Year Rainfall=4.90'I' Rluhdffl Area=15,212i sf I 1 1 + I-t -t +F�ugOf�Vloalumg=DO.1l 131-af w 1� IIIIII Runpfl Pe,p�h7 '119'I U- Flow Len th=307' TIcZ51.01 m i rII i 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Existing 2019 07 02 Type /// 24-hr 10 Year Rainfall=4.90" Prepared by {enter your company name here) Printed 7/2/2019 HydroCADO 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 19 Summary for Subcatchment 4S: EDA-4 Runoff = 0.22 cfs @ 12.08 hrs, Volume= 0.015 af, Depth= 2.63" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Type III 24-hr 10 Year Rainfall=4.90" Area (sf) CN Description 1,510 98 Vehicular Pavement, HSG A 604 98 Pedestrian Pavement, HSG A 891 32 Landscape, HSG A 3,005 78 Weighted Average 891 29.65% Pervious Area 2,114 70.35% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, (assume minimum Tc) Subcatchment 4S: EDA-4 L Hydrograph L 0.24 + Runoff 0.2� CI o.22 cfs I� �I �Tel� 0.21 0.2�� � 1 + I - 1 �I -+ I� � 0.19/— - 1 `� a�- a�fa�Cl� 0:;$%�I1 =' 1= =1rff�►re1 ,I01 s 0.16-- af w 00.15 .14 — - - - I - 1�1���1�M — 10-.p�51 0.12 FI � 1 T I �I I� �I �Ip�rn �lF 0 0.11 — -Tc=-5.011 in 009 fi fi I � III I� �I fi I� III 0.08 �I 14- 14 1 � IA �I � 14 1 A �I �0.07 1 4- 14 0.06�— - 0.05 0.04/�I fit — — — -I I- I— -I — - I— -I - I — I — 0.02�1 SIT I - 7 F I- I4 ' 0.01 / 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Existing 2019 07 02 Type /// 24-hr 10 Year Rainfall=4.90" Prepared by {enter your company name here) Printed 7/2/2019 HydroCADO 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 20 Summary for Subcatchment 5S: EDA-5 Runoff = 0.41 cfs @ 12.07 hrs, Volume= 0.032 af, Depth= 4.66" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Type III 24-hr 10 Year Rainfall=4.90" Area (sf) CN Description 3,365 98 Vehicular Pavement, HSG A 254 98 Pedestrian Pavement, HSG A 3,619 98 Weighted Average 3,619 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, (assume minimum Tc) Subcatchment 5S: EDA-5 Hydrograph 0.46--'/ I - �--I -L I 4 1-4 �—I L I Runoff 0.44- — 0.42 �I I o.41 cfs H 4- 14 1 T�e'Al i 2+4-h4 03: 6 -�I 0.32 �I - I� �—I R0rabfff-ArO.6=3,16a-91 Sf 0.3 0.28� � I + I � � �rP°f t 1° f •p w 0.26- — — 0.24 0.22%�I II _ = C— LL o1s T1 T 1T 1 T-I IA 4 1-4 �I 0.16- - �+ 0.12 0.1 o.08/CI LI I I � �I C C o.os-f'z— — 0.041. L — 0.02- 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Existing 2019 07 02 Type /// 24-hr 10 Year Rainfall=4.90" Prepared by {enter your company name here) Printed 7/2/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 21 Summary for Link 6L: DP-5 Arlington Street EDA-5 Inflow Area = 0.083 ac,100.00% Impervious, Inflow Depth = 4.66" for 10 Year event Inflow = 0.41 cfs @ 12.07 hrs, Volume= 0.032 of Primary = 0.41 cfs @ 12.07 hrs, Volume= 0.032 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Link 6L: DP-5 Arlington Street EDA-5 Hydrograph 0.46J � L ❑Inflow 0.44� � I � � � 0.41 cfs � �— � ❑Primary 0.42� _ In�lb�v A�i-6a-0.083 ac 0.38 T T 0.36. - 0.34t 0.32 0.3� -- rt — 0.28/ �I �I � III w 0.26 X — — 0.18: 0.16 — — 014� ,—I 4- 1 14 1-� �- + 14 1-t I--] + I - 0.12V — — 0.1 0.08/ �I �I fillrtI filfil � l� I� �I filrtl 0.06/ - - 0.04 0.02� 0 (... ..../.. .�.. .....:...................... 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Existing 2019 07 02 Type /// 24-hr 10 Year Rainfall=4.90" Prepared by {enter your company name here) Printed 7/2/2019 HydroCADO 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 22 Summary for Link 7L: DP-4 Coolidge Hill Rd EDA-4 Inflow Area = 0.069 ac, 70.35% Impervious, Inflow Depth = 2.63" for 10 Year event Inflow = 0.22 cfs @ 12.08 hrs, Volume= 0.015 of Primary = 0.22 cfs @ 12.08 hrs, Volume= 0.015 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Link 7L: 1313-4 Coolidge Hill Rd EDA-4 Hydrograph L gr L — t I t I — t I t I t I—f It t I t I C Inflow 0.24 i— ❑Primaryll 0.23/ / - :1: - - cfs —1101 - 0.22� � — 0.21/ fI t ± I _ t t I LI : t 1 0.2 0.18 �1 4- 1 1 - + 141-t I-] + I - 0.17 — 0.16 0.15 -1 FI 71 T I FI I� I� �I a 0.14 i— - - 30.12 - - - - - i_ - - - - - - - - - - o LL °0.1 1-1 4- 1 + 1 -' � � 14 1-4 1--] � � 1 - 0.09 0.08 0.07 ---11 E I T I T I D - T 17 1-1 1� D - T � 0.06 — — 0.05 - 0.04 �I I fi l l I - -t I- I -- -I I - - 0.03 0.02 0.01 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Existing 2019 07 02 Type /// 24-hr 10 Year Rainfall=4.90" Prepared by {enter your company name here) Printed 7/2/2019 HydroCADO 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 23 Summary for Link 8L: DP-2 + DP-3 Filippello Park EDA-2 and EDA-3 Inflow Area = 0.550 ac, 80.96% Impervious, Inflow Depth = 4.17" for 10 Year event Inflow = 2.57 cfs @ 12.07 hrs, Volume= 0.191 of Primary = 2.57 cfs @ 12.07 hrs, Volume= 0.191 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Link 8L: DP-2 + DP-3 Filippello Park EDA-2 and EDA-3 Hydrograph C Inflow I 2.57 cfs I❑Primary infl6w Ar a-b.566 �� IIIIIIIII 2 U 3 0 LL 1 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 2 ,,, ,,,, ,,,, ,,,, 0 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Existing 2019 07 02 Type /// 24-hr 10 Year Rainfall=4.90" Prepared by {enter your company name here) Printed 7/2/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 24 Summary for Link 9L: DP-1 Exist Leach Basin EDA-1 Inflow Area = 0.237 ac,100.00% Impervious, Inflow Depth = 4.66" for 10 Year event Inflow = 1.17 cfs @ 12.07 hrs, Volume= 0.092 of Primary = 1.17 cfs @ 12.07 hrs, Volume= 0.092 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Link 9L: 1313-1 Exist Leach Basin EDA-1 Hydrograph / ❑Inflow ❑Primary 1.17 cfs 1016w Area=0.237 ac I� I � N V 3 o - U- o './...�.�.�.�. ./...i...,. 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Existing 2019 07 02 Type /// 24-hr 25 Year Rainfall=6.20" Prepared by {enter your company name here) Printed 7/2/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Page 25 Time span=0.00-30.00 hrs, dt=0.02 hrs, 1501 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment 1 S: EDA-1 Runoff Area=10,306 sf 100.00% Impervious Runoff Depth=5.96" Tc=5.0 min CN=98 Runoff=1.48 cfs 0.118 of Subcatchment2S: EDA-2 Runoff Area=8,757 sf 100.00% Impervious Runoff Depth=5.96" Tc=5.0 min CN=98 Runoff=1.26 cfs 0.100 of Subcatchment3S: EDA-3 Runoff Area=15,212 sf 70.00% Impervious Runoff Depth=5.15" Flow Length=307' Tc=5.0 min CN=91 Runoff=2.06 cfs 0.150 of Subcatchment4S: EDA-4 Runoff Area=3,005 sf 70.35% Impervious Runoff Depth=3.76" Tc=5.0 min CN=78 Runoff=0.31 cfs 0.022 of Subcatchment5S: EDA-5 Runoff Area=3,619 sf 100.00% Impervious Runoff Depth=5.96" Tc=5.0 min CN=98 Runoff=0.52 cfs 0.041 of Link 6L: DP-5 Arlington Street EDA-5 Inflow=0.52 cfs 0.041 of Primary=0.52 cfs 0.041 of Link 7L: DP-4 Coolidge Hill Rd EDA-4 Inflow=0.31 cfs 0.022 of Primary=0.31 cfs 0.022 of Link 8L: DP-2+ DP-3 Filippello Park EDA-2 and EDA-3 Inflow=3.32 cfs 0.250 of Primary=3.32 cfs 0.250 of Link 9L: DP-1 Exist Leach Basin EDA-1 Inflow=1.48 cfs 0.118 of Primary=1.48 cfs 0.118 of Total Runoff Area = 0.939 ac Runoff Volume = 0.430 of Average Runoff Depth = 5.50" 13.34% Pervious = 0.125 ac 86.66% Impervious = 0.814 ac 19 Coolidge Hill Rd - Watertown Existing 2019 07 02 Type /// 24-hr 25 Year Rainfall=6.20" Prepared by {enter your company name here) Printed 7/2/2019 HydroCADO 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 26 Summary for Subcatchment 1S: EDA-1 Runoff = 1.48 cfs @ 12.07 hrs, Volume= 0.118 af, Depth= 5.96" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Type III 24-hr 25 Year Rainfall=6.20" Area (sf) CN Description 1,530 98 Vehicular Pavement, HSG A 8,776 98 Roof, HSG A 10,306 98 Weighted Average 10,306 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, ROOFTOP (assume minimum Tc) Subcatchment 1 S: EDA-1 Hydrograph �� i I I ❑Runoff 1.48 cfs] Type III 24-h r l l l 12� 1YeaIIr RaM611=6.20'i' Rluihdffl Alrea#110,13061 sf I-P�upOffj Vl-ollu�p-0•111sl of Rulnpfl Pe,p�h75.96',' LL Tc=5.0 m i n IIIIII IIII � IIIIIII IIIIII IIII IIIII � o �... ....,...,,....�... .�,....,....�...,;....,.. 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Existing 2019 07 02 Type /// 24-hr 25 Year Rainfall=6.20" Prepared by {enter your company name here) Printed 7/2/2019 HydroCADO 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 27 Summary for Subcatchment 2S: EDA-2 Runoff = 1.26 cfs @ 12.07 hrs, Volume= 0.100 af, Depth= 5.96" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Type III 24-hr 25 Year Rainfall=6.20" Area (sf) CN Description 501 98 Vehicular Pavement, HSG A 8,256 98 Roof, HSG A 8,757 98 Weighted Average 8,757 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, ROOFTOP (assume minimum Tc) Subcatchment 2S: EDA-2 Hydrograph _�� i I I ❑Runoff 1.26 cfs Type III 24-h r 12� 1Yea� Rain611=6.207 1�1 I Rt nbff Aee�08,17571 sf Ruggffl Violpmp70.11 Q01 of 3 Rulnpfl Pe,p�h75.96',' Tc=5.0 m i n - IIIIII IIII � IIIIIII IIIIII IIII IIIII � o �... ....,...,,....�... .�,....,....�...,;....,.. 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Existing 2019 07 02 Type /// 24-hr 25 Year Rainfall=6.20" Prepared by {enter your company name here) Printed 7/2/2019 HydroCADO 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 28 Summary for Subcatchment 3S: EDA-3 Runoff = 2.06 cfs @ 12.07 hrs, Volume= 0.150 af, Depth= 5.15" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Type III 24-hr 25 Year Rainfall=6.20" Area (sf) CN Description 2,715 98 Vehicular Pavement, HSG A 155 98 Pedestrian Pavement, HSG A 7,778 98 Roof, HSG A 4,564 76 Steep Slope Landscape, HSG A 15,212 91 Weighted Average 4,564 30.00% Pervious Area 10,648 70.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 1.3 46 0.0037 0.60 Sheet Flow, Rear Parking Area Smooth surfaces n= 0.011 P2= 3.20" 0.2 41 0.3490 2.95 Shallow Concentrated Flow, Wooded slope behind bldg Woodland Kv= 5.0 fps 1.2 220 0.0440 3.15 Shallow Concentrated Flow, Overland Across Park Grassed Waterway Kv= 15.0 fps 2.3 Direct Entry, add 2.3 minutes to achieve min Tc=5.0 5.0 307 Total Subcatchment 3S: EDA-3 Hydrograph i i I i ❑Runoff 2.06 cfs 2 Thy e-'11I 4 h�- 25 Year Rainfall=6.20'I' Rluhdffl Area=15,2121 sf Ruggffl Vlollume�0.11�01 of I_I 1 Runpf l �5�.�10W �ep�h n h= 7 LL 1 I I I I I I I I I I TIC�t 1.013m i 5 i 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Existing 2019 07 02 Type /// 24-hr 25 Year Rainfall=6.20" Prepared by {enter your company name here) Printed 7/2/2019 HydroCADO 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 29 Summary for Subcatchment 4S: EDA-4 Runoff = 0.31 cfs @ 12.07 hrs, Volume= 0.022 af, Depth= 3.76" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Type III 24-hr 25 Year Rainfall=6.20" Area (sf) CN Description 1,510 98 Vehicular Pavement, HSG A 604 98 Pedestrian Pavement, HSG A 891 32 Landscape, HSG A 3,005 78 Weighted Average 891 29.65% Pervious Area 2,114 70.35% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, (assume minimum Tc) Subcatchment 4S: EDA-4 Hydrograph �I � I I-] kI � I 4 I-4 Ti � I -4 0.34%� 0.31 cfs 0.3� L ■Runoff 0.32� - 'T�p e� 24 h� [0.28 0.26 0.24 fi rt -1 r-I RO nD""e 13,10051 s-f — — — — — — — — — — — — — — 0.22� j- 1 + -j I pyr�qffypl�jr"1 Y.P�21 af w 0.2 0.18 Iu� r LL 0.16� -Tc-5.W 11 M 0.12�1/ 0.1�-/ L1I 1 - 1 L _ 11 LI - 11-1 ❑ L_ 1 I1 -L o.os 0.06� - - - - - - - - - - - - 0.04-�/ t 0.02� t— I o 6... ........I 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Existing 2019 07 02 Type /// 24-hr 25 Year Rainfall=6.20" Prepared by {enter your company name here) Printed 7/2/2019 HydroCADO 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 30 Summary for Subcatchment 5S: EDA-5 Runoff = 0.52 cfs @ 12.07 hrs, Volume= 0.041 af, Depth= 5.96" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Type III 24-hr 25 Year Rainfall=6.20" Area (sf) CN Description 3,365 98 Vehicular Pavement, HSG A 254 98 Pedestrian Pavement, HSG A 3,619 98 Weighted Average 3,619 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, (assume minimum Tc) Subcatchment 5S: EDA-5 Hydrograph _� IIIIIIIIIIIIII � III ❑Runoff 0.52 cfs - 0.5�1/ lye 124-h r 0.45_�/— 2 `�e�a� a�fa111� 2Q'r 0.4 — �nfff ►r�� ,6�I 9 S 3 0 3-i�/ LL 0.25� Tc .�m i n 0.2_:�/ 0.05�z O � ..............(.... .... .... ....(....(....(....�.�.. .... .... .... .... ....,.... .... ....,....,....,,., 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Existing 2019 07 02 Type /// 24-hr 25 Year Rainfall=6.20" Prepared by {enter your company name here) Printed 7/2/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 31 Summary for Link 6L: DP-5 Arlington Street EDA-5 Inflow Area = 0.083 ac,100.00% Impervious, Inflow Depth = 5.96" for 25 Year event Inflow = 0.52 cfs @ 12.07 hrs, Volume= 0.041 of Primary = 0.52 cfs @ 12.07 hrs, Volume= 0.041 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Link 6L: DP-5 Arlington Street EDA-5 Hydrograph ❑Inflow ❑Primary 0.55� 0.52 cfs Inflow Area=0.083 ac 0.45�z 0.43 0.35-�/ _ N 0 2� 0.15-�/ 0.1� �I — 0.05-�/ 0 .�.. .....:...................... 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Existing 2019 07 02 Type /// 24-hr 25 Year Rainfall=6.20" Prepared by {enter your company name here) Printed 7/2/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 32 Summary for Link 7L: DP-4 Coolidge Hill Rd EDA-4 Inflow Area = 0.069 ac, 70.35% Impervious, Inflow Depth = 3.76" for 25 Year event Inflow = 0.31 cfs @ 12.07 hrs, Volume= 0.022 of Primary = 0.31 cfs @ 12.07 hrs, Volume= 0.022 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Link 7L: DP-4 Coolidge Hill Rd EDA-4 Hydrograph � I + 14 I--1 N ❑ 0.34� 0.31 CfSb !'11 ���� � Prima Primaryll 0.32�/ I111 a _ 0.3� 0.28 L 11J 1- —j L L 11 - _ 0.26-;:,/ ' 0.24-�/ 'I L L I L I L IL L L L I L IL IL L L L I - 0.22-�/ /I TI 71 T 17 I- 7 T T I T IT IT TI T I T I - N 0.2-�/ — � 0.18� -1 t 71 fi � rt fi l l LL0.14�-/ firtrt fifirt fifi 0.12-�'/ 0.08� �I �I � I � I o.os_ 0.04_ 0.02�'X 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Existing 2019 07 02 Type /// 24-hr 25 Year Rainfall=6.20" Prepared by {enter your company name here) Printed 7/2/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 33 Summary for Link 8L: DP-2 + DP-3 Filippello Park EDA-2 and EDA-3 Inflow Area = 0.550 ac, 80.96% Impervious, Inflow Depth = 5.45" for 25 Year event Inflow = 3.32 cfs @ 12.07 hrs, Volume= 0.250 of Primary = 3.32 cfs @ 12.07 hrs, Volume= 0.250 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Link 8L: DP-2 + DP-3 Filippello Park EDA-2 and EDA-3 Hydrograph / ❑Inflow ❑Primary 3.32 cfs Infl6w Area=0.550 ac 3- N u 2 3 - 0 L 1- 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Existing 2019 07 02 Type /// 24-hr 25 Year Rainfall=6.20" Prepared by {enter your company name here) Printed 7/2/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 34 Summary for Link 9L: DP-1 Exist Leach Basin EDA-1 Inflow Area = 0.237 ac,100.00% Impervious, Inflow Depth = 5.96" for 25 Year event Inflow = 1.48 cfs @ 12.07 hrs, Volume= 0.118 of Primary = 1.48 cfs @ 12.07 hrs, Volume= 0.118 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Link 9L: 1313-1 Exist Leach Basin EDA-1 Hydrograph / ❑Inflow ❑Primary 1.48 cfs W16W6 Area=0.237 ac 1— N V 3 - 0 LL 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Existing 2019 07 02Type /// 24-hr 100 Year Rainfall=8.90" Prepared by {enter your company name here) Printed 7/2/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Page 35 Time span=0.00-30.00 hrs, dt=0.02 hrs, 1501 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment 1 S: EDA-1 Runoff Area=10,306 sf 100.00% Impervious Runoff Depth=8.66" Tc=5.0 min CN=98 Runoff=2.14 cfs 0.171 of Subcatchment2S: EDA-2 Runoff Area=8,757 sf 100.00% Impervious Runoff Depth=8.66" Tc=5.0 min CN=98 Runoff=1.81 cfs 0.145 of Subcatchment3S: EDA-3 Runoff Area=15,212 sf 70.00% Impervious Runoff Depth=7.81" Flow Length=307' Tc=5.0 min CN=91 Runoff=3.04 cfs 0.227 of Subcatchment4S: EDA-4 Runoff Area=3,005 sf 70.35% Impervious Runoff Depth=6.23" Tc=5.0 min CN=78 Runoff=0.51 cfs 0.036 of Subcatchment5S: EDA-5 Runoff Area=3,619 sf 100.00% Impervious Runoff Depth=8.66" Tc=5.0 min CN=98 Runoff=0.75 cfs 0.060 of Link 6L: DP-5 Arlington Street EDA-5 Inflow=0.75 cfs 0.060 of Primary=0.75 cfs 0.060 of Link 7L: DP-4 Coolidge Hill Rd EDA-4 Inflow=0.51 cfs 0.036 of Primary=0.51 cfs 0.036 of Link 8L: DP-2+ DP-3 Filippello Park EDA-2 and EDA-3 Inflow=4.86 cfs 0.372 of Primary=4.86 cfs 0.372 of Link 9L: DP-1 Exist Leach Basin EDA-1 Inflow=2.14 cfs 0.171 of Primary=2.14 cfs 0.171 of Total Runoff Area = 0.939 ac Runoff Volume = 0.639 of Average Runoff Depth = 8.17" 13.34% Pervious = 0.125 ac 86.66% Impervious = 0.814 ac 19 Coolidge Hill Rd - Watertown Existing 2019 07 02Type /// 24-hr 100 Year Rainfall=8.90" Prepared by {enter your company name here) Printed 7/2/2019 HydroCADO 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 36 Summary for Subcatchment 1S: EDA-1 Runoff = 2.14 cfs @ 12.07 hrs, Volume= 0.171 af, Depth= 8.66" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Type III 24-hr 100 Year Rainfall=8.90" Area (sf) CN Description 1,530 98 Vehicular Pavement, HSG A 8,776 98 Roof, HSG A 10,306 98 Weighted Average 10,306 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, ROOFTOP (assume minimum Tc) Subcatchment 1 S: EDA-1 Hydrograph 2.14 cfs I I I I � 1 Ty e'11-24-h� i0b �Y�al- Rairif�11=8.90'1' Rluihdffl Area#110,13061 sf RuggfflVlol,um�70.11711 of 3 Rulnpfl Pe,p�h78.66'I -Tc=5.0-min LL IIIIII IIII IIIIII 1� IIIIII IIII IIIIIIII IIIIII IIII IIIII � o �.... ......... ....... �... ....,...,,....�... .�,....,....�... 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Existing 2019 07 02Type /// 24-hr 100 Year Rainfall=8.90" Prepared by {enter your company name here) Printed 7/2/2019 HydroCADO 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 37 Summary for Subcatchment 2S: EDA-2 Runoff = 1.81 cfs @ 12.07 hrs, Volume= 0.145 af, Depth= 8.66" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Type III 24-hr 100 Year Rainfall=8.90" Area (sf) CN Description 501 98 Vehicular Pavement, HSG A 8,256 98 Roof, HSG A 8,757 98 Weighted Average 8,757 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, ROOFTOP (assume minimum Tc) Subcatchment 2S: EDA-2 Hydrograph + 2 ❑Runoff 1.81 cfs Type l III 24-h r i0b �Yaal- Rainfall=8.90" Rtnbff Ate&�8,7571 sf RUggffl ViOI,ump70.11451 of 3 1 ' Run ��hj.01"'-, Tc=5.0 m i n - IIIIII IIII � IIIIIII IIIIII IIII IIIII � i o �.... ......... ....... �... ....,...,,....�... .�,....,....�... 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Existing 2019 07 02Type /// 24-hr 100 Year Rainfall=8.90" Prepared by {enter your company name here) Printed 7/2/2019 HydroCADO 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 38 Summary for Subcatchment 3S: EDA-3 Runoff = 3.04 cfs @ 12.07 hrs, Volume= 0.227 af, Depth= 7.81" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Type III 24-hr 100 Year Rainfall=8.90" Area (sf) CN Description 2,715 98 Vehicular Pavement, HSG A 155 98 Pedestrian Pavement, HSG A 7,778 98 Roof, HSG A 4,564 76 Steep Slope Landscape, HSG A 15,212 91 Weighted Average 4,564 30.00% Pervious Area 10,648 70.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 1.3 46 0.0037 0.60 Sheet Flow, Rear Parking Area Smooth surfaces n= 0.011 P2= 3.20" 0.2 41 0.3490 2.95 Shallow Concentrated Flow, Wooded slope behind bldg Woodland Kv= 5.0 fps 1.2 220 0.0440 3.15 Shallow Concentrated Flow, Overland Across Park Grassed Waterway Kv= 15.0 fps 2.3 Direct Entry, add 2.3 minutes to achieve min Tc=5.0 5.0 307 Total Subcatchment 3S: EDA-3 Hydrograph �I � � III III . . IIIIII ❑Runoff 3.04 cfs 3 - I� Thy et'lI 4 h�- 1 100 Year Rainfall=8.90'I' Rluhdffl Area=15,212i sf 2 � T�IUI Q�IVIoilume�• 71a Rulnpfl Pe,p�h77.11 ,, LL Flow Len th=307 TIc-51.01 m i rIll IIII I � ' III � ' o �.. 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Existing 2019 07 02Type /// 24-hr 100 Year Rainfall=8.90" Prepared by {enter your company name here) Printed 7/2/2019 HydroCADO 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 39 Summary for Subcatchment 4S: EDA-4 Runoff = 0.51 cfs @ 12.07 hrs, Volume= 0.036 af, Depth= 6.23" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Type III 24-hr 100 Year Rainfall=8.90" Area (sf) CN Description 1,510 98 Vehicular Pavement, HSG A 604 98 Pedestrian Pavement, HSG A 891 32 Landscape, HSG A 3,005 78 Weighted Average 891 29.65% Pervious Area 2,114 70.35% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, (assume minimum Tc) Subcatchment 4S: EDA-4 Hydrograph 0.55� + 4- 1 Runoff I � 1 + 1 4 1 o.5l cfs] I� P 4 1 �� T- � e I I 1 2+4-fi� 0.45-�/ fi rt rt �0�`�e�a�- Fta�f11� 90' 0.4�-' IRUnbff AOeA=13,0051 sf 0.35�'/ Ryggff Vplymp=lO.p�61 a# 3 0.3-�/— L I L I � L L L � 0.25 � C= min -I �- I 0.2-�/ 01�7 TI T I7 7 T T I—f FI T- 0.05-�/ 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Existing 2019 07 02Type /// 24-hr 100 Year Rainfall=8.90" Prepared by {enter your company name here) Printed 7/2/2019 HydroCADO 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 40 Summary for Subcatchment 5S: EDA-5 Runoff = 0.75 cfs @ 12.07 hrs, Volume= 0.060 af, Depth= 8.66" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Type III 24-hr 100 Year Rainfall=8.90" Area (sf) CN Description 3,365 98 Vehicular Pavement, HSG A 254 98 Pedestrian Pavement, HSG A 3,619 98 Weighted Average 3,619 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, (assume minimum Tc) Subcatchment 5S: EDA-5 Hydrograph LI I I -i LI -L I � I� �I � I � �I LI ■Runoff 0 8� T 0.75 cfs -1 � T T 1- 0.75= _ T�e-Tfllli �4-h °' 0.6�-/_ 1-1 P ftrabfff-AO"=-3,16"1 Sf 0.55-�Z 0.5�-/_ L L I �}�off-Vptul rpj�--G•pQ u 0.45: 0.4-> fi I T rt "�'Q 4 p 'r �►�r LL oo3�-I � I + 1 - 1 I I- 1-1 �1 4- I4 1-f H� _ _ N= 0.25�'/ - 0.2-�'/0.15�-/_ T 1 1 17 1 11 T T 1 F ' 0.1 _ 0.051'/ 0 .................(.... .... .... ....(....(....(.... .......,....,....,....,......... .... ....,....,....,,., 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Existing 2019 07 02Type /// 24-hr 100 Year Rainfall=8.90" Prepared by {enter your company name here) Printed 7/2/2019 HydroCADO 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 41 Summary for Link 6L: DP-5 Arlington Street EDA-5 Inflow Area = 0.083 ac,100.00% Impervious, Inflow Depth = 8.66" for 100 Year event Inflow = 0.75 cfs @ 12.07 hrs, Volume= 0.060 of Primary = 0.75 cfs @ 12.07 hrs, Volume= 0.060 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Link 6L: 1313-5 Arlington Street EDA-5 Hydrograph i J I I I i i i i i i I I — C Inflow 08 � J 0.75 cfs — 3 1 T T T I❑Primary 0.75�- Inlrr A�i- - b� 0.7- tI fiITlrt TI 0.65-�/ 0.6 MITI - � T7 H � � - 0.55 0.5-�/ T 17 I-4 I--] 1 - � 0.45�-' c 0.4� LL0.35- ' FI 71T1 TI 7T17 1-1 1-1 7 MITI 0.3� 0.25-�/ fi1T fiTrt fiT 0.2_ 0.15_ 0.05-�Z 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Existing 2019 07 02Type /// 24-hr 100 Year Rainfall=8.90" Prepared by {enter your company name here) Printed 7/2/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 42 Summary for Link 7L: DP-4 Coolidge Hill Rd EDA-4 Inflow Area = 0.069 ac, 70.35% Impervious, Inflow Depth = 6.23" for 100 Year event Inflow = 0.51 cfs @ 12.07 hrs, Volume= 0.036 of Primary = 0.51 cfs @ 12.07 hrs, Volume= 0.036 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Link 7L: DP-4 Coolidge Hill Rd EDA-4 Hydrograph ❑Inflow 0.55-�'/ 0.51 cfs ❑Primary 05 Inflow Area=0.069 ac 0.45-�/ 0.4�'/ 0.35-�'/ �I N 0.3-�/ 3 = o � 0.25_ t—I 7 0.2-�/ — 0.15�z 0.1 0.05- o /...,� ,/../. .,,... 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Existing 2019 07 02Type /// 24-hr 100 Year Rainfall=8.90" Prepared by {enter your company name here) Printed 7/2/2019 HydroCADO 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 43 Summary for Link 8L: DP-2 + DP-3 Filippello Park EDA-2 and EDA-3 Inflow Area = 0.550 ac, 80.96% Impervious, Inflow Depth = 8.12" for 100 Year event Inflow = 4.86 cfs @ 12.07 hrs, Volume= 0.372 of Primary = 4.86 cfs @ 12.07 hrs, Volume= 0.372 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Link 8L: DP-2 + DP-3 Filippello Park EDA-2 and EDA-3 Hydrograph i I I I I I i I I I I I I I❑Pnmary� 4.86 cfs - 5 �nfl�wI AraI-b.566 �� I--I LI LI III I- 4 IIIIIII IIIIIIIIIIII " 3 IIIIIIIII 3 0 LL � IIIIIIIIIIIIl ' 2 III I IIIIIIIII 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Existing 2019 07 02Type /// 24-hr 100 Year Rainfall=8.90" Prepared by {enter your company name here) Printed 7/2/2019 HydroCADO 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 44 Summary for Link 9L: DP-1 Exist Leach Basin EDA-1 Inflow Area = 0.237 ac,100.00% Impervious, Inflow Depth = 8.66" for 100 Year event Inflow = 2.14 cfs @ 12.07 hrs, Volume= 0.171 of Primary = 2.14 cfs @ 12.07 hrs, Volume= 0.171 af, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Link 9L: DP-1 Exist Leach Basin EDA-1 Hydrograph Illll11ll11llli11111llllll C Inflow 2.14 cfs " Primary ll - �n#I�nr �►r�a�.23f�c� 2-� III III IIIIIIIIIIIIIII - III III IIIIIIIIIIII III III IIIIIIIIIIIIIII I- 3 0 " 1�� I IIIIIIIIIIIIIII 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) STORMWATER REPORT CROWE July 09, 2019 Landscape Architects and Civil Engineers 19 Coolidge Hill Road Winchester, Massachusetts Watertown, Massachusetts PROPOSED CONDITIONS HYDROCAD CALCS 21 (i� Discharge to DP-4 at DP-4: Surcharge Zero Round Leaching Coolidge Hill Road PDA-4 Landscape along Elev.42.25 Structure 01 Eliminated CHR 5S 1S 2S PDA-5 Arlington reet PDA-1 4.9k f Roof,Veh. Public Pedestrian ' e P -2 10ksf Roof Area Paving, SI pe,&Edge Land.cape Discharge to DP-5 at Discharges to DP-2 and Arlington Street DP-3 Filippello Park Eliminated Eliminated V 2OL gP 3S DPs-1, 2, 3, &5: CB Underground Chambers PDA-3 Pocket Park and Rim near Arlington St. 0 Retention for PDAs-1, Abutter Surcharge Elev.36.00 2,3, &5 Subcat Reach On Link Routing Diagram for 19 Coolidge Hill Rd-Watertown Proposed 2019 07 0 Prepared by{enter your company name here}, Printed 8/13/2019 HydroCAD®10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC 19 Coolidge Hill Rd - Watertown Proposed 2019 07 02 Prepared by {enter your company name here) Printed 8/13/2019 HvdroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Page 2 Area Listing (all nodes) Area CN Description (acres) (subcatchment-numbers) 0.218 32 Landscape, Good, HSG A (1 S, 3S, 4S, 5S) 0.114 98 Pedestrian Pavement, HSG A (1S, 3S, 4S, 5S) 0.374 98 Roof, HSG A (1S, 2S, 3S) 0.049 76 Steep Landscape, Good, HSG A (1S) 0.184 98 Vehicular Pavement, HSG A (1 S) 0.939 82 TOTAL AREA 19 Coolidge Hill Rd - Watertown Proposed 2019 07 02 Prepared by {enter your company name here) Printed 8/13/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Page 3 Soil Listing (all nodes) Area Soil Subcatchment (acres) Group Numbers 0.939 HSG A 1 S, 2S, 3S, 4S, 5S 0.000 HSG B 0.000 HSG C 0.000 HSG D 0.000 Other 0.939 TOTAL AREA 19 Coolidge Hill Rd - Watertown Proposed 2019 07 02 Prepared by {enter your company name here) Printed 8/13/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Page 4 Ground Covers (all nodes) HSG-A HSG-B HSG-C HSG-D Other Total Ground Subcatchment (acres) (acres) (acres) (acres) (acres) (acres) Cover Numbers 0.218 0.000 0.000 0.000 0.000 0.218 Landscape, Good 1 S, 3S, 4S, 5S 0.114 0.000 0.000 0.000 0.000 0.114 Pedestrian Pavement 1 S, 3S, 4S, 5S 0.374 0.000 0.000 0.000 0.000 0.374 Roof 1 S, 2S, 3S 0.049 0.000 0.000 0.000 0.000 0.049 Steep Landscape, Good is 0.184 0.000 0.000 0.000 0.000 0.184 Vehicular Pavement is 0.939 0.000 0.000 0.000 0.000 0.939 TOTAL AREA 19 Coolidge Hill Rd - Watertown Proposed 2019 07 02 Type /// 24-hr 2 Year Rainfall=3.20" Prepared by {enter your company name here) Printed 8/13/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Page 5 Time span=0.00-30.00 hrs, dt=0.02 hrs, 1501 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment IS: PDA-1 4.9ksf Roof,Veh. Runoff Area=18,002 sf 82.67% Impervious Runoff Depth=2.35" Tc=5.0 min CN=92 Runoff=1.15 cfs 0.081 of Subcatchment2S: PDA-2 10ksf Roof Runoff Area=10,000 sf 100.00% Impervious Runoff Depth=2.97" Tc=5.0 min CN=98 Runoff=0.74 cfs 0.057 of Subcatchment3S: PDA-3 Pocket Park and Runoff Area=8,109 sf 31.64% Impervious Runoff Depth=0.20" Tc=5.0 min CN=53 Runoff=0.01 cfs 0.003 of Subcatchment4S: PDA-4 Landscape along Runoff Area=2,539 sf 5.00% Impervious Runoff Depth=0.00" Tc=5.0 min CN=35 Runoff=0.00 cfs 0.000 of Subcatchment SS: PDA-5 Arlington Street Runoff Area=2,249 sf 75.72% Impervious Runoff Depth=1.54" Tc=5.0 min CN=82 Runoff=0.10 cfs 0.007 of Pond 8P: Underground Chambers Retention Peak EIev=30.28' Storage=886 cf Inflow=1.98 cfs 0.147 of Outflow=0.69 cfs 0.147 of Pond 10P: Round Leaching Structure 01 Peak EIev=36.00' Storage=0 cf Inflow=0.00 cfs 0.000 of Outflow=0.00 cfs 0.000 of Link 20L: DPs-1,2, 3, & 5: CB Rim near Arlington St. 0 Surcharge Elev.36.00 Primary=0.00 cfs 0.000 of Link 21 L: DP-4: Surcharge Zero Elev.42.25 Primary=0.00 cfs 0.000 of Total Runoff Area = 0.939 ac Runoff Volume = 0.147 of Average Runoff Depth = 1.88" 28.41% Pervious = 0.267 ac 71.59% Impervious = 0.672 ac 19 Coolidge Hill Rd - Watertown Proposed 2019 07 02 Type /// 24-hr 2 Year Rainfall=3.20" Prepared by {enter your company name here) Printed 8/13/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 6 Summary for Subcatchment 1 S: PDA-1 4.9ksf Roof, Veh. Paving, Slope,& Edge Landscape Runoff = 1.15 cfs @ 12.07 hrs, Volume= 0.081 af, Depth= 2.35" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Type III 24-hr 2 Year Rainfall=3.20" Area (sf) CN Description 8,035 98 Vehicular Pavement, HSG A 1,947 98 Pedestrian Pavement, HSG A 2,120 76 Steep Landscape, Good, HSG A 1,000 32 Landscape, Good, HSG A 4,900 98 Roof, HSG A 18,002 92 Weighted Average 3,120 17.33% Pervious Area 14,882 82.67% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, (assume minimum Tc) Subcatchment 1S: PDA-1 4.9ksf Roof, Veh. Paving, Slope,& Edge Landscape Hydrograph I I I i I I I I ❑Runoff I 1.15 cfs Y� �h r� Ty e l l l 24- �aIr-h"i fal1=12V' Rluihdffl Alyda#118,10021 sf Ruggffl V1ol1uTp70.10$11 of 3 1 1 1 1 1 1 RulnpflPep�h7F.�T'1 LL Tc=5.0 m i n - IIII ' IIIIIIII 0 ................................ ..... ........ .. .�,....... . :. 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Proposed 2019 07 02 Type /// 24-hr 2 Year Rainfall=3.20" Prepared by {enter your company name here) Printed 8/13/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 7 Summary for Subcatchment 2S: PDA-2 10ksf Roof Runoff = 0.74 cfs @ 12.07 hrs, Volume= 0.057 af, Depth= 2.97" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Type III 24-hr 2 Year Rainfall=3.20" Area (sf) CN Description 10,000 98 Roof, HSG A 10,000 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, (assume minimum Tc) Subcatchment 2S: PDA-2 10ksf Roof Hydrograph I - ITI4 HI 4 I--] P KITH ITI4 0'$-�'/ — 0.74 cfs ■Runoff o0 7�-I L I T I � U L I - T 1-Tel 11 241 h� 0.65� TIT T T --1 T L 'i � f�QII Ifll� 2�� 0 55�-I +- 1 T 14 1 �-1 4 11111-trrhoff Ifid*aO1-IG,I0001 Sf 00.4�' T I T 1 T T' TI �uPr �-!P�h "/+ ml 0.3�'-I t I T I T 1� I-I � fi 0.25?/ S I T 14 1 1 A �-1 T 1 A S I T 14 0.2�-/ 0.15� 0.05_ o �....r:. /... ...�;:. ...i.. .... .... ...,....,....,.... 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Proposed 2019 07 02 Type /// 24-hr 2 Year Rainfall=3.20" Prepared by {enter your company name here) Printed 8/13/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 8 Summary for Subcatchment 3S: PDA-3 Pocket Park and Abutter Runoff = 0.01 cfs @ 12.37 hrs, Volume= 0.003 af, Depth= 0.20" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Type III 24-hr 2 Year Rainfall=3.20" Area (sf) CN Description 1,172 98 Pedestrian Pavement, HSG A 1,394 98 Roof, HSG A 5,543 32 Landscape, Good, HSG A 8,109 53 Weighted Average 5,543 68.36% Pervious Area 2,566 31.64% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, (assume minimum Tc) Subcatchment 3S: PDA-3 Pocket Park and Abutter Hydrograph 0.014-/` I I I I I r—I -I-- � I I L _ _ _ _ _ _ _ O Runoff 0.013: LI L I 1 11 L 0.01 cfs J L I L I -TYp e 11 2�1h� 0.012 0.011� — fi � _ efir� lai�fa�1T�320 0.01�_I I I I I I L I 1 1 IRUnbff Arley=811091 sf 0.009 + �-ur�offfVQiuMA�= cl� 0.008�'/ 3 0.007 —I l l l l l l I ' �_'�1' 7 r 0�� a 0.006� Tc--,5-.0-m1ry 0005J,-1 � I + I � H H I� �I L I4 I � 0.004�-/ T I J I T T 0.003-�'// 0.002-�'/ — 0.001-�'/ IT TI I -T 0 /.. .. .. ../....� .,. 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Proposed 2019 07 02 Type /// 24-hr 2 Year Rainfall=3.20" Prepared by {enter your company name here) Printed 8/13/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 9 Summary for Subcatchment 4S: PDA-4 Landscape along CHR Runoff = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af, Depth= 0.00" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Type III 24-hr 2 Year Rainfall=3.20" Area (sf) CN Description 127 98 Pedestrian Pavement, HSG A 2,412 32 Landscape, Good, HSG A 2,539 35 Weighted Average 2,412 95.00% Pervious Area 127 5.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, (assume minimum Tc) Subcatchment 4S: PDA-4 Landscape along CHR Hydrograph 1 � i I i I �Runoff �T��el ll+ 24!hr Year Rainfall=3.2& R06off Arrea=12,539i sf Ruggffl Vlollulne70.10401 of 3 1 1 1 1 1 1 Ri ulnpf14elp�hrQ-01°' Tc=5.0 m i n 1 1 1 1 1 I 116NI =13� I IIIIIIIII � � IIIIII IIIIIIIII liii 0.00 cfs 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Proposed 2019 07 02 Type /// 24-hr 2 Year Rainfall=3.20" Prepared by {enter your company name here) Printed 8/13/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 10 Summary for Subcatchment 5S: PDA-5 Arlington Street Public Pedestrian Bike Area Runoff = 0.10 cfs @ 12.08 hrs, Volume= 0.007 af, Depth= 1.54" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Type III 24-hr 2 Year Rainfall=3.20" Area (sf) CN Description 1,703 98 Pedestrian Pavement, HSG A 546 32 Landscape, Good, HSG A 2,249 82 Weighted Average 546 24.28% Pervious Area 1,703 75.72% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, (assume minimum Tc) Subcatchment 5S: PDA-5 Arlington Street Public Pedestrian Bike Area Hydrograph —� t l 1 CI I I -� I-i CI i- I -� I-i I -I C I + 0.105- — ■Runoff 0.1_/ 0.10 cfs 0.095� - fi C - C - - �T e 0.09 0.085-/C C C C I-1 C C IC CI 0.08=/_ _ _ 0.075=/-I �- I � 1 - 1 C I� C 1 R0 bff-Arley 2,2 91 Sf 0.07 0.065' � 1 � C 1 4 N Rpf 1�rnC� .p a w 0.06- 30.055Ch - 1 t I -i C C u �� �, `0 0 05 0.045 TC=5.0-11 m - 0.04 Cfirtrt C CfirtCC - Ise 0.035�C1 CI C IC CI Cl CI CI C 1C CI C1 C 1C 0.03= 0.025 / 0.02�C1 � 1 14 CI I� C 4 1� C C I 14 0.015- 0.01CC1 C S C C1 � 4 1-4 CI C I + I - 0.005C / i 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Proposed 2019 07 02 Type /// 24-hr 2 Year Rainfall=3.20" Prepared by {enter your company name here) Printed 8/13/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Page 11 Summary for Pond 8P: Underground Chambers Retention for PDAs-1, 2, 3, & 5 Inflow Area = 0.881 ac, 75.99% Impervious, Inflow Depth = 2.01" for 2 Year event Inflow = 1.98 cfs @ 12.07 hrs, Volume= 0.147 of Outflow = 0.69 cfs @ 12.34 hrs, Volume= 0.147 af, Atten= 65%, Lag= 16.1 min Discarded = 0.69 cfs @ 12.34 hrs, Volume= 0.147 of Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Peak Elev= 30.28' @ 12.34 hrs Surf.Area= 3,357 sf Storage= 886 cf Plug-Flow detention time= 6.2 min calculated for 0.147 of(100% of inflow) Center-of-Mass det. time= 6.2 min ( 792.5 - 786.3 ) Volume Invert Avail.Storage Storaqe Description #1A 29.70' 2,967 cf 34.75'W x 96.59'L x 3.50'H Field A 11,748 cf Overall -4,330 cf Embedded = 7,418 cf x 40.0% Voids #2A 30.20' 4,330 cf Lane Storm Keeper SK75 x 91 Inside#1 Effective Size= 44.7"W x 30.0"H => 6.61 sf x 7.081 = 46.8 cf Overall Size= 51.0"W x 30.0"H x 7.30'L with 0.22' Overlap 91 Chambers in 7 Rows Cap Storaqe= +5.2 cf x 2 x 7 rows = 73.4 cf 7,297 cf Total Available Storage Storage Group A created with Chamber Wizard Device Routinq Invert Outlet Devices #1 Discarded 29.70' 8.270 in/hr Exfiltration over Horizontal area Conductivity to Groundwater Elevation = 21.00' Discarded OutFlow Max=0.69 cfs @ 12.34 hrs HW=30.28' (Free Discharge) L1=Exfiltration ( Controls 0.69 cfs) 19 Coolidge Hill Rd - Watertown Proposed 2019 07 02 Type /// 24-hr 2 Year Rainfall=3.20" Prepared by {enter your company name here) Printed 8/13/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 12 Pond 8P: Underground Chambers Retention for PDAs-1, 2, 3, & 5 - Chamber Wizard Field A Chamber Model = Lane Storm Keeper SK75(Lane StormKeeper) Effective Size= 44.7"W x 30.0"H => 6.61 sf x 7.081 = 46.8 cf Overall Size= 51.0"W x 30.0"H x 7.301 with 0.22' Overlap Cap Storage= +5.2 cf x 2 x 7 rows = 73.4 cf 51.0" Wide + 6.0" Spacing = 57.0" C-C Row Spacing 13 Chambers/Row x 7.08' Long +1.81' Cap Length x 2 = 95.59' Row Length +6.0" End Stone x 2 = 96.59' Base Length 7 Rows x 51.0" Wide + 6.0" Spacing x 6 + 12.0" Side Stone x 2 = 34.75' Base Width 6.0" Base + 30.0" Chamber Height + 6.0" Cover = 3.50' Field Height 91 Chambers x 46.8 cf + 5.2 cf Cap Volume x 2 x 7 Rows = 4,330.4 cf Chamber Storage 11,748.0 cf Field -4,330.4 cf Chambers = 7,417.6 cf Stone x 40.0% Voids = 2,967.0 cf Stone Storage Chamber Storage + Stone Storage = 7,297.4 cf= 0.168 of Overall Storage Efficiency = 62.1% Overall System Size = 96.59' x 34.75' x 3.50' 91 Chambers 435.1 cy Field 274.7 cy Stone 19 Coolidge Hill Rd - Watertown Proposed 2019 07 02 Type /// 24-hr 2 Year Rainfall=3.20" Prepared by {enter your company name here) Printed 8/13/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Page 13 Pond 8P: Underground Chambers Retention for PDAs-1, 2, 3, & 5 Hydrograph �IIIIIII1111111111111111 flw 1.98 cfs 0 D scarded 2�, I I I III I I I I I I I�r�fllo�nrl�4r�a�=b!8b� �� III III Oeak IEie"k 8i $tlo�algI6486 d IIIIIIII111 IIIIIII ' -I r- -r t I fi l -t t I -r t t -t I-t I rl .2 ,� 0.69 cfs IIIIIIIII � � � IIIII � � � IIIIII _ IIIIIIIIII IIII IIIIIII 0 /Z 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Proposed 2019 07 02 Type /// 24-hr 2 Year Rainfall=3.20" Prepared by {enter your company name here) Printed 8/13/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Page 14 Summary for Pond 10P: Round Leaching Structure 01 Inflow Area = 0.058 ac, 5.00% Impervious, Inflow Depth = 0.00" for 2 Year event Inflow = 0.00 cfs @ 0.00 hrs, Volume= 0.000 of Outflow = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af, Atten= 0%, Lag= 0.0 min Discarded = 0.00 cfs @ 0.00 hrs, Volume= 0.000 of Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Peak Elev= 36.00' @ 0.00 hrs Surf.Area= 28 sf Storage= 0 cf Plug-Flow detention time= (not calculated: initial storage exceeds outflow) Center-of-Mass det. time= (not calculated: no inflow) Volume Invert Avail.Storage Storage Description #1 36.00' 85 cf 6.00'D x 3.00'H Vertical Cone/Cylinder Device Routing Invert Outlet Devices #1 Discarded 36.00' 8.270 in/hr Exfiltration over Surface area Conductivity to Groundwater Elevation = 25.00' Discarded OutFlow Max=0.00 cfs @ 0.00 hrs HW=36.00' (Free Discharge) L1=Exfiltration (Passes 0.00 cfs of 0.01 cfs potential flow) Pond 10P: Round Leaching Structure 01 Hydrograph �I ■Inflow 1 ■Discarded III (Inflow Area=0.058 ac III l III Peak Elev=36.00' III Storage=0 cf I I I I I I I I I N V I I I I 3 0 LL 0.00 cfs 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Proposed 2019 07 02 Type /// 24-hr 2 Year Rainfall=3.20" Prepared by {enter your company name here) Printed 8/13/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 15 Summary for Link 20L: DPs-1, 2, 3, & 5: CB Rim near Arlington St. 0 Surcharge Elev.36.00 Inflow Area = 0.881 ac, 75.99% Impervious, Inflow Depth = 0.00" for 2 Year event Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 of Primary outflow = Inflow, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Link 20L: DPs-1, 2, 3, & 5: CB Rim near Arlington St. 0 Surcharge Elev.36.00 Hydrograph 1 � I ❑Primary Il41�l r A�eal=6.8611 ac IIIIIIIIIIIIIIIIIII IIIIIIIIIIIIIIIIIIII Illllllllllllllllll 3 IIIIIIIIIIIIII � � � I � 0 LL 0.00 cfs 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Proposed 2019 07 02 Type /// 24-hr 2 Year Rainfall=3.20" Prepared by {enter your company name here) Printed 8/13/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 16 Summary for Link 21 L: DP-4: Surcharge Zero Elev.42.25 Inflow Area = 0.058 ac, 5.00% Impervious, Inflow Depth = 0.00" for 2 Year event Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 of Primary outflow = Inflow, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Link 21 L: DP-4: Surcharge Zero Elev.42.25 Hydrograph ` 1 1■Primaryl i4�ea'=b.6�8 �C' O LL 0.00 cfs 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Proposed 2019 07 02-ype /// 24-hr 10 Year Rainfall=4.90" Prepared by {enter your company name here) Printed 8/13/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Page 17 Time span=0.00-30.00 hrs, dt=0.02 hrs, 1501 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment IS: PDA-1 4.9ksf Roof,Veh. Runoff Area=18,002 sf 82.67% Impervious Runoff Depth=3.99" Tc=5.0 min CN=92 Runoff=1.90 cfs 0.137 of Subcatchment2S: PDA-2 10ksf Roof Runoff Area=10,000 sf 100.00% Impervious Runoff Depth=4.66" Tc=5.0 min CN=98 Runoff=1.14 cfs 0.089 of Subcatchment3S: PDA-3 Pocket Park and Runoff Area=8,109 sf 31.64% Impervious Runoff Depth=0.81" Tc=5.0 min CN=53 Runoff=0.13 cfs 0.013 of Subcatchment4S: PDA-4 Landscape along Runoff Area=2,539 sf 5.00% Impervious Runoff Depth=0.07" Tc=5.0 min CN=35 Runoff=0.00 cfs 0.000 of Subcatchment SS: PDA-5 Arlington Street Runoff Area=2,249 sf 75.72% Impervious Runoff Depth=2.99" Tc=5.0 min CN=82 Runoff=0.19 cfs 0.013 of Pond 8P: Underground Chambers Retention Peak EIev=30.85' Storage=2,461 cf Inflow=3.35 cfs 0.252 of Outflow=0.73 cfs 0.252 of Pond 10P: Round Leaching Structure 01 Peak EIev=36.00' Storage=0 cf Inflow=0.00 cfs 0.000 of Outflow=0.00 cfs 0.000 of Link 20L: DPs-1,2, 3, & 5: CB Rim near Arlington St. 0 Surcharge Elev.36.00 Primary=0.00 cfs 0.000 of Link 21 L: DP-4: Surcharge Zero Elev.42.25 Primary=0.00 cfs 0.000 of Total Runoff Area = 0.939 ac Runoff Volume = 0.253 of Average Runoff Depth = 3.23" 28.41% Pervious = 0.267 ac 71.59% Impervious = 0.672 ac 19 Coolidge Hill Rd - Watertown Proposed 2019 07 02rype /// 24-hr 10 Year Rainfall=4.90" Prepared by {enter your company name here) Printed 8/13/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 18 Summary for Subcatchment 1 S: PDA-1 4.9ksf Roof, Veh. Paving, Slope,& Edge Landscape Runoff = 1.90 cfs @ 12.07 hrs, Volume= 0.137 af, Depth= 3.99" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Type III 24-hr 10 Year Rainfall=4.90" Area (sf) CN Description 8,035 98 Vehicular Pavement, HSG A 1,947 98 Pedestrian Pavement, HSG A 2,120 76 Steep Landscape, Good, HSG A 1,000 32 Landscape, Good, HSG A 4,900 98 Roof, HSG A 18,002 92 Weighted Average 3,120 17.33% Pervious Area 14,882 82.67% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, (assume minimum Tc) Subcatchment 1S: PDA-1 4.9ksf Roof, Veh. Paving, Slope,& Edge Landscape Hydrograph ❑Runoff 1.90 cfs I I I I ITll � II el II+ 24-hr Yp 11 d 1(6ai- Ida 1i 611=4.90" Rluihdffl Alyda#118,10021 sf u ffOlu 0. 7 ICI �Q I V I I ��� I1� Iaf JT ,� I t l t l - l R nQf �ep "T fi lTc=5.0 m i n - III ' IIIIIIII o ..... ....... .......�...,.... .... :.. .�.. . ... 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Proposed 2019 07 02rype /// 24-hr 10 Year Rainfall=4.90" Prepared by {enter your company name here) Printed 8/13/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 19 Summary for Subcatchment 2S: PDA-2 10ksf Roof Runoff = 1.14 cfs @ 12.07 hrs, Volume= 0.089 af, Depth= 4.66" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Type III 24-hr 10 Year Rainfall=4.90" Area (sf) CN Description 10,000 98 Roof, HSG A 10,000 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, (assume minimum Tc) Subcatchment 2S: PDA-2 10ksf Roof Hydrograph � ■Runoff 1.14 cfs 1 T��e II+ 24-h� - RluihW AlreaT1'0,100010 Ruggff�Violiume=0.0891 of Runoff Delpth=4.66'I 0 LL Tc=5.0 m i n IIIIIIIIII I ' IIIIIIIIII 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Proposed 2019 07 02rype /// 24-hr 10 Year Rainfall=4.90" Prepared by {enter your company name here) Printed 8/13/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 20 Summary for Subcatchment 3S: PDA-3 Pocket Park and Abutter Runoff = 0.13 cfs @ 12.10 hrs, Volume= 0.013 af, Depth= 0.81" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Type III 24-hr 10 Year Rainfall=4.90" Area (sf) CN Description 1,172 98 Pedestrian Pavement, HSG A 1,394 98 Roof, HSG A 5,543 32 Landscape, Good, HSG A 8,109 53 Weighted Average 5,543 68.36% Pervious Area 2,566 31.64% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, (assume minimum Tc) Subcatchment 3S: PDA-3 Pocket Park and Abutter Hydrograph i O Runoff 0.14' 0.13 cfs 0.13-�'/ Ty e I I i 2+41h-� 0.12�-/ 0.11 1 + H H ft nbfff-Arley-8,11991 s# 0.1� -Tc=5.0-m M 0.053 0.04� fifi � �i firth � firt 0.03�-/ � I 0.02-�'/ o- /../....�/../....� 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Proposed 2019 07 02rype /// 24-hr 10 Year Rainfall=4.90" Prepared by {enter your company name here) Printed 8/13/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 21 Summary for Subcatchment 4S: PDA-4 Landscape along CHR Runoff = 0.00 cfs @ 15.29 hrs, Volume= 0.000 af, Depth= 0.07" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Type III 24-hr 10 Year Rainfall=4.90" Area (sf) CN Description 127 98 Pedestrian Pavement, HSG A 2,412 32 Landscape, Good, HSG A 2,539 35 Weighted Average 2,412 95.00% Pervious Area 127 5.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, (assume minimum Tc) Subcatchment 4S: PDA-4 Landscape along CHR Hydrograph � � � IIIIII � IIIIIIIII ■Runoff 0.001-�'z � � 0.00 cfs 0.001 i�ple�l24-h1� 0.000-�/ i"earl Rainfalll=4�90" 1 T 1 -4 1--] 1 T 0.000 -fthoff A1reA=�2�5 3"f- --1 1 T 0.000-�/ 11IRZY90ff Yglylp"- I T TIT TI T 3 0.000�1� � � -�•P I� LI T L L1 T 0.00031/ 0.000-�/ 0� fi I T o� III 0 ., 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Proposed 2019 07 02rype /// 24-hr 10 Year Rainfall=4.90" Prepared by {enter your company name here) Printed 8/13/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 22 Summary for Subcatchment 5S: PDA-5 Arlington Street Public Pedestrian Bike Area Runoff = 0.19 cfs @ 12.07 hrs, Volume= 0.013 af, Depth= 2.99" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Type III 24-hr 10 Year Rainfall=4.90" Area (sf) CN Description 1,703 98 Pedestrian Pavement, HSG A 546 32 Landscape, Good, HSG A 2,249 82 Weighted Average 546 24.28% Pervious Area 1,703 75.72% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, (assume minimum Tc) Subcatchment 5S: PDA-5 Arlington Street Public Pedestrian Bike Area Hydrograph — � � I � i i � � �I � � i� � � ❑Runoff 0.2 0.19cfs 0 19' P [--I � I -4 1�� �i - 0.18�-0.17 1 - - - I 0.15 -I � I + 1 1 �I 1� �1 ftnbff-Attu 2,1491 sf 0.13=/— 0.12� t 1 t I t-I I�N�fftV1�rp�=G•pT31af °0.1--I - 1 - l - 1 1 -1 rtl_ - �-' FL 0.09- -Tc-5.Vm i n 0.08�zL Z I I 1 1 LI L L-] C Z 1 1 1-1 ❑ 0.07 0.06 /�1 0.05= I 0.04�� � I - -4 1 4 1-4 II � 1 14 0.03- 0.02 /� -�- I + 14 H 14 1-�i Hi �1- 1 + 14 0.01-- / i 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Proposed 2019 07 02-ype /// 24-hr 10 Year Rainfall=4.90" Prepared by {enter your company name here) Printed 8/13/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Page 23 Summary for Pond 8P: Underground Chambers Retention for PDAs-1, 2, 3, & 5 Inflow Area = 0.881 ac, 75.99% Impervious, Inflow Depth = 3.44" for 10 Year event Inflow = 3.35 cfs @ 12.07 hrs, Volume= 0.252 of Outflow = 0.73 cfs @ 12.48 hrs, Volume= 0.252 af, Atten= 78%, Lag= 24.4 min Discarded = 0.73 cfs @ 12.48 hrs, Volume= 0.252 of Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Peak Elev= 30.85' @ 12.48 hrs Surf.Area= 3,357 sf Storage= 2,461 cf Plug-Flow detention time= 18.0 min calculated for 0.252 of(100% of inflow) Center-of-Mass det. time= 18.0 min ( 795.8 - 777.8 ) Volume Invert Avail.Storage Storaqe Description #1A 29.70' 2,967 cf 34.75'W x 96.59'L x 3.50'H Field A 11,748 cf Overall -4,330 cf Embedded = 7,418 cf x 40.0% Voids #2A 30.20' 4,330 cf Lane Storm Keeper SK75 x 91 Inside#1 Effective Size= 44.7"W x 30.0"H => 6.61 sf x 7.081 = 46.8 cf Overall Size= 51.0"W x 30.0"H x 7.30'L with 0.22' Overlap 91 Chambers in 7 Rows Cap Storaqe= +5.2 cf x 2 x 7 rows = 73.4 cf 7,297 cf Total Available Storage Storage Group A created with Chamber Wizard Device Routinq Invert Outlet Devices #1 Discarded 29.70' 8.270 in/hr Exfiltration over Horizontal area Conductivity to Groundwater Elevation = 21.00' Discarded OutFlow Max=0.73 cfs @ 12.48 hrs HW=30.85' (Free Discharge) L1=Exfiltration ( Controls 0.73 cfs) 19 Coolidge Hill Rd - Watertown Proposed 2019 07 02rype /// 24-hr 10 Year Rainfall=4.90" Prepared by {enter your company name here) Printed 8/13/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 24 Pond 8P: Underground Chambers Retention for PDAs-1, 2, 3, & 5 - Chamber Wizard Field A Chamber Model = Lane Storm Keeper SK75(Lane StormKeeper) Effective Size= 44.7"W x 30.0"H => 6.61 sf x 7.081 = 46.8 cf Overall Size= 51.0"W x 30.0"H x 7.301 with 0.22' Overlap Cap Storage= +5.2 cf x 2 x 7 rows = 73.4 cf 51.0" Wide + 6.0" Spacing = 57.0" C-C Row Spacing 13 Chambers/Row x 7.08' Long +1.81' Cap Length x 2 = 95.59' Row Length +6.0" End Stone x 2 = 96.59' Base Length 7 Rows x 51.0" Wide + 6.0" Spacing x 6 + 12.0" Side Stone x 2 = 34.75' Base Width 6.0" Base + 30.0" Chamber Height + 6.0" Cover = 3.50' Field Height 91 Chambers x 46.8 cf + 5.2 cf Cap Volume x 2 x 7 Rows = 4,330.4 cf Chamber Storage 11,748.0 cf Field -4,330.4 cf Chambers = 7,417.6 cf Stone x 40.0% Voids = 2,967.0 cf Stone Storage Chamber Storage + Stone Storage = 7,297.4 cf= 0.168 of Overall Storage Efficiency = 62.1% Overall System Size = 96.59' x 34.75' x 3.50' 91 Chambers 435.1 cy Field 274.7 cy Stone 19 Coolidge Hill Rd - Watertown Proposed 2019 07 02rype /// 24-hr 10 Year Rainfall=4.90" Prepared by {enter your company name here) Printed 8/13/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Page 25 Pond 8P: Underground Chambers Retention for PDAs-1, 2, 3, & 5 Hydrograph / ❑Inflow 3.35 cfs — 0 Discarded _ IIr�fllo�nrlAr�a�-b.8�'� _ 3� III III III Oeak Ibe"k.815� � III III Storage=4,461 d " 2 IIIIIIIIIII 3 - 0 LL I IIIII IIIIIIIIIIII - IIIIIIII Illlll IIIIII � IIIIIII o ... ...�.. .... ....�:../..../....�.. 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Proposed 2019 07 02-ype /// 24-hr 10 Year Rainfall=4.90" Prepared by {enter your company name here) Printed 8/13/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Page 26 Summary for Pond 10P: Round Leaching Structure 01 Inflow Area = 0.058 ac, 5.00% Impervious, Inflow Depth = 0.07" for 10 Year event Inflow = 0.00 cfs @ 15.29 hrs, Volume= 0.000 of Outflow = 0.00 cfs @ 15.32 hrs, Volume= 0.000 af, Atten= 0%, Lag= 2.1 min Discarded = 0.00 cfs @ 15.32 hrs, Volume= 0.000 of Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Peak Elev= 36.00' @ 15.32 hrs Surf.Area= 28 sf Storage= 0 cf Plug-Flow detention time= 2.6 min calculated for 0.000 of(100% of inflow) Center-of-Mass det. time= 2.6 min ( 1,103.7 - 1,101.1 ) Volume Invert Avail.Storage Storage Description #1 36.00' 85 cf 6.00'D x 3.00'H Vertical Cone/Cylinder Device Routing Invert Outlet Devices #1 Discarded 36.00' 8.270 in/hr Exfiltration over Surface area Conductivity to Groundwater Elevation = 25.00' Discarded OutFlow Max=0.01 cfs @ 15.32 hrs HW=36.00' (Free Discharge) L1=Exfiltration ( Controls 0.01 cfs) Pond 10P: Round Leaching Structure 01 Hydrograph _ ■Inflow 0.00 CfS 11 11 LI LI L I L I I M Discarded 001 Inflow Area=0.0., 0.001= ' Peak Elev=36.00' E I-] H HI -I 4- 1 T 0 .00 03-// Storage=0 cf TI TI T I T I T 0.000�/ 0.000�z I I I N " 3 0.000�z �_1 �_1 T 1 T I 1 T 1 LL 0.000-�/ —1 HH t I t I t I I T I t °°°�'/ T TI T T I T I T T I T I T 0.0003 0�z 01 o /.. 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Proposed 2019 07 02rype /// 24-hr 10 Year Rainfall=4.90" Prepared by {enter your company name here) Printed 8/13/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 27 Summary for Link 20L: DPs-1, 2, 3, & 5: CB Rim near Arlington St. 0 Surcharge Elev.36.00 Inflow Area = 0.881 ac, 75.99% Impervious, Inflow Depth = 0.00" for 10 Year event Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 of Primary outflow = Inflow, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Link 20L: DPs-1, 2, 3, & 5: CB Rim near Arlington St. 0 Surcharge Elev.36.00 Hydrograph 1 � I ❑Primary Il41�l r A�eal=6.8611 ac IIIIIIIIIIIIIIIIIII IIIIIIIIIIIIIIIIIIII Illllllllllllllllll 3 IIIIIIIIIIIIII � � � I � 0 LL 0.00 cfs 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Proposed 2019 07 02rype /// 24-hr 10 Year Rainfall=4.90" Prepared by {enter your company name here) Printed 8/13/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 28 Summary for Link 21 L: DP-4: Surcharge Zero Elev.42.25 Inflow Area = 0.058 ac, 5.00% Impervious, Inflow Depth = 0.00" for 10 Year event Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 of Primary outflow = Inflow, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Link 21 L: DP-4: Surcharge Zero Elev.42.25 Hydrograph ` 1 1■Primaryl i4�ea'=b.6�8 �C' O LL 0.00 cfs 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Proposed 2019 07 02-ype /// 24-hr 25 Year Rainfall=6.20" Prepared by {enter your company name here) Printed 8/13/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Page 29 Time span=0.00-30.00 hrs, dt=0.02 hrs, 1501 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment IS: PDA-1 4.9ksf Roof,Veh. Runoff Area=18,002 sf 82.67% Impervious Runoff Depth=5.27" Tc=5.0 min CN=92 Runoff=2.46 cfs 0.181 of Subcatchment2S: PDA-2 10ksf Roof Runoff Area=10,000 sf 100.00% Impervious Runoff Depth=5.96" Tc=5.0 min CN=98 Runoff=1.44 cfs 0.114 of Subcatchment3S: PDA-3 Pocket Park and Runoff Area=8,109 sf 31.64% Impervious Runoff Depth=1.47" Tc=5.0 min CN=53 Runoff=0.29 cfs 0.023 of Subcatchment4S: PDA-4 Landscape along Runoff Area=2,539 sf 5.00% Impervious Runoff Depth=0.29" Tc=5.0 min CN=35 Runoff=0.00 cfs 0.001 of Subcatchment SS: PDA-5 Arlington Street Runoff Area=2,249 sf 75.72% Impervious Runoff Depth=4.17" Tc=5.0 min CN=82 Runoff=0.26 cfs 0.018 of Pond 8P: Underground Chambers Retention Peak Elev=31.39' Storage=3,880 cf Inflow=4.45 cfs 0.336 of Outflow=0.77 cfs 0.336 of Pond 10P: Round Leaching Structure 01 Peak Elev=36.02' Storage=1 cf Inflow=0.00 cfs 0.001 of Outflow=0.00 cfs 0.001 of Link 20L: DPs-1,2, 3, & 5: CB Rim near Arlington St. 0 Surcharge Elev.36.00 Primary=0.00 cfs 0.000 of Link 21 L: DP-4: Surcharge Zero Elev.42.25 Primary=0.00 cfs 0.000 of Total Runoff Area = 0.939 ac Runoff Volume = 0.338 of Average Runoff Depth = 4.32" 28.41% Pervious = 0.267 ac 71.59% Impervious = 0.672 ac 19 Coolidge Hill Rd - Watertown Proposed 2019 07 02rype /// 24-hr 25 Year Rainfall=6.20" Prepared by {enter your company name here) Printed 8/13/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 30 Summary for Subcatchment 1 S: PDA-1 4.9ksf Roof, Veh. Paving, Slope,& Edge Landscape Runoff = 2.46 cfs @ 12.07 hrs, Volume= 0.181 af, Depth= 5.27" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Type III 24-hr 25 Year Rainfall=6.20" Area (sf) CN Description 8,035 98 Vehicular Pavement, HSG A 1,947 98 Pedestrian Pavement, HSG A 2,120 76 Steep Landscape, Good, HSG A 1,000 32 Landscape, Good, HSG A 4,900 98 Roof, HSG A 18,002 92 Weighted Average 3,120 17.33% Pervious Area 14,882 82.67% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, (assume minimum Tc) Subcatchment 1S: PDA-1 4.9ksf Roof, Veh. Paving, Slope,& Edge Landscape Hydrograph I I I i I I I ❑Runoff I 2.46 cfs I Ty Y�a II+ 24 �-hrl 12� 1Y6aII- OZa 1 611�=6.20" 2—/ 1 1 1 1 ' RluihdfflAlyda#118,10021sf Ruggffl Vlollugnp70.11 q11 of 3 1 1 1 1 1 1 Rulnpf l Pep�h7�.�T'1 LL Tc=5.0 m i n 1 1tIt 1t1t � =� - I1I1 ' lllllll 0 � ............................ ...�.... ... .... :...�.... .... .... .... .... .... .... .... ....,....,....,....,....,....,....,....,....,...., 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Proposed 2019 07 02rype /// 24-hr 25 Year Rainfall=6.20" Prepared by {enter your company name here) Printed 8/13/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 31 Summary for Subcatchment 2S: PDA-2 10ksf Roof Runoff = 1.44 cfs @ 12.07 hrs, Volume= 0.114 af, Depth= 5.96" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Type III 24-hr 25 Year Rainfall=6.20" Area (sf) CN Description 10,000 98 Roof, HSG A 10,000 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, (assume minimum Tc) Subcatchment 2S: PDA-2 10ksf Roof Hydrograph � ■Runoff 1.44 cfs T��e II+ 241h� I 12� 1f�ai- F�a�ir�fa�ll�( .210'I' Rluihdffl Alyda01i0,10001 sf Ruggff�Violiume=0.1141 of Runoff Delpth=5.96'I 0 LL Tc=5.0 m i n IIIIIIIIII I ' IIIIIIIIII o ..�./../....i.. ...�..., ..�, ..�................ 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Proposed 2019 07 02rype /// 24-hr 25 Year Rainfall=6.20" Prepared by {enter your company name here) Printed 8/13/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 32 Summary for Subcatchment 3S: PDA-3 Pocket Park and Abutter Runoff = 0.29 cfs @ 12.09 hrs, Volume= 0.023 af, Depth= 1.47" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Type III 24-hr 25 Year Rainfall=6.20" Area (sf) CN Description 1,172 98 Pedestrian Pavement, HSG A 1,394 98 Roof, HSG A 5,543 32 Landscape, Good, HSG A 8,109 53 Weighted Average 5,543 68.36% Pervious Area 2,566 31.64% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, (assume minimum Tc) Subcatchment 3S: PDA-3 Pocket Park and Abutter Hydrograph 0.32 + t- I + I Runoff o°s� —i 0.29 cfs �y�e� i � h 1' 0.26�-' 0.24-�'/ 0 22� fi fi 1-1 H �nbff-Arte�=1�,1091 sf c 0.16� - LL 0.14�-/ -Tc=-5J.0min 0.12 ItItIrt �' fiItI-tr-It6fi 01 I �- 1 1 - 1 1--� 1 41 1 14 0.08->- / _ 0.06 0.04->- / 0.02/ Ifilfil � l L I � 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Proposed 2019 07 02rype /// 24-hr 25 Year Rainfall=6.20" Prepared by {enter your company name here) Printed 8/13/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 33 Summary for Subcatchment 4S: PDA-4 Landscape along CHR Runoff = 0.00 cfs @ 12.42 hrs, Volume= 0.001 af, Depth= 0.29" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Type III 24-hr 25 Year Rainfall=6.20" Area (sf) CN Description 127 98 Pedestrian Pavement, HSG A 2,412 32 Landscape, Good, HSG A 2,539 35 Weighted Average 2,412 95.00% Pervious Area 127 5.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, (assume minimum Tc) Subcatchment 4S: PDA-4 Landscape along CHR Hydrograph 0.005-�//— i I I :I I-1 �I L El E :E Runoff 0.005� — 0.00 cfs 0 004 I + 14 1 � 1 1 �y4 I�I 2 h 0.004 0.004 � I C�� ain�fal6�20 0.004 0.003 -1 � 14 1-I H 14 RUrl6ff Ar"="3 F& 0.003 — — — — — — — — — N 0:003 -I I� CIfQ = 1 3 0002 = + 4 �: �z 1 1-1 7I94-0 0.002� � 1 C�J.O—Mlrlr 0:002 -1 I� CI CI t IIt �3 0.001 0.001 — — — 0.001 0,001- 0.001/ — 0.000/ I 4- 0.000 a i 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Proposed 2019 07 02rype /// 24-hr 25 Year Rainfall=6.20" Prepared by {enter your company name here) Printed 8/13/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 34 Summary for Subcatchment 5S: PDA-5 Arlington Street Public Pedestrian Bike Area Runoff = 0.26 cfs @ 12.07 hrs, Volume= 0.018 af, Depth= 4.17" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Type III 24-hr 25 Year Rainfall=6.20" Area (sf) CN Description 1,703 98 Pedestrian Pavement, HSG A 546 32 Landscape, Good, HSG A 2,249 82 Weighted Average 546 24.28% Pervious Area 1,703 75.72% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, (assume minimum Tc) Subcatchment 5S: PDA-5 Arlington Street Public Pedestrian Bike Area Hydrograph 1 -T- 14 -i +- I --F , 1 t— i ❑Runoff 0.28 0.26 cfs 0.26�= T 1 T 17 F-1 T I T 17T�e T2-4 h 0.24: I - 1 T 1 -4 �-1 0.22-�'/ 2 `� a� ahl�fa�tt��2cf'� 0.2 _ T 1 T I T T I -T ftnof1f-Ane�T2,149 0.18'— T RN9-9f�VP����-p-81 at 0 0.14=/T T T TI T T �IpT �l?T FL 0.12� 1 c . 1 T -4 1 - T 11-4 �I �-6k=18� 0.13'/� I am0 ,/TI T I T 17 1 F 1 T T 1 T TI 7- 1 T FT 0.04_ 0.02�-Z T T- 1 T 17 T T ITT T o 1.. .1...... 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Proposed 2019 07 02-ype /// 24-hr 25 Year Rainfall=6.20" Prepared by {enter your company name here) Printed 8/13/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Page 35 Summary for Pond 8P: Underground Chambers Retention for PDAs-1, 2, 3, & 5 Inflow Area = 0.881 ac, 75.99% Impervious, Inflow Depth = 4.58" for 25 Year event Inflow = 4.45 cfs @ 12.07 hrs, Volume= 0.336 of Outflow = 0.77 cfs @ 12.53 hrs, Volume= 0.336 af, Atten= 83%, Lag= 27.3 min Discarded = 0.77 cfs @ 12.53 hrs, Volume= 0.336 of Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Peak Elev= 31.39' @ 12.53 hrs Surf.Area= 3,357 sf Storage= 3,880 cf Plug-Flow detention time= 29.9 min calculated for 0.336 of(100% of inflow) Center-of-Mass det. time= 29.9 min ( 803.3 - 773.4 ) Volume Invert Avail.Storage Storaqe Description #1A 29.70' 2,967 cf 34.75'W x 96.59'L x 3.50'H Field A 11,748 cf Overall -4,330 cf Embedded = 7,418 cf x 40.0% Voids #2A 30.20' 4,330 cf Lane Storm Keeper SK75 x 91 Inside#1 Effective Size= 44.7"W x 30.0"H => 6.61 sf x 7.081 = 46.8 cf Overall Size= 51.0"W x 30.0"H x 7.30'L with 0.22' Overlap 91 Chambers in 7 Rows Cap Storaqe= +5.2 cf x 2 x 7 rows = 73.4 cf 7,297 cf Total Available Storage Storage Group A created with Chamber Wizard Device Routinq Invert Outlet Devices #1 Discarded 29.70' 8.270 in/hr Exfiltration over Horizontal area Conductivity to Groundwater Elevation = 21.00' Discarded OutFlow Max=0.77 cfs @ 12.53 hrs HW=31.39' (Free Discharge) L1=Exfiltration ( Controls 0.77 cfs) 19 Coolidge Hill Rd - Watertown Proposed 2019 07 02rype /// 24-hr 25 Year Rainfall=6.20" Prepared by {enter your company name here) Printed 8/13/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 36 Pond 8P: Underground Chambers Retention for PDAs-1, 2, 3, & 5 - Chamber Wizard Field A Chamber Model = Lane Storm Keeper SK75(Lane StormKeeper) Effective Size= 44.7"W x 30.0"H => 6.61 sf x 7.081 = 46.8 cf Overall Size= 51.0"W x 30.0"H x 7.301 with 0.22' Overlap Cap Storage= +5.2 cf x 2 x 7 rows = 73.4 cf 51.0" Wide + 6.0" Spacing = 57.0" C-C Row Spacing 13 Chambers/Row x 7.08' Long +1.81' Cap Length x 2 = 95.59' Row Length +6.0" End Stone x 2 = 96.59' Base Length 7 Rows x 51.0" Wide + 6.0" Spacing x 6 + 12.0" Side Stone x 2 = 34.75' Base Width 6.0" Base + 30.0" Chamber Height + 6.0" Cover = 3.50' Field Height 91 Chambers x 46.8 cf + 5.2 cf Cap Volume x 2 x 7 Rows = 4,330.4 cf Chamber Storage 11,748.0 cf Field -4,330.4 cf Chambers = 7,417.6 cf Stone x 40.0% Voids = 2,967.0 cf Stone Storage Chamber Storage + Stone Storage = 7,297.4 cf= 0.168 of Overall Storage Efficiency = 62.1% Overall System Size = 96.59' x 34.75' x 3.50' 91 Chambers 435.1 cy Field 274.7 cy Stone 19 Coolidge Hill Rd - Watertown Proposed 2019 07 02rype /// 24-hr 25 Year Rainfall=6.20" Prepared by {enter your company name here) Printed 8/13/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Page 37 Pond 8P: Underground Chambers Retention for PDAs-1, 2, 3, & 5 Hydrograph / I I I I 1 ❑Inflow 4.45 cfs — 0 Discarded Ir�flo�nr �4r�a�—b.8�'� — 4� Oeak IEie"� 11 319� 3� IIIIIIIIII IIIIIIIIIIIIIIIII - IIIIII � � IIIIIIIIIIIIIII 3 - � 0 " 2� IIIIIIIIII IIIIIIIIIIIIIIII LI L I I I A L I IA L L 1� III 0.77 cfs I I I o .. .... ... ... ....r..�:.......(.::..(....�.. ,. 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Proposed 2019 07 02-ype /// 24-hr 25 Year Rainfall=6.20" Prepared by {enter your company name here) Printed 8/13/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Page 38 Summary for Pond 10P: Round Leaching Structure 01 Inflow Area = 0.058 ac, 5.00% Impervious, Inflow Depth = 0.29" for 25 Year event Inflow = 0.00 cfs @ 12.42 hrs, Volume= 0.001 of Outflow = 0.00 cfs @ 12.47 hrs, Volume= 0.001 af, Atten= 4%, Lag= 2.7 min Discarded = 0.00 cfs @ 12.47 hrs, Volume= 0.001 of Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Peak Elev= 36.02' @ 12.47 hrs Surf.Area= 28 sf Storage= 1 cf Plug-Flow detention time= 2.6 min calculated for 0.001 of(100% of inflow) Center-of-Mass det. time= 2.6 min ( 997.6 - 995.0 ) Volume Invert Avail.Storage Storaqe Description #1 36.00' 85 cf 6.00'D x 3.00'H Vertical Cone/Cylinder Device Routinq Invert Outlet Devices #1 Discarded 36.00' 8.270 in/hr Exfiltration over Surface area Conductivity to Groundwater Elevation = 25.00' Discarded OutFlow Max=0.01 cfs @ 12.47 hrs HW=36.02' (Free Discharge) L1=Exfiltration ( Controls 0.01 cfs) Pond 10P: Round Leaching Structure 01 Hydrograph M Inflow 0.0052 0.00 cfs r ■Discarded o.00a11/ 0.00 cfs 1 1 -f�I'1V1F/4'� =U. � aC 0.004_✓ - r- - - - V - 0.004� ,-I -I -I l fi l rt Irt I� I� 1S o e� �C 0.003� -� 0.003� �- 0.003�1/ �I H �1 1_ 1 + 1 14 I-A 1-1 H H t-I -k1 N 0.003 ,- - - - - - - - - - 0.003� r- 0.002 1� 1::] CI Li �I L I I 0 0.002 LL 0.002: + + H H + 0.002 0.002 0.001� ,- -1 �I J- I � I T �1 �1 L_I J_ I � 0.001 - 0.001 0.001 t-I tI tI I I tI t 0.001= 0.000 0.000- 0- . 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Proposed 2019 07 02rype /// 24-hr 25 Year Rainfall=6.20" Prepared by {enter your company name here) Printed 8/13/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 39 Summary for Link 20L: DPs-1, 2, 3, & 5: CB Rim near Arlington St. 0 Surcharge Elev.36.00 Inflow Area = 0.881 ac, 75.99% Impervious, Inflow Depth = 0.00" for 25 Year event Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 of Primary outflow = Inflow, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Link 20L: DPs-1, 2, 3, & 5: CB Rim near Arlington St. 0 Surcharge Elev.36.00 Hydrograph 1 � I ❑Primary Il41�l r A�eal=6.8611 ac IIIIIIIIIIIIIIIIIII IIIIIIIIIIIIIIIIIIII Illllllllllllllllll 3 IIIIIIIIIIIIII � � � I � 0 LL 0.00 cfs 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Proposed 2019 07 02rype /// 24-hr 25 Year Rainfall=6.20" Prepared by {enter your company name here) Printed 8/13/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 40 Summary for Link 21 L: DP-4: Surcharge Zero Elev.42.25 Inflow Area = 0.058 ac, 5.00% Impervious, Inflow Depth = 0.00" for 25 Year event Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 of Primary outflow = Inflow, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Link 21 L: DP-4: Surcharge Zero Elev.42.25 Hydrograph ` 1 1■Primaryl i4�ea'=b.6�8 �C' O LL 0.00 cfs 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Proposed 2019 07 (Type /// 24-hr 100 Year Rainfall=8.90" Prepared by {enter your company name here) Printed 8/13/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Page 41 Time span=0.00-30.00 hrs, dt=0.02 hrs, 1501 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment IS: PDA-1 4.9ksf Roof,Veh. Runoff Area=18,002 sf 82.67% Impervious Runoff Depth=7.94" Tc=5.0 min CN=92 Runoff=3.63 cfs 0.273 of Subcatchment2S: PDA-2 10ksf Roof Runoff Area=10,000 sf 100.00% Impervious Runoff Depth=8.66" Tc=5.0 min CN=98 Runoff=2.07 cfs 0.166 of Subcatchment3S: PDA-3 Pocket Park and Runoff Area=8,109 sf 31.64% Impervious Runoff Depth=3.18" Tc=5.0 min CN=53 Runoff=0.69 cfs 0.049 of Subcatchment4S: PDA-4 Landscape along Runoff Area=2,539 sf 5.00% Impervious Runoff Depth=1.13" Tc=5.0 min CN=35 Runoff=0.05 cfs 0.005 of Subcatchment SS: PDA-5 Arlington Street Runoff Area=2,249 sf 75.72% Impervious Runoff Depth=6.72" Tc=5.0 min CN=82 Runoff=0.41 cfs 0.029 of Pond 8P: Underground Chambers Retention Peak EIev=33.02' Storage=7,053 cf Inflow=6.79 cfs 0.517 of Outflow=0.89 cfs 0.517 of Pond 10P: Round Leaching Structure 01 Peak EIev=38.52' Storage=71 cf Inflow=0.05 cfs 0.005 of Outflow=0.01 cfs 0.005 of Link 20L: DPs-1,2, 3, & 5: CB Rim near Arlington St. 0 Surcharge Elev.36.00 Primary=0.00 cfs 0.000 of Link 21 L: DP-4: Surcharge Zero Elev.42.25 Primary=0.00 cfs 0.000 of Total Runoff Area = 0.939 ac Runoff Volume = 0.523 of Average Runoff Depth = 6.68" 28.41% Pervious = 0.267 ac 71.59% Impervious = 0.672 ac 19 Coolidge Hill Rd - Watertown Proposed 2019 07 (Type /// 24-hr 100 Year Rainfall=8.90" Prepared by {enter your company name here) Printed 8/13/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 42 Summary for Subcatchment 1 S: PDA-1 4.9ksf Roof, Veh. Paving, Slope,& Edge Landscape Runoff = 3.63 cfs @ 12.07 hrs, Volume= 0.273 af, Depth= 7.94" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Type III 24-hr 100 Year Rainfall=8.90" Area (sf) CN Description 8,035 98 Vehicular Pavement, HSG A 1,947 98 Pedestrian Pavement, HSG A 2,120 76 Steep Landscape, Good, HSG A 1,000 32 Landscape, Good, HSG A 4,900 98 Roof, HSG A 18,002 92 Weighted Average 3,120 17.33% Pervious Area 14,882 82.67% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, (assume minimum Tc) Subcatchment 1S: PDA-1 4.9ksf Roof, Veh. Paving, Slope,& Edge Landscape + Hydrograph + 4 / T —T ❑Runoff I I I I I I I I I 3.63 cfs I I I I I �� I l T e II+ 24-�hr i 0d $(�air-k"f�11�=4.90" 3� I RU hdffl Alyda#118,10021 sf RUggfflVOIIIU np70.12731of 3 2—/ 1 1 1 1 1 1 - I RI i"'r"flf ��h77.�' Tc=5.0 m i n 1 0 .......................... ....(...�.... ... .... :.../.... .... .... .... .... .... ....,.... ....,....,....,....,....,....,....,....,....,...., 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Proposed 2019 07 (Type /// 24-hr 100 Year Rainfall=8.90" Prepared by {enter your company name here) Printed 8/13/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 43 Summary for Subcatchment 2S: PDA-2 10ksf Roof Runoff = 2.07 cfs @ 12.07 hrs, Volume= 0.166 af, Depth= 8.66" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Type III 24-hr 100 Year Rainfall=8.90" Area (sf) CN Description 10,000 98 Roof, HSG A 10,000 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, (assume minimum Tc) Subcatchment 2S: PDA-2 10ksf Roof Hydrograph � ■Runoff 2.07 cfs - 2-% T I iOb 1f�aIIr �tair�fa�11�8�.910'1' RlutiW AlreaT110,100010 Ruggff�Violiume=0.1661 of Runoff Depth=8.66" 3 _ �I �c=5.0min _ IIIIIIIIII IIIIIIIIIIIIIIIII 0 - 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Proposed 2019 07 (Type /// 24-hr 100 Year Rainfall=8.90" Prepared by {enter your company name here) Printed 8/13/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 44 Summary for Subcatchment 3S: PDA-3 Pocket Park and Abutter Runoff = 0.69 cfs @ 12.08 hrs, Volume= 0.049 af, Depth= 3.18" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Type III 24-hr 100 Year Rainfall=8.90" Area (sf) CN Description 1,172 98 Pedestrian Pavement, HSG A 1,394 98 Roof, HSG A 5,543 32 Landscape, Good, HSG A 8,109 53 Weighted Average 5,543 68.36% Pervious Area 2,566 31.64% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, (assume minimum Tc) Subcatchment 3S: PDA-3 Pocket Park and Abutter Hydrograph 0.75 �i A I L 14 L 14 A k I � I L 1-44� � p Runoff 0.7=-'I I I 0 69 cfs IT��elfli I4 I� 0.65�I � I L I - 0.6 OT.``�Me�,a -l �a,,iAr,��fajTl A���9�0'� 0.55� L I L L L I L L I RO nb 111_�''�'ei�Ja 1 09I Sf 0.5-�'/ ff Vo l u N 0.45��1 fi l l II rt l y •plaf 3 0.4-i'/ � eIp�r��l� i-°° 0.35--�/ Tc-5.0-min 0.25='_I T-I 0.2 _ 0.15-�-/_ LILL L LI L LIL L LILIL 0.1� + 0.05� fi I L 0 .� :..(.:. ,:...�:..,:..,....(:...,. 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Proposed 2019 07 (Type /// 24-hr 100 Year Rainfall=8.90" Prepared by {enter your company name here) Printed 8/13/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 45 Summary for Subcatchment 4S: PDA-4 Landscape along CHR Runoff = 0.05 cfs @ 12.11 hrs, Volume= 0.005 af, Depth= 1.13" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Type III 24-hr 100 Year Rainfall=8.90" Area (sf) CN Description 127 98 Pedestrian Pavement, HSG A 2,412 32 Landscape, Good, HSG A 2,539 35 Weighted Average 2,412 95.00% Pervious Area 127 5.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, (assume minimum Tc) Subcatchment 4S: PDA-4 Landscape along CHR Hydrograph 0.05 — - - i I - - - - — - - - - Runoff 0.04 -1 - - I - 1- 0.05 cfs 0.046 I- -l y e I -I 0.044 0.042 -I - - - I- -I - I � I*0(�*fi� �Iip�s fl g= I&- 0.04 0.038 0.036 - 1 - 1- - 1 - --1ftnb#f� 6► i=", 391 sf 0.034 — — 0:026 -1 - t � 1- -I - - I � �r �I��f ,13fi 0 0.024 — c- =:10-min_ LL 0.022 — 0.02 -I -1 - I - I- - - I -� I - 1 0.018 — 0.016 I - - CI - - I - - - - 0.014 0.012 — 0.008'— 0.006- — - 0.004� 7 1- - 0.002- 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Proposed 2019 07 (Type /// 24-hr 100 Year Rainfall=8.90" Prepared by {enter your company name here) Printed 8/13/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 46 Summary for Subcatchment 5S: PDA-5 Arlington Street Public Pedestrian Bike Area Runoff = 0.41 cfs @ 12.07 hrs, Volume= 0.029 af, Depth= 6.72" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Type III 24-hr 100 Year Rainfall=8.90" Area (sf) CN Description 1,703 98 Pedestrian Pavement, HSG A 546 32 Landscape, Good, HSG A 2,249 82 Weighted Average 546 24.28% Pervious Area 1,703 75.72% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, (assume minimum Tc) Subcatchment 5S: PDA-5 Arlington Street Public Pedestrian Bike Area Hydrograp Ih 1 — � I � i fi � —t 1 � � � � i � ❑Runoff 0.44 0.42_ — - —I � I + I � I 0.41 c s I� �I � I � I� � 0.4- — — T�e� 2+41h-� 0.38 - 7 L:I -L L-1 Ca106�`�ea� a fa�I1� 90' 0.34 0.32� � I � I -4 �1 4 R0 ra bflf Attu-I2,1491 Sf 0.3- 0:20% I� I1� fPlF� 10.p�91 af 0.2LZ � I I a E1 :I El CI ��r �p 0 +=71� � 0.22_ 0.18-- 1 � - t- - 1-� �I 1- 4 — IL.k=16 0.16�— - 0.14 �I fi1 fi l � l l + I l- -1 - - l- -1 - 1 - - 0.1 �1 � 1 11 � I- El El TI - I� FI 71 111 08- 0..006 0.04�-/1 � 1 + I4 H41-� H 14 0.02- 0" 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Proposed 2019 07 (Type /// 24-hr 100 Year Rainfall=8.90" Prepared by {enter your company name here) Printed 8/13/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Page 47 Summary for Pond 8P: Underground Chambers Retention for PDAs-1, 2, 3, & 5 Inflow Area = 0.881 ac, 75.99% Impervious, Inflow Depth = 7.05" for 100 Year event Inflow = 6.79 cfs @ 12.07 hrs, Volume= 0.517 of Outflow = 0.89 cfs @ 12.59 hrs, Volume= 0.517 af, Atten= 87%, Lag= 31.2 min Discarded = 0.89 cfs @ 12.59 hrs, Volume= 0.517 of Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Peak Elev= 33.02' @ 12.59 hrs Surf.Area= 3,357 sf Storage= 7,053 cf Plug-Flow detention time= 56.3 min calculated for 0.517 of(100% of inflow) Center-of-Mass det. time= 56.2 min ( 823.3 - 767.1 ) Volume Invert Avail.Storage Storaqe Description #1A 29.70' 2,967 cf 34.75'W x 96.59'L x 3.50'H Field A 11,748 cf Overall -4,330 cf Embedded = 7,418 cf x 40.0% Voids #2A 30.20' 4,330 cf Lane Storm Keeper SK75 x 91 Inside#1 Effective Size= 44.7"W x 30.0"H => 6.61 sf x 7.081 = 46.8 cf Overall Size= 51.0"W x 30.0"H x 7.30'L with 0.22' Overlap 91 Chambers in 7 Rows Cap Storaqe= +5.2 cf x 2 x 7 rows = 73.4 cf 7,297 cf Total Available Storage Storage Group A created with Chamber Wizard Device Routinq Invert Outlet Devices #1 Discarded 29.70' 8.270 in/hr Exfiltration over Horizontal area Conductivity to Groundwater Elevation = 21.00' Discarded OutFlow Max=0.89 cfs @ 12.59 hrs HW=33.02' (Free Discharge) L1=Exfiltration ( Controls 0.89 cfs) 19 Coolidge Hill Rd - Watertown Proposed 2019 07 (Type /// 24-hr 100 Year Rainfall=8.90" Prepared by {enter your company name here) Printed 8/13/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 48 Pond 8P: Underground Chambers Retention for PDAs-1, 2, 3, & 5 - Chamber Wizard Field A Chamber Model = Lane Storm Keeper SK75(Lane StormKeeper) Effective Size= 44.7"W x 30.0"H => 6.61 sf x 7.081 = 46.8 cf Overall Size= 51.0"W x 30.0"H x 7.301 with 0.22' Overlap Cap Storage= +5.2 cf x 2 x 7 rows = 73.4 cf 51.0" Wide + 6.0" Spacing = 57.0" C-C Row Spacing 13 Chambers/Row x 7.08' Long +1.81' Cap Length x 2 = 95.59' Row Length +6.0" End Stone x 2 = 96.59' Base Length 7 Rows x 51.0" Wide + 6.0" Spacing x 6 + 12.0" Side Stone x 2 = 34.75' Base Width 6.0" Base + 30.0" Chamber Height + 6.0" Cover = 3.50' Field Height 91 Chambers x 46.8 cf + 5.2 cf Cap Volume x 2 x 7 Rows = 4,330.4 cf Chamber Storage 11,748.0 cf Field -4,330.4 cf Chambers = 7,417.6 cf Stone x 40.0% Voids = 2,967.0 cf Stone Storage Chamber Storage + Stone Storage = 7,297.4 cf= 0.168 of Overall Storage Efficiency = 62.1% Overall System Size = 96.59' x 34.75' x 3.50' 91 Chambers 435.1 cy Field 274.7 cy Stone 19 Coolidge Hill Rd - Watertown Proposed 2019 07 (Type /// 24-hr 100 Year Rainfall=8.90" Prepared by {enter your company name here) Printed 8/13/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Page 49 Pond 8P: Underground Chambers Retention for PDAs-1, 2, 3, & 5 Hydrograph ❑Inflow 0 6.79 cfs Discarded M � � I I Ii�filo�lAr��l-b!sb� �� 6� 'I 1 TIT IT I I Oeak Ibe" 31.012� �I -I t- I + I -+ Storage=7t,dt3 c 5� 1 I It 2� I I I III I � I III I I I I fi fi 0.89 cfs fi 1 o .r. ./... . ....i... .... .... ............... 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Proposed 2019 07 (Type /// 24-hr 100 Year Rainfall=8.90" Prepared by {enter your company name here) Printed 8/13/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Page 50 Summary for Pond 10P: Round Leaching Structure 01 Inflow Area = 0.058 ac, 5.00% Impervious, Inflow Depth = 1.13" for 100 Year event Inflow = 0.05 cfs @ 12.11 hrs, Volume= 0.005 of Outflow = 0.01 cfs @ 14.77 hrs, Volume= 0.005 af, Atten= 86%, Lag= 159.2 min Discarded = 0.01 cfs @ 14.77 hrs, Volume= 0.005 of Routing by Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Peak Elev= 38.52' @ 14.77 hrs Surf.Area= 28 sf Storage= 71 cf Plug-Flow detention time= 116.3 min calculated for 0.005 of(100% of inflow) Center-of-Mass det. time= 116.2 min ( 1,035.9 - 919.7 ) Volume Invert Avail.Storage Storage Description #1 36.00' 85 cf 6.00'D x 3.00'H Vertical Cone/Cylinder Device Routing Invert Outlet Devices #1 Discarded 36.00' 8.270 in/hr Exfiltration over Surface area Conductivity to Groundwater Elevation = 25.00' Discarded OutFlow Max=0.01 cfs @ 14.77 hrs HW=38.52' (Free Discharge) L1=Exfiltration ( Controls 0.01 cfs) Pond 10P: Round Leaching Structure 01 Hydrograph �� + 14 H I� I� H �I �I +- I 0.05� _ 10.05 cfs I i � ■Discarded 0.045� _ 1. 1 Ar a—b.�O�8��c� 3�6�5 2�_ 004 �I FI TI T T T S�tdrJadd=7�I 0.035_ �IIIIIIIIIII � N 0.03. — 0.025� c IIIIIIIIIII " 0.02� �I 0.015L'I 0.01-:-/ t-1 1- 1 J- 1 0.01 cfs 0.005�/ 0 ....... 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Proposed 2019 07 (Type /// 24-hr 100 Year Rainfall=8.90" Prepared by {enter your company name here) Printed 8/13/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 51 Summary for Link 20L: DPs-1, 2, 3, & 5: CB Rim near Arlington St. 0 Surcharge Elev.36.00 Inflow Area = 0.881 ac, 75.99% Impervious, Inflow Depth = 0.00" for 100 Year event Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 of Primary outflow = Inflow, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Link 20L: DPs-1, 2, 3, & 5: CB Rim near Arlington St. 0 Surcharge Elev.36.00 Hydrograph 1 � I ❑Primary Il41�l r A�eal=6.8611 ac IIIIIIIIIIIIIIIIIII I H I I H I I I I I I I I I I I Illllllllllllllllll 3 IIIIIIIIIIIIII � � � I � 0 LL 0.00 cfs 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) 19 Coolidge Hill Rd - Watertown Proposed 2019 07 (Type /// 24-hr 100 Year Rainfall=8.90" Prepared by {enter your company name here) Printed 8/13/2019 HydroCAD® 10.00-25 s/n 01087 ©2019 HydroCAD Software Solutions LLC Paqe 52 Summary for Link 21 L: DP-4: Surcharge Zero Elev.42.25 Inflow Area = 0.058 ac, 5.00% Impervious, Inflow Depth = 0.00" for 100 Year event Primary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 of Primary outflow = Inflow, Time Span= 0.00-30.00 hrs, dt= 0.02 hrs Link 21 L: DP-4: Surcharge Zero Elev.42.25 Hydrograph 1 I I ` ■Primary i4�ea'=b.6�8 �C' O LL 0.00 cfs 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Time (hours) STORMWATER/DRAINAGE REPORT CROWE July 09, 2019 Landscape Architects and Civil Engineers 19 Coolidge Hill Road Winchester, Massachusetts Watertown, Massachusetts CONSTRUCTION PHASE POLLUTION PREVENTION PLAN CROWE Construction Phase Pollution Prevention Plan John G.Crowe Associates,Inc. 19 Coolidge Hill Road Landscape Architects and Civil Engineers Watertown, Massachusetts Construction Phase Pollution Prevention Plan (CPPPP) For construction activities: 19 Coolidge Hill Road at 19 Coolidge Hill Road Watertown, Massachusetts Prepared by: CROWE John G. Crowe Associates, Inc. Landscape Architects and Civil Engineers 39 Holton Street Winchester, MA 01890 781-570-2365 CPPPP preparation date: July 9, 2019 Estimated project construction dates: Start: Fall, 2019 Completion: Fall, 2020 CROWE Construction Phase Pollution Prevention Plan John G.Crowe Associates,Inc. 19 Coolidge Hill Road Landscape Architects and Civil Engineers Watertown, Massachusetts THIS DOCUMENT WILL NEED TO BE UPDATED WITH CONTRACTOR INFORMATION AND NECESSARY REVISIONS WHICH MAY BECOME EVIDENT PRIOR TO CONSTRUCTION START. SECTION 1: CONTACT INFORMATION/RESPONSIBLE PARTIES 1.1 Operator(s)/Subcontractor(s) Operator(s): Contractors To Be Determined Address Tel: Subcontractor(s): Emergency 24-Hour Contact: Name and email Eric Vogel Blue Hawk Investments - Project Executive 617-470-5274 1.2 Stormwater Team Operators and Contractors Listed above. Stormwater Inspector: Aaron Z. Alpert, aalpert(a)icrowe.com, 781-570-2365 ext. 230 Charles Scott Doty, csdotv(a)icrowe.com, 781-570-2365 ext. 212 Donald A. Provencher, P.E. John G. Crowe Associates, Inc. 39 Holton Street Winchester, Massachusetts 01890 Page 1 CROWE Construction Phase Pollution Prevention Plan John G.Crowe Associates,Inc. 19 Coolidge Hill Road Landscape Architects and Civil Engineers Watertown, Massachusetts SECTION 2 CONSTRUCTION NARRATIVE 2.1 Nature of the Construction Activities General Description of Project The Project Proponent, 19 Coolidge Hill Road, LLC proposes to construct a Self Service Storage Facility. Size of Construction Project Construction disturbance area: 41,000 s.f. Maximum area disturbed at any one time: approximately 25,000 s.f. 2.2 Sequence and Estimated Dates of Construction Activities The proposed project is commercial in nature and is anticipated to be constructed in three general phases, site preparation and demolition; underground construction; and above ground construction. The construction of the Project is expected to take 15 months with the following sequence of major site work elements: Site Preparation and Demolition ■ Installation of erosion and sediment controls. ■ Establishment of construction controls ■ Careful and minimal tree removal and pruning: Full removal of trees on the property which cannot be saved. Above ground removal of 6 or less trees along the park edge which are leaning on the building side or roof. Pruning of park edge tree limbs hanging over site for construction phase and long-term public safety. ■ Careful building demolition with selective retention of existing of zero-lot-line foundation walls to prevent undermining of adjacent public sidewalk and park. Underground Construction ■ Installation of drainage system components needed to contain and control construction phase stormwater. ■ Excavation and installation of utilities, building footings and foundations. ■ Pave binder course to stabilize site for building erection.t curbing where needed. ■ Seed and stabilize landscape areas. Above-ground Construction ■ Construct building super-structure and interior. ■ Construct finish sitework. 2.3 Construction Hours Construction of the Project will conform to all local, state, and federal laws limiting hours of active noise producing work and employ all reasonable means to minimize inconvenience to residents and businesses in the general area. Page 2 CROWE Construction Phase Pollution Prevention Plan John G.Crowe Associates,Inc. 19 Coolidge Hill Road Landscape Architects and Civil Engineers Watertown, Massachusetts SECTION 3: EROSION AND SEDIMENT CONTROLS The Erosion and Sediment Controls represent the suggested best management practices proposed for the project. Erosion and sedimentation control as well as effective methodologies and measures are described in this CPPPP. Many, if not all measures described, will be required. 3.1 Perimeter Controls General The use of erosion and sediment controls are mandatory and must be employed to minimize impacts to adjacent areas during construction. If sediment escapes the construction site, off-site accumulations of sediment must be removed at a frequency sufficient to minimize off-site impacts. The control practices which are required to minimize stormwater pollution during construction must remain functional until disturbed areas have been stabilized. Erosion control products are to be installed and maintained in accordance with manufacturer's specifications and good engineering practices. The most important aspects of controlling erosion and sedimentation are limiting the extent of sediments arriving at drainage structures which are up-gradient from wetland and water resources. These fundamental principles will be the key factors in the contractor's control of erosion on the project site. As needed, the contractor will construct temporary barriers and settling areas preventing sediment laden stormwater from reaching catch basins or discharge points to wetlands. The contractor is responsible for the maintenance and repair of all erosion control devices on-site. All erosion control devices will be regularly inspected. At no time will silt-laden water be allowed to enter off-site drainage systems. Any runoff from disturbed surfaces will be directed through a sedimentation process prior to being discharged from the site. The contractor will establish a staging area for the overnight storage of equipment and stockpiling of materials. In the staging area, the contractor will have a stockpile of materials required to control erosion on- site to be used to supplement or repair erosion control devices. These materials will include, but are not limited to straw wattles, straw bales, silt fence, erosion control matting, and washed crushed stone. As mentioned previously, erosion and sedimentation controls will be employed to minimize the erosion and transport of sediment off-site during the earthwork and construction phases of the Project. Erosion and sedimentation control measures will be installed prior to site excavation or disturbance and will be maintained throughout the construction period. The contractor is responsible for erosion control on the site and will utilize supplemental erosion control measures to supplement the erosion controls shown on the plans for this project to work with his day to day operations at the site. Primary erosion control techniques proposed include straw bale and wattle barriers, silt fence barriers, inlet sediment traps, a stabilized construction entrance, temporary diversion channels, and temporary sedimentation ponds when applicable. A detailed description of each technique is discussed below. Page 3 CROWE Construction Phase Pollution Prevention Plan John G.Crowe Associates,Inc. 19 Coolidge Hill Road Landscape Architects and Civil Engineers Watertown, Massachusetts During the growing season, slope stabilization will be achieved by applying topsoil followed by seeding and mulching as soon as final grades are achieved. Organic mulching, jute netting, geo- textiles, or a combination will be used to stabilize slopes completed outside of the growing season. Specific Perimeter Controls Perimeter Control# 1 - Silt Fence Straw Bale or Wattle Barriers ■ Erosion control barriers (silt fences or straw bale dike) will be installed prior to the start of construction. These barriers will remain in place until all tributary surfaces have been fully stabilized. Installation ■ Straw bale or wattle barriers will be placed to trap sediment transported by runoff before it reaches the drainage system or leaves the construction site. In areas where high runoff velocities or high sediment loads are expected, silt fencing may be installed adjacent to the straw bale barriers. This semi-permeable barrier made of a synthetic porous fabric will provide additional protection. The silt fences and straw bale barrier will be replaced as determined by periodic field inspection. The underside of straw bales will be kept in close contact with the earth and reset as necessary. Maintenance Requirements ■ Straw barriers and siltation fences will be maintained and cleaned until all disturbed areas are stabilized, pavements installed and landscaping completed. ■ Remove sediment before it has accumulated to one-third of the above-ground height of any perimeter control. Perimeter Control# 2— Drain Svstem Protection ■ Silt Sack sediment traps supplemented with straw bale erosion checks will be installed at drainage structures and maintained and cleaned until slopes have healthy stands of grass. ■ Catch basins, drain manholes, and storm drain pipes will be cleaned of sediment and debris after the completion of construction. Sediment collected in structures will be disposed of properly and covered, if stored on-site. Installation ■ Until tributary areas are stabilized, catch basin inlets will be filtered with a Silt sacks. If intense rainfall is predicted before all tributary areas are stabilized, erosion control measures will be reinforced for the duration of the storm. Downstream areas will be inspected and any sediment removed at the end of the storm. ■ Unfiltered water will not be allowed to enter pipes from un-stabilized surfaces. ■ Trench excavation will be limited to the minimum length required for daily pipe installation. All trenches will be backfilled as soon as possible. The upper ends of pipes will be sealed or Page 4 CROWE Construction Phase Pollution Prevention Plan John G.Crowe Associates,Inc. 19 Coolidge Hill Road Landscape Architects and Civil Engineers Watertown, Massachusetts closed nightly. Maintenance Requirements ■ During construction of the site, silt-laden waters should be intercepted prior to reaching catch basins. Any gross depositions of materials on paved surfaces will be removed by sweeping. ■ All paved areas will be swept on a weekly basis, as permitted by weather, during the construction period. ■ Catch basins should be inspected monthly and cleaned as required. 3.2 Stockpiled Sediment or Soil General ■ Locate the piles outside of any natural buffers and physically separated from other stormwater controls implemented using the guidance provided on the project plans. ■ Protect from contact with stormwater(including run-on) using a temporary perimeter sediment barrier. See below for specific types. ■ Stockpile of topsoil or subsoil shall be seeded with annual rye grass if left over 30 days to minimize erosion or siltation. ■ Do not hose down or sweep soil or sediment accumulated on pavement or other impervious surfaces into any stormwater conveyance (unless connected to a sediment basin, sediment trap, or similarly effective control), storm drain inlet, or surface water. ■ Unless infeasible, contain and securely protect from wind. Installation ■ Install straw bale barrier with silt fencing as needed to control limits of stockpiles. ■ On pavement areas use straw wattles backed by masonry blocks every 4 feet, set at a distance of at least one-fourth the height of the stockpile or a similar method reviewed and approved by the stormwater inspector. Maintenance Requirements ■ Do not hose down or sweep soil or sediment accumulated on pavement or other impervious surfaces into any stormwater conveyance (unless connected to a sediment basin, sediment trap, or similarly effective control), storm drain inlet, or surface water. 3.3 Topsoil General ■ All topsoil encountered during the trench excavations shall be stockpiled in small, easy to manage piles near the areas where it will be reinstalled after pipes and conduit are installed. Page 5 CROWE Construction Phase Pollution Prevention Plan John G.Crowe Associates,Inc. 19 Coolidge Hill Road Landscape Architects and Civil Engineers Watertown, Massachusetts 3.4 Soil Compaction General ■ In areas of the site where final vegetative stabilization will occur or where infiltration practices will be installed, vehicle and equipment use is restricted in these locations to avoid soil compaction. ■ Immediately prior to dumping and spreading the topsoil, the sub grade shall be loosened by disking, or by scarifying to a depth of at least two inches, to permit bonding of the topsoil to the sub grade where compaction has occurred. 3.5 Catch Basin Inlets General ■ Install inlet protection measures that remove sediment from discharge prior to entry into catch basin inlets and grates in proximate down gradient locations.. Specific Catch Basin Inlet Controls Storm Drain Inlet Control# 1 — Silt Sack ■ Filter catchments placed under catch basin grates shall be "Silt Sack", manufactured by ACF Environmental, or approved equal, sized as required for individual catch basin grates. Silt fence fabric shall not be used in catch basins. Maintenance Requirements ■ Clean, or remove and replace, the protection measures as sediment accumulates, the filter becomes clogged, and/or performance is compromised. Where there is evidence of sediment accumulation adjacent to the inlet protection measure, you must remove the deposited sediment by the end of the same work day in which it is found or by the end of the following work day if removal by the same work day is not feasible. 3.6 Site Stabilization All disturbed surfaces will be stabilized a minimum of 14 days after construction in any portion of the project site is completed or is temporarily halted, unless additional construction is intended to be initiated within 21 days. The Contractor will not disturb more area than can be stabilized within 14 days unless the area is to remain active. The Contractor will not disturb more area than can be stabilized within the same construction season. Site Stabilization Practice (only use this if you are not located in an arid, semi-arid, or drought- stricken area) ® Vegetative ❑ Non-Vegetative ❑ Temporary❑ Permanent Description of Practice • Scattered bare spots, none of which are larger than 72 square inches, will be allowed up to a maximum of two percent of any lawn area. After the grass has started growing, all areas and Page 6 CROWE Construction Phase Pollution Prevention Plan John G.Crowe Associates,Inc. 19 Coolidge Hill Road Landscape Architects and Civil Engineers Watertown, Massachusetts parts of areas which fail to show a uniform stand of grass, for any reason whatsoever, shall be reseeded and such areas and parts of areas shall be reseeded repeatedly until all areas are covered with a satisfactory growth of grass. Maintenance Requirements • The Contractor shall be held responsible for maintenance of lawns, including watering, weeding, mowing, fertilizing and replanting as necessary to establish a uniform stand of the specified grasses until acceptance. SECTION 4: POLLUTION PREVENTION STANDARDS 4.1 Potential Sources of Construction Stormwater Pollution The potential sources of pollution from the project besides sediments resulting from earth excavation and grading activities is the fueling of construction vehicles and spills of materials typical to a construction site. 4.2 Spill Prevention and Response The Contractor will train all personnel in the proper handling and cleanup of spilled materials. No spilled hazardous materials or hazardous wastes will be allowed to come in contact with storm water discharges from the property. If such contact occurs, the storm water discharge will be contained on site until appropriate measures in compliance with state and federal regulations are taken to dispose of such contaminated storm water. It shall be the responsibility of the job site superintendent to properly train all personnel in spill prevention and clean up procedures. In order to minimize the potential for a spill of hazardous materials to come into contact with storm water, the following steps will be implemented: • All materials with hazardous properties (such as pesticides, petroleum products, fertilizers, detergents, construction chemicals, acids, paints, paint solvents, cleaning solvents, additives for soil stabilization, concrete curing compounds and additives, etc.)will be stored in a secure location, with their lids on, preferably under cover, when not in use. • During construction, liquid petroleum products and other hazardous materials with the potential to contaminate groundwater may not be stored or handled in areas of the site draining to an infiltration area. An "infiltration area" is any area of the site that by design or as a result of soils, topography and other relevant factors accumulates runoff that infiltrates into the soil. Dikes, berms, sumps, and other forms of secondary containment that prevent discharge to groundwater may be used to isolate portions of the site for the purposes of storage and handling of these materials • The minimum practical quantity of all such materials will be kept on the job site at all times. ■ A spill control and containment kit (containing, for example, absorbent materials, acid neutralizing powder, brooms, dust pans, mops, rags, gloves, goggles, plastic and metal trash containers, etc.) will be provided at the storage site. Catch basin inlet cover blankets and inflatable pipe plugs will be used to seal the openings in the outlet control structure and isolate product in the water quality structures should a spill occur. Page 7 CROWE Construction Phase Pollution Prevention Plan John G.Crowe Associates,Inc. 19 Coolidge Hill Road Landscape Architects and Civil Engineers Watertown, Massachusetts • Manufacturer's recommended methods for spill cleanup will be clearly posted and site personnel will be trained regarding these procedures and the location of the information and cleanup supplies. In the event of a spill, the following procedures should be followed: ■ All spills will be cleaned up immediately after discovery. • The spill area will be kept well ventilated and personnel will wear appropriate protective clothing to prevent injury from contact with the hazardous substances. • The project manager and the Engineer of Record will be notified immediately. • Spills of toxic or hazardous materials will be reported to the appropriate federal, state, and/or local government agency, regardless of the size of the spill. • If the spill exceeds a Reportable Quantity, the Watertown Health Department must be notified within two (2) calendar days of knowledge of the discharge to provide a description of the release, the circumstances leading to the release, and the date of the release. The plans must identify measures to prevent the recurrence of such releases and to respond to such releases. The job site superintendent will be the spill prevention and response coordinator. He will designate the individuals who will receive spill prevention and response training. These individuals will each become responsible for a particular phase of prevention and response. The names of these personnel will be posted in the material storage area and in the office trailer onsite. 4.3 Fueling and Maintenance of Equipment or Vehicles General ■ To provide and effective means of eliminating the discharge of spilled or leaked chemicals, including fuel, from the area where these activities will take place. Specific Pollution Prevention Practices Pollution Prevention Practice # 1 Description ■ The Operator shall provide a plan for the areas which will be designated on site to refuel or maintain equipment used on site. The fueling areas will include localized drainage containment in case of spills as described below. Installation Schedule ■ September 2019 Maintenance Requirements • The fueling areas will be inspected and cleaned weekly. • The wheel wash station will be inspected and cleaned weekly. Page 8 CROWE Construction Phase Pollution Prevention Plan John G.Crowe Associates,Inc. 19 Coolidge Hill Road Landscape Architects and Civil Engineers Watertown, Massachusetts 4.4 Storage, Handling, and Disposal of Construction Products, Materials, and Wastes • All waste materials will be collected and stored in accordance with state and federal law in an appropriately covered container and/or securely lidded metal dumpster. • All trash and construction debris from the site will be deposited in the dumpster. No construction waste materials will be buried on site. All personnel will be instructed regarding the correct procedures for waste disposal. • All waste dumpsters and roll-off containers will be located in an area where the likelihood of the containers contributing to storm water discharges is negligible. If required, additional BMPs must be implemented, such as sandbags around the base, to prevent wastes from contributing to storm water discharges. 4.4.1 Building Products (Note: Examples include asphalt sealants, adhesives, concrete admixtures.) General • An effort will be made to store only enough products required to do the job. All materials stored on-site will be stored in a neat, orderly manner in their appropriate containers and, if possible under a roof or other enclosure • Products will be kept in their original containers with the original manufacturer's label • Substances will not be mixed with one another unless recommended by the manufacture • Whenever possible, all of a product will be used up before disposing of the container • Manufacturer's recommendations for proper use and disposal will be followed • The site superintendent will inspect daily to ensure proper use and disposal of materials 4.4.2 Diesel Fuel, Oil, Hydraulic Fluids, Other Petroleum Products, and Other Chemicals Specific Pollution Prevention Practices Pollution Prevention Practice # 1 Description ■ Store chemicals in water-tight containers, and provide either (1) cover (e.g., plastic sheeting or temporary roofs)to prevent these containers from coming into contact with rainwater, or(2) a similarly effective means designed to prevent the discharge of pollutants from these areas (e.g., spill kits), or provide secondary containment (e.g., spill berms, decks, spill containment pallets). Maintenance Requirements ■ Clean up spills immediately, using dry clean-up methods where possible, and dispose of used materials properly. Do not clean surfaces or spills by hosing the area down. Eliminate the source of the spill to prevent a discharge or a continuation of an ongoing discharge. Page 9 CROWE Construction Phase Pollution Prevention Plan John G.Crowe Associates,Inc. 19 Coolidge Hill Road Landscape Architects and Civil Engineers Watertown, Massachusetts 4.4.3 Hazardous or Toxic Waste General These practices will be used to reduce the risks associated with hazardous materials. Material Safety Data Sheets (MSDSs) for each substance with hazardous properties that is used on the job site will be obtained and used for the proper management of potential wastes that may result from these products. An MSDS will be posted in the immediate area where such product is stored and/or used and another copy of each MSDS will be maintained in the CPPPP file at the job site construction trailer office. Each employee who must handle a substance with hazardous properties will be instructed on the use of MSDS sheets and the specific information in the applicable MSDS for the product they are using, particularly regarding spill control techniques. Specific Pollution Prevention Practices Pollution Prevention Practice # 1 Description ■ Products will be kept in original containers unless they are not re-sealable ■ Original labels and material safety data will be retained; they contain important product information ■ If surplus product must be disposed of, manufacture's or local and State recommended methods for proper disposal will be followed Maintenance Requirements • All hazardous waste material will be disposed of by the Contractor in the manner specified by local, state, and/or federal regulations and by the manufacturer of such products. Site personnel will be instructed in these practices by the job site superintendent, who will also be responsible for seeing that these practices are followed. 4.4.4 Construction and Domestic Waste General • All waste materials will be collected and stored in accordance with state and federal law in an appropriately covered container and/or securely lidded metal dumpster. ■ All trash and construction debris from the site will be deposited in the dumpster. No construction waste materials will be buried on site. All personnel will be instructed regarding the correct procedures for waste disposal. ■ All waste dumpsters and roll-off containers will be located in an area where the likelihood of the containers contributing to storm water discharges is negligible. If required, additional BMPs must be implemented, such as sandbags around the base, to prevent wastes from contributing to storm water discharges. 4.5 Sanitary Waste Specific Pollution Prevention Practices Page 10 CROWE Construction Phase Pollution Prevention Plan John G.Crowe Associates,Inc. 19 Coolidge Hill Road Landscape Architects and Civil Engineers Watertown, Massachusetts Pollution Prevention Practice # 1 Description ■ All sanitary waste units will be located in an area where the likelihood of the unit contributing to storm water discharges is negligible. If required, additional BMP's must be implemented, such as sandbags around the base, to prevent wastes from contributing to storm water discharges. ■ Position portable toilets so that they are secure and will not be tipped or knocked over. Maintenance Requirements • All sanitary waste will be collected from the portable units a minimum of three times per week by a licensed portable facility provider in complete compliance with local and state regulation. SECTION 5: INSPECTION AND CORRECTIVE ACTION 5.1 Inspection Personnel and Procedures Personnel Responsible for Inspections The General Permit Conditions require routine inspections of the site and careful documentation of events and conditions. The following inspection activities will be completed by a qualified, designated site monitor. Inspection Schedule Specific Inspection Frequency ■ Erosion control, sedimentation prevention, and stormwater management measures will be inspected daily by the Operator's designated monitor, and at least once per week by the Stormwater Inspector throughout the construction period. ■ All controls, outfalls, and potential problem areas will also be inspected within 24 hours of any storm exceeding 0.25 inches of precipitation. Inspection Report Forms ■ Copies of the attached Inspection Report Forms shall be used. Personnel Responsible for Corrective Actions ■ General Contractor Corrective Action Forms ■ Appendix D for Corrective Action Forms Page 11 CROWE Construction Phase Pollution Prevention Plan John G.Crowe Associates,Inc. 19 Coolidge Hill Road Landscape Architects and Civil Engineers Watertown, Massachusetts 5.2 Corrective Action 5.3 Delegation of Authority Duly Authorized Representative(s) or Position(s): To be determined LIST OF CPPPP APPENDICES CPPPP Inspection Report Form CPPPP Corrective Action Form CPPPP Amendment Log Operations and Maintenance Plan Page 12 0 \ 0 \ & 0)� 9 ƒ fLL ) 0 7 ± 2 \ \ § 2 \ f CL E % \ _0 .0 c a. 0U ƒ \ 2 a. § e W / � / \ 0 \ \ � E \ ƒ \ \ / Z % _ / » k \ § E / / \ / \ \ 0 / 2 f & - ƒ a @ \ -a � / : E E \ f ) § Z Uco } \ � R ❑ / $ E ) \ -a ° ± _ -0 G § @ ° co \ CO U) % § ) � ® 2 $ _ u % ! � » 0 = _ 7 0 \ �£ m t = % t / / f \ ® X- cn a. cc Q) " \ n / / - \ } 2 \ \ \ e _ 2 - - 0 3 k Z5 = b � m £ ( - "0 / @ 5 » § 4 \ \ § ƒ \ k \ \ o � ° t o ■ t : / _ ° \ E 2 G / \ E / £ § } [ m cn3 (n ❑ ° ° / ( _ § - ® c \ j �/ m2 \ / } \ 3 � » / { 2 a 2 / / 4 3 ® � » ❑ ; ƒ s m o % � b � � z 7 2 ° 0 » \ ) Ee � / 3E % \ GE m ) E § ; e - \ 7 = 9 ° 2 § 2 0 � - f 2 \ mr- ; � - _ » % @ �5 \ ` 02 E _ \ _ -0 0) @E / 0 ` } / k \ / k ±% EGA ] � _ e o 7 $ m = = : . � 7 £ off = % u » mau} E- = = a R 3 � \ \ j \ � e § ' _ @ - (❑ ❑ R 23 % mom❑ & o .2 \ E ° tee � � @ � CLo / : �4- ( - % / 2 / E _ \ 2 § 2 7 \ } _ / � _ � 2 � o © 2 / U) E o { £ 2 ° ° \ * 0 ( § # 222 / § & 2 } fE00 } \ k � / kkk $ � 0) � kG / \ u 2 j t E L S 3 E m 2 G / / \ \ 2 ƒ c ƒ � � 7 k 2 / / / A/ � § 77 �= . 0 \ 05 / � 0 $ $ 2 2 ƒ❑❑❑ ' U) 0i� , � \ kodkkk k k / J , , , § d % k / \ / § kCLU / / / § � « j O a) U P- O O = U c o � a) N c E m m N 07 a) m m > M U O � O � � � � m m 0 oU 3 EuU) (L3) 0o a } o O a� a� N0 � M m O IL (n (n (n (n (n (n (n (n O C ` CL 7 >� a) N O a) N O N N N O N 07 N Z > O O O O O O O O L -O .� L r C c C C C C c C a) � O Q p N r a) 0 a) a) a� a) a> a� c E w a � O c c c c c c C �� 0 a .c � o ^ o O d Z W W W W W W W W (D �, O •U V O) o m IL W n � M U L Q O W L U 0 V1 a) N O U D U V d m a) O Zu ° � � -� > 0U W � fi) ct U � m O ) U �i 2LL O� 0a U a aO) 2 , Uwmc7 C oL a> .��_•, is io is io m io � a�i .- 0 0 E o N .=_ 0 L L L L L L L L �`y O (n U ' m C O a) d (a LO C C C C C C C C "" �• C N C O � O (n U W W W W W W W W U C O E c •— _ N 'a m f6 L O cu m � -0 O a) 0 + = E cn E Z Z Z Z Z Z Z Z ) m O r � ❑ E] E] ❑ E] E] Li Li3 Co N N _ L W m U) (n cn (n (n cn (n U) m m a) E O U Q ❑ ❑ ❑ ❑ ❑ ❑ ❑ ❑ c 0 — in CO` LO tll m O ) (D m L m 7 N d a) O O O O O O O O a. 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Basic Information Owner: 19 Coolidge Hill Owner, LLP 24-hour Contact: Eric Vogel, Tel. 617-470-5274 Post-construction maintenance shall be the responsibility of the Owner. The following drainage system components, BMPs, and LID techniques are specified for this property. ■ New vehicular pavement and curbing to capture vehicular pavement run-off ■ Area drains to capture run-off from landscape areas and pedestrian pavements ■ Water Quality Catch Basins for vehicular pavement drainage (proprietary capture and pre- treatment structures) ■ Underground Retention/Infiltration Structures O&M Activities 1. Pavement Cleaning: On grade paved areas shall be swept twice each year. One, at the end of the Winter (freezing)weather to remove sediments in order to reducing the amount of sediments that the drainage system will have to remove from the runoff during Spring rain season. Two, at the end of Autumn after most leaves have fallen to remove summer sediments and leaf debris for optimal functionality of the drainage system during the rainy and snowy Winter months. 2. Snow Removal: Snow removal vehicle operator may not place snow piles on drainage system catch structure grates. Grates shall be kept free of snow storage so that snow and ice melt is not prevented from free drainage to and into the grates. 3. Landscaped Areas: a. Fertilization shall only be performed by a Massachusetts Licensed Commercial Fertilizer Applicator to protect against over fertilization and excess fertilization practices. Fertilizers shall meet current governmental regulations regarding phosphorus content. Fertilizers shall not be applied if there is a major rainfall event (greater than 0.25 inches) predicted within 48 hours of an application. b. Fertilization of grass areas shall be performed by commercial with drop or direct downward spray equipment. Fertilization of other landscape areas (plantings, shrubs, and trees) shall be done with "target" placement in or on the root zone. Broad-cast spreaders or wide spray systems which are more prone to excess coverage spread beyond landscape areas onto pavements, shall not be used. Page 1 of 2 CROWE Operations and Maintenance Plan John G.Crowe Associates,Inc. 19 Coolidge Hill Road Landscape Architects and Civil Engineers Watertown, Massachusetts C. Watering of landscape areas shall be limited to "formal planting beds" and lawns adjacent to the building. 4. Water Quality Catch Basins (Proprietary Pre-treatment Structures): Water Quality Catch Basins shall be inspected at four times during the first year of service to determine if they require quarterly inspection in the future. If the basin collection sumps are found to be more than half full at more than two of the first year inspections quarterly inspections should continue indefinitely until this threshold is not repeated in a following year. If the increased inspection threshold is not exceeded, inspections shall be twice yearly: one, at the end of the freezing winter season; and two, before the start of the next winter season after the deciduous fall foliage has dropped. Water Quality Catch Basin cleaning shall be in strict conformance with the manufacturer's recommendations using vac-trucks. Material shall be removed and disposed of in accordance with all applicable regulations. 5. The underground retention/infiltration structures shall be inspected twice a year for signs of accumulated water or debris. Implemented appropriate corrective actions if any issues are discovered during the inspection. Reportinq Responsibilities The Owner of the facility shall prepare and keep complete annual records of all maintenance activities and reports and make these records available to City of Watertown upon request. 19 Coolidge Hill Owner, LLP signature Print name and title of authorized corporate representative Page 1