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08-021 (9) PROPOS-2 Type III 24-hr Rainfall=6.40" Prepared by The Berkshire Design Group, Inc. Page 12 HydroCADO 6.00 s/n 000752 © 1986-2001 Applied Microcomputer Systems 2/6/03 Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Pond 1P: (new node) Inflow = 3.45 cfs @ 12.07 hrs, Volume= 0.292 of Outflow = 2.47 cfs @ 12.16 hrs, Volume= 0.290 af, Atten= 28%, Lag= 5.1 min Primary = 2.47 cfs @ 12.16 hrs, Volume= 0.290 af Routing by Stor-Ind method, Time Span= 5.00-20.00 hrs, dt=0.05 hrs Peak Elev= 98.14' Storage= 1,273 cf Plug-Flow detention time=11.2 min calculated for 0.289 af (99%of inflow) Storage and wetted areas determined by Prismatic sections Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 94.50 350 0 0 99.00 350 1,575 1,575 Primary OutFlow (Free Discharge) 't-1=Culvert -2=Orifice/Grate —3=Orifice/Grate —4=Orifice/Grate # Routing Invert Outlet Devices 1 Primary 94.60' 12.0" x 33.0' long Culvert RCP, square edge headwall, Ke= 0.500 Outlet Invert= 93.80' S= 0.0242 '1 n= 0.010 Cc= 0.900 2 Device 1 96.60' 5.0" Vert. Orifice/Grate C= 0.600 3 Device 1 94.60' 6.0" Vert. Orifice/Grate C= 0.600 4 Device 1 99.00' 12.0" Horiz. Orifice/Grate Limited to weir flow C= 0.600 Pond ecb: ecb Inflow = 2.47 cfs @ 12.16 hrs, Volume= 0.290 of Primary = 2.47 cfs @ 12.16 hrs, Volume= 0.290 af, Atten=0%, Lag= 0.0 min Routing by Stor-Ind method, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs PROPOS-2 Type III 24-hr Rainfall=6.40" Prepared by The Berkshire Design Group, Inc. Page 11 HydroCADO 6.00 s/n 000752 ©1986-2001 Applied Microcomputer Systems 2/6/03 Subcatchment 1S: PAVED Runoff = 2.64 cfs @ 12.07 hrs, Volume= 0.198 af Runoff by SCS TR-20 method, UH=SCS, Time Span=5.00-20.00 hrs, dt= 0.05 hrs Type III 24-hr Rainfall=6.40" Area (ac) CN Description 0.418 98 Paved parking &sidewalks Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment b: b Runoff = 0.18 cfs @ 12.35 hrs, Volume= 0.033 af Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Type Ill 24-hr Rainfall=6.40" Area (ac) CN Description 0.214 39 >75% Grass cover, Good, HSG A 0.860 36 Woods, Fair, HSG A 1.074 37 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 4.5 46 0.2400 0.2 Sheet Flow, Woods: Light underbrush n= 0.400 P2=2.90" 0.3 79 0.0400 4.1 Shallow Concentrated Flow, Paved Kv= 20.3 fps 0.6 235 0.0940 6.2 Shallow Concentrated Flow, Paved Kv= 20.3 fps 5.4 360 Total Subcatchment bldg: bldg Runoff = 0.80 cfs @ 12.07 hrs, Volume= 0.060 af Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Type Ill 24-hr Rainfall=6.40" Area (ac) CN Description 0.127 98 Paved parking & roofs PROPOS-2 Type III 24-hr Rainfall=6.40" Prepared by The Berkshire Design Group, Inc. Page 10 HydroCAD®6.00 s/n 000752 ©1986-2001 Applied Microcomputer Systems 2/6/03 Time span=5.00-20.00 hrs, dt=0.05 hrs, 301 points Runoff by SCS TR-20 method, UH=SCS, Type III 24-hr Rainfall=6.40" Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment 1S: PAVED Tc=5.0 min CN=98 Area=0.418 ac Runoff=2.64 cfs 0.198 af Subcatchment b: b Tc=5.4 min CN=37 Area=1.074 ac Runoff=0.18 cfs 0.033 af Subcatchment bldg: bldg Tc=5.0 min CN=98 Area=0.127 ac Runoff=0.80 cfs 0.060 af Pond 1 P: (new node) Peak Storage= 1,273 cf Inflow=3.45 cfs 0.292 af Primary=2.47 cfs 0.290 of Outflow=2.47 cfs 0.290 of Pond ecb: ecb Inflow=2.47 cfs 0.290 af Primary=2.47 cfs 0.290 of Runoff Area = 1.619 ac Volume =0.292 af Average Depth = 2.16" PROPOS-2 Type III 24-hr Rainfall=4.40" Prepared by The Berkshire Design Group, Inc. Page 9 HydroCADO 6.00 s/n 000752 ©1986-2001 Applied Microcomputer Systems 2/6/03 Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Pond 1 P: (new node) Inflow = 2.36 cfs @ 12.07 hrs, Volume= 0.179 af Outflow = 1.68 cfs @ 12.16 hrs, Volume= 0.177 af, Atten=29%, Lag= 5.2 min Primary = 1.68 cfs @ 12.16 hrs, Volume= 0.177 af Routing by Stor-Ind method, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Peak Elev= 97.01' Storage= 878 cf Plug-Flow detention time=13.8 min calculated for 0.177 af (99%of inflow) Storage and wetted areas determined by Prismatic sections Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 94.50 350 0 0 99.00 350 1,575 1,575 Primary OutFlow (Free Discharge) t1=Culvert t 2=Orifice/Grate —3=Orifice/G rate —4=Orifice/Grate # Routing Invert Outlet Devices 1 Primary 94.60' 12.0" x 33.0' long Culvert RCP, square edge headwall, Ke= 0.500 Outlet Invert= 93.80' S= 0.0242 '/' n= 0.010 Cc= 0.900 2 Device 1 96.60' 5.0" Vert. Orifice/Grate C= 0.600 3 Device 1 94.60' 6.0" Vert. Orifice/Grate C= 0.600 4 Device 1 99.00' 12.0" Horiz. Orifice/Grate Limited to weir flow C= 0.600 Pond ecb: ecb Inflow = 1.68 cfs CO 12.16 hrs, Volume= 0.177 af Primary = 1.68 cfs @ 12.16 hrs, Volume= 0.177 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind method, Time Span=5.00-20.00 hrs, dt= 0.05 hrs PROPOS-2 Type III 24-hr Rainfall=4.40" Prepared by The Berkshire Design Group, Inc. Page 8 HydroCAD®6.00 s/n 000752 ©1986-2001 Applied Microcomputer Systems 2/6/03 Subcatchment 1S: PAVED Runoff = 1.81 cfs @ 12.07 hrs, Volume= 0.135 af Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Type III 24-hr Rainfall=4.40" Area (ac) CN Description 0.418 98 Paved parking &sidewalks Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment b: b Runoff = 0.01 cfs @ 15.45 hrs, Volume= 0.003 af Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-20.00 hrs, dt=0.05 hrs Type III 24-hr Rainfall=4.40" Area (ac) CN Description 0.214 39 >75% Grass cover, Good, HSG A 0.860 36 Woods, Fair, HSG A 1.074 37 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 4.5 46 0.2400 0.2 Sheet Flow, Woods: Light underbrush n= 0.400 P2=2.90" 0.3 79 0.0400 4.1 Shallow Concentrated Flow, Paved Kv=20.3 fps 0.6 235 0.0940 6.2 Shallow Concentrated Flow, Paved Kv=20.3 fps 5.4 360 Total Subcatchment bldg: bldg Runoff = 0.55 cfs @ 12.07 hrs, Volume= 0.041 af Runoff by SCS TR-20 method, UH=SCS, Time Span=5.00-20.00 hrs, dt= 0.05 hrs Type III 24-hr Rainfall=4.40" Area (ac) CN Description 0.127 98 Paved parking & roofs PROPOS-2 Type III 24-hr Rainfall=4.40" Prepared by The Berkshire Design Group, Inc. Page 7 HydroCAD®6.00 s/n 000752 ©1986-2001 Applied Microcomputer Systems 2/6/03 Time span=5.00-20.00 hrs, dt=0.05 hrs, 301 points Runoff by SCS TR-20 method, UH=SCS, Type III 24-hr Rainfall=4.40" Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment 1S: PAVED Tc=5.0 min CN=98 Area=0.418 ac Runoff= 1.81 cfs 0.135 of Subcatchment b: b Tc=5.4 min CN=37 Area=1.074 ac Runoff=0.01 cfs 0.003 of Subcatchment bldg: bldg Tc=5.0 min CN=98 Area=0.127 ac Runoff=0.55 cfs 0.041 af Pond 1 P: (new node) Peak Storage=878 cf Inflow=2.36 cfs 0.179 of Primary= 1.68 cfs 0.177 af Outflow= 1.68 cfs 0.177 af Pond ecb: ecb Inflow= 1.68 cfs 0.177 af Primary= 1.68 cfs 0.177 af Runoff Area = 1.619 ac Volume = 0.179 of Average Depth = 1.33" PROPOS-2 Type III 24-hr Rainfall=2.90" Prepared by The Berkshire Design Group, Inc. Page 6 HydroCAD®6.00 s/n 000752 ©1986-2001 Applied Microcomputer Systems 2/6/03 Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Pond 1 P: (new node) Inflow = 1.54 cfs @ 12.07 hrs, Volume= 0.113 of Outflow = 1.04 cfs @ 12.16 hrs, Volume= 0.112 af, Atten= 33%, Lag= 5.4 min Primary = 1.04 cfs @ 12.16 hrs, Volume= 0.112 af Routing by Stor-Ind method, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Peak Elev= 96.06' Storage= 545 cf Plug-Flow detention time=16.8 min calculated for 0.112 af (99% of inflow) Storage and wetted areas determined by Prismatic sections Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 94.50 350 0 0 99.00 350 1,575 1,575 Primary OutFlow (Free Discharge) t1=Culvert -2=Orifice/Grate —3=Orifice/G rate —,4=Orifice/Grate # Routing Invert Outlet Devices 1 Primary 94.60' 12.0" x 33.0' long Culvert RCP, square edge headwall, Ke= 0.500 Outlet Invert= 93.80' S= 0.0242 '/' n= 0.010 Cc= 0.900 2 Device 1 96.60' 5.0" Vert. Orifice/Grate C= 0.600 3 Device 1 94.60' 6.0" Vert. Orifice/Grate C= 0.600 4 Device 1 99.00' 12.0" Horiz. Orifice/Grate Limited to weir flow C= 0.600 Pond ecb: ecb Inflow = 1.04 cfs @ 12.16 hrs, Volume= 0.112 of Primary = 1.04 cfs @ 12.16 hrs, Volume= 0.112 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind method, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs PROPOS-2 Type III 24-hr Rainfall=2.90" Prepared by The Berkshire Design Group, Inc. Page 5 HydroCAD®6.00 s/n 000752 © 1986-2001 Applied Microcomputer Systems 2/6/03 Subcatchment 1S: PAVED Runoff = 1.18 cfs @ 12.07 hrs, Volume= 0.087 af Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Type III 24-hr Rainfall=2.90" Area (ac) CN Description 0.418 98 Paved parking &sidewalks Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment b: b Runoff = 0.00 cfs @ 5.00 hrs, Volume= 0.000 af Runoff by SCS TR-20 method, UH=SCS, Time Span=5.00-20.00 hrs, dt= 0.05 hrs Type III 24-hr Rainfall=2.90" Area (ac) CN Description 0.214 39 >75% Grass cover, Good, HSG A 0.860 36 Woods, Fair, HSG A 1.074 37 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 4.5 46 0.2400 0.2 Sheet Flow, Woods: Light underbrush n= 0.400 P2=2.90" 0.3 79 0.0400 4.1 Shallow Concentrated Flow, Paved Kv= 20.3 fps 0.6 235 0.0940 6.2 Shallow Concentrated Flow, Paved Kv=20.3 fps 5.4 360 Total Subcatchment bldg: bldg Runoff = 0.36 cfs @ 12.07 hrs, Volume= 0.026 af Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Type III 24-hr Rainfall=2.90" Area (ac) CN Description 0.127 98 Paved parking & roofs PROPOS-2 Type III 24-hr Rainfall=2.90" Prepared by The Berkshire Design Group, Inc. Page 4 HydroCAD®6.00 s/n 000752 ©1986-2001 Applied Microcomputer Systems 2/6/03 Time span=5.00-20.00 hrs, dt=0.05 hrs, 301 points Runoff by SCS TR-20 method, UH=SCS, Type III 24-hr Rainfall=2.90" Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment 1S: PAVED Tc=5.0 min CN=98 Area=0.418 ac Runoff= 1.18 cfs 0.087 af Subcatchment b: b Tc=5.4 min CN=37 Area=1.074 ac Runoff=0.00 cfs 0.000 af Subcatchment bldg: bldg Tc=5.0 min CN=98 Area=0.127 ac Runoff=0.36 cfs 0.026 af Pond 1P: (new node) Peak Storage=545 cf Inflow= L54 cfs 0.113 af Primary= 1.04 cfs 0.112 of Outflow= 1.04 cfs 0.112 af Pond ecb: ecb Inflow= 1.04 cfs 0.112 af Primary= 1.04 cfs 0.112 af Runoff Area = 1.619 ac Volume =0.113 of Average Depth = 0.84" PROPOS-2 Type III 24-hr Rainfall=2.50" Prepared by The Berkshire Design Group, Inc. Page 3 HydroCADO 6.00 s/n 000752 ©1986-2001 Applied Microcomputer Systems 2/6/03 Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Pond 1 P: (new node) Inflow = 1.32 cfs @ 12.07 hrs, Volume= 0.097 of Outflow = 0.92 cfs @ 12.16 hrs, Volume= 0.095 af, Atten=30%, Lag=5.1 min Primary = 0.92 cfs @ 12.16 hrs, Volume= 0.095 of Routing by Stor-Ind method, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Peak Elev= 95.80' Storage= 455 cf Plug-Flow detention time=18.0 min calculated for 0.095 af (98% of inflow) Storage and wetted areas determined by Prismatic sections Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 94.50 350 0 0 99.00 350 1,575 1,575 Primary OutFlow (Free Discharge) t-1=Culvert 2=Orifice/Grate —3=Orifice/Grate —4=Orifice/Grate # Routing Invert Outlet Devices 1 Primary 94.60' 12.0" x 33.0' long Culvert RCP, square edge headwall, Ke=0.500 Outlet Invert= 93.80' S= 0.0242 '/' n= 0.010 Cc= 0.900 2 Device 1 96.60' 5.0" Veil. Orifice/Grate C= 0.600 3 Device 1 94.60' 6.0" Vert. Orifice/Grate C= 0.600 4 Device 1 99.00' 12.0" Horiz. Orifice/Grate Limited to weir flow C= 0.600 Pond ecb: ecb Inflow = 0.92 cfs @ 12.16 hrs, Volume= 0.095 of Primary = 0.92 cfs @ 12.16 hrs, Volume= 0.095 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind method, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs PROPOS-2 Type III 24-hr Rainfall-2.50" Prepared by The Berkshire Design Group, Inc. Page 2 HydroCAD®6.00 s/n 000752 © 1986-2001 Applied Microcomputer Systems 2/6/03 Subcatchment 1S: PAVED Runoff = 1.01 cfs @ 12.07 hrs, Volume= 0.074 af Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Type III 24-hr Rainfall=2.50" Area (ac) CN Description 0.418 98 Paved parking &sidewalks Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment b: b Runoff = 0.00 cfs @ 5.00 hrs, Volume= 0.000 af Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Type III 24-hr Rainfall=2.50" Area (ac) CN Description 0.214 39 >75% Grass cover, Good, HSG A 0.860 36 Woods, Fair, HSG A 1.074 37 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 4.5 46 0.2400 0.2 Sheet Flow, Woods: Light underbrush n= 0.400 P2=2.90" 0.3 79 0.0400 4.1 Shallow Concentrated Flow, Paved Kv=20.3 fps 0.6 235 0.0940 6.2 Shallow Concentrated Flow, Paved Kv=20.3 fps 5.4 360 Total Subcatchment bldg: bldg Runoff = 0.31 cfs @ 12.07 hrs, Volume= 0.023 af Runoff by SCS TR-20 method, UH=SCS, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs Type III 24-hr Rainfall=2.50" Area (ac) CN Description 0.127 98 Paved parking & roofs PROPOS-2 Type III 24-hr Rainfall=2.50" Prepared by The Berkshire Design Group, Inc. Page 1 HydroCAD®6.00 s/n 000752 ©1986-2001 Applied Microcomputer Systems 2/6/03 Time span=5.00-20.00 hrs, dt=0.05 hrs, 301 points Runoff by SCS TR-20 method, UH=SCS, Type III 24-hr Rainfall=2.50" Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment 1S: PAVED Tc=5.0 min CN=98 Area=0.418 ac Runoff= 1.01 cfs 0.074 af Subcatchment b: b Tc=5.4 min CN=37 Area=1.074 ac Runoff=0.00 cfs 0.000 af Subcatchment bldg: bldg Tc=5.0 min CN=98 Area=0.127 ac Runoff=0.31 cfs 0.023 af Pond 1 P: (new node) Peak Storage=455 cf Inflow= 1.32 cfs 0.097 af Primary=0.92 cfs 0.095 af Outflow=0.92 cfs 0.095 af Pond ecb: ecb Inflow=0.92 cfs 0.095 af Primary=0.92 cfs 0.095 af Runoff Area = 1.619 ac Volume =0.097 of Average Depth = 0.72" Paradise Realty Medical BuildingDrainage Report October 3, 2002(revised January 8, 2003) (revised February 6, 2003) VI. Summary The storm water management system has been designed to nearly maintain or reduce and/or are equivalent to the existing peak flow rates under proposed conditions for the 1, 2, 10, and 100 year storm frequencies. Infiltration associated with the perforated pipe surrounding the detention tank, the perforated pipe at eh toe of slope at the rear of the developed portion of the site will provide infiltration from all "clean" storm water sources. Special care has been taken treat runoff with a series of best management practices to remove total suspended solids and improve water quality to the maximum extent practicable. These practices include street sweeping, catch basins equipped with gas and oil separators and deep sumps and an integral storm water treatment chamber within the system. The proposed system outlet mimics the existing condition and prior to construction erosion control barriers will be installed as shown on the site plans. 4 Paradise Realty Medical BuildingDrainage Report October 3, 2002(revised January 8, 2003) (revised February 6, 2003) The detention structure is approximately 20'x18' with two 12" inlets as discussed above and one 12" outlet located at the bottom of the tank. Flow from the tank is discharged to a control structure where three orifices, at varying elevations and in sizes ranging from 5"-12" are used to control the discharge from the tank and maintain peak flows off the site at current levels. In addition to the control structure, a perforated pipe is proposed to be installed outside of the tank to allow flow within the tank to travel through the perforated pipe and into the surrounding gravel to ultimately provide for infiltration of some of the detained flow back into the surrounding groundwater system. Once flow is discharged from the control structure, it enters the municipal system through a new connection to the existing catch basin on Route 5/10. V. Calculations & Design Under proposed conditions runoff will be collected, treated, peak flows detained, and piped to an existing catch basin which discharges flow to an existing vegetated area located within the off ramp of exit 21 off I-91. Based on the Rational Method, the proposed changes will not significantly effect the peak flow rates. Drainage calculations for the site were performed on Hydrocad version 6.0 using SCS TR-20 methodology. The downstream control point for this site under both existing and proposed conditions was the existing catch basin on Route 5/10. Watershed subcatchment areas, runoff coefficients and watercourse slopes were based on the survey plans prepared by Harold Eaton Associates of Hadley, Massachusetts dated August 26, 2002. The proposed treatment chambers will be sized to treat the .4" storm runoff without bypass and all of this flow is detained within the detention structure. Calculations were performed for the 1, 2, 10 and 100 year frequency storms under existing and proposed conditions. Credit for infiltration provided by the perforated pipe attached to the tank was not taken. The results are shown in the summary table below. 24-hour Storm Precipitation Existing Runoff Proposed Runoff. Event (yr) (in) 1 2.5 1.02 cfs/ .075 ac-ft .92 cfs/ .095 ac-ft 2 2.9 1.19 cfs/ .087 ac-ft 1.04 cfs/ .112 ac-ft 10 4.4 1.82 cfs/ .142 ac-ft 1.68 cfs/ .177 ac-ft 100 6.4 2.67 cfs/ .247 ac-ft 2.47 cfs/ .290 ac-ft 3 Paradise Realty Medical BuildingDrainage Report October 3, 2002(revised January 8, 2003) (revised February 6, 2003) of both site entrance driveways and a single leaching catch basin located in the rear of the paved area. Currently, both trench drains are full of sand and debris and are therefore, not functional. Similarly, the leaching catch basin does not appear to be working at this time. The original drainage concept apparently utilized the single leaching catch basin located in the rear of the lot for infiltration and these two trench drains which are believed to drain to a catch basin located on Route 5/10 to remove runoff from the site. The municipal catch basin which drains the site also acts as a low point along the profile of Route 5/10, collecting a portion of this roads runoff. The existing catch basin discharges all collected runoff through an 18" RCP pipe running under Route 5/10 to an RCP flared end section located in the vegetated area of the off ramp from exit 21 off I-91. For storm water modeling purposes, the property lines at the site were used to bound the watershed with the control point located at the existing catch basin on Route 5/10. IV. Proposed Conditions The proposed condition closely mimics the existing drainage patterns, utilizing the existing catch basin in Route 5/10 as the ultimate point of discharge as well as the modeling control point. Incorporated in the proposed design are both storm water quality mechanisms as well as storm water retention and infiltration mechanisms with which to improve the quality of the runoff being discharged from the site as well as retain the peak flows off the site so as to equal the existing peak discharges from the site and to maintain groundwater recharge. Discussing the site from the rear, flow from the steep slope will be retained with a block wall equipped with a sub drain to relieve hydrostatic pressure behind the wall. This sub drain will be a 6"perforated pipe which discharges to the drainage trench located in front of the wall. The drainage trench collects both runoff from the wall sub drain as well as runoff generated by overland flow to the rear of the parking lot. All flow generated by the parking lot is put through a treatment catch basin which treats the runoff for total suspended solids and floatables utilizing stormceptor technology or an approved equal. Once treated, runoff from this catch basin is discharged into the detention chamber. In addition to the treated storm flows from the parking areas,runoff generated by the building roof is discharged directly into the detention structure. 2 Paradise Realty Medical BuildingDrainage Report October 3, 2002(revised January 8, 2003) (revised February 6, 2003) Introduction This report was originally prepared for a similar design, however, this revised report and calculations are for a reduced project. The new project consists of a smaller footprint for the building, (the original building was a single story 9,976 sf structure, the new building is a 5,625 sf two story structure), and a reduced area of pavement. This report is intended to present analysis and discussion for storm water management calculations and design performed for the Paradise Realty Groups proposed Medical Office Facility located at 766 North King Street in Northampton, Massachusetts. Construction improvements for the proposed project include: demolition of the existing building, construction of a new, 5,625 sq. foot structure intended to house medical and dental offices, reconfiguration and repaving of the existing parking lot, construction of a new parking lot, and installation of a new storm water management system and utilities. Impervious surface at the site will be increased from .42 acres to approximately .545 acres. The purpose of this analysis is to determine the 1, 2, 10 and 100 year peak flow rates for the site under current conditions and to design a storm water management system that maintains the existing peak flow rates while improving storm water runoff quality from the site. II. Site Soils According to the Natural Resources Conservation Service for the Central Part of Hampshire County (see attached soils map) the soils in the area of the proposed storm water management systems include HgA, Hinckley loamy sand, 0 to 3 percent slopes (hydrologic soil group A), Sc, Scitico silt loam (hydrologic soil group C) and Au, Amostown-Windsor silty substratum-Urban land complex (hydrologic soil group C). Type A soils were utilized for the purpose of the storm water management analysis. III. Existing Conditions The existing site houses a former vehicle service station with associated flat paved areas. Directly behind the building, the site becomes a fairly steep upward slope covered by natural forest vegetation. This condition continues to the rear property line. The existing site is shaped like a bowl where storm water runoff leaving the site flows down the steep, vegetated slopes, collecting in the flatter, service station area. Grades at the site direct runoff towards two trench drains running the length 1 - sewage disposal facilities water supply facilities B-8. Existing&proposed: landscaping,trees and plantings(size&type of plantings) stone walls, buffers and/or fencing: B-9. Signs-existing and proposed: Location dimensions/height - color and illumination B-10. Provisions for refuse removal,with facilities for screening.of refuse when appropriate: B-11. Lighting: - Location Details Photometric Plan showing no more than.5 foot candle at property line +ORM M REM 'S r . B-12. An erosion control plan and other measures taken to protect natural resources&water supplies: C. Estimated daily and peak hour vehicles trips generated by the proposed use,traffic patterns for vehicles and pedestrians showing adequate access to and from the site,and adequate vehicular and pedestrian circulation within the site. Site Plans submitted for major projects shall be prepared and stamped by a: Registered Architect, Landscape Architect,or Professional Engineer (At least one plan must have an original stamp,remaining plans must either have an original stamp or copy of original stamp.) 9 2 SITE PLAN REQUIREMENTS REQUEST FOR WAIVERS APPLICATION This form MUST be included in your application packet. The site plan MUST contain the information listed below.The Planning Board may waive the submission of any of the required information, if the Applicant submits this form with a written explanation on why a waiver would be appropriate. To request a waiver on any required information,circle the item number and fill in the reason for the request. Use additional sheets if necessary. If you are not requesting any waivers,please note that on this form. PLEASE SEE ORIGINAL SUBMISSION FOR RESPONSES TO THESE QUESTIONS A. Locus plan B. Site plan(s)at a scale of 1"--40'or greater B-1. Name and address of the owner and the developer,name of project,date and scale plans: B-2. Plan showing Location and boundaries of: the lot adjacent streets or ways all properties and owners within 300 feet all zoning districts within 300 feet B-3. Existing and proposed: -buildings -setbacks from property lines -building elevations -all exterior entrances and exits (elevation plans for all exterior facades structures are encouraged) B-4. Present&proposed use of: the land buildings: B-5. Existing and proposed topography(for intermediate projects the permit granting authority may accept generalized topography instead of requiring contour lines): at two foot contour intervals showing wetlands,streams,surface water bodies showing drainage swales and floodplains: showing unique natural land features B-6. Location of: parking&loading areas public&private ways driveways,walkways access&egress points proposed surfacing: B-7. Location and description of: all stormwater drainage/detention facilities water quality structures public&private utilities/easements 8 G. Explain how the requested use will promote City planning objectives to the extent possible and will not adversely effect those objectives,defined in City master study plans(Open Space and Recreation Plan; Northampton State Hospital Rezoning Plan;and Downtown Northampton:Today,Tomorrow and the Future). 9. I certify that the information contained herein is true and accurate to the best of my knowledge.The undersigned owner(s)grant the Planning Board permission to enter the property to review this application. The Berkshire Design Gro '►�, In. . (r-. es.ntative) 4 Allen Place Date:Date: aI(/0.3 Applicant's ant's Si g afore: , . „ , „ • •. • ��dl.�L Ii 413-582-7000 / Date: Owner's Signature: (Owners signature or letter from owner authorizing applicant to sign.) (Applicant must include waiver form on D. 8 indicating that either all information is included or that waivers are being requested.) PLEASE SEE ORIGINAL SUBMISSION FOR RESPONSES TO THE FOLLOWING QUESTIONS e r d - r� a PLEASE SEE ORIGINAL SUBMISSION FOR RESPONSES TO THE FOLLOWING QUESTIONS Does the project incorporate 3 foot sumps into the storm water control system? Yes No (IF NO, explain why) Will the project discharge stormwater into the City's storm drainage system? Yes No (IF NO,answer the following:) Do the drainage calculations submitted demonstrate that the project has been designed so that there is no increase in peak flows from pre-to post-development conditions'during the: 1, 2,or 10 year Soil Conservation Service design storm? Yes No (IF NO,explain why) Will all the runoff from a 4/10 inch rainstorm(first flush)be detained on-site for an average of 6 hours? Yes No (IF NO,explain why) Is the applicant requesting a reduction in the parking requirements? Yes No If yes,what steps have been taken to reduce the need for parking, and number of trips per day? 7 How does the project meet the special requirements?(Use additional sheets if necessary) F. State how the project meets the following technical performance standards: 1. Curb cuts are minimized: Check off all that apply to the project: use of a common driveway for access to more than one business use of an existing side street use of a looped service road 2. Does the project require more than one driveway cut? NO YES(if yes,explain why) 3. Are pedestrian,bicycle and vehicular traffic separated on-site? YES NO(if no,explain why) FOR PROJECTS THAT REQUIRE INTERMEDIATE SITE PLAN APPROVAL, ONLY.SIGN APPLICATION AND END HERE. (Applicant must include waiver form on p. 8 indicating that either all information is included or that waivers are being requested.) 9. I certify that the information contained herein is true and accurate to the best of my knowledge.The undersigned owner(s)grant Planning Board permission to enter the property to review this application. Date: Applicant's Signature: Date: Owner's Signature: (Owners signature or letter from owner authorizing applicant to sign.) .�,p a� �i; `'�°';. .a sy Y , '9yy ^., O'' t 141 •91 k,aQ ®® 9-. Q F. Explain why the requested use will: not unduly impair the integrity or character of the district or adjoining zones: not be detrimental to the health,morals or general welfare: be in harmony with the general purpose and intent of the Ordinance: 6 . B. How will the requested use promote the convenience and safety of pedestrian movement within the site and on adjacent streets? How will the project minimize traffic impacts on the streets and roads in the area? Where is the location of driveway openings in relation to traffic and adjacent streets? What features have been incorporated into the design to allow for: access by emergency vehicles: the safe and convenient arrangement of parking and loading spaces: provisions for persons with disabilities: C. How will the proposed use promote a harmonious relationship of structures and open spaces to: the natural landscape: to existing buildings: other community assets in the area: D. What measures are being taken that show the use will not overload the City's resources,including: water supply and distribution'system: sanitary sewage and storm water collection and treatment systems: fire protection,streets and schools: How will the proposed project mitigate any adverse impacts on the City's resources,as listed above? E. List the section(s)of the Zoning Ordinance that states what special regulations are required for the proposed project (flag lot,common drive,lot size averaging,etc.) 5 AMENDED SITE PLAN REVIEW AMENDED SITE PLAN REVIEW CITY OF NORTHAMPTON PLANNING BOARD APPLICATION FOR: Please Note: An omission of information could lead to a delay in processing your application. 1 ;Checkty„moo pro.ec trYi° ° , ni 'e nu It d xM :,Sltejan •� ® a °e ml wlth Sltes lan�' fir ' ' llr ®� a ®e • ® keG 'a t f? a 10 ' 1h o� r 4x ��; a. ,'C`? f _ Co.5 -6--C3 3. Applicant's Name: Paradise Realty Partners, LLC Address: 1275 Elm St. West Springfield, MA 01 =lgphone• 413-785-1153 4. Parcel Identification: Zoning Map# 8 Parcel# 21 Zoning District: HB Street Address: 766 North King St. Northampton, MA 01060 Property Recorded in the Registry of Deeds: County: Hampshire Book: 5810 Page: 273 5. Status of Applicant: Owner X ; Contract Purchaser ; Lessee ; Other • 6. Property Owner: Same as above Address: Telephone: 7. Describe Proposed Work/Project: (Use additional sheets if necessary): Demolition of existing building, construction of new 11,270 sq. ft. medical office building and associated parking, utilities and landscaping. Has the following information been included in the application? Site/Plot Plan X List of requested waivers Fee Signed Zoning Permit Review Form&Application 8. Site Plan and Special Permit Approval Criteria.(If any permit criteria does not apply,explain why) Use additional sheets if necessary. Assistance for completing this information is available through the Office of Planning&Development. A. How will the requested use protect adjoining premises against seriously detrimental uses? PLEASE SEE ORIGINAL SUBMISSION FOR RESPONSES TO THE FOLLOWING QUESTIONS. How will the project provide for: surface water drainage: sound and sight buffers: the preservation of views,light and air: 4 The Berkshire Design Group, Inc. February 6, 2003 Planning Board City of Northampton City Hall Northampton, MA 01060 RE: Amended Site Plan Approval/Special Permit for Medical Office Building. To the Planning Board: Enclosed please find the amended application for Site Plan Approval and Special Permit for the proposed medical office building at 766 North King Street. Because this is an amended site plan approval and special permit request, and as per Wayne Feiden's instructions, we have included only the project information that has changed since the original submission. Included you will find: • Application for Site Plan Special Permit • Application fee of$300.00 • Revised site plan drawings • Rendered copies of the revised building proposed for the site Landscape Architecture Civil Engineering We appreciate your review of the project, and look forward to discussing the changes with you at the earliest possible hearing date. If you have any Planning questions, or if you need any additional information, please let us know. Urban Design Sincerely, Environmental Services Th: :erkshire esign Group, Inc. Chris Wall Landscape Architect • 4 Allen Place Northampton,Massachusetts 01060 Telephone(413)582-7000 Facsimile(413) 582-7005 E-mail bdg@berkshiredesign.com City of Northampton, Massachusetts ///YYY///AAAVV*v*��� �Og ,TOE Office of Planning and Development # �� City Hall • 210 Main Street #A�._.�i 4,-1 * Northampton, MA 01060 • 41 s' ''�_-' 6.6 • {ice /�'': FAX(413) 5 7 - '26 -i I :;!,'°�'� •Community and Economic Development , ,�� • ��4•. • Conservation •Historic Preservation � f_ • Planning Board•Zoning Board of Appeals -4:1P • Northampton Parking Commission TO: Anthony Patillo, Building Inspector RE: Permit application 2 2003 1 FROM: Angela. Dion, Board Secretary/OPD DATE: -7//2 �U3 Would you please review and return the enclosed ,,v_",9( -- application before th • fanning Board oning Board of A pp eals meeting scheduled for � -k so that we can advise the Boards of any concerns you may have. I/Fa_ „k:„.„L____ Thank you.