Loading...
Stormwater ReportHutchins Engineering PLLC STORMWATER MANAGEMENT SUMMARY Proposed residence for Julie and Mark Prendeville 102 Ash Drive Queensbury NY Parcel ID # 289.13-1-58 169 Haviland Road Queensbury, NY 12804 Phone: (518) 745-0307 Fax: (518) 745-0308 The applicants propose to remove the existing residence and construct a new residence on their property located at 102 Ash Drive, Queensbury, NY. Stormwater for all newly created impervious areas in managed by infiltration devices constructed on the site. All new house rooftop runoff will be collected in eave gutters and routed to a 4'x4' precast concrete drywell in a stone. Runoff from newly created gravel drives and parking areas is routed to infiltration trenches adjacent to the drive areas. For residential projects, the Town of Queensbury requires that calculated stormwater runoff rate and volume not exceed pre -project levels for the 25-year model storm. Calculations have been prepared using HydroCAD modelling software and are attached. Calculations are summarized as follows: Z5-YEAR CALCULATED STQRMWATER RUNOFF SUMMARY EXISTING PROPOSED DESIGN POINT AREA RATE CFS VOLUME (CF) RATE CFS VOLUME (CF) DP1-TO GLEN LAKE 12,143 SF 0.13 427 0.0 71 DP2 - SOUTHERLY 9,894 SF 0.0 61 0.0 57 DP3-ENTIRE SITE 22,037 SF 0.13 488 0.0 129 Calculated runoff rates indicated as 0.0 CFS indicate runoff rate less than 0.005 CFS. Attached are subcatchment maps and HydroCAD model reports of the 25-year storm event for both the existing and proposed conditions. EXISTING CONDITIONS SUBCATCHMENT MAP HYDROCAD MODEL REPORT 1 13er+rif�oSt Bur Lane fP''fyarey 1 heewr �4i�Wae y °B7 3 F 1 toy 356 IpWI IS u rm S 622 —3StE ' 7•�t��`� � � � J 32.2 8 AT MENT 2/ L 28'(>A ' IPI,d94 rTOTALL p 03°58'55 21. 630 5F FEOG f�5F`0# S , Sheer / H Hr 1 •.Lire sy° N4a Zd Gz�ng W 6°°k U P NM] i B:3675 P:1 289.13-1-54 o< I I EXISTING NEIGHBORING RESIDENCE F Q. AREA STWATER MODEL = 22,037 SF f N�Adjoining Hou e - 77�� W_ 14' !r,82. P Ut4ty. M Jo, 1 q' O6' E p' , Aq 314 Oock 6• n. ur S ad J_Jq 5 t. r a' She spur: � �` .w� 24• White t`r �.r� k } ` ,� sm MENT 1� 1 12.43 5f TOTAL I 11, 60 5F P:RVI0I5 4275F rk - BREVE ' [ r 4 G9 5P - SHED l 72 5r - WALKSa myµ _ Pq. �`vw.tire •r.�o.+,� � �.er r.044o +r � � • ". m. ` w w �w a c IV 8=s� w ' mod Frame (, Haub@ N ' 3 White! 4' n° 4'± To Shore Glen Lake IL I Lands N/F of 36'Tw.O�ty /ice/ �4'± To Shore Patrick A. & Sally H. Russo B:904 P:148 289.13-1-59 EXISTING OUSE AND LOWER SITE DP1 GLEN LAKE 3L TOTAL SITE Sub4 (Reach on L ink 2S EXISTINC31 UPPER AREA AND DRIVE DP2 )UTHERLY PRENDEVILLE - EXISTING Prepared by Hutchins Engineering Printed 10/28/2022 H droCAD® 9.10 s/n 02373 © 2010 H droCAD Software Solutions LLC Page 2 Area Listing (all nodes) Area CN Description (sq-ft) (su bcatch ment-n u m bers) 16,790 32 Woods/grass comb., Good, HSG A (1S, 2S) 3,573 76 Gravel roads, HSG A (1S, 2S) 1,602 98 Roofs, HSG A (1S, 2S) 72 98 Unconnected pavement, HSG A (1 S) 22,037 TOTAL AREA PRENDEVILLE - EXISTING Type/1 24-hr 25-YR Rainfall=4.40" Prepared by Hutchins Engineering Printed 10/28/2022 H droCAD® 9.10 s/n 02373 © 2010 H droCAD Software Solutions LLC Page 3 Summary for Subcatchment 1S: EXISTING HOUSE AND LOWER SITE Runoff = 0.13 cfs @ 12.00 hrs, Volume= 427 cf, Depth= 0.42" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-26.00 hrs, dt= 0.05 hrs Type II 24-hr 25-YR Rainfall=4.40" Area (sf) CN Description 8,160 32 Woods/grass comb., Good, HSG A 1,484 98 Roofs, HSG A 72 98 Unconnected pavement, HSG A 2,427 76 Gravel roads, HSG A 12,143 49 Weighted Average 10,587 87.19% Pervious Area 1,556 12.81% Impervious Area 72 4.63% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) ft/ft) (ft/sec) (cfs) 3.6 20 0.1000 0.09 Sheet Flow, SHEET FLOW Woods: Light underbrush n= 0.400 P2= 2.40" 1.2 350 0.1000 4.74 Shallow Concentrated Flow, SHALLOW CONCENTRATED FL01 Grassed Waterwav Kv= 15.0 fps 4.8 370 Total Summary for Subcatchment 2S: EXISTING UPPER AREA AND DRIVE Runoff = 0.00 cfs @ 15.19 hrs, Volume= 61 cf, Depth= 0.07" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-26.00 hrs, dt= 0.05 hrs Type II 24-hr 25-YR Rainfall=4.40" Area (sf) CN Description 8,630 32 Woods/grass comb., Good, HSG A 118 98 Roofs, HSG A 1,146 76 Gravel roads, HSG A 9,894 38 Weighted Average 9,776 98.81% Pervious Area 118 1.19% Impervious Area Tc Length Slope Velocity Capacity Description min feet ft/ft) ft/sec cfs 3.6 20 0.1000 0.09 Sheet Flow, SHEET FLOW Woods: Light underbrush n= 0.400 P2= 2.40" 0.4 100 0.1000 4.74 Shallow Concentrated Flow, SHALLOW CONCENTRATED FL01 Grassed Waterwav Kv= 15.0 fps 4.0 120 Total PRENDEVILLE - EXISTING Type/1 24-hr 25-YR Rainfall=4.40" Prepared by Hutchins Engineering Printed 10/28/2022 HvdroCAD® 9.10 s/n 02373 © 2010 H droCAD Software Solutions LLC Page 4 Summary for Link 3L: TOTAL SITE Inflow Area = 22,037 sf, 7.60% Impervious, Inflow Depth = 0.27" for 25-YR event Inflow = 0.13 cfs @ 12.00 hrs, Volume= 488 cf Primary = 0.13 cfs @ 12.00 hrs, Volume= 488 cf, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-26.00 hrs, dt= 0.05 hrs Summary for Link 13131: GLEN LAKE Inflow Area = 12,143 sf, 12.81% Impervious, Inflow Depth = 0.42" for 25-YR event Inflow = 0.13 cfs @ 12.00 hrs, Volume= 427 cf Primary = 0.13 cfs @ 12.00 hrs, Volume= 427 cf, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-26.00 hrs, dt= 0.05 hrs Summary for Link DP2: SOUTHERLY Inflow Area = 9,894 sf, 1.19% Impervious, Inflow Depth = 0.07" for 25-YR event Inflow = 0.00 cfs @ 15.19 hrs, Volume= 61 cf Primary = 0.00 cfs @ 15.19 hrs, Volume= 61 cf, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-26.00 hrs, dt= 0.05 hrs PROPOSED CONDITIONS SUBCATCHMENT MAP HYDROCAD MODEL REPORT I j I B:3675 P:1 B9l1l8DSt BOP Lar1e �pl'Iy ° 1 J alal r _ 289.13-1-54 I .. o• rmr. r.. .ar p/, a Itirr�rr k'•rw � J fpv Y r rmr ! 1 r+s "LIG EXISTING 1 £ � NEIGHBORING aTrw 3 on S 62* r � E RESIDENCE 7- 5Y ,, % ` 32.2 I. � �' r � 5UBCJ1 �IIIT 4 9.3 X TOTAL Ta O.k , 1 ' ii JJ A a 3 PERVIO * 03°58'55 �, AREA OF STORMWATER MODEL = 2Zo37 SF �( I' '2/167.rSQ. FA r,la1s1,-MVF z I --- O. 112 , - es 1 18 5F - 5itED 21. (/ She + '� c•>a+orr e!eyrr�''�•r , Adjoining e xau d � TAN c �/ 'Xsr J� i7'�Lk gyp\ ar oC l o. yom ray 14•"+.v - 5:-8Z Y4.06 30.6' 314 F 1 O 34 sr 10iRi V shed flack p .rw 1 �r J� 1 8r soak sera 4'± TO Shore r .O' F P'AMVWA145 - A7i4M1A1wn �`� za• vents r.e i 3NED 6 ,$ 5 � L �_ao•❑ � rrr p ov sTCWENT TCFil4T ��.SF TO IVE Glen Lake =o „gibpmvv DP 1 W PROK a YIiV'I TFEVCH SfWVW 0R1 V.C. NM 141 PARKNIG � w _` SERVNVG NEW �sr � x w� B , BE AFROVED 1ROM SERNNG PARKM -- 7 1O5 424 DOS 4 ai • n k warm 1' 3'rf r �r5 -� Lands N/F of 36'rr Oak 4'± To Shore \ Patrick A. & Sally H. Russo 8:904 P:148 \ '�� �- Q 289.13-1.59 2S EXIST. DRIVE AND 1S NEW P RKING LOWER VA 77 AREA NT �P (i) NEW H SE ROOF NEW DRI E AREA INFILT TION 3P THE CH RYWELL DP1 GLEN LAKE SuE�cat Reaoi� vn Link 4S FINISHED UPPER AREA AND DRIVE NEW 6 PPER PARKING GRAVEL 5P INFILTRATION TRENCH [DP2 , SOUTHERLY /f F f 3L TOTAL SITE PRENDEVILLE - PROPOSED Prepared by Hutchins Engineering Printed 10/28/2022 H droCAD® 9.10 s/n 02373 © 2010 H droCAD Software Solutions LLC Page 2 Area Listing (all nodes) Area CN Description (sq-ft) (su bcatch ment-n u m bers) 15,568 32 Woods/grass comb., Good, HSG A (1S, 4S) 1,141 76 Gravel roads, HSG A (4S) 396 98 DECK (1S) 2,009 98 GRAVEL DRIVE/PARKING (2S) 591 98 GRAVEL PARKING AREA (5S) 1,294 98 Roofs, HSG A (3S, 4S) 17 98 SHED ROOF (1S) 1,020 98 Unconnected pavement, HSG A (1S) 22,036 TOTAL AREA PRENDEVILLE - PROPOSED Type // 24-hr 25-YR Rainfall=4.40" Prepared by Hutchins Engineering Printed 10/28/2022 HydroCAD® 9.10 s/n 02373 ©2010 HydroCAD Software Solutions LLC Page 3 Summary for Subcatchment 1S: LOWER VACANT AREA Runoff = 0.00 cfs @ 15.11 hrs, Volume= 71 cf, Depth= 0.10" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-26.00 hrs, dt= 0.05 hrs Type II 24-hr 25-YR Rainfall=4.40" Area (sf) CN Description 7,525 32 Woods/grass comb., Good, HSG A 396 98 DECK 1,020 98 Unconnected pavement, HSG A 17 98 SHED ROOF 8,958 43 Weighted Average, UI Adjusted CN = 39 7,525 84.00% Pervious Area 1,433 16.00% Impervious Area 1,020 71.18% Unconnected Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 17.2 100 0.0500 0.10 Sheet Flow, SHEET FLOW Woods: Light underbrush n= 0.400 P2= 2.40" 5.2 350 0.0500 1.12 Shallow Concentrated Flow, SHALLOW CONCENTRATED Woodland Kv= 5.0 fps 22.4 450 Total Summary for Subcatchment 2S: EXIST. DRIVE AND NEW PARKING Runoff = 0.29 cfs @ 11.95 hrs, Volume= 697 cf, Depth= 4.16" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-26.00 hrs, dt= 0.05 hrs Type II 24-hr 25-YR Rainfall=4.40" Area (sf) CN Description 2,009 98 GRAVEL DRIVE/PARKING 2,009 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Summary for Subcatchment 3S: NEW HOUSE ROOF Runoff = 0.17 cfs @ 11.95 hrs, Volume= 408 cf, Depth= 4.16" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-26.00 hrs, dt= 0.05 hrs Type 11 24-hr 25-YR Rainfall=4.40" PRENDEVILLE - PROPOSED Type 11 24-hr 25-YR Rainfall=4.40" Prepared by Hutchins Engineering Printed 10/28/2022 H droCADO 9.10 s/n 02373 © 2010 H droCAD Software Solutions LLC Page 4 Area (so CN Description 1,176 98 Roofs, HSG A 1,176 100.00% Impervious Area Tc Length Slope Velocity Capacity Description min (feet) ft/ftft/sec cfs 5.0 Direct Entry, Summary for Subcatchment 4S: FINISHED UPPER AREA AND DRIVE Runoff = 0.00 cfs @ 15.19 hrs, Volume= 57 cf, Depth= 0.07" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-26.00 hrs, dt= 0.05 hrs Type II 24-hr 25-YR Rainfall=4.40" Area (sf) CN Description 8,043 32 Woods/grass comb., Good, HSG A 118 98 Roofs, HSG A 1,141 76 Gravel roads, HSG A 9,302 38 Weighted Average 9,184 98.73% Pervious Area 118 1.27% Impervious Area Tc Length Slope Velocity Capacity Description min feet ft/ft ft/sec cfs 3.6 20 0.1000 0.09 Sheet Flow, SHEET FLOW Woods: Light underbrush n= 0.400 P2= 2.40" 0.4 100 0.1000 4.74 Shallow Concentrated Flow, SHALLOW CONCENTRATED FLO1 Grassed Waterwav Kv= 15.0 fps 4.0 120 Total Summary for Subcatchment 5S: NEW UPPER PARKING GRAVEL Runoff = 0.09 cfs @ 11.95 hrs, Volume= 205 cf, Depth= 4.16" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-26.00 hrs, dt= 0.05 hrs Type II 24-hr 25-YR Rainfall=4.40" Areas CN Description 591 98 GRAVEL PARKING AREA 591 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) ft/ft(ft/sec) (cfs) 5.0 Direct Entry, PRENDEVILLE - PROPOSED Type 11 24-hr 25-YR Rainfall=4.40" Prepared by Hutchins Engineering Printed 10/28/2022 HydroCAD® 9.10 s/n 02373 © 2010 HydroCAD Software Solutions LLC Page 5 Summary for Pond 2P: NEW DRIVE AREA INFILTRATION TRENCH Inflow Area = 2,009 sf,100.00% Impervious, Inflow Depth = 4.16" for 25-YR event Inflow = 0.29 cfs @ 11.95 hrs, Volume= 697 cf Outflow = 0.03 cfs @ 11.60 hrs, Volume= 697 cf, Atten= 89%, Lag= 0.0 min Discarded = 0.03 cfs @ 11.60 hrs, Volume= 697 cf Primary = 0.00 cfs @ 0.00 hrs, Volume= 0 cf Routing by Stor-Ind method, Time Span= 0.00-26.00 hrs, dt= 0.05 hrs Peak Elev= 412.98' @ 12.26 hrs Surf.Area= 140 sf Storage= 223 cf Plug -Flow detention time= 39.3 min calculated for 696 cf (100% of inflow) Center -of -Mass det. time= 39.2 min ( 784.4 - 745.2 ) Volume Invert Avail.Stora a Storage Description #1 409.00' 224 cf 2.00'W x 70.00'L x 4.00'H Prismatoid 560 cf Overall x 40.0% Voids Device Routina Invert Outlet Devices #1 Discarded 409.00' 10.000 in/hr Exfiltration over Horizontal area #2 Primary 413.00' 30.0' long x 1.0' breadth Broad -Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 Coef. (English) 2.69 2.72 2.75 2.85 2.98 3.08 3.20 3.28 3.31 3.30 3.31 3.32 Discarded OutFlow Max=0.03 cfs @ 11.60 hrs HW=409.04' (Free Discharge) t-1=Exfiltration (Exfiltration Controls 0.03 cfs) Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=409.00' (Free Discharge) t-2=Broad-Crested Rectangular Weir ( Controls 0.00 cfs) Summary for Pond 3P: DRYWELL Inflow Area = 1,176 sf,100.00% Impervious, Inflow Depth = 4.16" for 25-YR event Inflow = 0.17 cfs @ 11.95 hrs, Volume= 408 cf Outflow = 0.03 cfs @ 12.12 hrs, Volume= 408 cf, Atten= 80%, Lag= 10.1 min Discarded = 0.03 cfs @ 12.12 hrs, Volume= 408 cf Primary = 0.00 cfs @ 0.00 hrs, Volume= 0 cf Routing by Stor-Ind method, Time Span= 0.00-26.00 hrs, dt= 0.05 hrs Peak Elev= 410.06' @ 12.12 hrs Surf.Area= 147 sf Storage= 137 cf Plug -Flow detention time= 34.0 min calculated for 407 cf (100% of inflow) Center -of -Mass det. time= 34.0 min ( 779.2 - 745.2 ) PRENDEVILLE - PROPOSED Type 11 24-hr 25-YR Rainfall=4.40" Prepared by Hutchins Engineering Printed 10/28/2022 H droCADO 9.10 s/n 02373 © 2010 H droCAD Software Solutions LLC Page 6 Volume Invert Avail.Storage Storage Description #1 406.00' 159 cf 4.00'W x 4.00'L x 5.00'H DRYWELL STONE Z=1.0 447 cf Overall - 50 cf Embedded = 396 cf x 40.0% Voids #2 407.00' 50 cf 4.00'D x 4.00'H DRYWELL Inside #1 209 cf Total Available Storage Device Routinq Invert Outlet Devices #1 Discarded 406.00' 10.000 in/hr Exfiltration over Horizontal area #2 Primary 412.00' 2.0' long x 1.0' breadth Broad -Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 Coef. (English) 2.69 2.72 2.75 2.85 2.98 3.08 3.20 3.28 3.31 3.30 3.31 3.32 Discarded OutFlow Max=0.03 cfs @ 12.12 hrs HW=410.05' (Free Discharge) L7=Exfi1tration (Exfiltration Controls 0.03 cfs) Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=406.00' (Free Discharge) L2=113road-Crested Rectangular Weir ( Controls 0.00 cfs) Summary for Pond 5P: INFILTRATION TRENCH Inflow Area = 591 sf,100.00% Impervious, Inflow Depth = 4.16" for 25-YR event Inflow = 0.09 cfs @ 11.95 hrs, Volume= 205 cf Outflow = 0.01 cfs @ 11.65 hrs, Volume= 205 cf, Atten= 85%, Lag= 0.0 min Discarded = 0.01 cfs @ 11.65 hrs, Volume= 205 cf Primary = 0.00 cfs @ 0.00 hrs, Volume= 0 cf Routing by Stor-Ind method, Time Span= 0.00-26.00 hrs, dt= 0.05 hrs Peak Elev= 423.61' @ 12.16 hrs Surf.Area= 56 sf Storage= 58 cf Plug -Flow detention time= (not calculated: outflow precedes inflow) Center -of -Mass det. time= 23.2 min ( 768.5 - 745.2 ) Volume Invert Avail.Stora a Storage Description #1 421.00' 67 cf 2.00'W x 28.00'L x 3.00'H Prismatoid 168 cf Overall x 40.0% Voids Device Routinq Invert Outlet Devices #1 Discarded 421.00' 10.000 in/hr Exfiltration over Horizontal area #2 Primary 424.00' 4.0' long x 1.0' breadth Broad -Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 Coef. (English) 2.69 2.72 2.75 2.85 2.98 3.08 3.20 3.28 3.31 3.30 3.31 3.32 Discarded OutFlow Max=0.01 cfs @ 11.65 hrs HW=421.05' (Free Discharge) 't-1=Exfiltration (Exfiltration Controls 0.01 cfs) Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=421.00' (Free Discharge) 't-2=B road -Crested Rectangular Weir ( Controls 0.00 cfs) PRENDEVILLE - PROPOSED Type // 24-hr 25-YR Rainfall=4.40" Prepared by Hutchins Engineering Printed 10/28/2022 HvdroCAD® 9.10 s/n 02373 ©2010 H droCAD Software Solutions LLC Page 7 Summary for Link 3L: TOTAL SITE Inflow Area = 22,036 sf, 24.17% Impervious, Inflow Depth = 0.07" for 25-YR event Inflow = 0.00 cfs @ 15.15 hrs, Volume= 129 cf Primary = 0.00 cfs @ 15.15 hrs, Volume= 129 cf, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-26.00 hrs, dt= 0.05 hrs Summary for Link DP1: GLEN LAKE Inflow Area = 12,143 sf, 38.03% Impervious, Inflow Depth = 0.07" for 25-YR event Inflow = 0.00 cfs @ 15.11 hrs, Volume= 71 cf Primary = 0.00 cfs @ 15.11 hrs, Volume= 71 cf, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-26.00 hrs, dt= 0.05 hrs Summary for Link DP2: SOUTHERLY Inflow Area = 9,893 sf, 7.17% Impervious, Inflow Depth = 0.07" for 25-YR event Inflow = 0.00 cfs @ 15.19 hrs, Volume= 57 cf Primary = 0.00 cfs @ 15.19 hrs, Volume= 57 cf, Atten= 0%, Lag= 0.0 min Primary outflow = Inflow, Time Span= 0.00-26.00 hrs, dt= 0.05 hrs