Southtowns Record

PB Agenda Packet 8.13.2026

Government
Town of West Seneca
Board
Planning Board
Meeting
Aug 13, 2026, 6:00 p.m.
Posted by publisher
Jul 28, 2026
Kind
Agenda packet
Topics
Water, sewer and drainage, Roads and traffic, Housing, Zoning and land use, Parks and recreation, Budget and taxes, Public safety

Original document

Same meeting

Text · page 493 of 1174

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WEST SENECA - POST DEVELOPMENT
E_App E_Post-Development Model_REV 2  NY-West Seneca 24-hr S1 1-yr Rainfall=1.82"
Prepared by Labella Associates  Printed 7/26/2026
HydroCAD® 10.20-6a s/n 09581 © 2024 HydroCAD Software Solutions LLC  Page 26

  Summary for Pond BIO-1A: Filtration Bioretention

Inflow Area =  0.232 ac, 38.46% Impervious, Inflow Depth = 0.77" for 1-yr event
Inflow  =  0.29 cfs @ 12.04 hrs, Volume=  0.015 af
Outflow  =  0.00 cfs @ 11.29 hrs, Volume=  0.015 af, Atten= 99%, Lag= 0.0 min
Primary  =  0.00 cfs @ 11.29 hrs, Volume=  0.015 af
  Routed to Reach DP-1 : Design Point
Secondary =  0.00 cfs @ 0.00 hrs, Volume=  0.000 af
  Routed to Reach DP-1 : Design Point
Tertiary  =  0.00 cfs @ 0.00 hrs, Volume=  0.000 af
  Routed to Reach DP-1 : Design Point

Routing by Dyn-Stor-Ind method, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs
Peak Elev= 597.88' @ 21.08 hrs Surf.Area= 350 sf Storage= 454 cf
Flood Elev= 600.00' Surf.Area= 2,203 sf Storage= 3,248 cf

Plug-Flow detention time= (not calculated: outflow precedes inflow)
Center-of-Mass det. time= 1,120.1 min ( 1,965.2 - 845.1 )

Volume  Invert  Avail.Storage  Storage Description
  #1  594.42'  3,248 cf  Bioretention (Prismatic)Listed below (Recalc)

Elevation  Surf.Area  Voids  Inc.Store  Cum.Store
  (feet)  (sq-ft)  (%)  (cubic-feet)  (cubic-feet)
  594.42  350  0.0  0  0
  594.43  350  20.0  1  1
  595.25  350  20.0  57  58
  597.75  350  40.0  350  408
  598.00  350  100.0  88  496
  599.00  1,476  100.0  913  1,409
  600.00  2,203  100.0  1,840  3,248

Device  Routing  Invert  Outlet Devices
  #1  Primary  594.42'  0.500 in/hr Exfiltration Through Media over Surface area
  #2  Device 3  599.00'  24.0" x 24.0" Horiz. Overflow Grate C= 0.600
  Limited to weir flow at low heads
  #3  Secondary  594.58'  6.0" Round Culvert
  L= 25.0' CPP, projecting, no headwall, Ke= 0.900
  Inlet / Outlet Invert= 594.58' / 594.33' S= 0.0100 '/' Cc= 0.900
  n= 0.012 Corrugated PE, smooth interior, Flow Area= 0.20 sf
  #4  Tertiary  599.50'  10.0' long x 3.0' breadth Emergency Overflow Weir
  Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00
  2.50 3.00 3.50 4.00 4.50
  Coef. (English) 2.44 2.58 2.68 2.67 2.65 2.64 2.64 2.68 2.68
  2.72 2.81 2.92 2.97 3.07 3.32

  Page 493 of 1174