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 185 of 1174

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E_App E_Post-Development Model  NY-West Seneca 24-hr S1 1-yr Rainfall=1.82"
Prepared by Labella Associates  Printed 4/20/2026
HydroCAD® 10.20-7a s/n 09581 © 2025 HydroCAD Software Solutions LLC  Page 13

  Summary for Subcatchment PS-8:

Runoff  =  0.40 cfs @ 12.36 hrs, Volume=  0.047 af, Depth= 0.46"
  Routed to Reach DP-1 : Design Point

Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-72.00 hrs, dt= 0.01 hrs
NY-West Seneca 24-hr S1 1-yr Rainfall=1.82"

  Area (sf)  CN  Description
  53,474  80  >75% Grass cover, Good, HSG D
  53,474  100.00% Pervious Area

  Tc Length Slope Velocity Capacity Description
  (min) (feet)  (ft/ft) (ft/sec) (cfs)
  15.6  100 0.0100  0.11  Sheet Flow, SF
  Grass: Short n= 0.150 P2= 2.20"
  8.8  371 0.0100  0.70  Shallow Concentrated Flow, SCF
  Short Grass Pasture Kv= 7.0 fps
  1.3  350 0.0100  4.54 3.56 Pipe Channel, Pipe Flow
  12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25'
  n= 0.013 Corrugated PE, smooth interior
  25.7  821 Total

  Subcatchment PS-8:
  Hydrograph

  0.44  Runoff
  0.42
  0.40 cfs
  0.4  NY-West Seneca 24-hr S1 1-yr
  0.38
  0.36  Rainfall=1.82"
  0.34  Runoff Area=53,474 sf
  0.32
  0.3  Runoff Volume=0.047 af
  0.28  Runoff Depth=0.46"
  0.26
  Flow (cfs)

  0.24  Flow Length=821'
  0.22  Slope=0.0100 '/'
  0.2
  0.18  Tc=25.7 min
  0.16  CN=80
  0.14
  0.12
  0.1
  0.08
  0.06
  0.04
  0.02
  0
  0 2  4 6  8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72
  Time (hours)

  Page 185 of 1174