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 484 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 17

  Summary for Subcatchment PS-7:

Runoff  =  2.46 cfs @ 12.17 hrs, Volume=  0.212 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
  242,510  80  >75% Grass cover, Good, HSG D
  242,510  100.00% Pervious Area

  Tc Length Slope Velocity Capacity Description
  (min) (feet)  (ft/ft) (ft/sec) (cfs)
  8.5  100 0.0450  0.20  Sheet Flow,
  Grass: Short n= 0.150 P2= 2.20"
  5.3  271 0.0148  0.85  Shallow Concentrated Flow, SCF
  Short Grass Pasture Kv= 7.0 fps
  0.2  20 0.1500  1.94  Shallow Concentrated Flow, SCF
  Woodland Kv= 5.0 fps
  14.0  391 Total

  Subcatchment PS-7:
  Hydrograph

  Runoff
  2.46 cfs

  NY-West Seneca 24-hr S1 1-yr
  Rainfall=1.82"
  2  Runoff Area=242,510 sf
  Runoff Volume=0.212 af
  Runoff Depth=0.46"
  Flow (cfs)

  Flow Length=391'
  Tc=14.0 min
  1
  CN=80

  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 484 of 1174