Southtowns Record

PBA06.11.2026packet

Government
Town of West Seneca
Board
Planning Board
Meeting
Jun 11, 2026, 6:00 p.m.
Posted by publisher
Jun 3, 2026
Kind
Agenda packet
Topics
Water, sewer and drainage, Housing, Zoning and land use, Roads and traffic, Parks and recreation, Budget and taxes, Public safety

Original document

Same meeting

Text · page 558 of 849

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23-4121 storm calcs - Proposed  Type II 24-hr 100-Year Rainfall=5.23"
Prepared by Carmina Wood Design  Printed 5/14/2026
HydroCAD® 10.20-8a s/n 05019 © 2025 HydroCAD Software Solutions LLC  Page 36

  Summary for Subcatchment 3S: Direct

Runoff  =  2.52 cfs @ 11.99 hrs, Volume=  5,604 cf, Depth= 3.09"
  Routed to nonexistent node 2P

Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.50-70.02 hrs, dt= 0.04 hrs
Type II 24-hr 100-Year Rainfall=5.23"

  Area (sf)  CN  Description
  21,732  80  >75% Grass cover, Good, HSG D
  21,732  100.00% Pervious Area

  Tc Length Slope Velocity Capacity Description
  (min) (feet)  (ft/ft) (ft/sec) (cfs)
  3.4  10 0.0100  0.05  Sheet Flow,
  Grass: Dense n= 0.240 P2= 2.50"
  4.4  48 0.1200  0.18  Sheet Flow,
  Grass: Dense n= 0.240 P2= 2.50"
  7.8  58 Total

  Subcatchment 3S: Direct
  Hydrograph

  Runoff
  2.52 cfs
  Type II 24-hr
  100-Year Rainfall=5.23"
  2  Runoff Area=21,732 sf
  Runoff Volume=5,604 cf
  Flow (cfs)

  Runoff Depth=3.09"
  Flow Length=58'
  1  Tc=7.8 min
  CN=80

  0
  5  10  15  20  25  30  35  40  45  50  55  60  65  70
  Time (hours)

  Page 558 of 849