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 519 of 849

Read the whole document on one page (all 849 pages, each with its own heading)

23-4121 storm calcs - Existing  Type II 24-hr 25-Year Rainfall=3.84"
Prepared by Carmina Wood Design  Printed 5/14/2026
HydroCAD® 10.20-8a s/n 05019 © 2025 HydroCAD Software Solutions LLC  Page 14

  Summary for Subcatchment 2S: Existing - South

Runoff  =  4.54 cfs @ 12.13 hrs, Volume=  14,954 cf, Depth= 1.91"
  Routed to nonexistent node 6L

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 25-Year Rainfall=3.84"

  Area (sf)  CN  Description
  93,939  80  Pasture/grassland/range, Good, HSG D
  93,939  100.00% Pervious Area

  Tc Length Slope Velocity Capacity Description
  (min) (feet)  (ft/ft) (ft/sec) (cfs)
  17.5  150 0.0370  0.14  Sheet Flow,
  Grass: Dense n= 0.240 P2= 2.50"
  2.6  212 0.0370  1.35  Shallow Concentrated Flow,
  Short Grass Pasture Kv= 7.0 fps
  20.1  362 Total

  Subcatchment 2S: Existing - South
  Hydrograph

  5  Runoff
  4.54 cfs
  Type II 24-hr
  4  25-Year Rainfall=3.84"
  Runoff Area=93,939 sf
  Runoff Volume=14,954 cf
  3
  Flow (cfs)

  Runoff Depth=1.91"
  Flow Length=362'
  2
  Slope=0.0370 '/'
  Tc=20.1 min
  1  CN=80

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

  Page 519 of 849