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 518 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 13

  Summary for Subcatchment 1S: Existing - North

Runoff  =  7.12 cfs @ 12.23 hrs, Volume=  28,850 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
  131,812  80  Pasture/grassland/range, Good, HSG D
  49,422  79  Woods/grass comb., Good, HSG D
  181,234  80  Weighted Average
  181,234  100.00% Pervious Area

  Tc Length Slope Velocity Capacity Description
  (min) (feet)  (ft/ft) (ft/sec) (cfs)
  16.9  150 0.0400  0.15  Sheet Flow,
  Grass: Dense n= 0.240 P2= 2.50"
  5.2  287 0.0170  0.91  Shallow Concentrated Flow,
  Short Grass Pasture Kv= 7.0 fps
  4.0  284 0.0280  1.17  Shallow Concentrated Flow,
  Short Grass Pasture Kv= 7.0 fps
  2.1  85 0.0180  0.67  Shallow Concentrated Flow,
  Woodland Kv= 5.0 fps
  28.2  806 Total

  Subcatchment 1S: Existing - North
  Hydrograph

  Runoff
  7.12 cfs
  7  Type II 24-hr
  25-Year Rainfall=3.84"
  6
  Runoff Area=181,234 sf
  5  Runoff Volume=28,850 cf
  Flow (cfs)

  Runoff Depth=1.91"
  4
  Flow Length=806'
  3  Tc=28.2 min
  CN=80
  2

  1

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

  Page 518 of 849