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 556 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 34

  Summary for Subcatchment 2S: Proposed - South

[47] Hint: Peak is 1092% of capacity of segment #3
[47] Hint: Peak is 293% of capacity of segment #4
[47] Hint: Peak is 250% of capacity of segment #5

Runoff  =  9.33 cfs @ 12.12 hrs, Volume=  31,254 cf, Depth= 3.99"
  Routed to Pond 1P : Detention Pond

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
  22,791  98  Roofs, HSG D
  22,002  98  Paved parking, HSG D
*  1,626  98  Concrete, HSG D
  47,520  80  >75% Grass cover, Good, HSG D
  93,939  89  Weighted Average
  47,520  50.59% Pervious Area
  46,419  49.41% Impervious Area

  Tc Length Slope Velocity Capacity Description
  (min) (feet)  (ft/ft) (ft/sec) (cfs)
  1.4  10 0.0900  0.12  Sheet Flow,
  Grass: Dense n= 0.240 P2= 2.50"
  15.6  43 0.0040  0.05  Sheet Flow,
  Grass: Dense n= 0.240 P2= 2.50"
  1.3  194 0.0050  2.45 0.85 Pipe Channel, 8" @ 0.5%
  8.0" Round Area= 0.3 sf Perim= 2.1' r= 0.17'
  n= 0.013 Corrugated PE, smooth interior
  0.9  209 0.0080  4.06 3.19 Pipe Channel, 12" @ 0.8%
  12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25'
  n= 0.013 Corrugated PE, smooth interior
  0.6  171 0.0110  4.76 3.74 Pipe Channel, 12" @ 1.1%
  12.0" Round Area= 0.8 sf Perim= 3.1' r= 0.25'
  n= 0.013 Corrugated PE, smooth interior
  19.8  627 Total

  Page 556 of 849