Southtowns Record

5A.-ENGINEER'S REPORT

Government
Town of Aurora
Board
Town Board
Meeting
Feb 4, 2026
Kind
Other
Topics
Water, sewer and drainage, Zoning and land use, Public safety

Original document

Same meeting

Text · page 195 of 351

Read the whole document on one page (all 351 pages, each with its own heading)

WNY-2500056.00_HydroCAD  extreme_precip_tables_output (29) 24-hr S1 10-yr Rainfall=3.14"
Prepared by Greenman-Pedersen, Inc  Printed 12/18/2025
HydroCAD® 10.20-7a s/n 04560 © 2025 HydroCAD Software Solutions LLC  Page 120

  Summary for Pond SWALE: SWALE

Inflow Area =  0.280 ac, 64.29% Impervious, Inflow Depth > 2.28" for 10-yr event
Inflow  =  0.64 cfs @ 12.02 hrs, Volume=  0.053 af
Outflow  =  0.37 cfs @ 12.31 hrs, Volume=  0.042 af, Atten= 43%, Lag= 17.4 min
Primary  =  0.37 cfs @ 12.31 hrs, Volume=  0.042 af
  Routed to Pond RCVR 1 : RCVR 1

Routing by Dyn-Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs
Peak Elev= 901.23' @ 12.30 hrs Surf.Area= 1,197 sf Storage= 972 cf

Plug-Flow detention time= 145.5 min calculated for 0.042 af (79% of inflow)
Center-of-Mass det. time= 69.4 min ( 858.9 - 789.6 )

Volume  Invert  Avail.Storage  Storage Description
  #1  900.00'  2,104 cf  Custom Stage Data (Prismatic) Listed below (Recalc)

Elevation  Surf.Area  Inc.Store  Cum.Store
  (feet)  (sq-ft)  (cubic-feet)  (cubic-feet)
  900.00  396  0  0
  901.00  1,038  717  717
  902.00  1,736  1,387  2,104

Device  Routing  Invert  Outlet Devices
  #1  Primary  900.68'  8.0" Round 8" HDPE L= 32.0' CPP, mitered to conform to fill, Ke= 0.700
  Inlet / Outlet Invert= 900.68' / 900.55' S= 0.0041 '/' Cc= 0.900
  n= 0.013 Corrugated PE, smooth interior, Flow Area= 0.35 sf

Primary OutFlow Max=0.38 cfs @ 12.31 hrs HW=901.23' TW=901.09' (Dynamic Tailwater)
  1=8" HDPE (Outlet Controls 0.38 cfs @ 1.67 fps)