Reference Document - Flood & Stormwater Management Plan 28_8_2025

33 Pavilion St
23-0167

L Gillis
04/10/2023
ARR2016

 

RATIONAL METHOD SUMMARY & RAINFALL DATA

10
15
20
25
30
45
60.00
90.00
120.00
180.00
270.00
360.00
540.00
720.00
1080.00
1440.00
1800.00
2160.00
2880.00
4320.00

1 1.0075669| 0.6553598 | 0.22487336 | -0.113584 | 0.0190669 | -0.001362 | 3.423E-05
2 1.1258065 | 0.6506015| 0.2318719 | -0.117139 | 0.0198273 | -0.001428 | 3.616E-05
5 1.424489 | 0.6620312| 0.222184 | -0.115032 | 0.0197897 | -0.001441 | 3.667E-05
10 1.5850968 | 0.6825591| 0.20021482 | -0.10711 | 0.0185666| -0.001353 | 3.418E-05
20 5% | 1.7200166] 0.7080383| 0.17219149 | -0.096592 | 0.0168551 | -0.001224 | 3.048E-05
50 2% | 1.8736345] 0.7649483| 0.10527054 | -0.068783 | 0.0116344| -0.000762| 1.48E-05
100 1% 1.976603 | 0.8128499 | 0.048541624| -0.044997 | 0.0071252| -0.000359 | 1.091E-06

 

Catchment Data

 

 

 

 

Details: Variable | Value Units

Exisiting Scenario - SUB3 Area: 1.78 ha
fi 0.21 fraction
Cio 0.55 fraction

 

 

 

 

 

Rational Method Summary:

Overland flow time (min) 20.60
Pipe flow time (min)

Adopted Time of Concentration (tc) (min) 20.6
Duration (hours) 0.3

Freq Factor 0.80 0.85 1.05 1.15 1.20
Duration (hours) 20.60 20.60 20.60 20.60 20.60

Duration (min) 0.34 0.34 0.34 0.34 0.34
Intensity (mm/hr) 70.15 78.92 142.26 165.46 183.04
Discharge (m*/s) 0.1536 | 0.1837 0.4089 0.5209 | 0.6013

 

Document Set ID: 24092538
Version: 1, Version Date: 02/09/2025