Calculates the rate of rainwater runoff and lists appropriate Reln Surface Water Channel solution for that specific surface water drainage application.

Changing the shape or size of a channel/system can have a marked effect on the velocity of the water and how much is moved.
To estimate surface water run-off there are a number of factors that need to be considered:

  • Area of land to be serviced
  • Surface type, (impervious or pervious)
  • Type of terrain (flat, hilly or gently rolling).

Channel Capacity Calculator Disclaimer:

No warranty of any kind is expressed or implied and no liability will be accepted by Dux Industries Limited for any costs arising directly or indirectly as a result or consequences of the use of this calculator.

Channel Capacity Calculator
CALCULATE
Sending

Calculator is based on a rainfall Intensity of 100mm/hr (10 year storm)

Recommended Channel Channel Shape Flow Rate l/s
Storm Drain U Shape 0 – 9.589
Rain Drain Rectangular 0 – 10.84
Storm Mate Rectangular 0 – 4.497
Architectural Channel U Shape 0 – 8.715
Storm Masta Rectangular 10.85 – 72.92

Run off Coefficients for the Rational Method

Flat Rolling Hilly
Pavement & Roofs 0.90 0.90 0.90
Earth Shoulders 0.50 0.50 0.50
Drives & Walks 0.75 0.80 0.85
Gravel Pavement 0.85 0.85 0.85
City Business Areas 0.80 0.85 0.85
Apartment Dwelling Areas 0.50 0.60 0.70
Light Residential: 1 to 3 units/acre 0.35 0.40 0.45
Normal Residential: 3 to 6 units/acre 0.50 0.55 0.60
Dense Residential: 6 to 15 units/acre 0.70 0.75 0.80
Lawns 0.17 0.22 0.35
Grass Shoulders 0.25 0.25 0.25
Side Slopes, Earth 0.60 0.60 0.60
Side Slopes, Turf 0.30 0.30 0.30
Median Areas, Turf 0.25 0.30 0.30
Cultivated Land, Clay & Loam 0.50 0.55 0.60
Cultivated Land, Sand & Gravel 0.20 0.30 0.35
Industrial Areas, Light 0.50 0.70 0.80
Industrial Areas, Heavy 0.60 0.80 0.90
Parks & Cemeteries 0.10 0.15 0.25
Playgrounds 0.20 0.25 0.30
Woodland & Forests 0.10 0.15 0.20
Meadows & Pasture Land 0.25 0.30 0.35
Unimproved Areas 0.10 0.20 0.30

Note: Impervious surfaces in bold
Rolling = ground slope 2 – 10%
Hilly = ground slope greater than 10%

Related Products

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Rain Drain – 3m Channel & Traditional Grate
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Rain Drain – 1m Traditional Grate
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