This amount of time can be calculated with the Time Of Concentration Calculator.
The analysis is the same as the Time Area Diagram method with the time area diagram being built with an even spread of the area over the time of concentration.
Eg. Time of Concentration = 3 mins, Area = 0.75ha
If the timestep is 1 minute, A1 = 0.25, A2 = 0.25, A3 = 0.25.
The rainfall profile and the time area diagram are combined with the volumetric runoff coefficient in the following way:
Q1 = (I1 x A1) x 2.78 x Cv
Q2 = (I1 x A2 + I2 x A1) x 2.78 x Cv
Q3 = (I1 x A3 + I2 x A2 + I3 x A1) x 2.78 x Cv
And so on…
|Scroll pdf ignore|
Workflow - What's next...?
Connections Inflows to your Time of Concentration, specify Inlets or Outlets Outlets Outlets or connect to another Stormwater Control or JunctionsInflows connect to either Junctions or Stormwater controls via Inlets. Specify an Outlet on these objects then choose to connect to another Junction or Stormwater Control.