Modeling runoff of a small design-graded yard

[RD-Design Engineer]

Dear All;

I have a container yard to design stormwater drainage facility (about 10 acre). As per the local standards - I have to calculate the runoff using the modified rational method for a 100 year storm event. The client requirements is to design a detention pond - and I have done so using manual calculations.

The engineer who will review and approve the design required to have the modeling using an analayis software.

I am currently using C3D but it does not have tools for that - it can be used to desig the grading or the pond (geometrically)

What is the available - free (or open source) best software for this task - i.e model the runoff and compute the discharge

Thank you all for your help

 

[Carla_Rohm]

Maybe look at SWMM:

https://www.epa.gov/water-research/storm-water-management-model-swmm#software and compatibility

It is opensource public software.

I am not sure whether it has the capabilities you are looking for but worth a try!

 

[Ekenny_G]

Have you looked at using HEC-HMS? its free and would get you closer to what you need.