About SCS method and TR-55

[alecbcf]

I'm presently writing a study on peak discharges in the Philippines using the SCS method. Hydrologists here say, for the SCS method, they are using the storm Type II for local analysis, but then I would like to generate a local 24-hr distribution for the Philippines. My problem is this: TR-55 doesn't show a mathematical relationship of the storm type distribution curve (which may not be one of the given storm types in TR-55) to the Ia/P ratio or to the coefficients (C0, C1, C2) for the unit peak discharge (qu) formula. I'm planning to create an Excel-based program, instead of the charts provided in TR-55 to facilitate my computations. That's why I need to have a mathematical relationship. Thanks...

 

[psmart]

These are completely independent input parameters for the SCS method, hence there is no fixed relationship between them. The TR-55 tabular method probably won't help you anyway, because it is only available for specific storms. For other storms you will need to run a complete SCS unit hydrograph model, such as TR-20. Try the free HydroCAD Sampler at

http://www.hydrocad.net

and see if it solves your problems.