Calculating Peak Q's

[ponderosa]

I am performing a HEC-RAS analysis where I am using flows for the 10, 50, & 100 year events from an old FEMA study. I also need the 2 & 25 year Q's though. Does anyone know of a way to estimate them from the known Q's? Besides using a standard method (ie SCS, Regional) to recalculate them.

 

[Bayou]

You can plot the known frequencies/ flows on a probability graph. From the graph, the 2 & 25 year flows can be interpolated.