stormcad

Question

How can we specify multiple return periods for different structures in the same design such as 25 years for some and 50 years for others and process for results?

Jesse Dringoli · Accepted Answer

One thing to note regarding Sushma's response - runoff from catchments will still propagate downstream and combine together with other flow, so a particular structure could have flow that came from a mix of storms events (if the upstream catchments used different local storm events). 
 It sounds as if you would like to look at each structure in the model individually, rather than solving it as a network? One thing you could try is the Known Flow field. This enables you to force a specific flow through a pipe, overriding any upstream flows. This would normally be used in cases where you have measured flows, but you might be able to use it to force different return events through each structure, if you are able to determine the appropriate flow for each return event.

Sushma Choure · Answer

Hello Steve, 
 You can select one return event which will be assigned to majority of catchments as global storm event and for other storm event e.g. 25 years you can apply locally to the catchments. You can select local storm event for a single catchment or if there are multiple then you can make a selection set of those elements and then apply to that selection. 
 This is has been explained with the help of an example in the link mentioned below, please go through it. 
 Modeling multiple storm events in a single scenario