I am attempting to calibrate a model to a series of specific rain events, the rainfall for each event is being entered by using a rainfall table following Sample “A” as found in the Hydrocad rainfall directory, and is run using the SCS hydrograph. But for output for each subcatchment area the precp. is constant for all time intervals and is the total rainfall for the entire rain event. Also the runoff is 0.0 for al time intervals. What am I missing? Is a special unit hydrograph needed?
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Calibrating model to specific rain event
- Thread starter AHSmith
- Start date
I suspect a problem with your custom rainfall table. Check the file carefully and make sure it matches the example. Also be SURE that your calculation time span is appropriate for the rainfall. If the time span starts after the rainfall is over, you won't see anything.
To test the rainfall, setup a subcat with CN=100 and Tc=0 to produce complete instant runoff. This will let you see the raw rainfall curve. Does it look the way you expect? If not, the problem is with the custom rainfall file.
The UH is another matter. In general, you can use the default SCS UH or perhaps the Delmarva UH. A custom UH is very rare.
To test the rainfall, setup a subcat with CN=100 and Tc=0 to produce complete instant runoff. This will let you see the raw rainfall curve. Does it look the way you expect? If not, the problem is with the custom rainfall file.
The UH is another matter. In general, you can use the default SCS UH or perhaps the Delmarva UH. A custom UH is very rare.
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