Subject: Effective Precipitation Posted: 7/15/2014 Viewed: 22447 times
Hello,
I would like to ask a question relating about effective precipitation data for the catchments. In WEAP, we need to put that data for the effective rainfall in percentage form and WEAP's definition for effective rainfall is the percentage of rainfall available for evapotranspiration.
But I understood for effective rainfall is the percentage of rainfall available for runoff. So, I want to confirm that it is right or not if I put 0% for the case effective rainfall and actual rainfall are the same.
The % that you enter for the parameter Effective Precipitation of a catchment object is the % available for evapotranspiration, the rest being direct runoff.
Examples:
* if you enter 80% (if you are in a sort of arid environment for example), then up to 80% of the rainfall can become evapotranspiration (depending on ETRef and Kc) with the remaining 20% running off to the river (to create river flow - these 20% will transit from the catchment object to the river through the Runoff/Infiltration link that WEAP creates automatically between the catchment object and the river),
* if you enter 30% (if you are in a rather humid environment), then up to 30% of the rainfall can evapotranspirate and 70% becomes runoff.
