Hello WEAP users
I know that Runoff Resistance Factor related to Leaf Area Index - LAI and Slope. In my catchment, I have data about LAI and Slope, how to calculate Runoff Resistance Factor from them.
Thanks all !

Hi Pham,

I'm going to link you to another thread in the WEAP forum: http://www.weap21.org/index.asp?action=9&read=1952&fID=30. Does this help?

Yes. Thank you Stephanie
I already read it before. But it still not really help me.

But I could not find the answer in the link. Stephanie can you pl help me to calculate the RRF.

Dear Sujit,

The runoff resistance factor is not a calculated value, it is a parameter in an equation that helps to determine surface runoff (see the Soil Moisture Method section in the Help Menu for equations of the Soil Moisture Method). You, as the user, must adjust the values of the RRF so that your runoff produces a quantity of water consistent with your historic flow record. The RRF contributes only to the surface/direct runoff, and the streamflow is a sum of this flow plus interflow and base flow.