Hello,

I would like to know what is the meaning of head flow in WEAP? I have some data; stream flow, temperature and rainfall for 5 stations along the main river. I haven't the separate head flow data for main river. How can I get the head flow for the main river?

Thank you

Hi Myat,

When you draw a river in WEAP, it has a place where it starts and head flow in WEAP is the value of the flow in the first reach of the modeled river. Natural rivers trickle into existence in elevated areas, so "headflow" would be hard to measure in real life.

The streamflow data you have is not headflow, it is flow in downstream sections of the river. If you have a gauge that is very high up in the watershed, and you are only modeling downstream flow there, you could theoretically use that data as your WEAP river's headflow - but only for a historic model, since you don't have that gauge data in the future.

It sounds like you would like to calculate the headflow for the model using temperature and precipitation data, and then calibrate (verify that you have calculated the streamflow correctly) using the five gauging stations downstream. You can use the Soil Moisture Method hydrological model to do this (one of the catchment methods). See the Hydrology chapter of the WEAP tutorial, available at www.WEAP21.org/tutorial

Hi Ms. Stephanie Galaitsi,

Thank you for your help. Kindly, I have the inflow data to Nasser Lake in Egypt, can I consider this data as headflow? additionally, every modelling area must have headflow data?
Thank you