Dear Members
Is it possible to consider reservoir loss to GW as a function of reservoir elevation?

> Dear Members
Can reservoir elevation be taken into account when analyzing reservoir loss to GW?

How do I specify the groundwater node in the local reservoir water supply system?

Majid and Mohammed,

Yes, to model reservoir loss to groundwater as a function of reservoir elevation, go in the data tree to your reservoir and go to Physical (in the top right expression tab) --> Loss to Groundwater, and then you can either use the Expression Builder or the Lookup Wizard (click on the arrow in the expression box to get there) to reference the Storage Elevation value of the reservoir. Note that it is based off the storage in the previous timestep- you could also think of this as the starting storage elevation in the current timestep. This is because WEAP has not yet solved for the ending storage elevation in the current timestep.

You could alternatively get creative with the expressions and predict the storage elevation change in the current timestep based on supply and demand inputs in the current timestep if the above does not work for you.

Finally, to specify the groundwater node that the reservoir losses drain to, click on "to Groundwater" immediately to the left of the Loss to Groundwater expression entry mentioned above.

Hope this helps!
-Doug