Subject: Ground water information Posted: 11/13/2015 Viewed: 6069 times
If I have a ground water resource and and I don't give the WEAP any information about it like the recharge or maximum withdraw ....etc, Is not the WEAP suppose it is (Ground water information) infinity and use this GW as a resource to supply the demand sites.
Because in my case I dont have any infomation about the ground water and the WEAP is not using the GW as a scource until I input it is values.
Subject: Re: Ground water information Posted: 11/13/2015 Viewed: 6064 times
The capacity of the groundwater is considered unlimited if there is no data, but you must enter information about the Initial Storage. If your groundwater exists in the Current Accounts year, you can enter it there (it will be under the Physical button), otherwise, if your groundwater is in a scenario, you will enter it in the scenario after you've specified the Startup Year.
Think of groundwater as a glass of water. Perhaps we don't know how big the glass is (the Storage Capacity), but we need to know how much water is currently there (or currently accessible) if we are going to model it over time. There is an exercise in the WEAP tutorial that demonstrates the use of groundwater - in the Refining the Supply module, Modeling Groundwater Resources.
Subject: Re: Ground water information Posted: 11/15/2015 Viewed: 6009 times
Thank you so much. This was really helpful.
Subject: Re: Ground water information Posted: 11/16/2015 Viewed: 5961 times
Do you know any model or method that we can estimate initial storage of groundwater from streamflow data?
Subject: Re: Ground water information Posted: 11/17/2015 Viewed: 5953 times
How I wish that were an easy answer!
I think you'd have to a general water balance for your whole system using historic data, and then a calibration against the streamflow data. You could do that in WEAP, or it can be done in Excel as (for example) an "abc" model, or and "abcd" model. You can read about both here:http://engineering.tufts.edu/cee/people/vogel/documents/parsimonious-watershed-chap22.pdf.
But those techniques require calibrating all sorts of parameters - I'm not convinced it's better than entering the data in WEAP and considering the initial groundwater storage for your model as one of your calibration parameters. So that's what I'll recommend - plug in something reasonable, and then when you're looking at your modeled streamflow compared to your recorded streamflow for your system, see what difference it makes to change the initial groundwater storage value.
Also, remember that WEAP defaults to "specify groundwater-surface water flows" - which means that there won't be any interaction between groundwater and rivers unless you connect them with links. You can change this to "model groundwater-surface water flows (groundwater/physical/method) and then enter regions of interaction with the river. See the Hydrology module in the WEAP tutorial for more information.