Subject: Water balancing in ground water Posted: 8/13/2014 Viewed: 20200 times
Hello,
I have a question about Ground water supply source. In my model, I need to put GW source but I have not enough data, so I used the simplest way and I simulated my model.
But WEAP is just balancing the outflow and inflow of the GW source.
My idea is I want to show the ground water table is lowering (the initial storage is decreasing) because of monthly withdrawal, however, WEAP is running without using the initial storage, just only using the inflow.
If there is not enough inflow, outflow for demand is zero.
The result is showing like that.
So, I would like to know how I can do and what input command I have to give to balance the water from the whole source.
Thanks a lot for ur help.
Zaw
Dr. Devaraj de Condappa
Subject: Re: Water balancing in ground water Posted: 8/18/2014 Viewed: 20119 times
Dear Zaw,
I am not sure it would solve you problem but just some questions below:
* to describe groundwater you are using the groundwater object (green square)?
* when you edit the data for this object, in the tab Method, do you have 'Specify GW-SW flows'?
* you have entered a value for the tab 'Initial Storage' in Million m3?
* have you entered a value for the 'Natural Recharge' (which I suppose is the Inflow you are referring about)? Or are you simulating the recharge with infiltration from a catchment object?
* when you compare the value of 'Initial Storage' with 'Natural Recharge' (or the inflow from your catchment object) and the value of the Water Demand connected to the groundwater object, all are in the same order of magnitude? (check the unit). For example, would you have the 'Initial Storage' much smaller than the 'Natural Recharge' (or the inflow from your catchment object) and also much smaller than the Water Demand withdrawing water from the Groundwater Object? If yes then the behaviour you are observing is normal and I would presume you have an error of magnitude (I would expect that you would have 'Initial Storage' > Water Demand > 'Natural Recharge' (or the inflow from your catchment object) so that you have a slowly depetion of the GW storage as you would like to simulate).
