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All Topics | Topic "Absence of Rivers: Only a groundwater source"
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Author Message
Ms. Anuradha Maharaj

Subject: Absence of Rivers: Only a groundwater source   
Posted: 3/5/2015 Viewed: 17615 times
I have a model where we only have Groundwater as a source of water supply. There are no rivers. GW is being recharged by 30% of the precipitation. it is assumed that 30% is lost to evapotranspiration and 40% is lost to runoff. We are unsure of where these percentages will be input in WEAP.
For the GW recharge, we used 30% of the monthly rainfall data. Then, under the 'runoff and infiltration' tree, we have loss from precipitation to groundwater source = 30% also. We would like to know if this is right because when we run our model we get " Catchment runoff fraction s must sum to 100%. In this case, the sum is 30%"...how do we rectify this?

When we run our model,in the results pane for "Land class inflows and outflows", the precipitation is equal to groundwater. Nothing has been deducted as withdrawal.

Thanks in Advance.
Dr. Devaraj de Condappa

Subject: Re: Absence of Rivers: Only a groundwater source   
Posted: 4/8/2015 Viewed: 17380 times
Dear Anuradha,

Apologise for late reply.

I presume you are not doing any hydrological modelling in WEAP but just want to set that groundwater recharge = 30% of the precipitation.

If this is the case, then you have to do as follows:

1. You have to add a groundwater object in the schematic (green square) and NOT the catchment object (green dot). Then when you right click on this object in the schematic, select Edit Date > Natual Recharge. There you enter that the recharge = 30% of the precipitation. (you can use the ReadFromFile function to read a file where you would have stored the precipitation data).

2. By only adding the groundwater object and NOT the catchment object, you won't see the 'runoff and infiltration' tree, so you should not enter anything for 'runoff and infiltration'.

3. If you don't want to follow the flow in the river, you don't need to do anything more. But if you want, then add a river object. Then right click on the river and select 'Headflow'. There you can enter that the runoff is 40% of precipitation.

4. You don't bother about the 30% lost by evapotranspiration as this is lost.

I hope it answers your question.

Kind regards,

Ms. Anuradha Maharaj

Subject: Re: Absence of Rivers: Only a groundwater source   
Posted: 4/14/2015 Viewed: 17339 times
Dear Devaraj,

I am grateful for the reply and the detailed explanation!

Much appreciated!

Best regards,
Topic "Absence of Rivers: Only a groundwater source"