Subject: calibration problem - Urgent need Posted: 11/12/2015 Viewed: 18881 times
Hello,
I would like to use WEAP to model the water allocation planing in one of the watershed here as part of my thesis. I'm calibrating the model in 4 streamgauges and I'm surprised to see no flow in the catchment inflow node of my river while the streamgage have flow.
Anyone could suggest me what to do ? Please ?
Thank you
Ms. Stephanie Galaitsi
Subject: Re: calibration problem - Urgent need Posted: 11/12/2015 Viewed: 18869 times
Dear Malak,
I don't know what data you've entered into your river, but the data in the streamflow gauges don't interact with the model - they are there for comparison purposes. If you don't have flow in your river, you probably have not given it a source of water, either by entering the headflow data in the river itself, or by creating catchments. Then you can compared the modeled data to your historic streamflow gauge data to calibrate the model.
Miss MALAK ALAMI
Subject: Re: calibration problem - Urgent need Posted: 11/16/2015 Viewed: 18807 times
Dear Stephanie,
Thank you very much. Everything looks fine now. But some reservoirs in my models looks empty and they do not contain any water.
Why that's hapenning ? Please advice.
Ms. Stephanie Galaitsi
Subject: Re: calibration problem - Urgent need Posted: 11/16/2015 Viewed: 18791 times
Dear Malak,
The reservoirs have a default demand priority of 99. If there are any other demands in the system (such as a city, agricultural site, or instream flow requirement), those had a default demand priority of 1.
This means that the reservoir(s) will only fill when all demands downstream are met: they cannot withhold water from demand sites with higher demand priorities. If your system has more demand than supply downstream of the reservoir, the reservoir will never retain water. Instead it will pass it downstream so the other demand sites can meet their demand.
You can look at this in 2 ways in the results section. Navigate to Demand/Unmet Demand, and see if your downstream demand sites have deficits, and when. This is when the reservoir will not retain water. You can also look at Supply and Resources/Reservoir/Storage Volume, to see if (and when) the reservoirs are getting water. If there are no periods of complete coverage for your downstream demand sites, there are probably no periods when your reservoir is getting supply. Alternatively, maybe it is storing some water, and then giving it away immediately to meet the demands downstream. Let me know if that is that case, and if you don't want that.
Miss MALAK ALAMI
Subject: Re: calibration problem - Urgent need Posted: 11/17/2015 Viewed: 18747 times
Dear Stephanie,
Thank you very much.
Please help me -- I have two reservoirs in my model application and they should be filled every year and satisfye demand (mainly irrigation and Drinking water).
The first one is filled every year except in drought years. It delivers water to demand sites but it still retain water while There is high unmet demand in these irrigated perimeters.
The second one, the storage is equal to 0 in all years while it should deliver water to two irrigated perimeters. There is high unmet demand there.
There is something wrong. Maybe the reservoir is not receiving much water for deliveration but this should be the case only for drought years. Also, when I run reference scenario for the 2030 horizon, the volume is 0.
So I'm not sure where the problem comes from.
Thank you !
Malak
Ms. Stephanie Galaitsi
Subject: Re: calibration problem - Urgent need Posted: 11/17/2015 Viewed: 18740 times
Dear Malak,
Is your irrigation downstream of the reservoir? What is its demand priority?
If there is unmet demand downstream, the reservoir will not retain any water. It will let the demand site take the water. Reservoirs are effective in situations where there is too much water sometimes (for example, in the winter) and not enough water at other times (like the summer). Reservoirs can collect water during the wet times to release them during the dry times. However, if your agriculture demands water all year and there is always insufficient water, there is never a good time for the reservoir to collect water.
Have you entered "Monthly variation" information for your agriculture sites? There's a good example of this in the WEAP tutorial (in the first exercise, WEAP in One Hour). That way you can make sure that your annual patterns of agricultural demand reflect the temporal demands in the system.
Ms. Stephanie Galaitsi
Subject: Re: calibration problem - Urgent need Posted: 11/17/2015 Viewed: 18732 times
Dear Malak,
Is your irrigation downstream of the reservoir? What is its demand priority?
In the absence of other constraints***(see below), if there is unmet demand downstream, the reservoir will not retain any water. It will let the demand site take the water. Reservoirs are effective in situations where there is too much water sometimes (for example, in the winter) and not enough water at other times (like the summer). Reservoirs can collect water during the wet times to release them during the dry times. However, if your agriculture site demands water all year and there is always insufficient water, there is never a good time for the reservoir to collect water.
Have you entered "Monthly variation" information for your agriculture sites? There's a good example of this in the WEAP tutorial (in the first exercise, WEAP in One Hour). That way you can make sure that your annual patterns of agricultural demand reflect the temporal demands in the system.
***Other constraints that can hinder the reservoir from releasing water: There are several constraints you add in WEAP that would affect the behavior of the reservoir. Here are some examples:
1) Transmission to the demand sites is limited: if you constrain your transmission link, the reservoir will only release as much water as can be supplied in the transmission link, rather than the total quantity of demand.
2) You have entered information about an inactive zone in your reservoir. That water, by definition, cannot be accessed.
3) You have entered information about a buffer zone in your reservoir, which might limit how much can be released in a single timestep.
4) You have entered information the reservoirs maximum hydraulic outflow.
Ms. Meghna Dave
Subject: Re: calibration problem - Urgent need Posted: 7/3/2018 Viewed: 10251 times
Hi Malak,
I am currently using WEAP to calibrate a reservoir which has 2 inflows and 2 outflows. The reservoir is actually a lake, and the data I have entered into WEAP includes the total storage capacity, the initial storage capacity, the volume elevation curve, net evaporation and observed volume. However, when I run my resuls, the simulated storage volume just represents the total storage capacity of the reservoir. Slight fluctuations are noted when I make changes to the loss to groundwater.
Is there a way to ensure that the computed reservoir volume is a function of the inflows to and outflows from the lake?
Thanks and regards,
Meghna
Mr. Jack Sieber
Subject: Re: calibration problem - Urgent need Posted: 7/5/2018 Viewed: 10248 times
Hi Meghna,
I do not think there is a problem with the mass balance on your reservoir -- Inflow minus Outflows equals Change in Storage. If your reservoir is always full, my guess is that the inflows are too large. If the inflows are from catchment runoff, you need to calibrate the catchment.
