Subject: Calibration Posted: 11/12/2021 Viewed: 5126 times
Dear Friends,
Hope you are all well.
I have problems related to Calibration and Validation. I am not using climate data to drive a hydrological model (mean's I have no Climate and Land use Land Cover (LULC) data to simulate the main rivers head flow). I have flows data u/s and d/s of the barrages (a structure just use to raise the level of water,short-duration storage, and to divert the river water into the manmade channel (canal). Actually, in Pakistan water is diverted into the main irrigation canal by not considering the CWD (crop water demand) but on the availability of water that means in Pakistan supply-based system is adopted rather than demand-based. On the other hand in WEAP When I model the canal as a diversion. As I know, Diversion pulls water as much as it is needed. The question is how I can calibrate my model in this situation?
Description About my Model and Data: I have daily flows data on the u/s and d/s of the Barrages and Canal head flows data. Climate Data (Mean Monthly Precipitation data, Maximum and Minimum temperature data, Relative Humidity data, Sunshine hours data, and Wind Speed data for the Canal command area (CCA) the area over which canal irrigation water flows by gravity. I model my demand site as an Agriculture catchment by using the irrigation demand only method. I am stuck on the calibration process for many months. I will be highly thankful if anyone could help me.
Ms. Anne Hereford
Subject: Re: Calibration Posted: 11/23/2021 Viewed: 5089 times
Dear Nalain,
I'm not sure i understand your model constraints well. Could you put a Flow Requirement on the diversion? You could set up an expression to make the Flow Requirement depend upon the flow of the river.
Anne
Mr. Nalain E Muhammad
Subject: Re: Calibration Posted: 4/10/2022 Viewed: 4530 times
Dear Anne Hereford
Thanks For your Reply, How could I set up an expression to make the flow requirement depend upon the flow of the river.
Ms. Anne Hereford
Subject: Re: Calibration Posted: 4/11/2022 Viewed: 4524 times
You'll create a Flow Requirement node in the proper place on your schematic. Then, in the Data view, find the flow requirement (under Supply and Resources/River). In the expression box (for Current Accounts or for a particular Scenario if you want to enter the Flow Requirement by Scenario), you'll enter something like the following:
If(PrevTSValue(Supply and Resources\River\NEM River\Reaches\Below NEM River Headflow:Streamflow[m^3]) >=3,2,1)
This says if the previous time step Streamflow in the first segment of the river (Headflow) is greater than or equal to 3, the flow requirement is 2. And if it's less than 3, the requirement is 1.
For more about writing expressions in WEAP, see the Expressions Overview section of the help.
Anne
Mr. Nalain E Muhammad
Subject: Re: Calibration Posted: 5/11/2022 Viewed: 4321 times
Basically, My next question is to ask about the approach that I adopted to calibrate the model. whether am I correct or wrong? If I am wrong please correct me. I put the Flow requirement node on the diversion as you said and add upstream discharge data of flow rate(cumec) headwork on the river head flow and downstream discharge data on the stream gauge node which I placed on the d/s of the headwork.
Your reply will be helpful for me. This question is very important for me to complete my master thesis project.
Ms. Anne Hereford
Subject: Re: Calibration Posted: 6/22/2022 Viewed: 4116 times
Generally speaking, streamflow is an important component when calibrating a model, and it is common to compare stream gauge data to your model's discharge data at the corresponding location when evaluating the calibration.
So yes, you are on the right track by comparing historical gauge data to your model output flow. It will be up to you to decide how closely these numbers need to match in order to have a model that is calibrated sufficiently for your needs.
Mr. Nalain E Muhammad
Subject: Re: Calibration Posted: 6/23/2022 Viewed: 4107 times
Thanks for your reply
But I am not comparing historical gauge data with model output flow.
As I mentioned, Basically I am not using climate data to drive a hydrological model (which means I have no Climate and Land use Land Cover (LULC) data to simulate the main rivers head flow). I have just added data as input in the river head flow and put a stream gauge node on the d/s of the river headworks. (used to control the flow rate at the d/s of the structure and man-made channels for irrigation).
Mam kindly replies as soon as possible.
Mr. Nalain E Muhammad
Subject: Re: Calibration Posted: 6/23/2022 Viewed: 4100 times
Mam, I think I could not clarify you properly.
I am doing the Calibration process by just adding data on rivers head flow as input (not models output flow) and secondly adding data on stream gauge node which I placed d/s of the barrage and flow requirement node on the canal (model as a diversion) that carries water towards the agriculture field. I basically want to calibrate the model by the water balance approach. Could be calibrated in this way?
