Subject: How to calibrate model using Mabia Method within demand sites Posted: 10/19/2016 Viewed: 1271 times
Greetings and very much thanks for your support and services in IWRM across the world......
Here is one question,
I have developed a model for whole Indus Basin irrigation System using Mabia Method. My model consists of 28 Main Canals (in Weap transmission Links) offtaking from barrages directly and 12 inter river link canals (in WEAP Diversions)covering an area of more than 15 million hectares. I run my model for 2001-2014 on daily basis and now i want to calibrate it. Which parameters I have to calibrate? kindly, let me know.
I think if when ETa is approximately equals to ETc my model will be calibrated. Is it or not? For this purpose I have to make changes in the irrigation scheduling, irrigation efficiency...
and I have to repeat this method in each crop sown in each canal command.
Kindly guide me?
Subject: Re: How to calibrate model using Mabia Method within demand sites Posted: 10/19/2016 Viewed: 1267 times
Calibrating a model means to examine a historic period and see if the model results approximate the available data for this period.
Often when we calibrate WEAP models, we calibrate for historic streamflow values from stream gauges. This means that, after entering the climate data (precip, temp) etc., and the demand data (in your case the 15 million irrigated hectares), we can compare the simulated streamflow to the historic flow at the same point in the river. Are they similar enough to suggest that model is representing the actual hydrologic system?
However, there are many other results that can be used to assist calibration. It's really a matter of what data you have. For example, do you know how much water was supplied to the different irrigation areas? You could look at that result in WEAP and see if the historic model matches the historic data. Without know what data you're using to calibrate the model, it's hard to say which parameters need to be changed.
Subject: Re: How to calibrate model using Mabia Method within demand sites Posted: 10/19/2016 Viewed: 1263 times
Actually, I have entered data sets of gauges, rivers flows data, canals flows data, climatic parameters data sets such as Precipitations, Max. and Min.Temperature, Humidity, Windspeed, Sunshine hours, etc. Cropping patterns, soil data, soil thickness etc.
Now, what you suggest?
Subject: Re: How to calibrate model using Mabia Method within demand sites Posted: 10/19/2016 Viewed: 1257 times
When you say you have entered the gauges, do you mean that you have built streamflow gauges in your model, or you have entered the historic data into the river headflow? Have you checked the flow in downstream points as well?
Subject: Re: How to calibrate model using Mabia Method within demand sites Posted: 10/19/2016 Viewed: 1252 times
Yes, i have built streamflow gauges and entered the historical flow series in the river head flows.
I think, I could not explain exactly what I am asking?.
I simply describe what I have done in my model
There are five main rivers in the system and each river has number of barrages for diversion of Main canals (here in WEAP Transmission Links) for Irrigating number of hectares of land (here in WEAP Catchments) sown by different crops. Some Excess water divertedd to ground water and return flow to rivers.
Each Barrage have stream flow gauges upstream and downstream of it.
The historical flow series of parameters are provided in each node, gauge, transmission link, catchment data sets, climatic etc etc.
Now, what to do next??
your support is very much valuable for me.
Thanks a lot once again
Subject: Re: How to calibrate model using Mabia Method within demand sites Posted: 10/23/2016 Viewed: 1207 times
kindly, Guide me how to calibrate this model. I am trying my best but could not qualify.
Subject: Re: How to calibrate model using Mabia Method within demand sites Posted: 10/24/2016 Viewed: 1199 times
Entering historical data into the rivers makes calibration a little more difficult. Where is that river flow data from? Importantly, is it from a gauge before any of the diversions in the system? If not, you might be double counting water.
Next, you have to ask yourself: what are you trying to calibrate? A calibration activity involves taking model data and comparing it to existing historical data over the same period. What historical data are you using for the calibration process? Some examples:
1) Water flow downstream of the diversions. Does the flow gauge after the diversions in the model match the historical data?
2) Demand data. Are the crops in the model demanding water that looks similar to data during the same period? You could look at flows through the transmission links.
When you clarify which data you're using for calibration, I can help guide you through the calibration process.
Subject: Re: How to calibrate model using Mabia Method within demand sites Posted: 10/25/2016 Viewed: 1193 times
Thank you for your continuous guidance.
Historical flows are observed flows at gauges installed upstream and downstream of the diversion and same like this in the model.
Secondly, I want to calibrate Demand data and wan to know that how much unmet demand is required.
Subject: Re: How to calibrate model using Mabia Method within demand sites Posted: 10/25/2016 Viewed: 1189 times
Are you looking at demand data for catchments or for demand sites? Do you have actual data to calibrate with?
I'm not sure what you mean by "how much unmet demand is required." Do you mean how much unmet demand your system has? You can look at results for unmet demand (which is Demand-Water Supplied) in Results/Demand/Unmet demand, and you call look at it for whatever your model time step is. Are you thinking to use this to calibrate? Do you have data for Demand and Water Supplied?
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