Subject: calibration Posted: 1/29/2024 Viewed: 695 times
I'm a master student. I am using soil moisture method to allocated water resource in basin, I divided my catchment into five sub-catchment, and I have two stream gauge stations, one on the upstream which influenced by one sub-catchment, and another one in middle which influenced by two sub-catchment. I need to calibrate for streamflow at two stream gauge stations,but I have problem with model calibration..
In my area study i have a river, My question is, should I enter the headflow data in the river itself, or enough by creating catchments .
and Although I used a soil moisture method, I entered of my study area with the demand site node of agricultural and I entered the catchement without irrigation.
is it true?
Is it possible to help me? please!
Mr. Doug Chalmers
Subject: Re: calibration Posted: 2/15/2024 Viewed: 152 times
Apologies for the slow response.
Generally, users will calibrate their sub-catchments to have identical hydrology parameters. For example, you would have one value runoff resistance factor in forested land use for all catchments, and another single runoff resistance factor in grassland land use for all catchments. In addition, it is very important to setup your catchments so that their boundaries end immediately at the streamflow gauge. If you have this, then you should be able to calibrate to your gauge that is influenced by two sub-catchments, because those sub-catchments will both share identical hydrology calibration parameters.
In response to your second part. In my view, there are two fundamental ways to populate hydrology in WEAP (a combination of the two in different areas would also be possible). One method is to populate your hydrology inflows using catchment objects. This requires time and data to calibrate the hydrology parameters, but then gives you additional functionality to explore the impact of changing land use and climate on inflows. The second method is to do a direct entry, and enter the inflow data into WEAP using the headflows as you say. You either would need to have this inflow data already (perhaps from a different model), or you would have to enter historical gauge data- though you'd need to ensure that you are correctly backcalculating to consider any human impacts that take place upstream of the gauge and think about the difference between unimpaired inflows versus impaired gauge data.
Finally, you can also model irrigation demand in two fundamental ways which you identified. One is to model it using catchment with irrigation, which is able to explore the effects of changing climate on irrigation demand. The second is to enter the irrigation demand using a demand object, which does not directly tie the demands to climate or soil moisture.