I have field observed data on water table which is varying daily. We are interested in developing a HYDRUS 2D model, which can predict moisture content in soil profile above water table. Is it okay to create a domain with depth equal to water table and assign CONSTANT HEAD boundary condition ( value as 0 m) to represent water table?
A constant pressure head BC could be used if you want to model an existing groundwater level that is constant, i.e., that doesn't change with time.
For a varying water table you might want to look at using a variable pressure head BC (if you know the change in water table from your field data). The groundwater level can then be specified in the "Time Variable Boundary Conditions" window using the "Var.H-1" column for variable head and then choosing "Variable Flux 1" as lower BC (ditto for Var.H-2, Var.H-3, or Var.H-4). That is what I would try for your application, since you know the varying water levels in the soil.
A deep drainage BC in HYDRUS approximates a flux through the boundary depending on the position of the water table (higher water table means larger flux), but that would be calculated by HYDRUS and you would need to specify some modeling parameters (see HYDRUS help for more information on those).
With precipitation and etp as model input data, but optimized the flow of high water and flooding to determine annual maximum daily rainfall to see the trend of rainfall and the generated flow rates. Determine the return periods of these maxima
Thanks Jan, I will try the steps.
Will the domain depth (which I specify) play any role the process which you mentioned.
For example, water table ranges from 1.4 to 1.8 m in the field. Can I specify my domain depth as 2 meter?
If yes, will the model predict the domain below specified (Variable Head 1) water table depth as saturated.
Thanks Amoussou for answering the question.
I am unable to understand your explanation (I am new to HYDRUS, may be I am not that advanced).
Can you please elaborate, how to optimize the water flow.
Thanks Amoussou for answering the question.
I am unable to understand your explanation (I am new to HYDRUS, may be I am not that advanced).
Can you please elaborate, how to optimize the water flow.
Thanks Ahmed.
Are you suggesting to specify WATER CONTENT as my initial condition ?
if you have recorded the varying water table level, you should use the condition of variable pressure head.
You can use variable pressure head and this can be allowed to vary in space as well using the boundary condition options if there is a gradient. If the variation is not large you could also try the deep drainage option. Trying both these boundary conditions will allow you to see how much detail you need.
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