Tarsier Tutorial: Adding GroundWater to Watershed Simulation

This tutorial provides instructions on how to how a groundwater component to you Watershed Simulation Model.

Prerequisites

Open your Marmoset form with all appropriate data (eg Net Data, Precipitation Series, Model Time, Landscape Parameters...)
For your convenience you can save your Watershed form in the Watershed Usee control
Open and save your watershed analysis form with these data: Hydro DEM, Net Ptr, Stream raster and Tarsier Network Data (tne)
Open Aquifer Tab in Watershed Analysis tool
Click Calc Floodplain
- Warning: Must have your Net Ptr, HydroDEM, and Stream Raster open in their usee controls.
- This tool creates a raster covering your floodplain according to your set max flood height
- Default max flood height it 1 meter. This should be estimated and changed to suit your watershed.
Click Calc Floodplain Area
- Warning: Must have your Net Ptr, HydroDEM, and Stream Raster And your floodplain raster open in their usee controls.
- This too breaks up your floodplain and connects a floodplain area with a corresponding node.
Click Calc Aquifer From Floodplain
- Warning, must have your floodplain raster open, and have calculated floodplain area
- This tool uses a hillslope parameter to estimate triangular aquifer geometry
- The default hillslope is 15 degrees from horizontal, make a good estimation for your watershed.
- Warning, a hillslope less then or equal to zero, or greater or equal to ninety will not work properly.

Go to "Watershed models" tab
In the "Watershed model type" group, there is an option to use the groundwater model, when you are ready check that box to include ground water
There are a number of ground water parameters grouped at the bottom of the page
- The Percolation parameter is the percentage of surface water that will infiltrate into the shallow subsurface storage
- The Slope Factor gives the steeper channels of the river a smaller tendency to percolate water. Set this to 1 for a homogeneous percolation rate.
- Darcy's K is a coefficient of subsurface lateral flow. A value of zero will result in no lateral subsurface flow. The higher the value the faster water will flow.
- Near Surface Storage Depth is the space available for percolation from the surface water in a given time step.
- Aquifer Porosity is the space available for water in the aquifer. (eg A value of 0.5 means that of the entire aquifer, 50% is occupied by material and the rest is available for water)
- Max ET is the maximum amount of subsurface evapotranspiration that will occur. Right now this value of ET is set for the Surface.
- ET Extinction Depth is how far down evapotranspiration will take place under the surface. The ET in between the surface and the extinction depth banishes linearly with depth.
- The Aq Perc Rate is the rate at which water will leave the shallow storage and enter the aquifer, this is confusingly percent per time step. Also, 0.5 = %50 etc...