Hello
I am setting up MIKE SHE for a catchment in Cape Town. The catchment has very flat low lying sandy areas where a primary aquifer exists and is "pinched out" towards mountains that exist in the upper reaches of the catchment. The topography increases in elevation from sea level to over 1000m above sea level over a 10km distance. The increase in elevation is a result of a rugged mountain range that forms part of Table mountain.
The issue arises where I have used bedrock point measurements to specify the Lower level of the aquifer, which occur mainly in the low lying area. When MIKE SHE interpolates these values, the bedrock is well below the soil surface for most of the catchment. However this is not the case as the bedrock forms a mountain range in the upper reaches of the catchment.
My question is: Is there any appropriate way to model this situation? Is it possible to use 3D Finite difference modelling for just the lower areas and a lumped goundwater model for the upper parts of the catchment, because the sand aquifer effectively gets "pinched out" towards the upper parts of the catchment?
Or would it be more appropriate to add additional points to the bedrock layer that indicate the bedrock and topography are at the same height in the upper reaches? However this may prove too much for interpolation techniques which have to interpolate bedrock that is changes so rapidly...
Thank you for the help.
Regards
Ben
