Paul Thorn

Hello,
I am creating a 3-d groundwater model looking at seawater intrusion. I am modelling an area where the aquifer is overlain by either hydrologically tight clayey till or outwash sands and gravels. Of course the type of sediments that overlie the aquifer under the sea will greatly affect the rate at which the seawater can enter into the aquifer. Therefore I would like to extend my model out into the sea.

My question - is there a way that I can designate the flow boundary-saltwater head for the model area under the sea? The only method that I can see that this is possible in the softwater (I am using Feflow 5.4) is to either use nodal, border, rubberbox in the assaign function, and using the join fuction, one can only join with either lines or supermesh, and not polygons which would cover the entire area.

If this is not possible, is there an alternative way that I can represent the constant saltwater head for the area of my model which lies under the sea?
Thank you.

I am developing a 3-D model for the freshwater-saltwater interface in an unconfined aquifer on a small island. I am able to calibrate head levels for the island, however the model has the saltwater concentrations far too high. For example, at one well, with a head of 3m, our geoelectrical soundings have shown 300mg/l chloride concentration to be at -120m, where as the model calculates that it is at a depth of -12m.

I have adjusted the boundary conditions for the head along the coastline to compensate for the density difference, as suggested in the white papers. Is there another parameter that I need to adjust in the model that I am overlooking? Any advice on how to deal with this problem is definitely appreciated.

Thanks