I am creating a model for an area where the water table is very high - I tried using unsaturated settings but when I thought i was done calibrating the model in steady state and introduced a well, the heads in the well and the nodes around became negative (in the order of -1000). I then tried using the saturated setting and constraining the maximum elevation to the top slice, this seems to work, but then themodel becomes insensitive to all my other parameters! What is the best approach for this type of conditions?