I have created a Surface Elev Tin, and a Groundwater Elev. TIN. I want to be able to get a difference between the two. So the Surface elevation is 6ft and the GWE is 2 ft. Somewhere I want it to tell me that the depth to groundwater is 4'. I'd like to do this at any given point in the surface tin. I can identify on a point in the TIN and the results display, but I need to flag areas that are <2 feet to groundwater from the surface. Either in a Depth to Groundwater tin, or another surface. thanks for the suggestions.