A customer wanted us to conduct an analysis of water run-off in the region. Originally they wanted us to super-impose their sketches on top of the digital cadastre and the contours. But I came up with a better idea. I grabbed the DEM tiles for the geographic extent. Transformed it into a 3D Surface in ArcMap. Then used contrasting colour symbology to display the change in elevation, based on the pixel height value.
Water generally flows from high to low. So now you can clearly see where the water run-off is going. :)