calculate depth of sinks

Discussion created by saiorse on Nov 29, 2010
I'm working on volume calculation on certain surfaces with arcGIS 9.3. All Files are in point shape file format with xyz coordinates.
So far I interpolated the point shp file onto a grid and filled it with the 'Fill' Tool. The difference is the volume.
For further investigation I would like to know the depth of certain sinks on the surface/grid. How can I calculate the distance between water surface and the surface of the sink? I need to know the deepest point of each sink.
Can somebody help me out?
kind regards,