"It is useful to know the depth of a sink or group of sinks. This information can be used to determine an appropriate z-limit for the Fill function"
"The tool iterates until all sinks within the specified z limit are filled"
"The Fill tool fills sinks to remove imperfections from the DEM. A Z-limit affects the
result of the tool. It is recommended to state the Z-limit if the depths of the sinks are known. The Sink (Spatial Analyst) tool canbe used to identify the sinks and their depths prior to using the Fill tool.
When a Z-limit is not specified in the Fill tool window, all sinks, regardless of depth, are filled."
My depths range from ~0 to 25... How does that information correspond to the z limit... do i set it to it's max of 25, or a % or just try random numbers? Any information is appreciated