In ArcGIS 10.1 (advanced license) I have a bare-earth DEM (5m cell size) and I would like to identify depressions which at least, say, 4 meters below the surrounding ground.
What I have tried is to use Focal Statistic to produce a smoothed DEM representing the average elevation within a given moving window, and then subtracting that from the original DEM in order to spot negative areas (=depressions). The problem is that the smoothed DEM so obtained is biased toward high elevations, since (needless to say) them mean is "pulled" toward high elevation values. Therefore, I got not conclusive results.
Edit: I found a solution myself, and I will post the answers in case someone will jump here in the future.