The current ASTER DEM production software has a water detection option. The default option is "water = on," but users may select "water = off."
The default option generally produces satisfactory results. However, anomalous results have been noted with water detection "on for certain scenes that contain dark objects other than water, such as shadows or black rocks, particularly for scenes at high altitude, which exhibit substantial topographic relief. For such scenes, users may wish to select "water = off." If your final DEM product is visually suspect, please contact the User Services to explore further options.