Figure A-2-Magnitude of the subsidence problem in southern Louisiana. Backstripping of 6 km of sediments (column A) requires about 2.7 km of change in water depth (column B). Using a reasonable estimate of 200 m change in water depth still leaves 1.4 km of unaccounted excess subsidence (column C) that could be balanced by 400 m of excess thermal subsidence and 4 km of salt withdrawal (column D).