Documentation of a computer program to simulate aquifer-system compaction using the modular finite-difference ground-water flow model

This report presents a computer program for simulating aquifer-system compaction resulting from ground-water storage changes in compressible beds. A formal release of this report will be available in the future as a chapter in Techniques of Water-Resources Investigations of the U.S. Geological Survey. The program documented in this report is designed for incorporation into the modular finite-difference ground-water flow model developed by the U.S. Geological Survey. The performance of this computer program has been tested in models of both hypothetical and actual ground-water flow systems. Future applications, however, may reveal errors that were not detected in the test simulations. Prior to the formal release of this report, users are requested to notify the originating office of any errors found in the report or in the computer program. Updates may occasionally be made to both the report and computer program.