Approximate change in water levels in the Chicot and Evangeline aquifers 1977-88 and 1987-88, and measured compaction 1973-88, in the Houston-Galveston region, Texas [microform] / by R.K. Gabrysch, C.E. Ranzau, Jr., and L.S. Coplin ; prepared in cooperation with the city of Houston and the Harris-Galveston Coastal Subsidence District