Land-surface subsidence in the Houston - Galveston region, Texas.

The pumping of large amounts of ground water in the Houston - Galveston region, Texas, has resulted in water-level declines of as much as 200 feet (61 meters) in wells completed in the Chicot aquifer and as much as 325 feet (99 meters) in wells completed in the Evangeline aquifer during 1943-73. The maximum average annual rates of decline for 1943-73 were 6.7 feet (2.0 meters) in the Chicot aquifer and 10.8 feet (3.3 meters) in the Evangeline aquifer. During 1964-73, the maximum rates were 10 feet (3.0 meters) in the Chicot and 17.8 feet (5.4 meters) in the Evangeline. The declines in artesian pressures have resulted in pronounced regional subsidence of the land surface.