Removal of water, oil, and gas from the subsurface in Harris and Galveston Counties, Texas, has caused a decline in fluid pressures, which is turn had resulted in subsidence of the land surface. Subsidence of the land surface at Seabrook is due principally to the removal of water. Significnt subsidence of the land surface probably began after 1920, and a minimum of about 3.3 feet and a maximum of about 4.3 feet of subsidence had occurred at Seabrook by 1973.
Probable future subsidence was calculated by two different methods for each of two different loading situations. In the first loading situation, the artesian heads in the Alta Loma Sand (Rose, 1943) and Evangeline aquifer would continue to decline at the respective rates of 8 feet per year and 7 feet per year until 1980 and then cease. In the second loading situation, the artesian heads in the Alta Loma Sand and Evangeline aquifer would continue to decline at rates of 8 and 7 feet per year ulntil 1990 and then cease.