The Book of Texas Bays

8. Galveston Island

71 Houston is a town filled with geologists.The main reason, of course, is the oil business. Many of them expend their professional attention on using modern technology to find hydrocarbon deposits. Others of a more academic turn of mind, like my friend H. C. Clark concern themselves with geologic processes and with how human settlements and the earth’s geology coexist. H.C., fondly referred to by me as “the Doctor,” is a professor emeritus in the geology department at Rice University, where he and I first met. Over the years, the Doctor and my law partner Mary Carter and I have been involved in numerous cases in which law and geology came together. H.C. has been my mentor in geology for almost three decades, though I still struggle with some of the concepts. When a geologist starts talking about geologic time, for instance, prepare yourself to slow down quite a bit. Fifty or a hundred years are nothing, and even thousand-year spans are mere moments. A geologist thinks in terms of tens of thousands, hundreds of thousands, or millions of years in the development of the planet. On the Texas coast, however, some aspects of geology are rather sudden. Although the mud base of the area was laid down over geologic time, deltas and barrier islands can be changed overnight. An island beach can be severely eroded Galveston Island Galveston Island Interstate 45 connects Galveston Island with the mainland. The Texas City Dike extends far into the bay system, forming a barrier that separates Galveston Bay from West Bay. The dike was constructed to prevent siltation of the Texas City navigation channel just “inside” the dike but also prevents that sediment from being transported to the marshes of West Bay. A number of marsh restoration projects have been undertaken in this portion of Galveston Bay. TEXAS CITY DIKE GALVESTON TEXAS CITY WEST BAY BOLIVAR PENINSULA VIRGINIA POINT EAST BAY 8 72 The Book of Texas Bays in a matter of hours by a hurricane. A delta can grow a mile in a day after a major flood. Hurricane Alicia scoured 150 feet of beachfront from Galveston Island in the early 1980s. The delta of the Colorado River expanded more than a mile into Matagorda Bay after the 1991 floods. These represent active geological processes— serious change in the here and now. The Doctor and I saw something striking on our first field trip together in 1975: a house sitting in the bay, surrounded by water. It was not a house built on stilts, prepared for possible immersion. This was a normal house, part of the Brownwood residential subdivision in Baytown, surrounded by the water of the San Jacinto River estuary in the lower portion of the Houston Ship Channel. It was in an upper-middle-class neighborhood of pleasant homes—homes for plant managers and professionals. This house was not designed to be surrounded by tidal water, but there it was, stranded. Something had clearly gone wrong. The Doctor strode up to the edge of the bay and talked about the relationship between removal of subsurface water—groundwater—for industrial and municipal usage and the resulting change in the geologic platform of the Houston area. More groundwater had been sucked from the subsurface than was being replenished by recharge rainfall north of Houston, he explained. The water simply could not move fast enough through subsurface sand layers of the aquifer to keep up with the increasing pumpage from water wells. As groundwater was pumped out, the water level in the sands went down, leaving behind clay layers that slowly lost the water within their pores and collapsed. Each time this happened, the geologic platform of the Houston area lost a millimeter or so of elevation. Cumulative impact is a powerful and important concept in environmental thinking, but it can also be hard to grasp. One water well did not cause that house in the Brownwood subdivision to end up in Burnett Bay; hundreds of wells did. The loss of one millimeter at one location did not cause a disaster; but the continuing draining of the clay layers, day in and day out, over a two-county area, was bound to have serious effects. In this manner, the mud platform of the Houston area began to subside in the late 1950s and continued sinking through the 1960s and into the 1970s. By 1975, almost nine feet of land surface had been lost in some areas of the...