Subsidence and sea level rise measurements for Houston and Galveston, Texas

The population growth rate in the Gulf of Mexico region is the highest in the United States. This area faces many natural hazards; sea level is rising, and as a result this region is experiencing coastal erosion, in some areas as much as 300 meters inland. Subsidence in conjunction with rapidly rising regional sea levels poses significant risks to coastal communities located within these regions now and in the foreseeable future. This research has investigated ground subsidence and rising sea-surface height occurring within the near vicinity of Galveston Bay by using radar altimetry, GPS, tide gauges, and extensometers. Results provided by radar altimetry found decadal variability (1992-2012) with average rates of sea level rise ranging between 3.0 and 4.0 mm/yr. Decomposition of this regions tide gauges by GPS regional norms are in strong agreement with trends computed from these altimetric sea level anomaly time series. In the vertical direction, the regions of Houston and Galveston were generally found to be stable. However, Seabrook and regions near the inlet of the Houston Ship Channel require continued monitoring due to recent rates of subsidence higher than surrounding areas and regional norms.