The Correlation between Current Land Subsidence and Groundwater Levels in Montgomery County, Texas

Houston, a city in Texas, has been affected by land subsidence for nearly a century. Houston and its surrounding areas have been suffering damage associated with faulting and land subsidence severely. In recent years, due to the implemented groundwater regulations, the overall land subsidence rate in the southeastern regions of the Houston metro area has been decreased. However, moderate subsidence (1 to 2 cm /year) is still ongoing in the northern and northwestern regions. Montgomery County is one of the northern areas suffering from infrastructure damages affected by land subsidence. Land subsidence in this region is caused by the overuse of groundwater in Jasper and Evangeline aquifers. This study investigated the vertical ground deformations that are recorded by the Global Positioning System (GPS) and groundwater levels data within Montgomery County. The U.S. Geological Survey (USGS), Lone Star Groundwater Conservation District (LS- GCD), Harris Galveston Subsidence District (HGSD), The University of Houston (UH), and other local agents have been continuously monitoring groundwater and land subsidence for over ten years. By processing USGS groundwater monitoring data and permanent GPS data, this study researched on the correlation between water levels of groundwater and land subsidence. GPS stations recorded land subsidence rates and provided basic information for predicting future land subsidence, which is crucial to better adjust groundwater regulations in the future.