Cumulative Compaction of Subsurface Sediments (2017) in 13 Extensometers in the Chicot and Evangeline Aquifers in the Houston-Galveston Region, Texas

The U.S. Geological Survey, in cooperation with the Harris?Galveston Subsidence District, City of Houston, Fort Bend Subsidence District, and Lone Star Groundwater Conservation District, produced a dataset through 2017 of compaction values in the Chicot and Evangeline aquifers in the Houston?Galveston region, Texas. This dataset contains compaction values of subsurface sediments (mostly in the fine-grained silt and clay layers because little compaction occurs in sand layers) in the Chicot and Evangeline aquifers that were recorded continuously by using analog technology at the 13 extensometers at 11 sites that were either activated or installed between 1973 and 1980. At 2 of the 11 sites, two extensometers are installed at different depths (one shallow and one deep). The cumulative compaction data for each extensometer are collected about 13 times per year during site visits. Cumulative compaction data collected by each extensometer is provided, starting with the data from the year the extensometer was installed through most recently completed year (2017). The amount of cumulative compaction for each site visit is determined by subtracting the previously recorded compaction value from the ending compaction value.