Cumulative Compaction of Subsurface Sediments in the Chicot and Evangeline Aquifers in the Houston-Galveston Region, Texas (ver. 3.0, March 2022)

The U.S. Geological Survey, in cooperation with the Harris‐Galveston Subsidence District, City of Houston, and the Fort Bend Subsidence District, produced a dataset through 2020 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 14 extensometers at 12 sites that were either activated or installed between 1973 and 1980. The newest extensometer at Fort Bend was installed and activated in 2017. At two of the 12 sites, a pair of extensometers are installed at different depths (one shallow and one deep). The cumulative compaction data for each extensometer are collected about 12 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 the most recently completed year (2020). The amount of compaction for each site visit is determined by subtracting the ending cumulative compaction value from the previously recorded cumulative compaction value.