Estimated subsidence in feet from 1906-2016 using measured land surface elevation change at benchmarks surveyed in 2000 and estimated annual subsidence rates from 2011-2016 at HGSD GPS subsidence network assuming a constant rate of subsidence from 2010-2016. Subsidence has occurred throughout the region has a result of groundwater development. Data source: Thompson, Robert, William M. Chrismer, and Christina Petersen. May 2019. 2018 Annual Groundwater Report. Harris-Galveston Subsidence District https://hgsubsidence.org/wp-content/uploads/2019/11/2018-HGSD-Annual-Groundwater-Report.pdf. District surveys and active monitoring shows estimated subsidence magnitudes greater than 1 foot since 1906 exists in all adjacent counties. Disclaimer: This product is for informational purposes only and may not be suitable for legal, engineering, or surveying purposes. It does not represent an official survey and represents only the approximate relative location of features and boundaries. Mapping may not necessarily reflect on-the-ground conditions. This product and those involved in its production make no claims as to the accuracy or reliability of the data, and neither assumes, nor will accept liability for their use.