The gulf coast aquifer system has provided groundwater for communities along the gulf coast even though it has experienced land subsidence. Despite monitoring, control measures, and management strategies for land subsidence that have been implemented and planned, new exploration of deep aquifers (fresh water and brackish water) and the expansion of new wellfields outside of historical land subsidence areas have created great challenges for future management of regional groundwater resources and control of land subsidence. To predict the behavior of the aquifer in response to future development and increased stresses, we need to have a better understanding of the compressibility of aquifer materials, especially clay lenses within the targeted deep aquifer layers and/or expanded new areas outside of the historical land subsidence area. However, such data are usually lacking due to limited exploration. To fill such a gap, we evaluated different empirical depth-porosity relationships, such as Athy’s and Dickinson’s approaches. The compressibility of aquifer materials was estimated based on the extrapolation of such depth-porosity relationships and limited laboratory test results of soil samples within the area. The applicability and limitations of those porosity-depth relationships are further evaluated with a case study in the Houston area. The result will provide guidelines for the assessment of future subsidence and management strategies in the Houston area as well as other similar coastal aquifers.
