Geospatial analytics of driving mechanism of land subsidence in Gulf Coast of Texas, United States

Muhammad Younas; Shuhab D Khan; Osman Tirmizi; Younes Hamed

doi:10.1016/j.scitotenv.2023.166102

Geospatial analytics of driving mechanism of land subsidence in Gulf Coast of Texas, United States

Sci Total Environ. 2023 Dec 1:902:166102. doi: 10.1016/j.scitotenv.2023.166102. Epub 2023 Aug 8.

Authors

Muhammad Younas¹, Shuhab D Khan², Osman Tirmizi¹, Younes Hamed³

Affiliations

¹ University of Houston, Department of Earth & Atmospheric Sciences, Houston, TX, USA.
² University of Houston, Department of Earth & Atmospheric Sciences, Houston, TX, USA. Electronic address: sdkhan@uh.edu.
³ University of Gafsa, Department of Earth Sciences, Laboratory for the Application of Materials to the Environment, Water and Energy (LAM3E), Gafsa, Tunisia.

PMID: 37558064
DOI: 10.1016/j.scitotenv.2023.166102

Abstract

Land subsidence has been an ongoing issue for over a century along the Gulf Coast of Texas in the United States. This study assesses and models the factors contributing to land subsidence covering fifty-six (56) counties along the Gulf of Mexico coastline from Louisiana to the border of Mexico, approximately 300,000 km². Geospatial statistical techniques and regression models were employed to investigate and predict the fundamental causes of land subsidence by integrating multiple datasets such as Global Navigation Satellite System (GNSS) (147 stations), groundwater extraction (78,420 wells), hydrocarbon production (84,424 wells), precipitation, and population growth. In the last two decades, the overall population rose by 33 % and the compound annual population growth rate increased from 2.08 to 4.10 % in Montgomery, Waller, Fort Bend, and Chambers counties. Emerging hotspot analysis reveals that the groundwater level is persistently declining and the regression model (R² = 0.92) tested over Harris County predicts that the population growth significantly contributes to land subsidence in this region. The groundwater withdrawal rate is increased from 23 to 96.6 billion gallons in Harris, Montgomery, and Fort Bend counties in the last two decades. A prolonged drought from 2010 to 2015 due to low precipitation affected all fifty-six counties. Oil production increased eightfold and a high extraction rate of 19.5 to 40.1 million bbl/yr of oil in Karnes County was recorded within the last 20 years. The regression model (R² = 0.73) over this county suggests that oil extraction is a primary contributing factor to the observed subsidence. Although the gas extraction rates for all counties are decreasing over time, some counties in the southern part of the Gulf Coast Aquifer show relatively higher extraction rates. For the first time, this research determines that all fifty-six counties along the Gulf Coast of Texas are undergoing land subsidence and experiencing high population growth, groundwater withdrawal, and hydrocarbon extraction.

Keywords: Emerging hotspot; GNSS; Groundwater withdrawal; Hydrocarbon extraction; Land subsidence; Regression modeling.