Land subsidence and aquifer compaction in Montgomery County, Texas, U.S.: 2000\u20132020

Brendan Cornelison,Guoquan Wang,Yan Bao,Kuan Wang,Hanlin Liu

doi:10.1186/s40677-021-00199-7

Brendan Cornelison, Guoquan Wang + Show 3 more

Open Access

https://doi.org/10.1186/s40677-021-00199-7

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Abstract

Groundwater-withdrawal-induced land subsidence has been a big concern in Montgomery County, Texas, U.S. since the 2000s. As of 2020, approximately half of the entire county is experiencing subsidence over 5 mm/year. This study aims to investigate ongoing land subsidence in Montgomery County using groundwater-level, extensometer, and GPS datasets. According to this study, land subsidence in Montgomery County since the mid-2000s is primarily contributed by sediment compaction in the Evangeline and Jasper aquifers; the compaction of Jasper aquifer contributes approximately one-third of the land subsidence since the mid-2000s; the pre-consolidation heads of the Chicot, Evangeline, and Jasper aquifers in Montgomery County are close to each other, approximately 15–25 m below mean sea level; the virgin-compaction/head-decline ratio is approximately 1:250 in the Evangeline aquifer and 1:800 in the Jasper aquifer in central and southern Montgomery County. As of 2020, the Jasper groundwater-level altitude is approximately 20–40 m below the pre-consolidation head in the central and southern Montgomery County; the Evangeline groundwater-level altitude is about 40–60 m below the pre-consolidation head. Land subsidence will continue to occur as long as the groundwater-level altitude in either the Evangeline or the Jasper aquifer remains below the pre-consolidation head.

Highlights

Study area Montgomery County is a part of the Houston–The Woodlands–Sugar Land, Texas Metropolitan Statistical Area (MSA), which is often designated as Greater Houston, encompassing nine counties along the Gulf Coast in Southeast Texas with a population of over seven million people at the 2020 census estimates (Fig. 1)
Rapid subsidence up to 20 mm/year was recorded by Global Positioning System (GPS) in northern Harris County and southern Montgomery County during the 2000s (e.g., Welch 2018; Zhou 2020)
The GPS-derived positional time series presented in this study suggest that the rate of subsidence varies considerably over time and space, depending on groundwater levels and the changes of groundwater levels in both the Evangeline and Jasper aquifers

Summary

Introduction

Study area Montgomery County is a part of the Houston–The Woodlands–Sugar Land, Texas Metropolitan Statistical Area (MSA), which is often designated as Greater Houston, encompassing nine counties along the Gulf Coast in Southeast Texas with a population of over seven million people at the 2020 census estimates (Fig. 1). Land subsidence has affected the Greater Houston region for nearly a century. The Woodlands in Montgomery County has become one of the most affected areas by subsidence in the Greater Houston region since the 2010s (Fig. 1). Groundwater-withdrawal-induced land subsidence was reported in southern Montgomery County in the early 1960s (Gabrysch 1967). Rapid subsidence up to 20 mm/year was recorded by GPS in northern Harris County and southern Montgomery County during the 2000s (e.g., Welch 2018; Zhou 2020). The ongoing land subsidence since the mid-2010s is approximately 5–7 mm/year in central Montgomery County and 8–10 mm/year in southern Montgomery County.

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