172-12 Repurposing State Well-Permitting Records to Detect a Diffuse, Five-Decade Decline in Shallow Groundwater Across Louisiana's Florida Parishes

Session: Environmental Geochemistry and Health (Part II)

Presenting Author:

Mustuque Munim

Authors:

Munim, Mustuque Ahmed¹, Jahan, Shakura², Uddin, Ashraf³, Uddin, Md Riaz⁴

(1) Energy Institute, Louisiana State University, Baton Rouge, LA, USA, (2) Mass Spectrometry Stable Isotopes & Energy Expenditure Lab, Pennington Biomedical Research Center-Louisiana State University, Baton Rouge, LA, USA, (3) Department of Geosciences, Auburn University, Auburn, AL, , (4) Department of Geosciences, Auburn University, Auburn, AL, USA,

Abstract:

Louisiana's eight “Florida Parishes” overlie the Southern Hills regional aquifer system and range from the state’s most urbanized parish to some of its most rural. Outside the Baton Rouge Industrial District, most residents rely on unregulated domestic wells, and the region has no dedicated groundwater-level monitoring network, leaving water-table trends poorly constrained despite decades of uneven population growth. We repurpose 56,116 public water-well registration records from Louisiana’s SONRIS database (wells completed 1970–2025) as a chronosequence proxy for long-term groundwater conditions, using static water level recorded at well completion. Restricting the primary analysis to domestic wells completed in the region’s dominant shallow aquifer (Upland Terrace Aquifer; n=17,930, six parishes), OLS regression with a year-by-growth-group interaction term reveals a statistically significant water-table decline of 1.76 ft/decade (95% CI 1.46–2.07; p<0.001), from a modeled 27.6 ft in 1970 to 37.4 ft in 2025 (8.4 to 11.4 m; a 9.7 ft / 3.0 m drop). This decline rate does not differ significantly between fast-urbanizing and population-stable rural parishes, arguing against a simple local-pumping explanation and pointing to a region-wide signal. East Baton Rouge Parish’s well records let us benchmark this pattern against the well-documented, concentrated drawdown of the Baton Rouge Industrial District’s deep sands within the same dataset: depth to water there is three- to twelve-fold greater than in the shallow regional aquifer. These results show that state well-permitting archives, though never intended for scientific monitoring, can serve as a low-cost complement to sparse formal networks, with direct relevance to unregulated rural domestic-well users.

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