Replication Data for: Freshwater Availability in the Mississippi River Basin and Adjacent Texas Aquifers under Human and Climate Pressures

Water security in the Mississippi River Basin and Texas aquifer region (MRBTX) faces pressure from irrigation demands, climate extremes, and climate change. We integrate groundwater observations, GRACE and GRACEFO total water storage anomalies (TWSA), drought data, climate projections, and irrigation-use analyses to assess aquifer sustainability across MRBTX. A longitudinal gradient exists; arid, irrigation-dependent western provinces show chronic storage deficits, while humid northern and eastern provinces are stable or recovering; a midcontinent transition belt shows minimal change. Groundwater level declines since 1950 average −16.66 ± 0.54 m in the central and southern High Plains and −15.20 ± 3.15 m in the Carrizo–Wilcox. GRACE data shows 85 ± 15 km³ removed from the central and southern High Plains and Texas aquifer since 2002. Gains occur in cooler regions, including 152 ± 57 in Great Lakes and northern Great Plains. The lower Mississippi and Gulf coast show non-significant storage of 32 ± 30 km³. West of 98° W within MRB-TX, droughts occur 1.3–2.0 times per decade lasting 13–15 months, with 2000–2020 irrigation withdrawals averaging 52 km³ yr⁻¹, mostly from groundwater. Climate change is highly to strengthen the east–west gradient under SSP2 4.5, with basin wide annual increases of about 5 to 15 percent driven by robust winter and spring gains in the humid east and north, and little change to slight summer drying in the arid west where model agreement is low. Nine aquifers in northern and eastern MRB–TX are projected sustainable by 2050. The central and southern High Plains and Carrizo–Wilcox are projected to decline −20.02 m and −20.84 m by 2050 at −2.99 and −3.34 m decade⁻¹. Limitations include satellite footprint, well coverage, and diagnostic uncertainties. Solutions include targeted pumping reductions, improved irrigation systems, conjunctive water use, and crop shifts in critical areas. Many provinces can remain secure with these measures; without them, two major aquifers face severe depletion.