Extreme Precipitation Variability and Soil Texture Controls on Water-Table Response

Observed increases in the intensity and duration of extreme precipitation events (EPEs) worldwide are projected to continue with climate change. EPEs can affect water-table dynamics, but the extent of EPE influence and soil texture controls remain poorly understood. We led a one-dimensional modeling effort to examine how EPEs influence water-table dynamics, specifically water-table response time, displacement, recession time, and total recharge. We conducted simulations with EPE amounts of 0.20 m, 0.40 m, and 0.60 m, applied across three durations: 1-day, 7-day, and 20-day, and also used twelve soil textures to examine varying soil texture influence. Results showed water-table response in coarser-grained soils occurs in a manner of days compared to the >200 day response time of finer-grained soils. With increasing EPE amount, water-table response times shortened, varying from ~3 days (sand) to ~239 days (clay). Water-table displacement, calculated as the difference (meters) between the water-table level post-EPE versus steady state, ranged from 0.30 - 1.64 m, and is positively correlated with increasing EPE amount. Despite EPE amount or duration, water-table recession ranged from 1.2 - 3.0 years for all soils. Total recharge is calculated by considering the available porosity and water-table displacement from EPEs, with totals ranging from 17% (clay) to 97% (sand). Recharge appears to be primarily a function of EPE amount and soil properties, with the overall average recharge ~63% of the total EPE amount. Broadly, this modeling effort provides a clearer view of the influence of soil texture on groundwater response to EPEs.