Groundwater supplies drinking water for 51% of the U.S. population, and nearly 99% in rural areas. In many areas, groundwater is being withdrawn at a much faster rate than it can be naturally recharged, leading to land subsidence and impairment of the aquifer. WERRI researchers are developing new methods to accurately predict groundwater transport and aquifer replenishment, groundwater-surface water interactions, and new techniques to accelerate the rate of groundwater recharge using storm runoff.