Stream and aquifer water exchange in Mississippi Embayment under intensive pumping and extreme climate: A century-long assessment

The Mississippi Embayment (ME) is one of the fastest groundwater depletion zones in the world. This study investigated stream-aquifer water exchange in the ME over a 115-year period (1900 to 2014) under normal and extreme climates (i.e., precipitation increased and decreased by 20%) with and without agricultural pumping for crop irrigation. The average daily water flow from the aquifer to the streams was always greater than vice versa under all climate scenarios. Under normal climate, the average daily water flow from the aquifer to the streams was 2.52 times larger without pumping than with pumping. While the extreme climate had discernable impacts, the groundwater pumping, but not extreme climate, was the major factor for low flows and drying streams in the ME. These findings are essential to groundwater resource management in the region and provide a critical reference for other parts of the world with similar conditions.