In the San Joaquin Valley of California, approximately 1 million people rely on groundwater for drinking. This high reliance on groundwater has resulted in overpumping of this resource, which leads to subsidence, or massive compression of the ground and arsenic contamination of the water. Arsenic is deadly to human health; therefore, it is imperative that California water agencies and individual water-users pump less groundwater and closely monitor arsenic levels.
Groundwater managers have a difficult time getting a sense of how much water farmers and urban water users extract from aquifers. Gravity Recovery and Climate Experiment (GRACE) is a satellite technology that uses microwaves to generate data that researchers use to build Earth gravity models. The models produced from GRACE data help water managers know how much water farmers and urban water planners have withdrawn from the ground. This helps communities manage their groundwater resources sustainably.