The Columbia Plateau Regional Aquifer System (CPRAS) is a multi-layered basalt aquifer system in Washington, Idaho, and Oregon. Despite the hydrologic dominance of the Columbia River, the CPRAS is playing an increasingly important role in supporting water demands in the Pacific Northwest. NASA’s Gravity Recovery and Climate Experiment (GRACE) satellite mission has created an unprecedented opportunity to understand large-scale groundwater dynamics. In this talk, we question the accuracy of GRACE-derived observations of groundwater storage change in the deep, confined groundwater layers from which most water is pumped in the CPRAS and discuss how best to leverage remotely sensed and other observations in support of sustainable groundwater management in heterogeneous, confined groundwater systems.