The proposed work will evaluate seasonal groundwater dynamics in confined aquifer layers in the Mid-Columbia Basin. Only one Earth Observing remote sensing mission is currently capable of measuring any attribute of groundwater, the Gravity Recovery and Climate Experiment (GRACE) mission from NASA. Preliminary results show that the GRACE-derived groundwater signal is not able to capture confined groundwater trends based on spring high measurements. This proposal will evaluate the larger drawdown flux due to irrigation pumping, and subsequent recharge, to determine if the seasonal variability due to pumping is detectable by GRACE. The study will support future advances in modeling at a higher temporal resolution across the Columbia Plateau Regional Aquifer System, monthly assessments of groundwater vulnerability, and tracking implementation of the Odessa Groundwater Replacement Program.