Using GRACE in a streamflow recession to determine drainable water storage in the Mississippi River basin

Abstract

The study of the relationship between water storage and runoff generation has long been a focus of the hydrological sciences. NASA's Gravity Recovery and Climate Experiment (GRACE) mission provides monthly depthintegrated information on terrestrial water storage anomalies derived from time-variable gravity observations. As the first basin-scale storage measurement technique, these data offer potentially novel insight into the storage-discharge relationship. Here, we apply GRACE data in a streamflow recession analysis with river discharge measurements across several subdomains of the Mississippi River basin. Nonlinear regression analysis was used for 12 watersheds to determine that the fraction of baseflow in streams during non-winter months varies from 52 % to 75 % regionally. Additionally, the first quantitative estimate of absolute drainable water storage was estimated. For the 2002-2014 period, the drainable storage in the Mississippi River basin ranged from 2900 ± 400 to 3600 ± 400 km3.