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 depth-integrated 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. Non-linear 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 2,900 ± 400 km3 to 3,600 ± 400 km3.