IDENTIFYING EPISODIC GROUNDWATER RECHARGE IN ARID REGIONS

Recharge epodicity in arid regions provides a method to estimate annual groundwater recharge given a relationship expressed as the ratio of recharge to precipitation. Traditionally, in-situ observations are required to identify aquifer recharge events, while more advanced approaches such as the water-table fluctuation method or the episodic master recession method are necessary to delineate the recharge event. Our study uses the Gravity Recovery and Climate Experiment (GRACE) observations to estimate monthly changes in groundwater storage which are attributed to the combination of groundwater abstraction and episodic recharge in the arid southwestern United States. The study results clearly illustrate the ability of remote sensing technologies to identify episodic groundwater recharge in arid regions, allowing for groundwater management recommendations.