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Groundwater Withdrawals Under Drought: Reconciling GRACE and Land Surface Models in the United States High Plains Aquifer
Author(s) -
Nie Wanshu,
Zaitchik Benjamin F.,
Rodell Matthew,
Kumar Sujay V.,
Anderson Martha C.,
Hain Christopher
Publication year - 2018
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/2017wr022178
Subject(s) - groundwater , aquifer , irrigation , hydrology (agriculture) , environmental science , water cycle , surface water , vegetation (pathology) , irrigation district , water resources , water resource management , geology , ecology , environmental engineering , medicine , geotechnical engineering , pathology , biology
Abstract Advanced Land Surface Models (LSM) offer a powerful tool for studying hydrological variability. Highly managed systems, however, present a challenge for these models, which typically have simplified or incomplete representations of human water use. Here we examine recent groundwater declines in the US High Plains Aquifer (HPA), a region that is heavily utilized for irrigation and that is also affected by episodic drought. To understand observed decline in groundwater and terrestrial water storage during a recent multiyear drought, we modify the Noah‐MP LSM to include a groundwater irrigation scheme. To account for seasonal and interannual variability in active irrigated area, we apply a monthly time‐varying greenness vegetation fraction (GVF) data set within the model. A set of five experiments were performed to study the impact of groundwater irrigation on the simulated hydrological cycle of the HPA and to assess the importance of time‐varying GVF when simulating drought conditions. The results show that including the groundwater irrigation scheme improves model agreement with ALEXI ET data, mascon‐based GRACE TWS data, and depth‐to‐groundwater measurements in the southern HPA, including Texas and Kansas, and that accounting for time‐varying GVF is important for model realism under drought. Results for the HPA in Nebraska are mixed, likely due to the model's weaknesses in representing subsurface hydrology in this region. This study highlights the value of GRACE data sets for model evaluation and development and the potential to advance the dynamic representations of the interactions between human water use and the hydrological cycle.