Assessing the groundwater deficit for agriculture requirements under precipitation change while achieving food and water security in the North China Plain

Abstract

Groundwater resources are closely related to climate change. Evaluating the groundwater deficit and its variation characteristics under climate change is necessary to understand the risk associated with enhanced groundwater recovery solutions and to provide supporting information for choosing the best technology and risk-reducing measures to implement. In this study, by using the CROPWAT model and copula theory, (1) we developed a groundwater deficit index (Gsci) for agricultural requirements that assesses the risk to groundwater resources imposed by precipitation changes on the North China Plain (NCP), and the four grades of Gsci were high deficit, moderate deficit, low deficit, and no deficit. (2) We estimated Gsci on the NCP for the period 1971–2020 by applying the climatic, soil, crop phenological, and hydrogeology data to the developed index. (3) The occurrence probability of each Gsci grade was evaluated. In the years with abundant precipitation, the occurrence probabilities of no-deficit events were 1, 0, 0, 0, 0.36, 0.56, and 0 on the Yanshan Plain, Taihang-Hebei Plain, Taihang-Henan Plain, Central-Hebei Plain, Central-Shandong Plain, Central-Henan Plain, and Coastal Plain, respectively. (4) The effective precipitation threshold for the occurrence of each Gsci grade was calculated, and the effective precipitation thresholds for the occurrence of no-deficit events were 495 mm, 595 mm, 525 mm, 400 mm, 455 mm, and 555 mm on the Taihang-Hebei Plain, Taihang-Henan Plain, Central-Hebei Plain, Central-Henan Plain, Central-Shandong Plain, and Coastal Plain, respectively. Our findings are useful for assessing the impacts of precipitation changes on groundwater resources and provide a further basis for the design of groundwater resource management strategies with respect to climate change, especially in water‐limited arid agricultural regions.