Assessing risks from groundwater exploitation and utilization: Case study of the Shanghai megacity, China

Abstract

With rapid economic development, demand for water resources is continuously increasing, which has resulted in common overexploitation of groundwater, particularly in megacities. This overexploitation of groundwater over many years has brought a series of adverse problems, including groundwater level decline, land subsidence and hydrogeological issues. To quantitatively describe these risks, we propose a risk evaluation model for groundwater exploitation and utilization. By deducing and expanding on the cusp catastrophe type, this study breaks through the limitations on the catastrophe assessment method, e.g., the number of indicators, and establishes an improved catastrophe assessment model for groundwater exploitation and utilization risk. In addition, the index system of the risk evaluation is constructed including three criterion layers: groundwater system condition (B1), groundwater exploitation and utilization (B2) and groundwater environmental problems (B3) and is tested for the conditions in Shanghai City, eastern China. The evaluation results show that the comprehensive risk values for groundwater exploitation and utilization in all districts (counties) of Shanghai are between 0.68 and 0.85, which categorizes the city as in the moderate risk zone; therefore, the improved catastrophe model is suitable for assessing groundwater exploitation risk in Shanghai City and should be applicable more broadly for the effective protection and sustainable supply of groundwater.