Articles | Volume 20, issue 2
Research article
19 Feb 2016
Research article |  | 19 Feb 2016

The cost of ending groundwater overdraft on the North China Plain

Claus Davidsen, Suxia Liu, Xingguo Mo, Dan Rosbjerg, and Peter Bauer-Gottwein

Abstract. Overexploitation of groundwater reserves is a major environmental problem around the world. In many river basins, groundwater and surface water are used conjunctively and joint optimization strategies are required. A hydroeconomic modeling approach is used to find cost-optimal sustainable surface water and groundwater allocation strategies for a river basin, given an arbitrary initial groundwater level in the aquifer. A simplified management problem with conjunctive use of scarce surface water and groundwater under inflow and recharge uncertainty is presented. Because of head-dependent groundwater pumping costs the optimization problem is nonlinear and non-convex, and a genetic algorithm is used to solve the one-step-ahead subproblems with the objective of minimizing the sum of immediate and expected future costs. A real-world application in the water-scarce Ziya River basin in northern China is used to demonstrate the model capabilities. Persistent overdraft from the groundwater aquifers on the North China Plain has caused declining groundwater levels. The model maps the marginal cost of water in different scenarios, and the minimum cost of ending groundwater overdraft in the basin is estimated to be CNY 5.58 billion yr−1. The study shows that it is cost-effective to slowly recover the groundwater aquifer to a level close to the surface, while gradually lowering the groundwater value to the equilibrium at CNY 2.15 m−3. The model can be used to guide decision-makers to economic efficient long-term sustainable management of groundwater and surface water resources.

Short summary
In northern China, rivers run dry and groundwater tables drop, causing economic losses for all water use sectors. We present a groundwater-surface water allocation decision support tool for cost-effective long-term recovery of an overpumped aquifer. The tool is demonstrated for a part of the North China Plain and can support the implementation of the recent China No. 1 Document in a rational and economically efficient way.