The cost of ending groundwater overdraft on the North China Plain

Abstract

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.

Using stochastic dual dynamic programming in problems with multiple near‐optimal solutions

“…In practice, however, many water resource management problems are nonconvex. This is for example the case when pumping costs are head‐dependent [ Davidsen et al ., ], or where price is an endogenous variable in hydropower scheduling problems [ Mo et al ., ; Kristiansen , ].…”

Joint optimization of water allocation and water quality management in Haihe River basin

“…Computational resources are therefore not a limiting factor in increasing the spatial resolution of the model area. A spatially much more aggregated modelling study of a single surface water reservoir and one groundwater aquifer, and considering stochastic future inflow, was carried out by Davidsen et al (2016) to study groundwater sustainability in Ziya River basin, North China Plain. The SDP model solved in a coupled LP-GA optimization setup was reported to use 4000 CPU hours to solve a single scenario.…”

Reassessing Water Allocation Strategies and Conjunctive Use to Reduce Water Scarcity and Scarcity Costs for Irrigated Agriculture in Southern Brazil

“…Several past studies have indicated that conjunctive use operations bring much needed increased flexibility to improve water systems' performance and capacity to adapt to future changing conditions [3]. Other studies have demonstrated that ending groundwater overdraft, albeit costly, can have its economic impact greatly reduced through groundwater banking and the use of conjunctive-use infrastructure [4,5]. The behavior of the stream/aquifer system is a key component that can be explored when looking for improved operations, as hydrologic trade-offs.…”