Human Intervention Will Stabilize Groundwater Storage Across the North China Plain

Abstract

The North China Plain (NCP) has been subjected to groundwater overexploitation over the past decades as a result of rapid socioeconomic development and irrigation water demand with relatively limited renewable water resources. Operation of the middle route of the South‐to‐North Water Diversion Project (SNWD‐M) since December 2014 has provided an opportunity for groundwater sustainability in the NCP by increasing water supply and reducing groundwater abstraction. Water use changes have largely been driven by socioeconomic changes. However, impacts of water diversion, water use change, as well as climate variability in the future on groundwater storage (GWS) in the NCP have not been investigated. This study aims to simulate and project GWS in the NCP during 2005–2050 by incorporating effects of water diversion, water use, and climate variability. The high‐resolution Community Water Model with 30 arcsec spatial resolution was set up to assess interactions between water demand and availability by simulating surface water and groundwater abstraction dynamically. Results show that water diversion and reductions in water use may increase GWS over the NCP in 2050 by 144 mm (19 km3) and 573 mm (75 km3), respectively. Evaluation of GWS among different scenarios shows that combinations of factors, including water use reductions, water diversion, and precipitation variability can contribute up to 73%, 37%, and 32% to GWS stability, respectively. This study highlights the contributions of different management strategies toward sustainable GWS and the importance of water conservation along with diversions.

Characterization of Aquifer System and Groundwater Storage Change Due to South-to-North Water Diversion Project at Huairou Groundwater Reserve Site, Beijing, China, Using Geodetic and Hydrological Data

“…Using a given porosity n and initial storativity S 2 ≈ S 0 , we can determine the mass loadinginduced deformation db u and db c first. Second, using an initial confined water level change dh c = db/S 0 , we can obtain the value of S 2 by employing Equation (7). Then, we update the S 2 and dh c values to reestimate the new values of dh c and S 2 through Equation (7).…”

“…Second, using an initial confined water level change dh c = db/S 0 , we can obtain the value of S 2 by employing Equation (7). Then, we update the S 2 and dh c values to reestimate the new values of dh c and S 2 through Equation (7). We performed this derivation iteratively until the results converged.…”

“…A further improvement of the estimation of storativity is to take into account deformation due to mass loading of the water storage change in both the unconfined and confined aquifers, corresponding to the terms 𝑑𝑏 and 𝑑𝑏 in Equation (7). The calculation of mass loading was performed assuming the deformation of an elastic continuum, with To consider the contribution of water storage change in the unconfined aquifer to the effective stress change, we followed Equation (6), again not considering the vertical deformation caused by the mass loading effect, to estimate the storativity S 1 .…”

“…A further improvement of the estimation of storativity is to take into account deformation due to mass loading of the water storage change in both the unconfined and confined aquifers, corresponding to the terms db u and db c in Equation (7). The calculation of mass loading was performed assuming the deformation of an elastic continuum, with water storage change in the unconfined and confined aquifers as the loading source, and the porosity of the unconfined layer n = 0.21 [47].…”

“…Since 2015, the Central Route of the SNWD Project has transported water from the Danjiangkou Reservoir on the Han river to more than 20 major cities, including the Beijing (population of 21.9 million) and Tianjin (population of 13.9 million) municipalities and other cities in the NCP [6]. The decline rate of groundwater storage in the NCP slowed down during 2015-2018 [7]. Since 2015, when the SNWD Project started to transport water to Beijing, groundwater exploitation was stopped at the HGRS, and groundwater was recharged gradually, which halted groundwater recession remarkably and even resulted in a water table rise after 2015 [4].…”