Inter-basin water transfer compensates for unsustainable water use in the North China Plain

Authors: DONG, J. - Tianjin University; LI, Y. - Tianjin University; WEI, L. - Nanjing University; TANGDAMRONGSUB, N. - University Of Maryland; Crow, Wade; CHEN, X. - Tianjin University

Submitted to: Nature Climate Change
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/10/2023
Publication Date: 12/18/2023
Citation: Dong, J., Li, Y., Wei, L., Tangdamrongsub, N., Crow, W.T., Chen, X. 2023. Inter-basin water transfer compensates for unsustainable water use in the North China Plain. Nature Climate Change. Article e2023WR035129. https://doi.org/10.1029/2023WR035129.
DOI: https://doi.org/10.1029/2023WR035129

Interpretive Summary: Irrigation agriculture is becoming increasingly important for ensuring global and regional food security. Unfortunately, it is often based on the unsustainable use of existing groundwater resources. This has led to the increased use of inter-basin transfer systems that attempt to meet unsustainable irrigation demand in arid areas via the transfer of water from neighboring basins with more extensive water availability. The efficient managing of such systems requires access to accurate water budget information to balance crop water use and soil water storage with - potentially expensive - inter-basin water transfers. This paper develops a remote sensing approach for such budgeting and applies it to an existing inter-basin water transfer system in the North China Plains. The analysis shows that the system is currently delivering a sufficient volume of water to offset the intensification of irrigation water use in the region. In the future, this approach will be used by water resource managers in the Western United States faced with similar management issues in highly irrigated areas.

Technical Abstract: The North China Plain (NCP), contributing approximately 20% of China’s grain yield, is a global hotspot of freshwater depletion. In response, the world’s largest Inter-basin water transfer (IBWT) projects have been implemented to stabilize NCP terrestrial water storage (TWS) levels. However, the effectiveness of IBWT on NCP TWS restoration remains unclear, particularly under future elevated CO2 conditions. Here we provide a physically based framework to robustly reconstruct TWS anomalies (TWSA) that is subsequently used to disentangle climate and anthropogenic effects on NCP TWSA. Results show that the NCP TWSA depletion rate was significantly attenuated in 2015 – 2021, which is primarily attributable to recently enhanced IBWT activities, mainly via the operation of south-north water division. Without increasing IBWT, average NCP TWS would currently be 94.9 ± 4.9 mm (or 12.2 ± 0.6 km3) lower. However, the positive effect of IBWT is partly offset by increased crop water consumption over the NCP region (-24.1 ± 5.2 mm or -3.1 ± 0.7 km3). Under elevated CO2 conditions, future climate and vegetation density changes will strongly enhance NCP TWS depletion rates. Nevertheless, maintaining current IBWT levels and vegetation density (via agriculture management) is likely adequate to stabilize future NCP TWS. Although IBWT has a dominant impact on long-term NCP TWS levels, agriculture management remains critical. In the absence of appropriate agriculture management, a 70% increase in IBWT volumes and large associated financial costs, may be required to stabilize future TWS levels in the NCP.