Preprints
https://doi.org/10.5194/hess-2021-240
https://doi.org/10.5194/hess-2021-240

  01 Jun 2021

01 Jun 2021

Review status: this preprint is currently under review for the journal HESS.

Vegetation Greening Significantly Reduced the Capacity of Water Supply to China's South-North Water Diversion Project

Jiehao Zhang1,2, Yulong Zhang3, Ge Sun4, Conghe Song2, Matthew P. Dannenberg5, Jiangfeng Li1, Ning Liu4, Kerong Zhang6, and Quanfa Zhang6 Jiehao Zhang et al.
  • 1Department of Land Management, China University of Geosciences, Wuhan, 430074, China
  • 2Department of Geography, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
  • 3Institute for a Secure and Sustainable Environment, University of Tennessee, Knoxville, TN 37902, USA
  • 4Eastern Forest Environmental Threat Assessment Center, USDA Forest Service, Research Triangle Park, NC 27709, USA
  • 5Department of Geographical and Sustainability Sciences, University of Iowa, Iowa City, IA 52242, USA
  • 6Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, 430074, China

Abstract. Recent global climate change and vegetation greening have important implications to Earth’s global biogeochemical cycles and climate, raising concern about the water supply of water diversion projects. To quantify how such a greening trend impacts local water balance and the capacity of water supply, we built a hybrid model based on the Coupled Carbon and Water (CCW) and Water Supply Stress Index (WaSSI) models. We conducted a case study using the Upper Han River basin (UHRB) in southern China that serves as the water source area to the middle route of the South-North Water Diversion Project (SNWDP). Significant vegetation greening occurred in the UHRB during 2001–2018, with the normalized difference vegetation index increasing at a rate of 0.5 % yr−1 (p < 0.01) but no significant trends in climate during the same period (albeit with high interannual climate variability). Annual water yield (WY) greatly decreased during this period, and vegetation greening alone induced a significant WY decrease of 3.5 mm yr−1 (p < 0.01). Vegetation greening could potentially reduce the annual water supply by 7.3 km3 on average, accounting for 77 % of the intended annual water diversion volume of SNWDP. Vegetation greening could also increase the possibility of hydrological drought and reduce about a quarter of WY on average during drought periods. In the future, water supply capacity is likely to decline further as vegetation greening continues along with increasing temperature and vapor pressure deficit. Our findings demonstrate the large effects of vegetation greening on water balance and hydrological drought, which have important implications for management of water resources in long-range water diversion projects.

Jiehao Zhang et al.

Status: open (until 27 Jul 2021)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on hess-2021-240', Anonymous Referee #1, 17 Jun 2021 reply
  • RC2: 'Comment on hess-2021-240', Anonymous Referee #2, 21 Jun 2021 reply

Jiehao Zhang et al.

Data sets

Vegetation Greening Significantly Reduced the Capacity of Water Supply to China’s South-North Water Diversion Project Jiehao Zhang, Yulong Zhang, Ge Sun, Conghe Song, Matthew P. Dannenberg, Jiangfeng Li, Ning Liu, Kerong Zhang, and Quanfa Zhang https://osf.io/f5bgk/

Model code and software

Vegetation Greening Significantly Reduced the Capacity of Water Supply to China’s South-North Water Diversion Project Jiehao Zhang, Yulong Zhang, Ge Sun, Conghe Song, Matthew P. Dannenberg, Jiangfeng Li, Ning Liu, Kerong Zhang, and Quanfa Zhang https://osf.io/f5bgk/

Jiehao Zhang et al.

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Short summary
To quantify how vegetation greening impacts the capacity of water supply, we built a hybrid model and conducted a case study using the Upper Han River basin (UHRB) that serves as the water source area to world’s largest water diversion project. Vegetation greening in the UHRB during 2001–2018 induced annual water yield (WY) greatly decreased. Vegetation greening also increased the possibility of drought and reduced a quarter of WY on average during drought periods.