Evaluation and prediction of water conservation of the Yellow river basin in Sichuan Province, China, based on Google Earth Engine and CA-Markov

Zhichong Yang; Xiaoai Dai; Heng Lu; Chao Liu; Ruihua Nie; Min Zhang; Lei Ma; Naiwen Li; Tiegang Liu; Yuxin He; Zhengli Yang; Ge Qu; Weile Li; Youlin Wang

doi:10.1016/j.heliyon.2023.e17903

Evaluation and prediction of water conservation of the Yellow river basin in Sichuan Province, China, based on Google Earth Engine and CA-Markov

Heliyon. 2023 Jul 1;9(7):e17903. doi: 10.1016/j.heliyon.2023.e17903. eCollection 2023 Jul.

Authors

Zhichong Yang¹, Xiaoai Dai¹, Heng Lu^{2

3}, Chao Liu^{2

3}, Ruihua Nie^{2

3}, Min Zhang⁴, Lei Ma⁵, Naiwen Li^{2

3}, Tiegang Liu^{2

3}, Yuxin He^{2

3}, Zhengli Yang^{2

3}, Ge Qu¹, Weile Li⁶, Youlin Wang⁷

Affiliations

¹ College of Earth Science, Chengdu University of Technology, Chengdu 610059, China.
² State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610065, China.
³ College of Hydraulic and Hydroelectric Engineering, Sichuan University, Chengdu 610065, China.
⁴ School of Environmental and Geographical Sciences, Shanghai Normal University, Shanghai 200234, China.
⁵ School of Geography and Ocean Science, Nanjing University, Nanjing 210093, China.
⁶ State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, Chengdu University of Technology, Chengdu, 610059, China.
⁷ Northwest Engineering Corporation Limited, Xi'an 710065, China.

Abstract

The Yellow River Basin in China has the world's most serious soil erosion problem. The Yellow River Basin in Sichuan Province (YRS), as the upper reaches of the Yellow River, and its water conservation (WC) capacity greatly affects the ecological environment of the downstream basin. In recent years, YRS has received more and more attention, and numerous policies have been developed to improve local WC. However, there is a vacancy in the long-term research of WC in the YRS due to the lack of in-situ data. This study quantitatively evaluated the WC of YRS from 2001 to 2020 through Google Earth Engine (GEE) and analyzed the spatio-temporal variations of WC and land cover (LC). CA-Markov predicted the LC and WC in 2025 under three scenarios to assess the contribution of different scenarios to WC. The WC in YRS fluctuated from 1.93 to 6.77 billion m³. The climate is the dominant factor of WC change, but the effect of LC on WC is also evident. The WC capacity increases with vegetation coverage and height. The WC capacity of forests per km² exceeds 600 mm, while that of grasslands is about 250 mm, and barren can cause around 300 mm of WC loss. In 2025, the WC in YRS may exceed 7.5 billion m³, but the past ecological management mode should be transformed. Improving the quality of land use and converting grasslands to forests is better than reducing cropland to improve WC.

Keywords: CA-Markov; Google Earth Engine; Spatio-temporal analysis; Water conservation; Yellow river.