Regional Differences and Influencing Factors of Agricultural and Industrial Water Use Efficiency in Yangtze River Basin

[Objective] This study aims to analyze regional differences in agricultural and industrial water use efficiency in the Yangtze River Basin and their key influencing factors, reveal the spatial differentiation patterns of water use efficiency within the river basin, and provide scientific guidance for formulating differentiated and precise water resource management policies. [Methods] Three provinces (municipalities) from the upper, middle, and lower reaches of the Yangtze River were selected as sample regions. Authoritative data from sources such as the China Water Resources Bulletin, the Water Resources Bulletin of the Yangtze River Basin and Southwest Rivers, and the Statistical Bulletin on National Economic and Social Development from 2014 to 2023 were collected. Core water use efficiency indicators included: effective utilization coefficient of farmland irrigation water, actual irrigation water use per mu of farmland, and water use per 10 000 yuan of industrial added value. Using methods such as descriptive statistics and comparative analysis, the temporal changes and spatial differences in water use efficiency for the entire river basin and between regions were systematically evaluated. Additionally, combined with data on topography, per capita GDP, precipitation, and industrial structure of the sample provinces (municipalities), key factors affecting water use efficiency were qualitatively analyzed and quantitatively identified. [Results] (1) Temporal changes showed that in the past decade, both agricultural and industrial water use efficiency in the Yangtze River Basin gradually improved, but both indicators remained consistently below the national average level, indicating that the overall water-saving potential of the river basin still needed to be tapped. (2) Spatial differences were significant. Agricultural water use efficiency (characterized by the effective utilization coefficient of irrigation water) followed the order of downstream area > midstream area > upstream area. Per capita GDP and topography were key factors affecting coefficient changes. In general, regions with higher economic development level and flatter terrain exhibited higher agricultural water use efficiency. Industrial water use efficiency (characterized by water use per 10 000 yuan of industrial added value) followed the order of upstream area > midstream area > downstream area, with the rationality of industrial structure being its key influencing factor. The downstream area, due to the concentration of high water-consuming industries and a relatively large proportion of water use for direct-current thermal (nuclear) power, had relatively low industrial water use efficiency. (3) Actual irrigation water use per mu of farmland was affected by multiple factors such as cropping structure, climate variability, and irrigation methods. This resulted in poor cross-regional comparability, making it unsuitable as a reliable indicator for evaluating spatial differences in agricultural water use efficiency. [Conclusion] Economic development level, irrigation infrastructure conditions, and the rationality of industrial structure are key factors affecting agricultural and industrial water use efficiency in the Yangtze River Basin. In the upstream area, complex terrain, outdated irrigation facilities, and insufficient financial and technical support lead to significant irrigation water losses during water conveyance and use, resulting in relatively low agricultural water use efficiency. In the downstream area, although water-saving management measures are relatively well developed, the large proportion of high water-consuming industries in the industrial structure results in relatively low industrial water use efficiency. Based on these findings, to improve the overall water use efficiency of the river basin, differentiated and precise zonal management strategies should be implemented. In the upstream area, priority should be given to modernizing irrigation infrastructure and promoting advanced technologies. In the downstream area, efforts should focus on strengthening industrial structure optimization and formulating stricter water-saving standards and incentive-constraint mechanisms for high water-consuming industries. Future research could focus on smaller spatial scales and enhance the quantitative analysis of influencing factors to support the precise implementation of water-saving measures.