Surface water expansion due to increasing water demand on the Loess Plateau

The Loess Plateau in China Land surface water bodies are important to ensure water security for agricultural, industrial, domestic, and environmental sectors. In the Loess Plateau, changes in land surface water due to climate change and human activities are a concern. Dam and reservoir constructions are effective to combat erosion and water scarcity, but the impact on surface water dynamics is unclear. In this study, we employ a long-term satellite water product to detect the spatial-temporal variability in surface water at the regional scale on the Loess Plateau and identify the potential cause of climate change and human activities. New hydrological insights for the region: Over the past two decades, the area of permanent water has increased by approximately 800 km2. Surface water expansion is primarily associated with small water bodies (< 1 km2), as their number has roughly doubled, while the number and area of large water bodies have remained stable. This expansion has little correlation with precipitation variation but is highly correlated with water withdrawal for agricultural, industrial, and other sectors. Thus, it is primarily contributed by hydraulic project construction as a response to the increasing water demand. The above findings imply the positive role of hydraulic projects, but it is essential to note that the continuous expansion of surface water might not be sustainable because of natural constraints. [Display omitted] •Surface water expansion has occurred during past two decades on the Loess Plateau.•The expansion is primarily contributed from the increased number of small water bodies.•Growing water demand promoted hydraulic project construction and surface water expansion.•Future water availability may not be sustainable partly due to natural constraints.