Vector dataset of rivers, lakes/reservoirs and their Spatial connectivity in High Mountain Asia

Significant changes in snow, glaciers, and the water system across High Mountain Asia (HMA) under global warming have intensified regional water system instabilities. Accurate mapping of the spatial distribution and connectivity of rivers and lakes is essential for understanding and managing the regional water balance and ecosystem. However, existing surface water datasets lack clear distinctions and connectivity information between flowing rivers and lakes. In this study, three vector datasets over HMA were developed – Rivers, Lakes, and River–Lake spatial Connectivity ­– based on the European Space Agency's (ESA) WorldCover data and the 2020 Global Surface Water dataset from the European Commission's Joint Research Centre (JRC). Rivers and lakes were extracted separately using Geographic Information System tools for all basins in HMA and incorporated into a surface water time series. The analysis result shows that the total area of rivers and lakes in HMA increased by 23.5% from 2000 to 2019, with lakes accounting for 78.3% of this expansion, while river areas expanded by 40.8%. Glacier-fed rivers and lakes contributed 75.5% of the total water area increase though non-glacier-fed waters exhibited a higher relative growth (44.8%), compared to glacier-fed ones (20.4%). In the endorheic basins, a consistent annual increase of lake area from 2000 to 2019 was evidenced: the area of hydrological connected lakes and rivers expanded from 20,782 km² to 25,396 km². In contrast, the area of isolated lakes grew from 9,550 km² to 12,970 km². Statistical analysis revealed a significant correlation between lake area expansion and precipitation. The datasets developed in this study provide the fundamental basis for analyzing changes of rivers and lakes in HMA, along with their connectivities, supporting regional water resource management, ecological conservation, and sustainable agricultural and pastoral development.