Regional Hydrologic Classification for Sustainable Dam Operations in China: Exploratory Applications in the Yangtze River Basin

Regulated rivers worldwide are managed to meet human demands and reduce flood hazards but the resulting flow regime often fails to support ecological and hydrogeomorphic processes. Designing environmental flows (e-flows) for regulated rivers has been the focus of recent studies, but in the absence of site-specific monitoring data, it can be difficult to assign flow regimes. Given the recent development of dams throughout China, and the desire to minimize adverse downstream ecological effects, we classified river basins to identify characteristics for improved basin management. The purpose of the classification is to minimize the need for localized data when developing initial evaluations for planning e-flow prioritization plans. Building on the functional flow framework of managing rivers to deliver environmental water in the right place, time, and amount, we use k-means consensus clustering to group 185 subbasins of China's Yangtze River into seven hydroclasses (consensus = 0.80). Similar hydrogeomorphic and ecological characteristics are used for the purposes of identifying flow regime components indexed against threatened aquatic species and anthropogenic pressures. This case study can inform water resource management and e-flow requirements broadly. As hydropower dams are expected to more than double over the next 15 years globally, flexible management strategies that balance ecosystem needs with human demands can support efforts for sustainable development.