Work

Human-related runoff alteration at large reservoir dam sites in China based on counterfactual natural–actual runoff comparisons

Year: 2026

Type: article

Abstract: Paired Q-CLASS natural and actual runoff reconstructions provide a same-site, same-year reference for human-related departure. Annual series at 907 large-reservoir dam sites in China during 1961–2014 were evaluated using alternative metrics, uncertainty stress tests, multiplicity-controlled temporal tests and cluster diagnostics. The national median relative alteration is $-0.039$ (site-bootstrap 95% confidence interval: $-0.044$ to $-0.035$ ), and 81.59% of sites are negative. Alternative formulations give medians of $-0.041$ to $-0.042$ and negative proportions of 82.91–83.35%. Negative medians are strongest in the Haihe, Huaihe and Yellow River basins, while 67.14% of sites are negative at both the $P_{10}$ and $P_{90}$ annual-runoff states. After trend-free prewhitening and false-discovery-rate control, 281 sites show decreasing and 80 increasing trends; three significant tests have zero median slope. Five-year block-permutation Pettitt tests retain 246 change points, mainly in the 1980s and 1990s, although the count is block-length sensitive. The leading temporal modes are diffuse, and weak cluster separation (maximum silhouette coefficient 0.162) does not support the former five-type interpretation. Q-CLASS point estimates indicate a prevalent, generally modest negative annual departure, but neither resolve reconstruction uncertainty at individual sites nor identify a single causal process.

Source: Scientific Reports

DOI: 10.1038/s41598-026-68478-7

Authors: Qian Chen, Zhiwen Xie

Institutions: The University of Queensland, Hohai University

Language: English

Topic: Hydrology and Watershed Management Studies

Subfield: Water Science and Technology

Field: Environmental Science

Domain: Physical Sciences

SDGs: Clean water and sanitation, Climate action

Open Access status: gold

Estimated APC paid: $2,690