Lakes declining in the mega-Changjiang River Basin in China

Bu F, Dai Z, Long C, Yang J, Mei X, Chu A. 2025. Lakes declining in the mega-Changjiang River Basin in China. Lake Reserv Manage. 41:1–15. Global lakes are shrinking due to intensive human interference and climate change. However, a comprehensive understanding of lake variations within mega river systems has been poorly documented. Here, lake dynamics of the mega-Changjiang River Basin (CRB) are explored by multiple images and hydrological observations between 1990 and 2020. The lake area in the CRB declined significantly by 91.58 km²/yr and 101.11 km²/yr in the flood season and dry season, respectively, while the lake number only exhibits an obvious decrease of 0.25 lakes/yr in the flood season. Furthermore, small lakes remain relatively stable, and medium-size lakes experience a minor decline/increase during the flood/dry season, while large lakes exhibit an intensive decrease during the dry season. Lakes in the upper Changjiang increase in area due to glacier melting caused by rising temperatures. Lake area declines in midstream and the lower stream were induced by Changjiang riverbed downcutting triggered by Three Gorges Dam regulation, as well as by large-scale human reclamations. In addition, seasonal differences in precipitation can cause lake size fluctuations from the flood season to the dry season. Our results underscore the response of the lake system to anthropogenic interference and climate change, providing valuable insights for sustainable lake management and protection.