Assessing the impact of Danjiangkou reservoir on ecohydrological conditions in Hanjiang river, China

Natural flow variability is the primary driver of riverine ecosystem function and structure. Alterations in hydrologic regimes modify habitat attributes and impair ecosystem connectivity. The indicators of hydrologic alteration and range of variability approach methods are used to investigate the hydrologic alterations due to Danjiangkou reservoir in the middle stream of Hanjiang river, China, over the past five decades. The results show that Danjiangkou reservoir has significantly changed the ecohydrological flow regime downstream of the dam, especially in the spawning time of the famous four major carps. To minimize the negative ecological impacts, it is necessary to optimize the current operation rules of Danjiangkou reservoir for river ecosystem health protection. We hope the results of the current study could support ecosystem management and restoration plans and provide key ecohydrological parameters for the Danjiangkou reservoir ecological operations in the Hanjiang river.