Impact of the Sanmenxia and Xiaolangdi Reservoirs Operation on the Hydrologic Regime of the Lower Yellow River

To evaluate the alteration of the hydrologic regime in the lower Yellow River caused by the different operational modes of the Sanmenxia and Xiaolangdi Reservoirs, daily stream flow data obtained from the Huayuankou Hydrological Station between 1949 and 2010 were analyzed. The hydrologic regimes before and after different reservoir operations were quantitatively analyzed using the range of variability approach (RVA) based on the indicators of hydrologic alteration (IHA). The results showed that the hydrologic regime of the lower Yellow River changed significantly after the reservoirs began operation, In addition, there was a significant difference in ecohydrological characteristics between operation modes. This research further explains the hydrologic regime of the river. It can be used for future water resources management and ecological scheduling within the lower Yellow River Basin.