Changes in river connectivity indexes in the lower <scp>Yellow River</scp> between 1960 and 2015

Abstract

Abstract Channel connectivity in the lower Yellow River has changed in recent decades as a result of climate change and human activities. Developing indexes that can be used to assess channel connectivity is a key issue in the lower Yellow River and beyond. We propose a suite of connectivity indexes based on several components of a river channel, including boundary, flow, and sediment indicators. Through an analysis of river connectivity over time in the lower Yellow River, we found that a decrease in precipitation was the main cause of poor river connectivity conditions in the 1990s. Since 1999, the year of impoundment of the Xiaolangdi Reservoir, river connectivity has improved, as shown by boundary, sediment, and ecology indexes, as a result of reservoir operation and regulation. However, water diversion may increase channel sedimentation, leading to a decline in sediment connectivity. The suite of river connectivity indexes developed in this paper and applied to the Yellow River can be used in similar sediment‐laden streams in other semiarid regions worldwide.