Abstract:
Sediment connectivity is an important parameter to characterize the physical cascade relationship of sediment between geomorphic units.It is of great significance to explore the response of sediment connectivity to land use change, which is helpful to reveal the dynamic of runoff and sediment load and evaluate the soil and water conservation capacity of different land use types. In this study, based on the data about land use, runoff and sediment load from 1990 to 2019, the index of connectivity (IC) was used to quantify the spatial and temporal variation characteristics of sediment connectivity and its relationship with runoff and sediment load under the background of land use change in Yanhe River Basin. The results showed that: 1) In recent 30 years, the land use change has been dominated by the Grain for Green, coupled with a small amount of the expansion of construction land in this basin. 2) From 1990 to 2019, the IC showed a downward trend as a whole, with a decrease of 17.85% in 2019. Grain for Green and the expansion of construction land could effectively reduce sediment connectivity, and the former also had longterm ecological benefits. 3) IC had obvious spatial distribution characteristics, which showed an increasing trend from south to north and east to west. Among them, the middle of the basin was the main region of Grain for Green and construction land expansion, and thus significantly reduced sediment connectivity. The northwest of the basin had higher sediment connectivity, and its decreasing extent became smaller with land use change.The sediment connectivity in the south of the basin was lower. 4) There was a significant positive correlation between IC and sediment load (P
