Effects of check-dams on sediment storage-release in Chabagou Watershed

For clarifying the response of sediment yield to the strengthening of human interventions in the middle Yellow River, Chabagou Watershed was selected as the study area to explore the relationship between development of check-dams and dynamic of sediment storage-release both in time and space. Construction of check-dams in the Chabagou Watershed started in the late 1950s, speeded up swiftly in the 1960s and 1970s, and nearly stopped in the 1980s and 1990s. The results showed that most of eroded sediment was stored in the Chabagou Watershed in the 1980s, with a sediment delivery ratio of 0.325. The low sediment delivery ratio can be attributed to the check-dams, which can not only trap sediment, but also reduce the frequency and intensity of hyper-concentrated flow to a greater extent. However, it is worth noting that the storage capacity of check-dams in the Chabagou Watershed had been decreased significantly due to filling up of early built dams as well as slowdown of dam construction since the 1980s. Moreover, the potentiality of sediment release from destroyed dams is increasing as a result of low design standards and poor maintenance of existing dams. Therefore, the role of check-dams as soil and water conservation measures should be paid adequate attention in the future. It is necessary to strengthen construction and management of check-dams for maintaining and even promoting their sediment trapping capacity.