Distribution, failure risk and reinforcement necessity of check-dams on the Loess Plateau: a review

Check-dams are the most important measure to control the soil and water loss in highly erodible catchments on the Chinese Loess Plateau. Based on the data of check-dams from 1950 to 2014, our study roundly analyzed the regional distribution, function and the problems of check-dams on the Loess Plateau. A total of 17,094 check-dams with a storage capacity of over 100,000 m3 and an average density of 0.027 counts km−2 were installed on the Loess Plateau. Check-dams’ densities varied greatly in the Qinghai Province, Gansu Province, Ningxia Hui Autonomous Region, Inner Mongolia Autonomous Region, Shaanxi Province, Shanxi Province and Henan Province. The highest density of check-dams reached 0.088 counts km−2 in Shaanxi Province, whereas the lowest density of check-dams was only 0.005 counts km−2 in Qinghai Province. However, after decades of operation, 3025 large check-dams and 2257 medium check dams are dangerous and have security risks, which are seriously threatening downstream safety. The dangerous rate of check-dams is high. Specifically, the check-dams in Shanxi and Qinghai Province have the highest dangerous rates, with both exceeding 53%. Therefore, there is an urgent need for carrying out reinforcement of the dangerous check-dams. The results are helpful to policymakers to extend and develop check-dams.