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 m^(3) 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 checkdams 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.