Impact of Land Use Change and Dam Construction on Soil Erosion and Sediment Yield in the Black Soil Region, Northeastern China

Since the 1960s, the implemented soil conservation measures on steep slopes and the densely planted shelterbelts as well as the constructed reservoirs and ponds in Baiquan County, northeastern China have dramatically altered the landscape and would greatly influence soil erosion and sediment yield (SY). However, how these land use changes and the constructed dams affected soil erosion and SY still remained unclear. A physically distributed soil erosion model WaTEM/SEDEM that has been calibrated and validated using 25 reservoir SYs in the study area was applied using nine land use scenarios (land uses in 1954, 1975 and 2010, each with 8, 32 and without dams) to assess their impacts on sediment delivery at the Shuangyang catchment (915km(2)). The results show that land use changes as well as the increased dam numbers progressively decreased catchment sediment delivery and the impact of dams on sediment delivery was more efficient under the intensified land use condition (1954 land use without reservoirs). With respect to 1954 land use without dams, current land use condition (2010 land use with 32 dams) was simulated to decrease SY by 618%. Soil conservation measures (terrace and contour tillage as well as shelterbelts) on the slopes greatly influenced SY and over 80% of the reduced SY were caused by land use changes. This study indicates that soil conservation measures are sustainable sediment control measures for the black soil region because the accumulation of sediment in dams causes shortening of the useful life in reservoirs and ponds and implies increasing financial costs. Copyright (c) 2016 John Wiley & Sons, Ltd.