Particle Size Characteristics of Sediment Sediment Profiles Based on 137Cs Deposited in Small Watershed Check Dam
The analysis of sediment sources in small watersheds is of great significance for the evaluation of comprehensive watershed management and soil and water conservation measures.Using a small karst watershed as an example,starting from the sediment deposition in the check dam of the small watershed,this study examines the depth distribution characteristics of 137Cs specific activity,bulk density,and clay content in the check dam sediment profile and its control of land use types in the watershed,in order to understand the evolution characteristics and driving factors of soil erosion in the watershed.The research results indicate that:①The specific activity of 137Cs in the sediment of check dam varies more complex in the vertical profile,with the maximum value appearing at the bottom and top of the check dam.The specific activity range of 137Cs is 0.99～3.58 Bq/kg,with an average value of 1.8 Bq/kg;②There are significant differences in the distribution of 137Cs specific activities in the surface soil of sloping farmland,grassland,and forest land in the check dam controlled watershed,with 137Cs specific activities ranging widely,at 4.16,2.86,and 6.36 Bq/kg,respectively;③The sediment deposition in the check dam cycle and its control on land use types in the watershed are mainly composed of clay,medium silt,and silt particles,and their proportion of particle size components is basically consistent;④The characteristic parameters of sediment particle size in check dam(median particle size,mode particle size,volume weighted average particle size,and fractal dimension D)vary consistently in the vertical profile,while the variation of effective particle size is more complex.The study provides an important basis for the evolution of sediment source characteristics in mountain flat ponds in karst small watersheds.
karst small watersheds137Cssoil erosionWujiang River Basin
NETL
NSTL
万方数据
