A Laboratory Study On Sediment-storage Effect Of Check-dam Systems In The Small Watershed Of Loess Plateau, China

Check-dam is one of the most effective measures to control soil and water erosion in the Loess Plateau, China. This study presents an approach and the samples for the quasi-scale model experiment on controlling erosion by check-dams, which is different from any previously attempted. First, the orientation and scope were established in the introduction, based on the previous laboratory studies, and the exceptive geographical and climatic condition in the Loess Plateau of China. Subsequently a series of model experiments in various dimensions were operated to investigate the time-variant properties of the runoff and soil loss, and the relationship between them with the rainfall, antecedent moisture, etc. Then the analysis and the interpretation of similarity requirements in the quasi-scale model experiment was presented, with controlled rainfall intensity and similar micro-relief to model the process of soil conservation in the small watershed of Loess Plateau, China, and as a result the experimental data on the model and the prototype had validated the similarity. Finally, runoff/rainfall simulations designed according to above-mentioned method were conducted to research the phenomenon of relative stability and the principle for check-dam programming. The result from this study can be summarized as follows:(1) The flow rate, sediment transportation rate and concentration of the runoff via the outlet approximated to certain constant, soon after the commencement of rainfall simulation, nevertheless the dimension of the model, the intensity or duration of the rainfall were different in the every experiment. In the other hand, for every run of rainfall simulation with the same initial micro-relief without check-dam, with the rainfall in the same duration, and with the bare land in saturated antecedent moisture, the erosion product/rate could be expressed as a power function of the rainfall intensity or the runoff product respectively, and the runoff product/rate could be expressed as a linear function of the rainfall intensity,(2) The method for the quasi-scale model experiment is described as follows: (a) Demanded by the geometrical similarity, the antecedent dimensions of the landform...