Experimental Research about the Influence of Grass Coverage on Loess Slope Runoff Sediment Yield

Abstract

It was important to explore the law of water and sediment reduction of loess slope in different grass coverage for carrying out the grass construction and controlling slope erosion in the Loess Plateau. Using the tests of outside artificially runoff erosion simulation, in the condition of 5L/min of the scouring flows, we conducted a pilot study of sediment yield, erosion rates, and runoff sediment concentration in three different slope conditions of 15°, 20°, 25° and three grass coverage conditions of bare slope, 30%~40% and 70%~80%. The results showed that: the grass coverage has significantly influences on sediment yield, erosion rate and runoff sediment concentration of loess slope. Sediment yield of loess slope with grass coverage of 70 ~ 80% is less than 10% of that of bare slope. Under the same conditions of gradient and grass coverage, the sediment yield and runoff sediment concentration had a direct proportion with the scouring flow. Under the same conditions of gradient and scouring flows, the erosion rate and runoff sediment yield of loess slope are basically the same. Grass has a significant role in enhancing resistance to corrosion of soil and reducing erosion of loess slope.