Runoff and sediment yield characteristics of earth road under artificial rainfall and simulated overland flow tests conditions in Loess Plateau

An artificial rainfall and simulated overland flow test was conducted to study runoff and sediment yield process and hydraulic characteristics of uncovered earth road and grass-covered earth road in order to decrease soil and water loss on grass-covered earth road surface. Total runoff and sediment yield decreased 3.94%-25.10% and 9.65%-45.69% respectively of grass-covered earth road compared with uncovered earth road. At same flow rate, grass-covered earth road had lower soil erosion rate, runoff velocity and unit energy of water-carry section. Darcy-weisbach resistance coefficient and Manning roughness coefficient of grass-covered earth road was 2.62-9.00 times higher and 1.74-3.53 times higher respectively than that of uncovered earth road. Because of its lower runoff velocity and unit energy of water-carrying section, higher road surface roughness coefficient and runoff resistance coefficient, grass-covered earth road had a lower sediment yield and could decreased sediment transport. The study provides theoretical support for decreasing uncovered earth road erosion and paving grass-covered earth road.