Design and installation of runoff-sediment cascade monitoring stations at parallel Qiaozi-East and Qiaozi-West watersheds

Abstract: Monitoring of soil loss at small watershed has significant effect on understanding of soil loss trend, prediction of soil loss damage and selection of directional management measures. Monitoring with control station has been commonly used at parallel small watershed and cascade small watershed, but there is no cascade monitoring at parallel small watershed or no parallel monitoring at cascade small watershed. In this study, the three-class cascade monitoring stations were established at Qiaozi-East and Qiaozi-West watershed on loess plateau, with control areas of 1.0, 0.1, 0.01 km2 grades. The stream network and sub-watersheds were generated from the digital elevation model by GIS, and the location of monitoring stations was made with surveying. According the measured maximum flow rate of Qiaozi-East and Qiaozi-West watershed, the maximum flow rates of second and third cascade monitoring stations were determined. Considering of terrian conditions and the weir-flume property and application, rectangle thin-wall weir and triangle thin-wall weir were selected for second and third cascade monitoring stations respectively. After design and installation, the three-class cascade monitoring stations were completed combined with previous first-level monitoring stations, to measure water level, flow rate and sediment content automatically. The establishment of runoff-sediment cascade monitoring stations will support the study on effect of soil and water control measures, conduct the soil and water control practice at small watersheds, and provide data validation for soil erosion model. It has significant theoretical and practical meaning.