Influence of soil and water conservation measures on reducing in frequency of hyperconcentrated flows in the Wudinghe River basin

Based on data of SSC, precipitation, sand-dust storms and area of soil and water conservation, a study has been made of the temporal variation in the frequency of hyperconcentrated flows in the Wudinghe River, a major tributary of the Yellow River, China. The results showed that the decreasing trend in the frequency of hyperconcentrated flows (F _h) was significant. High-flow season precipitation (P _6–9) decreased slightly, and annual number of sand-dust storm days (D _ss) decreased markedly. Correlation analysis shows that the variation in P _6–9 had little influence on the decreasing F _h, but the decreasing D _ss had significant influence on the decreasing F _h. The 5-year moving average of the frequency of hyperconcentrated flows (F _h,5m) was closely correlated with the area of land terracing, the area of the land created by check dams, the area of tree planting and the area of grass planting. The results of the present study show that the frequency of hyperconcentrated flows can be significantly reduced by soil and water conservation measures. Thus, these results may be useful for decision making for the management of sediment-related disasters in the Wudinghe River basin and in the Yellow River basin.