Research On The Red Line Of Water Conservation In Typical Semi-arid Region

In this paper, we take Wudinghe watershed as the research area. By using the water balance method, we calculate the water output and the surface runoff of Wudinghe watershed, and on this basis, we calculate the average for ten years of the water conservation value in Wudinghe watershed. Finally, by analyzing the spatial differentiation of the water conservation in Wudinghe watershed and based on the dividing principle of the red-line areas of ecology, the research area is partitioned. The main conclusions are as follows:1. The average annual precipitation of Wudinghe watershed is 449.3mm, and the Lijiachuan watershed whose mean annual precipitation is the highest:508.65mm, is located on the southeast of the research area. And the Heihezi watershed which is located on northwest of the research area has the lowest mean annual precipitation:394.60mm. The potential evapotranspiration of the research area is calculated according to the Hargreaves equation. In space, the potential evapotranspiration presents the trend of decreasing from north to south, the maximum value of the mean annual potential evapotranspiration is 143.5mm, and the minmum value is 16.3mm.2. The surface runoff of the research area is calculated by using the SCS model, and the mean annual surface runoff depth is 44.8mm. The value of most areas are below 117mm. The surface runoff of the research area is affected by the combination of land use types, hydrologic soil group and the antecedent moisture conditions of soil. In situations where the land use type is forest or brush, or the soil is with loosen texture, or the antecedent moisture conditions of soil is relatively low, it is benificial to infiltrate for the precipitation. Therefore the surface runoff is small and vice versa.3. The water conservation value of Wudinghe watershed ranges from 0 to 135mm, and the north is better than the south. It is noteworthy that because of the low temperature, low evapotranspiration, soil with loosen texture, great infiltration capacity and small surface runoff, therefore the research area has great water conservation capacity although the northwest of the research area is sand area and the precipitation is low.4. The total area of the ecological red line of the Wudinghe watershed is patchy in distribution at the northwest and along the south margin of the watershed.And it is linearly distributed in each branch.It is recommended that the protectionand management of the total area of the ecological red line of the Wudinghe watershedshould be under unified management and supervision of environmental protection deparment.Also,setting a detailed differences in management program is recommended.