| This research adopted a model, Revised Universal Soil Loss Equation (RUSLE), to analyze the risk pattern of water loss and soil erosion in the road effect zone of Hangjinqu highway basing on the DEM data, rainfall records, and structural data of soil and Hangjinqu highway of Zhuji City, Zhejiang Province. The main content of this research included:calculating the risk pattern of soil erosion by comprehensive analyzing of each factors in the equation, comparing the soil erosion situation before and after the construction of this road by using buffer analysis, analyzing distribution rule of soil erosion after the construction of this road, and coming out with certain protection methods.The conclusions were as follows:(1) According to the calculation result of RUSLE model in the research area, the estimated average soil loss in tons per acre per year A before the construction of road was0～380.02(t·hm-2·a-1), and the A after the construction fell among0～572.94(t·hm-2·a-1).(2) The soil in Zhuji was separated into different levels by its erosion condition according to the criterion. As the result shown in this RUSLE model, for low level of risk soil the construction of road increased the road soil erosion, which means the proportion of soil erosion before road construction was higher than that when road construction was completed. Whereas the proportion of soil erosion before road construction was much lower for the high level of risk soil. The most dramatic soil erosion effect zone of Hangjinqu Highway was660meters.(3) The intensified degree of landscape fragmentation and the increased proportion of construction land which were caused by road construction were the main reasons for severe soil erosion. The result indicated that there was a significant correlation between the degree of landscape fragmentation and soil erosion as the increasing of landscape fragmentation would cause the intensification of the soil erosion risk. The correlation analysis of soil erosion and construction land also confirmed that the increasing of construction land would exacerbate the risk of soil erosion. As a result, soil and water conservation of highway should focus on these two aspects and take the appropriate measures.(4) The impact of soil erosion caused by highway construction should be taken into consideration at the beginning of the road planning. The quantitative prediction method can be applied to road selection. The result of this research showed that the most dramatic soil erosion effect zone of Hangjinqu Highway was660meters, so a series of measures should be taken to protect from soil erosion in this zone. Among all the factors related to RUSLE model, it was difficult to alternate R (rainfall-runoff erosivity factor) and K (soil erodibility factor) as they were mainly determined by natural dynamic and the economic situation of Zhuji City. However, the factors of LS(slope length factor and slope steepness factor), C(cover-management factor) and P(support practice factor) were relatively changeable by manpower, so some methods of water and soil conservation, such as the transformation of planting mode and improvement of vegetation coverage, could be considered to solve soil erosion problems. |
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