基于RUSLE的线状开发建设项目区土壤侵蚀动态监测——以浙江省宁波市北环快速路工程为例

目的]全面调查浙江省宁波市北环快速路施工前后及施工过程中土壤侵蚀时空变化状况,为今后线状生产建设项目水土保持遥感监测提供参考。方法]分别利用2010年宁波市土地利用/覆盖类型图、道路图及调查数据,结合项目区地形图和实测高程点生成的数字高程模型(DEM)、实测土壤属性数据、水文站降雨数据等资料分别获取RUSLE模型中各因子值的空间分布,然后通过RUSLE模型计算项目区3个不同阶段的土壤侵蚀量,最后进行分类统计。结果]项目施工前期和自然恢复期的土壤侵蚀均以微度侵蚀为主,所占项目面积比例分别为98.53%和99.73%;而施工期的土壤侵蚀等级以轻度和微度侵蚀为主,两者分别占项目区面积的52.5%和35.4%;项目施工期的平均土壤侵蚀模数为1 380.9t/(km2·a),远高于施工前及施工期后的251.3,155.4t/(km2·a)。结论]项目施工期土壤侵蚀区域主要分布在临时堆土区,进一步分析发现坡度因素对土壤侵蚀空间分布具有重要影响。

Monitoring Soil Erosion in Linear Production and Construction Project Areas Based on RUSLE-A Case Study of North Ring Expressway in Ningbo City, Zhejiang Province

Objective] In order to provide references for the future remote sensing monitoring of soil and water conservation of the linear production and construction project in Ningbo City of Zhejiang Province, it is crucial to investigate the spatio-temporal distribution of soil erosion in ring expressway before and after construction and construction process.Methods] Land use/cover map of Ningbo City in 2010, topographic map, map of North Ring expressway and field survey data was collected to derive digital elevation model (DEM). Rainfall data was collected from local hydrological station. Based on the collected data, the spatial distribution of the factors in RUSLE model was calculated, and soil erosion maps of the north ring expressway were estimated. Then, the soil erosion amount was calculated at three different stages by using RUSLE model.Results] Slight erosion was dominant during preconstruction period and natural recovery period, which accounted for 98.53% and 99.73%, respectively. During construction period, mild erosion and slight erosion was the largest, which accounted for 52.5% and 35.4%, respectively. The average soil erosion modulus of construction period was 1 380.9 t/(km²·a), which was 251.3 and 155.4 t/(km²·a) higher than that of preconstruction period and nature recovery period, respectively.Conclusion] Soil erosion during the construction period is mainly distributed in the temporary soil ground. Furthermore, the terrain factor has an important influence on the spatial distribution of soil erosion.