Ricker Matthew C, Odhiambo Ben K, Church Joseph M
Department of Earth and Environmental Science, University of Mary Washington, 1301 College Avenue, Fredericksburg, VA 22401, USA.
Environ Manage. 2008 May;41(5):766-78. doi: 10.1007/s00267-008-9094-6.
Soil erosion is a serious problem in areas with expanding construction, agricultural production, and improper storm water management. It is important to understand the major processes affecting sediment delivery to surficial water bodies in order to tailor effective mitigation and outreach activities. This study analyzes how naturally occurring and anthropogenic influences, such as urbanization and soil disturbance on steep slopes, are reflected in the amount of soil erosion and sediment delivery within sub-watershed-sized areas. In this study, two sub-watersheds of the Rappahannock River, Horsepen Run and Little Falls Run, were analyzed using the Revised Universal Soil Loss Equation (RUSLE) and a sediment delivery ratio (SDR) to estimate annual sediment flux rates. The RUSLE/SDR analyses for Horsepen Run and Little Falls Run predicted 298 Mg/y and 234 Mg/y, respectively, but nearly identical per-unit-area sediment flux rates of 0.15 Mg/ha/y and 0.18 Mg/ha/y. Suspended sediment sampling indicated greater amounts of sediment in Little Falls Run, which is most likely due to anthropogenic influences. Field analyses also suggest that all-terrain vehicle crossings represent the majority of sediment flux derived from forested areas of Horsepen Run. The combined RUSLE/SDR and field sampling data indicate that small-scale anthropogenic disturbances (ATV trails and construction sites) play a major role in overall sediment flux rates for both basins and that these sites must be properly accounted for when evaluating sediment flux rates at a sub-watershed scale.
在建筑不断扩张、农业生产活动频繁且雨水管理不当的地区，土壤侵蚀是一个严重问题。了解影响地表水体泥沙输送的主要过程，对于制定有效的缓解措施和宣传活动至关重要。本研究分析了自然因素和人为因素（如城市化以及陡坡上的土壤扰动）如何反映在小流域尺度区域内的土壤侵蚀量和泥沙输送量上。在本研究中，使用修订通用土壤流失方程（RUSLE）和泥沙输送比（SDR）对拉帕汉诺克河的两个小流域——霍斯彭河和小瀑布河进行了分析，以估算年泥沙通量率。对霍斯彭河和小瀑布河的RUSLE/SDR分析分别预测出每年298公吨和234公吨的泥沙通量，但每单位面积的泥沙通量率几乎相同，分别为0.15公吨/公顷/年和0.18公吨/公顷/年。悬浮泥沙采样表明，小瀑布河中的泥沙量更多，这很可能是人为影响所致。实地分析还表明，全地形车穿越区域是霍斯彭河流域森林区域泥沙通量的主要来源。RUSLE/SDR和实地采样数据相结合表明，小规模人为干扰（全地形车车辙和建筑工地）在两个流域的总体泥沙通量率中起主要作用，并且在评估小流域尺度的泥沙通量率时，必须对这些区域进行适当考虑。
