Data for "Watershed and Streambank Erosion Modeling in a Coldwater Stream Using the GWLF-E Model"

Sediment pollution is a major cause of stream degradation throughout the United States. Quantifying this pollution and understanding erosion risk is important for decision makers, but also problematic. Data at the catchment scale is often limited by availability, cost, representativeness, and reliability, making it unrealistic to assess erosion risk over a large area. While many models estimate overland flow related soil loss, streambank erosion is often overlooked and can be the dominant source of sediment in a catchment. We used the Enhanced Generalized Watershed Loading Functions (GWLF-E) model and MapShed plugin for MapWindow GIS to simulate the water budget, field erosion from the landscape, and streambank erosion in 20 subbasins along a gradient of agricultural to urban land cover from 1997-2015 in the Indian Mill Creek watershed of Michigan, USA. Annual water budget results suggest the creek is primarily groundwater fed, but that a per-subbasin average of 6% to 15% of precipitation becomes runoff. Field erosion contributed a per-subbasin average of 0.5 to 2.5 Mg ha-1 yr-1 of sediment, while streambank erosion accounted for 0.2% to 50.1% of the subbasins’ total sediment yields. Average lateral erosion rate of streambanks in subbasins ranged from 0.04 to 7.37 cm yr-1, with 4 subbasins exceeding 1.0 cm yr-1. Urban areas had more streambank erosion than agricultural segments due the runoff from impervious surfaces. Our findings suggest that models that simulate both field and streambank erosion can provide valuable data to prioritize restoration programs that reduce sediment loading.美国全境范围内，沉积物污染均是河流生态退化的主要成因。量化此类污染并明确侵蚀风险，对决策者而言至关重要，但同时也面临诸多挑战。流域尺度（catchment scale）的相关数据常受可获取性、采集成本、代表性与可靠性的制约，导致难以在大范围内开展侵蚀风险评估工作。尽管诸多模型可估算坡面径流（overland flow）引发的土壤流失，但河岸侵蚀（streambank erosion）常被忽视，而其往往是流域内沉积物的主要来源。本研究借助增强型广义流域负荷函数（Enhanced Generalized Watershed Loading Functions, GWLF-E）模型与面向MapWindow GIS的MapShed插件，针对美国密歇根州印第安米尔溪流域内20个子流域（subbasin），模拟了1997至2015年间的水平衡、景观坡面侵蚀以及河岸侵蚀情况，这些子流域的土地覆盖类型沿农业用地向城市用地梯度分布。年度水平衡结果显示，该溪流主要由地下水补给，但各子流域平均有6%至15%的降水转化为径流。坡面侵蚀平均为每个子流域带来0.5至2.5 吨·公顷⁻¹·年⁻¹的沉积物，而河岸侵蚀贡献了各子流域总沉积物输出负荷的0.2%至50.1%。各子流域河岸的平均侧向侵蚀速率介于0.04至7.37 厘米·年⁻¹之间，其中4个子流域的侵蚀速率超过1.0 厘米·年⁻¹。城市区域的河岸侵蚀程度高于农业用地区域，这源于不透水地表产生的径流。本研究结果表明，同时模拟坡面侵蚀与河岸侵蚀的模型，可为确定沉积物负荷削减修复项目的优先级提供极具价值的数据支撑。