Gudino-Elizondo Napoleon, Biggs Trent W, Bingner Ronald L, Langendoen Eddy J, Kretzschmar Thomas, Taguas Encarnación V, Taniguchi-Quan Kristine T, Liden Douglas, Yuan Yongping
Department of Civil and Environmental Engineering, University of California, Irvine, CA 92697, USA.
Department of Geography, San Diego State University, 5500 Campanile Dr., San Diego, CA 92182-4493, USA.
Water (Basel). 2019;11(5):1-1024. doi: 10.3390/w11051024.
Urbanization can increase sheet, rill, gully, and channel erosion. We quantified the sediment budget of the Los Laureles Canyon watershed (LLCW), which is a mixed rural-urbanizing catchment in Northwestern Mexico, using the AnnAGNPS model and field measurements of channel geometry. The model was calibrated with five years of observed runoff and sediment loads and used to evaluate sediment reduction under a mitigation scenario involving paving roads in hotspots of erosion. Calibrated runoff and sediment load had a mean-percent-bias of 28.4 and - 8.1, and root-mean-square errors of 85% and 41% of the mean, respectively. Suspended sediment concentration (SSC) collected at different locations during one storm-event correlated with modeled SSC at those locations, which suggests that the model represented spatial variation in sediment production. Simulated gully erosion represents 16%-37% of hillslope sediment production, and 50% of the hillslope sediment load is produced by only 23% of the watershed area. The model identifies priority locations for sediment control measures, and can be used to identify tradeoffs between sediment control and runoff production. Paving roads in priority areas would reduce total sediment yield by 30%, but may increase peak discharge moderately (1.6%-21%) at the outlet.
城市化会加剧片蚀、细沟侵蚀、冲沟侵蚀和河道侵蚀。我们利用AnnAGNPS模型和河道几何形状的实地测量数据，对位于墨西哥西北部一个城乡混合的集水区——洛斯劳雷莱斯峡谷流域（LLCW）的沉积物收支进行了量化。该模型通过五年的径流和沉积物负荷观测数据进行校准，并用于评估在一个涉及在侵蚀热点地区铺设道路的缓解情景下的沉积物减少情况。校准后的径流和沉积物负荷的平均偏差百分比分别为28.4和-8.1，均方根误差分别为平均值的85%和41%。在一次暴雨事件中不同位置采集的悬浮泥沙浓度（SSC）与这些位置的模型模拟SSC相关，这表明该模型能够反映沉积物产生的空间变化。模拟的冲沟侵蚀占坡面沉积物产量的16%-37%，坡面沉积物负荷的50%仅由流域面积的23%产生。该模型确定了沉积物控制措施的优先位置，并可用于确定沉积物控制与径流产生之间的权衡。在优先区域铺设道路将使总沉积物产量减少30%，但可能会使出水口的峰值流量适度增加（1.6%-21%）。
