Modelling Runoff and Sediment Loads in a Developing Coastal Watershed of the US-Mexico Border
Napoleon Gudino-Elizondo,
Trent W. Biggs,
Ronald L. Bingner,
Eddy J. Langendoen,
Thomas Kretzschmar,
Encarnación V. Taguas,
Kristine T. Taniguchi-Quan,
Douglas Liden,
Yongping Yuan
Affiliations
Napoleon Gudino-Elizondo
Department of Civil and Environmental Engineering, University of California, Irvine, CA 92697, USA
Trent W. Biggs
Department of Geography, San Diego State University, 5500 Campanile Dr., San Diego, CA 92182-4493, USA
Ronald L. Bingner
National Sedimentation Laboratory, Agricultural Research Service, USDA, Oxford, MS 38655, USA
Eddy J. Langendoen
National Sedimentation Laboratory, Agricultural Research Service, USDA, Oxford, MS 38655, USA
Thomas Kretzschmar
Departamento de Geología, Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE), Carretera Ensenada-Tijuana 3918, Zona Playitas, 22860 Ensenada, B.C., Mexico
Encarnación V. Taguas
Department of Rural Engineering, University of Córdoba, Córdoba, 14071, Spain
Kristine T. Taniguchi-Quan
Southern California Coastal Water Research Project, 3535 Harbor Boulevard, Suite 110, Costa Mesa, CA 92626, USA
Douglas Liden
USEPA San Diego Border Liaison Office, 610 West Ash St., Suite 905, San Diego, CA 92101, USA
Yongping Yuan
USEPA Office of Research and Development, Research Triangle Park, NC 27711, USA
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.
