Soil erosion and sedimentation processes in the transboundary Tijuana River watershed; Case study: Los Laureles Canyon
The Tijuana River watershed is located in the northwestern Mexico and southwestern USA, the total catchment lies 3,253 km2 in Mexico and 1,212 km2 in the U.S; or 73% and 27 %, respectively. Excessive erosion, transport and deposition of sediment in the watershed have caused many detrimental effects...
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| Format: | doctoral thesis |
| Status: | Published version |
| Publication Date: | 2018 |
| Country: | México |
| Institution: | Centro de Investigación Científica y de Educación Superior de Ensenada |
| Repository: | Repositorio Institucional CICESE |
| Language: | English |
| OAI Identifier: | oai:cicese.repositorioinstitucional.mx:1007/2236 |
| Online Access: | http://cicese.repositorioinstitucional.mx/jspui/handle/1007/2236 |
| Access Level: | Open access |
| Keyword: | info:eu-repo/classification/Autor/Runoff, soil erosion, gullies, sediment production, 3-D photo-reconstruction, AnnAGNPS info:eu-repo/classification/Autor/escorrentía, erosión de suelo, cárcavas, producción de sedimento, fotogrametría 3D. info:eu-repo/classification/cti/1 info:eu-repo/classification/cti/25 info:eu-repo/classification/cti/2508 info:eu-repo/classification/cti/250801 |
| Summary: | The Tijuana River watershed is located in the northwestern Mexico and southwestern USA, the total catchment lies 3,253 km2 in Mexico and 1,212 km2 in the U.S; or 73% and 27 %, respectively. Excessive erosion, transport and deposition of sediment in the watershed have caused many detrimental effects to the people living in the watershed and have resulted in impaired conditions for aquatic life supported in the Tijuana estuary (the outlet of the watershed). This study used Unmanned Aerial Systems (UASs) and Structure-from-Motion (SfM) photogrammetric techniques to quantify gully erosion to calibrated a model (AnnAGNPS) of an ephemeral gully network that formed on unpaved roads following a storm event in an urban watershed (11 km2) in Tijuana, Mexico, a rapidly urbanizing watershed in Tijuana, Mexico. Gullies formed almost exclusively on unpaved roads which had erodible soils and concentrated flow. Management practices (e.g. road maintenance that fill gullies after large storms) contributed to total sediment production at the watershed scale. Sediment production from gully erosion was higher and threshold values of slope and drainage area for gully incision were lower than ephemeral gullies reported for agricultural settings. This indicate high vulnerability to gully erosion which is consistent with high soil erodibility and low critical shear stress measured in the laboratory with a mini jet-erosion- test device. Runoff and soil erosion were simulated for 17 years, and a good correlation between the observed and simulated results was observed (pbias 1.2, RMSE 35% of the mean). Modelled gully erosion was most sensitive to the Soil Conservation Service (SCS) curve number, tillage depth (TD), and critical shear stress. Simulated results show that gully erosion represents about 57% of hillslope sediment production and that 50% of the total sediment yield is produced by only 7% of the watershed area. Future studies evaluating the effect of reduction/prevention of sediment loads from green infrastructure projects, sediment basins, road paving (under different pervious conditions), and the uncertainty of some model estimated parameters, as well as implications in scenario analysis, are crucial for proper sediment management in urbanizing watersheds. |
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