Measuring ephemeral gully erosion rates and topographical thresholds in an urban watershed using unmanned aerial systems and structure from motion photogrammetric techniques
| Autor: | Eddy J. Langendoen, Douglas Liden, Yongping Yuan, Thomas Kretzschmar, Napoleon Gudino-Elizondo, Ronald L. Bingner, Trent W. Biggs, Carlos Castillo, Kristine T. Taniguchi |
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| Rok vydání: | 2018 |
| Předmět: |
Canyon
Hydrology geography Watershed geography.geographical_feature_category 010504 meteorology & atmospheric sciences Watershed area Ephemeral key Drainage basin Soil Science Sediment 04 agricultural and veterinary sciences Development 01 natural sciences Article Watershed management 040103 agronomy & agriculture 0401 agriculture forestry and fisheries Environmental Chemistry Environmental science Surface runoff 0105 earth and related environmental sciences General Environmental Science |
| Zdroj: | Land degradationdevelopment. 29(6) |
| ISSN: | 1099-145X |
| Popis: | Both rural and urban development can lead to accelerated gully erosion. Quantifying gully erosion is challenging in environments where gullies are rapidly repaired, and in urban areas where microtopographic complexity complicates the delineation of contributing areas. This study used unmanned aerial vehicles (UAVs) and Structure-from-Motion (SfM) photogrammetric techniques to quantify gully erosion in the Los Laureles Canyon watershed, a rapidly urbanizing watershed in Tijuana, Mexico. Following a storm event, the gully network extent was mapped using an orthomosaic (0.038 m pixel size); the local slope and watershed area contributing to each gully head were mapped with a Digital Surface Model (0.3 m pixel size). 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 indicates high vulnerability of unpaved roads 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. Future studies that evaluate effects of different soil types on gully erosion rates for unpaved roads, as well as those that model effects of management practices such as road paving and their impact on runoff, soil erosion, and sediment loads are needed to advance sediment management and planning in urban watersheds. |
| Databáze: | OpenAIRE |
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