WILDFIRE EFFECTS ON SUSPENDED SEDIMENT DELIVERY QUANTIFIED USING FALLOUT RADIONUCLIDE TRACERS IN A MEDITERRANEAN CATCHMENT
- Over short and long timescales, wildfires can be an important cause of hydrological and geomorphological change. Mediterranean rivers are part of a fire-prone and high-energy environment in which the timing of major storms in relation to fire influences the impact on fluvial systems; accordingly, the identification of major sources, stores and fluxes of sediments is essential for providing more effective post-fire management strategies. In this study, caesium-137 and excess lead-210 were used as tracers to quantify the proportional contributions of fine sediment from hillslope surface and channel bank sources to suspended sediment and channel bed deposits before the impact of a forest wildfire in Na Borges, a Mediterranean groundwater-dominated river. It also compared burnt and unburnt spatial sources of sediment within a single catchment and the extent to which burnt material was transported downstream. The study focused on two small and steep sub-catchments, where just one of the catchments was partially affected by a wildfire. TheOver short and long timescales, wildfires can be an important cause of hydrological and geomorphological change. Mediterranean rivers are part of a fire-prone and high-energy environment in which the timing of major storms in relation to fire influences the impact on fluvial systems; accordingly, the identification of major sources, stores and fluxes of sediments is essential for providing more effective post-fire management strategies. In this study, caesium-137 and excess lead-210 were used as tracers to quantify the proportional contributions of fine sediment from hillslope surface and channel bank sources to suspended sediment and channel bed deposits before the impact of a forest wildfire in Na Borges, a Mediterranean groundwater-dominated river. It also compared burnt and unburnt spatial sources of sediment within a single catchment and the extent to which burnt material was transported downstream. The study focused on two small and steep sub-catchments, where just one of the catchments was partially affected by a wildfire. The pre-fire dynamics indicated that surface soils were the main sediment source in these ephemeral creeks. Post-fire sediment dynamics were characterised by a single flood event with a short recurrence interval (i.e. return period ca. <1 year). Sediment generated from the burnt area contributed 12% on average to bed-stored sediments within the burnt catchment, which reduced downstream to 5% along the main channel of the Na Borges River. The findings demonstrate the potential for using fallout radionuclide tracers to understand the wider impacts of wildfires on fluvial environments located outside of the burn area. Copyright (C) 2015 John Wiley & Sons, Ltd.…
Author details: | Joan EstranyORCiD, José Andrés López-TarazónORCiDGND, Hugh G. Smith |
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DOI: | https://doi.org/10.1002/ldr.2462 |
ISSN: | 1085-3278 |
ISSN: | 1099-145X |
Title of parent work (English): | Physical review : E, Statistical, nonlinear and soft matter physics |
Publisher: | Wiley |
Place of publishing: | Hoboken |
Publication type: | Article |
Language: | English |
Year of first publication: | 2016 |
Publication year: | 2016 |
Release date: | 2020/03/22 |
Tag: | Mediterranean fluvial systems; fallout radionuclides; sediment delivery processes; sediment source fingerprinting; wildfire |
Volume: | 27 |
Number of pages: | 12 |
First page: | 1501 |
Last Page: | 1512 |
Funding institution: | Spanish Ministry of Economy and Competitiveness [CGL2012-32446]; Balearic Forest Service (Department of Environment, Agriculture and Fishery of the Balearic Autonomous Government); Secretariat for Universities and Research of the Department of the Economy and Knowledge of the Autonomous Government of Catalonia; Economy and Knowledge Department of the Catalan Government through the Consolidated Research Group (RIUS-Fluvial Dynamics Research Group) [2014 SGR 645]; University of the Balearic Islands |
Organizational units: | Mathematisch-Naturwissenschaftliche Fakultät / Institut für Geowissenschaften |
Peer review: | Referiert |
Institution name at the time of the publication: | Mathematisch-Naturwissenschaftliche Fakultät / Institut für Erd- und Umweltwissenschaften |