University of Twente Student Theses
Post Forest-Fire Runoff & Soil Erosion Modeling with LISEM: A Case Study of Vale Torto – Portugal
Cardoso Reis, Eduardo Amarildo (2010) Post Forest-Fire Runoff & Soil Erosion Modeling with LISEM: A Case Study of Vale Torto – Portugal.
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| Abstract: | This research is intended to strengthen our knowledge and provide further information about the changes that might occur, after induced fire, on some soil physical properties and whether or not they can be quantified or measured. Furthermore, how we can represent (parameterize) such occurrence through use of a physically based model – LISEM, as well as simulate the effects of surface runoff and sediment erosion on the catchment. Several studies have been undertaken, and are available on literatures, on the effects of temperature on soil properties changes, it is known that the severity of the fire and the duration have important roles. Meanwhile, it is also known that their roles are dependant of other factors such as the existence and the quantity of dead and live biomass (combustion), air temperature, humidity, wind and topography of the site. This research, concerning the effects of induced fire on runoff and consequent soil erosion, is inserted within one of the objectives of project DESIRE, which is the establishment of promising alternatives of land use and management. The selected study area, Valtorto catchment, is a 10 ha experimental patch, selected within DESIRE project scope to carry out the fire-induced effects study on soil properties. It is located at around 55 Km west of Coimbra (Portugal), at the Latitude 40° 06’ 21” 0N, Longitude 8° 07’ 05” 60W, and at the Altitude ranging from approximately 600 to 750 meters. The study used LISEM model, and except for DEM derived maps, the remaining required data were directly measured on the field, and in some special cases, literature data were also used. The experimental fire occurred on February 20th 2009, after some failed attempts, due to weather conditions. The fire took approximately 3 hours to consume the entire catchment, and the temperature registered at different soil depth (0 cm, 1 cm and 3 cm). However, the temperature registered on the soil was not significant enough to lead to any changes on soils physical properties. At the depth of 3 cm the registered temperatures ranged from 6.5°C to 22.5°C, which is still within range of low to mild severity fire. The results of statistical analysis carried out (Annexes 2, 3, 4, and 5) of the variance analysis for parameters used in LISEM model for pre and post fire, and they clearly illustrate the significance of the occurred changes. The simulations for Valtorto, the designed storm rainfall, the infiltration decreased from pre fire 95% to 44% post fire, and the total discharge increased from 75m³ to 1,785m³ post fire. Furthermore, due to the changes occurred on the soil surface, the flow detachment increased from 2.8 ton in pre fire conditions to 600 ton post fire. These changes also triggered the total soil loss to jump from the 1.6 ton on pre fire condition to 385 ton post fire, over the entire catchment. Regarding the simulations carried out with the two field storms (moderate and high intensities) showed basically the same trend as the design rainfall. |
| Item Type: | Essay (Master) |
| Faculty: | ITC: Faculty of Geo-information Science and Earth Observation |
| Programme: | Geoinformation Science and Earth Observation MSc (75014) |
| Link to this item: | https://purl.utwente.nl/essays/91582 |
| Export this item as: | BibTeX EndNote HTML Citation Reference Manager |
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