| Name: | Description: | Size: | Format: | |
|---|---|---|---|---|
| 1.79 MB | Adobe PDF |
Authors
Advisor(s)
Abstract(s)
Um incêndio florestal corresponde a um fogo incontrolado em florestas, matas e outros
espaços com abundante vegetação (matos, áreas de incultos e áreas agrícolas). Os
incêndios florestais são habituais nas áreas de clima mediterrânico, particularmente em
dias quentes e secos, sobretudo quando se associa também o vento forte. Podem ser o
resultado de causas naturais (trovoadas secas), mas, em regra, são devidos a negligência
humana e, muitas vezes, a actos de natureza criminosa.
A expressão "grande incêndio florestal" é utilizada com diferentes significados, sendo,
no entanto associada principalmente ao comportamento do fogo, às caraterísticas e
complexidades do combate e à extensão de área ardida.
O estudo de caso realizado neste trabalho tem como principal objetivo a avaliação da
suscetibilidade à erosão após o efeito do fogo na degradação do solo, visando identificar
as áreas mais críticas, para melhorar os sistemas de proteção já instalados no local e,
assim, mitigar potenciais danos ambientais.
Para tal, aplicou-se uma metodologia que incluiu avaliações no terreno bem como o
tratamento de variáveis espaciais, de forma a poder recolher os diferentes parâmetros de
estimativa da erosividade das precipitações, da erodibilidade dos solos e da topografia,
permitindo a elaboração de mapas de suscetibilidade, com distintos cenários de
utilização do solo, antes e após incêndio.
O local do estudo foi numa pequena bacia elementar da freguesia da Ferradosa no
concelho de Alfândega da Fé, ainda com marcas evidentes do grande incêndio de
Picões, deflagrado no dia 8 de Julho de 2013, afetando uma área total de quase 15000
ha. Foram analisados os diferentes elementos da bacia, tanto as suas caraterísticas
biofísicas como morfológicas, sendo aplicado o modelo de erosão USLE (Equação
Universal de Perda de Solo), com cinco diferentes fatores, com vista a estimar o risco
potencial de degradação do solo para as condições anteriores e posteriores ao incêndio,
neste caso com aplicação de várias medidas de proteção do solo nesta bacia. Para a
aplicação do modelo recorreu-se a um modelo digital terreno (resolução de 5 metros),
combinado com a integração de toda a informação espacial em Sistemas de Informação
Geográfica.
Os resultados obtidos estimam uma severa perda potencial de solo após o incêndio,
indicadora da importância da cobertura vegetal na redução da erosão hídrica. Sendo
assim, é fundamental programar e implementar medidas de proteção do solo pós-fogo, de forma a diminuir a probabilidade de ocorrência de severos danos ambientais nos
recursos solo e água.
Além disso, seria importante nestas abordagens utilizar informação espacial atualizada,
em particular a que integra o fator C e P (coberto vegetal e práticas de uso do solo), de
modo a melhor estimar as taxas atuais de erosão hídrica.
A forest fire corresponds to a controlled fire in forests, woodlands and other areas with abundant vegetation (woods, uncultivated areas and agricultural areas). Forest fires are common in areas of Mediterranean climate, particularly in hot, dry days, especially when it also associates the strong wind. May be the result of natural causes (dry thunderstorms), but as a rule are due to human negligence and often the criminal acts. The term "large forest fire" is used with different meanings, and, though primarily related to fire behavior, the characteristics and complexities of combat and the extent of the burnt area. The case study in this paper aims to assess the susceptibility to erosion after the effect of fire on soil degradation, to identify the most critical areas to improve protection systems already installed at the site and thereby mitigate potential environmental damage. To do this, we applied a methodology which included on-site evaluations and the processing of spatial variables, so that you can collect different parameter estimation erosivity of rainfall, the soil erodibility and topography, allowing the preparation of maps susceptibility, with different scenarios of land use before and after fire. The study site was a small elementary basin Ferradosa the parish in the Customs of the Faith municipality, yet with evident marks of the great walleye, fire, triggered on July 8, 2013, affecting a total area of nearly 15,000 ha. The different elements of the basin were analyzed both its biophysical and morphological characteristics, whichever is the USLE erosion model (Soil Loss Universal Equation) with five different factors in order to estimate the potential risk of soil degradation for to the above conditions and subsequent fire, in this case with application of various soil protection measures in the basin. For the application of the model it used a digital terrain model (resolution of 5 meters), combined with the integration of all spatial information in Geographic Information Systems. The results estimate a severe potential for soil loss after the fire, indicating the importance of vegetation cover in reducing water erosion. Therefore, it is essential to program and implement the post-fire soil protection measures, in order to lessen the likelihood of severe damage to the environmental soil and water resources. It would also be important in these approaches using updated spatial information, in particular integrating the C and P factor (land cover and land use practices) in order to better estimate current rates of erosion.
A forest fire corresponds to a controlled fire in forests, woodlands and other areas with abundant vegetation (woods, uncultivated areas and agricultural areas). Forest fires are common in areas of Mediterranean climate, particularly in hot, dry days, especially when it also associates the strong wind. May be the result of natural causes (dry thunderstorms), but as a rule are due to human negligence and often the criminal acts. The term "large forest fire" is used with different meanings, and, though primarily related to fire behavior, the characteristics and complexities of combat and the extent of the burnt area. The case study in this paper aims to assess the susceptibility to erosion after the effect of fire on soil degradation, to identify the most critical areas to improve protection systems already installed at the site and thereby mitigate potential environmental damage. To do this, we applied a methodology which included on-site evaluations and the processing of spatial variables, so that you can collect different parameter estimation erosivity of rainfall, the soil erodibility and topography, allowing the preparation of maps susceptibility, with different scenarios of land use before and after fire. The study site was a small elementary basin Ferradosa the parish in the Customs of the Faith municipality, yet with evident marks of the great walleye, fire, triggered on July 8, 2013, affecting a total area of nearly 15,000 ha. The different elements of the basin were analyzed both its biophysical and morphological characteristics, whichever is the USLE erosion model (Soil Loss Universal Equation) with five different factors in order to estimate the potential risk of soil degradation for to the above conditions and subsequent fire, in this case with application of various soil protection measures in the basin. For the application of the model it used a digital terrain model (resolution of 5 meters), combined with the integration of all spatial information in Geographic Information Systems. The results estimate a severe potential for soil loss after the fire, indicating the importance of vegetation cover in reducing water erosion. Therefore, it is essential to program and implement the post-fire soil protection measures, in order to lessen the likelihood of severe damage to the environmental soil and water resources. It would also be important in these approaches using updated spatial information, in particular integrating the C and P factor (land cover and land use practices) in order to better estimate current rates of erosion.
Description
Keywords
Incêndios florestais Erosão do solo USLE (EUPS) Alfândega da Fé Sistemas de informação geográfica (SIG)