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Abstract(s)
Os lameiros sĆ£o prados permanentes seminaturais de montanhas com elevado valor ecolĆ³gico, econĆ“mico, produtivo, paisagĆstico, turĆstico e cultural, pois sĆ£o base para a alimentaĆ§Ć£o da pecuĆ”ria, mantĆŖm a biodiversidade em terras agrĆcolas, sĆ£o importantes na regulaĆ§Ć£o do ciclo da Ć”gua, na formaĆ§Ć£o e retenĆ§Ć£o do solo, e ainda criam manchas descontĆnuas da vegetaĆ§Ć£o, que auxiliam na proteĆ§Ć£o contra incĆŖndios. Diante disso, este trabalho tem como objetivo compreender a resposta hidrolĆ³gica de pequenas bacias hidrogrĆ”ficas de montanhas a partir da determinaĆ§Ć£o de caracterĆsticas fisiogrĆ”ficas das bacias de drenagem de 16 lameiros da Alta Lombada e Onor, do Parque Natural de Montesinho, buscando possĆveis relaƧƵes entre as suas caracterĆsticas e as tipologias de lameiros, quanto Ć presenƧa ou ausĆŖncia de linha de Ć”gua superficial permanente e quanto Ć situaĆ§Ć£o de uso, alĆ©m de compreender a importĆ¢ncia hidrolĆ³gica dos lameiros por meio da distinĆ§Ć£o de algumas caracterĆsticas fisiogrĆ”ficas em relaĆ§Ć£o Ć s Ć”reas ao entorno. A caracterizaĆ§Ć£o foi realizada pela determinaĆ§Ć£o das caracterĆsticas geomĆ©tricas (Ć”rea de drenagem, perĆmetro, Ćndice de compacidade e fator de forma), sistema de drenagem (comprimento do talvegue principal, comprimento total das linhas de Ć”gua, ordem do curso de Ć”gua, densidade de drenagem e percurso mĆ©dio sobre o terreno), relevo (altura mĆ©dia, as altitudes mĆ©dia, mĆ”xima, a 5% da Ć”rea, a 50%, a 95% e a mĆnima, a curva hipsomĆ©trica, o perfil longitudinal do talvegue principal, o declive mĆ©dio da bacia, o Ćndice global de declive, a distribuiĆ§Ć£o dos declives por classes, e o retĆ¢ngulo equivalente), litologia, pedologia e uso e ocupaĆ§Ć£o do solo. Utilizou-se o sistema de informaƧƵes geogrĆ”ficas ArcGIS para obter as informaƧƵes e o software Excel para calcular os Ćndices e realizar as anĆ”lises estatĆsticas. Como resultado, foram obtidas a delimitaĆ§Ć£o das bacias hidrogrĆ”ficas, a caracterizaĆ§Ć£o fisiogrĆ”fica individual de cada lameiro, as comparaƧƵes das caracterĆsticas em relaĆ§Ć£o Ć tipologia de lameiro e a sua interpretaĆ§Ć£o hidrolĆ³gica. TambĆ©m foram obtidas as correlaƧƵes entre as caracterĆsticas e uma breve anĆ”lise das caracterĆsticas diferenciadoras em relaĆ§Ć£o ao lameiro e Ć s Ć”reas ao entorno. As diferenƧas significativas entre as classes de lameiros sĆ£o em relaĆ§Ć£o Ć linha de Ć”gua, e pode-se distinguir as caracterĆsticas em dois grupos: lameiros com rio e sem rio. Verifica-se que as bacias hidrogrĆ”ficas dos lameiros com rio sĆ£o mais extensas, mais desenvolvidas, em um estado maior de equilĆbrio e, com isso, mesmo com maiores fluxos, elas sĆ£o mais distribuĆdas e aproveitadas ao longo da bacia. JĆ” as bacias de drenagem dos lameiros sem rio possuem menores Ć”reas e, com isso, os fluxos sĆ£o menores, mas a velocidade do escoamento Ć© mais elevada e o tempo de concentraĆ§Ć£o Ć© menor, o que ocasiona maiores riscos de cheias e menor retenĆ§Ć£o de Ć”gua. Por meio da correlaĆ§Ć£o entre as caracterĆsticas fisiogrĆ”ficas, foi possĆvel verificar forte correlaĆ§Ć£o positiva entre a Ć”rea, o perĆmetro, o comprimento do talvegue principal, o comprimento total dos talvegues, a ordem do curso de Ć”gua, a altitude mĆ”xima e a altura mĆ©dia, e correlaƧƵes negativas de todas essas caracterĆsticas com o Ćndice de declive global da bacia. Com essas correlaƧƵes, foi possĆvel quantificar os limiares dessas caracterĆsticas para as bacias dos lameiros com rio e sem rio. Na anĆ”lise da diferenciaĆ§Ć£o dos lameiros das Ć”reas de encostas, obteve-se que as Ć”reas de lameiros possuem declividades mais baixas. O comprimento e acĆŗmulo do fluxo sĆ£o muito mais elevados nas Ć”reas de lameiro do que nas demais e, em relaĆ§Ć£o Ć tipologia de lameiro, sĆ£o maiores nos lameiros com linha de Ć”gua permanente. Hidrologicamente, isso demostra que os lameiros sĆ£o mais susceptĆveis a sofrer inundaƧƵes do que as Ć”reas em torno, pois possuem uma menor declividade e um maior acĆŗmulo de fluxo e, com isso, acabam atuando como barreiras de contenĆ§Ć£o de Ć”gua e sedimentos, diminuindo o risco de cheias e erosĆ£o a jusante. Conclui-se que as bacias hidrogrĆ”ficas dos lameiros com rio e sem rio possuem caracterĆsticas fisiogrĆ”ficas diferentes entre esses dois grupos, e isso se reflete no comportamento hidrolĆ³gico. Os lameiros possuem caracterĆsticas diferentes das Ć”reas ao entorno, e com isso um papel fundamental na hidrologia das bacias de montanhas. Por fim, conclui-se que as anĆ”lises por SIG sĆ£o muito Ćŗteis e prĆ”ticas para estudar o ambiente e suas interaƧƵes, e assim caracterizar o comportamento hidrolĆ³gico em pequenas bacias de montanhas parcialmente ocupadas por lameiros.
Lameiros are seminatural mountainous perennial meadows with high ecological, economic, productive, scenic, touristic, and cultural value, since they are the foundation for livestock feed, preserve biodiversity in agricultural land, play an important role on the water cycle regulation, on the soil formation and retention, and create discontinuous patches of vegetation, which help protect against wildfires. In light of this, this work aims to understand the hydrological response of small mountainous drainage basins based on the determination of physiographic characteristics of the drainage basins of 16 lameiros from Alta Lombada e Onor, in Montesinho Natural Park, looking for possible relations between their characteristics and the lameiros' typology, regarding the presence or absence of a permanent surface waterline and the status of use, besides understanding the lameiros' hydrological importance through the differentiation of some of their physiographic characteristics from those of the surrounding areas. The characterization was performed by determining the physiographic (drainage area, perimeter, compactness coefficient, and form factor), drainage system (main thalweg length, total length of the waterlines, stream order, drainage density, and average distance over the terrain), terrain (average height, average altitude, maximum altitude, altitudes at 5%, 50% and 95% of the area, minimum altitude, hypsometric curve, longitudinal profile of the main thalweg, average slope of the basin, the global slope index, the distribution of slopes by class, and the equivalent rectangle), lithological, pedological, and land use characteristics. ArcGIS geographic information system was used to retrieve the information, and Excel was used to calculate the coefficients and to perform the statistical analyses. The delimitation of the drainage basins, the physiographic characterization of each lameiro, the comparison of the characteristics regarding the lameiro typology and their hydrological interpretations were obtained as results. The correlations between characteristics and a brief analysis of the differentiating characteristics regarding the lameiro and the surrounding areas were also obtained. Significant differences between classes of lameiros are related to the waterline, and the characteristics can be separated in two groups: lameiros with and without rivers. The drainage basins of lameiros with rivers are larger, more developed, in a greater state of equilibrium, and therefore, even with greater flows, they're better distributed and used along the basin. On the other hand, the drainage basins of lameiros without rivers have smaller areas, and therefore the flows are smaller, but the flow velocity is higher and the time of concentration is smaller, which results in a greater risk of floods and in a smaller water retention. Through the correlation between physiographic characteristics, it was possible to identify a strong positive correlation between area, perimeter, main thalweg length, total length of thalwegs, stream order, maximum altitude, and mean height, and negative correlations between each of these characteristics and the basin's global slope index. With these correlations, it was possible to quantify the thresholds for these characteristics for the basins of lameiros with and without rivers. Through the analysis of the differentiation between lameiros and sloped areas, it was identified that the areas with lameiros have lower slopes. Length and flow accumulation are much higher in the areas with lameiros than in other areas and, regarding the lameiro typology, they're higher in lameiros with a permanent waterline. From a hydrological point of view, this shows that the lameiros are more prone to floods than the surrounding areas, because they have lower slopes and a greater flow accumulation, and therefore they end up acting as barriers that retain water and sediments, reducing the risk of downstream floods and erosion. It can be concluded that the drainage basins of lameiros with and without rivers have different physiographic characteristics between them, and this is reflected on the hydrological behavior. The lameiros have characteristics that are different from those of the surrounding areas and, as such, they play a crucial role on the hydrology of mountainous basins. Finally, it can be concluded that GIS analyses are very useful and practical to study the environment and its interactions, and hence to describe the hydrological behavior of small mountainous basins partially occupied by lameiros.
Lameiros are seminatural mountainous perennial meadows with high ecological, economic, productive, scenic, touristic, and cultural value, since they are the foundation for livestock feed, preserve biodiversity in agricultural land, play an important role on the water cycle regulation, on the soil formation and retention, and create discontinuous patches of vegetation, which help protect against wildfires. In light of this, this work aims to understand the hydrological response of small mountainous drainage basins based on the determination of physiographic characteristics of the drainage basins of 16 lameiros from Alta Lombada e Onor, in Montesinho Natural Park, looking for possible relations between their characteristics and the lameiros' typology, regarding the presence or absence of a permanent surface waterline and the status of use, besides understanding the lameiros' hydrological importance through the differentiation of some of their physiographic characteristics from those of the surrounding areas. The characterization was performed by determining the physiographic (drainage area, perimeter, compactness coefficient, and form factor), drainage system (main thalweg length, total length of the waterlines, stream order, drainage density, and average distance over the terrain), terrain (average height, average altitude, maximum altitude, altitudes at 5%, 50% and 95% of the area, minimum altitude, hypsometric curve, longitudinal profile of the main thalweg, average slope of the basin, the global slope index, the distribution of slopes by class, and the equivalent rectangle), lithological, pedological, and land use characteristics. ArcGIS geographic information system was used to retrieve the information, and Excel was used to calculate the coefficients and to perform the statistical analyses. The delimitation of the drainage basins, the physiographic characterization of each lameiro, the comparison of the characteristics regarding the lameiro typology and their hydrological interpretations were obtained as results. The correlations between characteristics and a brief analysis of the differentiating characteristics regarding the lameiro and the surrounding areas were also obtained. Significant differences between classes of lameiros are related to the waterline, and the characteristics can be separated in two groups: lameiros with and without rivers. The drainage basins of lameiros with rivers are larger, more developed, in a greater state of equilibrium, and therefore, even with greater flows, they're better distributed and used along the basin. On the other hand, the drainage basins of lameiros without rivers have smaller areas, and therefore the flows are smaller, but the flow velocity is higher and the time of concentration is smaller, which results in a greater risk of floods and in a smaller water retention. Through the correlation between physiographic characteristics, it was possible to identify a strong positive correlation between area, perimeter, main thalweg length, total length of thalwegs, stream order, maximum altitude, and mean height, and negative correlations between each of these characteristics and the basin's global slope index. With these correlations, it was possible to quantify the thresholds for these characteristics for the basins of lameiros with and without rivers. Through the analysis of the differentiation between lameiros and sloped areas, it was identified that the areas with lameiros have lower slopes. Length and flow accumulation are much higher in the areas with lameiros than in other areas and, regarding the lameiro typology, they're higher in lameiros with a permanent waterline. From a hydrological point of view, this shows that the lameiros are more prone to floods than the surrounding areas, because they have lower slopes and a greater flow accumulation, and therefore they end up acting as barriers that retain water and sediments, reducing the risk of downstream floods and erosion. It can be concluded that the drainage basins of lameiros with and without rivers have different physiographic characteristics between them, and this is reflected on the hydrological behavior. The lameiros have characteristics that are different from those of the surrounding areas and, as such, they play a crucial role on the hydrology of mountainous basins. Finally, it can be concluded that GIS analyses are very useful and practical to study the environment and its interactions, and hence to describe the hydrological behavior of small mountainous basins partially occupied by lameiros.
Description
Mestrado de dupla diplomaĆ§Ć£o com a UTFPR - Universidade TecnolĆ³gica Federal do ParanĆ”
Keywords
CaracterĆsticas fisiogrĆ”ficas Hidrologia Geoprocessamento Bacias de montanha Lameiros Abandono do uso da terra