Mapeamento de áreas aluvionares no semiárido brasileiro por meio de dados colaterais e imagens orbitais

Abstract

RESUMOA região semiárida do Brasil possui grande potencial para armazenamento de água em áreas aluvionares, podendo potencializar a pequena agricultura. Verifica-se a necessidade de uma metodologia para mapeamento dessas áreas, com o objetivo de futuros estudos in loco para implantação de barragens subterrâneas e manejo correto dos solos aluvionares. Neste sentido, objetivou-se a aplicação de imagens Landsat-Mapeador Temático 5 em conjunto com dados colaterais, como a rede de drenagem, mapa de classes de solo e mapa de relevo para auxiliar na classificação de terraços aluviais. Teve-se, como área de estudo, a bacia do Rio Pajeú, no sertão do estado de Pernambuco. Buscou-se também, por meio de dados SRTM (Shuttle Radar Topography Mission), a avaliação topográfica das áreas classificadas. Verifica-se que a utilização única de dados orbitais traz classificação incongruente mas com a inserção de dados colaterais é possível obter melhores resultados na classificação. A rede de drenagem é fundamental no mascaramento de classificações espúrias. Quando procede à análise topográfica por meio de dados do SRTM das áreas classificadas como terraços aluvionares, observa-se a inconsistência desses dados. Palavras-chave: solos aluviais, classificação supervisionada, sensoriamento remoto, relevoMapping alluvial areas in semi-arid region of Brazil through collateral data and satellite images ABSTRACT The semi-arid region of Brazil has great potential for storing water in alluvial areas, and may give support to small-scale family farming. There is a need to establish a methodology for mapping these areas with the objective of future studies to implement underground dams and suitable management of the soils that occur on alluvial terraces. In this way, the aim of this study was to apply Landsat-Thematic Mapper images together with collateral data such as the drainage network, map of soil classes and elevation data to assist in the classification of alluvial terraces. The study area was Pajeú River basin located in the 'Caatinga' ecosystem of the Pernambuco state. Topographic assessment of the alluvial areas was done by using SRTM (Shuttle Radar Topography Mission) data. It was found that the single use of orbital data brings incongruous classification, but with the inclusion of collateral data it was possible to obtain better results in classification. The drainage network was also important in masking the spurious classification. The analysis of the topography of the classified areas was inadequate using SRTM data.

Peer Review #1 of "Seed germination and early seedling survival of the invasive species Prosopis juliflora (Fabaceae) depend on habitat and seed dispersal mode in the Caatinga dry forest (v0.2)"

“…Manuscript to be reviewed and clay content) and chemical soil attributes [soil organic matter, phosphorus, potassium, calcium, magnesium, sodium, aluminum and cation exchange capacity (CEC)] were also obtained via soil samples per habitat type, with samples at 0-20 cm depth (Lopes et al, 2013).…”

Seed germination and early seedling survival of the invasive speciesProsopis juliflora(Fabaceae) depend on habitat and seed dispersal mode in the Caatinga dry forest

“…Soil moisture was determined by H g; g À1 ð Þ¼ md À mh ð ÞÄmd or H % ð Þ ¼ md À mh ð ÞÄmd  100. Physical (field capacity, sand, silt and clay content) and chemical soil attributes (soil organic matter, phosphorus, potassium, calcium, magnesium, sodium, aluminum and cation exchange capacity (CEC)) were also obtained via 10 soil samples per habitat type, with samples at 0-20 cm depth (Lopes et al, 2013). Soil analyses were performed in the Laboratory for Soil, Water and Plant Tissue Analysis at EMBRAPA Semi-Arid according to standard international protocols (Marques et al, 2007;Galindo et al, 2008).…”

GPR 3d Profile of the Adequateness of Underground Dams in a Sub-Watershed of the Brazilian Semiarid

“…In fact, the GPR method promoted a low number of machine hours for excavation because it allowed detection and localization of smaller sediment thickness associated with greater water storage capacities in the alluvial sub-watershed, which are potential ways of reducing the costs of dam construction. According to Nakashima and Zhou (2001), the GPR method detects the presence of groundwater from multiple and ambiguous reflectors at a depth about 8 m, which provides recognition of the existence of underground water and determination of its depth (i.e. water level).…”

“…Underground dams stand out as one of such alternative technologies directed for semiarid regions with great potential to supply the water demand of families living in rural communities (LIMA et al, 2013;LOPES et al, 2013). In order to store water in the sub-surface, underground dams can be constructed in alluvial rivers and intermittent streams under dry conditions.…”