Methodology for Automatically Delimiting Permanent Preservation Areas Along Water Courses - The Use of Gis in the Hydrological Basin of the Sergipe River, Brazil

Abstract

-Permanent Preservation Areas (PPAs) along watercourses have been the focus of numerous studies, not only because of the fragility and ecological relevance of riverine vegetation, but also because of the inefficiency demonstrated in conforming to the legislation protecting it. One of the major difficulties encountered in terms of guaranteeing the effective conservation of these riverside areas is the absence of methodologies that can be used to define them rapidly and accurately without manually determining the widths of the rivers or assigning only uniform linear values for the entire watercourse. The present work sought to develop a spatial analysis methodology capable of automatically defining permanent preservation areas along watercourses using geographic information system (GIS) software. The present study was undertaken in the Sergipe River basin, "considering the river itself and its principal affluents. We used the database of the Digital Atlas of Hydrological Resources (SEMARH/SE), and the delimitations of the PPAs were performed using ArcGIS 10.1 and the XToolPro 9.0 extension. A total of 5,003.82 hectares of Permanent Preservation Areas were delimited along the margins of the rivers analyzed, with a margin of error of <1% in delimiting the widths of the rivers within the entire area considered. The methodology described here can be used to define PPAs efficiently, relatively rapidly, and with very small margins of error, thus representing a technological advance in terms of using GIS for land management.Key-words: PPA; Mapping; Geographic Information Systems. MÉTODO PARA DELIMITAÇÃO AUTOMÁTICA DE ÁREAS DE PRESERVAÇÃO PERMANENTE AO LONGO DE RIOS -USO DE SIG NA BACIA DO RIO SERGIPERESUMO -As Áreas de Preservação Permanente (APPs) ao longo dos cursos d'água são foco de diversos estudos, não só por sua fragilidade e relevância ecológica, mas pelo ineficaz cumprimento das legislações que a protegem. Uma das maiores dificuldades de garantir a efetiva conservação dessas áreas é a ausência de metodologias que possam delimitá-las rapidamente ao longo de rios sem seccionar manualmente as larguras do rio ou realizar tal procedimento de forma apenas linear para todo o rio. O objetivo do trabalho foi desenvolver um método de análise espacial para delimitar automaticamente a área de preservação permanente ao longo de um curso d'água com a utilização de um Sistema de Informações Geográfica (SIG). O estudo foi realizado na bacia hidrográfica do rio Sergipe, rio que dá nome ao estado, tendo sido aplicada a metodologia aos seus principais rios e afluentes. Para o estudo foi utilizada a base de dados do Atlas Digital sobre Recursos Hídricos -SEMARH/SE, e a delimitação das APPs foi realizada por meio do ArcGIS 10.1 e da extensão XToolPro 9.0. Foi delimitado um total de 5.003,82 hectares de áreas de preservação permanente às margens dos rios analisados, com uma margem de erro inferior a 1% na delimitação da largura dos rios em toda a extensão 230

Riparian forest corridors: A prioritization analysis to the Landscape Sample Units of the Brazilian National Forest Inventory

“…1). The buffers' or APPs' widths were determined applying the methodology described by Jesus and Souza (2016), using data from the hydrological database of the Paraná State (Souza et al, 2011) corresponding to our pilot areas, using GIS software. Given the scale of the hydrological database, a 30-m buffer was applied for rivers featured by lines.…”

“…Given the scale of the hydrological database, a 30-m buffer was applied for rivers featured by lines. As proposed by Jesus and Souza (2016), rivers represented by polygons were converted to polylines, resulting in a vector file corresponding to the river margins to be analyzed. The lines were then segmented, meter by meter.…”