STUDY OF THE TEMPORAL DYNAMICS OF THE SURFACE OF A LAGOON ON THE NORTH COAST OF RIO GRANDE DO SUL, USING REMOTE SENSING
The Jacaré Lagoon (-29º33'S; -49º81'W // 29°19'48"S and 49°48'39"W), located in a priority area for conservation in the municipality of Torres-RS, is surrounded by a rich mosaic of ecosystems. However, it is under pressure from anthropogenic activities, especially rice farming through surface irrigation and urbanization. The aim of this study was to contribute to the State Environmental Agency's inspection activities in relation to a complaint about a reduction in the area of this lagoon's water mirror, allegedly caused by irregular and excessive water withdrawals. As the variations in the water mirror of the Jacaré Lagoon are little known, we sought to subsidize the investigation by studying the space-time dynamics of its flood surface and the main causes of the variation. Following the characterization of the rainfall regime and normal evapotranspiration in the region, 20 Landsat 5 satellite images and one Landsat 8 image were selected from the months of rice cultivation between 1985 and 2014. In these images, the lagoon's flooded areas were delimited and quantified using the SPRING 4.3.3 application. Comparisons between the variations in the size of the flooded areas and the climate data did not show a significant decrease in the water mirror in the historical series. The results indicate that the dynamics of the surface area of Jacaré Lagoon occurred within the expected seasonal variations, not allowing the assumptions raised in the investigated process to be evidenced. It is also recommended that, among other parameters, more refined remote sensing techniques be used to examine the temporal variation in the coverage of aquatic macrophytes, whose growth towards the interior of the lagoon masks the real size of the lagoon's surface area
STUDY OF THE TEMPORAL DYNAMICS OF THE SURFACE OF A LAGOON ON THE NORTH COAST OF RIO GRANDE DO SUL, USING REMOTE SENSING
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DOI: https://doi.org/10.22533/at.ed.813512507019
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Palavras-chave: Jacaré Lagoon, geoprocessing, rainfall, investigation, temporal variation, area
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Keywords: Jacaré Lagoon, geoprocessing, rainfall, investigation, temporal variation, area
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Abstract:
The Jacaré Lagoon (-29º33'S; -49º81'W // 29°19'48"S and 49°48'39"W), located in a priority area for conservation in the municipality of Torres-RS, is surrounded by a rich mosaic of ecosystems. However, it is under pressure from anthropogenic activities, especially rice farming through surface irrigation and urbanization. The aim of this study was to contribute to the State Environmental Agency's inspection activities in relation to a complaint about a reduction in the area of this lagoon's water mirror, allegedly caused by irregular and excessive water withdrawals. As the variations in the water mirror of the Jacaré Lagoon are little known, we sought to subsidize the investigation by studying the space-time dynamics of its flood surface and the main causes of the variation. Following the characterization of the rainfall regime and normal evapotranspiration in the region, 20 Landsat 5 satellite images and one Landsat 8 image were selected from the months of rice cultivation between 1985 and 2014. In these images, the lagoon's flooded areas were delimited and quantified using the SPRING 4.3.3 application. Comparisons between the variations in the size of the flooded areas and the climate data did not show a significant decrease in the water mirror in the historical series. The results indicate that the dynamics of the surface area of Jacaré Lagoon occurred within the expected seasonal variations, not allowing the assumptions raised in the investigated process to be evidenced. It is also recommended that, among other parameters, more refined remote sensing techniques be used to examine the temporal variation in the coverage of aquatic macrophytes, whose growth towards the interior of the lagoon masks the real size of the lagoon's surface area
- Katia Helena Lipp-Nissinen
- Letícia Sebastião Miranda
- André Luis Domingues
- Galileo Adeli Buriol
