Fragilidade ambiental e qualidade da água na Bacia do Rio Almada Bahia

• Autor(a) principal: Franco, Gustavo Barreto
• Data de Publicação: 2010
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/823
• topic: Diagnóstico ambiental; Uso e ocupação do solo; Planejamento ambiental; Environmental diagnosis; Soil use and occupation; Environmental planning; CNPQ::ENGENHARIAS::ENGENHARIA CIVIL::GEOTECNICA

This research had the aim of realize a diagnosis of the water quality and the environmental fragility of the Almada River Watershed (ARW), Bahia, Brazil. This way, it was realized the characterization of the study area based on primary and existent data; elaboration of the soil map starting in the interpretation of the landscape and the sixty soil profiles distributed in the watershed, in addition to physical and chemical analysis of thirty profiles and mineralogical analysis in representative samples; determination of the environmental fragility degree; evaluation of the water quality in twelve sampling locations covering physical, chemical and biological characteristics; calculation (measurement) of the Water Quality Index (WQI); and finally the correlation between WQI, soil use and occupation and the environmental fragility. The environmental fragility map generated from the integration of the climate characteristics, geology, slope, soil, soil use and land occupation, was algebraically manipulated in a Geographical Information System (GIS) at the scale of 1:100.000, being classified into five degrees of fragility, thus identified: very low, low, medium, high, very high. Major fragilities include the urban areas, the sand sediment exposed in the coast zone, mangrove and degraded of the coast plain located in the east portion and the pasture areas and exposed soil in the west portions of the watershed. In the classes that presented low fragility are included the rocks with crystalline basement, covered by the rainforest and Cocoa Agroecosystems. The obtained results in the water quality evaluation allowded to define that its deterioration occurs in some parts of the watershed, specially downstream urban areas, primarily because of the discharge of effluents, highlighting the domestic sewage. The understanding of the WQI with the soil use and occupation and the environmental fragility have demonstrated that there is no good relation between these variables, due to the natural characteristics of the watershed and the point sources of pollution. The raised and analyzed information constitute in products that can subsidize the decision making, prioritizing actions that will minimize the environmental damages as a way to protect the environmental quality, guide the soil management and the environmental recuperation of the ARW.