Aguas subterraneas na Baixada Campista (Campos dos Goytacazes, RJ): geometria, qualidade e dinamica no aquifero quaternario deltaico

AUTOR(ES)
DATA DE PUBLICAÇÃO

2003

RESUMO

Located in Campos dos Goytacazes municipality, northern region of Rio de Janeiro State, comprising approximately 440km2 of the coastal plain (continental portion of Campos Sedimentary Basin), the area under study comprises the most important districts of the municipality - Goytacazes, Tocos, Donana e Ururaí - such as its headquarters. The Campos s slope has plenty ofbrooks and artificial channels, in addition to greater bodies such as Paraíba do Sul river to the north and Feia lagoon to the south. However, the climatic conditions engenders a regional hydric deficit. That is an agricultura I land traditionally based on the sugar cane monoculture and more recently its economy has depended on gas and oil production royalties. The object of study is the Deltaic Quaternary Aquifer, which was formed by residual soils, sands, gravels, clays and silts arising from integration of sea, river-sea, river and river-Iake accumulation environrnents; a typical deltaic sedimentation on an area subject to tectonic movement and sea leveI transgressions and regressions. Nowadays, the sedimentary package which spreads from NW to SE can reach until120 meters in thickness. That is an unconfmed aquifer fed by Paraíba do Sul ri ver, with discharge are a on Feia lagoon, and in an almost homogeneous behaviour, excepting from the anomalous strip of the Paraíba do Sul paleochannel. All the wells drilled on this preferential strip gained excellent discharge output, which reached until 300m3fh (discharge output very much above the ones found on the remaining area). The specific capacity varies from 0,01 to 139,24m3/h/m, the transmissivity values vary from 0,678 to 9023,00m2/dia, and the hydraulic conductivity values vary from 0,0 1 2crn/s to which can exceed 0,16crn/s. As it is a big alcohol producer, there is a suspicion that bad agricultural practices engender or increase quality problems on that area. Indexes of ions such as potassium, iron and sodium are above the lirnits by the brazilian health ministry, in all over the area of study. The total nitrogen values are above the limits just under urban concentration areas. Analyses of little deep sample collections (approximately 3 meters) were classified with regards to agriculture use and medium to high salinity and powerless sodium waters. The tropical clirnate (hot and dry throughout the year), together with agricultural processes and marine influence, increased groundwater and soil saltiness, in general, the southern / south-eastern region of the area of study, which presents the worst saltiness situation from the qualitative point of view. Following the groundwater variation tendency on the discharge area, the studied indexes are subjected to changes of con~entrations in the course of the water cycle.

ASSUNTO(S)

recursos hidricos aguas subterraneas aquiferos

ACESSO AO ARTIGO

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