Efeitos de obras hidráulicas na renovação das águas do Sistema Lagunar de Jacarepaguá e na balneabilidade das praias adjacentes ao canal da Joatinga

Abstract

Since the 1970s, the waters of the Jacarepaguá’s System have received large and growing loads of wastewater, rich in organic matter, from urban and industrial sources. This work evaluated, through computational modeling, the effects that hydraulic works in the lagoon system would induce in the local hydrodynamic circulation and in the quality of it waters and also of the adjacent beaches. These works are: clearing of channels and recovery of aquatic spaces through dredging and improvement of hydrodynamic conditions at the mouth of the Joatinga channel, modifying the jetties. The interventions considered propitiated the increase of the tide prism in the main channels of the system. They also allowed greater renewal of its waters, mainly to the lagoons of Jacarepaguá and Marapendi. The increase of water entering the system leads to a greater dilution and consequent decrease in the concentration of thermotolerant coliforms. The extension of the jetties improved the bathing conditions of the adjacent beaches.