WATER QUALITY EVALUATION IN MICROWATERSHED OF THE GAVANHERY AND LAMBARI STREAMS (GETULINA, SÃO PAULO STATE, BRAZIL)

Abstract

The work had as objective to monitoring and analyzing the water quality of the microwatershed of Gavanhery and Lambari streams, in Getulina town, Sao Paulo State, in the period between may and october of 2007, and its degradation stage in association to the utilization of the surrounding area. Monthly, water samples were collected in seven points of this microwatershed, and some of its physical, chemical and biological parameters were analyzed that allowed to calculate the WQI - Water Quality Index. Gavanhery an Lambari streams were both located in the periphery of the municipal district, and receive waters from clandestine domestic sewers and from superficial pluvial waters. The WQI results, in addition to observations in loco, also made possible to evaluate the water quality and check the actual degradation stage of this hidrographic basin, manifested by erosion, the ciliary forest nothingness, increase on the number of factors for fertilizers (phosphorus and nitrogen) and the increase of the concentration levels of the fecal coliforms and total, in some analyzed points. Went verifyd that the pollution in Gavanhery and Lambari streams was kept in high level in some periods of the year, so its numbers are lower than a Class II level river (at points 2, 3 but especially at Point “5”), located at the urban environment, where the water quality is considered “Bad”. For points 1, 3, 6 and 7 the water quality is considered “Acceptable”, requesting correction measures and mitigation in the most affected places, and a maintainable handling that allows for the microbasin conservation.