Diagnóstico limnológico preliminar e do processo de assoreamento do reservatório do Parque Municipal Arthur Thomas (Londrina-PR)

Abstract

The silting process is one of the problems that has affected the lakes. Although this process is caused by natural causes, such as high winds and heavy rains, its occurrence has been more frequent, especially from the action of man, which has generated deforestation of the vegetation cover, waterproofing of the soils, discharges of rain gutters without due care and the accumulation of garbage, debris and debris in the lake bed. Its consequence has generated innumerable changes in its structure, from the reduction of water availability to the loss of biological diversity. The present work brings an investigation of the silting process in the lake of the Arthur Thomas Municipal Park. During the activities, certain in situ experiments were carried out, such as a bathymetric collection, sediment layer collection below the water column and limnological analysis of the water following some parameters stipulated by CONAMA Resolution 357/2005. The lake was divided into 14 linear transects spaced approximately 35 meters from each other, and for each transect data collection points were demarcated, totaling a total of 56 points. The results obtained on May 7 and 14, 2017 verified the degree of sedimentation of the lake, and it was understood that the areas with the lowest depths were located near the pluvial discharge pipes to the north of the lake and the largest volume of sediment accumulated as much to the north as in the central area of the lake. In general terms, it can be concluded that the lake is in fact an advanced sedimentation process, with sedimentary layers accumulated in its bed much higher than the water column. On the other hand, the sedimentation progression did not significantly interfere in the water quality for the analyzed parameters. In relation to the proposed objectives and the results obtained in the works carried out in the field, it is understood that environmental recovery measures are needed in order to reverse and minimize the silenced condition.