SILTATION AND EROSION PROCESSES ON A TRIBUTARY OF LAKE ITAIPU, PARANÁ STATE, BRAZIL

Cristiano Poleto

Federal University of Technology – Paraná (UTFPR) Toledo, Brazil

Abstract

It is known that sediments in the river have their origin from different sources. Therefore, the proportion that each source contributes to the mix varies over time and space, as a result of erosion processes that are ongoing in the basin of contribution. Within this context, both in human actions in urban and rural watersheds generate different rates of sediment production, but mainly with different characteristics or quality. Thus, the fluvial sedimentology should have a broad character within the study area and check all the possible influences of land use and soil. Hydrosedimentological processes are complex and include a disaggregation ("erosion" in the strict definition), transport, sedimentation, consolidation of sediments. Therefore, it is necessary more detailed studies of sediments and their interactions with the environment, considering it as a topic of interest to economic, social and ecological needs of a sustainable management, where they articulate an understanding of the physical and chemical properties of sediments with ecological and hydrological information of the water bodies receiver on a regional scale and thus evaluate the possible scenarios of pollution of water resources. This information will support in decision-making processes for managing the watershed and its water resources. Thus, this research is conducting a survey of sensitive areas to erode and the influence of a newly installed hydropower in a tributary of Lake Itaipu. Could notice that the removal of riparian vegetation is accelerating the erosion processes at various points of the river, but the plantation system used in the rural area, without revolving of soil, has reduced the sediment load produced by this source. However, the retention of much of the coarse sediments by the new dam is creating an imbalance between the amount of sediment transported after the hydroelectric and sediment transport capacity of flow from that. The result is the generation of erosion within the river channel in this part and more sediments are arriving to Lake Itaipu.

Keywords: sediments, water resources management, siltation, erosion

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