Análisis del territorio fluvial, el caudal ecológico y el riesgo asociado a la dinámica del rio Negro en General Roca y alrededores.

Abstract

Currently, there are few studies focused on geomorphological changes or fluvial dynamics due to the different hydroelectric complexes and dams installed in the basins of the Neuquén and Limay rivers. So, in order to understand the changes in the Negro River, this Final Degree Project addresses this issue through different studies and methodologies in the vicinity of the city of General Roca. First, the Montana method is used as an approximation to estimate the Environmental Flows and compare them with the natural conditions prior to the establishment of the dams. Then, hydrogeomorphological changes in response to the establishment of dams were analyzed. Based on known fluvial parameters, it was possible to characterize the changes in the hydrological regime and sedimentary transport that the dams are exerting on the system. For this, changes in the fluvial sinuosity, and in the areal distribution of the riparian vegetation were quantified from the 1960s to 2019. Also, a method for monitoring floods through satellite Synthetic Aperture Radar (acronym SAR) is evaluated. Finally, a study that consisted of mapping a River Territory was developed. It comprised framing the area where the river and ecological dynamism is developed (lateral movements, the extent of its regular floods, among others); and separate it from the developable areas. With the aim of protecting not only the riparian ecological systems from urbanizations and structural changes caused by dams, but also to protect urbanizations from the ecological alterations and dynamism of the river. This series of analyzes and methodologies has made it possible to establish that the Negro River has a degrading flow, but still with healthy conditions. The general trend of its flows frames a continuous and sustained degradation. This decrease in the flow rates reduces the sedimentary transport capacity, promoting not only the establishment of islands and bars, but also the advance of invasive vegetation, promoting a decrease in the lateral dynamics of the river.