Abstract

Southern Chile is a place that has many rivers product of the lot of rain falling during most of the year and the melting of the Andes Mountains, this allows the construction of hydroelectric plants to power electric energy to the country. However, to make an assessment of the environmental impact caused by intervening watercourses is required to measure the flow of the river at various points along the way to determine if the construction of the hydroelectric plant on the river is able to maintain a water flow that allows the sustainability and biodiversity of the ecosystem. In the austral region of Chile flow rate are evaluated in high and medium rivers flow, both are in inaccessible area where cannot be made mechanical measurement equipment. By foregoing is that the water flow measurements are made using the techniques of fluorescent tracer dilution and used Rhodamine WT. For measurements at high flow, the method of injection punctual is selected, due to the operating conditions of the site under study; flow rates around 100 m3/sec, few accesses for installation of measuring it is necessary the injection of the tracer from a helicopter. The tracer is injected into the river upstream of site at a distance conducive a long good mix. The passage of the tracer is registered on the site of measurement by deriving water from the river. In river with medium flow, continuous injection method is selected due to the operating conditions of the site, flow rate less than 10 m3/sec and easier access to the riverbanks. It is possible to install measurement stations and injection at constant flow in appropriate places. The values ​​obtained for the river with high flow varied between 70 and 150 m3/sec and for medium river flow between 1 and 10 m3 /sec. These values ​​allow decisions to implement the projects under study of hydroelectric power station.