Physical modeling of diversion works of the Baker and Pascua rivers

Abstract

The Aysén Hydroelectric Project considers the construction of 5 dams in the Baker and Pascua rivers in the southernmost part of Chile. Both rivers in the project area are characterized by narrow valleys, high slopes (> 1% – 2%) and large streamflows that range between 600 and 800 m3/s during the low flow season. In order to study the diversion of the rivers, two scaled physical hydraulic models (1:70 for the Baker river and 1:60 for the Pascua river) were built at the Hydraulic Laboratory of the Pontificia Universidad Católica de Chile to test different methods for cofferdam construction. In this study, we investigate the use of a combination of precast concrete elements such as cubes, tetracubes and tetrapods, along with the use of graduated soil and rock fills to produce a semi-impervious cofferdam. This report presents a summary of the experimental work conducted in the physical models, focusing on the final adopted solution which considers the use of 30 t tetrapods and graduated soil and rock fills to achieve impermeability of the cofferdams.