Dam break risk assessment in Baker Valley (Chilean Patagonia)

Abstract

An hydroelectric project was proposed by HidroAysen Company in the Aysen Region of Chilean Patagonia. It consisted of the installation of five hydroelectric power stations, two on Rio Baker and three on Rio Pascua, with an average annual energy production of 18,430 GWH. The Environmental Impact Assessment (EIA) presented by HidroAysen lacked of a dam failure impact assessment, crucial to prevent or minimize the impact of unexpected flooding caused by a dam failure. A dam break risk assessment was performed for the so called Baker 2, a proposed concrete gravitational dam located on the Rio Baker, upstream the small community of Caleta Tortel, an area of concern for potential flooding. Using ORSA Code, software developed by a research collaboration between the University of Pavia and the University of Rome - La Sapienza (Italy), a computational model was performed to simulate the flood wave propagation associated with a dam break failure scenario. The areas subject to flooding were mapped on the digital elevation model (DEM) of the surface topography.