Acueducto Metropolitano, tramo embalse el Llano-Río Navarro (Costa Rica): un sitio bajo amenza

Abstract

The Metropolitano aqueduct is a very important engineering-public work for the population of the Valle Central and at the same time a geologically vulnerable place. At least live landslides, on soil and rock, have important size, some of then with serious consequences and affecting the water pipe stability. 'These phenomenons have been partially controlled by the technical team of Instituto Nacional de Acueductos y Alcantarillado. On the other hand, combined with deficiently constructive practice ignoring the geologic-structural settings, all the debris and materials removed during construction were deposited on totally non stable sectors (very steep slopes) and during the rainy season were locally washed down by the runoff, menacing Orosi town because of debris avalanches. Therefore, there were identificated some seismic sources associated neotectonic faulting and capable for triggering natural disasters with serious consequences the national economy. One of these sources is the responsible for the 1910 and 1951 earthquakes, events the destroyed Cartago city and Orosi town respectively. Finally, a rupture of the water pipe could originate a mud and rocks avalanche, which in terms of minutes could directly fall upon Orosi population.