Risk analysis of San Marcos dam

San Marcos dam, built in 1998, is owned by the Junta de Extremadura (Regional Government). It is a concrete-faced rock-fill dam, 29 m high, located in the province of Cáceres (Spain). It has an ungated spillway and a bottom outlet. Its reservoir is used for water supply to the downstream population.

In recent years, the joints of the concrete face have suffered from some superficial deterioration produced by weather conditions. Due to the lack of leakage measurements, the effect of this deterioration in the dam imperviousness cannot be controlled.

In this context, a complete risk informed process was started by the owner, Junta de Extremadura, the consultant on conservation, maintenance and operating support for the dam, Paymacotas, and iPresas, providing the overall risk framework.

The risk informed process began with a visit to the dam and a review of the dam safety file, which includes Emergency Action Plan, Periodic Safety Reviews and Operating Rules. The process of visiting the dam and reviewing the available information is a fundamental requirement in order to provide sound engineering basis to risk analysis techniques.

A risk model was performed for San Marcos dam, and results were analysed to evaluate different risk reduction actions including the implementation of an Emergency Action Plan, rehabilitation of the concrete-face joints and improving monitoring systems.

This project represents the fourth one conducted for Regional Government of Extremadura in the recent years, after the analysis of El Horcajo, Membrío and Jaime Ozores dams.