ÍNDICE DE SEGURANÇA SEMI-QUANTITATIVO APLICADO À BARRAGEM DO CHASQUEIRO – ARROIO GRANDE/RS/BRASIL

Abstract

The safety of earth dams is a central issue in geotechnical engineering due to the aging of structures, the increase in potential consequences associated with failures, and the need for objective methods to support dam management. In this context, this study applies a Dam Safety Index (DSI) to the Chasqueiro Dam, located in the municipality of Arroio Grande, southern Brazil, aiming to evaluate, in a semi-quantitative manner, its current safety conditions and to critically discuss the applicability of the method. The analysis was based on field inspections, available technical records, and information derived from recent studies. The obtained value (DSI = 55.91) classifies the dam as “Deficient” according to the index criteria. However, this result is strongly influenced by parameters associated with design characteristics and territorial context, especially Spillway Type and Dam Importance, rather than by the identification of active critical structural failures. Sensitivity simulations indicated that even under idealized global management conditions, the DSI remains below the “Adequate Safety” threshold, highlighting the conservative nature of the method. It is concluded that the DSI is a useful screening and decision-support tool, and its results should be interpreted in an integrated manner with technical inspections and monitoring programs, avoiding isolated interpretations of the dam’s actual safety condition.