Assessing Decision Consistency in Consequence-Based Dam Safety Classification Under Limited-Data Conditions

Consequence-based dam classification is central to dam safety management, yet screening and regulatory approaches often rely on proxy measures of downstream exposure without explicitly considering hydraulic severity or wave arrival time. This limits discriminatory capacity, particularly where detailed exposure, demographic, evacuation, and asset-level consequence data are unavailable. This study introduces the Assessment of Technical Simplified Consequences (AT-SAC), a screening-oriented framework using widely available geospatial data. AT-SAC integrates five dimensions—Population at Risk (PAR), Wave Arrival Time at Residences (WTR), critical infrastructure (INF), environmentally sensitive areas (ESA), and socioeconomic disruption (SD)—within hydraulically conditioned consequence zones. The internal behavior of the classification structure was evaluated across 592 logically admissible consequence combinations under the baseline and two alternative weighting schemes, showing limited sensitivity to the relative weighting of the two life-safety criteria. Applied to four dams in northeastern Brazil with contrasting structural and downstream exposure conditions, AT-SAC differentiated the cases across four consequence tiers, from Significant to Extreme. Compared with two Brazilian regulatory classification systems, AT-SAC provided greater differentiation by separating exposure magnitude from response-related constraints, supporting transparent consequence-based prioritization under limited-data conditions.