Decision analysis and risk analysis of multiple dam removals: Optimizing tradeoffs among dam failure risk, removal cost, and ecosystem benefit

Decisions on dam removal or retention are complex and sometimes controversial because of economic and ecological tradeoffs, diverse stakeholders, as well as public safety concerns. This dissertation combines mathematical optimization, ecological models, and a public survey to analyze the benefits and costs of removing aging and deteriorating U.S. dams on tributaries to Lake Erie, where dam removal is considered as not only a viable habitat and ecosystem restoration tool, but also an effective management option to improve public safety.;Using multiobjective analysis, the main purpose of this dissertation is to analyze the cost-effectiveness of single or multiple dam removals by examining the interactions between dam removal actions and system responses and quantifying impacts upon social, ecological, and economic objectives of importance to decision managers and stakeholders. More specifically, this research develops and integrates multidisciplinary models for optimal selection of dams to be removed by considering three fundamental objectives: financial cost, lake-wide ecosystem health, and public safety.;Three multiobjective analysis models have been developed, each focusing on different aspect of the problems and tradeoffs and each with a case study in the Lake Erie basin. In particular, the first case study takes account of all possible financial costs of removing (;Overall, findings from three case studies communicate the general nature of the tradeoffs and complex interactions among dam removal related expenditures and risk management options, habitat and ecosystem restorations, and fish community dynamics; and more importantly, show the effect of alternative human value judgments on making the science-informed decisions to remove aging and unsafe U.S. dams.