Each of the four methodologies developed in this report contributes an important dimension to risk-based evaluation of systems for flood damage reduction-which is incomplete without accounting for both structural and nonstructural measures. The unifying theme of these results is that the design and evaluation of structural and nonstructural measures for flood mitigation, including flood warning and preparedness systems, is an integrative, holistic process that eventually must build on an understanding of the contribution of each type of measure to the performance of the overall system. Furthermore, the design of flood mitigation is tied to multiple objectives of minimizing cost and risk and maximizing performance. Consideration of the risk of extreme events is an essential element in the evaluation of design tradeoffs. The four methodologies developed here for the modeling and evaluation of flood warning and preparedness systems are: (1) Integration of structural measures and flood warning/preparedness systems; (2) Multiobjective decision-tree analysis; (3) Performance characteristics of a flood warning system; and (4) Selection of optimal flood warning threshold. The assumptions, main functions, and limitations of the four methodologies are summarized in Table 1.