Book excerpt: The goals of nonstructural flood-control planning are formulation, evaluation, selection, and implementation of a practicable management plan that provides optimal protection from the adverse effects of flooding. Many alternative flood-control measures can be dismissed by the water resources planner on the basis of judgement, but a substantial number will require detailed analysis before a suitable plan can be selected. This analysis is an iterative process, requiring input from the planar at each step. Software developed at the Hydrologic Engineering Center (HEC) allows efficient data storage in a structure-oriented data bank and provides for selective retrieval and manipulation of the data from an interactive terminal. Thus the planner is able to propose nonstructural measures and to evaluate rapidly the economic and technical feasibility of those measures in a iterative scheme that allows the required input from the planner. An application of the interactive plan evaluation software is presented. Steps in creating the data bank are defined, and use of the software for subsequent accessing and manipulating the data for plan evaluation is discussed. (Author).