FLOOD07643

• County: Statewide
• Basin: Statewide
• Title: Physical and Economic Feasibility of Nonstructural Flood Plain Management Measures
• Date: 3/1/1978
• Prepared For: US
• Prepared By: US Army Corps of Engineers
• Floodplain - Doc Type: Educational/Technical/Reference Information

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PREFACE

This report presents the findings of an investigation into the physical and economic feasibility
of eleven nonstructural flood plain management measures. These measures were selected from
a larger number of possibilities principally because they appeared to be the ones being used
most frequently and limited time and budget necessitated a reduced number. As a result of a
detailed examination of each measure, some general conclusions and observations regarding
nonstructural measures were reached. These are discussed in Chapters 1 and 2 under concept
and characteristics and should serve as an introduction to the subject and to some of the related
problems and questions, Chapters 3 through 13 examine each nonstructural measure in detail.
Each Chapter contains a description and illustration of the measure, a discussion of its physical
feasibility, an engineer's cost estimate, an evaluation of its economic feasibility, a summary of
advantages and disadvantages, and a list of important references, In some cases it was
impractical to estimate.cost. In these cases only the cost items were identified. The evaluation of
economic feasibility was made by comparing estimated costs with damage reduced. Cost
estimates included only essential items in an attempt to estimate a minimum cost. Damage
reduced was computed using 1970 Federal Insurance Administration depth-damage and 1974
elevation-frequency data. This gave a maximum damage reduction estimate. Using minimum
cost and maximum damage, an "optimistic" estimate of economic feasibility was obtained.
Where it was impractical to make a quantitative evaluation of feasibility, some general
observations are presented.

Appendix A contains the detailed damage analyses used in establishing economic feasibility.
There are numerous variables to consider in estimating expected annual flood damage and
Appendix A presents findings on the sensitivity of damage estimates to each of these variables.
These data should be useful to any person desiring to understand or estimate the significance of
a particular variable on flood damage estimates. It should be pointed out, however, that the
computed damage values are based upon generalized elevation - frequency and depth -
percent damage data and should not be used in estimating damage where site specific data are
available. Appendix B contains a summary of the engineer's cost estimates for selected
measures. Appendix C contains information which was developed during the investigation and
which it was thought would be useful to anyone investigating forecast, warning, and evacuation
as a nonstructural alternative. Appendix D contains similar information on construction
materials and methods to reduce damage. A bibliography of papers, reports, texts and other
literature collected during the study is cited alphabetically in Appendix E.