FLOOD06826

• County: Statewide
• Basin: Statewide
• Title: National Economic Development Procedures Manual-Urban Flood Damage
• Date: 3/1/1988
• Prepared By: US Army Corps of Engineers
• Floodplain - Doc Type: Educational/Technical/Reference Information

')

of flood events, flow regime and damage for that reach, A single reach

may cover the entire developed area of a small community in which case it

is known as a "damage center." Sub-reaches and zones may be established

for the individual consideration of specific areas, particularly when on

opposite banks of the stream or when separated by bridges or dams which

appreciably affect local stage-discharge conditions.

Use, Reaches are the primary geographic unit for planning, Plans

are formulated with components that cover a series of reaches. The H & H

effects and subsequent benefits of a project are calculated for each

reach. Consequently it is extremely important that reach selection be a

joint effort by the project planner, the H&H engineers, and the economist,

The reaches, as defined by H&H considerations, are merely the

distance between cross sections, Stream size, slope, and uniformity of

the cross section shape are primary factors in determining the number of

cross sections, From the economists' point of view, reaches are

established primarily for the purposes of plan evaluation and display.
Economists use reaches to determine the smallest breakdown of damages and

benefits, Within each reach, breakdowns will be made of damages by land

use category and flood zone as defined by flood frequency.

Floodplain management schemes often call for a combination of

solutions, Solutions are based on changes, not only in hydraulic and

physical considerations, but also on land use and political

considerations, Reaches should be selected to help facilitate the

formulation process by allowing breaks where there are significant changes

in land use, changes in political subdivisions, and points where there may

be changes in the types of floodplain management solutions,

i

V-7