FLOOD05706

• County: Statewide
• Community: State of Colorado
• Basin: Statewide
• Title: DAMCAL - Damage Reach Stage-Damage Calculation - Users Manual
• Date: 2/1/1979
• Prepared For: State of Colorado
• Prepared By: Hydrologic Engineering Center
• Floodplain - Doc Type: Educational/Technical/Reference Information

Nonstructural Measures

The evaluation of nonstructural flood dama~e reduction measures requires

modification of the a~~re~ated elevation-dama~e function, although a pro-

posed measure may have little or no impact on the hydrolor,ic response of

the system (U.S. Army Corps of Engineers, 1977). The DAMCAL computer pro-

gram used to construct elevation-dama~e functions at damage reach index

locations for existing and alternative land use patterns (as described in

the preceding paragraphs) is also used in developing the damage functions

for nonstructural measures. The types of nonstructural alternatives for

which elevation-dama~e functions can be constructed are: 1) flood proofing

specified land use categories a r,iven number of feet above or below ground

or .first floor level (zero stage datum), 2) flood proofing specified land

use categories to a uniform flood protection level. 3) temporary protection

of structures and evacuation of contents in response to flood warning dis-

seminations, 4) permanent relocation of structures within flood prone areas,

and 5) regulatory policies restricting development in the flood plain.

Each of the nonstructural alternatives is evaluated by modifyin~ the appro-

priate land use category composite stage-damage function and/or the eleva-

tion-damage function of the grid cells affected.

Uniform Flood Proofing of a Land Use to a Specified Sta~e. The flood

proofing of selected land use categories to specified sta~es results in the

protection of ~ grid cells of the designated land use cate~ories to pre-

determined heights. The assessment of potential flood damage reduction

resulting from uniform flood proofing of this type is accomplished by direct-

ly modifyin~ the input composite stage-damage function (see Table 4-2) or

automatically (through the DAMCAL program) truncating the composite stage-

damage function at the appropriate level. Figure 4-6 illustrates and

describes the method used to perform the flood proofing assessment. As an

example, consider the evaluation of flood proofing future development only.

In a very simple land use alternative (used for purposes of clarity) the

grid cell classified as land use 6 (existing or base condition) is converted

4-17