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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TABLE 3-1

ESTIMATED COST FOR TEMPORARY CLOSURES'

Item
Flood Shields (3 - 3'x3' aluminum, installed)
Sewer Gate Valve

Estimated Cost

Total First Cost

Annual Cost'

Annual Cost as Percentage
of Structure Value

;

$ 980.
300.
$1,280.
$ 102.
.34

;

;

1 Estimated for a $30,000, 1,600 square foot structure with front, rear, and side entrances. Closure to
3 feet above first floor. Costs include 25 percent for contractor's bonds, overhead, profit and
engineering.

2 Amortized at 7 percent for 30 years.

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Other cost items sometimes required to insure watertightness are,

. Sealant for exterior walls including sand blasting, caulking cracks, applying sealant, and
repainting.

. Wall construction around a patio to protect sliding glass doors.

. Fireplace c1eanout seal.

. Flood shields for additional doors or windows.

. Inspection to insure watertightness over the life of the structure.

More and larger openings or additional protection (sealants, etc.) will increase the base cost
shown in Table 3-1.

Economic Feasibility
When flood water is prevented from entering a structure, damage is reduced up to the design
level. When a flood exceeds the protection level damage occurs as it normally would without
protection and immediate inundation to that level is normally assumed. Damage reduced
includes damage to contents and structure interior. Damage to the structure exterior and the
site still remain. Figures 3-2 and 3-3 show expected annual damage reduced by protecting a
single or two story structure without basement to 3 feet above the first floor. The values include
a reduction in damage to the structure exterior, but this is small. Details of this analysis are
discussed in Appendix A.

These data show damage reduced varies from over 14 percent to approximately 0.25 percent
of the structure value depending upon the type structure, flood hazard factor, and event at the
first floor. This compares with an estimated cost of 0.34 percent discussed in the previous
section. This cost is shown in the Figures for comparison with damage reduced. For a single
story, no basement struct.ure (Figure 3-2) damage reduced exceeds costs for all conditions

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