Wake County Hazard Mitigation Plan - Adopted 10-21-2024

ANNEX H: TOWN OF KNIGHTDALE

H.1.3 FLOOD Table H.2 details the acreage of the Town of Knightdale by flood zone on the effective DFIRM. Per this assessment, over 5 percent of the Town of Knightdale falls within the mapped 1%-annual-chance floodplains. Table H.2 – FEMA Flood Hazard Areas, Town of Knightdale Flood Zone Acreage Percent of Total (%) Zone A 0.0 0.0 Zone AE 332.5 5.4 Zone X (500-year) 26.2 0.4 Zone X Unshaded 5,780.2 94.2 Total 6,138.9 -- Source: FEMA Effective DFIRM; Wake County GIS Figure H.3 reflects the effective mapped flood hazard zones for the Town of Knightdale, and Figure H.4 displays the depth of flooding estimated to occur in these areas during the 1%-annual-chance flood. Table H.3 provides building counts and values for critical facilities by flood zone in the Town of Knightdale. Table H.3 – Critical Facilities Exposed to Flooding, Town of Knightdale

Flood Zone

Critical Facility Count

Structure Value

AE

11

$96,884,156

X

100

$218,577,181

X, 0.2 PCT ANNUAL CHANCE FLOOD HAZARD

3

$30,921,975

Total

114

$346,383,312

Source: FEMA Effective DFIRM

To supplement the IRISK assessment of property at risk from the 1% annual chance flood event, the planning team evaluated flood risk using a level one analysis in FEMA’s Hazus software. Per this analysis, a 1% annual chance flood event would cause an estimated $3.9 million in building related damages. The results of the Hazus loss estimate are summarized in Table H.4. Table H.4 – HAZUS 100-Year Flood Results, Town of Knightdale

Total Buildings with Loss

Total Value (Building & Contents)

Estimated Building Damage

Estimated Content Loss $107,000

Estimated Total Damage

Occupancy Type

Loss Ratio

Agriculture

4

$316,000

$34,000

$141,000

45%

Commercial

12

$1,484,000

$95,000

$311,000

$406,000

27%

Educational

1

$56,000

$2,000

$15,000

$17,000

30%

Government

0

$0

$0

$0

$0

0%

Industrial

8

$230,000

$42,000

$139,000

$181,000

79%

Religious

3

$186,000

$11,000

$86,000

$97,000

52%

Residential

33

$3,983,000

$2,075,000

$1,077,000

$3,152,000

79%

Total

61

$6,255,000

$2,259,000

$1,735,000

$3,994,000

64%

Source: FEMA Natural Hazards Risk Assessment Program

Wake County, NC Multi-Jurisdictional Hazard Mitigation Plan

WSP June 2024 Page 479

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