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

ANNEX G: TOWN OF HOLLY SPRINGS

G.1.3 FLOOD Table G.2 details the acreage of the Town of Holly Springs by flood zone on the effective DFIRM. Per this assessment, over 5 percent of Holly Springs falls within the mapped 1%-annual-chance floodplains. Table G.2 – Flood Zone Acreage in the Town of Holly Springs Flood Zone Acreage Percent of Total (%) Zone A 0.0 0.0 Zone AE 700 5.6 Zone X (500-year) 0.2 0.001 Zone X Unshaded 11,782.3 94.4 Total 12,482.6 -- Source: FEMA Effective DFIRM; Wake County GIS Figure G.3 reflects the effective mapped flood hazard zones for the Town of Holly Springs, and Table G.4 displays the depth of flooding estimated to occur in these areas during the 1%-annual-chance flood. Table G.3 provides building counts and values for critical facilities by flood zone in the Town of Holly Springs. Table G.3 – Critical Facilities Exposed to Flooding, Town of Holly Springs Flood Zone Critical Facility Count Structure Value AE 13 $536,998,394 X 60 $160,519,478 X, 0.2 PCT ANNUAL CHANCE FLOOD HAZARD 1 $0 Total 74 $697,517,872 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 $5.7 million in building related damages. The results of the Hazus loss estimate are summarized in Table G.4. Table G.4 – HAZUS 100-Year Flood Results, Town of Holly Springs

Total Buildings with Loss

Total Value (Building & Contents)

Estimated Building Damage

Estimated Content Loss

Estimated Total Damage

Occupancy Type

Loss Ratio

Agriculture

0

$0

$0

$0

$0

0%

Commercial

6

$360,000

$16,000

$67,000

$83,000

23%

Educational

1

$156,000

$6,000

$38,000

$44,000

28%

Government

0

$0

$0

$0

$0

0%

Industrial

4

$1,318,000

$331,000

$812,000

$1,143,000

87%

Religious

1

$19,000

$1,000

$8,000

$9,000

47%

Residential

36

$5,486,000

$2,929,000

$1,551,000

$4,480,000

82%

Total

48

$7,339,000

$3,283,000

$2,476,000

$5,759,000

78%

Source: FEMA Natural Hazards Risk Assessment Program

Wake County, NC Multi-Jurisdictional Hazard Mitigation Plan

WSP June 2024 Page 467

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