ANNEX B: CITY OF RALEIGH
B.1.3 FLOOD Table B.3 details the acreage of the City of Raleigh’s total area by flood zone on the effective DFIRM. Per this assessment, about 7 percent of the city falls within the mapped 1%-annual-chance floodplains. Table B.3 – Flood Zone Acreage in the City of Raleigh Flood Zone Acreage Percent of Total (%) Zone A 0.0 0.0 Zone AE 7,133.7 7.4 Zone X (500-year) 170.8 0.2 Zone X Unshaded 89,547.3 92.5 Total 96,851.7 -- Source: FEMA Effective DFIRM; Wake County GIS Figure B.9 reflects the effective mapped flood hazard zones for the City of Raleigh, and Figure B.10 displays the depth of flooding estimated to occur in these areas during the 1%-annual-chance flood. Table B.4 provides building counts and values for critical facilities by flood zone in the City of Raleigh. Table B.4 – Critical Facilities Exposed to Flooding, City of Raleigh Flood Zone Critical Facility Count Structure Value AE 202 $7,547,048,869 X 1,301 $12,556,417,023 X, 0.2 PCT ANNUAL CHANCE FLOOD HAZARD 21 $143,066,942 Total 1,524 $20,246,532,834 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 $306.2 million in building related damages. The results of the Hazus loss estimate are summarized in Table B.5. Table B.5 – HAZUS 100-Year Flood Results, City of Raleigh
Total Buildings with Loss
Total Value (Building & Contents)
Estimated Building Damage
Occupancy Type
Estimated Content Loss
Estimated Total Damage
Loss Ratio
Agriculture
18
$1,689,000
$162,000
$564,000
$726,000
43%
Commercial
264
$378,060,000
$33,329,000
$96,027,000
$129,356,000
34%
Educational
33
$25,571,000
$977,000
$6,296,000
$7,273,000
28%
Government
28
$49,531,000
$856,000
$5,108,000
$5,964,000
12%
Industrial
126
$26,814,000
$6,720,000
$15,176,000
$21,896,000
82%
Religious
47
$13,272,000
$723,000
$5,067,000
$5,790,000
44%
Residential
619
$172,650,000
$86,916,000
$48,335,000
$135,251,000
78%
Total
1,135
$667,587,000
$129,683,000
$176,573,000
$306,256,000
46%
Source: FEMA Natural Hazards Risk Assessment Program
Wake County, NC Multi-Jurisdictional Hazard Mitigation Plan
WSP June 2024 Page 386
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