Potential Sea Level Rise for Coastal Counties in South Carolina

1
Potential Sea Level Rise forCoastal Counties in
South Carolina

• A Map Series Illustrating Future
• Sea Level Rise Scenarios

2
Introduction

• USC was asked to determine the potential effects
  of Sea Level Rise for the coastal counties of
  South Carolina.
• They used the best available Light Detection and
  Ranging (LIDAR) data to produce inundation maps.
  This data was provided by all of the counties,
  with the exception of Beaufort County. In this
  case, USC used a Digital Elevation Model (DEM) to
  perform the analysis. In Charleston County, only
  the City of Charleston provided LIDAR data, so
  only the urban area is mapped.
• The four scenarios were based on the
  Intergovernmental Panel on Climate Controls
  estimations in 2007 for potential sea level rise
  (lt0.6m) and a credible worst case scenario (1
  6m). The four sea level rise heights modeled
  were 0.6m, 1.0m, 3.0m, and 6.0m.

3
Jasper County
4
A sea level rise of 0.6 meters is estimated to
flood inland areas as much as 2.05m in some
areas. The majority of the flooding will be
minimal. The average flooding along the coastal
perimeter is estimated at 1.14m.
5
A sea level rise of 1.0 meter is estimated to
flood inland areas as much as 2.45m in some
areas. The flooding will occupy a greater area
in Jasper County however, the average flood
height is reduced to 0.75m.
6
A sea level rise of 3.0 meters is estimated to
affect a much larger portion of the county and
cover some areas of land with 4.45m of water.
The average flood height in the affected area is
1.86m.
7
A sea level rise of 6.0 meters is estimated to
cause as much as 7.45m of flooding along coastal
and riverine areas. The mean flood height will
be 2.9m and 68 of the area will have between 1.0
and 3.8m flooding.
8
Beaufort County
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Beaufort is a low-lying county, so any rise in
sea level will have a direct impact. A sea level
rise of 0.6 meters is estimated to cause 0.6m of
flooding in coastal and riverine areas. The mean
flood height will be 0.57m.
10
A sea level rise of 1.0 meter is estimated to
cover inland areas with as much as 1.0m of water.
The mean flood height will be approximately
0.83m in affected areas.
11
A sea level rise of 3.0 meters covers a
substantial portion of Beaufort County. It is
estimated to cover inland areas with 3.0m of
water with a mean flood height of 1.75m along
coastal and riverine areas.
12
A sea level rise of 6.0 meters would flood the
majority of Beaufort County with 6.0m of water.
The mean flood height is estimated to be 4.07m
and 68 of the affected areas will be under 2.38
to 5.7m of water.
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Colleton County
14
A sea level rise of 0.6 meters would flood
Colleton County with as much as 1.77m in some
coastal and riverine areas. The mean flood
height is estimated to be approximately 0.7m in
the affected areas.
15
A sea level rise of 1.0 meter would flood some
areas of Colleton County with approximately 2.17m
of water. The flooding will occupy a greater area
in the county however, the average flood height
is reduced to 0.63m.
16
A sea level rise of 3.0 meters would submerge
some areas of Colleton County with up to 4.17m of
water. The flooding will average 1.89m in the
affected areas.
17
A sea level rise of 6.0 meters in Colleton County
could cover the southern portion of the county
with up to 7.17m of water. The average flood
height would be approximately 3.68m .
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City of Charleston
19
A sea level rise of 0.6 meters in the City of
Charleston could submerge the downtown in 1.81m
of water. The average flood height is
approximately 0.89m.
20
A sea level rise of 1.0 meter in the City of
Charleston could cover areas along the coast and
rivers with 2.21m of water. The average flood
height is estimated to be 1.10m.
21
A sea level rise of 3.0 meters in the City of
Charleston could inundate low lying areas with up
to 4.21m of water. The estimated average flood
height is 2.19m.
22
A sea level rise of 6.0 meters in the City of
Charleston could flood the area with up to 7.21m
of water. The affected areas will experience an
average flood height of 4.16m.
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Georgetown County
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A sea level rise of 0.6 meters in Georgetown
County has the potential to cover areas with up
to 2.218m of water. Low-lying areas will have an
average flood height of 0.46m.
25
A sea level rise of 1.0 meter in Georgetown
County could flood coastal and riverine areas
with up to 2.618m of water. Impacted areas will
experience an average flood depth of 0.55m.
26
A sea level rise of 3.0 meters in Georgetown
County may inundate areas with up to 4.618m of
water. Affected regions will have an average
flood height of 2.05m.
27
A sea level rise of 6.0 meters in Georgetown
County could cover areas with up to 7.618m of
water. Inundated areas will experience an
average flood height of 3.36m.
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Horry County
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A sea level rise of 0.6 meters in Horry County
may cover areas with up to 1.002 m of water.
Inundated areas will only experience an average
flood height of 0.16m.
30
A sea level rise of 1.0 meter in Horry County
could cover areas with about 2.515m of water.
These affected areas along the coast and rivers
will have an average flood height of 0.43m.
31
A sea level rise of 3.0 meter in Horry County may
flood low-lying areas with as much as 4.515m of
water. The average flood height in the sea level
rise zones have an average flood height of 1.95m.
32
A sea level rise of 6.0 meters in Horry County
could cover areas with up to 11.675m of water.
This flood height is greater than other scenarios
because of extremely low lying areas that will be
inundated with this sea level rise.
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Conclusions County Analysis

• Jasper Areas with the greatest inundation
  heights in the 0.6m and 1.0m are located in the
  southern and eastern portions of the county.
  Fortunately, these are not heavily populated
  regions.
• Beaufort The low-lying characteristics of the
  county will cause any increase in the sea level
  to impact the county. Coastal and riverine areas
  will see the greatest impact, especially in the
  back bay areas. A sea level rise of 3.0 and 6.0
  meters would be detrimental to the county. The
  county could expect inundation of the a large
  portion of the roadways, hurricane evacuation
  routes, residential areas, and tourism related
  businesses.

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Conclusions County Analysis

• Colleton The areas most affected by sea level
  rise are the south eastern portions of the
  county. Fortunately, the most populated city in
  the county, Walterboro, is not in the expected
  inundated region.
• City of Charleston In Charleston, sea level
  rise of 0.6m will have immediate impacts in
  densely populated areas. Almost the entire city
  will be inundated with water in the 6.0m
  scenario. Land use planning and regulations
  should focus on the urban areas immediately
  affected by 0.6m and 1.0m sea level rise.

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Conclusions County Analysis

• Georgetown The areas most likely to be affected
  by sea level rise are located along the eastern
  and southern portions of the county. The back
  bays and low lying areas surrounding the rivers
  will be affected in 0.6m rise. The 1.0m scenario
  shows some flooding in the city of Georgetown.
  Populations at risk need to be identified and
  informed about the potential affects of sea level
  rise.
• Horry In Horry, inundation will occur along the
  southern border of the county, as well as along
  the Waccamaw River. The densely populated
  coastal areas will see some effects in the 3.0m
  and 6.0m scenarios, although not to the same
  degree as the other coastal counties.

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Conclusions Short Term

• Beaufort, Charleston, and Georgetown Counties
  will see the most land area affected by 0.6m and
  1.0m sea level rise.
• The City of Charleston has the largest population
  immediately affected by sea level rise, followed
  by Beaufort County.
• Initially, public education programs should be
  developed to target the populations immediately
  affected by sea level rise, primarily those in
  the urban areas. The public should understand
  the likely consequences that sea level rise will
  have on their property and the economy.

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Conclusions Long Term

• A large percentage of the population resides
  along the coast. The 3.0m and 6.0m scenarios
  would drastically impact the coast of South
  Carolina.
• Although these are worst case scenarios, the
  potential effects of sea level rise cannot be
  disregarded when we plan new development or
  mitigation strategies in these locations.
• Transportation networks, tourist areas, and
  densely populated residential areas are in the
  potential inundation zones. Land use planning
  and development regulations should be
  administered to prevent loss of property.

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Conclusions Long Term

• Long-term planning is necessary to prepare for
  and mitigate against sea level rise.
• The data found within this presentation will be
  incorporated into the South Carolina natural
  hazard and mitigation plans in the future,
  including
• Hurricane Plan
• Tsunami Plan
• State Hazard Mitigation Plan
• Local Hazard Mitigation Plans for coastal counties

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Reference

• 2007 Intergovernmental Panel on Climate Change
  (IPCC) Fourth Assessment Report
• http//www.ipcc.ch/ipccreports/tp-climate-change-w
  ater.htm

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Contact Information

• South Carolina Emergency Management Division
• Melissa L. Berry
• Risk Assessment Coordinator
• (o) 803-737-8856
• mberry_at_emd.sc.gov
• USC Hazards and Vulnerability Research Institute
• Christopher Emrich
• Project Manager
• (o) 803-777-1591
• EMRICH_at_mailbox.sc.edu