Coastal Planning after Katrina: Experiences on the Mississippi Gulf Coast

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Coastal Planning after Katrina Experiences on
the Mississippi Gulf Coast

• Tom Cathcart
• Pete Melby
• Jonathan Pote
• Mississippi State University
• Center for Sustainable Design

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• Mississippi Gulf Coast
• 110 km from Louisiana to Alabama
• Protected by the 4 barrier islands from
• storms and salt water incursion

AL
MS
Biloxi
MS
Gulfport
Pascagoula
Pass Christian
Bay St. Louis
LA
Waveland
Petite Bois Isl.
Ship Isl.
Horn Isl.
Cat Isl.
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These communities were devastated by Hurricane
Katrina August 29, 2005.
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• Hurricane Katrina
• Category 3 at landfall on Gulf Coast

Wind
Storm Surge
Category 3 Hurricane Category 5 Hurricane
111-130 mph 9-12 ft gt 155 mph
gt 18 ft
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• Hurricane Katrina
• Category 3 at landfall on Gulf Coast
• Category 5 one day earlier

Wind
Storm Surge
Category 3 Hurricane Category 5 Hurricane
111-130 mph 9-12 ft gt 155 mph
gt 18 ft
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• Hurricane Katrina
• Category 3 at landfall on Gulf Coast
• Category 5 one day earlier
• Storm surge 35 ft at barrier islands
• 25 28 ft on mainland
  shore

Wind
Storm Surge
Category 3 Hurricane Category 5 Hurricane
111-130 mph 9-12 ft gt 155 mph
gt 18 ft
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The combination of wind and storm surge was
intensely destructive.
Before
After
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Planning after Katrina?

• Of course, a lot has happened.

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Planning after Katrina?

• Of course, a lot has happened.

Homes with damage that exceeds 50 of fair market
value must be elevated above 100 yr flood level.
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Planning after Katrina?

• Of course, a lot has happened.

Homes with damage that exceeds 50 of fair market
value must be elevated above 100 yr flood
level. This was code before Katrina.
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Planning after Katrina?

• Of course, a lot has happened.

Homes with damage that exceeds 50 of fair market
value must be elevated above 100 yr flood
level. This was code before Katrina.
Homes with lt 50 damage can rebuild at original
elevation.
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Planning after Katrina?

• Of course, a lot has happened.

Homes with damage that exceeds 50 of fair market
value must be elevated above 100 yr flood
level. This was code before Katrina.
Homes with lt 50 damage can rebuild at original
elevation. But its not clear that these will be
insurable.
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Planning after Katrina?
But not much single-family building has actually
taken place. Uncertainty about regulations,
delays in grants, and insurance issues have made
most people cautious.
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Planning after Katrina?
New condominiums and plans for new condominiums
have proliferated on the waterfront (similar to
what happened on the more exposed Alabama
coast).
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Planning after Katrina?
New condominiums and plans for new condominiums
have proliferated on the waterfront (similar to
what happened on the more exposed Alabama
coast). But this is more battle than
planning.
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Four areas where new (and exciting) plans are in
place.
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Four areas where new (and exciting) plans are in
place.

• Adoption of SmartCode by 8 of the 11 effected
  communities.

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Four areas where new (and exciting) plans are in
place.

• Adoption of SmartCode by 8 of the 11 effected
  communities.
• Katrina Cottages

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Four areas where new (and exciting) plans are in
place.

• Adoption of SmartCode by 8 of the 11 effected
  communities.
• Katrina Cottages
• Beach stabilization using Bioengineering

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Four areas where new (and exciting) plans are in
place.

• Adoption of SmartCode by 8 of the 11 effected
  communities.
• Katrina Cottages
• Beach stabilization using Bioengineering
• Barrier island management

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SmartCode
By early October 2005, groups were beginning the
planning process.

• The Mississippi Renewal Forum charrette
• 200 local leaders and design professionals
  brainstormed for a week.

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By early October 2005, groups were beginning the
planning process.

• The Mississippi Renewal Forum charrette
• 200 local leaders and design professionals
  brainstormed for a week.
• Led by the Congress for the new Urbanism.

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By early October 2005, groups were beginning the
planning process.

• The Mississippi Renewal Forum charrette
• 200 local leaders and design professionals
  brainstormed for a week.
• Led by the Congress for the New Urbanism.
• Vision for renewed and rebuilt communities
  (SmartCode).

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SmartCode (from the City of Gulfport Smartcode,
Adopted 2/13/07)

• Neighborhoods and downtowns should be compact,
  pedestrian-oriented and mixed-use.
• Neighborhoods and downtowns should be the
  preferred pattern of development and that
  districts specializing in single-use should be
  the exception.
• Ordinary activities of daily living should occur
  within walking distance of most dwellings.
• Open spaces including parks, squares, and
  playgrounds should be distributed within
  Neighborhoods and urban center zones.
• Within Neighborhoods, a range of housing Types
  and price levels should be provided to
  accommodate diverse ages and incomes.
• 8 of 11 communities have adopted some form of
  SmartCode zoning.

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Katrina Cottages
Katrina Cottages An alternative to FEMA
trailers.
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• Katrina Cottages
• About the same price installed as
• FEMA trailers (100/sq ft).
• Designed to withstand winds of
• 130 mph.
• Designed for adding-on.

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The Katrina Cottage Project

• Funded by a 281 million federal grant and is
• administered by the Mississippi Emergency
• Management Agency.
• Mississippi will build three different types of
• cottages as part of the program.
• 4000-6000 units will be installed as
• replacements for FEMA trailers.
• All of these units are modular that can be
• converted into permanent dwellings.

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Highlight 3 Use of bioengineering for beach
stabilization
The Mobile District has coordinated efforts to
stabilize and protect the coast.
The 42 km beach is the longest manmade beach in
the world.
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Erosion on the beach takes 3 forms Wind blows
sand north off the beach across the adjacent
roadway.
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Storm water runoff carries sand south to the
water edge.
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Littoral currents carry the sand away.
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Erosion is exacerbated by mechanical grooming
(this has been the normal mode of beach
management). Mechanical raking fluffs surface
sand and compacts subsurface sand, which makes
wind and storm water erosion worse.
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• We applied the most basic bioengineering method
  planting with native (beach) vegetation.
• 3 acre experimental site.
• Topographical low point at the beginning of the
  project.

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Here is the site in 2002.
We planted 10 species of plants, trees, and
bushes.
A survey in 2002 showed 57 species.
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Beach profile before and after 2 tropical storms
in 2002.
More importantly, the site had gone from being a
local topographical low point to a local high
point. While the conventionally managed beach
lost sand, the experimental site gained
sand. Use of native plantings reduced all 3
forms of erosion and built the beach vertically.
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In 2006 we were asked to plant 1 acre at another
site to demonstrate the process. Since then, the
Corp of engineers has invited us to work with
them planting 120 acres (approximately 10 of the
entire 26 mile beach). This represents a
significant departure from previous beach
management.
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Highlight 4 Barrier island management
The satellite photo shown at the beginning of
this talk was actually pre-Katrina.
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The barrier islands were damaged by Katrina.
Cat and Ship Islands pre-Katrina (June, 2005)
Cat and Ship Islands post-Katrina (Sept., 2005)
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Horn and Petite Bois have both experienced
historical reductions in size.
Horn Island
Petite Bois Island
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Plans are currently underway to stabilize the
barrier islands using bioengineering.

• Katrina was followed by a drought.
• Tree roots remained in contact with high
  salinity water
• for an extended period.
• Only the most salt tolerant tree species (mainly
  live
• oaks) had high survival.

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Trees help to protect the mainland by dissipating
storm energy. Their roots literally hold the
islands together.
Section of Deer Island dominated by Live Oaks (a
salt tolerant oak species).
Section of Deer Island previously dominated by
less salt tolerant species (mainly long leaf
pine).
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• Reforesting is usually accomplished using
  seedlings.
• In a harsh setting, such as a beach or
• barrier island, un-irrigated plantings
• experience 80-90 mortality.
• Use of mature stock would result in
• faster replacement of lost trees.
• Use of more mature stock is
• prohibitively expensive in this
• environment where irrigation is not
• practical.

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Conventional wisdom plant trees with root balls
just below soil surface (roots need oxygen).
On our experimental site, we planted 50 trees
deep enough to reach the fresh water prism
beneath the sand ( 5 ft). High porosity of sand
allows oxygen transport to deep roots. 90
survival after 1 year.
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This fall we will try this on Deer Island to test
the viability of this approach for reforesting
barrier islands.
(A bit of hyperbole indulged in by our Alumni
Magazine)
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