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County Builds Coastal Erosion Resilience with 2,250 meters of Oyster Reefs

Mobile County

Mobile County, AL

Mobile County built shoreline erosion resilience by building 2,250 meters of submerged breakwater oyster reefs as part of a living shoreline project, allowing for natural habitat elements to reduce erosion while maintaining a healthy habitat for wildlife.

Topics Covered

Coastal & Tidal Flooding
Hurricanes & Severe Storms
Sea Level Rise

Cost

Initial: 14 Million USD

Funding

Public Private Partnership

Project Status

Operational since 2008

Problem Addressed

Shoreline erosion is a significant problem for Alabama’s coastal communities.

Each year rising sea levels push back the coastline, aided by waves, wind, and natural disasters.

Property owners and communities have historically “armored” the shoreline with hard structures, such as bulkheads, to protect waterfront coastal property from erosion. Although effective in strengthening the shoreline against erosion, these hard structures can damage the environment through decreased water quality, habitat loss, and loss of public water access. The high proportion of “shoreline armoring” has even increased Alabama’s shoreline erosion rates, as they can fail if too much sediment is scooped away from the support structure by waves.

Other states have used an alternative “living shoreline” solution to reduce erosion without damaging environmental impacts. Living shorelines also allow waterfront access needed for loading boats and fishing.

In July 2009, the National Oceanic and Atmospheric Administration (NOAA) awarded a 2-year grant through the American Recovery and Reinvestment Act (ARRA) to a collaboration led by The Nature Conservancy for a Mobile Bay Coastal Restoration project to restore coastal habitats in south Mobile County, Alabama.

Solutions Used

Mobile County used sustainable oyster reefs to build living shorelines along a 1.5 mile stretch of eroding shoreline.

The Nature Conservancy, in partnership with The Dauphin Island Sea Lab, Mobile County, and other state-run organizations, used the grant to build living shoreline options along two stretches of eroding shoreline totaling about 1.5 miles in Portersville Bay and Mobile Bay.

The ideal living shoreline, rather than creating a barrier between land and the water, allows for natural habitat elements to reduce erosion while maintaining a healthy habitat for wildlife. One of the most common methods is the use of sustainable oyster reefs as breakwaters. The addition of oyster shells acts as a natural breakwater, absorbing wave energy before it hits the shore.

To promote the growth of oyster reefs on the Mobile Bay shoreline, the project team carried out three separate tasks. First, the team bagged enough oyster shells to create 750 linear meters worth of breakwater. Secondly, marine-friendly concrete was used to create 3,168 Reef Balls whose many nooks and crannies will play host to oyster larvae, and whose installation will stop erosion due to high wave energy. The final step was constructing 492 REEFBLKsm vertical oyster reef cages,

The sustainable project created about 2,250 meters of submerged breakwater reefs that will absorb the impact of wave energy from storms and boat activity, protecting the shoreline from erosion. In addition, the submerged oysters filter impurities from water, enhancing the viability of sea gross meadows and salt marshes for juvenile fish and invertebrates.

Outcomes

1

Created 2,250 meters of submerged breakwater reefs to protect the shoreline from erosion while enhancing the habitat for fish, birds, and invertebrates

2

The oyster reefs are sustainably refreshed by an Alabama Coastal Foundation program which recycles empty oyster shells from local restaurants into the oyster reefs.

3

The success of the project should inspire future living shoreline projects, particularly on private land

4

The use of a living shoreline eliminated the environmental damage associated with armored shorelines, such as decreased water quality, habitat loss, and loss of public water access.

Something Unique

This project spawned an oyster shell recycling program organized by The Alabama Coastal Foundation and funded with grants from the National Fish and Wildlife Foundation's Gulf Environmental Benefit Fund, which collects emptied oyster shells from local restaurants for redistribution into the oyster reefs.

Who Should Consider

Communities looking for environmentally-friendly methods to build coastal erosion resilience, while maintaining a healthy habitat for wildlife.

Last Updated

Mar 18th, 2022
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