Bio-Engineered Oyster Reef Demonstration (LA-08)

LA-08

Purpose:

The purpose of this project is to test a new, bio-engineered, product to address rapid shoreline retreat and wetland loss along the Gulf of Mexico Shoreline in areas with soils of low load bearing capacity. For example, at Rockefeller Refuge, the direct Gulf of Mexico frontage and extremely low soil load bearing capacity (250-330psf), coupled with an average shoreline retreat of 30.9 ft/yr, present unique engineering challenges with a subsequent direct loss of emergent saline marsh.

Restoration Strategy:

The goal of this demonstration project is to evaluate the proposed technique as a cost effective technique for protecting areas of Coastal Louisiana’s Gulf of Mexico Shoreline with poor load bearing capacities.The demonstration project would consist of an Oysterbreak, approximately 1000′ long. The Oysterbreak is a light-weight, modular shore protection device that uses accumulating biomass (an oyster reef) to dissipate wave energy. The bio-engineered structure is designed to grow rapidly into an open structured oyster reef utilizing specifically designed structural components with spat attractant (agricultural byproducts) and enhanced nutrient conditions conducive to rapid oyster growth.

Required Monitoring: [1]

  • Topographic and bathymetric surveys (elevation, water levels)
  • Ground-level photography
  • Aerial photography
  • Wave attenuation (wave energy effects)
  • Oyster and Water quality monitoring

The Oysterbreak is constructed by placing modular units into an open interlocked configuration. The units are sized to be stable under storm wave conditions. The height and width of the Oysterbreak are designed to achieve a moderate initial wave energy reduction. As successive generations of encrusting organisms settle on the Oysterbreak, the structure’s ability to dissipate wave energy increases.

Location:

The project is located along the Rockefeller Wildlife Refuge Gulf of Mexico shoreline west of Joseph Harbor canal in Cameron Parish, Louisiana.

pic_LA_08

Project Effectiveness: [2]

The oysterbreaks are providing habitat for oyster settlement and the top layers of rings should be the most likely to support oyster colonies. Recommended improvements include:

  • Types of cement applications
  • Lessening the space available for coastal erosion (the gap between coast and oysterbreaks needs to reduce to prevent further erosion).
  • Crest elevation between the oysterbreaks performed well in wave attenuation and shoreline erosion
  • Increase the height of the structure to improve wave breaking potential

aerial_rings

Progress to Date:

The cooperative agreement between the National Marine Fisheries Service and the Louisiana Department of Natural Resources has been executed. Construction was finalized in February 2012. This project is on Priority Project List (PPL) 17.

More Information on this Project:

Further Websites Regarding Oyster Reef Restoration:

 

 

Work Cited:

[1] McGinnis and Pontiff. (pages 4-6) LA-08 2012 Operations, Maintenance, and Monitoring Plan, 30 April 2018, https://www.lacoast.gov/reports/project/4224379~1.pdf

[2] McGinnis and Pontiff. (page 22) 2014 Operations, Maintenance, and Monitoring Report for Bioengineered Oyster Reef Demonstration Project (LA-08)

 

 

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Wetland Wonders at Ocean Commotion

Can you figure out the mystery coastal item based on the following clues? It contains a bivalve that a) makes pearls, b) is a filter feeder, and c) we eat here in Louisiana.

Over 1600 elementary and middle school students had the chance to read those clues at LSU Sea Grant’s Ocean Commotion on October 24 in Baton Rouge. Students, teachers, and chaperones then reached their hands into a box and tried to identify the item (oyster shell) they were holding. Other mystery items included a nutria pelt, cypress knees, an apple snail shell, and a magnolia seed pod- all from plants and animals that call Louisiana’s coastal wetlands home.

2017 marks the 20th Anniversary of Ocean Commotion, an annual event meant to give students the chance to get up close and personal with coastal and sea life and the challenges facing those environments. This year 70 exhibitors taught students about topics as diverse as boating safety, mosquito control, and microplastics. CWPPRA outreach staff talked with students about the diversity of species found in Louisiana’s wetlands and the challenges of invasive species, giving students an opportunity to think about how different species impact ecosystems in different ways.

 

Oysters for Coastal Restoration

More than a seafood delicacy, oysters are an incredible natural resource. They are extremely helpful to our environment by filtering water, providing habitat, and controlling erosion. Adult oysters may filter up to two and a half gallons of water per hour, which in turn improves water quality. Oysters build reefs that provide habitat for fish, shrimp, crabs, and other aquatic animals. Oyster larvae need the hard, shell surface for settlement and growth. A special focus that has been put on oysters recently is their ability to control land erosion.

Oyster reefs have been constructed along eroding shorelines in an effort to lessen wave energy and ultimately reduce erosion. Seven of our nation’s fifteen largest shipping ports are located along the Gulf of Mexico. The wakes created by the cargo ships heighten erosion along an already disappearing coastline.

Globally, it is estimated that 85% of oyster reefs have been lost. Large-scale restoration projects can create man-made oyster reefs that duplicate many of the benefits of natural reefs. Oysters and the massive reefs provide a foundation for a healthy ecosystem. The Coalition to Restore Coastal Louisiana (CRCL) founded the Oyster Shell Recycling Program in 2014. This program collects shells from New Orleans area restaurants and utilizes the shells to restore fading oyster reefs that protect Louisiana’s coastline.  A majority of shell removed from the coast is not returned back to the waters. It is vital to Louisiana’s disappearing coastline that oyster shells are brought back to help as a line of defense for coastal restoration.