Bio-Engineered Oyster Reef Demonstration (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.

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

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.

• Federal Sponsor: National Marine Fisheries Service
• Local Sponsor: Coastal Protection and Restoration Authority

More Information on this Project:

•  Further Reports
•  Results and Discussion (page 56-68) LA-08 2014 Operations, Maintenance, and Monitoring Report

Further Websites Regarding Oyster Reef Restoration:

• Tetra Tech
• Oyster Restoration Workgroup
• Coast and Harbor Engineering

 

 

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)

 

 

The Future of Urban Deltas

An urban delta may be defined as a city home to as many as half a billion people living and working in a deltaic zone where rivers meet the ocean. These communities are coastal, riparian, & urban which are threatened by increasingly strong typhoons, hurricanes, uneven rainfall patterns with droughts [6].

According to New America, the 3 major global trends are climate change, rural to urban migration, and urban economic concentration. The Delta Coalition is the world’s first international coalition of governments joining forces to share knowledge, innovation and sustainability practices to create more resilient urban deltas [1].

Policy makers, politicians, NGOs, academics, engineers, designers and consultants worked and talked together about the challenges and opportunities of the world’s urban deltas at a Sustainable Urban Deltas conference in 2016 [4].

Deltaic countries who have joined The Delta Coalition  include: Bangladesh, Colombia, Egypt, France, Indonesia, Japan, Korea, Mozambique, Myanmar, the Netherlands, the Philippines, and Vietnam [6]. Other organizations moving forward toward sustainable urban deltas are PRIVA, and Sustainable Urban Delta where waste water recycling, or creating bio-fuel from food waste are examples of sustainable innovations for urban deltas [5].

World City Populations 1950-2030

By one count, over 1/4 of the world’s 136 largest port cities occupy deltaic formations [2] and the percentage of people living in urban areas “has grown from 34% in 1960 to a projected 66% in 2050” [6].

Urbanization is directly related to economic growth, creating more jobs, and increasing population; though this steadfast increase is positive in some ways, it also increases the chance of poor governmental preparedness resulting in poor living conditions, quality of life, and slums [6].

“It is clear we can only solve the world’s environmental problems if we solve the problems of our cities first” [1]. — According to Chief Curator of IABR ( International Architecture Biennale Rotterdam), world leaders must  invest in learning the capacity of cities, experiment, and join networks while creating new and positive urban visualizations towards a productive, clean and socially inclusive city [3].

In regards to Louisiana’s urban delta, CPRA developed Louisiana’s Comprehensive Master Plan for a Sustainable Coast to incorporate coastal wetland protection and restoration for coastal and deltaic communities, and CWPPRA projects are consistent with the Master Plan.