Corps of Engineers announces Miami Harbor project successes
Jacksonville, Fla. – The U.S Army Corps of Engineers announces the official construction completion on the Miami Harbor Deepening and Widening Project, the first major port deepening to a 50-feet depth in the southeastern United States. Along with deepening, which was finished in September, mitigation construction is also completed. Recent monitoring shows the mitigation features are functioning successfully.
“We are pleased at the success of the mitigation features,” said the Corps’ Jacksonville District Commander, Col. Jason A. Kirk. “The features include nearly 17 acres of seagrass and 12 acres of artificial reef.”
Recent surveys, conducted a year after construction of the 12-acre artificial reef, show an abundance of sea life and habitat colonization. Post-construction reports of the seagrass mitigation site show new seagrass recruitment growth and a 97% survival of planted plots.
Recent post-construction monitoring reports also provide a complete assessment and characterization of the sea floor communities during and after project work. The reports compare monitoring data to preconstruction surveys and information, and provide observations of project-related and natural sediment settling throughout construction. Scientists mapped the extent of project-related sediment during construction, which measures 252.4 acres across the hardbottom, middle and outer reef areas. Results show that sediment levels have either dissipated or are dissipating in most areas.
The greatest impacts associated with coral mortality over time appear related to a catastrophic, regional-scale coral bleaching/disease outbreak that continues to have a destructive effect on coral populations. White plague disease was widespread across all middle and outer reef compliance monitoring and control sites, and accounted for 85 percent of the total hard coral mortality at these sites. White plague disease is also directly responsible for 18.3 percent of total hard coral colony mortality of tagged colonies from near-shore sites.
Corals world-wide were stressed in 2014, which ranks as Earth’s warmest year since 1880, according to two separate analyses by National Aeronautics Space Administration and National Oceanic and Atmospheric Administration (NOAA) scientists. NOAA’s Coral Reef Watch expects the global-scale bleaching to last well into 2016. (See www.noaanews.noaa.gov/stories2015/100815-noaa-declares-third-ever-global-coral-bleaching-event.html).
High temperatures contributed to a significant region-wide bleaching event in August and September 2014, with another bleaching event in 2015. After the 2014 bleaching event, observers noted coral diseases spreading throughout the project area, starting at the southern control sites. Region-wide monitoring has now detected the disease as far north as Palm Beach County. Scientists report the white plague disease outbreak is still active throughout the region and coral mortality related to the disease is expected to increase across all sites in the future.
Upcoming monitoring efforts will focus on documenting recovery of areas previously monitored, as well as observing and determining the distribution of any permanent effects across and along the reef system near the channel.
For more information and copies of the Miami Harbor post-construction monitoring reports, go to www.saj.usace.army.mil, click on ports in the right column, and then Miami Harbor in the right column.
Release no. 15-099