Large-scale coastal dredging projects have the potential to add significant stress to coral reef, communities in surrounding areas, especially if impacts are undetected or fail to be detected in time.
Therefore, extensive monitoring is needed at a timely scale, relevant to allow adaptive management of projects during dredging.
How do scientists get to the bottom of it?
The U.S. Army Corps of Engineers (USACE), Jacksonville District, in partnership with the National Oceanic Atmospheric Administration (NOAA) and the U.S. Army’s Engineer Research and Development Center (ERDC) are working to monitor the water quality and oceanographic conditions of the ocean.
NOAA’s ecological forecasting tool known as ‘Environmental Information Synthesizer for Expert Systems’ (EISES) is being tested for the first time in a maintenance dredging project in Port Everglades, Fort Lauderdale, Florida, in a multi-agency collaborative effort to help forecast water quality impacts which may be associated with dredging operations.
According to Dr. Xaymara Serrano, coral biologist at USACE, “The ultimate goal is to be able to use this tool at Port Everglades for the deepening project to assist with adaptive management of the project during construction”.
This tool was originally developed by NOAA’s Atlantic Oceanographic and Meteorological Laboratory (AOML) for forecasting coral bleaching in 1998.
EISES uses artificial intelligence to expedite and automate analysis of environmental data from satellite images, in-situ instruments, and/or in-situ observations to help inform responses to ecological events. In this collaboration, EISES will use data from sensors mounted to the seafloor which currently measure turbidity, total suspended solids (TSS), sediment deposition, seabed light (PAR), waves, currents, temperature and salinity.
Scientists also developed a diver-based monitoring protocol that can assess indicators of sediment stress levels and sediment depth measurements in a three-tiered approach.
Furthermore, the diver-based survey data can also be integrated with EISES after field surveys are completed.
The data collected can then be disseminated to various stakeholders through automated reporting.
Reporting can be transmitted daily, weekly or monthly in near real-time.
Next, EISES can generate alerts that help determine if/when dredging corrective actions are needed, using a color-coded system, sort of like a stoplight indicator (green, yellow, red).
“Lessons learned from the recent Miami deepening project highlighted the need for the Corps to have a higher level of oversight over dredging operations,” Serrano said.
The Corps developed a framework to assist with the decision-making process during dredging operations for the deepening project, the Adaptive Management Plan (AMP).
Serrano admits, “The goal of the Adaptive Management Plan is to help identify and/or minimize permanent project-related impacts to nearby sensitive marine resources, including corals, before it is too late”.
“I contacted the team at ERDC so that they could assist with developing the deployment plan for the bottom-mounted sensors and field operations, said Serrano.
[Also,] I contacted the NOAA/AOML team to assist with linking the bottom-mounted sensors to a buoy for near real-time data transmission.”
The Corps’ goal is to deploy instruments in the water for approximately one year before the deepening project begins.
“We are currently at the testing stage of this work,” said Serrano.
The habitat of the ocean floor is ever-changing.
Researchers expect to minimize potential impacts of key stressors typically associated with dredging (e.g. turbidity, sedimentation, light) by monitoring water quality in near real-time, and automating the process of reporting and generating alerts. EISES alleviates the need for relying solely on divers to do all the environmental monitoring.
Long gone are the days where divers needed to do all the work.
“That’s the beauty of this ecological forecasting tool. The bottom-mounted sensors can automatically feed the data to EISES because the buoy is transmitting the data near real-time”, said Serrano.
“The only data that will be obtained by divers is the biological data (e.g. organismal condition and sediment depths), which will be collected bi-monthly during dredging operations at a specified array of stations north and south of the Port Everglades channel.”
By Maya Jordan, USACE