During its Annual Summit & Expo in Norfolk, Virginia, in June, the Western Dredging Association (WEDA) presented Environmental Excellence Awards, recognizing projects that demonstrate environmental excellence in each of three categories: Environmental Dredging, Navigation Dredging, and Mitigation and Adaptation to Climate Change.
The following prize winners exceeded the criteria of the WEDA Environmental Commission which are to “promote communication and understanding of environmental issues and stimulate new solutions associated with dredging and placement of dredged materials such that dredging projects, including navigation and environmental, are accomplished in an efficient manner while meeting environmental goals.”
The 2018 WEDA Environmental Excellence Award for Environmental Dredging was presented to the project team for Wagner Creek and Seybold Canal Restoration Project, Miami, Miami-Dade County, Florida. The project team members were the City of Miami, Sevenson Environmental Services, Inc., AECOM, and CH2M Hill Constructors, Inc.
Wagner Creek and Seybold Canal are designated by the State of Florida as Outstanding Florida Water and yet these waterways have suffered from contamination for many years. In fact, Wagner Creek was deemed Florida’s most polluted waterbody. These waters drain directly into to the Miami River, which discharges into the Biscayne Bay Aquatic Preserve and nearby Manatee Protection Zones. The protracted history of dioxin contamination in Wagner Creek, the sediment build-up in these waterways, and their location in one of Miami’s most populated urban areas created numerous logistical challenges, including rigorous permitting requirements for dredging contaminated sediments in a densely populated area that had prevented the removal of these sediments for decades. Dredging activities in manatee habitats required the utmost protection and preventive measures to avoid any injury or adverse impacts to these threatened marine species.
Sevenson working with AECOM (engineer/designer) and CH2M Hill Constructors provided a Design-Build service to the city of Miami to develop an effective dredge plan that allowed for these historic and vital waterways to finally be restored. A dredging solution was needed that could be permitted within 90 days from contract award. Hydraulic dredging was deemed too costly and non-permittable by Florida’s regulatory agencies and the U.S. Army Corps of Engineers (USACE). An innovative approach was found that allowed for a mechanical dredge solution, which complied with the strict environmental, logistical, and time-constraint requirements.
Most importantly, the environmental restoration of Wagner Creek and Seybold Canal stimulated new and innovative solutions for protecting marine, residential and industrial communities that can be utilized for future dredging work in other densely populated urban areas.
WEDA’s 2018 Environmental Excellence Award for Navigation Dredging was granted to the project team for the Florida Inland Navigation District Intracoastal Waterway Deepening in Fort Lauderdale, Broward County, Florida. The project team members were the Florida Inland Navigation District, Taylor Engineering, Inc., and Cashman Dredging and Marine Contracting Company, LLC.
Taylor Engineering designed and provided construction administration for a Florida Inland Navigation District (FIND) project to deepen the Intracoastal Waterway (ICWW) in Fort Lauderdale from -10 feet mean low water (MLW) to -17 feet MLW, plus 2 feet of allowable over-dredging, while avoiding environmental impacts and reducing long-term maintenance requirements.
The project site is part of a federally authorized 403-mile navigation channel along Florida’s east coast. In the 2.9-mile-long project area, the federally authorized project depth had become insufficient for safe navigation. However, it lies within a densely populated, highly urbanized area, where marine traffic ranges from small recreational vessels to commercial barges and super yachts. This creates a difficult work environment.
The project team remained conscious of all relevant environmental, technical, regulatory and social aspects that influenced the design, permitting and construction, including developing alternatives and evaluating benefits for long-term maintenance requirements, dredged material disposal, safe off-site material transport from the dredged material management area (DMMA) and direct and indirect impacts to seagrass and hard coral as well as to marine animals.
Other priorities were to cultivate effective working relationships with all stakeholders, and achieve design objectives by maximizing long-term channel design benefits, avoiding natural resource impacts, and minimizing impacts that were unavoidable. Noteworthy as well is that the project was constructed safely and efficiently, within budget and schedule. Ultimately, the project team rehabilitated the channel in such a way that it protected and preserved the ecosystem and simultaneously improved navigation safety.
WEDA’s 2018 Environmental Excellence Award for Mitigation and Adaptation to Climate Change was presented to the project team for Ninigret Marsh Restoration Project, Rhode Island. The project team members were J.F. Brennan Company, Inc., Rhode Island Coastal Resources Management Council, Save The Bay, Narragansett Bay, Town of Charlestown, Rhode Island, and Fuss & O’Neill, Inc.
Sea level in Rhode Island has been rising steadily and at an increasing rate. Observations by the Coastal Resources Management Council (CRMC) in many of Rhode Island’s salt marshes, including the marshes in Ninigret Pond, conﬁrm that salt marshes are beginning to drown in place. They are being converted to mud ﬂats or open water. The loss of these salt marshes translates into the loss of a natural buﬀer to storms and creates difficulties of coastal protection for communities along the shorelines. Salt marshes also filter nutrients that would otherwise pollute waterways, and they absorb carbon, which contributes to climate change.
CRMC and its partners designed a project that used sediment dredged from the breach-way channel to build up the elevation of the adjacent marsh. The project has preserved the functions of the existing salt marshes, making it more resilient to future sea level rise and storm events, it has slowed the entry of sediment into the pond, and has improved navigation by creating a deeper breach-way channel. Bird and fish habitats and ecosystem stability have also benefited.
J.F. Brennan brought a number of innovations to bear on the Ninigret project, including The RTK GPS used for dredge positioning and a state-of-art, high resolution single-beam bathymetric system (SBES). Marsh layout included the use of an RTK-GPS rover pole to conduct land surveys and drone technology to monitor the work and also provide some preliminary information prior to the final survey. A Marsh Excavator, which moved pipelines and assisted in the grading, allowed controlled discharge and increased production.