Cove River tidal marsh restoration, pedestrian bridge and Sea Bluff Beach Park improvements
Location
West Haven, CT
This project received ASCE/CSCE's Achievement in Civil Engineering Award in Coastal Resiliency
The Cove River tidal estuary has a long history of active manipulation through the historic use of tide-gates to limit or control the tidal waters of Long Island Sound into the formerly thriving estuary located upstream. Salt hay cultivation and upstream flood management goals led to the marsh to be cut off from its saltwater inflows, causing decades' worth of ecological harm to the marsh. The native vegetation in the marsh has been outcompeted with invasive species such as phragmites, and the marsh platform has shown signs of subsidence due to the lack of tidal sediment accretion and the decomposition of organic matter on the tidal platform.
The SLR Water Resource Engineering team was approached by the City of West Haven in 2019 to design (and in 2021 to construct) a series of Self-Regulating Tidegates (SRTs) to allow saltwater back to the marsh for the first time in decades while simultaneously providing flood protection for the elementary school and hundreds of flood prone residents situated on the fringes of the marsh. The design accomplishes these goals while being flexible enough to continue operating successfully decades into the future in the face of climate change and sea level rise.
The project also involved the removal of two sets of old tide gates, one located on the Captain Thomas Boulevard bridge and one located downstream near Sea Bluff Beach. In place of the downstream structure, which was historically used as a pedestrian crossing across Cove River, a prefabricated aluminum truss bridge was designed to restore pedestrian connectivity between the two parks. The bridge was retrofitted with decorative, customizable LED lighting, which is controllable by the City via an internet interface.
In conjunction with the pedestrian access bridge, numerous connected pedestrian walkways, benches, lighting improvements, Americans with Disabilities Act (ADA)-accessible compliant parking and beach access pathways, and a permeable paver parking area were designed by SLR and implemented into the site restoration plan.
The SRTs have been in place and functioning since October 2021, and already after one growing season there have been anecdotal reports of increased native vegetation species, such as Spartina alterniflora and glasswort, and reductions in the extents of phragmites.
The project was very well received by residents and the public, and while several minor punch list items remain to be completed, the project was substantially completed in December 2022 and had a soft opening to the public in July 2022 after a “Bridge Lighting Ceremony” on July 19. In attendance at the ceremony were representatives from various City departments and the State of Connecticut, including Mayor Nancy Rossi as well as several state senate representatives.
