Cove River tidal marsh restoration, pedestrian bridge and Sea Bluff Beach park improvements

City of West Haven, CT
West Haven, Connecticut, USA
  • Water resources engineering

This project received a 2023 Achievement in Civil Engineering (ACE) Award in Coastal Resiliency and a 2024 Merit Award from ACEC-CT

Challenge

The Cove River tidal estuary upstream of Captain Thomas Boulevard in West Haven, Connecticut, has a long history of active manipulation. Salt hay cultivation and upstream flood management goals have 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 had been outcompeted with invasive species such as phragmites, and the marsh platform had shown signs of subsidence due to the lack of tidal sediment accretion and the decomposition of organic matter on the tidal platform. SLR was contracted by the City of West Haven to address the environmental degradation in the area, and incorporate a number of related community benefits, including pedestrian access, parking, and park improvements.

Solution

The complex aspect of the project included the detailed assessment of environmental degradation in the area, and the development of an approach to a self-regulating system to mitigate flooding hazards, and restore tidal flows. The project therefore required two divergent management goals to be met:

  1. Maximize tidal saltwater flushing to promote marsh restoration through the reintroduction of saltwater, increase salinity to kill invasive plant species, reduce oxygenation and decomposition, and introduce tidal sediment accretion to increase the tidal marsh’s resilience to sea level rise.
  2. Limit tidal flushing to a predefined elevation to protect upstream properties from flooding, which includes residential homes and an elementary school.
  • A view from Captain Thomas Boulevard of the Cove River Tidal marsh in 2023, one year after the installation of the tide gates.
  • Closer view of the two 6-ft diameter Self-Regulating Tidegates (SRTS) as well as two 6ft by 8.6ft stainless steel flapgates were installed beneath the Captain Thomas Boulevard bridge to regulate flow in the Cove River tidal marsh
  • An aerial view of the two 6-ft diameter Self-Regulating Tidegates (SRTS) as well as two 6ft by 8.6ft stainless steel flapgates were installed beneath the Captain Thomas Boulevard bridge to regulate flow in the Cove River tidal marsh
  • An evening view of the pedestrian bridge showing the safety fencing, bollards, and recessed lighting on the bridge.

Impact

The project was completed within the project budget, and on-schedule, and was very well received by residents and the public.Corrected tidal flow is allowing the marsh to self-heal. Access and recreational opportunities have been made safe and enhanced.

The marsh now has two new osprey pair for a total of four, wading birds all summer and waterfowl all winter, and the reconnected pedestrian access in the park has seen a huge increase in usage and enthusiasm.

“I’m proud to both showcase the work done and explain the many benefits of the component parts to our public.”

Mark E. Paine, Jr,. Director of Parks and Recreation, West Haven, CT