GZA was retained by the Town of Fairfield to evaluate the feasibility of dredging the channel within Pine Creek, a tidal river along the north shore of Long Island Sound. The channel was last dredged in 1968 and has shoaled to the point where recreational boating has been severely impaired.
GZA conducted a hydrographic survey along a 1± mile reach of the river. Using aerial photography and the original design drawings, GZA overlaid the previously permitted channel geometry onto the new hydrographic survey, developed cross sections and calculated a maintenance dredge volume of 32,000 cubic yards. Minor deviations in the channel alignment were made to avoid undermining bulkheads that were recently installed along the southern edge of the channel.
Sediment samples were obtained using gravity coring equipment at three (3) locations in the project area. Samples were analyzed for grain size, metals, polyaromatic hydrocarbons, polychlorinated biphenyl and pesticides.
The results of the testing were evaluated with respect to potential upland and open water disposal options. For upland disposal, results were compared to Direct Exposure Criteria (DEC) established by the Connecticut Department of Energy and Environmental Protection (DEEP). Data was also compared to reference data from the designated open water disposal sites: Western Long Island Sound Disposal Site and Central Long Island Sound Disposal Site. Based on the data collected, GZA provided its opinion of the deposition of the dredged material.
GZA identified and summarized the environmental permits that were required to implement the project and developed a schedule for preparing the applications and the expected review time by the agencies that included: DEEP Office of Long Island Sound Programs and the U.S. Army Corps of Engineers. Using historic aerial photography, GZA recommended the Town consider dredging an alternate channel at the mouth of Long Island Sound by evaluating accretion and storm damage tendencies and potential. GZA also assisted the Town by providing guidance on dredging and disposal techniques and permitting issues due to Superstorm Sandy which transported over 5,000 cubic yards of sand into the channel from Fairfield Beach.