• WPA, Chapter 91, 401, 404 Permitting,
• Sediment sampling and testing
• Eelgrass survey
• Extensive disposal alternatives analysis
• Agency coordination
The Woods Hole, Martha’s Vineyard and Nantucket Steamship Authority (SSA) provides ferry services from Cape Cod to the is-lands of Martha’s Vineyard (via Woods Hole) and Nantucket (via Hyannis).
Challenge
The Nantucket Ferry Terminal has two functional slips and a wharf that service passengers and freight to/from the island. The wharf is the primary location where cargo is delivered to/from the island and with significant accumulation of sediment alongside the berths, freight vessels need to time their arrivals/departures with the tide. Some areas have shoaled to -9 MLLW which is 5 feet shallower than the currently authorized depth of -14 MLLW. Furthermore, some portions of the dredge area are within and adjacent to eelgrass beds on the south side which complicated and potentially lengthened the permitting process. Time-of-year (TOY) restrictions imposed by the Massachusetts Division of Marine Fisheries (DMF) limit dredging to a narrow winter 2022/2023 window so permits needed to be obtained by December 2022 in order to complete the dredging before the TOY restriction. Permit agencies required identification of interim and final disposal locations so GZA was tasked with identifying candidate disposal sites.
Solution
GZA managed a robust sediment sampling and testing plan that accounted for all potential disposal options available from open water disposal at Cape Cod Bay Disposal Site to upland disposal/reuse on the island. GZA coordinated closely with MA DEP Solid Waste and 401 Divisions, local contractors, local engineering firms, various Town departments and the landfill and its consultants to find a suitable location for 1,800 cubic yards of primarily sandy sediment. GZA was able to arrange for interim stockpiling at a local construction yard at a significantly reduced cost with ultimate disposal at several locations on the island. GZA expedited the permit through several on-line coordinated meetings with MA DEP and the U.S. Army Corps of Engineers. The dredge foot-print was modified to avoid impacts to eelgrass in the southern slip which also expedited the permitting.
Benefit
When completed, the freight vessels will be able to navigate to and from the island unencumbered by tide cycles.