Maintenance dredging of the Federal navigation channel near the Chelsea Street Bridge in Chelsea and East Boston is being proposed by the U.S. Army Corps of Engineers, New England District, with work anticipated by 2012. Once the existing Chelsea Street Bridge is replaced with a new vertical lift bridge by others, the Corps will be able to modify the Federal navigation channel in that area. Although the Chelsea Creek navigation channel was authorized to a width of 225 feet under the River and Harbor Act of 1962, the existing Chelsea Street Bridge prevented the channel from ever reaching its authorized width. “The project area is located approximately 125 feet downstream of the bridge to approximately 350 feet upstream of the bridge,” stated Mike Keegan, Project Manager with the Corps’ New England District, Programs/Project Management Division. “There are two alternatives currently under consideration to widen the channel. Both alternatives are located in disturbed areas where previous vehicular or railroad bridges, and utilities were constructed.” Under the first alternative, a minimum 140-foot-wide channel would be created in the vicinity of the new Chelsea Street Bridge. A minimum 175-foot-wide channel represents the second alternative. The 175-foot-wide channel alignment depends on bulkhead modifications that non-Federal interests must design and complete. These modifications are required before the navigation channel can be widened to 175 feet. To the channel depth of -38 feet Mean Lower Low Water (MLLW), as authorized in the Water Resources Development Act of 1990, both alternatives would widen the channel. Fuel tankers using the existing Chelsea Creek currently have less than six feet of clearance between the existing Chelsea Street fenders. Any constriction of the navigation channel will be eliminated by the new vertical lift bridge now under construction. The Federal navigation project aims to widen the navigation channel in the Chelsea Street Bridge area promptly following completion of the new bridge. Larger vessels could potentially access the oil terminals upstream of the bridge if the channel is widened, which may increase the volume of home heating oil and other Massachusetts commodities while reducing transportation costs. Additionally, the project addresses potentially hazardous navigation conditions. Following completion of the new bridge, dredging is expected to commence early in 2012. Approximately 34,700 cubic yards of material, including two feet of over depth dredging, would be removed mechanically to widen the channel to 140 feet. Of this total, roughly 5,100 cubic yards of surface material is unsuitable for ocean placement and will be deposited in the existing Confined Aquatic Disposal (CAD) container built during the Boston Harbor Navigation Improvement Project deepening. This container sits at the upper end of the Chelsea Creek navigation channel. The remaining 29,600 cubic yards will be placed at the U.S. Environmental Protection Agency-designated Massachusetts Bay Disposal Site (MBDS), located 20 miles offshore. This active disposal site has been used for dredged material that has undergone chemical and biological testing. Currently under preparation is an Environmental Assessment for this project. Whale observers will be stationed on scows traveling to the MBDS from Feb. 1 to May 31 to protect endangered right whales and prevent potential ship strikes. The Corps is evaluating the project’s potential effects on Essential Fish Habitat and has preliminarily determined that designated fisheries resources will not be significantly impacted.
Navigation Channel Under Chelsea Bridge Under Consideration for Dredging in 2012
