Lake Street Landing cofferdam to be tested, drained

A steel cofferdam installed to keep Lake Tashmoo at bay while the boat ramp is replaced at Lake Street Landing will be tested and drained this week. — Rich Saltzberg

A steel cofferdam installed to facilitate the Lake Street Landing project at Tashmoo Lake is scheduled to be tested and drained this week, according to contractor John Packer.

Cofferdams are designed to hold back water from work areas. At Lake Street Landing, the cofferdam hems in the old boat ramp. Once it is drained, a machine can tear up the old ramp and lay crushed stone as a base for the new ramp, Tisbury harbormaster John Crocker said. Then rebar and concrete work can commence, he said.

Packer said his crew took a breather last week after driving hard to complete all in-water work (piers, the dam, and bulkhead installation) by Jan. 15, after which winter flounder regulations prohibit marine construction. A modified permit from the Massachusetts Department of Environmental Protection and the U.S. Army Corps of Engineers allows work to continue inside the dam, Crocker said. The new ramp is modeled after the Lagoon Pond ramp, and will replace a crumbled one with a dangerous dropoff at its lower end, he said.