Mystic River Maintenance Dredging

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DETAILS

Client: USACE New England District
Value: $8,200,000
Project Date: December, 2014 - March, 2015
Project Cut-sheet: Download

SUMMARY

Cashman conducted maintenance dredging in several areas of the Mystic River in Connecticut: the 12- and 15-foot Federal Channels, the 9-foot Federal Anchorage and Turning Basin, and the 5-foot State Channels. The project required the removal of ~203,000 cubic yards of material by mechanical dredge from the Federal Channel with the removed material transported by scow and disposed at the New London Disposal Site (located ~five miles from the mouth of the Mystic River). Cashman also was responsible for the removal of ~26,000 cubic yards of material by mechanical dredge from the State Channels with disposal at the Central Long Island Sound Disposal Site (located ~35 miles from the mouth of the Mystic River).

PROJECT HIGHLIGHTS

  • Dredging work was sequenced so that all dredging of the channel above the highway bridge to the upper wharves at the Mystic Seaport Museum was completed prior to dredging in all other areas.
  • Cashman Dredging's use of a multibeam type surveying method for daily quality control surveying was a key factor in completing the dredging by limiting shoals from forming in the soft sediments in the Federal and State Channels and Federal anchorage area.
  • Cashman's Dredge Quality Management electronic tracking system for the scows operated consistently over the 115 scow disposal events for the dredging of the Federal Channel and 17 scow disposal events from the State Channels.
  • In spite of extreme winter weather where the area experienced severe cold and two blizzards during the month of January 2015, Cashman was able to complete the project on time.
  • According to the client's Lead Project Engineer's contractor assessment, "Their [Cashman's] good housekeeping on their dredges and methodical work practices were evidence of the safety culture that is ingrained in their Corporation. There were ~33,000 safety exposure hours with no recordable or reportable lost time accidents encountered on the project despite winter weather conditions and working in Mystic Harbor, which is heavily congested with private docks and marinas alongside the Federal Channel."
  • The federal client was also pleased that Cashman's "exceptional" on-site supervision and control of subcontractors resulted in a very successful project that required limited on-site Government Quality Assurance oversight during the two phases of the dredging project.
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