Anacostia River
Cottrell Contracting Corporation has been a industry leader for dredging services for over 80 years in February 2003, the Baltimore District Army Corps of Engineers awarded to Cottrell Contracting Corporation a $1.9 million contract for the dredging of the Anacostia River.
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The Anacostia River project is an excellent example of a successful environmental project. The Anacostia River is a tributary of the Potomac River that runs through our nation's capitol. From the river, you can see such sites as the national Arboretum, as well as the old RFK stadium where the Washington Redskins football team played not too long ago. The Anacostia had not been dredged in over 30 years and was dying due to lack of oxygen from the shoaling that had taken place. It was obvious that the river needed dredging; however, there was no land available to build a dredge material containment site. The answer? Dredge the channel to restore depth and health to the river and use the dredge material beneficially to create inter-tidal wetlands adjacent to the river.
Due to the fact that the portion of the river to be dredged was only accessible by small dredging equipment, Cottrell Contracting chose to utilize its 12" Dredge Blue Ridge for the project. Prior to the dredge's arrival, over 5,000 linear feet of sheet pile was driven to establish two "cells" that would later become wetlands after being filled with dredge material. The average water depth in the cells before dredging began was approximately -3.5 mean low water (MLW). The project called for dredge material to be pumped to an elevation of +1 1/2 MLW to fill the cells. The allowable tolerance was plus or minus 6". To ensure that the final grade was achieved, Cottrell used an amphibious excavator to grade the pumped material to its final elevation. Cottrell Crew, experienced from many prior environmental projects, pumped over 200,000 cubic yards into the wetland cells. All material was checked for final grade by the Army Corps of Engineers and found to be within tolerance. The two cells were given time to consolidate and planted with native plant species. The result was a tremendous success.
Lockwoods Folley
In 2015, Cottrell Contracting was the only bidder for a Habitat Restoration Project to dredge the Eastern Channel of Lockwoods Folley in the southern shores of North Carolina. The project was a private one, contracted out by Moffatt & Nichol, a private firm of Oak Island, N.C..
The primary purpose of the dredging project was to clear a closed inlet connection in order to restore a safe navigable channel for commercial and recreational fisherman, as well as to provide sand for the purpose of beach nourishment. The direct result of this dredging within the inlet would improve shellfish habitats and other marine life.
By reopening the channel leading to Atlantic Ocean, flow to estuaries would increase, thus improving water quality in those waters known to be at one time a densely populated fish nursery and a location for shellfish to thrive.
In addition to the fishery improvements, approximately one and a quarter mile of beach was to be shaped and extended out seaward. This type of beach nourishment has proven to be beneficial to the sea turtle spawn, including mainly Loggerheads, as well as the Green Turtle and Kemp’s Ridley turtle.
Not only would sea life benefit from the completion of this contract, a number of people’s homes along the shoreline who’s structural integrity was hanging in the balance of a decimated foundation. Adding stand in front of these homes would surely extend the lifespan of these homes and protect the people living in them.
In just over two months’ time, the Dredge Marion, a sixteen inch Cutter Suction Dredge, was able to complete the dredging contract. Removing just under 225,000 Cubic Yards from the inlet channel, Cottrell Contracting successfully fulfilled the terms of the contract.
