Thursday, November 5, 2015

The Murky Waters of USACE Dredging

USACE photo - Mouth of the Clinton River on Lake St. Clair

  -- the first in a series --

Every few years, the U.S. Army Corps of Engineers (USACE or the Corps) arranges to dredge channels in the mouths of rivers entering international waters in southeast Michigan to remove accumulated sediments that interfere with navigation.

Two examples are the Clinton River and the River Rouge.

Over several months in 2009-2010, a Corps contractor removed 17,454 cubic yards of sediment from the mouth of the Clinton River, generally to a depth of eight feet, at a cost of $338,413.

In August 2012, the River Rouge navigation channel was dredged to a depth of 21 feet.  It cost $363,886 to remove 39,951 cubic yards.  

In both instances, the dredgings were deposited in confined (land-based) disposal facilities.

The Clinton and Rouge dredging projects are dwarfed by those in Cleveland and Toledo, but all are subject to similar conflicts between commercial, public health and environmental interests.  

Many such projects are affected by Corps machinations to utilize open-water (lake) dumping of dredged sediments, instead of confined or land-based disposal.  Open-water disposal is simpler, faster and cheaper (cheaper if you disregard the environmental consequences and risks to public health).


When sediment contains toxins and other pollutants, the question of how best to dispose of the contaminated dredgings arises.

Public concerns have re-emerged this past year in Cleveland and Toledo about dumping contaminated sediments from river channels into Lake Erie.

In Cleveland, the Corps proposed to dredge the six-mile Cuyahoga River navigation channel and dump the dredged sediments in the lake.

The State of Ohio objected to open-lake disposal because the sediments, especially in the last mile upstream, were heavily contaminated with toxins, including polychlorinated biphenyl (PCB), from steel production years before.  The state maintained that open-lake dumping would create a public health hazard.

Although Congress had authorized enough money for confined (on-land) disposal, USACE insisted that some other party, apparently meaning the State of Ohio, pay for the more expensive confined disposal of sediments dredged from the sixth mile upstream.  

Ohio refused and sought relief in federal court.  This past May, the judge agreed with the state, ordering the Corps to dredge the six-mile channel, place all of the sediment in a confined disposal site and absorb the cost.

USACE may be down but it’s not out.  It has at least one more trick up its sleeve to re-establish open-water dumping, if not off Cleveland, then perhaps everywhere else.


Next in this series, we’ll look at Toledo, the 900 pound gorilla in the zoo of Great Lakes dredging.

The series will conclude with an analysis of a Corps “experiment,” the underwater equivalent of a Rube Goldberg contraption.  Junk science at its best!

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