One problematic event in the timeline of the PCB debacle on the Hudson, discussed yesterday here, was the removal in 1973 of the Fort Edward Dam, a hydroelectric dam about 50 miles north of Albany.

This dam was downstream from much of General Electric’s PCB discharges at Fort Edward and Hudson Falls, NY, and a tremendous quantity of sediment laden with PCBs was trapped behind it.  Taking out the dam led to these PCBs flowing further down the river, stirred up and transported downstream further by subsequent flood conditions and high river flows.  Removing the sediments properly at the time would have helped avoid a world of problems.

The book, Guidelines for retirement of dams and hydroelectric facilities, published by the American Society of Civil Engineers in June 1997 (googlebooks here), goes into some of the sad history of this event, which included a lot of litigation. notes the work, River Restoration and Dam Removal in the American West: A Comparison of Policy Change Across Political Jurisdictions, quoting

The FPC (Federal Power Commission) conducted one of its first EISs (Environmental Impact Statements) on the proposed removal of Fort Edward Dam and pursuant to this review; it approved the removal in 1973. This early case of dam removal is significant for a number of reasons. Most significantly, pursuant to hearings conducted by the FPC, the dam owner, the Commission, and state and local officials were found not to have exercised due diligence in planning for and completing the dam removal. Significant water quality problems were also created by PCB-contaminated sediments released from behind the dam. In 1976, New York State closed the Hudson River for fishing, decimating a $40 million striped bass fishery.

Ultimately, the FPC ruled that penalties were not warranted, and pretty much gave those involved a pass.

Presumably, such EISs are done better nowadays, given the the FPC statement in 1978 that

Any license for dam removal in the future will be drafted differently, with the lessons of Fort Edward in mind.

Any river engineering work must involve in the planning process a careful analysis of sediments, their chemical composition, and how to manage them.