Conowingo Dredging

[Steve6902]

On the one hunting site that I'm on they are talking about this. Seems that it may cause some harm to the fishing on the flats?? Just want to get people's opinions. Seems like a good idea, BUT what to do with the dredge material.

http://www.baltimoresun.com/news/mar...229-story.html

[Mark]

The Baltimore Sun article is a good summation of a very complex problem that has been under study for years. For those interested, there is much information available on-line about the scope of the problem with numbers that are mind-staggering in terms of cost and the amount of sediment that must be removed.

However, a key discovery in studies by both the Army Corps of Engineers and the University of Maryland is that the Susquehanna is not the primary source of Bay pollutants. The rest of the Bay’s watershed accounts for 80 to 90 percent of sediment runoff – and that was the case even during the infamous Hurricane Agnes in the 1970s.

The problem now is that after nearly 90 years of operation the dam is reaching its capacity to hold back sediment. So, those percentages above could change in the future unless portions of sediment behind the dam are removed periodically, and/or efforts to control runoff upstream are strengthened.

Like most issues in life, this analysis becomes a huge cost/benefit drill. And then the big question is who pays for the long-term solution – Maryland, New York, Pennsylvania (the source of most of the Susquehanna’s sediment), the federal taxpayers or Exelon Power, the owners of the dam. Most likely each will share a piece of the cost. That is the financial and political minefield at play here in addition to what to do with the sediment that is dredged.

Let’s hope for the Bay’s future that this test dredging operation is successful in finding answers and disrupts fishing on the Flats as little as possible.

[kevinfry]

since the sediment is mostly topsoil, i cant believe there would be no market for the material. Of course, that would not pay for removal, but would be an offset.

[Steve6902]

It is my understanding that the sediment is contaminated with heavy metals, PCBs, and other pollutants. So people are concerned about where they will deposit the dredged material. I know that, I would not want that stuff in my backyard, polluting my well water or worse.

[kevinfry]

i'd like to see that lab work.....

[yakscientist]

It is my understanding that the sediment is contaminated with heavy metals, PCBs, and other pollutants. So people are concerned about where they will deposit the dredged material. I know that, I would not want that stuff in my backyard, polluting my well water or worse.

We are currently working on a few projects with similar contaminated sediments, and I feel the same way. We have had sediment cores come out of the ground with oil seeping out, or bright green hazardous waste peppered throughout. It's nasty stuff, and typically the protocol is to dredge it and then truck it up to a remediation site where they either store it in huge tankers, or somehow clean it. It's very expensive, and I am in complete agreement with getting all 6 states of the Ches. Bay watershed to split the bill. How we would go about convincing them to do so, I have no idea.

[silasvirus82]

Coming from a civil construction background, I can confirm how difficult it is to get dispose of unwanted material. I have worked on projects with dry clean topsoil that we can't give away, and often end up paying a landfill to take it after hauling it to them. If the material is contaminated in any way, forget about it, and nobody will accept it without lab tests. Dredging material is about as bad as it gets. Not only is it usually contaminated, it takes years to dry out, or hundreds of thousands of dollars to expedite the process by turning over the material with heavy equipment. The last project I did at Quantico like this, we only dredged about 10,000 CY from a small reservoir on Chopawamsic Creek and spread out over a field for temporary stockpile. After two years, we were delayed for many reasons, we started excavating the stockpile and it was still saturated only 1' down. We were expecting this, but it's still amazing how long that soil can hold water. 31M CY of contaminated dredging material, that's an entirely different ball game and will likely result in the construction of a special landfill built just for this material. If they are smart, they will build the holding cell oversize to accept future dredging material, and not let it get this backed up in the first place.