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What does "the Conowingo Dam's capacity to trap sediment" refer to?
Over the past 80 years or so, the dam has trapped, on average, somewhere around 2 to 3 million tons of sediment each year and has held it in more or less permanent storage. As the dam has filled with sediment, its trap efficiency has decreased to zero, and most of the future sediment delivered to the dam from upstream will be released to the bay. The Conowingo Dam has been doing a great favor to water quality in the Chesapeake Bay for decades, but due to the physics of the system, it no longer will be able to continue to protect the Bay. In my professional opinion as a hydrologist, the dam has been a hero, and not a villain in the water quality story in the Bay.
 

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Discussion Starter · #5 ·
Over the past 80 years or so, the dam has trapped, on average, somewhere around 2 to 3 million tons of sediment each year and has held it in more or less permanent storage. As the dam has filled with sediment, its trap efficiency has decreased to zero, and most of the future sediment delivered to the dam from upstream will be released to the bay. The Conowingo Dam has been doing a great favor to water quality in the Chesapeake Bay for decades, but due to the physics of the system, it no longer will be able to continue to protect the Bay. In my professional opinion as a hydrologist, the dam has been a hero, and not a villain in the water quality story in the Bay.
You are 100% correct. If it were not for Conowingo and the other up steam dams, the mouth of the Susquehanna would now be somewhere near the upper end of Spesutie Island or Turkey Point and the flats would be a tidal marsh just like the upper Gunpowder.
 

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So how do they fix the issue? not playing devils advocate but what are some good solution ideas?
 

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Just as the channels were cleared with the dredging and battery island expanded with the material from the operation. The same type dredge could be used to fill rail cars next to the river and shipped over to the nearby quarries that could be lined to keep the hazardous nuclear mud from entering the ground water. The Stewart family could make billions more from the stripped land and the bay could be saved!!! Until then Exelon will keep scouring the silt off down into your bay.
 

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Over the past 80 years or so, the dam has trapped, on average, somewhere around 2 to 3 million tons of sediment each year and has held it in more or less permanent storage. As the dam has filled with sediment, its trap efficiency has decreased to zero, and most of the future sediment delivered to the dam from upstream will be released to the bay. The Conowingo Dam has been doing a great favor to water quality in the Chesapeake Bay for decades, but due to the physics of the system, it no longer will be able to continue to protect the Bay. In my professional opinion as a hydrologist, the dam has been a hero, and not a villain in the water quality story in the Bay.
Thanks Bill H, and Jerry I didn't know that about the dam.
 

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Bill H,

Thank you for providing your informed perspective on this topic!

There are many talented and knowledgeable posters like you that provide a wealth of information on this website that help people with non-technical backgrounds understand important issues.

Of course the ongoing challenge is sorting through the noise so we can hear and pay attention to the signals....and keeping the good people posting when trolls and others challenge them.
 

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Just as the channels were cleared with the dredging and battery island expanded with the material from the operation. The same type dredge could be used to fill rail cars next to the river and shipped over to the nearby quarries that could be lined to keep the hazardous nuclear mud from entering the ground water.
Sounds reasonable. Has anyone ever actually proposed this?
 

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Just as the channels were cleared with the dredging and battery island expanded with the material from the operation. The same type dredge could be used to fill rail cars next to the river and shipped over to the nearby quarries that could be lined to keep the hazardous nuclear mud from entering the ground water. The Stewart family could make billions more from the stripped land and the bay could be saved!!! Until then Exelon will keep scouring the silt off down into your bay.
Please underst5and that Exelon does not create the sediment. Thank the upstream land users for that. Also remember that if the dam was not there, that sediment would end up in the Bay anyway. Not one ounce of the sediment and associated nutrients that get to the Bay is the fault of the dam and reservoir. As a matter of fact, as I noted earlier, that system has protected the Bay for 80 years simply as a by-product of its power production role.
 

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Sounds reasonable. Has anyone ever actually proposed this?
Many thoughts have gone in to this or similar proposals. The issue is the cost/benefit ratio, and who just is going to pay to remove this potentially hazardous material and dispose of it. The responsible parties are the upstream land users in Pennsylvania and New York. They have little interest in cleaning up the Bay, and even less interest in paying for it. Exelon is not to blame for the sediment, so they probably should not be a responsible party (deep pockets does not imply culpability). Taxpayers from Maryland could pay for it. Or should it be the responsibility of all U.S. Taxpayers? These are the devils in the details.
 

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Eggs, wine, coffee, chocolate, and now dams are good?.. Can we add Cuban cigars and hookers to the list please...
Sure Lou those would have my vote as long as they pay taxes like other businesses--and while we are at it lets also add the federal government and EPA as the only ones with any authority to force the States to address the upstream sediment and nutrient pollution issues.
 

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Eggs, wine, coffee, chocolate, and now dams are good?.. Can we add Cuban cigars and hookers to the list please...
I never said that dams are good. I only said that in regard to pollution (sediment and phosphorus, specifically), this particular dam has had a beneficial effect on the Bay. I also understand that now that the trap efficiency has decreased, the delivery rates of these specific pollutants will be be more variable than if no dam were in place (scour during very high flow events, storage during lower flow events), but "on the average" delivery will be the same. Additionally there are other potential negative consequences of dams such as effects on anadromous fish, etc. As far as the ladies of the night and embargoed cigars go, I just assume that they were never really off some people's list of beneficial things.:))
 

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no one knows how the sediment would effect the bay if the dam were not there. Personally, I feel the bay could handle it if the dam were not there. It would come down during every storm and be spread out evenly like nature intended it to do....until someone slapped a huge concrete road block in front of it. Now someone, whoever owns it, is making a hell of a lot of money of something that's free, and if they want to keep making a hell of a lot of money off of it, it should be their problem to correct the issues the dam causes or remove it all together. Sediment ran down stream a hell of a long time before the dam was built and the bay was fine, so to say it saved the bay is premature and inaccurate.......because we all know, it spills a hell of a mess after major rains as seen on sat imagery posted more than once on here. I say the dam is excelons problem, they should be liable for it.
 

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....but, don't worry about it....even if they're found liable and have to correct it...they'll just pass the bill on down to their customers and hit us with a "delivery charge" for the water running freely through "their" turbines.....and our Public Utility service commission will OK it.
 

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Discussion Starter · #19 ·
Gunpowder River is a typical example of what would have happened if the dams were not on the Susquehanna. At one time, Joppa Town was a major tobacco export center with ocean going ships trading there. Now the head of the river is all but impassable except for the dredged channel. Yes, the sediment would come down with each storm but each storm would add its on thickness of sediment and over time the area would silt in and become a tidal wetlands. To say the area survived sediment before the dams were built ignores the fact that the watershed has undergone vast changes in the last 100 years with erosion and runoff events.
 
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