Last week, appearing before the Eastern Shore delegation, the then acting secretary of the Maryland Department of Environment (MDE), Ben Grumbles, clarified a controversy that has raged the past few years ever since Maryland established Total Maximum Daily Loads (TMDLs) to meet federal guidelines for the water quality of the Chesapeake Bay.
While acknowledging that the sediment trapped behind the Conowingo Dam in northeast Maryland and deposited in the Bay during heavy storms is a concern, Mr. Grumbles said it is not the only one.
And I would say not the most serious one facing the fragile state of the Bay’s health.
Mr. Grumbles simply said this: many different sources, point and non-point, inject nitrogen and phosphorous within Maryland and require close attention, unpolluted by the noise produced by some that Conowingo Dam is the main culprit behind the Bay’s poor water quality.
Since the Conowingo Dam sediment became a rallying call for claims it was the principal cause of Bay pollution, I always thought this opinion was flawed, if not rather simplistic. I wondered how other sources of damaging particles could be ignored, or at least considered secondary.
Mr. Grumbles, now confirmed as MDE secretary, provided a large dose of common sense.
A study called the Lower Susquehanna River Watershed Assessment (LSRWA) produced in November 2014 in large part by the U.S. Army Corps of Engineers, found that the sediment behind the dam is not causing most of the Bay’s pollution. It’s the nutrients attached to the sediment particles that pose the most severe challenge.
Science-based facts gathered independently speak loudly and convincingly.
While the Susquehanna Dam has reduced ability to trap sediment—and that is concerning—the bulk of sediment and nutrient pollution to the Chesapeake Bay from the Susquehanna River, even during hurricane conditions, emanates from several upstream sources, according to an official with the Corps of Engineers. These sources include agriculture, urban and suburban run-off, floodplains and erosion caused by uncontrolled stormwater runoff.
While the Conowingo Dam has become a touchstone for animated debate, all of us who love the Bay should take a deep breath and follow the science. The Bay’s health depends on rational research and rational actions.
That’s what Ben Grumbles said in so many words. My take: don’t be distracted by a controversy that detracts from a diagnosis that demands analysis of the nutrients and phosphorus entering our Bay from many sources.
A two-year study already undertaken by Horn Point Lab in Cambridge will build on the Corps of Engineers’ investigation of the impact of the Lower Susquehanna River Watershed. It is designed to help policymakers select best management options to reduce the onslaught of sediment and nutrients during heavy storms
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According to Horn Point Lab, part of the University of Maryland Center for Environmental Science, “research will measure how much phosphorous and nitrogen is attached to sediment particles that go over the dams and determine the fate of these sediments and associated nutrients in the Chesapeake Bay.”
The results will be telling.
Steve Payne says
It’s true that most of the sediment and pollution emanates from upstream sources but that’s why the trapping capability of the dam needs to be maintained.
joe diamond says
Steve,
There are two terms that I have not seen used much in this discussion. Sediment and pollution are not interchangeable. I am not an expert but I watch for an explanation of the following. While discussing pollution it seems to me there are two aspects to be considered.
SUSPENSION = stuff mixed in a liquid……like sediment, which is soil that has washed into the river. This would include clay (fine particles), sand (bigger particles) and loam (organic materials) along with gravel of different sizes. The important consideration with a suspension is that IF it is allowed to stand long enough………behind a dam or in a lagoon……the heavy stuff settles to the bottom or float. That is the trapping capability you mentioned.
What seems to be left out is the conversation is the other term.
SOLUTION = chemically bonded materials in a liquid. Solutions alter water in ways that make water treatment necessary. Water can be clear but contain all manner of chemical pollutants. So when the chemicals from farm runoff (mainly fertilizer) and chemicals from roads (mainly rubber & petroleum) plus industrial runoff (don’t ask) , when these dissolve in the river what comes down to the dam is no longer water. It will, however, still run the generator the dam was built to operate.
Some dissolved chemicals can be ignored because they have no effect. Others can be diluted until their effects are no longer significant. Some must be removed by a specific process. Probably much more to this part.
I think this is what the article is saying………..What nobody seems to be able to agree upon is how to prevent this and who pays for it.
The only innocent party (my opinion) is the dam. It is inert. If it had never been built the identical problem would still be with us. The pollution would be much farther down the Bay.
Dredging behind the dam (increase trapping capability) might be possible but that is not a complete remedy (didn’t want to say solution). I can’t begin to imagine how to mitigate the “associated nutrients.”
So too I watch.
Joe
Steve Payne says
Joe,
No one that I’ve read ever said it was a complete solution and you’re correct that sediment and pollution are different things. Both bad. The dam traps sediment and is almost full now. It has been determined that the sediment trapped behind the dam is a danger and now a study is being done to determine how much of a danger it is. In addition to that some pollution is attached to or mixed in with the sediment and hopefully the study will shed some light on that too. All I’ve ever said is that both are problems.
I don’t think the dam owner is totally innocent. They’ve received the benefits of the dam that they built and should be responsible for at least some of the maintenance. I’ve built sediment control ponds before and I had to maintain them. Even had to post a maintenance bond prior to getting permits.
joe diamond says
Steve,
Interesting question! The damn builders / owners did benefit from the structure and the electricity they have been selling. Their intention for the pond behind the dam was to assure a constant supply of liquid (water) to run their hydroelectric plant. The sediment, nutrients and debris entered the river upstream due to the actions or inactions of others, damaging the dam operators.
At some point they are going to have to do something to dig that stuff out or the hydroelectric plant will stop working. So it is in their best interest to do something. At the same time others down stream want whatever it takes to stop the flow of gunk into the Bay. They are not as interested in who fixes the problem as they are in how soon it can happen.
Wonder what it would take to get a slurry pump system going to get the sediment out of the basin and into a (hydroelectric) dewatering station and out of the area (on the trains nearby?).
I always wondered how responsibility for sediment control ponds worked. During construction it is obvious…….but as the project is accepted by the customer, at what point can the builder get clear of maintenance of runoff & sediment control? I saw large construction jobs in the 50s with NO sediment control….that material has choked the Anacostia River. Anyhow, could sediment control rules be applied to the Conowingo Dam?
Joe
Steve Payne says
Joe, The sediment control ponds I built were temporary. Once the project was completed and all permits released by the County or City then we could remove them Of course, we had to seed or sod the area prior to that. I did have one pond that the county decided to keep because it was acting like a storm water management pond in addition to a sediment control pond. The county just took title to that one and released us. The latter is sort of what the dam is doing. SWM and sediment control. The only reason I think they should be at least partially responsible is that I believe that they had to anticipate this type of thing happening and yet did no real maintenance. Once the new study is complete I think they’ll figure something out.
Right now there is so much uncertainty and politics involved it’s at the right spot. Let them finish their study and make recommendations and go from there.
Steve
Gren Whitman says
After two years and over $101,000, Frederick County is leaving the “Clean Chesapeake Coalition.”
According to Frederick News-Post, “Frederick County Executive Jan Gardner says county has gotten little return on its investment.”
joe diamond says
Gren,
Good catch.
Fredrick County must realize they will never see a return upon investment. But if they reject the nice guy approach I bet someone will calculate the damage their point-no-point pollution has damaged the Bay. They have been in bed with Ft. Detrick where the government has worked on chemical weapons & other unnamed nasty stuff. Their Monocacy River drains their farms and feeds the Potomac, a Chesapeake tributary. Fredrick County even fronts the Potomac.
Gotta wonder if anyone told them payments to fix the Bay might not work until after the sitting.
joe