DC Program Pays Residents to Reduce Stormwater Pollution
The Election and the Bay

Don't Stall Bay Cleanup Over Dam Problem

ConowingoSome elected officials from rural counties in Maryland recently argued that their communities should delay investing in water pollution control projects to clean up the Chesapeake Bay until a solution is found for the problem of sediment buildup behind the Conowingo Dam on the Susquehanna River, the estuary’s largest tributary.

The theory, as voiced by State Senator E.J. Pipkin and others last week, is that all local efforts to reduce stormwater pollution would be effectively wiped out if another big storm flushed a huge slug of pollution from behind the dam in northern Maryland into the Bay, muddying the waters and smothering underwater life.

“Before the state and its counties commit to such heavy expenditures (to clean up local waterways), Maryland should evaluate whether these efforts, in light of the Susquehanna’s polluting potential, will be in vain,” Pipkin said in a press release.

It would make no sense to stall action to meet EPA pollution limits for the Chesapeake Bay based on this fear.  It would be like a man suffering from high blood pressure to suddenly abandon his heart-healthy diet when he learns his wife has a back problem. Yes, the back injury is a serious issue and deserves attention. But for the man to neglect his own health while he worries about his wife will only hurt him, his wife, and their children in the long run. 

It is not productive to throw your hands in the air and cry “Stop everything!  It’s all in vain!” when complex problems like the Conowingo Dam issue arise.  This attitude undermines the careful, science-based plans EPA and the Chesapeake region states have developed for restoring the health of the Chesapeake Bay and its streams and rivers.

There is no reason states and counties in the Chesapeake Bay watershed should not proceed with building stormwater control systems and upgrading sewage treatment plants while engineers simultaneously figure out a solution to the Conowingo Dam’s sediment problem (which they are working on).

Many local waterways, like the Chester River in Senator Pipkin’s district, are not even downstream from the Conowingo Dam –- and their pollution problems need to be addressed, regardless of what happens with the Conowingo Dam.

Here’s the background and the big picture:

Last year, Maryland officials and the U.S. Army Corps of Engineers launched a study of how to solve the Conowingo’s sediment buildup problem.

Historically, the 84-year-old hydroelectric dam in north central Maryland has trapped about two thirds of the 3 million tons of sediment pollution flowing down the Susquehanna River toward the Bay every year, according to the Maryland Department of the Environment (MDE).

But the 9,000 acre pond behind the dam has been slowly filling up with fine particles, dirt and other pollutants. The reservoir’s capacity to catch and hold more sediment will likely be reached in 15 to 20 years, MDE reports.  “At that time, sediment and nutrient inputs to the Bay would increase dramatically, threatening efforts to improve Bay water quality and increase the health of aquatic life,” according to a joint statement by MDE, the Maryland Department of Natural Resources, and the U.S. Army Corps of Engineers.

Large storms have historically stirred up problem with this containment system, scouring up sediments trapped behind the dam, and sending them billowing downstream like giant plumes of chocolate milk. This didn’t happen during Superstorm Sandy last week.  But a year ago, during Tropical Storm Lee, the flood of stormwater sent 19 million tons of sediment through the Conowingo Dam and down the Susquehanna River toward the Bay. In a few days, Lee flushed more than seven times the average annual amount of sediment flowing down the river from 1978 to 2011, according to a U.S. Geological Survey report.

That’s a lot of mud.  Scientists had been concerned that nitrogen and phosphorus mixed in with this muck would create a large no-oxygen "dead zone" in the Bay.  Interestingly, however, the "dead zone" in the Chesapeake this past summer was the smallest on record.

Workable solutions exist for the Conowingo's sediment problems and are being studied by the Army Corps of Engineers,  and Maryland’s environmental and natural resources agencies. 

For example, the dam’s owner, the Exelon power company, has applied to the Federal Energy Regulatory Commission for re-licensing.  In theory, as a condition of relicensing the dam, the federal government could tell Exelon to pay for dredging the pond behind the dam. Perhaps the silt could be recycled to sell in construction materials such as concrete blocks.

Another idea might be to gradually allow some of the trapped particles to flow through the dam during the fall or winter, when the potential for smothering aquatic vegetation downstream is reduced.

While all this is being worked out, other communities in the Chesapeake Bay region should not be distracted or pretend that they also don’t have their own local pollution problems to fix.

We all need to do our share, in our own local streams and rivers, to restore the Bay, a national treasure.

By Tom Pelton

Chesapeake Bay Foundation



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I was not aware of that problem, but I'll check into it.

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