'Clamming' operations continue at Conowingo Dam to remove river debris

Efforts continue at Conowingo Dam to remove the unusually large river debris field that has piled up this winter behind the Harford County side of the dam.

The collection of wood, plastic, metal and other detritus coming down the Susquehanna River from the north is the most in 20 years, according to a spokesperson for Exelon Generation, the hydroelectric dam’s owner.

Officials from Harford and Cecil counties have been monitoring the situation amid posts on social media raising concerns that some ot the junk will eventually get through the dam and flow downriver into the Chesapeake Bay, something the dam’s owner says is unlikely, however.

A contingent from Cecil County government, led by County Executive Alan McCarthy and Director of Administration Al Wein, visited the dam on March 8 to observe cleanup operations, which Conowingo officials refer to as “clamming,” using a crane-mounted grappling, or clamshell, bucket to pick up the debris and place it in large dumpsters, which are then trucked away to disposal sites.

Harford County government is aware of the “extraordinary” debris situation at Conowingo, spokesperson Cindy Mumby said earlier this week, while noting it is Exelon’s responsibility to deal with it.

“We expect them to follow through with their plan,” Mumby said.

“At Exelon Generation, we are committed to protecting the natural environments we share with our surrounding communities through a variety of sustainable practices, including debris removal around the Conowingo Dam,” Deena O’Brien, Exelon’s Mid Atlantic regional communications manager, said in a written statement this week.

O’Brien noted that the dam traps debris from the 27,000-square-mile Susquehanna River watershed covering parts of New York, Pennsylvania and Maryland.

“In 2018, we’ve seen the largest volume of debris flowing downriver in 20 years because of winter storms, ice flows on the Susquehanna River, and heavy rains that affected the entire watershed,” she wrote. “We share all concerns about the debris and its potential impact on communities, the health of the river and the Chesapeake Bay.”

Dam personnel will continue to follow a debris management plan, according to O’Brien, who said they have cleared enough debris since he beginning of the year to fill 18 20-cubic-yard dumpsters.

“Although the process takes time, we have crews operating overhead cranes and grapple devices to clear debris from the river as safely and efficiently as possible,” she wrote. “When safe, we will launch debris skimmer boats to assist with cleanup.”

The Cecil County officials visit to the dam last week was prompted by a number of photos and comments circulating on social media showing mounds of refuse filling the water, and an outcry from the public about what is being done about it, according to Jennifer Lyall, public information officer.

“Also concerned about environmental issues downstream, McCarthy contacted Exelon for some answers, and with good reason,” Lyall wrote in a news release. “Looking to your right as you drive across the dam into Harford County, gives you a live, up-close look at the pond behind barrier and what Exelon has to contend with, and it's not pretty.”

Lyall said the group, which in addition to McCarthy and Wein included strategic consultant Dr. Carl Roberts and Department of Emergency Services Chief Richard Brooks, watched the removal operation, which included fishing out a large number of large blue plastic drums that appeared to have come from a floating pier that broke up at some unknown location upriver.

The group conferred with the dam’s general manager, Bryan Bennett, who Lyall said explained that the dam had already 22 days of crest gate openings since Jan. 1 because of melting ice, precipitation and upriver flooding. A more typical flow in the January and February period would result in zero to 10 days of gate openings.

According to Lyall, Bennett emphasized the dam’s role in trapping the debris field is actually beneficial, because it makes removal possible. Once the dumpsters are filled from the clamming operation, they are taken to Hopkins Cove, which is north of the dam on the Harford side of river. There the debris is sorted for recycling or landfill disposal. The majority is wood – trees, limbs, stumps – which is chipped and then taken off-site.

Lyall said both Bennett and O’Brien explained that clamming operations and launching the skimmer boat were delayed because of the high winds from the nor’easter the first weekend in March, which also caused more debris to come downriver. She said Bennett told the group the boat isn’t very efficient with such a large amount of debris, anyway, and the crane couldn’t be operated in high winds.

He also told the group Exelon also has to use divers to clear the worst of the debris away from the trash racks that protect the head gates prior to opening.

"This visit was very educational and I understand what's going on better now," McCarthy said in a statement. "No one wants to see the debris floating in the water, but we also do not want to risk any injury; when conditions become safer, the clean-up will commence. The fact that it all collects there really is a good thing; otherwise, it would be going down the Susquehanna in large volumes with every opening."

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