The lingering issue of the millions of tons of sediment trapped behind Conowingo Dam – and what should be done about it – was a major point of discussions Wednesday during a public information session at Harford Community College on the re-licensing process for the hydroelectric dam on the Susquehanna River.

The Federal Energy Regulatory Commission is in the process of reviewing the permit the dam's owner, Exelon Power, has to operate the facility; the permit is up for renewal in 2014.

In the past, the permitting process has resulted in the dam's owners being required to install fish lifts as part of a larger program to restore runs of American shad in the Pennsylvania portions of the Susquehanna River.

In recent years, concerns have been raised about the potential impact on the Chesapeake Bay if the deep beds of sediment that have settled upriver from the dam ended up being washed out by a major flood.

"The sediment I see as the most serious issue," George O'Donnell, a former Queen Anne's County commissioner and waterman, said. "It has blanketed the Upper Bay and taken us out of the shellfish industry."

A major flood in 1972 resulting from Hurricane Agnes is regarded as an example of the kind of damage that can be inflicted on the Bay when years, or even decades, worth of sediment trapped behind the dam ends up being washed into the Chesapeake in a matter of a few days.

A display showed how the Conowingo Pond, the huge impoundment behind the dam, has nearly reached its capacity to hold the sediment that has been collected in the pond since 1929. Recent studies have estimated the pond has reached at least 86 percent of its capacity to hold sediment.

Many affected

About 50 people attended Wednesday's information session, facilitated by the Maryland Department of Natural Resources and the Maryland Department of the Environment.

Among those present were advocates for the environment, for watermen and for the communities around the river and the Chesapeake Bay.

Natural Resources Secretary Joe Gill opened the two-hour session with brief remarks, introducing the representatives of the multiple agencies which are part of the re-licensing process, which has been in effect since 2009.

"We are basically in the process of coming to the end of the formal filings . . . the purpose of tonight is to present information to the public," Gill said after delivering his remarks.

Officials with Exelon, which owns the 85-year-old dam, have applied to FERC to renew their license to operate the dam and the hydroelectric energy generating plant.

The current license expires Sept. 1, 2014. Exelon is seeking a 46-year renewal..

"Any agency that you could think of that has an interest in the Conowingo Dam has been involved [in the re-licensing]," Shawn Seaman, program manager with DNR's Power Plant Research Program, said.

Seaman said the re-licensing process takes about five years, and Maryland officials have recommended to the FERC that Exelon complete 32 studies related to various aspects of the dam and its impact on the environment.

He said the state used those studies to "come up with our list of issues that we're trying to address."

Water quality concerns

Seaman said the "broad categories" of issues include water quality and sediment, fish passage through the dam – Conowingo Dam has two mechanical "fish lifts" designed to get fish over the dam when they are swimming up the river – water flow and debris management, and recreation and land use.

Expressing a strong interest in the issue of sediment trapped upriver from the dam, a group of at least 20 people gathered around Lee Currey, director of the MDE's Science Services Administration, Bruce Michael, director of the DNR Resource Assessment Service and Mike Langland, a hydrologist for the U.S. Geological Survey.