They peppered the officials with questions and comments about sediment; representatives of Chesapeake Bay watermen said the sediment and silt that comes out of the pond during major storms smothers shellfish in the upper portion of the Chesapeake below the dam.

Capt. Robert Newberry, of the Harvesters Land and Sea Coalition, who is also a former waterman and lives in Queen Anne's, said he was making a "good living" about seven years ago catching oysters.

"This sediment coming out the Conowingo Dam took an industry that was producing 50 to 70,000 bushels of oysters a year to zero now, absolutely zero," he said.

Charles D. "Chip" MacLeod, a Chestertown attorney who represents the Clean Chesapeake Coalition, an organization of the governments of Allegany, Carroll, Cecil, Caroline, Dorchester, Frederick and Kent counties, said efforts to clean the river and Bay below the dam are misguided.

"We're spending all this money trying to save the Bay below the dam," he said. "It's like a fools errand when this occurs."

Currey and Langland noted the Army Corps of Engineers is conducting a study, called the Lower Susquehanna River Watershed Assessment Study, of sediment movement along the Lower Susquehanna in Pennsylvania and Maryland, specifically in the portion of the river where four dams, including Conowingo, are located.

"That's going to help inform our decision-making process at the department," Currey said.

Big expense

Langland said it could cost "hundreds of billions" of dollars to remove sediment from Conowingo Pond.

Michael Helfrich, a riverkeeper for the lower Susquehanna, said officials must consider the costs of depositing the sediment at a landfill, where they would have to pay by the ton, or of transporting it to a mine out of state, as well as finding a large enough area to dry the sediment out.

He encouraged people to work to develop solutions on how best to use the sediment in a practical and ecological manner.

"We need innovation," Helfrich said. "We have a problem, we have a necessity, now we need inventors."

Kimberly Long, Exelon's senior program manager for hydro re-licensing, said company officials view sediment in the dam pond as "a regional watershed issue."

Long noted the dam is a "receiver" for sediment from a Susquehanna watershed of more than 27,500 square miles.

"Conowingo has been serving as a best management practice for the Chesapeake Bay for over 80 years, in the sense that we've been maintaining sediment that would otherwise pass downstream," she said.

Long said Exelon officials have been working with federal officials, as part of the re-licensing process, by providing information on the state of the sediment behind the dam to assist with the Lower Susquehanna River Watershed Assessment Study.

Long noted sediment can pass through the dam's spillways during storm events as they open to allow excess water, which is carrying suspended sediments, through.

"Exelon is committed to being part of the solution and being involved with other stakeholders that have concerns with sediment management," Long said.

The re-licensing process is expected to continue well into 2014; the agencies involved must submit their recommendations to the FERC by Dec. 15 of this year, and Exelon must file an application with the state for a Section 401 Water Quality Certification by the same date.

Long said the state must then file the water quality certification with FERC, which will then will incorporate it into any operating license that ends up being issued to Exelon.

She said Exelon can operate the dam for one year beyond the date of its current license, under the conditions of that license if there is a delay or if FERC requires the company to do more to satisfy stakeholders.