DARLINGTON — Experts told Sen. Ben Cardin that rivers and streams in the watershed above the dam are responsible for about 80 percent of the sediment flowing into the Chesapeake Bay via the Susquehanna River.
Cardin, D-Md., is chairman of the Senate Water and Wildlife subcommittee. He held a congressional field hearing May 5 at the Conowingo Dam Visitor Center. Col. J. Richard Jordan III of the U.S. Army Corps of Engineers' Baltimore District and Genevieve Pullis LaRouche with the U.S. Fish and Wildlife Service Chesapeake Bay Field Office represented federal agencies.
Donald Boesch, University of Maryland Center for Environmental Science president; Exelon Corporation Vice President of Environment and Safety Vicky Will; Secretary of the Maryland Department of Natural Resources Joe Gill; and Mayor Richard Gray of Lancaster, Pa. spoke for other stakeholders.
The public was not allowed to comment during the hearing.
Jordan said preliminary Corps of Engineers' study results indicate sediment and nutrients scoured from behind the dam during storm events will have to be addressed to meet Bay water-quality goals. But overall, about 80 percent of sediment pollution downstream of the dam comes from high river flows upstream, officials reported.
Sediment picked up from the Conowingo reservoir is about 20 percent during a typical storm.
“The study reaffirms the need to implement the states’ Clean Water Blueprints to restore the Chesapeake and its tidal river,” Chesapeake Bay Foundation Senior Water Quality Scientist Beth McGee said.
“I’m not convinced it’s time to abandon the issue of sediment behind the Conowingo Dam, but we still need more information,” Cardin told reporters after the meeting. “This hearing today reinforces the need to take a comprehensive approach to improving the water quality in the Bay.”
The hearing lasted nearly two hours. At stake is Exelon Corporation's renewed license for generating hydroelectric power at Conowingo. The current license expires this year.
The renewal is in the hands of the Federal Energy Regulatory Commission. The FERC must consider potential environmental effects and can require Exelon to minimize impacts as a condition for renewal.
Attorney Charles “Chip” MacLeod, who represents the eight-county Clean Chesapeake Coalition, questioned some of the testimony.
“I don’t know how they arrived at the 20 percent figure for sediment coming from behind the dam during a storm event,” MacLeod said. “I’ve always heard much higher numbers.”
He questioned the cost Army officials set on dredging built-up sediment. The reservoir above the dam is a 14-mile-long sediment trap. It has been collecting nutrients, silt and other contaminants for more than 80 years, and getting shallower with time.
It is now nearly full.
At “dynamic equilibrium” it still collects sediment on a normal day. Storms, however, will scour off a layer and send it downstream along with sediment from Pennsylvania and New York that is carried along by high water.
Jordan testified May 5 that dredging could carry a price tag of $3 billion, plus $250 million to maintain it.
“We don’t think that is cost effective,” he said.
DNR Secretary Gill held up a satellite photo during testimony. It showed heavy sediment in the Potomac and Rappahannock rivers on the western shore as evidence that all sediment does not come from the Susquehanna River.
Steve Hershey, Republican state senator from District 36, wants more answers.
“We still have a number of scientists who can’t agree,” he said. “It seems logical that if you expand the reservoir above the dam to hold more sediment from flowing over the dam, the need to dredge below the dam would not be as great.”
A joint statement by Maryland Department of the Environment Secretary Robert Summers and Gill was released after the hearing. They said, “The key to restoring the Bay lies in reducing pollution from sources throughout each local watershed — following their Watershed Implementation Plans.”
LaRouche testified for updated and expanded fish ladders to help fish travel upstream to spawn.
Cheryl Mattix of the Cecil Whig contributed to this story.