Advertisement

Conowingo Dam fish-lift overhaul urged to restore Susquehanna's shad, eels

Federal wildlife officials are calling for Exelon Corp. to overhaul its fish lifts at Conowingo Dam, arguing it's the only way to revive the Susquehanna River's depleted stocks of the iconic American shad, eels and other once-important fish.

In comments submitted to the Federal Energy Regulatory Commission, the U.S. Fish and Wildlife Service recommended the lifts be rebuilt and enlarged as a condition of renewing Exelon's license to generate hydroelectric power at Conowingo.

Advertisement

The service also wants the power company to help more eels get upriver — by truck for now.

Rebuilding the dam's fish lifts could cost millions of dollars. Exelon is reviewing the wildlife service's prescription for improving fish passage, said Robert Judge, a spokesman for the Chicago-based parent of Baltimore Gas and Electric.

The service's proposal comes after years of negotiations between Exelon and officials from Maryland, Pennsylvania and federal agencies over the dam's relicensing, which has been hung up in part by debates over how to deal with a buildup behind the dam of bay-fouling sediment and nutrient pollution washed down the river.

The company's license to operate Conowingo expired last year, but the federal commission has extended the permit while the parties attempt to work out their differences over the sediment buildup, fish passage and other issues.

"We've reached a crucial period," said Genevieve LaRouche, supervisor of the wildlife service's Chesapeake Bay field office. "It's a 46-year license. It's kind of a once-in-a-lifetime opportunity to do something."

LaRouche said the service hasn't costed out the upgrades yet. But state and federal officials have previously said current fish passage facilities could be tweaked for less than $1 million, while replacing both fish lifts could run $24 million or more.

In earlier talks, Exelon had proposed making only minor adjustments in its current fish passage operations, arguing that upgrades to the lifts weren't warranted.

The company has 30 days from the filing to either accept the wildlife service's proposal or offer an alternative. If Exelon challenges the service's plan, the parties' differences would be hashed out in a trial-type administrative hearing.

A Maryland official endorsed federal officials' plan for getting more fish and eels upriver, though he noted it's just one of many issues tangled up in the relicensing of the Conowingo Dam.

"We're comfortable with what they're putting forward," said Bruce D. Michael, director of resource assessment for the Maryland Department of Natural Resources.

But Michael stressed that the Hogan administration's top priority is reducing the threat to the bay's water quality posed by the nutrient-laden sediment trapped behind the dam.

Big tropical storms and heavy spring flows stir the muck up from the river bottom, periodically fouling the upper bay. A study indicated the buildup could prevent upper bay waters from being completely cleaned up, despite extensive efforts to reduce nutrient and sediment pollution throughout the watershed.

American shad, river herring and American eels are all far less abundant in the bay's largest tributary than they were before Conowingo was built in 1928. Shad and herring once swam far upriver every spring to spawn, and in the 18th and 19th centuries fishermen netted them by the millions. Elvers, or small juvenile eels, also thronged the river as they completed a long migration from their spawning grounds in the Sargasso Sea.

Shad once played a prominent role in the Chesapeake Bay region's culture and economy and eels help keep the water clean.

Advertisement

While historic overfishing also decimated the fish species, the service attributes their declines in the Susquehanna largely to the barriers posed by Conowingo and three other hydroelectric dams upriver. Aided by commercial harvest moratoriums imposed decades ago, shad have rebounded in the Potomac and some other rivers not impeded by dams, officials note.

In earlier attempts to reverse the declines, Conowingo's operators built lifts in 1972 and 1991 to hoist migrating fish up and over the 94-foot dam. The elevators seemed to be working for a while, and the number of American shad passed upriver peaked at 193,000 in 2001. The tally has been declining since, with a record low of just 8,341 picked up this spring.

Wildlife officials say the lifts never performed to expectations, and want them retooled and replaced to accommodate more fish — with a goal of handling up to 5 million American shad and 12 million river herring annually one day.

But given the meager numbers showing up in recent years, the service proposes to expand gradually. Initially, Exelon should alter water flows at the base of the dam to attract more migrating fish to the larger lift, then replace the smaller, older lift on the western bank of the river with a much larger elevator. The proposal calls for ultimately expanding the larger lift as well, adding a second hopper to double its fish-carrying capacity.

The new lift on the western bank also would be designed to help eels make it upriver, either using the lift or by trapping them and trucking them to various release points, as the wildlife service is doing now. Unlike shad and herring, eels are showing a modest resurgence in the river, with about 65,000 tiny elvers collected so far this year.

"This year's not living up to last year, but it's still pretty good," said Mike Mangold, assistant fisheries project leader with the wildlife service, on Wednesday as he and biologist Jennifer Malavasi checked on about 100 elvers lurking in their holding tanks.

Environmental advocates backed the federal fish passage plan, though one said he wanted to see even more done for eels.

Michael Helfrich, the lower Susquehanna riverkeeper, said he would like a more detailed prescription for spreading eels throughout the lower Susquehanna and its creeks, noting that could help to clean up the bay.

The snake-like fish are hosts for a tiny freshwater mussel that is a prolific filter feeder. The mussels, like eels, have been decimated in Susquehanna waters. Scientists hope that by reviving the river's eels, they can boost the depleted mussel populations and clear up murky water in the process.

William Goldsborough, senior fisheries scientist for the Chesapeake Bay Foundation, said enhanced fish passage might begin to finally restore the river's vitality to what it was centuries ago.

The largest river on the East Coast once supported massive spring spawning runs of shad and herring, Goldsborough said. They were a staple on many a table and "essential parts of American culture for a couple centuries," he added.

"We ended all of that when we blocked the river off early in the 20th century," Goldsborough said.

Advertisement
Advertisement