When looking at the Conowingo Dam, people see many different things.

Many see an awe-inspiring concrete monolith, standing almost 100 feet high and stretching almost a mile — 4,648 feet to be exact — across the Susquehanna River. It even supports a major highway, U.S. 1, which runs across its top.

Others see an obstruction that has closed almost all of the largest river on the U.S. East Coast to migratory fish since it was built in 1928.

Some see a source of clean energy, which produces an average of nearly 1.9 million megawatt hours of electricity annually.

Increasingly, many see a barrier that keeps two-thirds of the sediment and a third of the phosphorus coming down the Susquehanna from entering the Bay, but is rapidly losing its ability to do so, and becoming an increasing threat to the Chesapeake's health.

But in the coming year, what a number of people see is a rare opportunity to influence a host of issues affecting the Bay and its largest tributary.

That's because the 30-year license Exelon Generation has to operate the dam expires Sept. 1, 2014. Agencies and organizations hope to have the Federal Energy Regulatory Commission include stipulations in any new license that address a suite of concerns.

The relicensing process has significant ramifications for the Bay and its largest tributary, although relatively few people are aware of it. Depending what type of deal is struck, it could influence everything from how much debris and sediment gets downstream to how many river herring, shad and eels — all of whose populations are at historic lows — get upstream.

"This is the biggest issue for the Chesapeake Bay," said Michael Helfrich, the Lower Susquehanna Riverkeeper.

While others may not go quite that far, it is clear that decisions made in the coming year, as serious negotiations take place, will have profound impacts for the lifespan of the next license, which could be anywhere from 30 to 46 years.

"This is in some ways a once-in-a-generation opportunity to try to get a better balance between energy production and the other benefits we get from these hydropower dams with the environmental conditions that result from their operation," said Mark Bryer, director of The Nature Conservancy's Chesapeake Bay Program.

The process has actually been under way for several years. Exelon submitted its pre-application in 2009. Since then, Exelon officials say they have spent roughly $15 million on relicensing issues, including 32 studies covering a variety of resource issues related to dam operation, from the types of flows needed to attract migratory fish upstream to an assessment of recreational needs in its vicinity.

In August, Exelon submitted its formal license application to FERC, including its recommendations about how to handle various issues based on those studies. The commission has been reviewing the application and, when it's satisfied, will issue what's called a Ready for Environmental Assessment decision. That's expected early in 2013, and will launch a final yearlong environmental review.

Coinciding with that review is a formal negotiation process between Exelon, state agencies from Maryland and Pennsylvania, and federal resource agencies. Negotiators will try to reach agreement on how to handle a variety of resource issues and have those conditions incorporated in the new license.

But FERC doesn't necessarily have the last word. Under Section 401 of the Clean Water Act, Maryland needs to certify that the project complies with its water quality standards. FERC can't issue the license (although it can issue one-year extensions) unless the state issues the certification.

That doesn't give the state negotiating power over such things as improved recreational access. But state officials insist it does give them broad leverage over anything dealing with water quality — even on actions aimed at increasing populations of water-filtering mussels.

"Section 401 Water Quality Certification is a very powerful tool," said Guy Alsentzer, staff attorney for the Lower Susquehanna Riverkeeper. "A state can literally deny the issuance of any permit for any type of facility that would give a discharge to a waterbody."

There's another backstop as well. The Lower Susquehanna Riverkeeper and other organizations have filed as intervenors in the relicensing process, something that gives them standing to challenge the license in court.

But there is a limit to what they can seek. At some point, the new license wouldn't be worth the expense. "There is only a finite amount of money available that they are going to be able to deal with," said Bruce Michael, who heads the Resource Assessment Service of the Maryland Department of Natural Resources. "They can't just do everything we ask, because it would cost hundreds of millions of dollars. They don't make hundreds of millions of dollars."

Still, Exelon officials say they are expecting to make significant environmental investments under the conditions of any new license, which is why they are seeking a 46-year license. Its last license, and those of other upstream dams, spanned 30 years. "There's a correlation between PM&E [environmental protection, mitigation and enhancement] measures that are negotiated and the length of the license," said Colleen Hicks, who is working on relicensing for Exelon. Although those negotiations are just beginning, she said, "we expect the level of investment will be enough to get us a license of that term."

Here's a look at the key issues to be negotiated:


The license agreement has taken on even greater importance after the release of a U.S. Geological Survey report last summer that showed increasing amounts of phosphorus and sediment were starting to pass by Conowingo during high flows as the dam's reservoir nears its storage capacity. If nothing is done, gradually increasing sediment and nutrient loads from the Susquehanna could make it more difficult to achieve Bay water quality criteria. "Managing sediment and nutrients coming over the Conowingo Dam is our highest priority issue," Michael said.

Agencies from Maryland and Pennsylvania have been working with the Army Corps of Engineers on a study to find solutions, which could be hugely expensive. It's unclear what the options will be, and no one suggests that Exelon should be responsible for sediment that originates far upstream. But, officials say it's important that Exelon be a player in any solution, especially if recommended actions — such as any potential dredging — would require changes in dam operation.

"They need to be a player in the game," said Shawn Seaman of the Maryland DNR's Power Plant Research Program, who is coordinating the state's review of the process. "Are they the only player in the game? No."

There's also a second sediment issue. Much of what passes the dam is fine silt and clay — things that are particularly bad for water quality in the Bay because they stay suspended in the water, blocking sunlight to the bottom.

But some biologists believe the river below the dam is "starved" for heavier sediments, such as sand, which is largely trapped in the reservoir.

The dam has been in place so long that no one knows with confidence what downstream habitats were once like, but biologists think there was probably more sand, at least in places, that provided habitat for freshwater mussels and other species.

They are interested in seeing if some of the sand trapped in the reservoir could be transported around the dam to create habitat. Unfortunately, that heavy sediment tends to be the farthest away from the dam, so it's more problematic to get it around the structure and downstream. And it's unclear whether it would stay put: Downstream river levels fluctuate greatly as the dam alternately stores and releases water, and the intermittent flows could erode the sand.

Fish Passage

The Conowingo Dam, located just 10 miles upstream from the Bay, has essentially closed the largest river on the East Coast to migratory fish. A huge fish ladder was opened at Conowingo in 1991 to lift American shad and river herring over the dam so they could return to their historic spawning habitat. But the elevator has never been as effective as biologists hoped. And migration is further hampered by three upstream dams; few fish make it past all of them in a typical year.

State and federal officials have worked in recent years to negotiate improved fish passage at all of the dams on the river. As part of the relicensing, they want to secure fish passage improvements at Conowingo as well. This could include changes to the existing fish lift and flow modifications to better attract shad to the lift. They also want to reduce fish mortality.

"We haven't had much success over the years with American shad, and we're trying to increase the passage as much as we can," Seaman said.

In addition, negotiators want to get American eels upstream, which the fishlift is not designed to handle. Eels migrate along the side of the river — not in the middle where the lift is located. Eels have become a high priority because they are needed to bolster populations of water-filtering mussels upstream. One option to get them above the dam, which Exelon has supported, is simply to capture eels and truck them around Conowingo and other dams on the river; a pilot project in the past several years has successfully caught large numbers of eels and trucked them upstream.

Also needed, biologists say, are improved methods of getting those species back downstream so they are spared the peril of passing through the dam's turbines. That's especially critical for eels, which can be 3 feet long when they migrate out.

Freshwater mussels

Biologists and water quality managers alike are interested in rebuilding freshwater mussel populations on the Susquehanna. Recent research indicates that American eels play a critical role in the reproduction of Eastern eliptio mussels upstream; eels serve as a temporary host for the parasitic larval stage of the mussels. Without them, the larvae don't survive to become small mussels.

Eastern elliptios are the most common mussel species in the adjacent Delaware River, but their population in the Susquehanna is depleted, and those that remain are mainly old. Biologists think rebuilding the upstream eel population is the key to restoring the mussel population — and a potentially large water-filtering capability in the river.

"Mussels are like oysters," Michael said. "They filter the water. The greater the mussel population, the more they are filtering, and the more they clean up the water and reduce the sediment."

Biologists are also interested in rebuilding populations of other mussel species downstream of the dam. A combination of factors, such as rapidly changing river flow levels related to dam operation and the loss of sandy sediment for them to burrow into, likely contributed to their decline. Negotiators will seek changes that would help those mussel populations as well.


Officials would like to see improvements at some of the access sites Exelon maintains in the vicinity of the dam and reservoir. But the top recreation issue for many is reopening the catwalk at the base of the dam, which was closed to the public after the Sept. 11, 2001, terrorist attacks.

At public meetings, restoring access to the catwalk has been a priority for anglers. "That is the place to catch stripers," said Riverkeeper Helfrich. "I had a whole group of older fishermen come to me and say that their fishing experience has been diminished. Exelon does not own the river. People own the river."

Exelon officials say they built a fishing wharf near the dam to provide new fishing opportunities. Hicks said the cost of reopening the catwalk and maintaining security would be "prohibitive."

Debris Management

During large storms, huge amounts of debris go over the dam and can be washed far down the Bay. Exelon already conducts efforts to collect trash that builds up behind the dam, but officials want to see if there is more that can be done to keep debris from getting downstream.

Rare, threatened & endangered species

A number of species that are rare, threatened or endangered may inhabit the area below the dam, including Atlantic and shortnose sturgeon, one species of freshwater mussels and others. Negotiators will seek to mitigate any dam operations that could affect those species.

Biologists continue to search for the Maryland darter, which is only found in streams below the dam, but it may be extinct. "If we find it, we would want to make sure the dam operation isn't doing anything that would negatively impact the species," Michael said.

Also of concern is Maryland's only population of map turtles, which lives below the dam. The turtle requires basking habitat, such as large rocks, but rapidly changing river levels caused by dam power generation frequently results in those habitats being inundated. "We've taken that pretty seriously, and are trying to think of some low-cost options, like floating habitats which can provide them a place to bask," Seaman said.

Land Conservation

Exelon, like other dam owners on the river, owns large tracts of land near the dam and around its reservoir — 11,700 acres in all. In its recent relicensing application, Exelon is seeking to remove about 2,000 acres of land from the project boundary, which would remove it from FERC control, although they say they have no plans to sell the land.

If Exelon were to get rid of any land, conservation groups would like to see it transferred to county, state or federal agencies for conservation and recreation purposes.