When the Lion Lays Down with the Lamb . . .

. . . only the lamb is nervous. States to collaborate on implementation plan for Conowingo Dam’s owner, Exelon, will likely be called upon to provide some of the funds for meeting pollution reduction goals

For years, the 94-foot-high Conowingo Dam was considered a “time bomb” looming over Chesapeake Bay cleanup efforts, as it would begin spilling more water-fouling nutrients downstream when its 14-mile-long reservoir stopped trapping pollution.

But that was always considered a problem for the future. So, the challenge of defusing the “bomb,” located on the Susquehanna River in Maryland just 10 miles from the Chesapeake, was punted to the future as well.

“We faced a problem that we didn’t have a solution to at the time,” said Lee Currey, director of the Maryland Department of the Environment Water and Science Administration.

Recent analyses of monitoring data, though, have shown that the bomb actually went off years ago — but not with a resounding boom. Instead, there’s been a gradual increase in the amount of nitrogen and phosphorus swept past the concrete structure as its reservoir filled with sediment and hit a state of “dynamic equilibrium.”

To meet its cleanup goals, the state-federal Bay Program must now figure out how to offset an additional 6 million pounds of nitrogen and 260,000 pounds of phosphorus reaching the Bay each year.

That’s roughly a 2.5 percent increase in the total amount of nutrients entering the Chesapeake. While the percentage may seem small, it would likely require tens — if not hundreds — of millions of dollars to address, on top of a cleanup program already expected to cost billions.

Currey recently worked with a team of state and federal officials that is trying to fix that problem. While some key questions remain unanswered — including how much the additional pollution reductions will cost and when they will be completed — the team recently produced a framework for moving forward, which was accepted by Bay Program leaders in March.

The framework calls for all states in the watershed to work on a new, collaborative watershed implementation plan, or WIP, aimed specifically at reducing enough nutrient pollution to offset the impact of more nutrients flowing past Conowingo.

The WIP will be written by representatives from the six states in the watershed, along with the District of Columbia and Chesapeake Bay Commission — a legislative advisory panel. It will be an addition to the WIP each state has written — and is now updating — to achieve its own share of the nutrient reduction goals that were set in 2010 by the U.S. Environmental Protection Agency through the Chesapeake Bay Total Maximum Daily Load.

Conowingo Dam

But rather than spread the implementation among all jurisdictions, the WIP will target nutrient control actions to areas where they will be most effective in offsetting the dam’s impact — primarily parts of Pennsylvania, New York and Maryland.

If the burden were spread among all Bay jurisdictions, it would require significantly more nitrogen reductions. That’s because reductions from more southern areas tend to be less effective at offsetting the impact of Conowingo, which is located near the top of the Bay. Computer modeling shows the value of geographic targeting: By directing efforts toward areas where they are most effective, Conowingo’s impact can be offset by 6 million pounds of nitrogen reductions versus about 7.3 million pounds if distributed across the whole watershed.
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Exactly how the Conowingo plan will be funded isn’t clear. At least a chunk of the money is expected to come from Exelon, the utility that owns Conowingo, which is seeking a new multi-decade license from the Federal Energy Regulatory Commission to continue operating the hydro facility.

As part of the relicensing process, Maryland must first certify that the dam’s operation will comply with state water quality standards. To make that certification, the Maryland Department of the Environment is likely to require Exelon to address water quality issues in the river immediately upstream and downstream of the dam, but it will also likely have a role in implementing the new WIP. The MDE will make a decision about the certification in mid-May. It won’t be known until then how much Exelon might have to pay toward nutrient reductions.

Exelon's mistake was buying an energy producing asset that has saved the bay countless tons of pollutants for the last 80 years, but which has out lasted it's ability to continue to absorb those nutrients. Holding the dam responsible for the resulting pollution is like blaming wet streets for rain.