Maryland orders Exelon to shoulder Conowingo pollution reductions

After years of study and haggling over how to deal with the impact of Conowingo Dam on the Chesapeake Bay, the Hogan administration has ordered the hydropower facility’s operator to reduce nutrient pollution passing through the dam on its way down the Susquehanna River — or pay up to $172 million a year for someone else to do it.

The Maryland Department of the Environment announced Friday that it had issued a condition-laden water quality certification needed by the utility before it could receive a new federal license to continue operating the hydroelectric dam. The 59-page document directs the facility’s owner, Exelon Corp., to take a series of steps to help spawning fish over the 94-foot high dam, to produce a more natural river flow and to improve fish habitat and water quality.

MDE directed Exelon, which is seeking a new 50-year license for Conowingo, to make annual reductions of 6 million pounds of nitrogen and 260,000 pounds of phosphorus in the lower Susquehanna below the dam. Those are the amount of nutrient reductions studies have indicated are needed to offset the impact of the dam on Upper Bay water quality. If the company does not make those reductions itself, then the MDE directed it to pay “in-lieu fees” if nothing else is done to reduce the nutrient flows.

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