Neither presidential campaign spent much time discussing the environment, but in this region, the air and water are cleaner, because local efforts reduced vehicle emissions and greenhouse gases, and most wastewater treatment plants operate at the limits of technology. This region also values the Chesapeake Bay, one of the world’s great estuaries, and one that has enormous economic benefits. Among the rivers draining the 64,000 square mile Chesapeake Bay watershed are the Potomac, Rappahannock, York, and James in Virginia, the Patuxent and Choptank in Maryland, and perhaps the granddaddy of them all – the Susquehanna, which begins in New York, but whose major flow is through Pennsylvania.
The Susquehanna is the largest single source of sediment and nutrients to the Bay. Its huge freshwater flow carries nearly half of the nitrogen, and a quarter each of total phosphorus and sediment. That same flow has provided clean, reliable hydropower at the Conowingo Dam, a mile-wide power generating station, which began operation in 1928. Last week, along with other local officials, I toured the Conowingo Dam, and learned a lot more about its value, and its challenges, for the watershed and its residents.
For a structure so large, the approach to the facility is quite surprising – country byways wind through rural Maryland farms. In the parking area were dozens of tripod cameras with long lenses, perched along the riverside bluff. Was there something special going on? Turns out that the Conowingo provides prime breeding, nesting, and foraging grounds for the America bald eagle, and the cameras were focused on birding that morning.
The Conowingo generates enough electricity annually to power more than 160,000 households. Operating under an annual license while its new 46-year license application undergoes review by the Federal Energy Regulatory Commission and the Maryland Department of the Environment, it is Maryland’s largest source of renewable energy and, when compared to coal, prevents 6.5 million tons of greenhouse gas emissions each year. The dam’s owner, ExelonGeneration, also is working with the U.S. Fish and Wildlife Service to trap and transport American shad upriver. The fish lifts are enormous, and assist in the passage of more than one million native and migratory fish each year.
For many years, Bay restoration discussion focused on the need to dredge out toxic sediments trapped in the reservoir behind the dam, to prevent them from leaching into the Bay during heavy storms. It was a surprise, then, when a 2014 U. S. Army Corps of Engineers report found that removing a significant amount of sediment via dredging would have little long-term impact to the health of the Bay. Reducing nutrient and sediment loads from upstream is recommended. That approach is not surprising – it’s what all river basin jurisdictions in the watershed have been struggling with for decades.
As noted earlier, the Susquehanna has a significant effect on the health of the Bay and I was prepared to be highly critical of the Conowingo Dam operation. What I found was a well-built and well-run hydro-electric power station, a critical asset to the eastern U.S. power grid, carefully regulated by the state and federal government. Challenges, like sediment, remain, but at Conowingo, environment and economy are intertwined; there are no easy answers.
Penny Gross is the Mason District Supervisor, in the Fairfax County Board of Supervisors. She may be emailed at email@example.com.