A resolution in the Maryland General Assembly urging the federal government to help solve the problem of sediment buildup behind the Conowingo Dam was recently passed unanimously by the Senate Education, Health, and Environment Committee.
The dam is located about 10 miles north of the Chesapeake’s Bay northern end on the Susquehanna River, the largest source of fresh water into the Bay. For decades, the dam has been trapping some dirt and pollutants flowing down the river, thus helping to reduce the pollution in the Bay. But now the reservoir behind the dam is filling up with sediment. This poses a serious problem, because large storms flush large amounts of sediment and phosphorus pollution from behind the dam, mudding the nation’s largest estuary.
A resolution proposed by state Delegate Steve Schuh of Gibson Island and state Senator Bryan Simonaire of Pasadena urges Congress to approve a plan by the U.S. Army Corps of Engineers to dredge sediment from behind the dam. The full Senate is expected to vote on the resolution soon, and the House is also expected to take action.
The Chesapeake Bay Foundation has been engaged for many years in studies of the sediment problem at the Conowingo Dam, including the impact of phosphorus flowing over the dam on the low-oxygen “dead zones” in the Bay. And CBF intervened in a Federal Energy Regulatory Commission relicensing procedure for the dam, to make sure that the water quality issues spilling from the dam are addressed. CBF is also pushing for improved passage of fish up and down the Susquehanna River.
“While there have been a number of potential solutions to the sediment and associated phosphorus (pollution) issue identified, dredging seems to have high cost and low environmental benefit compared to other potential offsets that could be accomplished throughout the lower Susquehanna watershed, at least for addressing impacts to the dead zone,” CBF Maryland Senior Scientist Doug Myers wrote to the state Senate committee.
“However, CBF is convinced that if dredging sediments within the reservoir becomes part of a suite of mitigation requirements and Bay management measures that are shared goals, it may be appropriate to cost-share those expenses between the applicant and several levels of government including the federal government, which would require congressional authorization and appropriation,” Myers wrote.
By Tom Pelton
Chesapeake Bay Foundation
(Photo of Conowingo Dam from UMCES)