Sediment building up behind Conowingo Dam has almost reached the reservoir’s capacity for storage, according to a report released by the U.S. Geological Survey (USGS). The reservoir is considered at its limit for holding sediment when it is half full—at present, it is 92 percent of the way toward this maximum.
Since its construction in 1929, the Conowingo reservoir, along with the reservoirs behind the Holtwood and Safe Harbor dams, has trapped sediment and nutrients as they flow down the Susquehanna River—which provides nearly half of the fresh water that flows into the Bay. According to the report, the ability of these reservoirs to trap pollutants has been steadily declining.
“Storage capacity in Conowingo reservoir continues to decrease, and ultimately that means more nutrients and sediment will flow into the Bay,” said Mike Langland, author of the study, in a release. “Understanding the sediments and nutrients flowing into the Bay from the Susquehanna River is critical to monitoring and managing the health of the Bay.”
Excess sediment can cloud the water and harm underwater grasses, fish and shellfish, while nutrients can fuel the growth of harmful algae blooms and the creation of low-oxygen “dead zones,” which suffocate underwater life. Reducing the amount of pollutants in local waterways is integral to Bay restoration efforts, including the Chesapeake Bay Total Maximum Daily Load (TMDL), or “pollution diet,” which Bay Program partners recommitted to achieving as part of the Chesapeake Bay Watershed Agreement. In anticipation of a decline in Conowingo reservoir’s ability to trap sediment, the TMDL includes a mechanism for addressing any increases in nutrient and sediment pollution caused by a full reservoir.
The report from USGS reiterates the findings of a study by the Lower Susquehanna River Watershed Assessment (LSRWA) team, released in November 2014, which found that the once-effective “pollution gate” is trapping smaller amounts of sediment and nutrients and, during large storms, sending more of these pollutants into the Susquehanna River more often. The team found that reducing pollution loads upstream of the dam would pose a more effective solution that dredging, bypassing or other operational changes, which would come with high costs and low or short-lived benefits.
The USGS report, Sediment Transport and Capacity Change in Three Reservoirs, Lower Susquehanna River Basin, Pennsylvania and Maryland 1900–2012, is available online.
The tale of Harriet Tubman and the Underground Railroad is revered as one of the most influential moments in the emancipation of slaves in the United States. As the birthplace of Tubman, the Eastern Shore of Maryland holds a rich history in its expansive farm fields, quaint settlements and wetlands that nestle into the crooks and creeks of the Chesapeake Bay. Many individuals, municipalities and organizations have learned the stories of those that traversed the trail, risking their lives for freedom, and have collaborated to permanently preserve important landmarks along the Underground Railroad.
The Harriet Tubman Underground Railroad Byway spans 125 miles through Caroline and Dorchester Counties in Maryland. Along it, visitors can explore the secret network of trails and buildings of the Underground Railroad, a path forged by freedom-seeking slaves and abolitionists in the 19th century. It does not take long for those on the trail to learn the trials, tribulations and successes that occurred along the way - all because a few people decided to band together to overcome adversity and do extraordinary things.
To view more photos, visit the Chesapeake Bay Program’s Flickr page.
Images by Will Parson
Captions by Jenna Valente
The Chesapeake Bay region could receive nearly $38 million in conservation funding under President Obama’s proposed budget for the 2016 fiscal year, announced earlier this month. If approved by Congress, the funds could conserve more than 7,500 acres of land throughout the Bay watershed.
Of the proposed $37.8 million, $33.3 million is tied to the Rivers of the Chesapeake Collaborative Land and Water Conservation Fund (LWCF) proposal, which focuses on protecting the James, Nanticoke, Potomac, Rappahannock and Susquehanna Rivers and the lands that surround them. By improving water quality, providing critical habitats for fish, shellfish and migratory birds, and offering opportunities for public access, preserving these landscapes would help meet the goals of the Chesapeake Bay Watershed Agreement, which guides the restoration of the Bay, its rivers and streams and nearby lands. Bay Program partners are currently collaborating on the creation of a land preservation strategy for the region.
“These are the places we love. The places we boat, hunt, fish, and hike, the places we take our children to explore the outdoors, and the places people come to visit,” said Joel Dunn, Executive Director of the Chesapeake Conservancy, one of the partners behind the Rivers of the Chesapeake proposal. “Protecting these places supports our communities and economy and is also important to maintaining the ecological health of the Chesapeake Bay and its watershed.”
The President’s $4 trillion budget recommendation includes $900 million for the national Land and Water Conservation Fund, which supports the conservation of land and water resources across the United States and aims to provide outdoor recreation opportunities to all Americans.
Learn more about how the President’s proposed budget would support conservation projects in the Bay region.
When too much nitrogen enters the Chesapeake Bay, it can fuel the growth of harmful algae blooms that block sunlight from reaching underwater grasses and create low-oxygen areas, or “dead zones,” that suffocate marine life. But some key successes in curbing the amount of nitrogen entering local waterways have a potentially surprising source—the Clean Air Act.
In a factsheet released last week, the U.S. Environmental Protection Agency (EPA) outlines how declines in air pollution have substantially reduced the amount of airborne nitrogen that ends up in the Bay, helping the agency and its partners stay on track to meet the water quality goals of the Total Maximum Daily Load (TMDL), or “pollution diet,” which representatives from across the Bay region recommitted to achieving as part of the Chesapeake Bay Watershed Agreement.
Polluted air can have quite an impact on the health of local waters: scientists estimate that one third of the nitrogen in the Bay comes from the air through a process known as atmospheric deposition. When our cars, power plants or other sources emit air pollution, it can be carried by wind and weather over long distances until it falls onto land or into the water.
“Atmospheric deposition falls everywhere on the Chesapeake watershed, from forests, to fields, to parking lots,” said Lewis Linker, modeling coordinator with the Chesapeake Bay Program. “When this load of nitrogen is reduced, it improves water quality everywhere from stormwater runoff, to small headwater streams, …to the Chesapeake Bay.”
Even pollution emitted thousands of miles away can eventually end up in our waterways. While the area of land that drains into the Bay spans six states and 64,000 square miles, the Bay’s “airshed”—the area of land over which airborne pollutants travel to enter the estuary—is nine times that size. Nearly three-quarters of the airborne nitrogen that eventually ends up in the Bay is generated by sources within this airshed, and the remaining 25 percent is emitted from sources even farther away. Which is why, says Linker, national policies like the Clean Air Act are essential in reducing the amount of pollution that reaches the Bay.
“To restore the Chesapeake, the citizens of the Chesapeake watershed have done a lot of bootstrapped cleanup in their own backyards and watersheds,” said Linker. “But when it comes to atmospheric deposition of nitrogen, the reduction can’t be done by the Chesapeake state partners alone—it’s a job for the whole nation.”
For more on what you can do to curb air pollution, Take Action.
Learn more about the EPA’s efforts to curb nitrogen deposition in the Chesapeake.