A team of scientists has found that reducing pollution in the Susquehanna River watershed—which includes portions of New York, Pennsylvania and Maryland—could ease the environmental effects of an “essentially full” reservoir behind the Conowingo Dam, whose pollution-trapping capacity has diminished in recent years.
The reservoir behind the Conowingo Dam—as well as those behind the Holtwood and Safe Harbor dams—has for decades trapped particles of sediment flowing down the Susquehanna River, as well as the nutrients that are often attached. But according to research from the Lower Susquehanna River Watershed Assessment (LSRWA) team, this reservoir is full. 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.
While researchers explored strategies for managing sediment at the dam, the team found that reducing pollution loads upstream of the dam would pose a more effective solution to the “full reservoir” problem. Indeed, dredging, bypassing or other operational changes would come with high costs and low or short-lived benefits. But adhering to the Chesapeake Bay’s “pollution diet”—and taking additional steps to reduce pollution where possible—would offer management flexibility and environmental benefits.
The Chesapeake Bay Total Maximum Daily Load (TMDL) was established in 2010 to reduce nutrient and sediment loads across the watershed. Lowering these pollutants is integral to restoring the health of the Bay: excess sediment can cloud the water and harm underwater grasses, fish and shellfish, and nutrients can fuel the growth of harmful algae blooms. While the LSRWA team did find that the effects of the sediment that “scour” from the Conowingo reservoir cease once it settles to the bottom of the river, the effects of nutrient pollution linger. Green infrastructure, forest buffers and sound farm and lawn management can help businesses, landowners and individuals contribute to a restored Chesapeake.
Researchers from the National Centers for Coastal Ocean Science (NCCOS) surveyed three rivers in the Chesapeake Bay region to examine how variations in land use and development impact the health of the Bay, finding that water quality and aquatic animal health could help gauge the overall well-being of coastal regions.
The NCCOS assessment, conducted from 2007 to 2009, explored linkages between land use, water quality, and aquatic animal health along the Corsica, Magothy, and Rhode Rivers. Researchers measured water quality for dissolved oxygen, nutrient concentrations and water clarity, and based aquatic animal health on the growth, disease rates and diversity of fish and shellfish stocks.
As the population of the Chesapeake Bay region grows from 17 million to a predicted 20 million residents by 2030, an increasing number of people will rely on the Bay for their food, recreation and livelihoods. The assessment results suggest that environmental pressure from development could both weaken the capacity of the Bay to provide these services and counteract the benefits of current restoration efforts.
“Luckily, ecosystems tend to be resilient; many are able to maintain a state of relatively strong health when faced with environmental stress,” the report states. However, it also clarifies that if the health of coastal waters is pushed beyond a point of recovery, it could affect the ability of the Bay to cope with “environmental stress”—including increased rainfall related to climate change.
“The science challenge, going forward, is in identifying and communicating where systems fall relative to some threshold or tipping point,” the report states. Results of the assessment can be used to inform “smart development plans” that can balance the effects of human activities with better support of Chesapeake Bay’s resiliency.
Rapid population growth and development remain the top threats to the health of the Potomac River Watershed, according to the Potomac Conservancy’s eighth annual State of the Nation’s River report. But the advocacy group hopes implementing smart growth strategies will help the waterway withstand pressure from a growing community.
Despite being listed as the nation’s most endangered river by American Rivers in 2012, the Potomac River’s overall health has improved in recent years. In 2013, the Potomac Conservancy raised the waterway’s grade to a “C” after giving it a “D” grade in 2011. Now, with an estimated 2.3 million new residents expected to move into the communities along its shores by 2040, the Conservancy fears a rapidly changing landscape could undo years of progress toward restoring the Potomac.
“Population growth is likely to bring positive changes to our region including more jobs, higher home values, and a more robust local tax base,” the report states. “But, left unplanned, that growth could also spell disaster for the health of our lands, waterways, and drinking water sources.”
With the region facing forest loss, polluted rivers and streams and an aging water infrastructure, the report offers a range of “smart planning opportunities” as strategies to meet the needs of a growing population without further harming local waters. The Conservancy hopes approaches including forest buffers, mixed-use communities and rain gardens, along with a focus on redevelopment in existing areas rather than new development on untouched lands, will allow for the continued improvement of the Potomac River’s health.
For the uninitiated, paddling the Anacostia River in Washington, D.C., provides an opportunity to discover a hidden natural gem. Paddling away from the riverbank on an early fall evening, we quickly begin to slide past egrets hunting in the shallows and turtles diving deep to avoid our canoe. Joining them is a kingfisher, chattering as it circles before landing on a branch, and a bald eagle, following the course of the river upstream and disappearing around a bend. Moments like this are why the Anacostia Watershed Society (AWS) hosts free paddle nights like the one at Kenilworth Park in D.C. — to change perceptions of a river with a reputation of being heavily polluted.
“From the perspective of someone who’s heard about the river but never been there, I think the most surprising thing is that there’s a whole lot of nature,” says Lee Cain, Director of Recreation at AWS. “When you get out there, there’s some places where you’re there and you think, ‘Am I in the middle of West Virginia?’”
Cain says he heard many negative stories about the Anacostia River before visiting it for the first time, but his perceptions changed after experiencing it up close. The Anacostia is indeed still plagued by trash, sewage, toxins and runoff. But it is also a place where Cain has seen fox and deer swimming across the river, where egrets aggregate by the dozens at nighttime, and where bald eagles and osprey lay their eggs in March so their fledglings can feed on shad. In June, the 9-mile Anacostia Water Trail officially opened, featuring many natural areas and recreation sites along the river.
“You’re probably going to see a higher density of wildlife on this river than you might in even the Jug Bay wetlands,” says Cain.
Cain says the Anacostia is better than it was 25 years ago, when cars, refrigerators and tires were the big items being pulled from the river. Positive signs of change have come in the form of a plastic bag fee passed by the D.C. Council in 2009, and a ban on plastic-foam food containers that passed in June. A group called Groundwork Anacostia River DC has implemented litter traps in several tributaries, and AWS operates a trash trap study as well. The Anacostia Revitalization Fund, established in 2012, has provided funding for local initiatives aimed at restoring the river’s health. DC Water’s $2.6 billion Clean River Project will remove 98 percent of combined sewer overflows to the Anacostia by 2022, keeping 1.5 billion gallons of diluted sewage from entering the Anacostia every year. And the Pepco Benning Road Power Plant, which ran on coal then oil for over a century, sits quietly near the Anacostia, shuttered since 2012 and slated for demolition.
“If [the power plant] has some source of PCB contamination then at least that source is gone and now, when we clean out the soil, we’ll have a pretty clean space,” says Cain.
He says it has been a big year for toxins in the river, with the District of Columbia taking core samples along the river to assess what is down there and what it will cost for removal.
“One thing that’s encouraging is that it took us a couple centuries to sort of destroy this river, and then it’s only taken us about 25 years to get it to where it is now,” says Cain. “So you can imagine in another 25 years where it will be.”
In the meantime, AWS will continue working toward the goal of a fishable and swimmable Anacostia by 2025. Getting people on the Anacostia on paddle nights is just one effort to let people see firsthand what it already has to offer. The hope is that some of those visitors might become volunteers with AWS’ or their partners’ trash, stewardship, education and other programs.
“There’s a lot of the Anacostia that’s not exactly accessible to people, and in order to have all of these things and these efforts continue we need the support of the public,” says Cain. “We need people to recognize that this is a resource worth saving.”
To view more photos, visit the Chesapeake Bay Program Flickr page.