Would you swim in the Christina River? It may soon be possible
For hundreds of years, the Christina River has wound through northern Delaware and what is now Wilmington, serving as a thoroughfare for settlement, trade and industry.
The Christina was the site of Delaware’s roles in the American Revolution, the Underground Railroad and the world wars before lapsing into contaminated decay.
Now, with the sources of pollutants more under control and the state testing a promising method for neutralizing toxins in the water, scientists and environmentalists say a new future for the Christina River is on the horizon. It’s a future in which the river and its tributary, the Brandywine, sustain habitats for wildlife, and Wilmington residents are able to fish, swim in, and even drink from both waterways.
Scientists and conservationists warn it will still take plenty of time to get Wilmington’s portion of the Christina from its current state — with the state warning the public not to eat fish from it more than once a year — to one that can be widely and safely used for recreation. And they don’t want to promise exactly when it can happen.
But sometime in the next 10 to 20 years? Most agree that fishing and swimming in Wilmington’s waters won’t be out of the question.
“The water quality is improving; there’s a lot of people down here,” said Jen Adkins, a board member at the Christina Conservancy, a group focusing on preservation of the entire Christina watershed. “For the first time, we’re really starting to think of the river as a living resource … which is not how people have thought about it for a long time.”
The Christina Conservancy is heading up a group of planners, developers and scientists – including the state’s environmental department – all working on improvement projects on or near the two waterways.
The conservancy received a grant from the U.S. Fish and Wildlife Foundation last month to plan how to get the lower Christina and Brandywine – the parts that run through Wilmington – to that fishable, swimmable future. The group will coordinate projects to focus on – and seek funding for – advancing that goal.
There’s no shortage of activity, both proposed and underway.
The Riverfront Development Corp., having exhausted most of the empty land on the Wilmington Riverfront, is setting its sights on re-creating the waterfront residential and entertainment district on the opposite banks of the Christina. There, the city’s South Wilmington Wetlands Park, intended to restore fish habitats and alleviate flooding in the Southbridge neighborhood, is being constructed.
Along the Brandywine, upstream of Market Street, a historical dam was removed as part of an effort to reintroduce American shad to their ancestral spawning waters. Downstream from Market Street and north of the Brandywine, the city commissioned a planning study that envisions the cleanup of brownfields (land that may be contaminated) in an economically depressed corner of northeast Wilmington, as well as new apartments and riverfront parklands.
“We’re at the point where we can see the light at the end of the tunnel,” Adkins said. “Now what do we need to do to get there?”
It could mean combining a cleanup effort with a habitat restoration one or prompting developers to contribute to waterfront access.
Gerald Kauffman, director of the University of Delaware’s Water Resources Agency, has studied decades of water quality measurements in the Christina River. Between 1995 and 2015, he saw improvements in dissolved oxygen and bacteria levels.
He credits the commercial development and cleanup of the Wilmington Riverfront over the past two decades with reducing and preventing toxic runoff from entering the Christina.
“There’s nowhere better to see where the economy and the environment can rise hand in hand than here,” Kauffman said.
Legacy contaminants – particularly chemicals like polychlorinated biphenyls, or PCBs –are among the main barriers to a clean river.
Using a technique they first piloted in Dover’s polluted Mirror Lake about five years ago, hydrologists at the Department of Natural Resources and Environmental Control are testing a method to contain the toxins in the water.
In Dover, state scientists dumped activated carbon pellets called SediMite, similar to the material in a tap water filter, into the water to bind to and detoxify the pollutants. In a year, they took water, sediment and fish samples and found a 60% reduction in pollutants.
After five years, PCB concentration in the lake’s resident fish had been reduced by 80%.
BACKGROUND: $1 million project reduces Mirror Lake pollution
“Normally models showed it would have taken anywhere from 20 to 50 years for PCB concentrations to be reduced to the same level if we just shut off all the sources,” said John Cargill, a co-manager of DNREC’s Watershed Approach to Toxics Assessment and Restoration program. “We accelerated that by tenfold.”
This year, Cargill and co-manager Todd Keyser have done the same in a ditch off A Street that will drain the new South Wilmington wetland park into the river.
This time, they added a layer of microorganisms on the carbon pellets to break down the PCBs.
Six months in, samples show the concentration of PCBs in surface sediments are down by about 25%, Cargill said.
If the results of more monitoring are similarly positive, Keyser said, that could mean DNREC will replicate the technique in other sites along the river to get it to its fishable, swimmable future.
On the land side, they’ve also spent the past decade targeting industrial sources of pollutants and said they’re seeing the results in fish tissue samples.
“We couldn't even be looking at doing a plan like this if all of it hadn't come before,” Adkins said.
Jeanne Kuang covers Wilmington for The News Journal. Contact her at email@example.com or (302) 324-2476. Follow her on Twitter at @JeanneKuang.