A stream restoration project is removing several hundred feel of concrete carrying the Jones Falls to Robert E. Lee Park, adding habitat for brown trout and reducing polluting runoff.
In a forested section of the Jones Falls just north of the city line, moss covers a steep incline beside the stream, leading up to a bluff.
A closer look reveals that the bank is not natural. It's concrete, put there more than 30 years ago as part of an effort to prevent flooding.
While it might blend into the scenery today, environmentalists say the 800-foot-long concrete stretch is a major disruption for brown trout that thrive in upstream portions of the Jones Falls watershed, in Baltimore County's Greenspring Valley.
But the stream is on track to regain a more natural profile by the end of summer. Advocates say a $600,000 project to remove the concrete will eliminate a barrier that is often impassable for trout and prevent pollutants and sediment from passing downstream.
"There are really significant ecological benefits," said Carl Simon, director of programs for Blue Water Baltimore, an environmental group that supports the project.
The Jones Fall restoration could be a prototype for similar efforts to remove paved gullies and stream beds across the region, restoring natural filtration of stormwater runoff and habitat for aquatic creatures.
"We're hoping to learn a lot about how stream restoration works," Simon said.
For decades, the section of the stream has made a single eastward curve toward Robert E. Lee Park and Lake Roland after passing below a Jones Falls Expressway overpass. The unnaturally wide and flatconcrete stream bed carries water through an area that was once home to Rockland Bleach and Dye. Repeated flooding prompted the manufacturer to move to East Baltimore in the early 1980s.
The wide basin often keeps the stream no more than a few inches deep. Engineers plan to slow the flow, deepen the bed and add natural obstacles. They will build a winding path for the water, carrying it over rocks and logs to create deeper pools. They are redirecting the stream across what is now a grassy area close to Falls Road, using heaps of sandbags to divert the water as the work progresses.
Trout enthusiast Jim Gracie and his company, Brightwater Inc., designed the project. Crews from Millersville-based engineering contractor Environmental Quality Resources are scheduled to begin work soon.
The changes could be significant for brown trout and the enthusiasts who fish for them, said Gracie, a longtime volunteer with the Maryland chapter of Trout Unlimited, a fisheries conservation advocacy group.
Anglers consider the species to be the smartest and most challenging to catch of any trout variety in the state.
The Jones Falls contains one of Maryland's most robust populations of brown trout, Gracie said. Its watershed stretches across Northwest Baltimore and into central Baltimore County, in the area between Interstates 795 and 83.
But the fish are too large to reliably pass through the concrete section, and the pavement also means the water can get too warm for their liking. Environmentalists consider thriving brown trout populations to be an indicator of good water quality.
Brown trout are not a native species, originally coming from Europe, and can outcompete native brook trout because they are larger and more resistant to disease. They are a close relative to Atlantic salmon and can grow about a foot long. They are found in about 80 streams across Maryland.
But numbers of brook trout have declined over the years as the paved surfaces that come with urban sprawl have warmed waters too much for them. Brook trout have not been seen in the Jones Falls since the 1990s, said Mark Staley, central region fisheries manager for the Maryland Department of Natural Resources.
Even though the brown trout are transplants, conservationists want to see them succeed because self-sustaining populations of wild trout have declined drastically since the 18th and 19th centuries.
The Jones Falls watershed is still a hotbed for brown trout because marble and limestone found naturally in its bed keep its waters cool enough for the hardier species. The continued presence of thousands of brown trout is a promising indicator in a watershed that, downstream, is a significant source of pollution for Baltimore's harbor.
"It's very rare to have a strong trout population that close to an urbanized area and to have wild trout inside of the Baltimore Beltway," Staley said. "Trout and lots of urbanization usually are mutually exclusive."
Though it is a relatively short segment and is upstream of the Lake Roland dam, the removal of the concrete and the stream restoration will help improve water quality downstream, Simon said. Blue Water Baltimore estimates a reduction of more than 100 pounds of nitrogen runoff and 30,000 pounds of sediment each year.
State natural resources officials who approved a grant for the project said it is a cost-effective way to reduce the amount of pollution entering waterways through runoff. The money is coming from the state's Chesapeake and Atlantic Coastal Bays Trust Fund, an account established in 2008 using revenue from Maryland's gasoline tax and rental car tax.
Organizers hope the project will one day provide another public access point to the Jones Falls, on the west side of Falls Road between the I-83 overpass and Robert E. Lee Park.
Currently, there are just a few places that trout fisherman can easily access the stream because much of it runs through private estates in the Greenspring Valley, Gracie said.
"There's virtually no public access," he said. "We're hoping this can become a public access area where people can fish."