A collaborative effort on the Allegheny National Forest has opened up several streams to brook trout for the first time in over 100 years.
A project of the U.S. Forest Service, the Western Pennsylvania Conservancy, the National Forest Foundation, and National Fuel Gas resulted in replacing 10 stream crossings on eight tributaries that pour into a five-mile stretch of the East Branch Tionesta Creek.
Those streams add up to eight-and-a-half miles of new waterway for fish.
“For 100 years the branches have been cut off both sides (of the East Branch),” Nathan Welker, a Forest Service fisheries biologist and member of the ecosystems management team, said. “We’ve basically put the limbs back on the tree.”
The project cost about $200,000, with most of the funding provided by NFF. National Fuel replaced two of the culverts on its own at an estimated expense of $50,000.
The conservancy acted as the general contractor on the remaining eight projects.
The environmental non-profit agency pulled in additional grant funding, secured the necessary permits, and generally oversaw the work, Watershed Scientist Josh Burkett said.
“The conservancy played a very big role in this,” Welker said.
Applied Geology and Environmental Services (AGES) was hired to perform the work.
“We do a lot of stream- and wetland-related work,” Bruce Dickson, AGES chief scientist, said. “The Forest Service had done all the design. The conservancy had done all the permitting. We did the installation.”
Building a road over a stream requires allowing the water to pass under the new road.
On the ANF, and in many other places, that process has historically involved installing a pipe that will handle the estimated flow of the stream in a 25-year-flood event.
That’s a good start and Pennsylvania Department of Environmental Protection regulations still require that.
But new language in the regulations calls for more, as does best practice.
“We’d like to get the word out that looking at the flow is not sufficient anymore,” Welker said.
The 25-year event language is still on the books, but there is a new section that requires allowing passage to aquatic organisms. “The main goal is to provide that natural channel through the crossing,” Welker said.
Several species of fish – brook trout and some species of darter in particular – as well as amphibians and reptiles must be able to move up a stream past roads.
Singling out brook trout, the state fish, is more about generating funding than showing an organizational preference for the species. “If we can benefit brook trout, that’s one way of finding funders,” said Dickson, who is a member of Trout Unlimited,.
The new culverts are much bigger than the old culverts. The largest used in the 10 crossings in the project was 11 feet 8 inches in diameter.
“When we make these recommendations for a pipe that’s five times as wide, that’s shocking to them,” Welker said.
The new pipes eliminate a number of barriers to fish movement created by the old practices.
At high flow, a stream squeezed through a pipe can create a “scour hole” at the output, Welker said. “You end up with a jump barrier.”
Some culverts drop water three feet to the pools at their outlets – an impossible leap for even adult brook trout, he said. Much smaller drops are sufficient to prevent younger fish and smaller species from moving upstream.
A culvert designed only to manage the flow of the stream also creates a “velocity barrier” for fish, Welker said. The flow is too strong from the fish to navigate.
“A crossing can be a barrier for any number of reasons,” he said.
The new culverts were “designed for bank-full width,” Welker said.
Most of the new passages are “squashed pipe” culverts. The cylindrical, corrugated metal pipes are “squashed” so that they are slightly wider than they are tall and they are flattened on the bottom.
About one-third of the pipe is buried below the existing stream bed and material from or matching the stream bed is added to the culverts. Over time, more material is washed into the culvert, some remaining in place, some moving through. “The material inside the culvert provides substrate and habitat for the aquatic organisms,” Dickson said. It also reduces the speed of the water through the pipe.
The larger pipes do come with a higher price tag. But that cost is offset over time, Welker said.
One whole crossing might cost about $5,000 the old way, Welker estimated.
The 11-foot pipe used in one of the replacements cost $6,800, Dickson said.
There is an offset for that initial expenditure. “With these, it’s set it and forget it,” Welker said.
Many culverts created under the old guidelines required annual maintenance and had to be replaced every six to eight years, Dickson said.
He expects the new culverts to withstand much larger water flows and allow debris to flow through rather than jamming at the culvert entrance and impeding water.
“These culverts are going to withstand a 500-year flood event,” Forest Service Hydrologist Chuck Keeports said.
And, “the replacement times are much longer,” Dickson said.
“You won’t have to touch these culverts for 50 years,” Welker said.
For companies that cannot afford the up-front costs, “there are inexpensive alternatives to throwing in an undersized pipe and repairing it every year,” Welker said. One option is building a bridge – something that can be done for about $5,000 given the proper equipment and expertise.
There are many opportunities for more projects and the representatives of each group expressed a willingness to work together in the future.
Welker said there are at least 2,000 stream crossings on the ANF.
The organizations are willing to help people who have to build roads that fit the new regulations.
“Anybody on or near the ANF who would like a little help is welcome to call the Forest Service,” Welker said. “I’m sure the conservancy and AGES would be happy to help.”
“Most people want to do it the right way,” he said.