MISSOULA — The city's slow acquisition of land along the Clark Fork River and the West Broadway corridor over the past few decades may now offer opportunities to enhance river restoration and recreation and address area habitat.
The city on Wednesday unveiled three design concepts for a significant river project proposed between the Bitterroot Branch trestle and the California Street Bridge.
The area includes Silver Park and the Broadway Island, along with the old Flynn-Lowney irrigation ditch.
Morgan Valliant, associate director of ecosystem services for the city, said the project was born from an “issues and opportunities map” developed over the past several decades. As the city acquired land in the area, a vision began to emerge.
“The city owns land on either side of this project area, owns an island in the middle of the river, and owns the irrigation ditch and its water rights,” said Valliant. “The acquisition of that ditch was not for irrigation water. It was to put more water back into the Clark Fork River and reduce the cost of road construction out in the Sxwtpqyen area.”
The future of the old irrigation ditch lies at the heart of all three proposals, though other issues are in play. Trails in the area have few connections and the boat ramp at Silver Park no longer functions as intended.
River erosion also threatens public infrastructure, including trails and portions of the civic stadium. Fish passage is also difficult, Valliant said.
“We have major issues with fish passage and debris. The ditch company had dumped almost five feet of fill into the river to divert water to the irrigation ditch,” said Valliant. “We're talking about reconstructing trail connections, reconstructing the river itself, and dealing with all the irrigation infrastructure that's in there.”
Design Concepts
All three design concepts would address major issues including erosion, trail connections and fixing the boat ramp. But from there, each plan offers its own opportunities.
The first concept would add riffles to the Clark Fork River to aid in the passage of fish and allow seasonal high water to flow into the old irrigation channel. It maintains the two bridges connecting the north bank to Broadway Island and expands a series of trails both north and south of the river.
“A lot of the things you see in concept one were carried through to concepts two and three,” Valliant said. “This is the bare minimum of what we need to do in this project area to meet the goals that our community has for this reach of river and the trails on both banks.”
The second concept would create a series of rapids in the river and bring the trail north of the river closer to the water.
To do so, the proposal would re-contour the irrigation ditch, add wetlands to Broadway Island, and carve two seasonal high-flow channels across the island, connecting the ditch to the river.
“Side channels of the Clark Fork are important,” Valliant said. “Any time we can create side channels within our river, it allows us to meet a number of goals. It would be a perennial side channel of the Clark Fork and carry water throughout the entire season.”
The third concept also includes rapids and enhances trail connections. However, it removes the two bridges that serve Broadway Island, reserving it primarily as urban habitat. The proposal also deepens the irrigation ditch and creates a new surfing wave.
Valliant described it as a “roller wave” that would enhance recreation. Unlike Brennan's Wave, it would function year-round.
“We know what kind of flows need to come down the side channel,” he said. “This would be a wave that functions in the heat of the summer. Brennan's Wave is very seasonal in nature. This wave would function in July and August.”
While the city plans to present a final plan next spring, Valliant said it's likely that it will include elements of all three proposals. Cost estimates haven't been provided, but funding sources would possibly include the Missoula Redevelopment Agency, grants and fundraising.
Project backers also believe that all three proposals could be permitted, but that process will play out once a final plan is adopted.
Rob Roberts with Trout Unlimited said a range of environmental issues would also need to be addressed including the Endangered Species Act, river modeling with FEMA, permitting from the Army Corps of Engineers, and compliance with the state's Streambed Preservation Act.
“There's a lot of analysis and permitting that would go into a project of this scale,” Roberts said. “That's definitely not lost on us at all. But we have vetted this at a very course scale. We believe everything we're talking about is permittable in the long run.”
Valliant added that whatever concept emerges, it will take time to implement.
“Regardless of where we land for the master plan, I envision a phased approach to some of this work,” he said. “This could be a project that gets implemented over several different phases as funding becomes available.”
