GARDEN CITY, Idaho — Arborist Zeke Willard secured a large downed tree to the Boise River’s south bank Jan. 27, a project that organizers said reduces erosion risk, improves trout habitat and potentially provides a template for future work.

The fallen tree now “has some value, other than watching it burn,” said Mark Zirschky, who manages Boise River Flood Control District No. 10.

A wider variety of projects can be completed during the winter maintenance season under the district’s stream alteration permit, recently reworked with help from the Idaho Department of Water Resources and the U.S. Army Corps of Engineers, he said.

Hazard trees had to be removed from the river or burned under previous permit requirements. Under the revision, trees that have fallen into the river can be anchored to the bank for various purposes.

Trees and woody material thus become an additional tool for the district, which works to keep the river running safely and beneficially in cooperation with landowners, irrigation districts, agencies and nonprofits.

Protecting river-adjacent public and private property is another potential use of the downed trees and other woody material, Zirschky said.

Added benefits to the project — next to a river-adjacent pedestrian and bike path that abuts Garden City backyards —include stabilizing the riverbank and encouraging vegetation to fill in, thus reducing risk to the path and other property, he said.

High winds last summer blew the mature cottonwood into the river. Zirschky noticed how the tree and its branches deflected flows away from the bank, similar to an engineered “bank barb” of riprap rock and wood, according to a news release.

He consulted with Boise Valley Fly Fishers conservation director Troy Pearse and Idaho Fish and Game southwest regional fisheries manager Art Butts.

Boise Valley Fly Fishers paid for the project. Wood provides trout fry with winter cover from predators and can improve and diversify habitat, club president Brian Martin told Capital Press.

Fall-spawning brown trout can be found in the river stretch where the project was completed.

Willard, a club member, used a hollow-braid polyester to secure the tree. The material is strong and allows for some movement, he said. Considerations included tree and root plate orientation, anchor points and bank features.

The project is a continuation of the club’s work with Flood 10 to enhance the river, BVFF’s Pearse said in the release. “We were glad to see the permitting agencies were excited about repurposing woody materials to protect the stream bank and enhance fish habitat.”

Club members also have been marking brown trout redds from Boise to Star to help winter maintenance crews avoid damaging them.

Wood traditionally is removed from the river quickly to reduce risk to infrastructure and novice floaters. Fish and Game and Flood 10 for years have sought opportunities to keep wood in the channel where appropriate.

“We are excited that these efforts are continuing and that more agencies, municipalities and citizens are recognizing the importance of wood in the Boise River,” Butts said in the release.