Every year, as a part of river channel maintenance, the Boise Flood District removes dozens of trees that have fallen into the river. This is necessary because the Boise River runs through an urban area and must be managed to stay inside its current banks so it doesn’t wander off course and destroy houses or city infrastructure. For example, here is a picture of damage done where the river carved out the bank and greenbelt, near some houses by Lake Harbor a few years ago. Removing trees helps reduce flood risk because it is easy for them to wash up against a structure like a bridge piling and divert water out of bank at high flows, which could cause a flood event. You can find out more details about the Boise Flood District’s operations at their website www.boiseriver.org

An unfortunate side effect of removing fallen trees is it takes away cover for fish—especially young fish who need that cover to hide from predators like diving mergansers, blue herons and larger fish.  Over the last 10 years I’ve been fortunate to have discussions with several fish biologists from Idaho Fish and Game and one thing they all have reiterated to me is they believe the lack of woody cover on the Boise River is limiting the number of trout fry that make it into adulthood.

Over the years, the Boise Flood District has been evolving their operations to be more fish and tree friendly, as described in this News Story.  BVFF has been working with the flood district for the last 5 years. And while some may see them as a destructive force, they have shown us that they are river stewards who care about the Boise River. They have helped us with 2 gravel augmentations and have partnered with us to develop a program to avoid brown trout spawning areas as they use large excavators in the river for their annual winter maintenance work.

Last year BVFF partnered with the Boise Flood District and Idaho Tree Preservation Co to pilot a new program on the Boise River to try retaining a tree that had fallen into the Boise River, instead of removing it. Over the last year we monitored the tree it to make sure it stayed in place during spring and summer flows and were pleased to see that it held well and there are signs that the riverbank erosion is starting to recover. Here is an article with more details about that project.

This fall Jeff Jones and I floated the Boise river to review new trees that had fallen into the river which might be a good candidate for being retained by the flood district. We wanted trees that were: 1) Still semi-attached—which will help them stay in place; 2) In an area that is adjacent to good trout spawning habitat; 3) Fallen at a downstream angle, and help deflect flows from the bank; and 4) Are located in a wide section of river and are not a hazard for floaters. We were able to identify three additional fallen trees in the same general zone as the first tree, just above and below Glenwood bridge. Having the trees in a central zone makes retaining and monitoring the trees much easier.

Today (Jan 14, 2026), Boise Flood District 10 worked with Idaho Tree Preservation to retain the 3 trees. BVFF is extremely grateful to Boise Flood District’s willingness to try new approaches like this to manage the river. We are also thankful to have Idaho Tree Preservation’s support on this project. Having a master arborist involved has been the key to making it work.  Retaining the trees is expensive, but Zeke and Idaho Tree Preservation have been generous and donated a good amount of the work to the club.  Our thanks to Boise Flood District, Idaho Tree Preservation and Idaho Fish and Game for their ongoing partnership on this project.

We are working on some signs to place at the Willow Lane and Glenwood floater access points, to help them understand that this section of the river is designated as a “float at your own risk” section and is not maintained the same as the upper floater zone—which is stripped of all woody cover to make the river safer for the multitude of summer floaters. We have permission from King County Washington to leverage this sign and hope to install them in the next couple of years.