With the system of dams and diversions in the Boise River there is a lack of spawning gravel recruitment into the lower Boise River, and this situation has some negative implications for the fishery. Trout Unlimited took the lead to implement projects more than fifteen years ago. But first let’s look at a recent project.
First, our Heron Park spawning gravel project in 2019-2020 was the brain child of a couple chapter members who were aware of bank revegetation work in Garden City. With a coffer dam planned to dewater the bank for the construction, a permit to fill large geotextile bags with clean spawning gravel was approved by the US Army Corps of Engineers and Idaho Department of Water Resources.
Typically a cofferdam will use road mix or other fill material and the bags will be lifted into place and then lifted out when the work is done. In this case the bags were cut and the fabric removed and the gravel left in the Boise River.
In early 2020 as the pandemic was setting in there was an opportunity to walk along the river bank and the first hint of spawning success was commotion at the stream edge when some rather large trout bolted for deeper water. The second indicator was a redd in the spawning gravel.
Second, we go back in time to our Heron Creek Project in east Boise (not to be confused with Heron Park in Garden City several miles west), and a tumblr entry in 2011 showing a redd where spawning gravels were placed in September 2009.
And here’s a video of the spawning gravel placement in 2009 where we used a bucket brigade of volunteers:
Back in 2005 we placed spawning gravel in two side channels of the Boise River. One at Warm Springs Golf Course behind the number 10 green. The other is on the south side of the river across from the golf course at the Island Side Channel. Here are some photos: