Trout Unlimited - Ted Trueblood Chapter, Idaho

The Island Creek Project will restore habitat for salmonid spawning and rearing tributary to the Boise River for the purposes of restoring designated beneficial uses that are not fully supported in the Boise River. The channel will be about 3,300 feet (slightly over 1/2 mile) in length.

The purpose and goal is to restore a 1/2 mile side channel to the Boise River to provide optimal spawning, rearing, and winter holding habitat for aquatic species, with the capability to increase the restoration activities to 2 miles along the Boise River.

Based on the limiting factors and potential of Island Creek, the following design goals are proposed:

The result is a sinuous stream with a low width-depth ratio, quality pools, capable of moving fine sediments through potential spawning areas.

(Project pre-construction photos, June 2002)

a. View from bridge on Linder Road of upstream end of project. A deceptive view because the weeds have not yet covered the stream as will later in the summer through late winter.	b. View looking further downstream. Only the deepest areas of the channel are not encroached with aquatic weeds (parrots feather principally). This photo was taken June 18, 2002 prior to the channel being totally choked by weeds.
c. Looking generally upstream. The banks and riparian area show strong grasses. Aquatic weed patch is encroaching on the left bank.	d. With few exceptions the stream depth was near uniform at shin deep to knee deep.

Near-term Resource Objectives:

Design the stream to provide optimal spawning and rearing habitat. Construct the stream using contributed equipment and operational costs where possible.
Provide in stream cover using a variety of techniques such as boulder placement, undercut banks, large organic debris (secured), and planted vegetation.
Achieve 15-30 percent of channel suitable spawning gravels; the remaining 70 percent will be juvenile rearing space.
Monitor the construction, recovery, and productivity of the stream using photography, transects, fish observation and shocking.

Long-term Resource Objectives:

Monitor fish populations of the Boise River adjacent to the side channel and aim to achieve increased population densities for naturally produced salmonids than currently found (Mullins 1999, IDFG 1998).
Use the experience and partnerships from the initial project to spur further restoration work along the lower Boise River.

(Project pre-construction photos, June 2002)

e. Here's an area along the stream where the weed patch extended several yards across the stream bottom. Clear no fishery value when the stream is shallow and choked like this!	f. A stab with a shovel in the stream bottom causes a plume of fine sediments and silts that cover the bottom. Only in a few places could we find a cobble bottom. And, no surprise, no aquatic invertebrates under the rocks.
g. TU brain trust (officers and board members), landowner and consultant discuss the options.	h. A desired condition for this stream at its downstream end just before entering the south channel Boise River. Note the narrow channel width (just right of center in photo) and strong grass community along the stream banks. Aquatic weeds are absent from this reach.

Construction Technique:

The stream would be constructed in several phases from upstream to downstream over a period of 2-3 years prior to spring runoff if possible;
Sedimentation ponds would be initially constructed to help remove sediment from the construction operation;
Straw bales and silt fences would be used to filter the water from each pond. The general proposed meander pattern would be staked in the field;
Erosion fabric and/or straw wattles would be used to define the bank-water column interface;
Woody vegetation cuttings would be driven through the fabric and bank material, at a depth that would intercept the ground water interface provided by the creek;
Most of the construction would be done by a hydraulic excavator. Cuttings, seed, and nursery stock would be used to re-vegetate the banks with mostly native species.

We expect the side channel restoration of spawning and rearing habitat will enhance the naturally spawning populations of brown trout and rainbow (redband) trout and white fish in the Boise River. The results and lessons learned will be transferred to additional areas where habitat restoration and connectivity can occur along the Boise River. Other likely candidates include Harris Ranch (also funded in part by National Fish and Wildlife Foundation) the "daylighting" of Cottonwood Creek through Julie Davis Park in downtown Boise, improving habitat in the Loggers Creek side channel in southeast Boise, and side channels adjacent to the city-owned Warm Springs Golf Course.

Here are a couple of photos from the fall of 2001:

Questions or comments send to: boisetrout@aol.com
Ted Trueblood Chapter Idaho Trout Umlimited

Island Creek Project: Restoration Objectives and conditions in June 2002