This Statement of Work addresses the objectives and tasks of the fourteenth year of Project Number 92-10, Fort Hall Reservation Stream Restoration.
The Fort Hall Indian Reservation is located in southeastern Idaho, near Pocatello, and covers roughly 544,000 acres.  Reservation surface-water resources are two large, mountainous watersheds drained by the Blackfoot and Portneuf rivers which eventually flow through the Snake River plain and enter its channel at river miles 750 and 726.  Ferry Butte, at the confluence of the Blackfoot and Snake, is the northern boundary of an undeveloped 29,000 acre prairie draining numerous springs known as the Fort Hall Bottoms.  These spring streams flow southwesterly into the lower channel of the Portneuf River, where 27,000 acres of the Bottoms have been flooded by American Falls Reservoir.  The primary goal of the project is to restore fluvial salmonid habitat that has been degraded by past anthropogenic uses, primarily agriculture, irrigation, livestock grazing, and impounded and regulated river flows.

This area of Spring Creek is in the upper reaches approximately .35 miles north of Shoemaker Bridge and .25 miles south of Baker Bridge.  Access to this area will be at through the Romazetta Sheppard (deceased) residence and pasture, currently occupied by her sons, McDonald and Cody Blackhawk.  Approximately 7 dilapidated cars and appliance remnants have been placed in stream channel as a makeshift armoring or riprap along the east bank.  Over the past 15 years, the scouring effects of currents have back-cut and eroded the stream bank behind the cars.  As a result the stream channel has widened thus lowering stream depth which decreased habitat for large trout.  Other effects such as water quality, and decrease in spawning substrate due to increased sediment for sloughing banks is also a concern.  Because this site is also pasture area for the land owner, over-grazing may be impacting stream bank stability thus further contributing to erosion and sloughing. Currently, this area of Spring Creek is limited in adult trout habitat.  Because of the increase channel width due to erosion, the depth cover for large trout is minimal.  Large trout >400mm (over 16 inches) were common in this section, “highest densities of trout >400mm sampled on Spring Creek” (Doug Taki, Tribal Biologist).  Length frequencies and abundance for trout in this area have decreased from 250mm-500mm to 150mm-450mm and 40trout/100m to 18trout/100m respectively, thus becoming the lowest in frequency of trout over 400mm.  Therefore, restoring the stream bank will decrease channel width thus increasing depth and velocities of stream currents.  These further results in a more dynamic environment as opposed to a habitat that has limited cover and slower water velocities.  Although benthic invertebrates appear to be abundant “trout movement to deeper and faster water may not be related to food alone, such movement could also be explained as cover related.”(Hunter, 1991)  These areas could be described as having large boulders, rubble, depth >1.0 feet, and high velocities.

In other studies instream structures have increased pools, usable spawning gravel, and undercut banks in an Oregon stream (House and Boehne 1986) and salmonid biomass in two Arizona streams (Rinne 1981).  Numerous examples with beneficial results have been shown using structures in Danish watercourses to restore meanders, banks, riffles, spawning gravels, deep pools, water quality, and fish passage (Madsen 1995).  Stream bank revegetation combined with fencing to exclude livestock has had widespread success in improving riparian vegetation, bank stability, water quality, stream morphology (Madsen 1995; Clary and Webster 1989; Duff 1977) and avifaunal diversity (Dobkin 1998); and although more difficult to prove, well designed studies have shown an associated increase in trout biomass (Madsen 1995; Platts 1981; Platts and Rinne 1985).  Well designed instream structures are expensive and must be considered as part of an overall plan which considers factors which initially produced poor habitat  (Cederholm et al. 1997).