Contract Description:
This Statement of Work addresses the objectives and tasks of the 18th 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.
Activities in FY10 focused on continued monitoring of the Spring Creek sites and implementation. Restoration/ enhancement efforts in FY11 will be focused on other sites on the streams Diggie Creek, Spring Creek, and Bannock Creek on the newly acquired property for wildlife mittigation, all Bottoms streams bank erosion attributes. The primary objectives will be the same as in previous years, protect and enhance utilizing rock log deflectors, bank sloping and revegetation and fencing of the project site. Therefore, restoring the stream bank will decrease channel width thus increasing depth and velocities of stream currents aggrading sediments thus cleaner gravels for spawning habitat and deeper habitat for refuge for larger trout. 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. Other projects to be completed by fall of 2012 is the Bannock Creek Project which will include a settlling pond, log weirs and rock deflector placement to aggrade sediments. New Projects will also include assessments of Diggie Creek and Jimmy Drinks on the lower Portnuef on the Bottoms for baseline data and implementation of bank stabalization projects on these areas. Also needed is a comprehensive needs analysis of the Bottoms in regards to priority areas for rationale for project implementation throughout funding commitments in the life of the Accords which will begin in end of FY10 and continue through FY11.
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). FY10 (June 30, 2011) will mark the first completion of a large scale habitat restoration project for Project 199201000 in which 80m of stream bank were restored utilizing heavy equipment (full report to bpa summer of 2011). Projects of this magnitude will be proposed to be implemented in the future.