Contract Description:
This Statement of Work addresses the objectives and tasks of the 19th 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 FY11 focused on continued monitoring of the Spring Creek sites and implementation. Restoration/ enhancement efforts in FY12 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. Of particular importance beginning in late FY11 and through FY12 will be the Fort Hall Bottoms Tributary Assessment. This project will be very similar to the Yankee Fork Restoration Project also a BPA funded Contract. The scope will be to utilize a suite of attributes to capture existing conditions of riparian and stream habitiat, limiting factors, population dynamics of yct and trout, and include mapping of each stream. The end product will be a guidance document which will identify priority areas for project implementation on the Bottoms. Also, this will further guide through compiled information during the Assessment of limiting factors which will be looked at more closely such as populations of trout and hydrology of the Uppersnake Watershed and how it affects the Bottoms. These will need to be looked at more closely and may require at least two years to complete.
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). These will be continue as in years past. Also, work will begin to establish a minimum flow on the lower Portnuef river which will include temperature data, and water chemisry and will include meetings with Tribal Water Resources and Bureau of Indian Affairs.