Shanley Creek, a second-order tributary
to Cottonwood Creek, flows south nine miles through forested mountains and low-relief knob
and kettle topography, including alluvial outwash. It enters Cottonwood Creek at
river mile 5.6 with base flows of approx. 2 cfs. Land use in the drainage consists
primarily of timber harvest in mid to upper portions, and livestock grazing and hay
production in mid to lower portions. In order to prioritize restoration resources, we
developed a fisheries-based restoration priority scorecard, based on biological, social
and financial considerations, for 83 impaired tributaries of the Blackfoot River. Shanley
Creek ranked 21 of 83 streams surveyed.
Three irrigation diversions and one
irrigation pump pull water from the lower 1.6 miles of Shanley Creek. We have
documented fish loses on two of the three diversions. The harvest of riparian timber has
reduced recruitment of large woody debris to the channel, simplifying habitat. Livestock
grazing has also damaged streambanks and caused sediment to accumulate in portions of
lower stream reaches. Bollman (1996) reported moderate impairment to macro invertebrate
community in the lower reach.
The University of Montana, Montana
State University, Montana Fish, Wildlife and Parks and the U.S. Fish and Wildlife Service
are cooperating on two projects to improve riparian areas and fisheries in the Shanley
Creek drainage. An exclosure fence was constructed on the lower 0.5 miles in 1994 to
measure the effect of livestock grazing on the riparian plant community. In 1993, we
established a monitoring section in the degraded section of Shanley Creek prior to
livestock grazing changes. In 1993, we sampled 0.0 westslope cutthroat trout/100
feet. In 1996, we began to pick up westslope cutthroat trout in our surveys, and in 2001
we collected 1.1 fish/100 feet.
A second project involved constructing a self-cleaning paddle
wheel-driven fish screen on a diversion canal to the Bandy Reservoir. This screening
device is designed so that approach velocities will not exceed 0.4 feet/second at the
screen, thereby reducing potential impingement of young-of-the-year fish. This
screening device has a by-pass feature that allows uninterrupted downstream movement of
fish once screened out of the canal.