
Gold Creek is a third-order
tributary to the lower Blackfoot River. It flows 18 miles south through a glacial
valley, entering the Blackfoot River at river mile 13.5 with base flows of 20-25 cfs. The
Gold Creek channel is stable, well-armored, and confined in most reaches. However,
the harvest of riparian conifers and the removal of large instream wood from the lower
channel has reduced the diversity in the stream. A 1990 survey showed the lower three
miles dominated by low-gradient riffles averaging 661 feet in length, with one riffle
extending 2,400 feet. 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. Gold Creek ranked 11
of 83 streams surveyed.
Restoration efforts
focused on enhancing step, plunge and lateral scour pools for Rosgen B2, B3 and C3 channel
types. We calculated the maximum expected pool frequency of one pool per 200 feet of
channel, using a Rosgen formula, where distance between pools equates to 5 to 7 times
bankfull stream width (Rosgen 1996). In 1996, approximately 200 large conifer logs
(30 to 40 foot stems, 15 to 36 inch diameter), and 40 rootwads were placed in the channel,
enhancing or creating 67 habitat structures in the lower three miles.
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| Gold Creek after restoration |
The percent surface area
comprised of pools increased from approximately 3% pre-treatment to 13% post
treatment. Three types of monitoring have been undertaken regarding the Gold Creek
Project:
1) monitoring of habitat structures

2) fish sampling before and after
stream restoration

3) radio tracking fluvial bull and
cutthroat trout.
Eight months after the project was
completed (June 1997), an estimated 50-year flood event passed through the project
area. Monitoring has shown 85% of the habitat structures remained intact and stable
following the flood event with laterally confined reaches retaining more pools than
laterally extended reaches. Radio telemetry studies have indicated use of the
habitat structures by both bull and cutthroat trout from 1997 to 2001. |