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North Fork of the Blackfoot

Location map for the North Fork of the Blackfoot River

North Fork of the Blackfoot River photoThe North Fork of the Blackfoot River, is a 4th order stream and is the largest tributary to the Blackfoot River. The North Fork drains the western slopes of the Continental Divide in the Scapegoat Wilderness Area flowing 34 miles before entering the Blackfoot River at river mile 54. Discharge was 300 cfs near the mouth on August 16, 1989.  The cold water temperatures of the North Fork significantly improve the health of the aquatic community in the Blackfoot River below the North Fork confluence. Although the North Fork below the falls has sections of slightly meandering alluvial bottom, it is generally confined to a narrow valley with a bed morphology dominated by highly variable boulder materials, bedrock, rapids and irregularly spaced plunge pools. 

The North Fork Blackfoot River is one of the most important spawning tributaries used by fluvial bull trout in the Blackfoot River Basin. 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. The North Fork is ranked 1 of 83 streams surveyed.

Restoration efforts in this tributary have primarily been done in cooperation with irrigators to eliminate fish losses to irrigation canals. Fish screening devices have been installed on all five canals located between river mile 8.0 and 15.3.

The three different types of screens used on the North Fork include:

(1) Drum Screen

Drum screen on the North Fork For more information on this project, see:
Irrigation Diversion Fish Screening "Helping to Save the Bull Trout"

(2) McKay Self-cleaning Paddle Wheel

McKay self-cleaning paddle wheel on the North Fork of the Blackfoot River McKay self-cleaning paddle wheel design that we have on three of the ditches.

(3) Infiltration Gallery

Before restoration photo on the North Fork During restoration on the North Fork
Before restoration on the North Fork. During installation of the infiltration gallery.
After restoration on the North Fork photo Headgate for the infiltration gallery photo on the North Fork
After completion of the infiltration gallery. Headgate for the infiltration gallery.

Three levels of fish sampling have been undertaken on the North Fork:

1) bull trout spawning surveys (redd counts)

Bar graph showing bull trout redd counts increasing from 1989 to 1998

2) pre-and post-project relative abundance of juvenile bull trout along the channel shoreline

Bar graph showing increases in bull trout juvenile catch after screening irrigation canals

3) mark-recapture populations estimates in the lower reach of the North Fork (from river miles 2.1 to 5.9)

bar graph showing bull trout density increases from 1989 to 1998

Livestock management has also been improved along eight miles of the North Fork's riparian corridor.  Conservation easements are currently in place along 9 miles of the North Fork.

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Blackfoot Valley Watershed
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