East Twin Creek, is a
second order tributary to the lower Blackfoot River with base flows of approximately 6
cfs. A perched 8' x 64' culvert on Champion International property limited fish
passage to base flow periods for approximately 25 years. Flow velocities were
recorded in excess of 10 feet/second in June 1997. The culvert was removed in the
fall of 1997.
Undersized and perched culvert prior
After the culvert was removed and
banks sloped back.
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. East Twin Creek is ranked 31 of 83 streams surveyed. Fish populations
were sampled above the culvert crossing before and after removal of the culvert. In
the 1998 survey, a single bull trout was collected in the sample upstream of the old
culvert. Four samples in 1996 in East Twin Creek recorded no bull trout
presence. The fish is thought to be a juvenile fish from the Blackfoot River using
this stream for rearing and thermal refuge.
A temperature data logger (hobo) was
placed near the mouth of East Twin Creek the second week of May and pulled the second week
of October 1998. The mean summer temperature for the four-month period of June
through September was 51.3 degrees Fahrenheit. Maximum monthly summer temperatures
remained cool ranging from 53.6 in June to 58.4 in September. Maximum summer
temperatures were 10 degrees below Blackfoot River temperatures at Wished Bridge (56.2 vs.
66.7), indicating that this stream provides significant cool-water input during high
temperature periods in the lower Blackfoot River.