Mat-Su finishes Fern Street rebuild with new Cottonwood Creek fish culvert

The Mat-Su Borough said Wednesday it has finished rebuilding Fern Street from Knik-Goose Bay Road to Mint Drive, including a new fish passage culvert where the road crosses Cottonwood Creek.

The work also added roadway improvements and a pedestrian pathway. The borough plans to upgrade Fern Street to Fairview Loop Road as an improved north-south collector route. It calls the culvert part of a broader effort to improve fish passage throughout the Cottonwood Creek drainage.

The new crossing replaces three open-bottom arch culverts that blocked adult and juvenile salmon, according to the Mat-Su Salmon Partnership. In its list of projects funded in 2025, the partnership called Fern Street the lowest remaining barrier on the creek and said it was blocking 71% of the watershed. Replacing it would improve passage for fish to more than 8.2 upstream miles and 659 lake acres, the partnership said, and give juvenile fish unimpeded downstream access to rearing and overwintering habitat.

Since 2014, Fern Street has become a major roadway with traffic that far exceeds its original design, according to a borough memo to the Assembly in April. Poor drainage, frost-susceptible soils and restricted sight distances caused frequent pavement failures and safety hazards, the memo said. The Assembly voted 7-0 on April 21 to award the construction contract to Tutka, LLC, the low bidder of eight, for about $1.9 million.

At its Sept. 15 meeting, the Assembly extended the deadline on Fern Street fish passage grant and matching money, including a City of Wasilla match, to Nov. 30, 2027. It also accepted a $45,000 U.S. Fish and Wildlife Service grant toward replacing another barrier culvert in the drainage, at the outlet of Anderson and Hart Lake.

The second phase of Fern Street, north to Fairview Loop Road, depends on funding and right-of-way.