Study: Tongass road culverts hurt fish runs

Posted: Friday, May 05, 2000

A local environmental group says a recent report shows that culvert crossings of streams in the Tongass National Forest are inadequate to ensure passage of juvenile salmon and trout.

But a Forest Service official says the agency has recognized the problem for three years and has already taken steps toward replacing problem culverts.

The Forest Service's annual monitoring report on the Tongass Land Management Plan says that only 46.8 percent of culverts across salmon streets and only 17 percent of culverts across trout streams are ``assumed to meet passage standards'' for juvenile fish.

A third of the 265 culverts on salmon streams and 70 percent of the 546 culverts on trout streams were assumed not to meet those standards, with the rest requiring more analysis.

``This report shows in black and white that Forest Service road crossings are hurting Southeast fish runs,'' said Sarah Keeney, water quality organizer for the Southeast Alaska Conservation Council. ``Culverts that don't pass fish mean less fish available for commercial, sport and subsistence fishermen.''

The issue is the size of the pipe, says Larry Meshew, an ecology officer for the Forest Service. Smaller pipes create greater velocity and make it harder for juvenile fish swimming upstream, he said.

But until the 1997 revision in the land management plan, Forest Service culvert design standards didn't take juvenile fish into account, Meshew said. Since then, new culverts are meeting the standards, and an inventory of sub-standard culverts is under way, he said.

But even the sub-standard culverts generally would have a problem only every other year, Meshew said. A two-year flood -- that is, a flood of the size that occurs on an average of once every two years -- would pose an obstacle for juveniles for up to two days, he said.

The Forest Service has $400,000 this year for culvert replacement, Meshew said. Culverts can cost $4,000 to $20,000, depending on engineering issues at the site. He estimated between 30 and 50 could be replaced with that money. Salmon stream crossings are the highest priority, he said.

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