Mat-Su Borough approves salmon protections for culverts

Photo/Patty Sullivan/Matanuska-Susitna Borough

As fishing organizations throughout Southcentral gear up for the contentious Cook Inlet fisheries meetings this winter, the Matanuska-Susitna Borough has taken its own action toward improving fish runs.

In August, the Mat-Su Borough Assembly passed an ordinance requiring fish-friendly culverts for new roads that cross anadromous water bodies.

That came after about a decade of work to improve fish passage throughout the borough by several partners.

During 2013, the borough replaced three culverts, reopening more than 13 miles of upstream habitat, according to Bill Rice, who works on culvert issues through the U.S. Fish and Wildlife Service. In the next two years, at least six more culverts are fully funded for replacement, Rice wrote in a Nov. 5 email.

About $6 million has been spent at 80 sites so far, mostly on Mat-Su Borough roads, but also including work with private landowners, Rice wrote.

At a Nov. 5 assembly meeting, the borough took the next step by accepting money from the legislature intended for work to improve fish passage.

The borough received $2.5 million at that meeting for “fisheries and fish protection,” but did not come to an agreement on how much will be used for fish passage, or culverts, and how much will be used for genetics. The Anchorage Daily News reported that initial discussion looked at spending $900,000 on culvert work.

No matter how much is spent, the borough’s workload will start to lighten as old culverts are replaced, and the new ones won’t have to be.

Most of the problem culverts, Rice said, are those built 30 or more years ago. Back then, they were built to withstand 10- to 25-year water flows, and as a result, cannot always handle larger amounts of water.

“This may be a result of sparse data compared to now, as we now have a much better idea of flood flow magnitude than ever before,” Rice wrote.

The new standards mean that borough roads now must have a larger culvert that enables salmon to swim through it if the road crosses an anadramous stream.

The new standard is part of the borough’s Subdivision Construction manual.

Frankie Barker, an environmental planner for the borough, said a committee that looked at the manual as a whole developed the standards. Members of that committee, which was convened by the Public Works department, included borough engineers, private contractors, and U.S. Fish and Wildlife Service personnel.

“The standards were based on the procedures used to size culverts for culvert restoration projects,” Barker wrote in an email.

Rice said modern culverts are generally built for 50- or 100-year flows.

There’s also a side benefit to culvert replacement, according to both Rice and Barker.

During the 2012 borough flood disaster, none of the restored culverts flooded because they had enough room for the water to flow.

“This fact helps immensely to keep roads open during large flood events, helping reduce costs to infrastructure and assisting emergency services with public safety issues during large floods,” Rice wrote.

The culvert replacement effort is part of a partnership between the borough and several other entities that addresses salmon habitat issues.

The Mat-Su Basin Salmon Habitat Partnership identified fish passage as an issue for salmon in a 2008 strategic plan, and has been working to address that for the past several years.

Culvert work has included replacing smaller culverts with larger ones, such as at Cottonwood Creek, or replacing arches with bridges, such as at Wasilla Creek.

In 2010, there were $1.2 million in active grants for culvert work throughout the borough.

Other entities, including The Nature Conservancy and the Chickaloon Village Traditional Council have also worked with private landowners on culvert replacements, Barker wrote, including on some driveways.

The Alaska Railroad Corp. has also participated in some fish passage work.

Last year, the railroad worked with the Alaska Department of Fish and Game to replace a culvert with a bridge at Sunshine Creek, which has a significant sport fishery, according to Rice.

The ordinance passed with support from a host of organizations, including the borough’s planning commission, the Mat-Su salmon habitat partnership, the Alaska Salmon Alliance, and others.

Upper Cook Inlet salmon runs have been limited for years, and the borough is just one of several organizations interested in trying to restore them. Although the culvert work improves fish passage, the borough is quick to note that it believes the issues with salmon returns are not solely problems with habitat — and culverts are not the only habitat issue at play.

A June 2013 report by the United Cook Inlet Drift Association attributed most of the issues to habitat and other problems, like the Northern Pike invasion, parasites and beavers, but the borough wants to do further research to find out what is going on in the ocean.

The legislative funding the borough received will also go towards looking at what happens when salmon bound for Cook Inlet spend time in the ocean. The borough wants to know the path salmon take as they swim up the Inlet.

Molly Dischner can be reached at [email protected].

11/14/2013 - 7:11am