Mill Creek makeover to improve fish habitat

The main purpose of the Mill Creek flood channel will remain the same.

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Framed through the holes of a perimeter fence along Mill Creek, huge chunks of concrete have been cut out and moved from the bed and sides of the creek as part of work to improve the channel for steelhead and bull trout.

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Perhaps sensing the improved flow of fish through Mill Creek with work being done in the channel east of the Roosevelt Street bridge, a great blue heron stands patiently waiting for its next meal as the creek flows from a bypass tube at the upper right.

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Work is being done in Mill Creek (photographed from Roosevelt Street bridge) to improve channel for steelhead and bull trout.

WALLA WALLA - Work on two of three Mill Creek construction projects is moving along at a rapid flow, as contractors work to meet a two-month deadline to finish more than $500,000 in fish habitat improvements by the end of October.

"Fish managers believe that upper Mill Creek is very good fish habitat," Tri-State Steelheaders project manager Brian Burns said, adding that for a number of years scientists speculated as to why the upper Mill Creek failed to produce good numbers of spring chinook or summer steelhead.

"It is believed that passage through lower Mill Creek is the issue, and we never had anything more than opinion and anecdotal information as to why," Burns said.

After years of speculating and funding a study to design ways to improve fish habitats in flood-control channels, a proposal by the Tri-State Steelheeders to improve fish passage on three sections of lower Mill Creek was approved and funded.

A total of $590,000 in state funds will pay for the three projects, with a 15 percent matching grant provided by the Confederated Tribes of the Umatilla Indian Reservation, Burns said.

Earlier this month, contractors started cutting away concrete and reforming channels on Mill Creek at Roosevelt Street and Ninth Avenue; this week crews are expected to begin work on the Tausick Way project.

Depending on which site, the projects will either slow down or speed up the flow of water, and in all three the changes will help retain deeper pools of water all year.

"A lot of what we are doing when we are done most of the time it will be under water and you won't even see it," Burns said.

At the Ninth Avenue project, where the water runs notoriously fast during spring runoff and is almost bare during late summer, baffles and pools will be added to create eddies where fish can rest from the currents during high flow and water can collect during drier months.

At the Roosevelt Street project, where Mill Creek spreads out into a wide shallow flat, crews have already dug out large sections of a flume that will eventually narrow the creek and speed up water flow; baffles will also be added to create protective eddies and pools.

At Tausick Way, several of the picturesque creek-spanning water weirs will be notched, thus creating a main channel where water will flow faster and deeper.

Though the work will undoubtedly change the look of the river for those sections, Burns said the main purpose of the Mill Creek flood channel will remain the same.

"That has been one of our design problems, to provide passage but not create a flood problem," Burns said, adding that each project had to be approved by the U.S. Army Corps of Engineers.

"In some cases we may actually be improving the capacity of the channel," Burns said.

All three projects must be complete in a narrow two-month window between the end of August and the beginning of November so fish runs will not be harmed, Burns said.

The Tri-State Steelheaders is a 45-year-old organization that was formed as a sportsmen's club in 1965.

In 2000 the club reformed into a fish enhancement organization with more than 200 members.

The group has already overseen several fish habitat improvement projects, including the removal of the Kooskooskie dam on upper Mill Creek in 2009.

Alfred Diaz can be reached at alfreddiaz@wwub.com or 526-8325.

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