Chinook culvert project completed

Chinook culvert project completed

CHINOOK — The Fort Columbia Tidal Reconnection Project, next to the tunnel approaching the Astoria-Megler Bridge, has been completed.  

One hundred years ago there was a railroad bridge where U.S. Highway 101 now approaches the tunnel. When the original culverts were put in for drainage, they were placed at a height that was not conducive to incoming water and fish passage.

A newly installed box culvert is designed to drain the 800 acres of land owned by the Lewis and Clark State/National Historical Park, into the Columbia River. This culvert is not the type of round culvert that most people are accustomed to; it is a specially designed box culvert (as can be seem in the photo above). A one-acre pond was also dug next to the box culvert. 

At the beginning of the project, after the redirection of traffic, sheet pile was sunk to dam flooding from the Columbia River, the asphalt was torn up, the sand leveled for the culvert base, the box was lowered piece by piece, then the lids welded and grouted.

They then pulled out the cofferdam at low tide, and on Feb. 17 with the incoming high tide, the inland area had its first water exchange in a century. 

The water exchange will allow salmon fry to disperse from the mainstream Columbia and seek protection in this new habitat.

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