An agreement between Clatsop County and the Oregon Department of Transportation approved Wednesday by the board of commissioners opens the way for a long-awaited project to relieve flooding on U.S. Highway 101 near Seaside.
The county will now seek contractor bids for the project, which involves the removal of an earthen berm and fill material along the Necanicum River. Permitting and final designs have been completed, and the board will likely choose a contractor in November – actual construction will be weather-dependent.
The work is a joint effort of Clatsop County, ODOT and the North Coast Land Conservancy designed to ease chronic wintertime flooding along a roughly one-mile stretch of the highway south of Seaside, while at the same time restore wetland habitat on a Conservancy-owned piece of property.
The project, with an estimated cost of $1.1 million, will be funded through the state's mitigation banking program, which pays for the restoration and preservation of wetlands and other sensitive natural resources. The work will open up to inundation about 110 acres of adjacent land within the Land Conservancy's Circle Creek habitat reserve, and contribute to the group's goal of re-establishing wetlands and riparian forests on the entire 364-acre site.
The agreement approved Wednesday details the parties' respective roles, with Clatsop County responsible for putting the project out for bid.
The project originated from a 2011 hydrological study funded by Clatsop County, ODOT, the Port of Astoria and cities of Astoria, Cannon Beach, Gearhart, Seaside and Warrenton that examined the almost yearly incidence of flooding. Heavy rains combine with high tides to send water over the banks of the Necanicum and across the highway, and the flooding frequently leads to traffic restrictions and occasional closures of the roadway.
The work will remove a section of man-made berm on the river's western bank as well as some old road fill. This is expected to allow water to more easily flow into the adjoining land and reduce or eliminate high water on the highway.