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U.S. 101: Manzanita Ave - Neahkahnie Creek
Preliminary conceptThe purpose of the project is   two-fold:
  • replace the failing culvert at Neahkahnie Creek that has reached its useful life, and
  • install left-turn improvements at Laneda Ave. and Manzanita Ave. as included in the City of Manzanita’s Transportation System Plan (TSP).
According to the ODOT maintenance inspection report dated Oct 14, 2008, there is distortion at the seam (bulge) in bottom on corrugated metal pipe (CMP), with a 5 foot section of the invert completely rusted through. Approximately 100 feet near the culvert midlength is "egg shaped". The culvert will be inspected every 24 months. Neahkahnie Creek is listed on the Oregon Department of Fish and Wildlife as the highest priority for fish passage due to excellent spawning habitat within the upper reaches of the existing lake. The existing culvert is 460 feet long, has a steep grade (causing high water velocities) and the outlet is perched above the stream channel. These conditions are barriers to juvenile fish in reaching critical habitat. The replacement culvert will be 270 feet long and 15 feet in diameter and will be located within the road prism. The remaining 400 feet of culvert will be replaced with a "natural" stream channel that will extend up to the outlet of Reinhart Lake. 
The Modernization improvements at Laneda Ave. and Manzanita Ave. was recommended by the NW Area Commission on Transportation (NWACT) and approved by the Oregon Transportation Commission (OTC) for the 2008-2011 Statewide Transportation Improvement Program (STIP). Improvements include constructing left-turn storage lanes at both intersections with U.S. 101 north bound, improving pedestrian facilities, restriping, upgrading signage and guardrail. Designing to full standards is not possible due to constraints of the existing alignment. An exception was granted by the State Roadway Engineer for reduced shoulder width/shy distance, horizontal and vertical alignments, spiral length, and taper rates.
Checking the five year history (1/1/2003 – 12/31/2007) adds one injury crash into a fixed object with two moderate injuries. This was an out-of-state south bound semi-truck that lost control and overturned within the curve in June 2004. Adding an additional left turn lane, correction of a poorly configured left turn lane, using standard travel and median lane widths and flattening an existing 28 degree curve to a 20 degree curve will contribute to a potential decrease in crash rates.
ODOT is reviewing two construction techniques to replacing the culvert. Option 1, build a temporary structure on grade of highway over the culvert and perform the work under the structure with all lanes open on highway 101. The temporary structure will keep traffic above the work area while the culvert is being replaced and the new stream channel is being graded. Option 2, close the highway completly and perform a " cut and cover" to replace the culvert. Traffic would be detoured via Classic Street and Necarny City Road. Option 1 would take place during the in-water work period July 1 to September 15. Option 2 would take place in early Spring before the heavy tourist season begins.
Funding for this project comes from the Fish Passage ($3.2M) and Modernization ($3M) programs. Detailed cost estimates are pending. We expect to begin construction in mid-2012.

Public Involvement
The ODOT team is working with local stakeholders, City of Manzanita, and Tillamook County on the preliminary design for the project.  The public is welcome to attend ODOT sponsored open houses.  Check back to this web site for upcoming meeting dates and locations.

Upcoming Meetings
No scheduled meetings at this time.

Project Library
Preliminary concept
Open House Materials (June 2010)
Project Background | Preliminary Roadway Design 
Preliminary Construction Staging Options | Environmental  

Please contact the Project Leader with questions or comments. Media inquiries should be referred to the Public Information Officer.