Back in November, you may have heard a big sigh of relief on the North Coast when the Clatsop County Board of Commissioners approved a contract for a planned flood-reduction and wetlands restoration project next to U.S. 101 south of Seaside. There was finally a solution to the flooding and high standing water that has plagued motorists and the local communities for decades.
Commissioners approved a contract for Henderson LLC of Lake Oswego for $728,000 to remove earthen berms along the Necancium River and elsewhere on property owned by the North Coast Land Conservancy adjacent to U.S. 101. The project, which will restore wetland habitat while easing the chronic flooding of the highway, is being funded entirely from the Oregon Department of Transportation’s wetland mitigation bank program.
The project is a joint effort of Clatsop County, Seaside, Cannon Beach, ODOT and the NCLC and is slated to begin construction in early summer of this year and be completed by Sept. 30. The project is being described as a win-win for the local communities, ODOT, tourism, emergency service providers and anyone else who uses the highway.
High water is more than nuisance
Almost anyone who follows the news in Oregon probably knows the problem area along U.S. 101 south of Seaside (milepost 23-25). Who hasn’t seen TV crews standing next to vehicles carefully navigating their way through high water hoping they will make it past the hazard? The flooding is caused during a combined large rain event and high tide, which seems often these days. Already during the fall/winter of 2012-2013, ODOT’s District 1 maintenance crews have had to restrict traffic four times. It is not uncommon for traffic south of Seaside to be restricted or closed 6 to 10 times each winter for hours at a time.
During some high water events, the flooding could reach almost two feet forcing a full closure to all vehicle traffic. Most of the time, the water is 8 to 14 inches deep but that still restricts traffic to high profile vehicles and reduces speeds to 5 miles per hour. ODOT’s District 1 Warrenton maintenance crew is usually responsible for monitoring and staffing the high water area often having to pull motorists and their stalled vehicles out of the water. It complicates storm response by District 1 staff, who have to divide time between the many other storm-caused hazards such as downed trees and power lines, landslides and other high water areas.
The U.S. 101 flooding and high water has been a major inconvenience for citizens of Canon Beach, Seaside and other North Coast communities that are tied together closely by jobs, health needs, schools and other important services. While a detour around the flooding is possible, it could take hours instead of the usual 15 minutes or so to get to where you need to go.
For many local citizens, it seemed that the logical solution was raising the two mile stretch of highway that always flooded. But the cost for doing that would be in the millions and that sort of funding was not available. Finding a more low-cost solution was imperative.
Solution involves partnerships
In 2011, a major step was taken toward finding a solution. Local cities, Port of Astoria, Clatsop County and ODOT hired Northwest Hydraulic Consultants of Seattle, to develop mitigation alternatives. According to the study, the berms on the west bank of Necancium River confined the river during high water events and prevented excess flow from spilling out onto lower ground to the west. Removing the structures could reduce floodwater levels on the highway up to seven inches or more, according to the study’s modeling.
In the meantime, the North Coast Lane Conservancy (NCLC) owned 364 acres of land purchased in 2003 that was adjacent to the flooding area. The organization was looking to restore its rare Sitka spruce wetlands. It also knew that berms or levees that were constructed in the 1960s were having a negative impact on the ecosystem.
“The study was critical because it recommended some reasonable and affordable options to relieve the flooding,” said Larry McKinley, ODOT’s Area 1 manager in Astoria. “Raising the highway was never really a feasible solution for a number of reasons the least of which was the potential cost.”
Since ODOT’s road projects often impact waterways and wetlands, the agency is required by law to enhance wetlands
in other areas to mitigate their impact. It was fortunate timing that the agency was looking for a sizeable chunk of land to develop a wetlands bank in the Necanicum Watershed area. Around 100 acres of the NCLC’s land will be used as an additional water storage area.
By removing the berms, the excess water can expand into the natural wetlands. This will restore the wetlands by soaking the land while creating new streams and side channels. Fish and other wildlife benefit; motorists benefit because water that was flowing on to the highway will stay where it is supposed to…..in the wetlands.
While the completed project is not expected to completely end all high water events, it is expected to reduce nuisance flooding by more than 50 percent making the roadway passable for most vehicles and reducing restrictions. The thousands of motorists and others who depend on that stretch of U.S. 101 as a lifeline to North Coast communities can’t be more pleased.