THE TILLAMOOK BAY FLOODPLAIN

Tillamook Bay lies on the north coast of Oregon. Tillamook means "land of many waters," which refers to the five rivers that flow down from the coast range, creating a massive alluvial floodplain on their way to the Tillamook Bay. Despite over a hundred years of efforts to engineer the landscape to control the inevitable flooding that takes place almost every winter, the city and county of Tillamook continued to experience devasting floods, culminating in the great flood of 1996. In the wake of that flood's extensive devastation, many people in Tillamook decided to start doing things differently.

While there some engineering fixes are still being employed to help steer excess floodwater towards the bay more quickly during high water events, there has also been an extensive effort to restore some of the floodplain's historic abilities to absorb extra water. Which has meant in particular removing many of the buildings that built in the floodplain and even the floodway (where floodwater flows during a flood) during the community's heyday of urban expansion during the 1980s. Buildings that have not been removed - or at least vacated - there is a contentious shell of an old Safeway store that remains - have been raised up several feet so that when floods occur, they will not be innundated. As a result, Tillamook is able to ride out most floods now as nuisances, not disasters. Restoring the natural functions of the Tillamook floodplain not only helps alleviate the worst impacts of current flooding, but will also mitigate the impacts of climate change, which will cause even more extreme wind and rain storms.

This river is one of five rivers flowing into Tillamook Bay. This view during a flood in 2009 is a common site in Tillamook County.

 

This slough forms the southern edge of the floodway. The city of Tillamook, itself, is on higher ground on the south side of the slough.

A common site on Highway 101 north of the city of Tillamook. Since 1996, new bypasses north and south of town keep traffic flowing between Highway 6—running east of town over the coast range to Portland—and Highway 101, when this area is flooded.

Doug Rosenberg's family lumberyard, January 8, 2009

This open space is a wetland that was once built on. Across the highway from the old Safeway store, it could help provide better storage for flood waters if the Safeway structure were not an impediment.

 

Another solution Tillamook County has used to mitigate flood impacts is to raise buildings in the floodplain a significant height above the highest record flood event. In Nehalem, in northern Tillamook County the entire downtown has been raised up on platforms to protect the buildings from the flood-prone Nehalem River which flows behind this building.

Another view of downtown Nehalem, across Highway 101.