Sweet Creek Road

DOWL provided design and construction engineering for the replacement of this 1,120-foot-long retaining wall along the Siuslaw River in Lane County. After working with Lane County on three engineering studies in 1995, 1997, and 2000 to assess failures of the wall, the county selected DOWL to provide final design of a solution to stabilize the road, reduce county maintenance costs, eliminate the risk of future catastrophic failure of the wall, and to provide all-season access for residents and travelers.

Failure of the structure had led to failure of the road fill and would have effectively cut off the area served by Sweet Creek Road, a lifeline route to 68 private residences beyond the project area, as well as access to 30,000 acres of national forest lands. A catastrophic failure would also discharge fill into the Siuslaw River. Originally envisioned as a retaining wall replacement, the Sweet Creek Road project eventually evolved into a complex 15-span bridge in order to maximize its effectiveness in preventing further landslides at the site and maintaining access. It is now the longest bridge in the county’s road system.