The Columbia River Estuary Study Taskforce (CREST) partnered with the Bonneville Power Administration and nearby landowners to improve aquatic habitat at four locations along the Columbia River in northwestern Oregon. The work created a new opening through the Genesee & Wyoming railroad embankment, providing migrating juvenile salmonids with access to approximately 24 acres of wetland habitat. The project increases wetland capacity and improves hydrologic connectivity.
The four locations included Agency Creek, Warren Slough, Aldrich Slough and Wolf Bay near Astoria, Oregon.
As part of the improvements, Hanson served as a subconsultant to Inter-Fluve, Inc., providing design services for two water conveyance railroad structures at Agency Creek and Warren Slough that facilitate water flow through the railroad embankment.
Hanson’s team provided design, plan preparation, bidding, rail coordination support and construction support and observation for the structures. Hanson designed each bridge with an opening modeled after the previously upgraded bridges at Wolf Bay. Each bridge included using 30-inch-deep, railroad industry-standard precast, prestressed concrete beams with matching substructure components.
At Aldrich Slough, Hanson also provided design, plan preparation, bidding, rail coordination support and construction support and observation for a new large-diameter double culvert.
