Lodge Creek Culvert Replacement

This project replaced the existing 4-foot diameter corrugated metal pipe culvert that conveyed Lodge Creek under Via Kachess Road but failed during heavy rains in early spring 2016—undermining the existing road fill and pavement.

The project required close coordination with resource and regulatory agencies to meet the aggressive four-month design and construction schedule. This required regular coordination meetings with Kittitas County, the USACE, DOE, WDFW, USFWS, NMFS, USFS, and Yakama Nation. This coordination included developing a multi-disciplinary team consisting of experts in design (e.g., geotechnical, structures, roadway, and construction), environmental (e.g., biology, permitting, and cultural resources), and construction.

Fine silt and organics lay under the embankment. There was also a high value wetland upstream of the existing failed culvert and a degraded scour condition downstream of the roadway. The downstream condition created a plunge pool fish passage barrier—which adversely impacted stream and riparian habitat—and had a risk of draining the upstream wetland if not designed and constructed to avoid head-cutting and channel instability. In the initial workshop, careful consideration was given to the proposed open-bottom design. It was determined that a four-sided box culvert would mitigate many of the associated geotechnical risks. Based on production rates observed during the recently completed Jovita Creek culvert replacement project in Auburn, WA, Atkinson proposed a three-day roadway closure to facilitate the removal and installation of the new culvert. As part of the project, a new 40-foot-long, 19-foot-wide, closed-bottom, four-sided precast concrete box culvert was installed, along with the restoration of upstream and downstream riparian habitat. This new culvert significantly improved the conveyance of large Lodge Creek flow events and enhanced fish passage. Additionally, it ensured reliable residential and emergency access to homes along Lake Kachess.