Notice of Upcoming Project
Posted by City Hall on Mar 20, 2024
The City of Vernonia is undertaking a project to improve its sanitary infrastructure. This notice is being posted in advance of the Request for Proposals to give contractors added notice about this project. This notice shall serve only to provide general information about the project. Anticipated publishing of Request for Proposals is expected to occur on April 2nd, 2024 and may be found at djcoregon.com. The anticipated start of construction is June 1st, 2024.
Project specific inquiries will not be answered prior to publishing the Request for Proposals.
Project Location Vernonia, Columbia County, Oregon, Township 4N Range 4W Section 4 Coordinates within 45o51’52”N and 45o51’17”N; 123o11’00”W and 123o11’50”W HUC12: 171002020106 (Lower Rock Creek) / 171002020109 (Coon Creek-Nehalem River) Within City of Vernonia limits, majority of work to be done West of Rock Creek
See project map HERE
Project Description This project is characterized as a Linear Infrastructure Project focusing on the City’s sanitary sewer system. It is intended to improve the flow capacity of the Springboard Ln and Clatsop St sewer lines. Current pipe capacities do not meet the demand and at times of extreme flow, there is sanitary sewer overflow (SSO) near the Clatsop St system. This overflow, the under-capacity system, and the associated wear these elements cause on the overall system are health and safety issues which the City is working to eliminate. As the current sewer crosses Rock Creek and Bear Creek it also creates fish passage barriers inhibiting the natural migration of several fish species.
Work to increase system capacity in the faulty areas will consist of replacing existing pipes and manholes with larger sized pipes at greater slopes. A new connection from the area of systemic SSO will be made to this upsized sewer line and the existing connection in this area will remain as a secondary outflow in the case that the manhole was to backup. In addition to this upsizing, a new sanitary pump station will be installed at the reasonable end of this system’s gravity line. This new pump station connection will take the place of the existing system’s connection to an eastern pump station which also services the central portion of town. By splitting these connections, each individual system will have a lesser load to handle and greater capability to manage anticipated sewage flows. This reconnection is also necessary in order to remove the Rock Creek and Bear Creek fish passage barriers.
By routing the town’s western sewage into its own pump station, the east-west connection to the existing pump station can be disconnected and the associated pipe work can be removed from Rock Creek. Demolition of this infrastructure and additional creek bed grading will restore creek hydraulics and geometry to functionally provide fish passage. Similarly, the existing sewer, where it crosses Bear Creek, daylights and poses a fish passage barrier. This stream crossing is directly adjacent to the failing culvert in the Adams Ave ROW which also creates a barrier. In conjunction, the pipe and culvert will be removed and replaced with renovated sewer piping and a spanning bridge. The creek bed in this segment of work will also be restored to provide natural passage upstream.
