Fish passage closes road
A section of Rohnerville Road in Fortuna is closed to through traffic for approximately three months as the Jameson Creek fish passage improvement project gets underway. The closure between South Loop Road and Kenwood Road began last week and is slated to continue through early to mid-September.
“The city realizes that this is a highly trafficked area and that closure will certainly be an inconvenience,” said Brendan Byrd, Fortuna Deputy City Engineer. “However, due to the scale of the project and the very tight working spaces, maintaining single lane traffic during the duration of the project would likely have been infeasible, as well as posing safety concerns for motorists and the contractor.”
Through traffic will be asked to detour around the site using Redwood Way, School Street, or Kenwood Road and connections between Rohnerville Road and Fortuna Boulevard
Mercer-Fraser Company is the contractor. The company will be installing a precast concrete box culvert to replace the existing six-foot metal pipe, a portion of which failed several years ago and threatened to undermine a section of Rohnerville Road. An emergency repair at that time replaced the downstream section of pipe and the eroded roadbed embankment.
“The event did identify the need to replace the entire pipe,” Byrd said, “which in many areas was rusting away and vastly undersized to carry the amount of flow that comes down Jameson Creek during large winter storms.”
The city secured grant funding from the Fisheries Restoration Grant Program, administered by the California Department of Fish and Wildlife (CDFW) to develop and complete full designs for the project. The design process was completed in 2018. Two additional grants, another from CDFW and one from the Wildlife Conservation Board, were secured to cover the entire cost of construction, construction engineering, and permits. The total amount granted was $2.7 million, and there is no dollar match required from the city, only staff time related to project management.
“The city is very grateful to those agencies for seeing value in performing this project in the city of Fortuna,” Byrd said.
He said the cost burden for repairing the Jameson Creek culvert would have been difficult or impossible for the city to accomplish using local funds.
The box culvert to be installed by Mercer-Fraser Company will have over twice the capacity of the existing metal pipe culvert, which will allow the 100-year peak flow in the creek to pass entirely through the new culvert and not back up the upstream channel. The oversized concrete culvert will also allow for an engineered stream channel to be constructed inside. Mercer-Fraser Company will be rebuilding about 350-feet of streambed channel.
The existing metal culvert is a barrier to fish, since the creek bed elevation on the downstream end of the pipe has eroded more than seven feet below the elevation of the upstream end of the pipe.
“When the project is complete,” Byrd said, “the city will have a new stream crossing of a principle roadway that is safe, resilient, and designed to modern engineering and construction standards. The removal of the total fish barrier will provide for more upstream habitat for native and anadromous salmonids.”