The successful bidder for a construction contract to repair and replace up to 40 culverts in unincorporated San Diego County will be replacing a culvert on McDonald Road and lining a culvert on Reche Road.
The San Diego Board of Supervisors voted 4-0 Feb. 15 with Ron Roberts in Washington, DC, to authorize the advertisement for bid and subsequent award of a contract to replace and repair listed culverts. The contract is structured to include a base bid consisting of 31 locations and an additive alternative, or nine locations which can be added to the contract if funding permits. The McDonald Road and Reche Road culverts are both in the base bid.
“The heavy rain we’ve been having creates water runoff that collects mud and debris and can damage culverts,” said Supervisor Bill Horn. “This $1.8 million project will repair culverts across the county with the majority of repairs being done in District 5.”
The estimated $1.8 million cost includes contingencies. A balance in the county’s road fund will provide $1,690,500 of that amount while Highway User Tax Account revenue derived from the sales tax on gasoline will be used for the other $109,500.
Seventeen of the culverts in the base bid are in the Fifth Supervisorial District, including the culvert on McDonald Road approximately 560 feet south of Fallbrook Street and the culvert on Reche Road approximately 275 feet south of Shaffer Lane. Four of the nine culverts in the additive alternative are in the Fifth District.
The county’s Department of Public Works maintains more than 18,000 drainage facilities, including more than 14,000 culverts. Stormwater crews inspect all county-maintained culverts on a cyclical basis and prioritize them for rehabilitation or replacement. Field engineering staff members inspect the culverts nearing the end of their service life to determine whether replacing the culverts or rehabilitating them with new lining would be the more preferable option.
Lining a culvert involves the installation of an internal sleeve. Lining methods include cure-in-place pipe which utilizes resin-impregnated fabric inserted into the existing culvert, slip lining insertion of solid wall surface into the existing culvert, and insertion of spiral-wound pipe which will expand and line the culvert. The internal sleeve restores the pipe’s structural integrity while reducing excavation and thus minimizing traffic impacts.
Repair of holes and the restoration of capacity without replacing the culvert can also be accomplished by invert paving which consists of preparing the invert surface area, or the bottom of the culvert, to receive concrete, installing bar reinforcement and anchorage devices, and paving the inverted area with concrete on the bottom of the pipe to fill existing holes and restore it to a structurally-sound pipe floor. If the culvert is damaged beyond economical repair, a culvert replacement is more appropriate than rehabilitation and the existing culvert is removed with a new one being installed.
The culvert repair and replacement on a countywide basis is scheduled to begin in summer 2017 and be complete by winter 2018. Traffic control measures will be implemented during the construction to limit impacts to community members and other travelers.