Humboldt County approves pipe-lining quote to repair roadside drainage

Humboldt County supervisors approved a contractor quote from Subsurface Incorporated to rehabilitate multiple damaged road-crossing drainage tiles using a cured-in-place poly liner system, with two sites removed from the contractor scope and county forces assigned to traffic control.

The action follows staff presentation describing roughly nine problem sites inspected after heavy spring rains left some cross pipes underwater. Staff recommended removing two locations (referred to as sites 11 and 12 in the quote) from the contractor bid and instead performing an open-cut concrete replacement on one of those roads using county crews, which staff said would save about $10,500 on the contract line item.

Staff described the lining method as a reinforced poly liner inserted into the existing tile, inflated, then cured with ultraviolet light to form a continuous interior liner that avoids joint separation and prevents further breakdown of clay or concrete pipe under roadways. A rough earlier estimate cited in discussion was about $10 per inch per foot (about $120 per foot for a 12-inch pipe), but the current contractor quote came in higher, around $180 per foot for some pipes.

During discussion staff said the final price would vary depending on site conditions, notably whether dewatering is required. Dewatering charges would be prorated based on how much water contractors encounter. Staff also said the county would provide traffic control for the two removed sites and estimated the contractor work for each site could take multiple days depending on conditions; the contractor indicated work could proceed in cooler, overcast conditions and might be scheduled by the end of the month, weather permitting.

A motion to approve the Subsurface Incorporated quote with sites 11 and 12 struck from the contractor scope and with county forces to handle traffic control was made and seconded and approved by the board.

Implementation details noted in the discussion included: county crews providing traffic control (three workers and two equipment operators, stop/slow paddles), a short site repair to reconnect existing tile to the new liner after installation so lines could carry water immediately once reconnected, and the contractor’s inspection (camera) and post-installation verification.

The board did not specify a dollar total in the motion; staff provided per-foot figures and the $10,500 savings estimate tied specifically to removing the two sites from the contractor’s scope. Timing and final invoicing were described as weather- and site-condition dependent.