County reports pilot fiberglass culvert lining on Donald Street, three culverts cost about $82,000

Black Hawk County engineers updated the Board of Supervisors on April 29 about a pilot program to line deteriorating concrete culverts using a fiberglass liner cured with a UV light train, a process intended to seal joints and avoid costly excavation and traffic closures.

Assistant county engineer Ryan Brennan described the technique: crews pulled a flexible fiberglass liner impregnated with epoxy through existing pipes, inflated it using bulkheads, and cured the liner in place using a UV light vehicle that travels through the pipe. The process preserves the existing pipe and, officials said, allows lanes to remain open with flagging in place rather than closing the roadway and excavating.

Work completed: crews lined three pipes — two on Donald Street and one on Raymond Road — in roughly half a day. County staff reported the combined cost for the three liners was about $82,000. Engineers said they will do an additional over-liner later in the summer for a longer section on Donald Street and continue to evaluate the method’s cost-benefit over time.

Cost context: Brennan said replacement pipe and excavation costs vary widely by site and depth — pipe material might cost $10,000–$15,000 for common diameters but total replacement including excavation and patching can reach $100,000 or more for deep, high-traffic sites. The vendor representative quoted an expected life extension of up to 100 years; county staff said they will monitor actual performance and evaluate tipping points for replacement vs. relining.

Ending: Supervisors asked about life expectancy and costs for full replacements; staff said the lining is a useful tool to repair separations in older concrete pipes while minimizing traffic impacts and will be considered alongside other methods in future projects.