900 Road culvert replacement spurs debate after flowable fill pour lifts one pipe

Contractors installing two new culverts on 900 Road reported the installation met permit requirements, but a subsequent flowable-fill pour lifted the west pipe and deformed the east pipe. The county—————————'s project foremen and on-site representatives described differing accounts of how the pour behaved and whether the mitigation steps taken during construction were adequate.

Chad McCullough of Kaw Valley said the crew had poured flowable fill in lifts and used block-and-formed end structures to retain the fill during staged pours. "We had talked about doing it in separate lifts...the first pour went fine, but on the second pour...it got underneath there and raised the 1 end up on the west pipe," he said. He advised options: attempt careful removal and replacement of the pipes (at risk of damage) or use the existing pipes as forms and pour concrete to encase them.

Commissioners and county staff expressed frustration about the unforeseen additional costs. One commissioner said the county was already over budget on the job, quoting a revised project total in the low- to mid-$70,000s, and warned that replacing damaged pipes could add roughly $10,000 per pipe for new material and fittings.

Questions on project oversight dominated the discussion. Commissioners asked whether county crews had adequate guidance, whether Kaw Valley had stamped a design or merely secured permits, and whether the permitting process required engineered shop drawings. Kaw Valley staff said the permit application did not require a full engineered plan for this drainage area and that much of the execution was handled in field meetings among foremen, the contractor and the engineer. The exchange grew heated as commissioners and engineering staff differed over who had final responsibility for the field execution and for the resulting additional costs.

No formal vote or contract change was recorded at the meeting. Commissioners asked staff to obtain firm cost estimates for two remediation options: (1) carefully extracting and replacing the pipes if possible and (2) completing the encasement/concrete option and presenting cost and schedule implications at the next meeting. "You can either dig out the 2 pipes super careful and hope that you don't damage them enough that you can put them back in or you can just basically use them as forms and fill the whole entire thing up with concrete," Kaw Valley said in the discussion.

Ending: Staff was directed to get concrete cost estimates and quotes for replacing pipes (including delivery and installation) and to return with those numbers so commissioners can decide how to finish the 900 Road culvert project.