Willows Council approves sewer rehabilitation, orders geotechnical study after state flagged nitrates

The Willows City Council on July 22 approved a resolution to proceed with a sewer rehabilitation project and separately authorized a geotechnical investigation of the city's wastewater treatment ponds after a state inspection found elevated nitrate readings beneath the ponds.

Council members and staff said the tests and the follow-up core samples are intended to determine whether the ponds are lined to current standards; if they are not, lining or other remediation could require a multi-million-dollar repair. The council approved the items as part of the consent calendar by a unanimous vote.

The sewer rehabilitation base bid shown in agenda materials was $1,000,164.80, with a 10% contingency listed at about $116,000. The construction management and inspection line item shown in the staff report was $150,000; staff discussed that figure in daily-rate terms (the agenda discussed a $2,500-a-day cap and an estimated 35 vs. 60 working days). Acting Mayor Richard Thomas said the cost to fix an uncovered lining problem could be "a 7-figure fix." Marty Brown, the city manager, told the council the geotechnical investigation would be part of a broader Prop 218 study already underway and that the engineers will include any estimated remediation costs in that work.

Council members and staff said the state's inspection included water testing under the ponds and that nitrate detections prompted the question of whether the ponds are lined. Council members noted the city lacks documentation showing a concrete liner or other visible liner and that some older ponds were sometimes built using bentonite or similar materials that can be hard to identify without core sampling. Brown said the core sampling is intended to answer that question.

Council discussion included whether the wastewater fund could absorb a major remedial cost. Brown cautioned the operating budget could not cover a large remediation if one is required, and council members emphasized the importance of folding the estimate into the Prop 218 process and the city's bond-funded capital schedule. Council members also noted the sewer rehabilitation and related lift-station rehabilitation projects are being scheduled to use bond funds that must be expended on a specific timeline; one council member said the city is under a strict timeline to spend those bond dollars.

The staff report noted the city previously upgraded the wastewater treatment facility using a USDA loan roughly 25 years ago; council members said it is not yet clear whether pond lining work was included in that previous project. The city engineer and Coastland Engineering were cited in discussion; staff said Coastland has been transparent on billing and would only bill actual hours.

The council approved the consent calendar motion, which included: adoption of a job classification for a retired annuitant library clerk; approval of a Statewide Communities Development Authority open PACE program resolution; approval of the 2024'/2025 sewer rehabilitation project resolution; and authorization of the geotechnical investigation of the wastewater treatment ponds. The motion passed unanimously.

Next steps: staff said it will finalize an RFP and/or scope for the geotechnical core sampling and include any remediation cost estimates in the Prop 218 study so the council can consider funding options.