Libby officials outline repairs, testing timeline as boil order remains after Dec. flood

City officials told the Libby City Council that emergency work to stabilize the Lower Flower Creek intake and restore head pressure after a Dec. 11 storm should allow officials to begin focused testing and, within days to weeks, seek to downgrade the community's boil order.

The City Administrator briefed the council on extensive damage to the northern retaining and wing walls at the lower reservoir and explained how overtopping and scour increased turbidity and caused a groundwater "boil" that washed sediment into the intake. As a temporary measure, crews removed intake boards, installed a bypass pipeline and constructed a temporary copper-style cofferdam and orange bypass line to route water to the plant while protecting works in the lower basin.

"We're gonna try to get that reduced to a health advisory by the fifteenth," Mayor Taylor said, summarizing the city's near-term goal. The administrator added that the temporary bypass was producing turbidity readings of about "3 to 4 NTUs" after earlier spikes of 7 to 9 NTUs; by comparison he said a good summer day averages about 0.26 NTU and the system can "barely handle 15 NTUs." He said the plant must maintain chlorine residuals for disinfection and that high turbidity can render chlorine less effective.

Officials described a sequence of follow-up steps: build an access bypass road for heavy equipment, dredge and remove bed-load sediment, install culverts and geotextiles, deploy redundant pumps (thousands of gallons per minute capacity), and construct a cofferdam that will temporarily restore roughly 2–3 feet of head to the intake so the sedimentation basin can be used as designed. The city said those steps will be followed by a permanent engineering design and repairs to the undermined retaining wall, work that likely will be done when soils dry in summer and after required permits are secured.

The administrator said daily turbidity and coliform testing will begin immediately and that the city will supply DEQ with recent months of data to demonstrate stabilization; if test results meet expectations, crews will flush lines and request that regulators lift the boil order. Officials cautioned that lifting the boil order may be followed by a health advisory because the system is still operating on temporary measures and some groups—including dialysis patients, hospital inpatients and immunocompromised residents—could remain at elevated risk.

City staff also described the financial and logistical uncertainty around large repairs. The administrator said the city has applied for federal and state aid, is coordinating with Montana DES and has engaged the Army Corps of Engineers, which may perform or help design permanent repairs. Work to build the temporary cofferdam and supporting measures has immediate costs (the administrator estimated materials and access work), and full permanent reconstruction could cost on the order of hundreds of thousands of dollars if federal reimbursement is not approved.

Next procedural steps: the city will monitor multiple sample sites daily, provide data to DEQ, and if DEQ agrees the system is stable the city will flush lines and seek to lift the boil order; the council also scheduled a special meeting to follow dam developments and to provide further updates to the public.