State finalizes monitoring plan, compels Knife River groundwater investigation; county domestic-well testing continues

PRINEVILLE, Ore. — The Oregon Department of Environmental Quality told Crook County residents April 23 that a comprehensive plan to identify the source of local groundwater contamination is finished but lacks funding, that the state has funded two rounds of domestic-well testing at 61 homes, and that DEQ and the state geology agency compelled Knife River to carry out a site-specific groundwater investigation in October 2024.

DEQ regional liaison Greg Sweetland told a packed public meeting that the agency finalized a comprehensive sampling and analysis plan (SAP) intended to determine whether a specific source is responsible for contamination in groundwater near Northwest Elliott Lane and Northwest Stahansick Lane. "The plan is completed. We worked with EPA on that," Sweetland said, and added the plan would cost about $1.5 million and so far has not been funded.

The lack of that funding prompted DEQ to seek other steps. The legislature provided money for a separate domestic-well testing program: DEQ sampled 61 private wells last fall and has a second round beginning the week after the April 23 meeting. Sweetland said the domestic tests focus first on health risks; results and quality‑assured data go both to residents and to the Oregon Health Authority, which will prepare a letter of health consultation once the second round is processed.

DEQ also described a parallel, enforceable step taken in October 2024. Under language in the WPCF (water pollution control facility) general permit, DEQ and the Oregon Department of Geology and Mineral Industries (DOGAMI) notified Knife River that the agencies had a "suspicion of groundwater contamination on your property, and we are going to compel a groundwater investigation." That compelled investigation has been the subject of technical review and revisions between Knife River and state and federal reviewers; Sweetland said the agencies are close to finalizing a work plan that will require monthly and quarterly monitoring and soil samples, including samples from wash pits and settling ponds.

The plan calls for roughly 19–20 monitoring wells on and around the Knife River footprint, Sweetland said, and includes soil sampling in specific locations such as wash pits and settling ponds. To address community trust concerns about company-collected samples, the state will collect secondary samples during Knife River sampling events; those secondary samples will be analyzed by either DEQ, EPA or an independent analyst so that there are paired, independently collected measurements.

Sweetland also told the meeting that Knife River temporarily stopped using a wash pit on March 11, 2025. He said the stoppage gives investigators an opportunity to collect data both while operations are inactive and, if the company later resumes, while operations are active — a contrast that may help identify operational impacts on groundwater. "There is nothing preventing the state from requiring more monitoring once they restart," Sweetland said.

On water-quality results from the domestic program, Sweetland said 61 wells were sampled for about two dozen parameters; the transcript of the meeting reports that 11 wells tested above the maximum contaminant level for nitrate and that a subset also showed E. coli. The Oregon Health Authority will evaluate collective health risk across the sampled homes after quality-assurance steps are complete.

Sweetland described the state’s enforcement toolbox: DEQ can document violations, refer cases to the Oregon Department of Justice, and seek civil penalties under statutory formulas; however, he noted penalties assessed to companies go to the state's general fund and are not available for DEQ use. He said a stop-work order is a legal option but is "extremely rare".

Residents and county officials pressed technical and timeline questions during more than two hours of public comment. Topics included whether soils and settling ponds would be sampled (they will), the potential need for off‑property monitoring wells (the work plan includes some off‑property sites and DEQ said it will seek landowner permission), and how the state will notify residents if a health risk is confirmed (DEQ said it is coordinating with Crook County Public Health and Oregon Health Authority and that OHA’s consultation process includes community outreach).

The county commissioners convened the April 23 special meeting in the Bridal Room of the county library to hear the state briefing and receive public questions; after the DEQ presentation and public comment the board adjourned the meeting.

The state’s next steps described at the meeting: finalize the Knife River groundwater-investigation work plan within weeks, begin monitoring and paired state-secondary sampling immediately after implementation, complete the second round of domestic-well sampling and transmit data to Oregon Health Authority for a health consultation, and continue interagency coordination with EPA, DOGAMI and local officials. The comprehensive basin-scale SAP — the $1.5 million plan intended to answer source questions across a larger area — remains complete but unfunded.

If finalized, the Knife River work plan will be published and DEQ said it intends to post investigation documents and data (including the domestic-well results and the SAP) on a public web location and make maps and work plans available to residents and local officials.