DOE and contractors report Rocky Flats 2025 monitoring met points‑of‑compliance standards; one upstream evaluation site briefly exceeded uranium standard

The U.S. Department of Energy Office of Legacy Management (DOE/LM) and contractor RSI presented the Rocky Flats calendar‑year 2025 annual report, saying routine monitoring showed compliance at the locations where site water leaves the property while one upstream evaluation location briefly triggered a uranium reportable condition.

In a detailed presentation, Michelle Franke, site manager for Rocky Flats, and technical leads from RSI summarized monitoring programs governed by the Rocky Flats Legacy Management Agreement (RFLMA). "We have people on site almost every day," Franke said, describing long‑term responsibilities such as groundwater and surface water monitoring, treatment system operation, inspections and public reporting.

Caleb Arts, surface water lead, described a layered monitoring approach: performance monitoring locations and points of evaluation (POEs) nearer the former industrial area, and two points of compliance (POCs) where water exits the site toward the Rocky Flats National Wildlife Refuge. Arts said the Walnut Creek and Woman Creek drainages have relatively low flows compared with nearby stream gauges and that monitoring uses flow‑paced composite sampling and grab samples.

Arts identified one POE reportable condition in 2025 at monitoring location GS‑10: the 12‑month rolling average uranium concentration exceeded the 16.8 µg/L standard on April 30, 2025. "As of May 31, 2025, the 12‑month rolling average uranium concentration came below that 16.8 standard and was calculated to be 16.4 micrograms per liter," Arts said. He emphasized that the exceedance at GS‑10 did not translate into a POC exceedance at the locations where site water leaves the property.

John Boylan, groundwater lead, summarized the groundwater monitoring network and treatment systems. He said AOC (area‑of‑concern) wells and RCRA wells are monitored per RFLMA decision rules and that no AOC reportable conditions were identified in 2025. Boylan also described treatment‑system performance: effluent from the East Trenches plume treatment system met applicable RFLMA standards, and a change to an air‑stripper treatment approach substantially reduced detected VOCs and trichloroethylene (TCE) concentrations in effluent samples.

Boylan said the Solar Ponds plume treatment system (SPPTS) treats uranium and nitrate and met the RFLMA nitrate standard in 2025; recognizing earlier uranium removal limits, the team installed a new uranium treatment component (UTC) in summer 2025 and conducted two months of performance testing, with continued optimization into 2026. He described the UTC process—co‑precipitation using alum, solids dewatering, periodic waste sampling and off‑site disposition when required—and said waste disposition had not been needed yet but is expected about once or twice per year once operations are established.

To distinguish natural uranium from Rocky Flats‑derived uranium, Boylan said the team sent samples to Lawrence Berkeley National Laboratory for isotopic analysis. Some downstream wells returned predominantly natural uranium signatures, while samples closer to source areas showed a high percentage of anthropogenic uranium (one sample was ~93% anthropogenic), supporting source attributions in those locations.

Panelists stressed that the RFLMA contains decision rules for reportable conditions. Arts described the process: data validation, a DOE notification window to agencies and the public, and a 30‑day window to submit a plan and schedule for regulator evaluation of next steps.

The presenters encouraged public review of the full annual report and slides once DOE/LM restores website access; they provided RF info contact information for follow‑up questions. The Q&A that followed addressed drought and climate impacts on sampling (more dry wells and lower flows in 2025–2026), wildfire precautions, PFAS quarterly reporting, and details about how groundwater discharges to surface water.

The meeting concluded with public comment and a reminder that the detailed annual report contains the full datasets and analyses.

The DOE/LM presentation and RSI technical leads will continue optimization of the UTC and monitor whether the GS‑10 signal reappears; the agencies will follow RFLMA decision steps if additional reportable conditions occur.