With every spring snowmelt or heavy summer monsoon comes the chance that radioactive particles and toxic chemicals could run down the lobed canyons that are etched into the sides of the Pajarito Plateau and outside the boundaries of Los Alamos National Laboratory.
Evidence of Cold War experiments have been detected at high levels in these stormwaters, including traces of high explosives, metals and other radioactive particles, which dispersed across multiple watersheds when scientists tested weapons components in the open air decades ago or were buried in unlined waste pits.
The lab has since embarked on various efforts to sample stormwater across its own campus, among other monitoring, remediation and infrastructure projects. And with the creation of the Buckman Direct Diversion in 2011 — which reroutes water from the Rio Grande and treats it to make it drinkable for households across the city of Santa Fe, Santa Fe County, and the community of Las Campanas — the U.S. Department of Energy agreed to pay to sample the river at this diversion point and operate an early notification system that would stop diversion during heavy storms.
The resulting memorandum of understanding, renewed on three-year cycles, acknowledged “that water quality management and monitoring are mutual priorities.”
But the provision to pay for water sampling was “the stickiest point” of negotiating the MOU’s fifth renewal, said Justin Greene, a Santa Fe County commissioner and former Buckman board chair. The negotiations began the year before, he added, but the Energy Department’s rebuff hardened in 2025, the year the MOU expired. It was also the beginning of the second Trump presidency.
With the expiration, the rolling $96,000 that once funded annual stormwater sampling by an outside contractor was officially cut off and a new MOU was signed, effective in 2026, without it.
“The new administration held fast to not being willing to pay for it,” Greene said of the back and forth. “So rather than forgo an MOU, we decided that it was in our best interest to get an MOU in place and deal with the cost of sampling on our own.”
There is no risk to the drinking water quality, according to the Buckman’s consulting attorney Kyle Harwood, and the early notification system has continuously operated, even when the MOU expired. But until it can find another source of funding, the Buckman’s three partners plan to cover the costs of sampling for the lab’s contaminants through an ongoing cost-sharing agreement.
The Buckman “has provided no evidence that the sampling under these grants affected BDD’s decisions whether, when, or how long to cease diversion,” an Energy Department spokesperson wrote to Source New Mexico by email.
The Buckman, however, says differently. While the early notification system independently works to shut off diversion for 12 hours, the plant uses water from its reserves to supply to customers. And sampling, according to Harwood, is helping to confirm whether that 12-hour shut-off period is too long or too short for the contaminants and extra sediment to have safely passed by.
“We’ve built a very, very comprehensive water treatment plant. So really anything that’s running down the Rio Grande, we can treat to drinking water standards and deliver it to the citizens of Santa Fe,” he said. “That’s our general mission. But if we can avoid bringing in dirty water, like high sediment water or water with high levels of contaminants, we avoid the cost and the uncertainty.”
Cleaning up the past
The lab is amid a massive expansion to produce plutonium bomb cores for a new generation of warheads and missiles. And like most sites in the nuclear weapons complex nationwide, it faces contamination from a previous era of research and production. At Los Alamos, this has come in the form of buried waste pits across the campus; elsewhere the soil has trapped radioactive particles from the testing of weapons components.
The New Mexico Environment Department and citizen groups have long scrutinized clean-up efforts, largely because the terms of a two-decade-old consent order between the state and federal government have yet to be fully met. The state fined the lab $16 million in February for not prioritizing the cleanup of its so-called legacy waste and violating safe groundwater standards.
The federal government has also deferred its remediation of a dump site called Material Disposal Area C, citing its proximity to “active facility operations.” The dump resides across the street from the plutonium handling facility, where work is taking place round the clock.
That facility — officially known as PF-4 — is the linchpin in the nation’s modernization of its nuclear arsenal, which is estimated to cost about $1.7 trillion over the next three decades, or about two Manhattan Projects per year. Los Alamos’ budget for 2026 is expected to be around $5.2 billion, much of it for weapons production. Its clean-up budget, meanwhile, is around $281 million.
“There’s no reason in hell we should’ve lost that $96,000,” said Anna Hansen, a former county commissioner and Buckman board chair. “It’s a drop in the bucket.”
A $96,000 sticking point
Planning for the Buckman Direct Diversion began in 2002 when the groundwater aquifer began showing signs of depletion. The river was seen as a kind of salvo, yet the project initially faced opposition because of the lab’s contamination of surface waters, including the Rio Grande. To assuage those fears, the Buckman’s board requested in 2007 that the Energy Department tackle a series of projects, including building barriers to keep contaminants from traveling downhill, monitoring ground and surface water, implementing an early notification system and monitoring “LANL-origin contaminants diverted with BDD raw water supplies.”
Around the same time, the National Academy of Sciences published a report that described stormwater and snowmelt as the “dominant transport mechanisms for contaminants.”
But, the National Nuclear Security Administration, which was created to oversee the health of the nation’s nuclear stockpile only years before, wouldn’t commit to an MOU. The New Mexico Legislature passed a memorial urging that the federal government “ensure the safety of Santa Fe’s drinking water.” The state’s Water Quality Control Commission also adopted monitoring criteria for the Rio Grande Basin in response to concerns of the lab’s discharges of certain radioactive contaminants in the section of the river between the Cochiti Reservoir and the San Ildefonso Pueblo.
The effort took three years, but in 2010 the first agreement was signed. A year after that, the Buckman began delivering water to the Santa Fe area.
At first, the lab conducted the sampling itself. Then, the federal government reimbursed the Buckman through a grant. The goal of sampling has been to get a snapshot of how the Rio Grande’s water quality changes during storms, says Harwood, the lawyer. This is especially the case when floods course through the normally dry arroyos in Pueblo and Los Alamos Canyons, which converge at the edge of the lab’s property and ultimately empty into the Rio Grande, three miles above the Buckman intake.
In recent decades, monsoon seasons have become more erratic and intense. At the same time, the 2000 Cerro Grande Fire and 2011 Las Conchas Fire, which burned through the forest canopy and groundcover, have led to more runoff. And as storm water and river water mix, the hydrology and chemistry becomes even more complex, potentially changing how contamination moves through the landscape with each and every storm.
The $96,000 amount was intended to cover the costs of sampling between three and four of these storms a year. Over more than a decade of doing so has shown just how unpredictable those events can be.
Samples are typically taken of baseflows, for comparisons, and throughout a storm. They show the turbidity of the water and amount of sediment carried in runoff, as well as the various contaminants that make their way into the river.
As part of its consent order with the State of New Mexico, the Energy Department collects stormwater samples in the canyons above the Rio Grande and has installed gabion baskets and other erosion control measures to prevent the movement of contaminants. The New Mexico Environment Department has no jurisdiction over the agreement, a spokesperson said, but the agency’s Surface Water Quality Bureau does collect “samples from the Middle Rio Grande watershed — including upstream and downstream of the BDD intake,” he added. However, only the Environmental Protection Agency has authority to enforce violations under a stormwater discharge permit, which is intended to regulate — and reduce — runoff from old waste sites.
A handful of stormwater samples have shown high readings. One 2024 sample, counting the total amount of all alpha emitting radioactive particles in stormwater in Pueblo Canyon, was 50 times higher than the state and federal standards for surface waters. At times, aluminum has been detected at thousands of times higher than standards; lead has been detected hundreds of times higher.
Most of the samples collected at the intake where water is diverted from the Rio Grande for the Buckman show low or even undetectable levels of contaminants during both baseflow and storm events. But there are notable spikes there, too. In 2025, for instance, the total amount of all alpha emitting radioactive particles in stormwater was 55 times higher than state and federal standards for surface waters.
But, exceeding a target action level, as it’s called, doesn’t necessarily lead to a violation, an EPA spokesperson explained by email. “It tells you that current controls may not be adequate, so you must evaluate, improve controls, and then re-sample to confirm their authenticity.”
In 2025, the New Mexico State Legislature voted to create a state-level surface water permitting program, which is still in progress.
Among its powers would be to deny permits that “contribute to water contaminant levels in excess of downstream state or tribal water quality standards.”