While a new environmental impact statement (EIS) by three government agencies operating the lower Snake River dams opposes breaching them to aid salmon recovery, the Environmental Protection Agency has proposed new water temperature limits on both the Columbia and Snake Rivers that could impact their operations. Although intended to keep water temperatures down and protect salmon moving through the hydro dam system, historical data shows that the proposed new limits are beyond the Snake River’s peak temperatures in the years prior to the dams’ construction.
If approved, the EPA’s rule could have significant implications for future operation of the four lower Snake River dams, which combined provide seven percent of total electricity in Washington state. However, the dams can also create slack water that raises the temperatures that, if too high, can kill migrating salmon.
Last month the state Department of Ecology approved changes to the Clean Water Act requiring that both the Columbia River and lower Snake River dams comply with state water quality standards regarding water temperatures. The decision was praised by Columbia Riverkeeper, which recently released a statement that said: “the solution is clear: the dams must be removed.”
Among those opposed to the draft rule is Northwest River Partners, which serves non-profit electric utilities in Washington, Oregon, Idaho, Montana, Nevada, and Wyoming. Its public comment to EPA noted that the federal agency’s draft rule found water entering from Canada greatly exceeds Washington water quality standards. “This means that the Washington and Oregon standards cannot be met, regardless of the existence of the lower Columbia and lower Snake dams. What remains clear is that the newly proposed burden for regional hydropower operators is unrealistic, unworkable, and unfair to the communities that depend on affordable hydroelectricity to help make ends meet.”
Also opposed to breaching the dams is Washington Policy Center Environmental Director Todd Myers. In a January policy brief he wrote that “the impact of the dams on river temperature is limited and has declined significantly over the past dozen years. This does not mean the dams have no effect on temperatures, but it does indicate that spending billions of dollars to destroy the dams would likely yield only small changes in river temperatures.”
Myers told Lens that since 2003, the temperature variations between the Snake River dams have declined. Those temperature differences have also moved to earlier in the summer from , when the fall chinook runs occur. “The data shows that temperature impact is getting lower and its shifting to a less dangerous time.”
He added that one likely reason for this is improved operational management by the U.S. Army Corps of Engineers (USACE), one of the three agencies that oversees the system. USACE Northwestern Division Public Affairs Director Matt Rabe told Lens they use the Dworshak dam on the North Fork Clearwater River in Idaho to cool the water flowing into the Snake River, known as “flow augmentation.” The federal agency typically does this in the early summer as temperatures rise, concluding in the early fall.
Although USACE is still reviewing EPA’s draft rule, Rabe noted that previous studies of the Snake River’s water temperatures in the 1950s before the dams were constructed showed that they would have violated EPA’s proposed requirements.
Rabe also said that “current evaluations by EPA (and supported by Corps modeling through the Columbia River Systems Operations (CRSO) indicates that there are many factors that influence temperatures and that, on any given day in that month, the standard may be attained but attainment cannot reasonably be expected to occur every day of that month during the summer.”
If breached, as some have advocated, the energy generated by the Snake River dams would either be lost or require alternative sources to compensate. Additionally, breaching them would remove 47,926 acres of irrigated land.
The EPA is accepting public comments on its draft rule through July 31.