Hot droughts + Truckee River discharges
And Colorado River negotiations continue.
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Study: Climate change key driver of drought in the Western U.S.
Higher temperatures are now a primary force shaping the size and intensity of drought in the Western U.S., according to a paper published in Science Advances.
Precipitation has long been the main driver of Western U.S. droughts. But that’s changed with rising temperatures and a thirstier atmosphere. Evaporative demand, the paper noted, accounted for 61% of the severity of the 2020-2022 drought in the Western U.S., whereas deficit from lack of precipitation accounted for about 39%.
“Research has already shown that warmer temperatures contribute to drought, but this is, to our knowledge, the first study that actually shows that moisture loss due to demand is greater than the moisture loss due to lack of rainfall,” Rong Fu, a UCLA professor of atmospheric science and an author on the paper, said with its release.
More coverage of the study from the L.A Times’ Ian James:
The scientists said their findings, which add to a growing body of research documenting climate change’s role in worsening droughts, underscore an urgent need to reduce planet-warming emissions while also changing water management and drought strategies to adapt to the new reality of heat-driven dry spells.
Nevada investigating Truckee River sewage discharges
Nevada environmental regulators are investigating how raw sewage was discharged into the Truckee River, as KNVR’s Joe Hart reported last week. The sewage spills into the river occurred after a new apartment complex in the city of Sparks attached its sewer line to the storm drain, which discharges into the river without treatment.
As Hart reported, the unpermitted discharges — discovered after a citizen complaint — were not reported to the state as required by law. Although the faulty connection was reportedly fixed in October 2023, neither the city nor the developer disclosed the discharges to the state, raising important accountability questions. The state has not released an estimated volume of sewage released, but based on when the storm drain connection was made (in 2022) and the average daily usage (165 gallons per day), Hart estimated that about 2 million gallons of raw sewage could have ended up in the river.
As he notes, it could be more or less.
The bigger picture: The Truckee River flows from Lake Tahoe to its terminus at Pyramid Lake. Like many Great Basin lakes, Pyramid Lake has no outlet to the sea. The water that flows to the lake stays there. That means both water quality and water quantity have played a critical role in managing the Truckee River and recovering endemic fish species like the Lahontan cutthroat trout and cui-ui.
A spokesperson for the Division of Environmental Protection said the agency is still investigating and evaluating the consequences of the raw sewage releases, but added in a statement that “when there are discharges of raw sewage to the environment, it degrades water quality and exposes humans to pathogens and viruses that can cause serious illness. Raw sewage may also pollute our waterways, adversely affecting fish and other wildlife species and impacting drinking water sources.”
Penalties could run as much as $25,000/day of noncompliance, could include expenses for corrective actions and compensation for the loss of wildlife or aquatic species.
On the Colorado River, the “deadline’s the deadline”
There seems to be consensus among Colorado River negotiators that the election of Donald Trump to a second term will not change the trajectory of talks over how to manage the over-allocated and overused river in an increasingly arid future.
As the Colorado Sun’s Shannon Mullane reports, it’s actually one of the few things the negotiators seem to agree on as they work toward a new set of guidelines to replace current rules set to expire in 2026. Through the Bureau of Reclamation, the federal government plays a key role in the Colorado River, especially for the three U.S states that draw from Lake Mead: Arizona, California and Nevada. That doesn’t mean there is no risk or instability, as UNR researcher Elizabeth Koebele told KUNC’s Alex Hager in a story this month: “I worry that when our house isn't in order inside the [Colorado River] basin, then these bigger, national level, ‘big-P Political’ changes are more likely to impact policy making, or more likely to add more stress to policy making.”
Meanwhile on the Columbia River…
U.S. and Canadian officials are working to finalize the Columbia River Treaty before the Trump administration takes office, The Canadian Press reported.
NASA satellites spot global freshwater declines
A team of international researchers have observed an abrupt drop in global freshwater since 2014, according to satellite data published this month in Surveys in Geophysics.
The NASA satellite data measurements indicate the average amount of freshwater on land from 2015-2023 was 290 cubic miles less than the average from 2002-2014 — or as one researcher put it, a loss roughly “two and a half times the volume of Lake Erie.”
More information from the NASA press release:
The decline in global freshwater reported in the study began with a massive drought in northern and central Brazil, and was followed shortly by a series of major droughts in Australasia, South America, North America, Europe, and Africa. Warmer ocean temperatures in the tropical Pacific from late 2014 into 2016, culminating in one of the most significant El Niño events since 1950, led to shifts in atmospheric jet streams that altered weather and rainfall patterns around the world. However, even after El Niño subsided, global freshwater failed to rebound. In fact, Rodell and team report that 13 of the world’s 30 most intense droughts observed by GRACE occurred since January 2015. Rodell and colleagues suspect that global warming might be contributing to the enduring freshwater depletion.
Here’s what else I’m watching:
A century-old practice allows people to use more than their legal share of Colorado River water. Researchers say it should stop. (Colorado Sun)
Column: Green hydrogen or greenwashing? Mojave water scheme takes new twist (L.A. Times)
UCLA evaluates L.A.’s plan to invest billions in wastewater recycling infrastructure (UCLA)
A century after Owens Valley aqueduct protest, event marks tense time in L.A. water history (L.A. Times)
Federal money will bring clean water to Nevada tribe (Las Vegas Sun)
How unconventional crops could save water — and reshape Utah farming (KUER)
California bracing for extreme rainfall. Here’s why this atmospheric river will be different (San Francisco Chronicle)
Probation hearing for Tulare County groundwater region canceled (SJV Water)
That’s it for now. More to write about soon…
Take care, and until next time,
Daniel