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Your Weed Habit Could Be Killing Off California Salmon

Not to make you come down off the high or anything, but in Northern California—where weed operations are booming—pot cultivation is drying up the creeks and streams where Coho salmon and steelhead trout swim.
Foto via Wiki Commons

If you like to smoke weed and crave the pristine wild-caught salmon—that's a favorite on white tablecloth restaurants all over the Northwest—you might not be able to enjoy both habits in the near future. In Northern California, where grow operations have boomed since the state's 1996 decision to legalize medical marijuana, pot cultivation is drying up the creeks and streams where the state's Coho salmon and steelhead trout swim. It's also filling those bodies of water with sediment caused by erosion and runoff from chemical fertilizers.


"Last summer, people kept calling us to give us the bad news of, 'Hey, my creek's gone dry,'" said Scott Bauer, a senior environmental scientist at California's Department of Fish and Wildlife. "And they were saying, 'We think it's because of marijuana cultivation.'"

In a state that's been crippled with drought since last year, that assumption makes sense when you take a brief glance at the numbers. In Northern California's so-called "Emerald Triangle" of Humboldt, Mendocino, and Trinity counties—where people had been growing pot illegally for decades—weed cultivation has doubled in the past five years. Bauer guessed that grow sites there now number around 10,000. A single site can contain hundreds of plants, and each plant, Bauer said, needs about six gallons of water per day, with more (up to 15 gallons) needed during the late summer. When you consider how long the growing season lasts—150 days—that's a shitload of water.

But just to confirm the anecdotal evidence suggesting that an increase in pot plantations has led to dry creeks, Bauer and his team conducted a study last year in which they mapped growers in the Emerald Triangle, counted the number of individual plants per site, and had a hydrologist examine the watershed (an area's underground water source) to see how much usage the watershed could sustain. The hydrologist's conclusion was that the water needed for all those pot plants would dry up three out of four streams in the area.


And where there are dry streams, Bauer said, there's dead fish. That's a problem for California Coho salmon, whose populations have declined dramatically over the past few decades. Though Bauer's department works to promote Coho conservation, he's not sure their numbers will be able to withstand the assault of the state's pot industry.

"We're losing generations of fish," he said. "I don't know if recovery is going to be possible."

And the problem isn't limited to a lack of water: Erosion, which results when forests are cleared to make way for marijuana plants, is filling streams with dirt and runoff from the chemical fertilizers used to treat the crops has caused algae blooms in nearby bodies of water, Bauer said. Dirt and sediment in streams kill fish by smothering them; algae blooms kill them by using up too much of the water's dissolved oxygen.

The problem, Bauer said, is how little regulation California's nascent pot industry is subjected to. Because growers operate in a gray zone—their activities are permitted under state law but are illegal under federal law—it's not always clear what permits are needed to build roads, raze forests, and draw water. If this permitting process were made clearer, and more strictly enforced, then the California government would better informed of what growers were up to and could fine them for environmental abuses.

"People don't know the rules," Bauer said. "And they feel like they won't get caught."


Kristin Nevedal, the founding chairwoman of the Emerald Growers Association, an advocacy group for the area's medical marijuana growers, agreed that a lack of clear-cut rules regarding grow sites has had an environmental impact.

"There's too little education on permits," Nevedal said. "And it's catching up with us."

But she rejected the idea that dry streams and dwindling fish populations could be blamed squarely on the area's pot farmers.

"Is it strictly because of cannabis cultivation? No, it's not," she said.

For one thing, Nevedal said, weather patterns in Northern California have completely changed over the past few decades, making it hard to predict how much water will be available to farmers of all kinds in any given season.

"We used to get steady rains here," she said. "Now, it comes in these huge weather events. It's totally unpredictable.

Nevedal added that the logging industry, which for decades operated unregulated—much like cannabis today—played no small role in the erosion problems that now plague the area's waterways.

"That did a lot of damage," she said.

Like Bauer, Nevedal believes that much more regulation is needed to aid pot growers in their mission to raise a low-impact crop. Currently, she said, lingering stigmas against weed prevent it from being taken seriously as an agricultural product; when it's finally treated like one, she said, rules and regulations will be more clearly delineated and growers will have less difficulty following best practices and leaving behind a smaller footprint.

"What we need for marijuana is an agricultural-minded model," she said. "We need to acknowledge it for what it is."

So keep an eye out for the "weed" section in the upcoming Farm Bill the next time you puff, puff, pass.