Streams in Northern California's prime marijuana-growing watersheds likely will be sucked dry this year if pot cultivation isn't curtailed, experts say.
"Essentially, marijuana can consume all the water. Every bit of it," said state Fish and Wildlife Senior Environmental Scientist Scott Bauer, who specializes in salmon recovery and is working on a study of the issue.
The findings, expected to be released soon, shed new light on a massive, largely unregulated industry in California that has been blamed for polluting streams and forests with pesticides and trash and for bulldozing trees and earth to make clearings for gardens.
A sharp increase in water-intensive pot cultivation, exacerbated by drought conditions, adds to the habitat degradation and threatens to undo decades of costly fish restoration efforts, Bauer said.
"The destruction of habitat is actually quite staggering," said Patrick Foy, a spokesman with the state Department of Fish and Wildlife.
Last year, 24 North Coast salmon-bearing tributaries were reported to have gone dry, Bauer said, though not all were verified by the agency.
Even without drought, there isn't going to be enough water to meet the pot industry's growing demand, Bauer said.
Just the illegal marijuana plants confiscated in California by law enforcement in recent years — between 2 million and 4 million annually — use upward of 1.8 billion gallons — or about 600,000 water tanker trucks over their five-month growing season, based on the average water usage documented in the study.
That amount is enough to stanch the seasonal flow of many small creeks in the region, potentially stranding the young salmon and steelhead that decades of taxpayer-funded efforts have sought to restore.
"It's really an important issue for fish," Bauer said. "We've invested a lot of money in these salmon and steelhead stock."
The North Coast sits at the center of the escalating environmental crisis. Its remote forests and seemingly ample water supplies have long made the region famed territory for West Coast pot cultivation, earning three counties — Mendocino, Humboldt and Trinity — the much-trumpeted "Emerald Triangle" moniker.
That notoriety is now marked, however, by the signs of widespread environmental degradation, endangering the region's clear, free-running streams and the wildlife that depends on them.
"I think it's really important that this industry, which has brought so much wealth to our communities and the region, take responsibility for its impacts," said Scott Greacen, executive director of Friends of the Eel River.
The state study Bauer led examined three watersheds in Humboldt County and one in Mendocino County, all of them renowned for marijuana cultivation. They include two near Redway, one near Orick and one that includes Willits.
The Redwood Creek watershed near Orick drains into the ocean. The other three watersheds feed the Eel River.
Using satellite images, researchers determined that an average of 30,000 plants were growing in each of the four watersheds in 2012, an increase since 2009 of 75 percent to 100 percent, Bauer said.
"We were able to count every plant and measure every greenhouse," Bauer said. The pot gardens they found ranged in size from 10 plants to hundreds, he said.
The greenhouse-plant counts are estimates, based on the size of the structures.
Researchers estimate each plant consumes 6 gallons of water a day. At that rate, the plants were siphoning off 180,000 gallons of water per day in each watershed — altogether more than 160 Olympic-sized swimming pools over the average 150-day growing cycle for outdoor plants.