California has been under a state of emergency since January because of dangerous drought conditions that currently affect over 99 per cent of the population and more than 37 million people.
Despite the fact that California has long been vulnerable to forest fires and water shortages, some suggest that a steady increase in cannabis grows since medical marijuana was legalized in the state in 1996 has had a significant impact on conditions. This has led to environmental crimes including water theft.
Scott Bauer of the California Department of Fish and Wildlife examined aerial photographs of four watersheds in northern California's so-called Emerald Triangle, which contains the counties of Mendocino, Humboldt, and Trinity. He found that marijuana growing areas doubled between 2009 and 2012.
In Humboldt alone, occasionally called the Silicon Valley of weed, there are around 4,000 commercial growers who generate at least $400 million in annual sales.
Bauer has data that shows that growers are using more than 156,000 gallons from a single tributary of the Eel River, in Mendocino County, every day - constructing dams, piping systems, and diverting water from public lands.
California's water rules are the same for any crop growers, including marijuana cultivators. By law, growers should divert no more than 10 per cent of a stream's flow and cease diversions completely in late summer when low water levels already endanger fish populations.
"We've seen streams gone dry that have never gone dry before, streams that harbor endangered fish species like steelhead trout," Bauer told VICE News. "I don't think anyone is blaming marijuana cultivators for the general drought in California but in the north, in the Emerald Triangle, there has definitely been an effect."
Cannabis is a relatively water-intensive crop to grow. The average marijuana plant needs between six and 10 gallons of water a day - in comparison with another of the state's major crops, a head of lettuce, which requires only 3.5 gallons each.
Hezekiah Allen, director of public affairs for the Emerald Growers Association, argues that the water demands of cannabis farming are exaggerated, and with clever recycling and good storage systems growers can be no additional drain on the region's resources.
"We assert that the state's demand for medical (and all) cannabis can be met using all stored rainwater," Allen told VICE News. "But it will take creative and courageous political action to develop a system of regulation that can enable this."
Allen argues that so far that political action has been missing. He added that some growers are afraid of state legislation because it might draw unwanted attention from federal authorities. According to Bauer, however, California's problem is not with weed but water.
"We're not regulating the crop," Bauer clarified. "It doesn't matter if it's tomatoes, avocados, or marijuana. We're regulating water use."
Not all growers engage in illegal water diversion or irresponsible practices such as allowing fertilizers and other chemicals to leak into the soil.
Bauer said there are three types of pot growers in California: those who move to live here, those who are from the state and have been growing for decades, and those who come just to get rich quick.
About a quarter of California's growers have come from between 200 and 5,000 miles away, "from Hawaii to Nebraska," said the government worker. There is a reason the phrase "green rush" has caught on. Bauer believes that those types of farmers are primarily to blame.
"These people are from out of town, they don't know our issues. They don't know there is not enough water, they don't know not to use fertilizers and how not to put them in the stream. They really don't see the need to protect the resources that Californians care about," Bauer continued.
Allen agrees there is a split between the types of cultivators operating in California and their concern for the environment.
"Some growers are drying entire streams with no thought for anything but their bottom line. Others are very responsible and great stewards of land and water. The problem is that the situation has largely been painted with broad strokes and all growers are treated the same," he said.
But the environmental consultant is also keen not to generalize about growers: "I've tried to resist the blame-the-outsider narrative. But it's true that we need to prevent diversion to out-of-state markets and keep all of the consuming in California to better regulate how much water is needed."
With more states set to legalize marijuana it is unclear whether increased demand or the increased ability to cultivate in other states will alleviate or exacerbate the issue.
Government workers, environmentalists, legislators, and pot growers alike are looking for solutions so that marijuana can continue to grow successfully in California without negatively impacting on the environment.
Suggested solutions include the use of rain water in the summer dry months and cracking down on out-of-state "tourist" growers, to moving grows inside and regulating farms not by number of plants but according to square foot capacity.
In July Bauer and his team were granted administrative power to fine marijuana growers up to $8,000 per day for water theft. They have also developed a new watershed enforcement team to regulate water diversions.
"We will be using that administrative action to hopefully stem the tide of water theft, which is a public resource issue and always has been," said Bauer.
For now, the crisis has created another marijuana-related entrepreneur - those who have moved into the water sales industry to supply growers, legally or illegally.
"People are taking it from towns and pumping it from neighbors' houses," said Bauer. "Anecdotally I heard that some 30 water trucks were built just to deliver to the growers."
Some have switched jobs within the industry. "People shut down their grow operations, bought water trucks and have changed from growing to supplying water to the other growers," Chip Perry, a consultant for medical marijuana company MC2, told NBC News.
With thousands of grows to check up on and a high market demand for Californian weed, Bauer is not optimistic about progress on water theft.
"It's hard to be hopeful right now just from what we see on the ground and what we see from the mapping," said Bauer. "The marijuana industry just continues to grow and grow. There are more and more people, and more and more resources used, in particular water."
Follow Olivia Crellin on Twitter: @OliviaCrellin
_Image via _Flickr