Speed Reads

Pot politics

Scientists say California medical pot farms are draining streams

Uriel Sinai/Getty Images

Here's another topic of discussion for the "to legalize or not to legalize" debate.

Biologists in Northern California say medical marijuana farms are guzzling up water from adjacent streams and rivers, The Associated Press reports. Using Google's satellite map imagery, scientists were able to identify where exactly the pot gardens are located in relation to nearby river systems; they found that nearly 30,000 plants are being grown in each of four affected watersheds. While the study's authors say each plant uses about six gallons of water per day over a 150-day growing season, some of the farmers claim those estimates are way too high.

Still, biologists first noted the streams running dry more often 18 years ago — the same time California passed Proposition 215, which legalized the use of marijuana for medicinal purposes.

"We knew people were diverting water for marijuana operations, but we wanted to know exactly how much," says Scott Bauer, a department biologist studying the effects. "We didn't know they could consume all the water in a stream."