Water diversion at the Mattole River watershed can threaten the existence of fish and insect populations. (Times-Standard file)
PUBLISHED: | UPDATED:

The state Department of Fish and Wildlife is researching how cannabis cultivators who divert water from Mattole River streams might be impacting the river’s fish and insect populations, though the head of a restoration organization says far more than cannabis is affecting the water.

By fall 2019, the researchers will publish findings on the full environmental effects of cannabis grows. While the research is intended to “support efforts to establish” sustainable cultivation levels, the study’s main focus is analysis, said department representative Janice Mackey.

“The intention of the pilot study was to collect scientific data to determine the condition of the focus watersheds,” Mackey said in an email. “It is our hope that science will inform management decisions, and that cannabis can be cultivated in California in a sustainable manner while limiting impacts to the environment.”

Diverting water from streams for any sort of use can limit space for fish populations to rear offspring. Insect feeds are similarly jeopardized, along with overall water quality. In worst cases, the amount of oxygen dissolved in the water can drop to critical lows.

If the flows in the stream get low enough, they can break off into isolated pools, which in turn leave fish populations vulnerable to other animal predators, said Nathan Queener, executive director of the Mattole River Council.

“The fish have fewer places to go and places to hide,” Queener said.

Water levels in the Mattole River are already very low in the summer months, which to a “large extent” is the result of a “natural phenomenon,” Queener said. Diverting water from the streams in the middle of August could make things more severe.

One thing to emphasize, Queener said, is that cannabis growers are not the only diverters of Mattole River water. Nearby residents use the water for other agricultural purposes or even housekeeping.

“It’s important to recognize there are a lot of growers trying to use best practices and be good stewards,” Queener said. “I appreciate the fact that (the Department of Fish and Wildlife) is, in this study, trying to be proactive, but it’s really important to realize that there is a broad spectrum of management practices people shouldn’t use. We shouldn’t paint with too broad a brush.”

The state Water Board has already rolled out a “small irrigation use” process for cannabis growers to install storage tanks for use during the dryer months of the year. It’s part of the overall state permitting process for legal compliance.

But as the state continues to figure out the regulations, more research will guide the way.

“Research is an important tool in understanding the impacts of cannabis cultivation on the environment,” Joshua Grover, the department’s cannabis program director, said in a release.

The department supports the legal market, Grover said, and wants to work with growers to curb the environmental effects of their grows.

“Using a science-based approach will help our staff make informed management decisions on sustainable levels of cannabis cultivation,” Grover said.

Shomik Mukherjee can be reached at 707-441-0504.

blog comments powered by Disqus