The California National Guard on Monday joined more than a dozen other agencies to help the Yurok tribe combat rampant marijuana grows that have threatened the reservation’s water supply, harmed its salmon and interfered with cultural ceremonies..

Law enforcement officers began serving search warrants at about 9 a.m. in the operation, which came at the request of Yurok officials and targeted properties in and near the reservation along the Klamath River.

The Humboldt County Sheriff’s Drug Enforcement Unit coordinated the raid and was joined by, among others, the Bureau of Indian Affairs, Bureau of Land Management, California Department of Justice’ North State Marijuana Investigation Team, and Yurok police.

State environmental scientists were standing by to enter the properties and survey for damage once the sites were secured.

Yurok Tribal Chairman Thomas O’Rourke joined officers as they staged at a hillside fire station Monday morning and thanked them for assisting in what was dubbed “Operation Yurok.”

“They’re stealing millions and millions of gallons of water and and it’s impacting our ecosystem,” he told the officers. “We can’t no longer make it into our dance places, our women and children can’t leave the road to gather. We can’t hunt. We can’t live the life we’ve lived for thousands of years.”

Yurok Interim Public Safety Chief Leonard Masten said tens of thousands of plants are likely to be eradicated over the next week and a half. They will be chipped on-site.

Though growers in the region once “brought their fertilizer in in batches in the dark,” O’Rourke said dump trucks now enter reservation land with impunity in broad daylight and use heavy equipment to carve roads on tribal land.

Bald Hills Road, a remote and winding route that connects the upper reservation to tribal headquarters in Klamath, used to be traveled almost exclusively by tribal members, O’Rourke said. Now, “it’s one in 10 that I recognize and every fifth car is an out-of-state plate.”

California’s largest tribe has sought help combating marijuana grows in the past but until now never received such a vigorous response. Then the drought hit.

The strains on dual water systems that serve 200 households and rely entirely on surface water became apparent last summer, when residents began complaining of plummeting pressure.

Tanks that were full on a Friday, Masten said, would be nearly empty by Monday.

When tribal staff surveyed the land from a U.S. Coast Guard helicopter, they were startled at the number of grows. By this summer they had tripled, Masten estimated. And when the marijuana crop was planted in late spring, community water gauges once again swung low.

This time, creeks ran dry.

“Streams I’ve seen in prior years with more severe droughts where water ran, there’s no water now,” said O’Rourke.

To strengthen its enforcement abilities, the tribal council last fall approved a new controlled substance ordinance that allow for civil forfeiture in circumstances where cultivation has harmed the environment.

(All growing on the reservation is illegal, as the Yurok tribe does not honor state medical marijuana law.)

The breakthrough came in April when governor’s office staff was discussing the drought with tribal officials. Gov. Jerry Brown, tribal officials were told, had pressed for California National Guard assistance with marijuana eradication and specifically urged the Office of the Adjutant General to assist in the Yurok operation, said Captain Pat Bagley, operations officer in charge at the scene.

He was expecting to haul out two miles of irrigation hose at one grow alone.

For the Yurok, the damage is broad. Sediment and chemical runoff have suffocated juvenile fish, and warmer, shallower water has triggered an increase in the parasite Ceratomyxa shasta, which targets salmon.

Rodentide has poisoned the Humboldt marten and weasel-like fisher, which the Yurok consider sacred. The danger of encroaching on a guarded grow site has made it unwise to gather medicine, acorns and materials for baskets, or to prepare sites for ceremonial dances.

The White Deerskin Dance – a biannual ceremony that was banned for decades along with other cultural practices – takes place this September, but Masten said access to the site for preparations is currently blocked by a grow.

“We are coming close to being prisoners in our own land,” O’Rourke said. “Everything we stand for, everything we do is impacted.”

On Saturday night, as the raid loomed, he and Masten were participating in a Brush Dance – a dance for the health and vibrancy of a child. At a village site near the mouth of the river, tribal members entered the dance pit in groups throughout the night as a medicine woman and two helpers tended to a young mother and her infant boy.

After the sunrise Sunday morning, they appeared elaborate regalia passed down for generations and imbued with the spirits of ancestors. Otter skin arrow quivers intricately adorned with woodpecker scalps. Dresses of abalone and dentillium shells. Intricately woven basket hats.

The Brush Dance is hosted by family groups and the frequency of the ceremonies has increased in recent years as the tribe reconnects with its culture, and more youth participate.

“I think this is not only a strong opportunity to take back our land but to set an example that the tribe has got a zero tolerance policy” toward cultivation, Masten said. “Whether you’re an Indian or a non-Indian, you’ve got to go.”