After hiking two miles over rough terrain Wednesday morning, a law enforcement team found 10,000 marijuana plants deep inside Henry Coe State Park near Gilroy — one of the largest hauls in recent years.

The Santa Clara County Sheriff’s Office Marijuana Eradication team, accompanied by its SWAT team and state Fish and Wildlife wardens, discovered the pot plants growing in a canyon in the southeastern part of the park.

The sheriff’s office anticipated a garden of about 6,000 plants, according to Sgt. John Spagnola, who heads the team. Officers also seized two .22-caliber pellet rifles with high-powered scopes from the garden, which was most likely operated by a Mexican cartel, according to Sheriff Laurie Smith.

“These are hugely dangerous operations,” said Smith, who monitored the eradication effort from a command post within the park. “It’s one of the most dangerous things that we do. We haven’t found a grow ever that didn’t have evidence of firearms.”

Since 2006, the sheriff’s office has been involved in four officer-involved shootings during the eradication of marijuana gardens on public lands. In 2005, there was a deadly shootout between marijuana growers and law enforcement in the hills above Los Gatos. One of the men guarding the garden was shot and killed, and a state fish and wildlife warden was shot in the leg.

At a site last year near Uvas Canyon County Park, deputies seized an AK-47, a 9-mm Glock, body armor and bags of ammunition, Spagnola said. The armed men guarding the marijuana had also set up camp in a “military” fashion, allowing them to fire upon anyone making their way into the garden.

The sheriff’s office sent in its SWAT team Wednesday because they believe the marijuana plants were being guarded by armed men.

The marijuana garden was first located by the sheriff’s office in early June, the same site of an illegal growing operation last summer. Later in the month, someone stumbled across a pond located on a ridge above the garden with irrigation piping running down the mountain. As the person looked in the canyon through binoculars, he heard the sound of a rifle being fired, perhaps in his direction, Spagnola said.

The people operating the garden were stealing water from the pond, located on private property next to the park, to irrigate the massive garden.

Mark Michilizzi, a warden with the state Department of Fish and Wildlife, said the average marijuana plant consumes about five gallons of water per day, and often times the growers dump fertilizers and pesticides straight into the water source. Illegal growers also pollute and dam creeks and streams to water the marijuana plants.

“A lot of people don’t realize the extent of the environmental damage that occurs as a result of these marijuana grows, everything from illegal pesticides to fertilizers to large amounts of garbage,” Michilizzi said. “It’s a very serious problem.”

Wednesday’s effort was part of the annual fight against large marijuana growing operations that pop up every spring and summer in remote areas of Santa Clara County.

In the past two years, the eradications teams cut down more than 261,000 marijuana plants, arrested 51 people on a variety of drug, weapons and environmental charges, and seized about two dozen weapons, including assault rifles.

So far this year the sheriff’s office has made 19 arrests, Smith said. As of last week, the state Department of Fish and Wildlife had eradicated approximately 150,000 marijuana plants, Michilizzi said.

“The illegal cultivation of marijuana on public lands is something that happens all over California,” Michilizzi said.

The armed men who guard the marijuana gardens are often brought in from Los Angeles, Bakersfield, Modesto and Merced, Spagnola said. The sheriff’s office took fingerprints at a site last summer and came up with a suspect out of Los Angeles.

“A lot of them are field workers,” Spagnola said. “They get paid more money to harvest marijuana than almonds. They are paid more by the cartel.”

The California Highway Patrol also assisted in Wednesday’s operation, sending one of its helicopters to help haul the marijuana out of the park. The command post was located about seven miles off Highway 152 just past Casa de Fruta on the outskirts of Santa Clara County. From there, the marijuana garden was a few more miles inside the park.

“The people we are catching are not the people that are profiting,” Smith said. “We’d like to find the people that are profiting. Then we’re hoping we don’t come back next year.”

Contact Mark Gomez at 408-920-5869. Follow him at Twitter.com/MarkMgomez.