Arizona’s border with Mexico is desert, wetlands, jagged mountains and cities that depend on their neighbor to the south.

It has rivers that flow north, an Indian reservation the size of Connecticut and some of the nation’s largest and most remote wilderness areas.

About 70 percent of the state’s border is known as the Tucson Sector, which includes seven mountain ranges that reach thousands of feet high.

As Tucson Sector Border Patrol Chief Paul Beeson sees it, “Two hundred sixty-two miles might not sound like a lot, but when you get out there and you see the ruggedness, the mountain ranges, the dense brush, everything that goes on with this place — it is not a place without challenges.”

Apprehensions in the sector are the lowest they’ve been since 1991, but how many get through is unknown. Increased enforcement in the urban areas pushed traffic further into the punishing desert where there’s less fencing and the terrain itself is the international barrier.

As more fencing, agents and technology made it harder to smuggle through here, the lines dividing the human and drug trafficking businesses blurred. The Sinaloa Cartel, one of the world’s most notorious drug-trafficking rings, took control.

Residents of remote areas don’t see large groups trekking through anymore, nor loaded cars flying by. Now people cross a few at a time, often dressed in camouflage and wearing carpet booties to hide their tracks.

DAILY TRAFFIC

Francine Pearl Jose lives less than five miles from the border in the Tohono O’odham Reservation, southwest of Tucson.

Her closest neighbor is four miles away. Most of the time it’s just her and her nephew, looking after their cattle.

Ever since traffic started shifting to the western corridor in the mid-1990s, she says, her property has been overrun.

Initially, she says, there were “lots of cars. It was terrible because sometimes they’d be driving really fast.” They almost ran her elderly father off the road several times.

But that stopped when three types of border fence designed to stop vehicles went in on the Tohono O’odham Nation’s 75 miles of border with Mexico.

Now she mostly sees people walking though.

“When I came this morning I saw those bottles, a guy over here and Border Patrol on their bikes picking him up,” she says, pointing to two black water jugs tied with a rope right outside her house.

“Somebody comes out almost every day. It’s just something we are kind of used to.”

In the desert, agents find gas cans, spare tires and cement bags thrown out of cars that drive back and forth across the border — filled with hundreds of pounds of trash in one direction, then replaced with people or drugs in the other.

Arizona serves as the primary distribution hub for drugs throughout the United States. While most heroin and meth is smuggled through ports of entry, marijuana tends to come through the desert. The sector is responsible for half of the marijuana seized by the Border Patrol in the Southwest.

Jose points to her 40-foot-tall water tank behind her house as a possible culprit for the traffic.

“They probably see it and are told to follow it,” she says.

She doesn’t like guns, but she’s had to arm herself. Her house was constantly getting broken into until she put metal bars on the windows and installed an iron door.

A couple of times groups of men who seem to be high on something have jumped in the back of her pickup truck, wanting a ride south.

Nothing has ever happened to her family, but violent incidents with rip crews stealing from cartels are increasing. In May in a nearby district, a man involved in a clash between smugglers and a rip crew was shot twice in the knee.

SHIFTING TRENDS

It hasn’t always been like this. In the mid-’80s to early ’90s, traffic was concentrated in places like El Paso and San Diego, where it was easy for people to cross and get on a highway.

The federal government decided to beef up enforcement in those areas and stop the flow. It worked — but at Arizona’s expense.

By the mid-’90s, Nogales agents were making more than 100,000 apprehensions a year. In the first months of fiscal 1996, agents in Douglas made 67,000 arrests — more than all the apprehensions last year in the entire Tucson Sector.

The response was to install tall pedestrian fencing near cities, where agents have minutes or seconds to catch crossers before they hop into a car or run into a house and out of sight.

As a result, smugglers fled to areas with less enforcement, and apprehensions and deaths soared in hot, desolate places like the Tohono O’odham Nation and public lands.

By 1998, the Tucson Sector was the busiest in the country.

Cars barreled through, scarring the sensitive environment. Mountains of trash piled up. Soon, thousands of agents were chasing crossers and creating new roads.

Ten years after the Secure Fence Act, which required the federal government to build up to 700 miles of border fence, 80 percent of all of Arizona’s border has some type of barrier.

Chest-high crossed steel was chosen for rural areas where loaded cars were the main concern. Cross-hatch Normandy fencing went up near rivers to allow the flow of water.

But the same terrain the government thought would deter people from attempting the journey has also made the border harder to fence and patrol. Sixty-six miles in Arizona — 50 in the Tucson Sector — have no barrier but barbed wire or mountains.

A RANCHER’S LIFE

Jim Chilton ranches 50,000 acres that include a remote stretch of the Arizona-Mexico border in the Altar Valley.

When he and his wife, Sue, are not in Washington testifying or meeting with members of Congress, they are out checking pastures and cattle. They regularly show members of the media the porous border near them.

Their house is a two-hour drive from the international line — only about 10 miles, but over steep, winding terrain and bad roads.

“I know every turn and twist,” the fifth-generation rancher says. “I’ve driven this road a thousand times.”

He drives to the spot where his ranch shares about five miles with Mexico. Less than a mile has Normandy barriers; the rest is a four-strand barbed-wire cattle fence.

“See how easy it is to get through the fence? Even a 77-year-old can do it easily,” he says as he crawls under the bent wire.

The fence stops west of the Mariposa Port of Entry, as it descends into a deep canyon. It restarts about 25 miles west near Sasabe.

There’s no cell reception here; even radio communication is spotty. A helicopter can hover above an agent and they can’t talk to each other.

Not far from here, Border Patrol agent Brian Terry was killed in 2010 in a remote canyon when his team came across a rip crew.

Chilton always carries a rifle and a shotgun.

“I have seen cartel scouts here and in that mountain over there watching us,” he says as he walks the last stretch to the border wearing boots, a cowboy hat and a black leather vest.

Ranchers around here tell of break-ins, finding marijuana bales on their property, running into druggers, as they call them — and of migrants in despair or already dead.

Chilton’s motion-activated cameras often catch small groups of men, usually heading south, sometimes armed.

“Here are the binoculars that those druggers left,” Chilton says as he climbs out of his truck. “They were watching me with them.”

Despite all the encounters, he’s never had to use his rifle. The last thing traffickers want is the added attention brought by the killing of rancher, like what happened after Robert Krentz, from neighboring Cochise County, was shot six years ago. The case remains unsolved.

As Chilton sees it, there should be more security right on the border — the Border Patrol puts agents both on the line and farther inland to catch crossers as they walk or wait for rides.

He says a road should run east and west along the international line, which the Border Patrol’s Beeson says the agency is working on. Beeson notes that 75 percent of arrests in the Tucson Sector are within 20 miles of the border. It would take about 22,000 agents just for the Tucson Sector if they were all stationed right at the border, he says.

Chilton would like to see a wall to make it harder for drug mules to haul their loads, but he knows that alone won’t solve the problem.

His neighbor, Lyle Robinson, a rancher and local veterinarian, says he wants at least the vehicle barrier the Tohono O’odham Reservation has.

“When they go from the border through my property, they cut four fences of mine,” he says. “I want a good fence that keeps our cattle in.”

Both ranchers want a forward-operating base, where agents sleep and work for days at a time right by the border. Chilton even proposed leasing the Border Patrol 10 acres for $1 a year.

The sector has four bases, and that’s all it needs for now, Beeson says. Besides, the lack of roads and infrastructure in that area doesn’t lend itself to a base.

The ranchers also want more technology at the border. There are several fixed cameras around the area, including one on Ruby Road not far from Chilton’s house, but all around are ridges and washes with thick vegetation.

“Look around you,” Chilton says. “Can they tell there’s anyone moving through that path? The cartels know exactly where to walk so the camera won’t see them.”

Beyond all that, ranchers say they want a guest-worker program that lets migrants cross the line to work, then head back home.

VIEW FROM ABOVE

Above mountain ranges and vast, flat expanses, helicopters and unmanned aircraft work best.

“From up here I can see everything,” Michael Montgomery, an operations supervisor in the Tucson branch of Customs and Border Protection’s Air and Marine Operations, says as he flies over the reservation.

Earlier this summer, a helicopter spotted 10 men believed to be drug smugglers hiding on the side of a mountain in the western part of Organ Pipe Cactus National Monument. Without the helicopter, it would have taken hours for agents to trek up there.

Organ Pipe has towers, dozens of Border Patrol trucks and a forward-operating base close to the border, but the stretch between it and Cabeza Prieta Wildlife Refuge is one of the country’s most desolate.

Not far from here, 14 migrants were found dead in May 2001 on a day when the desert sands reached 130 degrees. They were 25 miles from the border; the nearest highway was 50 miles from where a smuggler abandoned them.

Last year, 15 bodies were found in Cabeza, also covered by the Yuma Sector, refuge manager Sid Slone says.

In some areas the border is only about a mile away, but as soon as you get out of the car and start walking, everything looks the same. There is no such thing as a quick walk as you sink knee-deep into the sand every few steps.

The climate is also deceptively ruthless. A cool breeze and some cloud cover quickly give way to sweltering heat.

One day in June, as triple-digit temperatures break records, all Customs and Border Protection branches — the Border Patrol, the Office of Field Operations, and Air and Marine Operations — work together to handle nearly a dozen 911 calls from people wanting to surrender and get help. Most come from the area north of Cabeza and Organ Pipe.

By that point, migrants have walked about 60 miles, just in the U.S. They often run out of food and water, unable to carry enough for the multi-day journey.

Nearly 2,500 remains of humans have been found in Southern Arizona since 2001.

STOPPING CARS

The success and status of the border fence may be up for debate, but most people here declare that vehicle barriers work.

“Some look at the vehicle barrier and say that’s not a fence,” Border Patrol sector chief Beeson says. “But what was the threat it was seeking to address? That was vehicles.”

In 2007, the sector had 1,300 vehicles drive through the fence. That dropped to 58 last year.

It was a compromise, many say — a balance between border enforcement, the environment and tradition.

“We are starting to understand each other better,” Beeson says.

When the fence first went up in the San Bernardino National Wildlife Refuge in Cochise County, contractors bulldozed a staging area when they had said they wouldn’t. They destroyed archaeological sites and installed a culvert in a stream channel with no regard for endangered species, a 2008 Department of Interior report said.

Now the Border Patrol has its own gate to make rounds inside the refuge.

“The idea is that if we can communicate with each other, we will come up with solutions that benefit everybody,” says Bill Radke, the refuge’s manager.

The refuge supported the idea of vehicle barriers along its three miles of border. “If there was no Border Patrol presence, this area really would be pounded,” Radke says.

Organ Pipe is often touted as an example of what happens when agencies work together.

In 2014, for the first time in more than a decade, visitors to Organ Pipe Cactus National Monument were able use the 330,000 acres that make up one of the most biologically diverse protected areas in the region. Portions of the park were closed after a ranger was killed in 2002 by a man fleeing Mexican police.

In 2001, the park seized 14,000 pounds of marijuana, up from fewer than 1,000 pounds in 1997.

Part of the solution was a nearly $40 million project to build 30 miles of 3-foot-high vehicle barriers and five miles of a 15-foot-tall pedestrian fence. Staffing at the park and the nearby Border Patrol station also increased. And now there are sensors, mobile surveillance trucks and fixed camera towers.

Although traffic gets through, that pretty much stopped the loaded cars and there have been no incidents involving visitors.

There are still complaints. Agents speed, they create new roads, they don’t fully understand the sensitive areas where they work.

As a result, some ranchers restricted agents’ access to their private lands. At John Ladd’s 16,000-acre ranch in the Naco area, which shares 10 miles of border with Mexico, agents can use 37 miles of road, but over the years that has created a lot of damage, Ladd says.

“I spend half of my time checking to make sure the fence hasn’t been cut and the cattle is where it needs to be,” he says. Challenges come from both the Border Patrol and illegal traffic.

But things are getting better, he says. The agency is telling agents to watch their speed and is working on improving the complaint process, Beeson says. Liaisons work with ranchers, public land managers and the community at large.

SOME STILL GET THROUGH

The fence hasn’t stopped people from going under, over or through it. In fiscal 2010 alone, the government spent more than $7 million to repair about 4,000 breaches to the fence.

Smugglers have also gotten creative, using catapults to launch marijuana packs across the border, flying drugs over in ultralight aircrafts and drones, molding bundles into footballs or long tubes that can slip between the 4-inch slats of the fence. They’ve even zip-lined marijuana across the border using the lighting system at a baseball field in Douglas.

Within three days after the Normandy-type barrier went up in the San Bernardino Wildlife Refuge, drug smugglers began cutting off portions and lifting them to let loaded cars through, using a new system of all-weather roads constructed by the Department of Homeland Security.

Tucson Sector Border Patrol agents have found more than 115 tunnels since the first one was discovered in 1990 in Douglas — 110 in the Nogales area alone.

And a recent video of two young men climbing the 20-foot-high fence in Nogales within seconds while a TV crew recorded it was a reminder of how easily it can be done.

“We have all of it. We have cameras, sensors, radars, we have a road,” rancher Ladd says. “But until the Border Patrol is allowed to patrol the border, it’s going to be the same problem.”

The agency is spending $45 million to replace 7.5 miles of old landing-mat fencing in the Naco area, where smugglers regularly pass.

Mother Nature also poses a challenge. In 2014, part of a steel fence in Nogales was knocked down by debris after a heavy rainstorm. The cost to clean up and repair the 60 feet of rebar-reinforced fencing was $730,000, The Associated Press reported.

Shortly after the pedestrian fence was built at Organ Pipe near Lukeville, a summer storm dumped up to 2 inches of rain. The 15-foot-tall wire-mesh panels had drainage crossing with gates, but it still flooded and damaged a nearby store, a government office and private property on both sides.

Again in 2011, the gates were not raised and a 40-foot stretch of mesh fencing was knocked over by rainwater rushing through a wash. The gates were part of a $24 million drainage improvement project along the U.S.-Mexico border in 2010.

Thinking a wall can overcome all that is just not realistic, say even some people who think the border is too open. “You can’t build a wall and not patrol it,” says Ladd, who supports Donald Trump. “The misconception, from my opinion, is that the wall is a stand-all answer to everything.”

Contact the reporter at perla.trevizo@gmail.com.