At the checkpoints: A million pounds of pot

At the Yuma port of entry, a line of traffic going north, most with Sonora plates, backs up at the Sentri lane for “trusted travelers” who’ve passed a security check. Customs officers are searching an SUV. They soon find tightly wrapped bundles of heroin in the wheel wells, and arrest the young, well-dressed woman driving it, cuffing her hands behind her back and taking her 4-year-old daughter into custody.

Even as the number of migrants detained annually in Arizona has dropped by 70 percent over the past five years, to about 126,500, according to CBP, drug seizures have climbed.

Legal ports of entry are where most heroin, cocaine and methamphetamine seizures are made, CBP officers say. In one week in mid-March, CBP officers made five seizures at Arizona ports of entry totaling 148 pounds of cocaine, 90 pounds of methamphetamine and 9 pounds of heroin. But, by volume, marijuana dwarfs everything else. One day in mid-March, Nogales CBP officers seized a 1-ton shipment of pot in a tractortrailer of bell peppers; the next day, they arrested another tractor-trailer driver with 6,219 pounds of marijuana in boxes labeled as vacuum pumps and lamp holders.

The Tucson Sector is the main marijuana corridor from Mexico, accounting for 44 percent of all Border Patrol marijuana seizures across the entire Southwest border last fiscal year. Border Patrol agents in the Tucson Sector seized more than 1 million pounds of pot, down slightly from a year earlier but still up 14 percent from a then-record 890,000 pounds seized in 2007, according to CBP.

Most commonly, that marijuana is hauled across in remote areas by teams of backpackers, agents say. Tracking them remains a challenge. The drones (10 of which have cost $240 million to buy and operate