Police said public works employees hauled out an estimated 39 pounds of marijuana while investigating a clogged sewer line in Nogales, Arizona on Wednesday. Workers in the southern Arizona city, near the Mexico border, found two wet, feces-covered bales of marijuana tied to a rope feeding into the sewer system, reports Hank Stephenson at the Nogales International. The bales, tied with about 900 feet and rope, were hauled out through a manhole on Hudgins Street. The sewer line from which the pot was removed feeds into the International Outflow Interceptor (IOI) from the Heroes neighborhood in Nogales, Sonora, Mexico. A search of the Rio Rico sewer plant, where the IOI ends, "didn't turn up any more drugs," a Nogales Police Department spokesman said. Police Lt. Carlos Jiminez said it's the first time they've discovered bales of marijuana tied to a rope that they believe smugglers were trying to maneuver through the sewer line, reports The Associated Press. But it's not the first time marijuana has been found in the sewer system in Nogales. Back in 2009, several bales of pot were found clogging the IOI, according to city works employees. In February 2010, Border Patrol agents found 55 pounds of marijuana, along with a scuba tank and mask, in the storm drains that run across the U.S./Mexico border, said Border Patrol spokeswoman Colleen Agle. U.S. Border Patrol agent Colleen Agle says drug smugglers have moved literally underground to avoid detection "All of the efforts we have going along the border are changing the way smugglers are doing business," Agle said. "They can't operate the way they used to, so that's why they're looking for these different avenues ... They want to exploit this very innocent, very legitimate infrastructure to get their drugs through." The sewer pipe, about 18 inches in diameter, runs from a main point in Sonora and carries sewage downhill into Arizona, according to Nogales City Engineer Juan Guerra, confirming the old adage that "shit rolls downhill." Smugglers ostensibly just need to drop the bales of pot down a manhole on the Mexican side of the border and then have someone catch it when it comes across -- which would explain the rope tied to the bales, according to Guerra. "It would be very difficult to stop this type of transport because we would have to monitor a very big sewer system," he said. One thing's for sure: If they do assign someone to that job, it doesn't sound like a very enviable position. But you, guessed it, those intrepid Border Patrol agents are already on it. This guys are so determined to keep you from having marijuana, they're willing to get covered in excrement for their efforts. And of course, you still have pot to smoke, so you might say they're shit out of luck. Though the agency said it doesn't actually send people down into the sewers -- which would be a tight squeeze, especially for typically porcine Border Patrol agents -- it does constantly "monitor" the two main drainage tunnels that connect the underside of Ambos Nogales. Drug smugglers have increasingly turned to (literally) underground methods to get weed into the U.S., according to Agle. Tunnels are becoming more common, and the Border Patrol has teamed up with Mexican authorities to uncover the digs before they reach Arizona, she said. "It's an ever-evolving battle, and as diggers are busted, smugglers become more creative," Nogales International reports. "The traditional running it across the border or driving it across the border is just not working anymore," Agle said.