PEÑITAS, Texas — On a recent afternoon in this Rio Grande Valley town, Juan Longoria stood in his driveway, talking on his cellphone while enjoying a longneck. The only thing that blocked his view of the clear Texas sky was a tethered blimp floating thousands of feet in the air.

The blimp — which contains video and radar equipment for detecting human smugglers, illegal crossers and drug and human traffickers — was formerly used by the U.S. Department of Defense and is now controlled by the U.S. Border Patrol. It can be seen miles away by drivers on State Highway 83.

What some might consider an eyesore is a welcome addition to Longoria, who said that before the recent influx of equipment like the blimp, also called an aerostat system, he would often chase undocumented immigrants from his property.

“They were here in the back or in the front yard and they’d get here at all hours,” he said in Spanish. “They’d come here to look for people to take them north, to McAllen or wherever. Now they don’t. And I am fine with that.”

U.S. Border Patrol agents say the illegal traffic on public and private land in the Rio Grande Valley has triggered the need for additional resources in the region. In addition to the controversial border fence that straddles miles of the Rio Grande in this swampy part of Texas, the Valley has also seen an influx of watchtowers, barricades and agents. And as a new initiative hit the Valley this month, agents are optimistic that the buildup will help curb the illegal activity.

In the latest installment, more than 100 Border Patrol agents have been sent to the Rio Grande Valley from Laredo, Arizona and California, part of a Department of Homeland Security initiative called the South Texas Campaign. Officials describe the initiative, which started in 2012, as a “risk-based approach” in which resources are shifted to an area with greater need. The campaign focuses on the South Texas corridor, which includes the Laredo, Del Rio and Rio Grande Valley sectors, said Special Operations Agent Jose Castro of Customs and Border Protection.

Border Patrol officials say information gathered from apprehensions, in conjunction with operations that include the aerostat, watchtowers and increased boots on the ground, will help law enforcement target known threats who have made the Valley a breeding ground for illegal border-related activity.

“What we address is the people that operate [here], the smugglers, the stash house operators — the people that cause that, that’s more of our focus,” Border Patrol Agent David Benavides said.

The Rio Grande Valley sector, which extends from Rio Grande City to Brownsville on the border, north to Falfurrias in Brooks County and includes Corpus Christi on the coast, is in the most need of the increased assets, agents say.

While reports say the main cause of illegal traffic in the Rio Grande Valley is a result of more attention on crossing and smuggling corridors in Arizona, Benavides says such a theory is difficult to prove.

“The influx here is mainly Central Americans, and that’s different from what they had in Arizona,” he said. There, he added, the illegal entrants were predominantly from Mexico.

Analysts have said Central America’s younger workforce, combined with increased violence and instability in the region, is luring migrants to take the often dangerous trek through Mexico to reach U.S. soil.

In fiscal year 2013, the Big Bend sector was the only one of the five Texas areas with a decrease in apprehensions of immigrants attempting to cross into Texas illegally compared with 2012, from 3,965 to 3,684. (The federal government’s fiscal year runs from October to September.) In the Rio Grande Valley sector, formerly known as the McAllen sector, the apprehension total exploded from 97,762 in 2012 to 154,453 in 2013, the highest figure since 1999.

Since October, agents have apprehended more than 100,000 undocumented immigrants in the Valley sector, Border Patrol spokesman Daniel Tirado said.

While the new resource buildup is concentrated to the Rio Grande Valley sector, agents say similar actions have already proved successful in other sectors in the South Texas corridor.

Castro, a supervisor in the Del Rio sector, said the increase in narcotics being apprehended by CBP agents there proves that the South Texas Campaign is working. Like the spike in area apprehensions, the increases in seizures of methamphetamine and especially heroin are of concern, he added. While marijuana and cocaine seizures dipped slightly from 2012 to 2013 in the South Texas corridor, heroin seizures increased by more than 135 percent. Methamphetamine seizures also rose.

“We’re working with the government of Mexico, and we identify certain trends that are being exploited,” Castro said. “Now what we are apprehending are the harder drugs at our [ports of entry] and at our checkpoints due to the fact that we are using the intelligence-sharing piece and our technology piece.”

Castro also credits the resource buildup in part for the capture of more convicted sex offenders trying to regain entry into the country. On April 16, the Del Rio sector announced that its 20 arrests of offenders so far this fiscal year had already surpassed last year’s mark.

“Some of these individuals indicate that the reason they were traveling in those less-traveled corridors is because they wanted to exploit the vulnerabilities” in rural areas, Castro said. “They lived there [in the U.S.], they went to work there, they feel comfortable in those environments, they committed the crime there. So most likely they are returning to that area where they feel comfortable.”

The Rio Grande Valley surge comes at a time when Customs and Border Protection, which also includes agents on the ports of entry who facilitate legal trade, is under scrutiny. Last month, a Border Patrol agent in South Texas allegedly attacked an undocumented Central American woman, her teenage daughter and another teenage girl while on duty, sexually assaulting two of them before taking his own life. And the American Civil Liberties Union has filed two lawsuits within the last year, alleging a gross misuse of power by CBP agents, including an alleged unwarranted body cavity search of a U.S. citizen in El Paso.

In response to those allegations, a bipartisan bill has been filed by U.S. Reps. Beto O’Rourke, D-El Paso, and Steve Pearce, R-N.M., that would require more oversight of the agency. On Tuesday, the U.S. office of Human Rights Watch, a worldwide advocacy and watchdog group, announced a new project intended to document cases of alleged abuses or civil rights violations on the border.

Agent Tirado and Eric Nelson, a Border Patrol supervisor for the Rio Grande Valley sector, declined to comment on the pending legislation and said they and the other agents in Texas are focused on their mission.

Even on what the officers call “slow days” in the sector, they know things can change quickly. On a recent day, as Tirado and Nelson joked about being pencil pushers now stuck in an office and reminisced about their time in the field and how they served in the academy together, they listened as the crackle of Tirado’s radio brought the device to life.

“Positive Charlie image,” the dispatcher’s voice confirmed, relaying that a camera had captured suspicious activity near the Rio Grande. Less than two hours later, Tirado was on the phone, confirming for local news outlets that aside from 31 migrants and three weapons found in a stash house in nearby Alton earlier, 15 people were apprehended when agents chased down a stolen Dodge Ram 3500.

“If I had to guess, they’d be from Central America,” Tirado said later, though he wouldn't confirm that so soon.