That's not to say the flow of drugs has ebbed.
Some 2,187 pounds of narcotics were seized by the Border Patrol in April, up from 572 pounds seized in March. That sharp increase was due to one large seizure of more than 1,000 pounds of marijuana in April.
Some 10,500 pounds of marijuana and 121 pounds of cocaine has been seized in the sector this year.
Of illegal immigration, Border Patrol officials can only speculate why the numbers have decreased.
Border Patrol spokesman Arturo Sandoval said one reason there are fewer apprehensions is there are fewer people trying to cross illegally because there is more faith in the government under President Vicente Fox. Sandoval said the entire Southwest border is experiencing a decrease in apprehensions.
He added while trust in Fox may be one reason for the drop-off, he said a stronger force is making a difference in deterring illegal immigration.
He credited the El Centro Initiative, a plan the Border Patrol engaged starting in 1997 to focus efforts on the "line," meaning the border fence area.
The numbers of Border Patrol agents have increased in the El Centro area. Last year there were about 380 agents in the Valley. This year that number has increased to 500 and more are on the way, Sandoval said.
He also pointed to a new $5 million surveillance system in the Calexico sector of the Valley.
There are 18 surveillance video cameras along the border that are on long polls looking down at the border fence. The cameras are monitored 24 hours a day and there are plans to bring in 20 more cameras for the El Centro sector.
Agents on the line Tuesday said they still are kept busy each day by those trying to cross illegally.
Young people in particular, nimble and strong enough to scale the fence, regularly make the attempt.
Agents interviewed along the border agreed to talk on condition their names would not be used.
As the agents watched the border, children on the U.S. side played tetherball in a park just beyond the border fence, seemingly unaware of the Border Patrol sport-utility vehicle parked not far away.
On the Mexican side of the border other youths walked down a street, not bothering to look at the border fence.
"You try to stop them before they even come down the fence," said one agent sitting in his white SUV with the Border Patrol emblem on it, a familiar sight in Calexico.
That agent said, "It's not as busy as last year or the year before, but I don't think it is ever going to stop."
Another agent said the video cameras and sheer numbers of agents make a difference. He said if people know they can get caught, they are not going to try to cross.
Still, that agent said those entering the county illegally are willing to risk all, and they do so by using the highly polluted New River to cross the border.
"It's almost guaranteed access," the agent said, adding, "The odds of getting caught are 50 percent or less."
That agent said some 50 to 100 people a night use the New River to cross and during the summer that number can go up to 200 a night.
He said they use the New River to float 10 miles north into the country.
"They know we won't touch them," the agent said, pointing out the New River carries 15 different diseases.
Another agent said in a course of a day he may see as many as 20 people attempting to cross. He said most will hop the fence back into Mexicali when they spot Border Patrol agents. He said a small number may make it across.
He said all agents can do is their best to control the flow.
"When you control it, you are pushing it east," the agent said, adding it was Project Gatekeeper in San Diego that controlled illegal immigration in that area and increased activity in the Valley.
That agent said as illegal immigration is controlled in the Valley, the flow will move elsewhere.
Staff Writer Darren Simon can be reached at 337-4082.