As CBS News Correspondent Sandra Hughes reports, aggressive enforcement efforts like Operation Gatekeeper in San Diego have reduced the flow of migrants. But three times as many immigrants have perished this summer in the desert than last.
Critics claim Immigration and Naturalization Service policy blocking other sections of the border pushes people into the dangerous desert. Border officials deny that, blaming smugglers for the new human pipeline.
Whatever the cause, federal agents who once monitored the border are now trained in emergency medical response for the search and rescue of migrants who attempt to cross the desert with too little water to survive.
"Every trail that we're on now is a lifesaving mission because we know if we don't catch 'em and they get past a certain point it's many, many miles without water," said agent William Hollon of the Border Patrol's Operation Sky Watch.
The women, children and men who walk up to 50 miles in the desert looking for the American Dream often come hopelessly unprepared.
"Most of them just come with one gallon of water" and a small supply of food, said Agent Rafeal Estrada, which "might last you half an hour."
For the border agents, there is no time to spare when temperatures regularly top 110-degrees. On motorcycles, by foot and in aircraft, they look for illegals to save rather than stop.
As part of a recent emergency mission along the border, two illegal immigrants were airlifted to safety. They had wandered the desert for three days before border patrol agents found them exhausted, dehydrated and unable to walk another mile.
Also recently, a group of 10 illegal immigrants each paid $1,000 to a smuggler who drove them over the border and abandoned them in the middle of an active army bombing range.
"The smuggler left us in the middle of the desert," said Veronica Romero, a woman in the group. "He said he was going to get water, but he never came back."
The agents rescued the 24-year-old woman and her eight-month-old daughter. Before the agents arrived, Romero had torn apart a prickly cactus in a desperate attempt to get liquid for her baby.
"I was sure I was going to die in the desert with my daughter. I had no strength left. I couldn't walk. I couldn't even save myself or my daughter in that heat," Romero recalled.
INS officials expected the rugged and treacherous terrain in the Arizona desert to act as a natural deterrent against illegal immigration, but it has not stopped the flow of human traffic.
Even if it means death, many are willing to take the risk.
"There is no work in our town, this situation is bad," said Romero. "We had to take the chance."
The increasing dangr of crossing the border led the U.S. Border Patrol to begin a Border Safety Initiative in June 1998 that was, according to the Border Patrol, "designed to educate migrants about the risks and dangers of crossing the border illegally and to assist those who do not heed the warnings."
It was upgraded in June 2000 to include water rescue training. In July, Operation Sky Watch was launched, involving 16 planes.
Through the first eight months of fiscal year 2000, or June 15, 2000, the Border Patrol had rescued 1,104.