The Secure Border Initiative is a reality in much of Arizona. Border Patrol is nearing the completion of the large fence separating the U.S. from the Mexico border, with approximately 230 miles of the anticipated 252-mile barrier complete.

The Tucson Border Patrol Sector, the busiest in the nation, shares 262 miles of border territory with Mexico, most of which will have fencing when the project is complete

Congress approved the fence in 2005 and has since spent $2.7 billion building it, which is an estimated $3.9 million per mile.

 “Almost 230 miles of different styles of fence have been built in the Tucson sector including Douglas and Nogales,” said Mario Escalante, an agent with the Tucson Sector Border Patrol. “There is pedestrian fence, vehicle barrier fence, permanent and temporary fence. This is part of our tactical infrastructure and we build infrastructure where we need it. The whole border does not need to be fenced.”

The areas of the border that will not receive fence are those that have land barriers such as mountains. Escalante said that it is too difficult to build effective fencing on that terrain.

The new pedestrian fence near the Nogales border towers over the old fencing, which can still be seen in parts of the town. The new fence is 14 to 16 feet tall and goes four to five feet into the ground.

“It is effective in the sense that it slows people down,” said Michael Scioli, a border patrol agent. “Each of the poles has cement in them and the area underground is buried in cement. The fence is also see through now, which helps us a lot to anticipate what is on the other side.”

The old fence was made up of panels and wire fencing.

“People bring blow torches and cut holes in the old fence,” Scioli said. “They can’t do that with this new fence.”

The new, see-through fence gives agents an advantage, Escalante said.

“With the pedestrian fence, we can now see on the other side, which is something we couldn’t do before,” Escalante said. “If there is something against the fence or if there are people staging something on the other side, we will know now, which helps agents to prepare for whatever is happening.”

Escalante said that the fence has multiple purposes, the first of which is to deter illegal immigrants. It is not only harder to get through, but it goes on for miles and establishes challenges to people attempting to cross the border

“Say a smuggler has a group of older ladies, they won’t climb it,” Escalante said.

Another purpose of the fence is to keep illegal immigrants out of border communities.

“When you have a community, like Nogales, you see how close the houses are to the line,” Escalante said. “If there was not a fence, people would just run across into other people’s houses.”

He added that people in the community often get upset when there are people running through their yards and their things get stolen

“It makes you feel good when people from the communities come and thank you because things like that have stopped,” Escalante said. “With the fence, people are forced to go around the fence and not through communities. This gives us hours or days to make apprehensions.”

The fence has been controversial since its start, causing heated debate between politicians and activist groups.

“The fence has the potential to keep certain species out of their habitats,” said John Windes, a habitat specialist with the Arizona Game and Fish Department. “It’s like putting a new door in your house so you can’t go from one room to the other. You can’t get somewhere you normally go in your daily routine, and that is important.”

The other potential problem that Windes sees is that the fence could create a lack of genetic variation amongst animals.

“If there is no movement between populations, you get habitat fragmentation,” Windes said. “Each range has a specific genetic variation for the region they are in. The same species often have different genetics in different mountain ranges. If they are allowed to move mountain ranges, their genes move, but if the gene flow ceases, there is a lot of potential for bad things because there is limited genetics.”

There is no set completion date for the fence yet, Escalante said.

“I couldn’t say if (the fence) is done in this sector,” Escalante said. “We’ll support whatever Congress wants us to do if they decide to build more fence.”