6-lanes highways are great for connecting human communities, but at the same time they sever the pathways of animals across their habitats, decreasing their foraging area and the diversity of their gene pool.
Recognizing this issue, the Arizona Department of Transportation has included two wildlife crossings in the project to widen Oracle Road, the first one of which, near the Pinal County line, was dedicated this past May. The crossings allow wildlife to migrate between the Santa Catalina and Tortolita mountains without having to cross at street level, which is much safer for the animals, as well as for the drivers crossing their path. They consist of a combination of an overpass and an underpass, because some animals, like javelinas, do not like bridges and others, such as deer, do not like tunnels.
Where a road may be a connection to some and a barrier to others, a wall is a barrier to all. Throughout history, nations have employed walls to block aliens from getting in or, in at least one notorious case, its own people from getting out. There is the Great Wall of China, dating back to the 7th century BC, built to keep out the Mongols. There is Hadrian’s Wall in Great Brittain, built to keep out the Picts and more recently, Israel has built a wall to keep out the Palestinians.
And now there is also the U.S.-Mexico border fence. As yet it is just bits and pieces, but there is is strong push to connect these up in order to make the southern U.S. border impregnable.
There is considerable disagreement on the effectiveness of this approach for immigration control and on the feasibility of fencing the 1200 miles of border made up by the Rio Grande. At a cost of about 20 million dollars a mile, the expense is also a consideration, all the more since the Mexican government has emphatically stated that Mexico will not contribute to the project in any way.
In addition to the political and economic issues, there are concerns about the environmental impact of such a structure. Among these, that it will severly disrupt the migratory patterns of land animals, with consequences for their sustenance and procreation; that the around-the-clock artificial lights, increased traffic and other associated incidentals will cause disorientation in land-bound and airborne animals alike; and that it will significantly change the water flow and the patterns of sedimentation and erosion. A case in point: in 2008, a barrier erected by the U.S. Border Patrol in a cross-border storm drain near Nogales blocked flood waters, causing serious flooding across the border, in which 2 people died.
Under pressure to come up with a comprehensive solution to the problem of illegal immigration, the U.S. Congress has allowed the Department of Home Security to waive compliance with the National Environmental Policy Act and the Endangered Species Act and revoked the federal courts’ jurisdiction to hear any claims against the waiver authority, unless the claims successfully present a constitutional challenge. DHS put a moratorium on further expansion of the fence in 2009, but gave it new life two years later when it canceled plans for a virtual border fence, using electronic devices, as recommended by the Environmental Protection Agency, because it would not impede the course of nature.
One solution would be to go the Oracle way and build bridges over it for the deer and tunnels under it for the javelinas and for the water. But then, it would be just as well to built no wall at all.