But the statistics suggest that an impermeable border is a fantasy, no matter how much money and technology is thrown at it.
Customary rangelands and migratory transit routes are shrinking in the face of spreading cultivations, intensive cattle production, mining, oil extraction, land privatization, protected areas and impermeable international borders.
Most of these countries are either source and/or transit countries for irregular migration to the EU.5 Candidate countries, on the other hand, are already obliged to make their borders impermeable against irregular migrants and other undesirable persons.
The idea was that the dark line would reinforce the biased notion that borders are impermeable, and that states are therefore meaningful categories to rely on for decision making.
A study published in this month's edition of Biological Conservation warns that the black bear population just north of the border in Arizona may be threatened by the increasingly impermeable barriers at the border.
The paddies have an impermeable subsoil and are bordered by earthen bunds to hold an average of 4 6 inches (10 15 centimetres) of water in the field for three-quarters of the growing season.
The units outcropping at Yeniçıkrı basin, from bottom to top, respectively, Paleozoic marble, which is the main reservoir rock for hot and cold water, are bordered by impermeable schists.
The intifada years, between 1988 and 1991, when the nightly doses of televised repression were confined to the occupied territories, helped nurture a comforting confidence that the "green line" border was somehow impermeable.
Is it because we're seen as haughty or we think we're so right?" That question hangs in the air here, with people acutely aware that no border can be made impermeable.
In this scenario, guns (particularly assault weapons) would be much harder to come by; borders would be secure, but not impermeable; heavy security would be focussed on vulnerable locations, rather than everywhere; and the burden of preventing terrorism and other violent attacks would fall on the police, the intelligence agencies, and a vigilant public.
