Sheriff Joe Arpaio was the first person to set up "Tent City" in Maricopa County during the year of 1993 as an extension of the Maricopa County Jail system. Eventually later on, Sheriff Joe Arpaio would approve more building of these "Tent Cities" around the state of Arizona and not just Phoenix metropolitan area. By 2009, there were more than 15 Tent Cities. These Tent Cities are similar to prison and jail of course. These Tent Cities are run like a prison system obviously.
And yes, Sheriff Joe Arpaio has even went to the extent of describing Tent City as a concentration camp. Lawyers and attorneys have questionably wondered and continue to fight over the constitutionality of Tent Cities. Tent Cities are criticized by human rights groups stating there are violations of human rights and constitutional rights going on there. In 2010 even more tent cities were built.
Sheriff Joe Arpaio runs law enforcement for Phoenix along with the state of Arizona with an iron fist. We all know that Sheriff Joe Arpaio doesn't play around when it comes to law enforcement and politics.