Viewed from above, Candelaria shimmers like a mirage in the desert, rising up in wavering relief from a vast scrubland of creosote and ocotillo at the edge of a bone-dry riverbank. The mountain ranges that surround the town are cloaked in swirling dust; the Rio Grande, which once flowed in a crooked course behind this community of 55 residents, largely disappears as soon as it reaches Candelaria. There’s scant evidence of human life at all, save for a spray of mobile homes and other modest dwellings that line the strip of sun-scorched asphalt running through the middle of town. But to its residents, this hamlet in far West Texas is no illusion. A fifty-foot water tower overlooks the unincorporated border town; at its base is a…