Look in the mountains to the west of Tucson and your eye will be drawn to a set of shimmering rectangles that dominate the valley floor. These are not solar panels, nor parking lots, nor any nefarious construction. They are immense pools of water, part of the Central Arizona Project. Tucson’s need for water has…

Late afternoon sun reflects from deeply incised bedrock. How large is this scene – are we looking at a canyon hundreds of feet deep, or instead at a small rivulet? The stream here is nearly one foot wide. You probably guessed that correctly, but how? The mind is adept at picking up on small cues…