Dr. Todd Bostwick | Photo courtesy State of Arizona Research Library   Hohokam farmers built the largest system of canals in the New World between 500 CE and 1450, making a network of canals in Arizona’s Salt River Valley totaling more than 1,000 miles. It was a marvel of organic engineering in the pre-industrial era that helped the ancient people sustain their crops and civilization. Archeologist Todd Bostwick has studied the Hohokam and Arizona’s ancient...