The All-American Canal, more than 3,000 miles of freshwater canals and drains, pulls 3.1 million acre-feet of Colorado River water per year to irrigate 500,000 acres of farmland in California’s Imperial Valley. The Water Department of the Imperial Irrigation District (IID) maintains the system.Where the open canals cross roads or bridges, the water funnels through 48- to 72-inch concrete siphons, which trap materials. The biggest debris contributor is silt runoff from the fields. The Friday night ritual of kids throwing bales of alfalfa into the canals ranks second, followed by trash tossed from passing vehicles. Blockages were a constant challenge,
