The 17 western states have approximately 40 million square miles of irrigated farmland, supplied by an extensive network of irrigation canals. Without this system of irrigation, farming in most of the western states would not be possible. Irrigation systems in California were first authorized by the state legislature in the 1870's, but the statewide system was vastly expanded first in 1933, and then later in 1960 with the California Aqueduct. Without these irrigation systems, California agriculture would be vastly different.

Anytime you combine shallow water with sufficient clarity, you provide a habitat for plants to grow. Most irrigation systems in California have some level of weed infestation. Unlike the weed problems of the...