Developed by the Metropolitan Water District (MWD) during the 1920’s. Twelve expert draftsmen created more than 250,000 pieces of fiberboard to depict the 50,000 square miles of land surrounding the aqueduct’s route. After a 6-year process, the MWD built the “Big Map” and carried it to Washington, D.C. during congressional hearings. The Map weighs close to 5 tons and is designed to come apart like a giant jigsaw puzzle.

The service of the aqueduct, each year more than 1 million acre-feet of water flows through the 242-mile long Colorado River Aqueduct from Lake Havasu to Lake Mathews and, finally, to Metropolitan’s 810,000 acre foot Diamond Valley Lake in Southwest Riverside County. The Flow of water can be tracked by what’s known at the Metropolitan Water District of Southern California as the Big Map.