San Diego and all of Southern California get the majority of their water from the Colorado River Aqueduct, and the best source of information is the Metropolitan Water District's tour of the Colorado River Aqueduct and State Water Project/Bay Delta Tour. The tour of the Colorado River Aqueduct tour covers the reservoirs, dams, canals and pumping stations which deliver water to San Diego and 5 additional counties in Southern California which was built in the 1933-39. The water in the aqueduct covers 242 miles in the journey from Lake Havasu to Lake Mathews. Each of these tours is 2-3 days long, so it is a commitment for both the participant and the Water Authorities to gain and provide a tremendous perspective of the system.
This tour begins early on Friday morning where the first stop is the current renovation of the San Vicente Dam by the San Diego Water Authority. This renovation will increase the height of the dam by 117 feet from the former height of 220 ft. This expansion to 337 feet will increase the capacity of the reservoir from 90,000 acre feet (AF) to 152,000 AF (One acre foot of water is approximately equal to a football field covered by one foot of water.) Considerations in engineering of the dam include matching the strength of the new addition to the dam to the existing dam and a sophisticated layering of concrete to build up the dam. The dam is expected to be completed in 2013.
The Robert A Skinner Water Treatment plant and its 1 mega Watt solar photo voltaic system are the next stop. Here water from the Colorado River is mixed with water from the State Water Project. During the processing quagga mussels, an invasive species native to eastern Europe that clogs intake pipes, are controlled and micro-organisms are eliminated. For the disinfection, ozone is utilized. Ozone is bubbled through the water(see slide show) eliminating 99.9% of the micro-organisms. The use of ozone rather than chlorine has the benefit that there is no out gassing to the surrounding environment. It cleanses the water. The plant is considering adding additional solar facilities to further offset the cost of electricity required for processing 630 million gallons of water per day. The plant manager and tour leader stressed that all of the systems have double redundancy to assure safe water continues to be delivered to 18 million people served in Southern California . For example, if there is a power outage there are back-up generators and back-up backup generators. Following the canal back a step, we reach Diamond Valley Lake.
Diamond Valley Lake is the reservoir on the tour which supplies Colorado water to the Skinner Water Treatment plant. This lake was finished in 1999 and has a capacity of 800,000 AF or 260 billion gallons of water. The lake is part of the Water District's strategy to provide holding facilities in case the water supply is cut off or limited by natural or man-made events. The Colorado River Water has reached Diamond Valley Lake through the 13 mile long San Jacinto tunnel moving water from the area around Palm Spring and the Coachella Valley to the north.
To reach the San Jacinto tunnel from Lake Havasu, the gravity feed system is supplemented by 5 pumping stations. The water begins at Lake Havasu and is lifted at the Parker dam. Each impeller requires 6.5 mega Watts of electricity supplied by the hydro-electric plant in Hoover Dam. On January 26th four pumps were running. This significant draw of electricity of one pump make s it clear how 25% of the power generated in California is dedicated to the transportation and conditioning of water. After the water is pumped up it flows down powered only by gravity. The water takes a days long journey across the desert region to reach the San Jacinto tunnel then Lake Mathews.
One of the moments of insight on the tour, was when the guide pointed to a trestle train bridge that ran overhead and stands approximately 70 above water level. This bridge was built over 100 years ago and before the Colorado River system was put in place the flood waters would reach the rails of the bridge. This flooding was also responsible for the fertile farmland that exists through this valley.