Four years of exhaustive study went into determining the need for more storage and selecting the best site. Metropolitan looked at 13 sites that met basic criteria. And chose the Domenigoni Valley for several reasons:
Elevation of the valley was excellent approximately,
1500 feet above sea level, creating sufficient drop to
provide gravity flow to 95 percent of Metropolitan's service
area;
It would be an added source of hydroelectric power - as water rushes out of the reservoir, it creates a tremendous amount of energy that is converted into electricity by turbine generators. A maximum generation of 40 megawatts will be enough for 40,000 homes for a year;
Location to Metropolitan's existing infrastructure was perfect a few miles south of the San Diego/State Water Project canal juncture permitting tie in of the current delivery system with the new by basic engineering;
Water quality would improve by tying the new lake into the existing infrastructure and enabling Metropolitan to better blend and monitor its two water sources the Colorado River and the State Project;
Material for construction was extraordinary and located
right at the site the valleys and surrounding areas
are situated on the Perris Block, the highest quality
quartzite in the region;
The overall long-term benefit of Diamond Valley Lake
it will provide critical water storage south of
the Sacramento-San Joaquin Delta and within the urban
Southern California region west of the San Andreas Fault.