https://en.wikipedia.org/wiki/Diamond_Valley_Lake
Construction of the three dams was completed in 1999
I worked on this dam. It is not a capture dam, it is a storage dam only and depends on capture dams in northern california and the colorado river. Other dams built since 1975 are flood control dams. Diamond Valley Lake gives flexibility and reliability but not a new water source. Also the water is stored above ground so lots of evaporation losses.