I went on a tour of that place while it was under construction. It was like one of the Seven wonders of the world to me. I think it was green light 24hrs a day for like 5+ years. They just capped a whole valley on both ends and also a side saddle dam. The dams on each end are roughly two miles long. The saddle dam is 1/2 mile long. The valley floor is almost 5 miles long. They basically sifted through all the earth , separating everything from clay which was used as the core of the dam, layering bigger and bigger... sand then pebbles then baseball rocks etc etc up to refrigerator rocks on the outside of the dam. The core is packed so hard a square foot weighs 250 lbs and can't be scratched with a icepick. The place was also loaded with Mastadon and other fossils. Skulls the size of volkswagons are on display at the visitor center. Six month emergency supply of gravity fed water to all Southern California.
http://en.wikipedia.org/wiki/Diamond_Valley_Lake
Impressive place....They were suppose to put nice campgrounds in. Any word on that? See if you can convince them to allow Sit on tops if we plug up the scupper holes.