Olivenhain Dam, San Diego County
The 308 by 2,400 foot Olivenhain Dam appears to be nearing completion in this photo, although it’s still under construction (there’s a yellow crane at the centre). As part of San Diego County Water Authority’s US$827 million Emergency Storage Project, the dam does not block a stream or river but instead boxes off a 200 acre man-made reservoir (to the north) which will be filled with 7.8 billion gallons of imported water. The project is expected to be completed in 2010 (more information). Thanks: Papapenguin