|La Grange Dam in quieter times (Source: http://www.turlockjournal.com/archives/29341/)|
The dam has a unique structure, being composed in large part of locally quarried metamorphic rock blocks (about 25% of the volume of the dam). The rugged texture of the dam face is distinctive. The rest of the dam is composed of concrete. It holds back a mere 500 acre feet (in contrast, Don Pedro Reservoir upstream has a capacity of 2.04 million acre-feet).