John - Oroville Lake levels are extremely low.
However, your statement "...DOWN 640 feet..." is not correct. The lake is at Elevation = 640 ft. About 250 ft below maximum level (not a 640 ft drop).
The lake fluctuates 100+ feet in elevation most years, but this recent drought is indeed severe.
Maybe the high-level water decision makers can fund / build another reservoir and dam (or maybe a dozen). Or just wring their hands for another 40 years, and just talk melodramatically about water equity and fish well-being and low flush toilets and climate change.
If California built water reservoirs at the rate of population growth over the last 50 years, there would be no water shortage today.