How low can it go?

This site has an eye-opening visual that's you'll see as soon as you scroll down to the reservoir section. Once the bar graph appears, keep scrolling slowly as you watch the date reported at the bottom right.

You'll see a bar graph that shows reservoir levels starting in January 2011 through to March 2015. It cycles the way reservoirs normally do, but you'll notice that it never quite tops up as per normal starting in 2013, never mind how low it goes in late fall.