Varying Water Levels at a Few Reservoirs in California

When MOH and I drove to Butt Valley Reservoir a couple weeks ago, we were surprised by the lake low lake level: it looked lower than we remembered seeing it, although we haven't been frequenting the area routinely for several years.

Standing on a wider-than-usual beach near the boat ramp on the east shore, looking south. 

The boat ramp is the dark, shadowed line below the tall trees on the same shore I'm standing on. The dam is a ways around the corner to the southeast behind the tall trees.

This picnic table from the day use area was moved out onto the beach, presumably as a prank. Photo from August 22nd.

A few days later the same picnic table was at water's edge.
Photo from August 26th.

Although the angle of the photo is a bit different, you can see that the lake has risen by looking at the boat ramp and a couple logs in the background, not to mention the trees. In addition, the beach on the far shore is no longer visible.

It isn't really normal for water levels to be rising this year in California reservoirs, but the lake level in Butt Valley Reservoir (the lake is alternately called Butt's Lake, Butt Lake, and Butt Valley Lake) is notoriously variable. In fact, swimmers and boaters are warned to watch the lake level, as it can rise suddenly if water is released from the next lake up the ladder, which is Lake Almanor. Unfortunately, I didn't get a picture of the warning sign.

Indeed, in case I didn't believe my eyes (or you don't believe my photos), Butt Valley Reservoir contained 35,117 acre feet on August 22nd (probably a permalink, or play around with the dates yourself) and 41,627 acre feet on August 26th (same chart). Total storage capacity of the reservoir is 49,800 AF. The chart of reservoir storage for the month of August can be seen here (a probable permalink).

Meanwhile, the lake upstream in the Feather River watershed so-called "Stairway of Power" was dropping (tabular data), especially after August 21st (graph).

We've all seen some of the recent pictures of the main reservoir at the downstream end of the Feather River system (Lake Oroville above Oroville Dam). I wouldn't mind posting some of these here, but surprisingly, CDWR describes these photos as public domain and copyrighted and not for redistribution at the same time (right click on this one, for example). Instead of photos, view the Lake Oroville storage chart for all of 2014 here (should be a permalink).

What we can discover through various CDEC links and calculation tools, is that the May 2014 peak at Lake Oroville of 1,877,682 AF was considerably below the average May peak of 3,042,972 AF. I've read in comments that the 1990, 1991, and 1992 years were worse California drought years than 2014 (perhaps based on statewide storage, rain, runoff, or wishful thinking?), but at Oroville, storage at the beginning of September was a little higher in all three of those years than it was this year: 1,188,782 AF in 1990, 1,392,300 AF in 1991, and 1,401,554 AF in 1992, compared to 1,100,873 AF on 9/1/2014.