If you live in California, you’ve been hearing about how dry it is here. Our previous rainy season stopped abruptly just before New Year’s Day 2013. The rains didn’t return this fall, meaning many sites in the state had their lowest recorded precipitation ever. San Francisco, with records dating back to 1849, was one of those places; just 5.59 inches of rain fell during 2013. (The next-lowest total was 8.73 inches, recorded during the severe drought of 1976-77.) San Francisco’s average seasonal rainfall — dated from July 1 through June 30 to take account of the wet season — is about 21 inches. The highest rain total ever: the epic winter of 1861-62, which almost drowned Sacramento: 49.27 inches.
About the wet and dry seasons: Supposing we ever have a “typical” year, storms start arriving from the Pacific in October and keep rolling in through April. Normally, we’ll get breaks between waves of storms that bring lowland rains and huge amounts of snowfall to the Sierra Nevada. Since the state needs water year-round, since so much of it arrives in the form of snow that runs off from the mountains when the weather warms up, since there’s no way of knowing from one year to the next how much rain and snow we’ll get, we live on stored water. We have lots and lots of reservoirs.
And one reservoir that’s getting lots of attention during the current drought is Folsom Lake, on the American River northeast of Sacramento. As California reservoirs go, it’s not one of the biggest — in fact I think it ranks as the tenth largest in storage capacity, with 977,000 acre feet (if you buy the definition that an acre foot can supply about two U.S. households for a year, that’s enough water for roughly 5 million people for a year). The water in the lake is used to generate electricity, for drinking water, and for downstream farms. It’s also supposed to provide flood protection and “recreational opportunities” — swimming, boating, fishing, all those things you can do in a lake that’s in the middle of the hot, dry Sierra foothills.
Right now, Folsom lake is down to about 180,000 acre feet, about 18 percent of capacity. That’s just the sixth time since the reservoir was filled in 1955-56 that the level has fallen below 200,000 acre feet, and it appears to be the lowest the lake has ever been in January, right in the middle of what’s supposed to be the rainy season. And when I say low, I mean low. At capacity, the lake’s surface is 466 feet above sea level; yesterday, the lake level fell below 362 feet.
I drove up yesterday to take a look at the lake, the sand, the rocks, the mud, and the little bit of water that’s still spread out in the lake’s deeper channels. The weather was beautiful. People were out sight-seeing, riding bikes, meditating, even fishing, though one guy told me that when he cast his lures out into the water, they were hitting the bottom. It was pretty hard to imagine that all this was going on 104 feet below the surface of the full reservoir would be. We’ll see how low it goes. Right now, there aren’t any real storms on the horizon.
Here’s the slideshow from yesterday’s trip: