Water years in California go from Oct 1 – Sep 30. The drought has broken, and spectacularly so. It’s already been one of the wettest years ever. If rainfall in the remaining months is normal, it will be the wettest year on record. Amazingly, more storms are coming, and they will fall in northern California watersheds and the Central Valley. This is great news for California, and for Southwest states, because the more water California has, the less pressure there in on the crucial Colorado River, whose water is shared by seven states and Mexico. Several major reservoirs in California are above their historical capacity now, which is way better than things were last March.
Now that we’re more than 2/3 of the way through California’s wet season, it’s pretty clear that much of the state has experienced its wettest 3-6 month period on record. Virtually every corner of the state is above average to date, though anomalies have been much more impressive in the north. The Northern Sierra watersheds are currently sitting at just above 200% of average precipitation for the season to date–a rather extraordinary statistic. If California receives at least average precipitation for the rest of the season, 2016-2017 would become the state’s wettest Water Year on record.
What is pretty clear, though, is that this year’s extreme wetness on the seasonal scale has pushed parts of California’s aging water infrastructure to the brink.