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California Water Season and Drought Update

By: Christopher C. Burt, 7:05 PM GMT on July 07, 2014

California Water Season and Drought Update

The water year for California came to a close on June 30th (the water year being July 1-June 30) and it was one of the driest on record for the state as a whole, preliminarily ranked as the 3rd driest such. Here are some details.

Final water-year precipitation totals for selected cities in California arrange geographically from north to south.

As one can see in the table above the dryness was evenly spread statewide with percentages of normal ranging within a narrow 38%-53% margin. Given the size of California this is exceptionally unusual (it would be like the Northeast or Southeast of the U.S. experiencing similar precipitation departures for their entire respective regions. For California it appears 2013-2014 will go down as the 3rd driest water season on record (with around 12.44” statewide average) falling short of the driest such of 1923-1924 (11.24”) and 2nd place 1976-1977 with 11.36”.

In spite of how dry it was this past year, there were no all-time records set for minimum seasonal precipitation at any sites of consequence. Below is a chart of how the rainfall in the greater Los Angeles area ranked relative to all-time records:

Table from NWS-Los Angeles office.

The past water season was not record-breaking precipitation-wise but the drought is close to if not already the worst in modern state history. This is because the precipitation for the 2012-2013 season was also exceptionally minimal: the 17th driest on record (since 1895) as was 2011-2012, the 19th driest on record statewide. For Los Angeles, the two-season total of 2012-2013 and 2013-2014 has been the driest ever observed:

Table from NWS-Los Angeles office.

The latest drought monitor (released on July 3rd) has shown that the portion of the state experiencing ‘Extreme Drought’ (D3) and ‘Exceptional Drought’ (D4) is gradually expanding week-by-week.

The areal coverage of ‘Exceptional Drought’ has increased by 10% statewide over the past week (as of July 3rd) according to the latest drought monitor report. Map from NOAA et al.

Surprisingly, water restrictions remain voluntary for most of the state’s residential consumers and most of the reservoirs still seem to have fairly adequate water supplies, averaging about 45% of normal capacity for this time of the year. This is probably because of the decent snowfall that occurred in February and March, now melted and run off, which helped stabilize the reservoir levels. Of course, as the next several months wear on with no chance of any further significant precipitation until, at best, next October, rationing is almost certainly on the horizon. Last January California Governor, Jerry Brown, requested consumers to cut their usage by 20% but so far the reductions have only amounted to 5% on average statewide.

Aside from the drought, the biggest fear California’s residents face at this time is that of wild fires. Already some unseasonably early fires have broken out. The latest being two in Napa County north of San Francisco. The ‘Butts’ fire burned 4,500 acres and destroyed two homes last Thursday-Friday, and now a 6,500 acre fire, the ‘Monticello’ fire is out of control and threatening more homes in the same region.

Christopher C. Burt
Weather Historian

Extreme Weather Drought Precipitation Records

The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.

Reader Comments

Lake Mead, Nation’s Largest Reservoir, To Reach Record Low This Week

The last time Lake Mead, the largest reservoir in the United States, reached maximum capacity was 1983. This week the lake, located along the Colorado River near Las Vegas, Nevada, is expected to reach a new milestone — its lowest point ever.
Formed by the Hoover Dam, Lake Mead has been suffering for years as an expansive drought across the West, coupled with rising temperatures and populations, has overstressed the massive man-made body of water. According to forecasts from the federal Bureau of Reclamation, water levels will fall this week to their lowest since it was first filled in 1937. The lake, which provides water for 20 million people across the Southwest has been losing water for over a decade and is currently at about 40 percent capacity.

kill your lawn now or you will be forced to later... along with everything else you use water for
The Conditions for Major Reservoirs map. Trinity, Shasta, Oroville, New Melones, San Luis, and Don Pedro account for 81% of the capacity on the map. On 7/6/2012 their aggregate holdings were 13,183TAF. On 7/6/2013 the figure was 10,064 TAF. Their total on this posted chart aggregates 6,588 TAF. This map is accessible online and one need only input a date to get % of capacity. These figures indicate a loss of 3,119 TAF from 7/6/2012 - 7/6/2013 and a loss of 3.476 TAF from 7/6/2013 - 7/6/2014.

The two year drought has cut the water supply in these major reservoirs in half. And it will be months before any replenishment. One need only do the math. If the drought persists and no measures are taken, the 6,588 TAF will be exhausted in two years. Perhaps California will be lucky in 2014-2015. Then again, luck is something for the players in Las Vegas who bring money to burn. It would seem at these water levels, it is time to take things seriously instead of making bets.
The 5% water savings quoted in the article is misleading. This does not include permanent water savings from previous years (such as low flow showers, toilets, sinks, elimination of evaporative coolers, and smarter agriculture).

Arid-condition agriculture is still not the norm (nighttime only irrigation, drip irrigation, ground cover, mixed crop, elimination of furrows, and domestic water recycling). In addition, drip irrigation reduces the danger of vegetables carrying hazardous waterborne bacteria.

California homeowners still love their lawns. Plants native to arid areas use much less water (internal water storage, waxy coating, and color change during dry months). Better yet, light colored gravel covered with light colored sand requires no irrigation, but controls runoff during rainstorms.

An El-Niño ocean current is predicted for the coming rainy season. This usually indicates heavier than average rain in California.
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