Water Supply Update

December 1 is an important time for a water supply update.  This is usually when we hear from the California Department of Water Resources as to the “Allocation” of water to the State Water Project.  As of this morning, we have seen nothing on their web site, but the initial allocation for 2013 should be out soon.  As always, it will be based largely upon the water currently in storage in the SWP.  The status of the largest component of that storage, Lake Oroville,

This is not Lake Oroville, but it is a lake.

can be found at:


The graph shows that we are one million acre-feet short of where we were last year at this same time, but almost exactly where we were two years ago.  That’s because two years ago we had an epic Winter/Spring precipitation season, but last year was a real dud!

In fact, last year was such a disappointment that the DWR actually had to drop its initial allocation as the poor Winter progressed.  That’s not unprecedented, but it is extremely rare.  Like most of us, DWR hates to over-promise and then under-deliver.  So the December 1 initial allocation is notoriously conservative.

Two years ago, with similar storage conditions, the initial allocation was 25 %.  We should expect something similar this time.  Also two years ago, within one month, the allocation was raised to 50 % because of the tremendous precipitation early that December.  We suspect that DWR may be waiting to see what the extent of precipitation will be from the huge storm that is currently blessing us with so much rain.  Waiting  a few days could avoid the huge change in allocation over such a short time span, such as we saw in 2010.

Keep praying for rain — and snow!  Stay tuned to MOST for periodic water supply updates … and also for the best in online continuing education for water system operators!

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