Water Supply Update — 2011 Initial Allocation

Well, we’ve “weathered” — if you’ll pardon the expression — the dry months of summer and fall, and we have seen the normal declines in water levels in the major storage reservoirs of the state. From a water supply standpoint, how do we stand this year, in contrast to last year?

Each year, the California Department of Water Resources is required to provide its customers, the State Water Contractors, with an “Initial Allocation.” This is the percentage of their “Entitlement” that they can expect to receive in the coming calendar year.

The Entitlement is the quantity of water for which each Contractor pays. The total of all the entitlements from the State Water Project is about 4 million acre-feet per year. (An acre-foot is the volume of one acre of area with a depth of one foot of water, or about 325,000 gallons — and close to the typical annual consumption of a single family home.) It is important to realize that, although you definitely pay for your full Entitlement, the State Water Project can only deliver water that exists. So, the actual deliveries of water are often less — sometimes far less — than the Entitlement.

The Initial Allocation is DWR’s best guess for how much of your Entitlement they will be able to deliver to you. And DWR is in a bind here: their Initial Allocation is due by December 1 — long before any real rain or snow happens. So for the Initial Allocation, they must rely on the only “real” water they have: the water in their reservoirs.

We tracked reservoir levels all through last winter and spring — and I expect to do that again this year. We saw a very good increase in storage, thanks to a pretty good rainfall/snowfall year in 2010.

The Initial Allocation for 2010 was only 5 percent — it was pretty close to panic time. Thanks to the storage increases in the past year, this year’s Initial Allocation is 25 percent. See:

Well, 25 percent is much better than 5 percent, but nowhere near 100 percent. As we saw last year, DWR revises the Allocations each month, in response to the actual rainfall/snowfall conditions. So with a “normal” or nearly normal precipitation year, we should expect at least modest increases in the Allocation over the next few months.

However, if we encounter a dry year, 25 percent might be all we get. Pray for rain!

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