Updated Forecast of Final California SWP Allocation: 20%

Mother Nature was kind to California in February where monthly precipitation exceeded averages for the first month this water year (monthly chart).  This higher precipitation increases Hydrowonk’s prediction of the expected final SWP Allocation to 20%.  There is a reasonable chance that the final SWP Allocation will be zero.

Monthly Northern Sierra PrecipitationHydrowonk’s predictions are based on a study of the historic record of final State Water Project Allocations.  The model relates SWP allocations to the amount of water in storage at Oroville at the beginning of the water year and cumulative precipitation as measured by the Northern Sierra 8-Station index from October through April. 

Despite Nature’s bounty in February, cumulative precipitation remains significantly below average (slightly higher than 40% of historical average through February).  Therefore, the predicted final SWP Allocation remains at historical lows.

Cumulative Northern Sierra Precipitation

There is much uncertainty surrounding Hydrowonk’s prediction.  As shown by the probability distribution of predicted final SWP Allocations, the expected 20% allocation is the most likely number, but a zero allocation is almost as likely.  There is less than a 20% chance that the final SWP Allocation will exceed 30% and only a 6% chance that the final SWP Allocation will exceed 40%.

Probability Distribution of Final SWP Allocation

Mother Nature threw California a bone in February.  While helpful, the situation remains “bone dry.”

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About Rodney T. Smith

Rodney T. Smith, Ph.D., President of Stratecon Inc.—an economics and strategic planning consulting firm—advises public and private sector water users on the acquisition, sale and leasing of water rights and water supplies in the western U.S. He is routinely involved in economic valuation of water rights, water investments, and negotiation of water acquisition and transportation agreements and has served as an expert witness in the economic valuation of groundwater resources, disputes over the economic interpretation of water contracts, economics of water conservation and water use practices, and the socio-economic impacts of land fallowing. For more information, see www.stratwater.com.