Is DWR’s announced zero allocation for California State Water Project (“SWP”) consistent with predictions from Hydrowonk’s study of the historic record of final SWP Allocations? Yes
On January 30, I posted that, based on a study of the historic record of final California’s State Water Project Allocations, the final allocation for California’s State Water Project in 2014 is expected to be 12%, with one-third chance that the final SWP allocation will be below the initial 5% allocation. On January 31, California’s Department of Water Resources dropped the SWP Allocation to zero “to preserve remaining supplies.”
As stated in my earlier post, the analysis placed a 2% minimum SWP Allocation, which would be only 83,000 AF of SWP water allocated. I admit that DWR surprised me by going to 0%. Should have stayed with my model.
The chart below shows the Reliability of the Final SWP Allocation with and without the 2% minimum.
With the 2% Minimum, the Expected Final SWP Allocation is now 11%. This is below the 12% published earlier because I now have data from the January Northern Sierra 8-Station Precipitation Index. Adding the January data into the analysis lowered the ratio of cumulative precipitation to average precipitation for 1990-2013. I use this ratio to project precipitation for February through April. With lower cumulative precipitation now projected through April, the expected Final SWP Allocation is lower.
Without the 2% minimum placed on the predictions, the Expected Final SWP Allocation is 10%. There is less than a 25% chance (actually 23%) that the Final SWP Allocation will stay at 0%. Overall, there is a 60% chance that the final SWP Allocation will be less than 10%. On the flip side, there is about a 40% change that the Final SWP Allocation with be greater than 10%.
The conclusion of my earlier post may warrant repeating:
Mother Nature will not bail out California. In the 1991 drought, the Final SWP Allocation was 19% when there was a “March Miracle.” The odds are not good for a repeat of 1991. 2014 will be significantly worse. The Final SWP allocation will be about one-third 1991’s Final SWP Allocation. As noted in this Monday’s (January 27, 2014) Wall Street Journal editorial, “the chickens have come home to roost” after decades of gridlock in California.