This report/commentary prepared by hydrologist Robert Shibatani.

With growing speculation, people are starting to express concern over this water year’s supply prospects. A lack of rainfall, together with a rapidly depleting snowpack are normally cause for concern. Fortunately, our water system is based on reservoir carryover storage, which is exactly what these reservoirs were designed to do.

As of the end of February, there was 8.44 million acre-feet (MAF) in north CVP storage (representing over 74% of total system capacity). North CVP storage is 113% of the 15-year average, having dropped 1% over this past month. Oroville Reservoir is at 106% of its 15-year average. Shasta, Trinity, and New Melones reservoirs, the “Big 3”, are each storing 3.5, 2.0 and 1.9 MAF, respectively, representing 111%, 126%, and 127% of their 15-year average storage quantities for this date.

Precipitation totals are low across the State. The southern Cascades have received about half of what they typically receive. The northern and central Sierra Nevada are faring a little better, having received about 65% of their average. Correspondingly, accumulated inflows from their source area watersheds have been below normal. Although for Shasta and New Melones, the accumulated reservoir inflows are about 70% of their 15-year averages. Keswick, Oroville, and Goodwin are all making releases above their 15-year averages.

As I stated a few days ago, as long as the CVP/SWP don’t go all “environmental” on us and start making releases for water quality/fisheries without due consideration of consumptive M&I and Ag demands, there should be no problem. Do we need a Miracle March? No. So long as again, the CVP/SWP don’t go overboard with environmental releases. Would a Miracle March help? Sure, it would. But again, too much rain would show the weakness of the system in its insufficient storage capacity. Much of the precipitation would likely have to be “spilled”.

March will be key, the ball is literally in the federal/State hands, let’s hope they don’t squander it.

Prepared by Robert Shibatani

Robert Shibatani, a physical hydrologist with over 35-years combined academic, legal, consulting and water advisory expertise, is an international expert witness on reservoir-operations, climate change hydrology, commercial flood damage litigation, and water supply development.  He is Managing Partner for The SHIBATANI GROUP International, a division of The SHIBATANI GROUP Inc. and resides in Sacramento, California.

Please note:  The views expressed in this report are those of the authors and should not be attributed to Maven’s Notebook.


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