UC Davis experts evaluate the water year, so far


From the UC Davis Center for Watershed Sciences

January 2016 (was) much wetter than the previous Januaries during this drought. Precipitation is modestly above average, as is snowpack, and climatic conditions remain promising. The largest reservoirs are mostly fuller than a year ago, although not nearly to average conditions for this time of year. Groundwater is likely to be recharging, as it should this time of year in most places, but we still sit atop a large hole.

California remains in a drought. Precipitation and snowpack are now mostly above average for this time of the water year (the 2016 Water Year began October 1, 2015). So far, El Nino is delivering a somewhat above normal water year. But, overall 2016 drought conditions are likely to remain unclear until March.

The California Department of Water Resources’ California Data Exchange Center (CDEC) does a great job assembling data that give insights on water conditions. They update this every day at http://cdec.water.ca.gov.

Here are some recent highlights, with links.

Reservoir and Groundwater Storage Conditions

Most major reservoirs in California have more storage that at this time last year, but still have only about 60% of historical average for this time of year. Folsom Lake is now at 100% of average for this time of year, rising from a record-low level in November. But California’s reservoir storage remains about 7 maf (about 7 full Folsom reservoirs) less than average for this time of year.

reservoir

Groundwater statewide is harder to assess, but is doubtless making some recovery from last year’s levels. It still has a long way to recover from the drought in many places.

The drought so far has depleted total storage in California by about 22 maf cumulatively or nearly a year’s worth of water use in agriculture. Soil moisture conditions were also unusually dry following 2015, diverting and delaying some runoff from early storms.

Precipitation and Snowpack

7791

December and January storms have helped, with precipitation and snowpack mostly a bit above average for this time of year. We seem to have overcome the Curse of Zero Januaries; January precipitations for the last three years was nearly zero. This January precipitation in the Northern Sierras is above average and exceeds the sum of all January precipitation for the last five years!

Snowpack in California is mostly above average for this time of year and already greatly exceeds last year’s snow accumulations. There is a ski season.

7792

Is it El Nino yet? Apparently, yes. But it is giving us slightly better than average conditions, which so far are much better than the last four years. No major floods yet. So far, the forecast for February looks good.

Snowpack:

Concluding thought

Steady, above average precipitation and a decent snowpack, so far. Much better than the last four years. Let’s hope it continues, but remain prepared for another drought year, or at least lingering drought effects even if conditions are modestly wet this year.

Wonks might be interested in UC Davis’ ongoing seminar series on drought impacts and policy (most Mondays at 4pm on the UC Davis campus). The public is welcome and videos are posted some days after each talk. Details at:https://watershed.ucdavis.edu/education/classes/california-water-policy-seminar-series-drought This Monday we’ll hear from Peter Moyle (UC Davis) and Jay Ziegler (TNC) on ecosystem impacts and management during the current drought.

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About Kevin

Mayor - City of Oakley, Data Center Manager of Mainframe Operations and Optimization – USS-POSCO INDUSTRIES, Co-Founder and Board Member - Friends of Oakley A Community Foundation, Advisory Board – Opportunity Junction, Commissioner - Contra Costa Transportation Authority, Board Member - Tri Delta Transit and Transplan
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