Reservoirs sit well above average in late summer months
Full reservoirs spell good news for farmers and fish as noted in the Friant Water Authorities report to contractors
By John Lindt
Sierra 2 the Sea news service
CALIFORNIA – The driest years on record continue to get farther and farther in the rearview mirror as reservoirs fill to the brim.
California’s water masters have socked away a well-above average supply of snowmelt in the state’s reservoirs this summer after a wet year soaked most of the state. The Central Valley Project’s lakes north of the Delta are nicely above normal with total storage at 6,900 thousand acre feet (TAF). Trinity, Shasta, and Folsom reservoirs are at 134%, 134%, and 138% of their 15-year average storages respectively.
The carryover is a wonderful insurance policy as California ponders if the 2019/20 water year could deliver another wet one or by contrast, a duster.
Predictions for upcoming winter are just starting to percolate but observers note that they are famously inaccurate. Last year few predicted a record snowfall year for the West or floods in Midwest. As it turned out it was much colder and wetter than predicted in the West and above-average snowfall in most locations. So because we store the water in Sierra and foothill reservoirs and in Valley groundwater basins – we have an unusual cushion going into the fall/winter months for 2020.
Good for farm and fish
Full reservoirs are good news for both farm and fish for a change as noted in a report to Friant Water Authority contractors last week.
“Cold-water pool volume in Lake Shasta is well above normal and this puts Reclamation in an advantageous situation for managing Sacramento River temperatures in the late summer and early fall. In order to benefit this year’s blockbuster winter-run salmon return, Reclamation will be operating to a reduced temperature target of 52.8° F on the Sacramento River at Clear Creek through the end of October. The prior target was 53.5° F This will be accomplished by reducing release temperatures using the TCD, so will not affect carryover storage or water supply operations,” the report stated.
South of Delta reservoir storage are mostly higher than average as well with Pine Flat near Fresno standing at nearly 800,000 acre feet, or 174% of average for this time of year. Millerton is at 161% of average. Castaic, Santa Barbara’s water supply is 108% of average while Lake Nacimiento, San Luis Obispo’s water supply stands at 58% of capacity. The reservoir saw 16.6 inches of rain this past year compared to 9.7 in by this date the year before.
Kings River Water Association Water Master Steve Haugen says carryover was a lifesaver in 2018 after a wet year in 2017 followed by a dry year. ”It allowed farmers to deliver an average amount that season” he says. Pine Flat was built with carryover capacity for just such a situation. Unlike Pine Flat the next reservoir down state – Lake Kaweah needs to vacate each year for flood control purposes, so there is little carryover.
Kaweah’s carryover has to happen at the Valley floor level in scores of groundwater basins.
No record in California
NOAA reported recently that July 2019 was Earth’s hottest month in 140 years of record keeping. The agency said last week that global average temperatures across all land and ocean surfaces in July were the highest of any month in its database, which extends back to 1880.
But California dodged a bullet in July with about average temps and not a bunch of terrible fires. NWS Hanford says Fresno had 30 days above 100 F in July 19 compared to an average of 36. Bakersfield had 26 100F days compared to an average of 33 and a record of 53 in 2017.
Despite the lack of confidence in predictions, the NOAA Climate Prediction Center may be the best we have. The agency just published(Aug 15) their three-month index for Jan-March 2020 and it looks dry for California, particularly the mid-state with a 40% chance of lower than average rainfall in the period. This is typically the wettest part of the water year.
The upshot: better keep squirreling away that water.