System reoperations during wet years helped Alta Irrigation District navigate recent dry year

Kings River runoff during the just-concluding water year may have been limited by deepening drought conditions to just over half of average but new operating procedures, implemented in 2017 allowed Alta Irrigation District to deliver more water when compared to operations during previous wet years, which helped lessen impacts during this dry year.

Dinuba-based Alta, which serves eastern Fresno County, northern Tulare County (east and south of the Kings River) and a slice of western Kings County, was able to divert about 87,000 acre-feet of water during the summer season.

“Below average water years are not unique to the District and our history is pockmarked with single year and multi-year below average runoff events but this dry year demonstrates the importance of reoperations during wet years,” said the District’s General Manager, Chad Wegley.

The 2019-20 water year concluded September 30 and the Kings River’s full natural flow (as if there were no dams) is expected to be just 53% of average, according to the Kings River Water Association.

Looking back through the past decade’s many drought years, Wegley noted that the 2013-15 water years included the driest single- and three-year periods on record (see table below).

Summary of Water Run Operations During Driest Three-Year Period

Water YearVolume Diverted from Kings RiverDuration of Water Run
20150 acre-feet0 days
201425,800 acre-feet27 days
201335,700 acre-feet33 days

 

“That dry period is a stark reminder why improved operations implemented during wet years such as 2017 and 2019 were so important to water management in this area,” said Wegley.

In 2017, Alta set a record for its longest water run, 216 days, in half a century, for a total diversion of nearly 250,000 acre-feet. Not to be outdone, the District then diverted about 275,000 acre-feet in 2019 from the Kings River– fifth largest diversion since completion of Pine Flat Dam in 1954 and the second longest water run in half a century at 206 days.  While Alta’s General Manager Chad Wegley only has four years at the helm, his vision brought record setting water runs and headgate diversions in half of those years.

“Collectively, reoperation of facilities has allowed the District to divert about an additional 100,000 acre-feet above previous operations for similar water years,” Wegley said. “That is equal to 10% of Pine Flat Reservoir’s capacity.”

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