The acres of almond, walnut and other crops surrounding Turlock have benefitted immensely from the surplus of irrigation water provided to them this year, with such conditions coming as a result of one of the wettest years on record for the Tuolumne River Watershed.
After five years of severe drought conditions, the 2017 irrigation season kicked things off on March 30 with an ample supply of water, thanks to the 189 percent above average precipitation the watershed had received as of March 21. Turlock Irrigation District was able to provide 48 inches of water per acre for the 2017 season, will which conclude Nov. 1, and replenishment water for areas outside TID’s service area was also made available for the first time since 2011.
This past precipitation year, which ended Aug. 31, was the second-wettest ever recorded in terms of precipitation, and has been the wettest year on record when it comes to runoff, according to TID Utility Analyst Jason Carkeet. The year yielded 63.67 inches, compared to 39.42 inches the previous year, and has supplied a runoff to date of 4.86 million acre feet. Last year, the total runoff was 1.82 million acre feet.
The 48-inch cap water allotment approved by the TID Board of Directors in March was quite an improvement from that of the 2016 irrigation season, which was set at 36 inches, and a breath of fresh air compared to the disheartening 18-inch cap water allotment set during the 2015 irrigation season.
Derek Spycher, who grows almonds in Ballico, said that during the low cap water allotment years, he and his father installed drip irrigation systems in their orchards to help conserve what little irrigation water they received.
“It wasn’t as much about saving as the fact that we only had so much water, we had to make it go as far as it could,” said Spycher.
This year, however, TID customers were encouraged to flood irrigate in order to help recharge the area’s groundwater. While that encouragement is a sign of improved water conditions, Spycher said the biggest benefit he saw as a result of the wet year was accessibility to canal water for use in a block of his crop, rather than the usual well water that was pumped for irrigation use in previous dry years.
“That canal water is only made accessible during high water years,” said Spycher. “Canal water is preferred over well water because it’s cheaper, and it reduces salt damage better.”
Other farmers have been enjoying the significantly above-average water supply, and coupled with a hot summer, there has been about a 21 percent increase in water released from Turlock Lake for irrigation purposes, said TID Public Information Officer Calvin Curtin, with a total of 422,509 acre feet of water released through the end of September.
Peak releases from Turlock Lake occurred during some of the hottest months, from the end of June to late August, with demand for irrigation water increasing by about 10 to 15 percent during hotter days. Customers often place multiple orders for several parcels numerous times a month due to higher than normal temperatures, said Mike Kavarian, Water Distribution Department Manager.
In July, there were 13,684 water orders received, which was the highest number in several decades. August was also a particularly hot month, and 11,473 water orders were received, compared to 7,000 in 2016. That number decreased by nearly 50 percent in September as temperatures began to fall, with 6,643 water orders taken throughout the month.
Whether or not the Tuolumne River Watershed will receive another ample supply of precipitation this 2017-2018 water year is still to be seen, said Carkeet, as many factors combine to affect climate in the area, including the El Niño Southern Oscillation, the Madden-Julian Oscillation, the Pacific Decadel Oscillation and the Indian Ocean Dipole – all of which include fluctuating temperatures in either the Pacific, the tropical atmosphere or western Indian Ocean.
“It gets pretty complicated, which is why climate forecasts typically provide a range of probability for a given condition rather than being of a deterministic nature,” said Carkeet.
According to the National Weather Service, the current outlook calls for equal chances of above normal, normal and below normal precipitation in our area. Carkeet added that the strength of La Niña – which was weak last year, contributing to one of the wettest winters on record – could help determine how wet or dry the coming winter could be.
“Right now, it’s just a La Niña watch,” said Carkeet. “There are equal chances either way.”