During what has so far been one of the driest water years on record for the Turlock Irrigation District, the water agency’s Board of Directors on Tuesday received information on just how much — or how little — irrigation water local farmers could potentially receive this season.
“Sadly, this year is shaping up to be a very dry year as you guys have seen...it is the sixth-driest year on record to date, so there is nothing that we can do about that,” TID Assistant General Manager of Water Resources Tou Her said. “So far, mother nature has played its card and it is dry so far. Considering that it follows a previously dry year, it makes this workshop very necessary and prudent.”
The irrigation workshop provided Directors with preliminary information concerning the fast-approaching irrigation season, based on precipitation and snowpack data up to Tuesday. According to Her, TID is anticipating two more important data sets which will give the organization an even better idea of how much water will be available for growers: The March snowpack survey, which will be available next week, and a planned airborne snow survey set for later this week.
The information will be vital, given the fact that the Tuolumne snowpack is already measuring at just 55.6% of the historical average for the date. The snowpack was bolstered by recent storms, but TID Hydrology Utility Analyst Olivia Cramer said that close to zero rainfall is expected in the region in the next eight to 16 days.
“We’ll see how the next forecast cycle goes and if we can build up anymore snowpack, but likely we’re not going to be hitting that normal (data point),” Cramer said.
While a resolution has not yet been presented to Directors for approval regarding the irrigation cap, preliminary information led analysts to suggest a 34-inch allotment during the workshop. Since the 2020-2021 water year is the second consecutive dry year, analysts looked to the last drought from 2012 to 2016 in order to decide how much water should be provided to farmers.
In 2012, the Tuolumne River Watershed received 48% of the historical average in rainfall and growers were allotted 40 inches. In 2020, the irrigation cap was set at 42 inches following a 51% water year. In order to decide how much irrigation water should be provided this season, TID looked at the 2013 allotment, which was also a second consecutive dry year like the region is currently experiencing.
Expecting average conditions, the water year could end up close to the 2013 value of 59%, Cramer said. An irrigation cap of 34 inches was set then, and is the allotment which was also presented on Tuesday for this season.
The current water year, which began in September, has seen the watershed receive 14.19 inches of precipitation so far, or 60.8% of the historical average. Should dry conditions persist, the water year as a whole could end up sitting at 21 inches in total.
The snowpack is better off than it was at this time last year, however, Cramer informed the Directors that numbers were about 15% lower at this point in 2020.
TID Water Distribution Department Manager Mike Kavarian stated that the potential 34-inch allotment for farmers was just a starting point based on current data. It’s anticipated that the irrigation season could start March 18 and last through Oct. 27, and water prices would run at the dry year rate of $68 per acre foot.
“At the highest level, I would just say I am very supportive of a conservative allocation that lays the groundwork for the potential of a long-term drought,” Director Michael Frantz said. “...I think it's in keeping with our past practice of incrementally reducing water availability as we work our way into potentially a multi-year drought situation.”
The official irrigation cap and season will be set during a future TID Board of Directors meeting.