The old Hilmar water treatment facility could soon help strengthen local water conservation efforts made by the Turlock Irrigation District, as the district Board of Directors voted on Tuesday to spend $2.34 million to pick up the previously abandoned project in an effort to catch canal water currently spilling into the Merced River.
The TID Board of Directors voted 5-0 in favor of picking the project up again, nearly 15 years after it was first postponed. Project negotiations between the Hilmar County Water District and Turlock Irrigation District administrators are expected to begin soon, discussing the changes in state legislation and California’s ongoing drought which first led the water agencies to reexamine the project, also known as the Lateral 8 Total Channel Control Pilot Project, earlier this year.
Representing TID in property negotiations with the HCWD will be TID General Manager Casey Hashimoto or his designee, as the District begins taking steps toward establishing a regulating reservoir at the head of Lateral 8, near the end of the Highline Canal in Hilmar.
Currently owned by HCWD, the property directly north of the head of Lateral 8 contains an abandoned water treatment facility at the intersection of the two canals in addition to approximately 19 acres of farmland rented out by HCWD to the north and east of the facility. With the Merced River lying closely upstream from Lateral 8, TID has considered the property as being ideal for usage as a regulating reservoir as early as 1998.
Although an intertie was established between Lateral 9 and Lateral 7 in 1999, with conceptual plans to connect the pipeline to the existing basins of the abandoned water treatment plant, TID opted to indefinitely postpone the project due to financial reasons.
“At the time there was insufficient need to justify the expense of the project, so the concept had been filed for possible future use,” said TID Assistant General Manager of Water Resources Tou Her. “However, the current drought and recent state legislation resulted in a reexamination of the project in January of this year.”
Upon reexamination, research conducted by TID staff members, who also completed a survey of the existing facility, found that with various modifications to the interior, the abandoned plant could be operated as a cost effective regulating reservoir for the adjacent canals.
Once redeveloped and running, the regulating reservoir will operate by being gravity fed water from the Highline Canal when the canal is running higher flows than expected. It would then pump the stored water to Lateral 8 and Lateral 7 when canal flows downstream of the reservoir are lower than usual.
Such variations in the flows are a result of operational fluctuations on the canals and often more pronounced at the lower ends of TIDs canal system, in canals such as Lateral 8. According to TID, the operational increases in canal flow rates currently lead to spills out of the Highline Canal.
With the ongoing drought heavily impacting water supply levels throughout the state, many irrigation districts including TID have taken additional measures to prevent or recapture such spills. If developed, the regulating reservoir could significantly reduce spills out of the Highline Canal, capturing the water instead of losing it. Additionally, the reservoir would stabilize flows downstream by pumping to fill shortages in water supply caused by downward fluctuations, resulting in improved customer service, says TID.
“Given the reservoir’s current capacity limitations, and the amount of average yearly spill from the Highline Canal, the reservoir would save approximately 2,550 acre feet of water on average each year,” said Her.
Her also said that should the reservoir's operations live up to the District’s expectations, TID could possibly expand the reservoir to occupy the majority of the 26.1 acre property, increasing its holding capacity from 29 acre feet to 135 acre feet.
“This would boost the water savings to approximately 9,000 acre-feet on average each year and allow for more flexibility in downstream irrigation,” said Her.
Although the two water agencies are only entering property negotiations at this point in time, TID staff is estimating a cost of $2.34 million to purchase the 26 acres of land and modify the existing 7-acre water treatment facility.
Additionally, the Board of Directors voted on Tuesday to appropriate an additional $3.3 million to the 2014 Capital Budget to fully fund the entire project.