You are the owner of this article.

Tracy considers expanding use of recycled wastewater

  • 0
  • 5 min to read

In the search for new water supplies for a growing city, Tracy could turn to a supply that it already has but hasn’t used to its full potential.

The city’s wastewater treatment plant will soon be capable of turning out 21 million gallons a day of recycled water. Most of that water goes into Old River, but it is also used to water parks and city-owned landscaping around town.

Soon, the city could use start trading its extra treated wastewater for water that could contribute to the municipal water supply.

The first of a pair of reports that the Tracy City Council reviewed on Tuesday spells out the limits of Tracy’s existing water supplies — the Delta-Mendota Canal, South San Joaquin Irrigation District and city groundwater wells — and names recycled water as a future source.

The second report proposes that the city work with a consultant to determine just how much money the recycled water from the wastewater treatment plant could be worth if the city wanted to sell it to other users, including farms and irrigation districts.

Elizabeth Drayer, the project manager from West Yost Associates for the city’s Water System Master Plan Update, told the council that the latest update of that plan in 2012 anticipated that the city’s water supplies would be sufficient for buildout of the city’s general plan, with 30 years of development to include Tracy Hills and the International Park of Commerce, formerly known as Cordes Ranch.

But there have been severe droughts since that plan was created, and that requires the city to rethink the reliability of its water sources. Allocations from the federal Central Valley Project by way of the Delta-Mendota Canal are subject to cutbacks, and the South San Joaquin Irrigation District’s supplies from Woodward Reservoir near Oakdale may also be subject to cutbacks soon.

Drayer noted that Tracy’s water use peaked in 2007 at just over 19,000 acre-feet for the year. Though the city’s population has increased since then, more efficient use of water— including conservation measures in response to severe drought years in 2015-16 — has meant that the city hasn’t increased its overall use. Citywide use dipped to 14,000 acre-feet in 2015 and was just over 16,000 acre-feet in 2017.

Since 2005, most of that water has come from either the SSJID pipeline or the Delta-Mendota Canal, with very little reliance on groundwater, which was the city’s biggest source before 2005. Drayer told the council that the city now must plan for a growing population at the same time as its water supplies become less reliable.

Existing supplies add up to 26,588 acre-feet per year under ideal conditions, but in a single drought year the total dwindles to 18,751. That is still enough to serve the city’s potable water needs, but not by much. It won’t be nearly enough once the city’s water demands more than double in 30 years as foreseen by the general plan.

The state’s Bay-Delta Plan is also getting an update. The plan aims to improve the health of the ecosystems in the state’s waterways. That means keeping fresh water from the Sierra flowing down rivers — including the Stanislaus River, where the South San Joaquin Irrigation District gets its water — through the Delta and into the bay. That creates the potential that less water would be sent to municipal water systems.

“The South San Joaquin Irrigation District supply was thought to be a very reliable supply, and it was a reliable supply through the drought years, but this new Bay-Delta Plan could change that in the future,” Drayer said, noting that the supply could be cut by 25% in dry years, and by more than 60% during extreme droughts.

For now, the city has plenty of water, even in dry years, Drayer reported, but those supplies will eventually fall short of demand.

“To close that gap between existing supplies and what we need in the future, we’re looking at recycled water as our primary way of closing that gap,” she told the council.

The first use for recycled water is irrigation, which the city is already doing in parks and landscaped areas, but recycled water could also play a key role in the city’s efforts to meet its future drinking water demands.

The treated wastewater would not go into the municipal water supply, but it could be exchanged for water that comes from the Delta, and then sent south to irrigate farm fields served by the Delta-Mendota Canal.

“We are proposing to negotiate an exchange arrangement with the state to be able to discharge treated recycled water to the Delta Mendota Canal, and it would be discharged just downstream from the John Jones Water Treatment Plant,” Drayer said.

The city, in exchange, would collect water upstream from the plant.

“For the amount of water that gets discharged into the Delta-Mendota Canal, the city would be able to take a like amount of water from the Delta-Mendota Canal and treat that at the city’s treatment plant, and be able to use that for a potable supply,” she said.

The council isn’t taking action on the matter now, but it will have to consider the new realities of the state’s water supplies moving forward.

“We had this very lengthy discussion years ago when we were approving Tracy Hills and I was concerned about, do we have enough water?” Councilwoman Rhodesia Ransom said. “I was reassured that all of these different resources were available, so when we approved projects we knew that the water would be available.”

She added that, after hearing the report, she’s less confident in the city’s ability to support future development.

“It’s like, the supply is strong. We have a strong portfolio of available sources, but then I feel like there’s this huge risk factor that maybe we’re really not talking about,” Ransom said. “We were using SSJID and now you’re telling us that may not be as available, depending on the drought years.”

Mayor Robert Rickman said previous councils did their job well by making sure a reliable water system was in place, but the nature of California water politics is that the state has to constantly look for new ways to capture limited resources. In particular, he questioned why more dams and reservoirs are not being built to capture Sierra runoff.

“It just goes to show you, this is the frustrating part. This year, last year, we have trillions, trillions of gallons of fresh water, rain and snow, and it’s just being sent right down to the ocean,” Rickman said. “That water is not being used, though what I believe, in 2014 the people in California wanted more storage and we still haven’t had that storage. Some of these problems that cities are seeing could be alleviated if the state of California would do what needs to be done, which is to put more water storage out there.”

The council then heard from Private Public Infrastructure Group LLC., of El Dorado Hills, a company that proposes to build parts of Tracy’s recycled water infrastructure, such as treatment, storage and pipelines, in return for rights to sell that water in partnership with the city.

A report by Assistant City Manager Andrew Malik and Utilities Director Kul Sharma notes that direct uses for recycled water include irrigation of parks and landscaping. If treated further through methods like reverse osmosis, recycled water could be reclaimed as drinking water.

The idea of a water exchange also came up in the discussion with PPIG, again with the idea of putting recycled water into the Delta-Mendota Canal downstream from the city’s water treatment plant, effectively exchanging it for water upstream from the plant. The city could continue to treat that upstream water and add it to the municipal water supply.

The council unanimously agreed to enter into an exclusive negotiating rights agreement with PPIG. The company plans to start with a feasibility study to determine if there is money to be made by selling water to farms or other water agencies downstream from Tracy along the Delta-Mendota Canal.

Jim Miller, general manager of PPIG, told the council that his company has been researching the idea for three years and now wants to see if it works financially before Tracy needs that water to supplement its existing water supplies.

“The idea behind the project is to search whether or not it’s conceivable to monetize that stream for the city, create a revenue stream for the city. That water is not being used right now and there’s nothing being done with it,” he said.

Rickman noted that, even with the exclusive negotiating rights agreement, PPIG has no guarantee that it will actually win a contract to build recycled water infrastructure or sell the city’s recycled water.

City Manager Jenny Haruyama added that, should PPIG come up with a study confirming that recycled water is a marketable commodity, the city would still call for bids to see if other companies were qualified to partner with the city to sell that water.

Contact Bob Brownne at brownne@tracypress.com or call 209-830-4227.

(0) comments

Welcome to the discussion.

Keep it Clean. Please avoid obscene, vulgar, lewd, racist or sexually-oriented language.
PLEASE TURN OFF YOUR CAPS LOCK.
Don't Threaten. Threats of harming another person will not be tolerated.
Be Truthful. Don't knowingly lie about anyone or anything.
Be Nice. No racism, sexism or any sort of -ism that is degrading to another person.
Be Proactive. Use the 'Report' link on each comment to let us know of abusive posts.
Share with Us. We'd love to hear eyewitness accounts, the history behind an article.