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The Pleasanton City Council received an update from staff last week on the different water supply alternatives to address the contaminated water inside city-operated wells.
Council members were asked to weigh in and provide input on the different alternatives, none of which have been ruled out as the update was only the first out of a three-stage process before staff come up with a final recommendation on which alternative would be best for the city.
“We always must think about the health and safety of our residents,” Mayor Karla Brown said at the Feb. 21 meeting. “We need clean, safe water going into the homes of our residents and that’s our responsibility.”
In 2019, the city had shut down one of its three city-maintained wells after discovering PFAS, technically known as per- and polyfluoroalkyl substances. Staff then found the long-lasting chemicals in the other two groundwater supply facilities, resulting in staff having to shut down the other two wells last year.
These wells supply approximately 20% of the city’s annual water supply, with the remaining annual water supply being purchased from the Zone 7 Water Agency.
In order to address the widely used chemicals, which break down very slowly over time, staff had previously recommended approving a PFAS treatment and wells rehabilitation project. The scope of work for the project was to treat and rehabilitate wells 5, 6 and 8 in Pleasanton and to create a new centralized treatment facility for PFAS treatment, disinfection and fluoridation.
But on Sept. 6, the City Council pushed pause on the project and asked staff to evaluate other alternatives due to a $46 million price tag on the original project.
For the time being, staff reiterated that 100% of the city’s water will be purchased through Zone 7 while these alternatives that were presented to the council will focus on long-term solutions to the contaminated groundwater.
A Water Ad Hoc Subcommittee, made up of Mayor Brown and Councilmember Jeff Nibert, has been meeting every month since last October with consultant agency Brown and Caldwell, an engineering and construction firm focused on water and environmental sectors, to provide feedback and direction.
Last week’s meeting was the first quarterly update where staff and representatives from Brown and Caldwell presented data they collected from the city and from the Zone 7’s groundwater model to develop the list of water supply alternatives.
Some of the alternatives on the list include modified treatment only for Well 8; building a new well on the west part of the city outside of PFAS plume; having Zone 7 pump from the existing wells or purchasing 100% of the city’s water from the agency; constructing a joint, regional treatment facility with Zone 7; or local alternative supplies such as desalination.
Most of the feedback from the council was based on a lot of hypothetical scenarios as again, it was still early in the overall process of identifying different alternatives.
“We don’t want to toss away any alternative at this stage,” Nibert said. “We’re very early in the stage. The logical progression of activities at this stage is more like a brainstorming activity or was like a brainstorming activity.”
However, some of the main points brought up by councilmembers were on combining different alternatives, taking into account future housing development when talking about the groundwater supply and long-term solutions for using less water overall.
“Please consider the growth factor with primarily the residential growth that will happen in the future,” Councilmember Valerie Arkin said. “We want to make sure we’re going to be able to address that in the future.”
Daniel Repp, managing director of utility and environmental services for the city, said that those planning efforts are already underway.
“We just finished getting information from our planning department on the final future conditions,” Repp said. “We’re modeling that right now to understand what kind of demand that will put on our systems. We work with Zone 7 on that analysis again, because they need to know what to get because they’re the regional water supplier.
“This project is only looking at the 3,500 (acre) feet,” Repp added. “Whatever future demands, layers on top of that.”
Some of the water-saving efforts that Arkin also wanted to highlight as things to work on include recycled water lines that are located throughout the city, which supply recycled water to areas like Ken Mercer Sports Park and lawn conversion rebate programs where the city pays residents to convert their lawns from grass to eco-friendly lawns that use less water.
“People still do like the grass and there’s still a lot of grass out there so I think we need to continue looking at that as well as the recycled purple pipe,” Arkin said. “Those are a few things there that I think are definitely things we still need to continually look at.”
Vice Mayor Jack Balch took it a step further in saying that staff should look into the turf throughout the city, nonfunctional medians and future roadways or rehabilitating existing ones.
“The reality is climate change is real and we probably are going to need to look more like a Palm Springs type of look slightly in our medians, rather than a one foot wide strip that we try to maintain at extensive costs,” Balch said. “So I think we just need to continue to think long term and it sounds like we are.”
One point Repp emphasized was that the PFAS treatment and well rehab project will still be considered as a baseline alternative that the other options will be evaluated against.
Staff also presented a set of evaluation criteria that will be used to determine what alternative would be best to replace the 3,500 acre-feet of groundwater supply that the city has relied on in the past.
According to Katie Ruby, water resources engineer at Brown and Caldwell, the criteria will be used to score various water supply alternatives and analyze trade offs that help with prioritization and alternatives selection.
“We want to confirm the criteria before we have particular alternatives in mind because we don’t want to bias the result by predetermining what we think the outcome should be,” Ruby said.
She said that the criteria is being framed around benefits to the city, with cost considered separately as a constraint and that once the alternatives are further developed, they will apply the weighted criteria to evaluate and prioritize alternatives.
While staff are not at the stage where they rule anything out, there was some general consensus between Councilmember Julie Testa and Mayor Brown on blending and diluting the water to achieve low levels of contaminated water.
“Blending is just saying a little bit of poison isn’t as bad as a lot of poison. Well, they’re both bad poison,” Brown said. “While the maximum contamination limits have been discovered and are being finalized by our legislators, it’s not a trustable water source. It’s really not a good option.”
Testa mentioned that her favorite option as of now is the modified treatment for Well 8.
Nibert also mentioned that while he didn’t have a particular favorite, his least favorite option was desalination, which is a process that takes away mineral components from saline water.
“It’s obvious that some of these items, for example, desalination, are very expensive,” Nibert said. “We know that and it will fall out just as was mentioned at a later stage in the process. But we need to follow the process.”
“It would not surprise me that the ultimate recommendation or several recommendations end up being a combination of all of perhaps all of these items,” Nibert added.
Following last week’s update, staff will begin the next steps which was set to include an initial screening of the alternatives at this week’s Water Ad Hoc Subcommittee meeting, development of cost estimates and evaluating of the shortlisted alternatives based on multiple evaluation criteria.
