Regional Groundwater Facilities Project
Background
Zone 7 Water Agency (Zone 7) is a water wholesaler who procures water from the California Department of Water Resources (DWR) and produces water from its regional groundwater wells to sell to the City of Pleasanton (City) and other Tri-Valley water retailers for distribution to its customers. In addition to buying water from Zone 7, the City also has local groundwater wells that supply up to 3,500 acre-feet per year of water (known as City’s groundwater production quota or GPQ), which represents approximately 20 to 25 percent of the City’s total water supply needs.
Per- and polyfluoroalkyl substances (PFAS) have recently been detected above regulatory requirements in portions of the Livermore-Amador Valley Groundwater Basin. This detection has impacted some of Zone 7’s regional groundwater wells (see Zone 7 PFAS Information for details) and all of the City’s groundwater wells (see Pleasanton Water for details). On October 17, 2023, the City Council approved proceeding with the planning of new groundwater wells within the Bernal subbasin (which is believed to be outside the existing PFAS plume based on Zone 7 testing and groundwater modeling) to recover the use of its GPQ. As part of the planning efforts, the City Council placed an emphasis on evaluating the feasibility of collaboration with Zone 7. In February 2024, Zone 7 and City staff completed a process that outlined the terms of collaboration for a joint project titled the Regional Groundwater Facilities Project (Project).
Overview
The Project is envisioned to include the following elements:- Construction of new groundwater well(s) in the Bernal subbasin with the goal to increase Zone 7’s groundwater production capacity and drought resiliency for the overall Tri-Valley region, recover the City’s GPQ, and produce water supply that meets and exceeds all State and federal water quality standards.
- Connection of the new groundwater well(s) to Zone 7’s water supply system and upgrade of the existing Zone 7 Hopyard Treatment Facility to treat the water.
- Delivery of the City’s GPQ via the Zone 7 water supply system (as opposed to the current configuration of direct delivery from dedicated City wells).
- Phase I – Feasibility: This phase will evaluate the feasibility of the Project and has a target completion date of spring 2025.
- Phase II – Design and Construction: If the City and Zone 7 find the Project to be feasible, this phase will include the design and construction of improvements in accordance with Phase I recommendations. The target completion date for this phase is the end of 2028.
- Phase III – Operation and Maintenance: This phase would start after completion of Phase II and when required permits to operate are in place.
Upcoming Activities
The Project is currently in Phase I. Current and upcoming activities include the following:
- City and Zone 7 Agreement for Phase I: The City and Zone 7 are currently preparing an agreement to perform Phase I of the Project. The anticipated schedule for governing body consideration and approval of the agreement is the June 18, 2024, City Council meeting and the July 17, 2024, Zone 7 Board Meeting.
- Well Siting Evaluation: The purpose of this evaluation is to identify potential locations for the installation of new groundwater wells based on factors such as historical information on anticipated yield and water quality, proximity to the PFAS plume, proximity to the Zone 7 water supply system, land rights, and suitability for operation and maintenance activities. Preliminary activities to date have identified the potential locations shown in the figure below. Additional evaluation is ongoing, with a target completion date of summer 2024.
- Exploratory Test Drilling: Upon completion of the well siting evaluation, exploratory test drilling will be performed at select locations. Exploratory test drilling includes the use of drill rigs and supporting equipment (such as that pictured below) to install monitoring wells that allows for the collection of information such as water yield and quality. This information is critical in determining the overall feasibility of the Project. Upon completion of exploratory test drilling, the belowground monitoring well remains with only a well box visible at the surface. Exploratory test drilling is anticipated to occur during the summer and fall of 2024. Additional information will be provided once specific locations are selected
Additional Information
Project related information is provided below:
- On June 18, 2024, the City Council approved an agreement to partner with the Zone 7 Water Agency on Phase 1 (Feasibility) of constructing two new wells as part of a Regional Groundwater Facilities Project.
- On May 7, 2024, the City Council approved the execution of a $19 million water revenue bond to assist in financing improvements to the City’s water system, including Phase 1 of the Regional Groundwater Facilities Project.
- View the October 17, 2023 City Council Water Supply Alternative Agenda Report
Should you have any questions or comments regarding the Project, please contact the Public Works Department at (925) 931-5500.
Water Project FAQs
What is the Regional Groundwater Facilities Project?
Why is this project needed?
What are groundwater wells and how do they work?
Groundwater wells are vertical shafts drilled into the ground to access underground water sources, known as aquifers. Wells are typically created by drilling a hole into the ground and installing a pipe (casing) with a screen at the bottom to allow water in while keeping soil and debris out. Most modern wells use electric pumps to bring water to the surface.
With the Regional Groundwater Facilities Project, new wells are being developed to replace existing wells affected by PFAS contamination, ensuring a continued supply of safe drinking water for Pleasanton residents.
What are PFAS
PFAS (Per- and Polyfluoroalkyl Substances) are a large group of synthetic chemicals designed to resist heat, water and oil. PFAS are used in a wide range of industrial and consumer products such as fire-fighting foams, stain- and water-resistant clothing, carpets, cleaning products, non-stick cookware and food packaging.
PFAS have been found in air, soil and water around the world, and are persistent in the environment. They can accumulate in the human body over time, and are toxic at relatively low concentrations. Scientific studies have shown that exposure to some PFAS in the environment may be linked to harmful health effects in humans and animals. Although certain PFAS are no longer manufactured in the U.S., these chemicals are still produced internationally and imported into the U.S. in consumer goods.
For additional information about PFAS, see the Pleasanton Water webpage.
What is the timeline for this project?
The project is separated into three phases:
- Phase I – Feasibility: Evaluation of the feasibility of the joint project with a target completion date of spring 2025.
- Phase II – Design and Construction: If the City and Zone 7 find the Project to be feasible, Phase II will include the design and construction in accordance with Phase I recommendations. The target completion date for this phase is the end of 2028.
- Phase III – Operation and Maintenance: This phase would start after completion of Phase II and when required permits to operate are in place.
Where are the potential well sites being evaluated?
- Pleasanton Tennis and Community Park (5801 Valley Ave.)
- Del Prado Park (5196 Golden Rd.)
- Hansen Park (5697 Black Ave.)
How were these sites selected?
The three sites were selected for the following reasons:
- City-owned, allowing for easier implementation
- Close proximity to Zone 7’s Hopyard Treatment Facility for cost efficiency
- Sufficient space for construction and operation
- Located outside of the assumed limits of PFAS groundwater contamination
What will happen at these test sites?
Drilling rigs will be set up (in an approximately 100 ft x 75 ft area) to conduct exploratory test drilling at each site for 4 to 8 weeks. Samples collected from exploratory test drilling will be used to analyze groundwater quality and production capabilities.
How will construction impacts like noise be managed?
All construction activities must follow City of Pleasanton noise regulations. Measures like sound walls will be used as needed during temporary well testing. Permanent wells will be designed with measures such as submersible pumps and enclosures to minimize operational noise.
How can I stay informed or provide input?
The City of Pleasanton is committed to keeping the community updated throughout the project.
This project-specific webpage will contain the project background, the latest updates, and information about relevant community outreach events. Residents can also sign up for email updates, participate in upcoming community meetings, and monitor the City’s social media pages to stay informed on the project.
To provide input contact the Public Works Department via our contact form or (925) 931-5500.