Pure Water Oceanside

Challenge

For decades, the City of Oceanside relied on imported water for more than 85% of its supply to its customers, with less than 15% coming from local supplies in the Mission Ground Water Basin and a 0.7-mgd Recycled Water Facility. Since the turn of the century, the City has been seeking ways to reduce their reliance on imported supplies, while also looking to create a sustainable local water supply in the Mission Basin, which has declined due to overuse.

To achieve these goals and create a more reliable local supply, the City retained Geoscience to conduct a phased evaluation to characterize the Mission Basin and study the feasibility of Groundwater Storage and Recovery projects in the Lower San Luis Rey River Valley in northern San Diego County, California. With the findings suggesting the potential for a conjunctive-use storage project in the Mission Basin (MGB), a geohydrological groundwater model (Mission Basin Ground Water Model) was redeveloped and updated using these results.

Geoscience Solution

Our team was then tasked with investigating groundwater replenishment reuse projects (GRRP) using treated wastewater from the City’s SLRWRF that would otherwise be discharged to the ocean. A series of groundwater analyses were conducted, technical and regulatory issues were analyzed, advanced wastewater treatment methods were identified, and groundwater recharge project options were developed.

The studies concluded that up to approximately 5,000 AFY of recycled water could be recharged into the Basin. Based on these findings, the City and our team moved forward with the development of an indirect potable reuse (IPR) groundwater augmentation project known as Pure Water Oceanside and expanding the City’s existing Title 22 tertiary recycled water distribution system.

Recycled water undergoes advanced water treatment (AWT) to produce the recycled water used for both injection and spreading. The facility will facilitate upwards of 3 mgd of recharge to the MGB through use of three (3) injections wells, with room to expand this amount to 4.5 mgd in the future. Facilities constructed included an AWT facility that produces up to 3 mgd capacity of advanced treated recycled water, the three injection wells, a conveyance pipeline to the injection wells, and three clustered monitoring wells.

Customer results

The Pure Water Oceanside project will benefit the City of Oceanside by producing a local, drought-proof water supply, ultimately reducing the City ‘s reliance on a less stable and more costly imported water supply. The project will also increase local, sustainable water supplies and Improve groundwater resources by supplying Mission Basin with an additional 3,360 AFY (3 mgd) of high-quality FAT water that will improve overall water quality in the aquifer and relieve over-pumping conditions.

In addition, Pure Water Oceanside will benefit the City financially, providing the ability to maintain lower future water costs by producing a local water supply through reuse, while also enabling the City to enhance its resiliency during droughts and climate emergencies, thereby assisting in the region’s ability to meet emergency storage objectives.

During the planning phases of Pure Water Oceanside, our team conducted an unprecedented Pathogen Removal Study, which examined the effectiveness of specific treatment steps taken to remove and inactivate pathogens from treated wastewater. The study was recognized during the Obama Administration’s White House Water Summit during World Water Day 2016 as one of many projects working on cross-cutting, creative solutions to solving the water problems of today.