Morro Bay, CA – The City of Morro Bay recently completed a critical test for the recycled water component of its Water Reclamation Facility Program. With the recently completed construction of Injection Well No. 1, the City was able to perform an extended Injection Test. The results of the Injection Test, which included injection of potable water into the Morro Groundwater Basin via Injection Well No. 1 and monitoring of nearby groundwater conditions, will inform the design of the Indirect Potable Reuse (IPR) Recycled Water injection system. The test successfully demonstrated the ability to inject water into the basin to protect against seawater intrusion, augment groundwater supplies in storage, and improve groundwater quality. Next steps for IPR project will include the design, permitting and construction of the remaining injection wells and advanced purified recycled water pipelines. The advanced treatment facilities to produce the high-quality recycled water for injection into the groundwater basin are being completed and undergoing testing at the Water Resources Center.

The injection test was initiated on December 6, 2022, with a controlled flow rate of 95 gallons per minute (gpm) being conveyed into the well. The testing was conducted until January 4, 2023.  During the test, water levels in both the injection well and the nearby monitoring well were recorded on an hourly basis.  Water quality data were also tracked to (a) document the quality of the injected water and (b) determine the migration rate of the injected water from the injection well to the nearby monitoring well.  Water quality data collected from the monitoring well on December 20, 2022, confirmed the arrival of the injection water at that location, which allows the calculation of the migration rate thru the aquifer sediments. These data will be useful in both future project planning and for permit acquisition through the Regional Water Quality Control Board. Finally, a series of water quality samples are being collected following cessation of the test to evaluate if geochemical changes occurred within the aquifer following the introduction of the potable water source (State Water Project water).

The IPR component of the WRF Program provides the City with a new water supply that will be available regardless of future hydrologic conditions, including climate change, and enables the City to improve the resiliency of its water supply portfolio to mitigate against future droughts and State Water Project infrastructure failures. Having this local, resilient supply will provide water security for the City, reduce its reliance on Sacramento-San Joaquin Delta imports, and improve local groundwater quality.

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