SAN LUIS OBISPO -– Although the Central Coast experienced an intense storm system last week, the City of San Luis Obispo’s proactive preparation allowed for minimal disruptions to regular services. This was exemplified by the extraordinary measures taken by the City’s Water Resource Recovery Facility (WRRF), where a comprehensive upgrade to the facility—called SLO Water Plus—is currently underway while also maintaining full operational capacity.

SLO Water Plus is the City’s largest capital investment to date, totaling approximately $111 million in construction costs. Upon the project’s completion in 2024, the upgrades and enhancements will provide significant long-term benefits to water quality and the environment. This will be accomplished by the facility’s ability to recover resources traditionally classified as waste, improve the facility’s efficiency, and position the City to reduce its dependency on reservoir and groundwater supplies.

While part of the SLO Water Plus project is to make the facility more resilient to natural disasters, the recent rains put the WRRF’s current plans for operating during a severe storm event while under significant operational constraints related to the construction of the new treatment plant, to the test. Physical elements of the risk mitigation strategy included provisions for emergency power, emergency pumping, increased chemical performance, system enhancements, as well as numerous operational control procedures and training.

Concentrated and meticulous planning efforts to reduce operational risk began nearly a year ago and included close collaboration and coordination with various City departments including Utilities, Public Works, Finance, and City Administration/IT departments. These teams worked closely together to collaborate on several diverse ideas and implement best practices for readying the facility to face worst-case scenarios.


“We purposely tried to ‘poke ‘holes’ in the plans along the way so we could identify areas of weakness and make appropriate changes” said Chris Lehman, WRRF Supervisor. “We even worked with our design engineers to put together a model that tested our scenarios in a simulation that was calibrated for an event worse than the storm that we saw last week. Had we not taken planning efforts so seriously, we could have faced some serious issues last week at the facility.”

Despite being one of the biggest storms in recent years, these planning efforts, construction, and upgrades to the facility continued without issue. In addition, the facility maintained the highest possible effluent quality, did not experience any spills despite an increase in storm flows, and the community experienced no disruption to its water and wastewater treatment service. While our community will face additional storms in the future, it is expected that the WRRF will handle those with similar results. 

For more information about the SLO Water Plus project, please visit Community members can also stay up to date on the project’s progress and milestones by signing up to receive project alerts.

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