A state requirement that power plants stop using ocean water to cool their systems could have the unintended consequence of worsening overall water quality in Alamitos Bay, according to a city report.

But fixing it would likely cost the city millions of dollars.

Power plants will soon be banned from using ocean water, a state mandate intended to protect fish and other critters from being sucked into cooling pipes and pumps. The deadline for the Alamitos Energy Center to comply with the mandate is Dec. 31, 2023.

On an average day in 2019, the Alamitos Energy Center pumped approximately 326 million gallons of seawater from the Alamitos Bay into the San Gabriel River, mixing ocean and bay water, which improves circulation and water quality, according to the report.

More stagnant water means lower quality across the Alamitos Bay, the report states.

The water at Mother’s Beach, for example, is currently going through a complete exchange every 3.4 days. Once pumping stops, that number would increase to 9.5 days.

A lack of circulation could also lead to prolonged periods of elevated bacteria concentrations in certain areas and increased temperatures that could lead to algae blooms, according to Moffat & Nichol, the engineering firm tasked with studying the impacts of phasing out the current pump system and identifying an alternative.

Further, “without the pumps, trash will flow into the Bay and be moved around with the tidal currents,” the report noted.

After months of review, Moffat & Nichol is suggesting the installation of fish-friendly pumps, which would allow the ocean’s fauna to swim through the pipes unharmed while maintaining the current water circulation, according to the report.

But these pumps would be of no use to the power plant, making it the city’s responsibility to pay for planning, installation and maintenance.

Overall, capital costs for the project are estimated at $35 million and annual operating costs are estimated at $2 million. So far, the city has used Tideland funds to pay for projects of this type, which come mostly from oil drilling revenue. But those funds have been significantly impacted by effects of the coronavirus due to the plummeting cost of oil.

“There’s still some work to be done in creating a financial plan to support it,” Deputy City Manager Kevin Jackson said. “But we do anticipate that the city would be principally responsible, financially.”

To soften the blow in light of a city budget that’s already been stretched by the economic impacts of the coronavirus pandemic, Jackson said any financial plan will likely include a strong emphasis on grants. A memorandum of understanding with AES California, the plant’s operator, will likely be finalized within the coming months and would solidify the exact terms of the agreement, he added.

Waterways in Long Beach, particularly Colorado Lagoon, suffered from some of the worst water quality in the region and state less than a decade ago. Alamitos Bay and Mother’s Beach earned a “D” and “F,” respectively on Heal the Bay’s 2011 survey of water quality in the state.

The city worked to secure grants and other funding to clear contaminated sediment and improve circulation in the lagoon and bays, and most sections of Alamitos Bay, Mother’s Beach and Colorado Lagoon—all popular swimming locations—received “A” and “B” grades in the most recent report in June.

“This project is critically important because the Alamitos Bay is an important resource for the community,” Jackson said.