Home Public Works Projects and Programs Alamitos Bay Water Quality Enhancement

Alamitos Bay Water Quality Enhancement

Aerial view of Alamitos Bay

Project updates will be published on an ongoing basis.

Project Updates

September 2025

The Planning Bureau team in the Community Development Department is leading the California Environmental Quality Act (CEQA) process to evaluate environmental impacts for this project in accordance with state regulation and City procedures. The Alamitos Bay Water Quality Enhancement Project - Notice of Availability of a Draft Environmental Impact Report can be accessed online at longbeach.gov/lbcd/planning/environmental/reports. The Notice of Availability (NOA) has specific instructions on how comments on the Draft Environmental Impact Report (DEIR) can be submitted and additional details including information about the public comment period.


Project Information

The Alamitos Bay Water Quality Enhancement (ABWQE) Project protects water quality in Alamitos Bay through monitoring of existing water quality and evaluating alternatives to maintain and improve water quality. The bay is a coastal resource for aquatic recreation, marine habitats and is subject to high levels of human contact year-round through recreation, hosting local and international aquatic events, and supporting future aquatic events for the 2028 Olympic Games. Water quality is influenced by many natural and anthropogenic factors. Development, flood control, and energy generation activities have historically altered the bay. More recently, watershed and waterbody regulations along with projects such as low flow diversions and habitat restorations have corresponded with improvements in water quality. Once-Through-Cooling (OTC) Pumps have been a part of energy generation activities at AES Alamitos for nearly 60 years, their use has decreased since 2018 and are scheduled to be phased out at the end of 2026 under current State regulations. Numerical modeling results indicate that OTC influences the residence time in the bay beyond natural tidal processes. Water quality monitoring is ongoing and an environmental impact report is being prepared to further analyze alternatives.

Operation and regulation of power plants are not within the scope of this project. Private entities and external government agencies oversee the operation and regulation of these facilities.

The California State Water Resources Control Board (State Water Board) is the regulatory agency overseeing the statewide Water Quality Control Policy on the use of water quality control on the use of coastal and estuarine waters for power plant cooling (OTC Policy). Information regarding policy amendment to extend the compliance date of Alamitos Units 3, 4, 5 and other units in the state for three years from December 31, 2023 to December 31, 2026 is available at http://bit.ly/cwa316.

Project Funding

Preliminary engineering for this project is funded by Tidelands and Measure A along with contribution from AES Alamitos.

Project Contact

stormwater@longbeach.gov

More Information

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