State Water Board enhances monitoring strategies for harmful algal blooms in California Delta

The recent Water Quality Coordinating Committee (WQCC) meeting held by the State Water Resources Control Board on May 7, 2025, highlighted critical discussions surrounding the management of harmful algal blooms (HABs) in California's water bodies, particularly in the Delta region. As the frequency and severity of these blooms rise, officials are prioritizing enhanced monitoring and collaborative strategies to safeguard public health and environmental integrity.

One of the key topics addressed was the need for improved monitoring of cyanobacterial harmful algal blooms (CHABs), which have become increasingly prevalent in the Delta, especially during drought conditions. Laura Thwarte Club, an environmental program manager, emphasized the importance of establishing a coordinated monitoring program to better understand the status and trends of CHABs. Currently, monitoring efforts are fragmented among various agencies, leading to gaps in data and response capabilities. The proposed new monitoring provisions in the 2024 draft Bay Delta Plan aim to address these limitations by introducing specific monitoring for cyanobacterial species and toxins at identified hotspots.

The meeting also underscored the collaborative efforts among state agencies, local health departments, and community organizations to tackle the challenges posed by HABs. Meredith Howard from the Central Valley Water Board discussed the development of decision support tools and partnerships to enhance data collection and management strategies. These initiatives are crucial for identifying hotspots and implementing effective mitigation measures.

In addition to monitoring, the committee explored the implications of nutrient loading from wastewater discharges, which can exacerbate algal blooms. Nick Martirano, Assistant Deputy Director, highlighted ongoing projects aimed at establishing water quality objectives for cyanotoxins and controlling nutrient inputs to reduce the occurrence of harmful blooms.

The discussions also touched on the role of public health communication in managing risks associated with HABs. The need for clear thresholds and guidelines for local health officers was identified as a priority to ensure timely and effective public notifications regarding water safety.

As California continues to grapple with the impacts of climate change and increasing nutrient pollution, the outcomes of this meeting signal a concerted effort to enhance water quality management and protect both public health and aquatic ecosystems. The next steps involve refining monitoring strategies, engaging stakeholders, and developing actionable plans to address the growing threat of harmful algal blooms across the state.