State Water Board approves Santa Ana Region's copper TMDLs for Upper and Lower Newport Bay; phased boat‑focused reductions and adaptive review included

The State Water Resources Control Board on Aug. 5 approved copper TMDLs for Upper and Lower Newport Bay developed by the Santa Ana Regional Water Quality Control Board. The action responds to dissolved copper exceedances of the federal California Toxics Rule (CTR) criteria and sediment concentrations above NOAA guidance in some locations; staff identified vessel antifouling paints as the largest remaining source and proposed phased reductions that focus on recreational and small commercial boats.

The TMDLs set numeric targets based on the CTR (acute and chronic criteria) and a sediment guidance benchmark (NOAA effect‑range low). Staff estimated annual inputs at roughly 18,000 pounds of copper per year from vessel paints and proposed phased waste‑load reductions for the vessel source: 20% in four years, 40% in eight years and 60% in 12 years, with earlier attainment of CTR or site‑specific objectives treated as meeting the TMDL. The implementation strategy emphasizes a suite of measures: diver and boater education, diver certification programs, in‑water hull‑cleaning best practices, incentives for non‑biocidal paints and alternatives such as floating dry docks or dry storage, and local encouragement of lower‑leach‑rate antifouling paints.

Public commenters raised concerns that non‑biocidal alternatives may introduce PFAS, that other harbors (Shelter Island, Marina del Rey) have not achieved CTR compliance through outreach and BMPs alone, and that local jurisdictional authority for paint sales rests with state pesticide regulators. Regional staff and the board acknowledged these issues, noted that the TMDL does not require non‑biocidal paints, and committed to adaptive management and collaborative implementation with cities, counties, ports, marina operators and stakeholders. The board adopted the resolution by roll call vote and asked the Santa Ana board staff to continue stakeholder coordination, periodic technical reviews and reanalysis at the 4‑, 8‑ and 12‑year check points.