Santa Ana Water Board strengthens nutrient contaminant levels for Lake Elsinore, Canyon Lake

RIVERSIDE – In a move designed to improve water quality in Lake Elsinore and Canyon Lake, the Santa Ana Regional Water Quality Control Board today adopted stricter limits on nutrients that can lead to harmful algal bloom eruptions, threaten aquatic habitat and restrict recreational opportunities.

The lakes in western Riverside County have long faced challenges related to excessive amounts of nutrients – primarily nitrogen and phosphorous – that fuel toxic algal growth and deplete oxygen needed for marine life, resulting in fish kills and posted advisories urging the public in affected areas not to participate in water-related outdoor activities.

The Santa Ana Water Board initially adopted the Total Maximum Daily Loads (TMDLs) – which define how much of a specific pollutant a waterbody can tolerate and meet water quality standards - in 2004. The revisions establish interim and final numeric targets for chlorophyll-a, ammonia and dissolved oxygen to reduce nutrient loads from both external sources (watershed runoff) and internal sources (lake bottom sediments).

“This significant step reflects our commitment to improve water quality and protect the beneficial uses of these vital waterbodies in the San Jacinto River watershed,” said regional board Chair Kristine Murray. “Through a collaboration with our partners, we have made significant strides in both Lake Elsinore, which is a natural waterbody, and Canyon Lake, a man-made reservoir.”

The TMDL is the result of extensive scientific research and a new approach that utilizes advanced water quality models to determine achievable targets. The joint effort involved the board, the Lake Elsinore and San Jacinto Watersheds Authority, and the Lake Elsinore and Canyon Lake TMDL Task Force, which includes stakeholders from municipal, state, federal, tribal agencies and agricultural interests.

“These lakes are central to the identity and quality of life in our region,” said Bob Magee, chair of the watershed authority. This revised TMDL is more than a regulatory update. It’s a foundation for restoration, resilience and renewed recreational opportunity. We appreciate the leadership of the Santa Ana Water Board and the countless agencies and stakeholders who help bring this effort to fruition.”

To implement the changes that officially amend the region’s Basin Plan, a comprehensive set of tasks and schedules was established that includes continued and expanded nutrient control measures, in-lake projects such as the Lake Elsinore Aeration and Mixing System, Canyon Lake alum applications and monitoring programs to track progress.

The plan will be administered in three phases: Phase 1 (2005-2020) focused on initial nutrient reduction efforts; Phase II includes milestones and interim numeric targets to be achieved within 20 years; and Phase III (20-30 years) sets final numeric targets and allocations to be achieved within 30 years.

The Santa Ana region, which extends from the San Bernardino and San Gabriel mountains to the north and east, to Newport Bay along the coast, is one of the fastest growing areas of the state. Though geographically the smallest of the Water Boards’ nine regions, the Santa Ana regional staff strives to protect, enhance and restore water quality for almost 5 million Californians.