On March 2, 2001 the San Diego Regional Water Quality Control Board ("Regional Board") issued a directive, by authority of California Water Code Section 13225, to the County of Orange, the Orange County Flood Control District, and the cities of Laguna Beach, Laguna Hills, Laguna Niguel, Laguna Woods, Lake Forest, Mission Viejo, and Aliso Viejo (Incorporated on July 1, 2001) to investigate urban runoff in the Aliso Creek watershed. The directive found that the "Permittees" may be discharging waste with high indicator bacteria concentrations from municipal stormdrain outfalls into Aliso Creek and its tributaries.
The directive required the Permittees to:
Conduct weekly monitoring at all major outfalls to Aliso Creek
Evaluate the effectiveness of structural and non-structural Best Management Practices (BMPs) currently being implemented in the watershed and identify future measures that would eliminate levels of high bacteria from outfalls.
From 2001-2005 water samples from over 100 monitoring sites along Aliso Creek and its tributaries were tested weekly for indicator bacteria. Many new BMPs were implemented to reduce bacteria levels in the watershed, including wetland restoration projects, a sand and clay filter/ultraviolet treatment system, increased street sweeping, illicit connection inspections, source investigations, and public education and outreach efforts. For a detailed description of implemented BMPs and data resulting from the directive, please see Aliso Creek Watershed 13225 Directive Progress Reports.
Revised Monitoring Program
On October 12, 2005, the Regional Board approved a new monitoring program due to a request from the Permittees, concluding that the proposed changes would constitute an effective interim program until adoption of the Beaches and Creeks Indicator Bacteria TMDLs.
The Revised Monitoring Program was based on the 13225 Directive monitoring data and improved knowledge about overall patterns of bacteria in the watershed and localized responses to specific BMPs. Current monitoring efforts focus on status and trends sites near the bottom of the watershed and BMP evaluation sites at high-priority drains throughout the watershed. Monitoring frequency increased relative to monitoring conducted in 2001-2005, but occurs only in summer when bacteria concentrations are highest.