Marie Canyon Water Quality Improvement Project

About the Program

Category: County Resiliency (Best in Category)

Year: 2010

The Marie Canyon watershed in Malibu, California was an ideal location to improve water quality. The beach at the canyon often had a higher bacteria count than any other location in Santa Monica Bay. Heal the Bay ranked this beach as one of the three worst for water quality in the State for three consecutive years. To improve water quality near Marie Canyon, the Los Angeles County Flood Control District applied for a State grant from the California State Water Resources Control Board under Proposition 13, Non-point Source Pollution Control Grant Program. The demonstration project would be able to reduce the bacteria levels often present in dry-weather urban runoff to meet the established standards for human contact recreation. After forming a Technical Advisory Committee and engaging local residents in the development process, the County constructed a series of six multimedia filers and two ultraviolet disinfection units that remove bacteria and viruses that may be present in dry weather urban runoff carried through the storm drain. The system can treat as much as 100 gallons per minute. This is roughly triple the average amount of dry weather runoff flowing from Marie Canyon. Now pollutants and bacteria are removed before they reach the public beach at the canyon’s ocean outlet.