For the City of Malibu
Malibu, California

This groundwater quality investigation in the Lower Malibu Creek watershed, a residential and commercial area adjacent to Malibu Lagoon and Surf Rider Beach, had four major components: community and stakeholder outreach, information management, water quality monitoring, and risk assessment. Bruce Douglas of Questa was co-director for this multi-year, $667,000 project, funded by the Coastal Conservancy.  Stakeholder outreach involved state agencies, environmental groups, a neighborhood association, local water districts, and property owners. A Web-based groundwater quality database was developed for long-term subsurface information management. Fourteen newly installed groundwater monitoring wells and six existing wells were sampled monthly for one year. These results, along with hundreds of geotechnical boring logs and previous hydrogeological investigations, were incorporated into a finite-difference computer model to simulate groundwater flow and solute transport. This comprehensive dataset and analytical tool enabled the team to identify bacteria and nitrogen distribution in groundwater, make an informed assessment of the risk of septic system impacts on groundwater quality, and facilitate outcome-driven, fact-based water quality decision-making at the local level.