Cleaning Urban Stormwater On Its Way To The Ocean: Ecosystem Services From Natural Treatment Systems

Focus Areas > Current Projects > Cleaning Urban Stormwater
Lisa Levin, Scripps Institution of Oceanography, UCSD

Project Overview:

Sustaining adequate water resources is a priority given the ongoing water crisis in Southern California. Vast quantities of water are wasted in urban areas via runoff from storms and daily local usage that flows directly into the ocean.  The journey through impervious urban surfaces such as streets and parking lots accumulates nutrients, metals, fire retardants, pharmaceuticals, and organic contaminants, such as hydrocarbons, into the water. Contamination from runoff is a well-documented problem for both marine life and humans.

One underutilized tool to retain potable water and remove contaminants from runoff are biofilters. Biofilters are constructed to use natural processes, e.g. plant uptake, and living materials, e.g. microorganisms in the soil, to treat urban runoff before it reaches the ocean.  Small biofilter systems have been built in Los Angeles, Orange and San Diego Counties by individual developers, universities, municipalities, transportation authorities and water districts, but there is no comprehensive listing of their location, design, and size. This project will study both the ecology of biofilters and how to optimize the design and locations of biofilters to maximize their benefits.

This project will:

  • Map the locations of existing biofilters in Los Angeles and create an inventory of their size and configuration, design, age, and proximity to drainage pipes, streams and other outlets to the ocean.  This inventory will be cross referenced with the city’s drainage patterns and used to help determine each biofilter’s ability to intercept and treat stormwater flow. 
  • Compile and/or generate information about the ecological attributes of urban biofilters, such as vegetation, soil invertebrates, and sediment that determine their impacts on the environment.
  • Describe and quantify the ecosystem services, e.g. benefits such as water detoxification, from these biofilters in order to help managers assign economic values to them for use in cost-benefit analysis during planning.

Biofilters require low-energy input yet provide multiple benefits including flood and erosion control, biodiversity conservation, and detoxification that can improve the water quality of our coastal ocean. Lisa Levin, the principal investigator of the Sea Grant project, is Director of the Center for Marine Biodiversity and Conservation at Scripps Institution of Oceanography in La Jolla and Distinguished Professor at Scripps. 

Read the summary project proposal.

2017 Research Update:

Key outcomes: 

1) This studycompiled the first database and map of Los Angeles biofilters with information about drainage mechanisms and soil microorganisms. View interactive map of Los Angeles area biofilters:

2) The project looks at biofilters from an ecosystem services perspective, providing the groundwork for monetary valuation of biofilter ecosystem services.

2016 Research Update:

This project generated a lengthy list and interactive map of Los Angeles region biofilters, with information about drainage mechanisms (bioretention vs. biofiltration) and distances that can be used as the basis of applied research by regulators, industry, or academia. The project has provided a first look at biofilters from an ecosystem services perspective and expects to use this information to recommend designs that maximize functions valuable to humans and nature.

This project provides the groundwork for monetary valuation of biofilter ecosystem services, information that could be very persuasive for the adoption and implementation of low impact development plans for jurisdictions that have not yet done so. The project’s faunal studies will contribute to a database used to study the importance of soil invertebrates in biofilter function.

Researchers expect to use this information to recommend designs that maximize the functions of biofilters to capture, treat, and harvest urban stormwater runoff in southern California. 


For more information about the project, contact Phyllis Grifman, Associate Director

Return to list of current projects.

  • USC Sea Grant
  • 3454 Trousdale Pkwy, CAS 200
  • Los Angeles, CA 90089-0373
  • (213) 740 - 1961