Un'ted States
Environmental Protection
Agency
Green Infrastructure Program
Community Partner Profiles
2011 Partners
REGION 9: Los Angeles, California
Community Background
The City of Los Angeles is the second largest city in the nation, with
over 3,500,000 people living in an area of about 500 square miles.
The city has 6,500 miles of streets, 10,000 miles of sidewalks, 900
miles of alleys, and over 34,000 catch basins.
The growth of the city and the surrounding metropolitan area has
transformed the area's water cycle and water systems. Eighty
percent of the city's water demand is met by costly imports from distant watersheds. At the same
time, extensive impervious cover and massive stormwater conveyance systems divert half of the rain
that falls in the region to the sea. From the city's earliest days, urbanization exacerbated flooding of
the Los Angeles River and its tributaries. After a series of devastating floods in the first decades of the
20th century, the Los Angeles River and many of its tributaries were channelized. Channelization of the
Los Angeles River was completed in 1960 and formed a 51-mile engineered waterway.
EPA Contact
John Kemmerer
US EPA Southern California
Field Office
600 Wilshire Boulevard
Los Angeles, CA 90017
Drivers for Green Infrastructure
The city of Los Angeles recognizes green infrastructure as a way to address several of its most pressing
environmental and social concerns. Stormwater pollution, water scarcity, and flood events are
important environmental problems that are exacerbated by conventional stormwater infrastructure.
At the same time, the city is interested in increasing recreational opportunities and access to open
space for its residents. Green infrastructure offers an opportunity to advance all these goals at once.
Green Strategies and Programs
Los Angeles recently became a national leader in promoting low impact development. On September
28, 2011, the Los Angeles City Council unanimously passed the Los Angeles Low Impact Development
Ordinance. The ordinance requires that all development projects greater than 500 square feet be
designed to capture, reuse, or infiltrate the runoff generated by the first % inch of rainfall.
EPA 832N12009
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Green Infrastructure Community Partner Profiles
2011 Partners
Los Angeles's Green Alleys Initiative demonstrates how reducing imperviousness and returning
rainwater to natural pathways can advance multiple environmental and community objectives at once.
Los Angeles has approximately 900 linear miles of alleys, most of which are entirely paved and
exacerbate flooding and water quality problems. A 2008 study by the DSC Center for Sustainable Cities
also observed that alleys are concentrated in park-poor communities, where residents have few
opportunities for recreation or outdoor physical activity. Given this strong connection between alleys
and environmental and community health, the City of Los Angeles has initiated a program to introduce
green infrastructure into urban alleys. By adding permeable pavement, bioswales, and drought-
tolerant vegetation to urban alleys, the City can improve water quality, reduce flooding, and reduce
water demand while creating recreational opportunities, increasing neighborhood connectivity, and
even reducing crime (many residents perceive alleys as unsafe. Improving lighting and making alleys
attractive would therefore help address safety concerns and encourage their use.) In September of
2009 Los Angeles completed the first step in implementing the program, publishing "Green Streets and
Green Alleys Design Guidelines and Standards" to assist developers, designers, and engineers in
designing and permitting green alleys.
Los Angeles has also recognized green infrastructure as a way to integrate the goals of reusing existing
urban land, providing water quality and flood management, and providing more public spaces.
Together with the Department of Recreation and Parks, the City Brownfields Team works to identify
brownfield sites, remediate and restore contaminated land, and create natural spaces. These projects
have the potential not only to provide open space and recreational opportunities, but to provide
important links to environment amenities (such as the Los Angeles River) and transportation corridors
(such as bus and light rail stops) as well.
EPA 832N12009
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