pp/y Clean Water State Revolving Fund
Green Project Reserve
Clean Water
Case Study: El Cerrito Green Street Project
Integrating Green Infrastructure with Community Needs
The San Francisco Bay-Delta Estuary is the largest estuary on the West Coast. It provides water for
irrigation of 7,000 square miles of farmland, drinking water to 25 million people, and habitat for over
numerous species, including salmon, waterfowl, and shorebirds. (For more information about the estuary
see: http://www.epa.gov/sfbay-delta/basicinfo.html) However, this valuable resource is threatened by
pollutants in stormwater runoff. The El Cerrito Redevelopment Agency, in combination with the San
Francisco Estuary Partnership, obtained a $392,000 loan in the form of 100 percent principal forgiveness
through the American Recovery and Reinvestment Act (ARRA) for the construction of a series of rain
gardens and bioswales along San Pablo Avenue in El Cerrito, California. The loan was administered
through the California Clean Water State Revolving Fund as a part of the Green Project Reserve. This
"green street" project has lessened the amount of polluted runoff entering the estuary system by
implementing green infrastructure stormwater solutions that allow for natural infiltration and
evapotranspiration of rainwater.
Benefits of Green Infrastructure
Green infrastructure allows for runoff to more closely
mimic natural hydrology. While traditional gray
stormwater infrastructure collects runoff in storm
sewers or combined sewer systems and can allow
pollutants to enter waterways, green infrastructure
captures the rainwater where it falls and allows it to
naturally infiltrate into the ground. There are a number
of benefits associated with these more natural
processes. For example, as water percolates through
soil, pollutants like heavy metals, pesticides, bacteria,
nutrients and sediments are naturally reduced. This
lessens the nonpoint source pollutant load to
surrounding surface waters and benefits the
environment by improving water quality, reducing
water temperatures, and creating habitat in which both
flora and fauna may flourish. Additionally, the risk of
overflow events, which lead to untreated water being
discharged to the watershed, is reduced. The increase in
plants and vegetation also creates more wildlife habitat
and enhances the appearance and livability of the
community.
Rain Gardens along San Pablo Avenue
There is a broad range of options for sustainable
management of stormwater runoff, including rain gardens, bioswales, green roofs, green walls, and
permeable pavement. Each of these options serves as a way to stop or slow the flow of contaminated
stormwater runoff, easing the impact on the stormwater system and the watershed by containing
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rainwater on-site. According to San Francisco's Stormwater Management Ordinance (Available at:
http://www.sfbos.org/ftp/uploadedfiles/bdsupvrs/ordinanceslO/o0083-10.pdf), developers disturbing more
than 5,000 square feet are responsible for managing stormwater on-site. While this ordinance is
undoubtedly beneficial for the Estuary, the question of stormwater management in public rights-of-way
is more complicated. The El Cerrito project faced this green infrastructure challenge head-on.
Green Streets in El Cerrito
The decision to undertake the "greening" of two stretches of San Pablo Avenue (see picture on right) in
El Cerrito can be largely attributed to the environmental benefits that green infrastructure solutions can
offer. Neighborhood stakeholders shared a common vision to turn the San Pablo Avenue corridor into a
more walkable environment and a welcoming feature of the community. They believed that using rain
gardens would not only address the community's stormwater pollution issues effectively, but that the
beautification of San Pablo Avenue would enhance the quality of life and economic vitality of the
community. In this sense, the goals of the local businesses and those of the local government
overlapped.
Ultimately, the decision was made to create a demonstration project that would not only benefit the
environment and the community, but would also serve as a model for future green infrastructure
projects. Two block-long stretches of San Pablo Avenue were updated with curb cuts leading to
vegetated treatment basins. These treat runoff from 1.23 acres of impervious surface and serve as a
highly visible example of green infrastructure in the community. Constant water quality monitoring will
track the success and efficacy of the rain gardens in treating contaminated stormwater runoff. (Further
information available at: http://www.sfestuary.org/projects/detail.php?projectlD=41)
The greatest challenge in the planning phase of the El Cerrito project was not the engineering aspect -
the technological requirements of bioswale construction are well established. Instead, it was the
logistical aspects: finding enough land in public rights-of-way that were available for green
infrastructure, avoiding underground utilities in the area, and coordinating the presence of rain gardens
with the need for ample sidewalk space, light posts, bus stops, and other public amenities. However,
careful planning, cooperative effort from all parties involved, and flexibility in the face of the
unexpected - such as the discovery of an underground waterline during construction - ensured the
success of this project. Post-construction maintenance of the rain gardens and bioswales had to be
considered as well. Overall, the ongoing maintenance required will be primarily that of a landscape
feature, including occasional watering and trimming as well as trash removal. To minimize these needs,
native plants were chosen which require very little watering and attention. The plants are also relatively
stable in terms of size and require minimal trimming to keep roads and sidewalks clear. (Video available
at: http://www.youtube.com/watch?v=aErRvs35Ttw)
Impact Beyond El Cerrito
Although the planning phase of the El Cerrito project was challenging, to some extent these difficulties
were embraced as a way to add to its demonstration value. One of the primary goals of this project was
to demonstrate the value and feasibility of green infrastructure, which can now include examples of
how to overcome challenges for future green street planners. The demonstration aspect of the El Cerrito
project is already beginning to reap rewards. San Pablo Avenue has received a lot of attention for its
benefits to the watershed, including acknowledgment from the California Department of
Transportation, who may consider using this project as a guide in the greening of future roadways.
Much of this impact has been attributed to the use of partnerships that brought attention to the project
from outside El Cerrito.
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Interpretative signage and post-project water quality monitoring will also enhance the demonstration
impact of the project. To many people, rain gardens are a beautiful addition to the street, but their
environmental benefits may be overlooked or not well understood. Interpretative signage will help to
spread the word regarding the benefits of green infrastructure. Similarly, the results of water quality
monitoring will be included in a report to the State Water Resources Control Board and will be used in
materials for the community. Monitoring will include measurements of pollutants such as PCBs,
pyrethroids, suspended sediment, mercury, copper, and organic carbon both at the inlet and the outlet.
This will provide a comprehensive view of the way that the green street project impacts stormwater
runoff in El Cerrito and, ultimately, the San Francisco Bay.
For more information please contact the California Clean Water State Revolving Fund Program
CleanWaterSRF@waterboards.ca.gov
916-327-9978
http://www.waterboards.ca.gov/waterjssues/programs/grantsjoans/srf/
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