SR-505-001
EPWM:CP:NS:f/EPWM/ADMIN/Staffrpt/1-25-00/SUSMPS.doc
Council Meeting: January 25, 2000 Santa Monica, California
TO: Mayor and City Council
FROM: City Staff
SUBJECT: Recommendation to Adopt a Resolution to Support the Efforts of the Los
Angeles Regional Water Quality Control Board to Establish a Numerical
Standard for Stormwater Runoff Reductions in the Standard Urban
Stormwater Mitigation Plan.
Introduction
This report recommends that the City Council adopt a resolution in support of the Los
Angeles Regional Water Quality Control Board?s effort to establish a numerical standard
for reducing stormwater runoff from a parcel during each storm event.
Background
Approximately 50 percent of rainfall in the greater Los Angeles area becomes urban runoff,
carrying a mixture of heavy metals, organic chemicals, pathogens, nutrients and sediments
from parking lots, streets, sidewalks, rooftops and yards into the Santa Monica Bay. Urban
runoff, according to the U.S. Environmental Protection Agency, is the single greatest
source of water pollution in the ocean, contributing 50-60 percent of the pollutant load.
Visitation rates to Santa Monica beaches have dropped dramatically during the past 15
years in large part due to more frequent and larger incidents of beach and ocean
contamination. Recent studies have concluded that people who swim near flowing storm
drains are more susceptible to contracting certain illnesses.
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In 1993, Santa Monica adopted one of the nation?s first urban runoff pollution control
ordinances to reduce ocean pollution from both new construction and existing parcels.
The Santa Monica ordinance requires a minimum 20% reduction in urban runoff from all
newly developed parcels in addition to specific runoff reduction requirements for surface
parking lots and also specifies guidelines for existing properties and new construction
sites.
The Executive Officer of the Los Angeles Regional Water Quality Control Board has
recommended a numerical standard for onsite rainfall retention to capture a larger
percentage of runoff events, that is, runoff volume and pollutant loads. The current
recommendation to the Board includes a numerical standard of 0.75 inches per 24-hour
period of rainfall ? the first three-quarters inch of a rain falling in 24 hours must be retained
on site for percolation. By requiring a numerical standard for new development, such as
that found in the City?s Urban Runoff Pollution Ordinance, less urban runoff finds its way to
the Bay, thereby reducing the overall amount of ocean pollution.
Discussion
Many of the co-permittees and regional building associations oppose a numerical standard
for stormwater reduction, citing the potential for excessive costs to be imposed on cities
and private construction projects, concern that BMPs are not effective in removing specific
pollutants, and inadequate information on whether certain pollutants are a problem in the
Bay and need to be controlled in the first place. They support, instead, a regulation that
would require retention to the ?maximum extent practicable?.
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Supporters of the proposed requirements include many individual citizens and major
environmental groups including Heal the Bay, NRDC, BayKeeper and TreePeople. The
environmental groups called for a 100% retention standard originally, but support the
highest possible standard. Many of the interested environmental groups fear that without a
specific numerical standard municipalities will not aggressively require urban runoff
retention since interpretation of maximum extent practicable will be inevitably ambiguous.
The City is the only co-permittee city where staff has publicly expressed support for the
Board?s efforts to approve a numerical standard. The City of Calabasas has a municipal
ordinance similar to Santa Monica?s and has expressed at various meetings its support of
strategies to put more storm runoff back into the ground, but has not publicly commented
on the proposed requirements. The City of Los Angeles opposes a numerical standard.
Los Angeles County has already adopted the same numerical standard for unincorporated
Los Angeles County areas. The current proposal before the Regional Board pertains to
incorporated cities within Los Angeles County.
In their proposal for a numerical standard, Board staff has provided examples of successful
BMP implementation in projects throughout the United States, including the San Francisco
Bay area. Board staff has received authoritative presentations on engineering and
hydrology standards and principles from the Water Environment Federation and the
American Society of Civil Engineers to calculate the optimal rainfall retention amount, and
has drawn from professional publications on proper BMP design and successful practices,
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including a national BMP database.
The guiding premise of Santa Monica?s ordinance, and the proposed Regional Board
requirements, is to focus on the reduction of runoff quantity, which will in turn result in
concomitant pollutant reductions in the storm drain system. In terms of BMP effectiveness,
much empirical data is available to aid in the design and maintenance of systems that
maximize storm harvesting and infiltration. Reducing stormwater pollution through the
intelligent planning and design of new construction, which is the objective of the City?s
ordinance, is the most cost-effective approach to reducing runoff and associated
pollutants. Incorporating BMP systems into future development prevents the existing
problem from getting worse by reducing future runoff and preventing increases in future
costs to remediate the problem.
Budget/Financial Impact
No specific financial impact to the City is anticipated as a result of the City Council?s
support of a numerical standard for the SUSMPs.
Recommendation
Staff recommends that the City Council adopt the attached Resolution in support of the Los
Angeles Regional Water Quality Control Board?s effort to establish a numerical standard
for stormwater runoff reductions from a parcel during a storm event.
Attachment: Resolution of the City Council of the City of Santa Monica in support
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of the LA Regional Water Quality Board efforts to establish a
numerical standard
Prepared by: Craig Perkins, Director of Environmental & Public Works
Management
Neal Shapiro, Urban Runoff Management Programs Coordinator
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