RPVCCA_CC_SR_2015_04_07_01_Low_Impact_Development_Ord_&_Green_Streets_PolicyMEMORANDUM
TO: HONORABLE MAYOR &CITY COUNCIL MEMBERS
FROM: MICHAEL THRONE, PUBLIC WORKS DIRECTOR (,{�(
DATE: APRIL 7, 2015
SUBJECT: FIRST READING OF LOW IMPACT DEVELOPMENT
ORDINANCE AND ADOPTION OF GREEN STREETS
POLICY
REVIEWED: DOUG WILLMORE, CITY MANAGER
Project Manager: Andy Winje, Senior Engineer
RECOMMENDATION
1. Introduce Ordinance No. ,
AN ORDINANCE OF THE CITY OF RANCHO PALOS VERDES, CALIFORNIA,
AMENDING RANCHO PALOS VERDES MUNICIPAL CODE CHAPTER 13.10, TO
EXPAND THE APPLICABILITY OF THE EXISTING STORM WATER AND URBAN
RUNOFF POLLUTION CONTROL BY IMPOSING RAINWATER LOW IMPACT
DEVELOPMENT (LID) STRATEGIES ON PROJECTS THAT REQUIRE BUILDING,
GRADING AND ENCROACHMENT PERMITS.
2. Adopt Resolution No. 2015-
A RESOLUTION OF THE CITY COUNCIL OF THE CITY OF RANCHO PALOS
VERDES, CALIFORNIA, APPROVING A GREEN STREETS POLICY
EXECUTIVE SUMMARY
The City's response to the demands of the new MS4 Storm Water Quality Permit (Permit)
includes development of an Enhanced Watershed Management Program (EWMP), which
requires agencies to develop and have in place a Low Impact Development (LID)
ordinance meeting the requirements of this Order's Planning and Land Development
Program. In addition the City is required to adopt a Green Streets policy that specifies
the use of green infrastructure strategies for transportation corridors in order to be in
compliance. The City has yet to adopt either of these and it is now time to do so. The
deadline for these to be in place is June 2015.
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INTRODUCTION
The latest MS4 Permit (Order No. R4-2012-0175) was adopted by the California Regional
Water Quality Control Board, Los Angeles Region (Regional Board) on November 8,
2012. The new Permit is considerably more complicated than the last one, and requires
the City to create new programs and enhance existing ones. One required enhancement
is the adoption of additional requirements that reduce the water quality impacts of
stormwater and urban runoff for new and redevelopment projects on commercial,
institutional, industrial and residential properties. A second program is the adoption of
green infrastructure strategies on the City's transportation corridors. A period of up to 30
months from the Permit's effective date was allowed to develop the required programs to
implement the various compliance measures in the Permit. The 30 -month period ends in
June of this year.
Low Impact Development consists of building and landscape features designed to retain
or filter stormwater runoff. These treatment systems work to reduce pollutant levels from
their associated drainage area to improve the quality of runoff. The installation of these
treatment systems can be low-cost and generally require low -maintenance, often being
incorporated into the parcels' landscape theme.
Roads also present opportunities for green infrastructure application. Green Streets
infrastructure approaches complement street facility upgrades, street aesthetic
improvements, and urban tree canopy efforts that also make use of the right-of-way and
allow it to achieve multiple goals and benefits. Using the right-of-way for treatment of
stormwater runoff links green with grey infrastructure by making use of the engineered
conveyance of roads and providing connections to other drainage systems when needed.
Green Streets can incorporate a wide variety of design elements including street trees,
permeable pavements, bioretention, and swales. Although the design and appearance
of green streets will vary, the functional goals are the same; provide source control of
stormwater, limit its transport and pollutant conveyance to the collection system, restore
pre -development hydrology to the maximum extent practicable, and provide
environmentally enhanced roads. Successful application of green techniques will
encourage soil and vegetation contact and infiltration and retention of stormwater.
BACKGROUND
The City Council is familiar with the increased requirements of the new MS4 Permit. Staff
has sought City Council approval on several occasions to meet the various milestones to
achieve Permit compliance. At its June 18, 2013 meeting, the City Council authorized
Staff to notify the Regional Board that the City would follow the EWMP approach in
collaboration with other peninsula agencies. A Notice of Intent was filed on June 27, 2013
and subsequently approved by the Regional Board. At the June 17, 2014 meeting, the
City Council directed staff to submit the EWMP Workplan and submit a draft monitoring
program, in accordance with the schedule presented by the Regional Board. The
Workplan was approved and a final EWMP document is currently being prepared for
submission to the Regional Board this June. The Coordinated Integrated Monitoring
Program (CIMP) draft document was also submitted last June and comments were
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received this February. A response to comments is being prepared for resubmission as
a step towards finalization of the CIMP. Implementation of the CIMP will being in 2015.
Implementation of the EMWP will begin upon its approval, most likely in 2016.
DISCUSSION
LID Ordinance
The goals of Low Impact Development include: (1) reducing the amounts of pollutants in
stormwater and urban runoff, (2) providing specifications for low cost treatment systems
that are easy for the property owner to install, and (3) encouraging property owners to
select treatment systems that are easy to maintain and thus minimizing the need for City
enforcement.
Staff has developed a Low Impact Development (LID) ordinance designed to meet these
goals. This ordinance will contribute to improving storm water quality by capturing or
treating stormwater runoff close to its source, that is, while still on the property onto which
it falls. New and redevelopment projects will need to control pollutants, pollutant loads,
and runoff volume to the maximum extent feasible by minimizing impervious surface area
and controlling runoff from impervious surfaces through infiltration, evapotranspiration,
bioretention and/or rainfall harvest.
The ordinance will repeal and replace the current municipal code Section 13.10 STORM
WATER AND URBAN RUNOFF POLLUTION CONTROL. Specifically, the ordinance
updates the list of definitions, which are provided in Permit language, adds a section on
allowable discharges, strengthens language on the good housekeeping requirements of
owners and occupants of existing properties, replaces the current SUSMP development
requirements with the new Low Impact Development requirements that require
submission and City approval of a Storm Water Mitigation Plan, lowers the threshold for
qualifying projects, eliminates the granting of waivers by the City for otherwise qualifying
projects, and sets the conditions for inspections on private property. The ordinance
impacts new development and redevelopment projects subject to City conditioning and
approval as follows:
New Development
1. All development projects equal to 1 acre or greater of disturbed area that add
more than 10,000 square feet of impervious surface area.
2. Industrial parks and commercial malls 10,000 square feet or more of surface
area.
3. Retail gasoline outlets, auto service facilities and restaurants with 5,000 square
feet or more of surface area.
4. Parking lots with 5,000 square feet or more of impervious surface area, or with
25 or more parking spaces.
5. Projects located in or directly adjacent to, or discharging directly to an
Environmentally Sensitive Area.
6. Single family hillside homes. (The requirements for single family hillside homes
with less than 10,000 square feet of surface area are significantly less than
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those for the other projects in this list and emulate the requirements of the
existing SUSMP program).
Redevelopment Projects:
Land disturbing activity that results in the creation or addition or replacement
of 5,000 square feet or more of impervious surface area on an already
developed site for categories identified above.
2. Where Redevelopment results in an alteration to more than fifty percent of
impervious surfaces of a previously existing development, and the existing
development was not subject to post -construction stormwater quality control
requirements, the entire project must be mitigated.
3. Where Redevelopment results in an alteration of less than fifty percent of
impervious surfaces of a previously existing development, and the existing
development was not subject to post -construction stormwater quality control
requirements, only the alteration must be mitigated, and not the entire
development.
4. Redevelopment does not include routine maintenance activities that are
conducted to maintain original line and grade, hydraulic capacity, original
purpose of facility or emergency redevelopment activity required to protect
public health and safety. Impervious surface replacement, such as the
reconstruction of parking lots and roadways which does not disturb additional
area and maintains the original grade and alignment, is considered a routine
maintenance activity. Redevelopment does not include the repaving of existing
roads to maintain original line and grade.
5. Existing single-family dwelling and accessory structures are exempt from the
Redevelopment requirements unless such projects create, add, or replace
10,000 square feet of impervious surface area.
The Storm Water Mitigation Plan prepared by the developer must demonstrate that the
completed project will retain runoff on site from a given design storm. In the event this
cannot be done due to technical infeasibility, a plan for treatment of the design storm
through filtration will be required.
There are certain exemptions from the ordinance for emergency construction activity to
immediately protect health and safety, projects within the right of way, utility work,
resurfacing or restriping parking areas. There is also relief from certain expectations, like
infiltration, due to technical infeasibility. For instance, where infiltration might create a
geotechnical hazard or contaminate groundwater supplies of drinking water, retention
might be exempt.
The City currently has a program with similar requirements for management of post
construction storm water quality from development and redevelopment projects. This
new ordinance, however, significantly decreases the methods, often ineffective, by which
developers can achieve compliance. Whereas in the past, a developer might select a
suite of best management practices (BMPs) to achieve his ends, the ordinance requires
he follow a specific methodology and be subject to inspection and enforcement, including
civil action. Violation of the ordinance shall be punishable under RPV Municipal Code
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Section 1.08.010 - Misdemeanors—Infractions—Nuisances.
The specifics of the requirements and exemptions can be seen in the attached copy of
the ordinance, designated as Attachment A
Green Streets Resolution
The Permit and ordinance also require that certain new road construction projects and
redevelopment of roadways shall be subject to a City Council adopted Green Streets
policy, including the City of Rancho Palos Verdes Green Streets Manual. Staff has
developed a resolution, attached and designated as Attachment B, which memorializes
the adoption of the policy. Similar to LID, the Green Streets policy provides source
controls for stormwater runoff and pollutant loads. However, this policy is for right of way
improvements rather than parcels.
The proposed policy shall require projects which fall into the following categories to follow
the City's Green Streets Manual, which is attached as Exhibit A of the resolution:
1. Street and road construction of 10,000 square feet or more of impervious surface
area.
2. Street and road redevelopment resulting in the creation or addition or replacement
of 5,000 square feet or more of impervious surface area on an already developed
site.
Redevelopment does not include routine maintenance activities that are conducted to
maintain original line and grade, hydraulic capacity, original purpose of facility or
emergency redevelopment activity required to protect public health and safety.
Impervious surface replacement, such as the reconstruction of parking lots and roadways
which does not disturb additional area and maintains the original grade and alignment, is
considered a routine maintenance activity. Redevelopment does not include the repaving
of existing roads to maintain original line and grade.
Like the LID ordinance, the Green Streets Manual provide for exceptions when technical
infeasibilities occur and takes into account the limitations of site conditions. It also allows
for off-site mitigation projects, which would give the City some flexibility when
implementing the policy in tight areas. Some Green Street methods also dovetail nicely
into traffic calming measures, which is already a program being implemented by the City.
CONCLUSION
The Regional Board has required that MS4 Permittees using an EWMP to achieve Permit
compliance must adopt an LID ordinance and a Green Streets policy by June of this year.
Staff from the Community Development Department and the Public Works Department
have collaborated to prepare the LID ordinance and a resolution adopting the Green
Streets policy under the technical guidance of the City's storm water quality consultant,
John L. Hunter and Associates. The LID ordinance and the Green Streets policy will
serve to improve the quality of storm water and urban runoff by capturing and or treating
water close to its source. The City Attorney's office has reviewed and approved the
language of both the ordinance and the resolution. Staff recommends City Council adopt
both the LID ordinance and the Green Streets policy resolution in order to achieve prompt
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Permit compliance.
FINANCIAL IMPACT
There is no direct fiscal impact to the City from adopting the LID ordinance. There will
be an increase in time spent reviewing plans. However, this cost will be offset by
increased fees collected from the developer at the time of plan review.
The impact to the City due to adoption of the Green Streets policy cannot be accurately
estimated at this time. The Green Streets policy could potentially add costs to new City
street projects when they are built. However, since the City's road network is almost
entirely in place and because most currently programmed City projects have to do with
maintaining existing facilities, which are largely exempt, the impacts are fairly small as a
percentage of the programmed capital costs attributable to street and road projects.
Attachments: A: Low Impact Development Ordinance (Page 7)
B: Green Streets Policy Resolution including Exhibit A — Green
Streets Policy Manual (Page 33)
Al
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ATTACHMENT A
ORDINANCE NO.
AN ORDINANCE OF THE CITY COUNCIL OF THE CITY OF
RANCHO PALOS VERDES, CALIFORNIA, AMENDING
RANCHO PALOS VERDES MUNICIPAL CODE CHAPTER
13.10 (STORM WATER AND URBAN RUNOFF
POLLUTION CONTROL), TO INCLUDE LOW IMPACT
DEVELOPMENT REQUIREMENTS AND ADDITIONAL
REVISIONS PURSUANT TO THE NATIONAL POLLUTANT
DISCHARGE ELIMINATION SYSTEM PERMIT
REQUIREMENTS FOR THE MUNICIPAL SEPARATE
STORM SEWER SYSTEM
WHEREAS, the City is authorized by Article XI, Section 5 and Section 7 of
the State Constitution to exercise the police power of the State by adopting regulations to
promote public health, public safety and general prosperity; and
WHEREAS, the federal Clean Water Act establishes Regional Water
Quality Control Boards in order to prohibit the discharge of pollutants in stormwater runoff
to waters of the United States; and
WHEREAS, the City is a permittee under the California Regional Water
Quality Control Board, Los Angeles Region Order No. R4-2012-0175, issued on
November 08, 2012 which establishes Waste Discharge Requirements for Municipal
Separate Storm Sewer Systems (MS4) Discharges within the Coastal Watersheds of Los
Angeles County, Except those Discharges Originating from the City of Long Beach MS4;
and
WHEREAS, Order No. R4-2012-0175 contains requirements for
municipalities to establish an LID Ordinance in order to participate in a Watershed
Management Program and/or Enhanced Watershed Management Program; and
WHEREAS, the Regional Board has adopted Total Maximum Daily Loads
(TMDLs) for pollutants which are numerical limits that must be achieved effectively
through LID implementation; and
WHEREAS, the City has the authority under the California Water Code to
adopt and enforce ordinances imposing conditions, restrictions and limitations with
respect to any activity that might degrade waters of the State; and
WHEREAS, the City is committed to a stormwater management program
that protects water quality and water supply by employing watershed -based approaches
that balance environmental and economic considerations; and
WHEREAS, urbanization has led to increased impervious surface areas
resulting in increased water runoff and less percolation to groundwater aquifers causing
the transport of pollutants to downstream receiving waters; and
WHEREAS, is it the intent of the City to expand the applicability of the
existing LID requirements by providing stormwater and rainwater LID strategies for all
projects for Development and Redevelopment projects where technically feasible, as
defined herein.
Page 1 of 26
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NOW, THEREFORE, THE CITY COUNCIL OF THE CITY OF RANCHO
PALOS VERDES, CALIFORNIA, DOES HEREBY ORDAIN AS
FOLLOWS:
SECTION 1. The City Council hereby finds, in the exercise of its independent
judgment and analysis, that this Ordinance is exempt from the California Environmental
Quality Act ("CEQA") because the Low Impact Development requirements for new
development and redevelopment projects of this Ordinance will not have a significant
effect on the environment, and the adoption of this Ordinance and the timing thereof is
mandated by the action of the Los Angeles Regional Water Quality Control Board
("LARWQCB"). In this case, the City is acting at the direction of the LARWQCB and
federal law to protect, maintain, restore and enhance natural resources and the
environment. To comply with the requirements of the LARWQCB, the City Council finds
that the adoption of this Ordinance is categorically exempt from the requirements of the
California Environmental Quality Act ("CEQA") pursuant to CEQA Guidelines Sections
15307 and 15308. Furthermore, this Ordinance will have no possible significant effect on
the environment, given that the provisions of this Ordinance provides similar regulations
as currently exist and will not in and of themselves cause any change in the environment.
Staff is hereby directed to prepare and post a notice of exemption pursuant to Guidelines
Section 15062.
SECTION 2. Section 13.10.010 of the Rancho Palos Verdes Municipal Code
entitled "Findings" is hereby repealed in its entirety and shall be replaced with the
following:
"13.10.010 — Findings.
A. The Congress of the United States (hereinafter "Congress") has
determined that pollutants contained in storm water and urban runoff are responsible for
the environmental degradation of oceans, lakes, rivers, and other waters of the United
States.
B. Congress, in 1987, amended the Clean Water Act of 1972 to reduce
pollutants discharged into the waters of the United States by extending National
Pollutant Discharge Elimination System (hereinafter "NPDES") requirements to regulate
storm water and urban runoff discharge into municipal storm drain systems.
C. Storm water and urban runoff flows from individual properties onto streets,
then through storm drains to coastal waters along the City of Rancho Palos Verdes.
D. The City of Rancho Palos Verdes is a co -permittee under the Municipal
NPDES Permit issued by the California Regional Water Quality Control Board, Los
Angeles Region, which also serves as a NPDES Permit under the Federal Clean Water
Act and as a co -permittee, the City is required to implement procedures with respect to
the entry of non -storm water discharges into the municipal storm water system.
E. In order to control, in a cost-effective manner, the quantity and quality of
storm water and urban runoff to the maximum extent practicable, the adoption of
reasonable regulations, as set forth herein, is essential.
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SECTION 3. Section 13.10.020 of the Rancho Palos Verdes Municipal Code
entitled "Purpose" is hereby repealed in its entirety and shall be replaced with the
following:
"13.10.020 — Purpose.
A. The purpose of this chapter is to ensure the future health, safety and
general welfare of the citizens of the City and the water quality of the Santa Monica Bay
and surrounding coastal areas by:
1. Reducing pollutants in storm water discharges to the maximum extent
practicable;
2. Regulating illicit connections and illicit discharges and thereby reducing
the level of contamination of storm water and urban runoff into the
municipal storm water system; and
3. Regulating non -storm water discharges to the municipal storm water
system.
B. This chapter also sets forth requirements for the construction and
operation of certain commercial development, new development and redevelopment
and other projects (as further defined herein) which are intended to ensure compliance
with the storm water mitigation measures prescribed in the current version of the
Municipal NPDES Permit approved by the Regional Water Quality Control Board, Los
Angeles Region, and on file in the office of the City clerk.
C. This chapter authorizes the Authorized Enforcement Officer to define and
adopt applicable Best Management Practices and other storm water pollution control
measures and to cite infractions and to impose fines pursuant to this chapter. Except as
otherwise provided herein, the Authorized Enforcement Officer shall administer,
implement and enforce the provisions of this section.
D. The intent of this chapter is to protect and enhance the quality of
watercourses, water bodies, and wetlands within the City in a manner consistent with
the federal Clean Water Act and the NPDES Permit.
E. This chapter is also intended to provide the City with the legal authority
necessary to control discharges to and from those portions of the municipal storm water
system over which it has jurisdiction as required by the municipal NPDES Permit."
SECTION 4. Section 13.10.030 of the Rancho Palos Verdes Municipal Code
entitled "Definitions" is hereby repealed in its entirety and shall be replaced with the
following:
"13.10.030 — Definitions.
Except as specifically provided herein, any term used in this chapter shall be
defined as that term is defined in the current municipal NPDES Permit, or if it is not
specifically defined in the municipal NPDES Permit, then as such term is defined in the
Federal Clean Water Act, as amended, and/or the regulations promulgated hereunder.
If the definition of any term contained in the current municipal NPDES Permit conflicts
with the definition contained in this Chapter, then the definition contained in the
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municipal NPDES Permit shall govern. The following words and phrases shall have the
following meanings when used in this chapter:
A. "Area Susceptible to Runoff" means any surface directly exposed to
precipitation or in the path of runoff caused by precipitation which path leads off the
parcel on which the surface is located.
B. "Authorized Enforcement Officer" means the Director of the
Department of Public Works on his or her designee.
C. "Automotive Service Facility" means a facility that is categorized in any
one of the following Standard Industrial Classification (SIC) and North American
Industry Classification System (NAICS) codes. For inspection purposes, Permittees
need not inspect facilities with SIC codes 5013, 5014, 5541, 5511 provided that these
facilities have no outside activities or materials that may be exposed to stormwater.
D. "Basin Plan" means the Water Quality Control Plan, Los Angeles Region,
Basin Plan for the Coastal Watersheds of Los Angeles and Ventura Counties, adopted
by the Regional Water Board on June 13, 1994 and subsequent amendments.
E. "Best Management Practices (BMPs)" means practices or physical
devices or systems designed to prevent or reduce pollutant loading from storm water or
non -storm water discharges to receiving waters, or designed to reduce the volume of
storm water or non -storm water discharged to the receiving water. Examples of BMPs
may include, but are not limited to public education and outreach, proper planning of
development projects, proper cleaning of catch basin inlets, and proper sludge- or
waste -handling and disposal, among others.
F. "Biofiltration" means a LID BMP that reduces stormwater pollutant
discharges by intercepting rainfall on vegetative canopy, and through incidental
infiltration and/or evapotranspiration, and filtration. Incidental infiltration is an important
factor in achieving the required pollutant load reduction. Therefore, the term
"biofiltration" as used in this Ordinance is defined to include only systems designed to
facilitate incidental infiltration or achieve the equivalent pollutant reduction as
biofiltration BMPs with an underdrain (subject to approval by the Regional Board's
Executive Officer). Biofiltration BMPs include bioretention systems with an underdrain
and bioswales.
G. "Bioretention" means a LID BMP that reduces stormwater runoff by
intercepting rainfall on vegetative canopy, and through evapotranspiration and
infiltration. The bioretention system typically includes a minimum 2 -foot top layer of a
specified soil and compost mixture underlain by a gravel -filled temporary storage pit dug
into the in-situ soil. As defined in this Ordinance, a bioretention BMP may be designed
with an overflow drain, but may not include an underdrain. When a bioretention BMP is
designed or constructed with an underdrain it is regulated by the NPDES Permit as
biofiltration.
H. "Bioswale" means a LID BMP consisting of a shallow channel lined with
grass or other dense, low -growing vegetation. Bioswales are designed to collect
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stormwater runoff and to achieve a uniform sheet flow through the dense vegetation for
a period of several minutes.
"City" means the City of Rancho Palos Verdes.
J. "Clean Water Act (CWA)" means the Federal Water Pollution Control Act
enacted in 1972, by Public Law 92-500, and amended by the Water Quality Act of 1987.
The Clean Water Act prohibits the discharge of pollutants to Waters of the United States
unless the discharge is in accordance with a NPDES Permit.
K. "Commercial Development" means any development on private land
that is not heavy industrial or residential. The category includes, but is not limited to:
hospitals, laboratories and other medical facilities, educational institutions, recreational
facilities, plant nurseries, car wash facilities; mini -malls and other business complexes,
shopping malls, hotels, office buildings, public warehouses and other light industrial
complexes.
L. "Commercial Malls" means any development on private land comprised
of one or more buildings forming a complex of stores which sells various merchandise,
with interconnecting walkways enabling visitors to easily walk from store to store, along
with parking area(s). A commercial mall includes, but is not limited to: mini -malls, strip
malls, other retail complexes, and enclosed shopping malls or shopping centers.
M. "Construction Activity" means any construction or demolition activity,
clearing, grading, grubbing, or excavation or any other activity that result in land
disturbance. Construction does not include emergency construction activities required to
immediately protect public health and safety or routine maintenance activities required
to maintain the integrity of structures by performing minor repair and restoration work,
maintain the original line and grade, hydraulic capacity, or original purposes of the
facility. See "Routine Maintenance" definition for further explanation. Where clearing,
grading or excavating of underlying soil takes place during a repaving operation, State
General Construction Permit coverage by the State of California General Permit for
Storm Water Discharges Associated with Industrial Activities or for Stormwater
Discharges Associated with Construction Activities is required if more than one acre is
disturbed or the activities are part of a larger plan.
N. "Control" means to minimize, reduce or eliminate by technological, legal,
contractual, or other means, the discharge of pollutants from an activity or activities.
O. "Development" means construction, rehabilitation, redevelopment or
reconstruction of any public or private residential project (whether single-family, multi-
unit or planned unit development); industrial, commercial, retail, and other non-
residential projects, including public agency projects; or mass grading for future
construction. It does not include routine maintenance to maintain original line and grade,
hydraulic capacity, or original purpose of facility, nor does it include emergency
construction activities required to immediately protect public health and safety.
P. "Directly Adjacent" means situated within two hundred feet of the
contiguous zone required for the continued maintenance, function, and structural
stability of the environmentally sensitive area.
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Q. "Director" means the Director of Public Works of the City or the Director's
designee.
R. "Discharge" when used without further qualification of the term means
any release, spill, leak, pump, flow, escape, dumping, or disposal of any liquid, semi-
solid, or solid substance.
S. "Discharge of a Pollutant" means any addition of any pollutant or
combination of pollutants to waters of the United States from any point source, or any
addition of any pollutant or combination of pollutants to the waters of the contiguous
zone or the ocean from any point source other than a vessel or other floating craft that
is being used as a means of transportation. The term "discharge of a pollutant" includes
additions of pollutants into waters of the United States from surface runoff that is
collected or channeled by man; discharges through pipes, sewers, or other
conveyances owned by a state, municipality, or other person that do not lead to a
treatment works; and discharges through pipes, sewers, or other conveyances, leading
into privately owned treatment works.
T. "Discharging Directly" means outflow from a drainage conveyance
system that is composed entirely or predominantly of flows from the subject, property,
development, subdivision, or industrial facility, and not commingled with the flows from
adjacent lands.
U. "Discretionary Project" is defined in the same manner as Section 15357
of the Guidelines for Implementation of the California Environmental Quality Act
contained in Title 14 of the California Code of Regulations, as amended, and means a
project which requires the exercise of judgment or deliberation when the City decides to
approve or disapprove a particular activity, as distinguished from situations where the
City merely has to determine whether there has been conformity with applicable
statutes, ordinances, or regulations.
V. "Disturbed Area" means an area that is altered as a result of clearing,
grading, and/or excavation.
W. "Environmentally Sensitive Area (ESA)" means an area in which plant
or animal life or their habitats are either rare or especially valuable because of their
special nature or role in an ecosystem and which would be easily disturbed or degraded
by human activities and developments (California Public Resources Code Section
30107.5). Areas subject to storm water mitigation requirements are areas designated as
significant ecological areas by the county of Los Angeles (Los Angeles County
Significant Areas Study, Los Angeles County Department of Regional Planning (1976)
and amendments); an area designated as a significant natural area by the California
Department of Fish and Game's Significant Natural Areas Program provided that area
has been field verified by the Department of Fish and Game; an area listed in the Basin
Plan as supporting the Rare, Threatened, or Endangered Species (RARE) beneficial
use; and an area identified by the City as environmentally sensitive as reflected on the
map which is on file in the city's department of planning, building and code enforcement.
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X. "General Construction Activities Storm Water Permit" means the
general NPDES Permit adopted by the State Board which authorizes the discharge of
stormwater from construction activities under certain conditions.
Y. "General Industrial Activities Storm Water Permit" means the general
NPDES Permit adopted by the State Board which authorizes the discharge of
stormwater from certain industrial activities under certain conditions.
Z. "Green Roof" means a LID BMP using planter boxes and vegetation to
intercept rainfall on the roof surface. Rainfall is intercepted by vegetation leaves and
through evapotranspiration. Green roofs may be designed as either a bioretention BMP
or as a biofiltration BMP. To receive credit as a bioretention BMP, the green roof system
planting medium shall be of sufficient depth to provide capacity within the pore space
volume to contain the design storm depth and may not be designed or constructed with
an underdrain.
AA. "Hillside" means a property located in an area with a slope that is 25% or
greater.
BB. "Illicit Connection" means any man-made conveyance that is connected
to the storm drain system without a permit, excluding gutters, roof -drains and other
similar connections. Examples include channels, pipelines, conduits, inlets, or outlets
that are connected directly to the storm drain system.
CC. "Illicit Discharge" means any discharge to the MS4 that is prohibited
under local, state or federal statutes, ordinances, codes or regulations. This includes all
non -storm water discharges, except authorized non -storm water discharges;
conditionally exempt non -storm water discharges; and non -storm water discharges
resulting from natural flows specifically identified in Part IIIA. of the Municipal NPDES
Permit.
DD. "Industrial Park" means land development that is set aside for industrial
development. Industrial parks are usually located close to transport facilities, especially
where more than one transport modalities coincide: highways, railroads, airports, and
navigable rivers. It includes office parks, which have offices and light industry.
EE. "Infiltration" means the downward entry of water into the surface of the
soil.
FF. "Low Impact Development (LID)" consists of building and landscape
features designed to retain or filter stormwater runoff.
GG. "Material" means any substance including, but not limited to: garbage
and debris; lawn clippings, leaves, and other vegetation; biological and fecal waste;
sediment and sludge; oil and grease; gasoline; paints, solvents, cleaners, and any fluid
or solid containing chemicals.
HH. "Municipal NPDES Permit" or "MS4 Permit" means the "Waste
Discharge Requirements for Municipal Separate Storm Sewer System (MS4)
Discharges within the Costal Watersheds of Los Angeles County, except those
Discharges Originating from the City of Long Beach MS4" (Order No. R4-2012-0175,
NPDES Permit No. CAS004001), issued on November 08, 2012, issued by the Los
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13
Angeles Regional California Regional Water Quality Control Board, and any successor
permit to that permit.
II. "Municipal Separate Storm Sewer System (MS4)" or "Municipal
Storm Water System"" means a conveyance or system of conveyances (including
roads with drainage systems, municipal streets, catch basins, curbs, gutters, ditches,
manmade channels, or storm drains):
1. Owned or operated by a State, city, town, borough, county, parish,
district, association, or other public body (created by or pursuant to
State law) having jurisdiction over disposal of sewage, industrial
wastes, stormwater, or other wastes, including special districts
under State law such as a sewer district, flood control district or
drainage district, or similar entity, or an Indian tribe or an authorized
Indian tribal organization, or a designated and approved
management agency under section 208 of the CWA that
discharges to waters of the United States;
2. Designed or used for collecting or conveying stormwater;
3. That is not a combined sewer; and
4. That is not part of a Publicly Owned Treatment Works (POTW) as
defined at 40 C.F.R. Section 122.2. (40 C.F.R. Section
122.26(b)(8)).
JJ. "National Pollutant Discharge Elimination System (NPDES)" means
the national program for issuing, modifying, revoking and reissuing, terminating,
monitoring and enforcing permits, and imposing and enforcing pretreatment
requirements, under CWA Section 307, 402, 318, and 405. The term includes an
"approved program."
KK. "Natural Drainage System" means a drainage system that has not been
improved (e.g., channelized or armored). The clearing or dredging of a natural drainage
system does not cause the system to be classified as an improved drainage system.
LL. "New Development" means land disturbing activities; structural
development, including construction or installation of a building or structure, creation of
impervious surfaces; and land subdivision.
MM. "NPDES Permit" means any waste discharge requirements issued by the
California Regional Water Quality Control Board, Los Angeles Region or the State
Water Resources Control Board as an NPDES Permit pursuant to Water Code Section
13370.
NN. "Parking Lot" means land area or facility for the parking or storage of
motor vehicles used for businesses, commerce, industry, or personal use, with a lot size
of five thousand square feet or more of surface area, or with twenty-five or more parking
spaces.
00. "Pollutant" means those pollutants defined in Section 502(6) of the
federal Clean Water Act (33 U.S.C. Section 1362(6)), or incorporated into California
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Water Code Section 13373. Examples of pollutants include, but are not limited to the
following:
1. Commercial and industrial waste (such as fuels, solvents,
detergents, plastic pellets, hazardous substances, fertilizers,
pesticides, slag, ash, and sludge);
2. Metals such as cadmium, lead, zinc, copper, silver, nickel,
chromium; and non-metals such as phosphorus and arsenic;
3. Petroleum hydrocarbons (such as fuels, lubricants, surfactants,
waste oils, solvents, coolants and grease);
4. Excessive eroded soils, sediment and particulate materials in
amounts which may adversely affect the beneficial use of the
receiving waters, flora or fauna of the state;
5. Animal wastes (such as discharge from confinement facilities,
kennels, pens, recreational facilities, stables, and show facilities);
6. Substances having characteristics such as pH less than six or
greater than nine, or unusual coloration or turbidity, or excessive
levels of fecal coliform, or fecal streptococcus, or enterococcus;
The term "pollutant" shall not include uncontaminated storm water,
potable water or reclaimed water generated by a lawfully permitted
water treatment facility.
The term "pollutant" also shall not include any substance identified
in this definition, if through compliance with the Best Management
Practices available, the discharge of such substance has been
reduced or eliminated to the maximum extent practicable. In an
enforcement action, the burden shall be on the person who is the
subject of such action to establish the reduction or elimination of
the discharge to the maximum extent practicable through
compliance with the Best Management Practices available.
PP. "Project" means all development, redevelopment, and land disturbing
activities. The term is not limited to "Project" as defined under CEQA (Pub. Resources
Code Section 21065).
QQ. "Rainfall Harvest and Use" means a LID BMP system designed to
capture runoff, typically from a roof but can also include runoff capture from elsewhere
within the site, and to provide for temporary storage until the harvested water can be
used for irrigation or non -potable uses. The harvested water may also be used for
potable water uses if the system includes disinfection treatment and is approved for
such use by the local building department. Currently, neither the City nor the County of
Los Angeles Department of Public Health permit harvested rainfall for potable water
use.
RR. "Receiving Water" means "water of the United States" into which waste
and/or pollutants are or may be discharged.
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SS. "Redevelopment" means land -disturbing activity that results in the
creation, addition or replacement of at least five thousand square feet of impervious
surface area on an already developed site for all project categories except single family
residential projects. For existing single family dwelling and accessory structures,
redevelopment is the creation, addition, or replacement of 10,000 square feet or more of
impervious surface area. "Redevelopment" includes, but is not limited to, the following
activities that meet the minimum standards set forth in this definition: (1) the expansion
of a building footprint; (2) the addition or replacement of a structure; (3) the replacement
of an impervious surface that is not part of a routine maintenance activity; and (4) land -
disturbing activities related to structural or impervious surfaces. "Redevelopment" does
not include routine maintenance activities that are conducted to maintain original line
and grade, hydraulic capacity, original purpose of facility or an emergency
redevelopment activity that is required to protect public health and safety.
TT. "Regional Board" means the California Regional Water Quality Control
Board, Los Angeles Region.
UU. "Restaurant" means a facility that sells prepared foods and drinks for
consumption, including stationary lunch counters and refreshment stands selling
prepared foods and drinks for immediate consumption (SIC Code 5812).
VV. "Retail Gasoline Outlet" means any facility engaged in selling gasoline
and lubricating oils.
WW. "Routine Maintenance" includes, but is not limited to projects conducted
to:
1. Maintain the original line and grade, hydraulic capacity, or original
purpose of the facility.
2. Perform as needed restoration work to preserve the original design
grade, integrity and hydraulic capacity of flood control facilities.
3. Carry out road shoulder work, re -grade dirt or gravel roadways and
shoulders and perform ditch cleanouts.
4. Update existing lines* and facilities to comply with applicable
codes, standards, and regulations regardless if such projects result
in increased capacity.
5. Repair leaks
Routine maintenance does not include construction of new** lines
or facilities resulting from compliance with applicable codes,
standards and regulations.
* Update existing lines includes replacing existing lines with new
materials or pipes.
** New lines are those that are not associated with existing facilities
and are not part of a project to update or replace existing lines.
XX. "Runoff" means any runoff including storm water and dry weather flows
from a drainage area that reaches a receiving water body or subsurface. During dry
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weather it is typically comprised of base flow either contaminated with pollutants or
uncontaminated and nuisance flows.
YY. "Significant Ecological Areas (SEAs)" means an area that is
determined to possess an example of biotic resources that cumulatively represent
biological diversity, for the purposes of protecting biotic diversity, as part of the Los
Angeles County General Plan. Areas are designated as SEAs, if they possess one or
more of the following criteria:
1. The habitat of rare, endangered, and threatened plant and animal
species.
2. Biotic communities, vegetative associations, and habitat of plant
and animal species that are either one of a kind, or are restricted in
distribution on a regional basis.
3. Biotic communities, vegetative associations, and habitat of plant
and animal species that are either one of a kind or are restricted in
distribution in Los Angeles County.
4. Habitat that at some point in the life cycle of a species or group of
species, serves as a concentrated breeding, feeding, resting,
migrating grounds and is limited in availability either regionally or
within Los Angeles County.
5. Biotic resources that are of scientific interest because they are
either an extreme in physical/geographical limitations, or represent
an unusual variation in a population or community.
6. Areas important as game species habitat or as fisheries.
7. Areas that would provide for the preservation of relatively
undisturbed examples of natural biotic communities in Los Angeles
County.
8. Special areas.
ZZ. "Site" means land or water area where any "facility or activity" is
physically located or conducted, including adjacent land used in connection with the
facility or activity.
AAA. "Source Control BMP" means any schedule of activities, prohibition of
practices, maintenance procedures, managerial practices or operational practices that
aim to prevent storm water pollution by reducing the potential for contamination at the
source of pollution.
BBB. "Storm Drain System" means any facility or any parts of the facility,
including streets, gutters, conduits, natural or artificial drains, channels and watercourse
that are used for the purpose of collecting, storing, transporting or disposing of
stormwater and are located within the City.
CCC. "Storm Water or Stormwater" means runoff and drainage related to
precipitation events (pursuant to 40 CFR Section 122.26(b)(13); 55 Fed. Reg. 47990,
47995 (Nov. 16, 1990)).
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DDD. "Storm Water Runoff" or "Urban Runoff" means surface water flow
produced by storm and non -storm events. Non -storm events include flow from
residential, commercial or industrial activities involving the use of potable and non -
potable water. When all other factors are constant, runoff increases as the perviousness
of a surface decreases.
EEE. "Structural BMP" means any structural facility designed and constructed
to mitigate the adverse impacts of storm water and urban runoff pollution (e.g. canopy,
structural enclosure). Structural BMPs may include both treatment control BMPs and
source control BMPs.
FFF. "Treatment" means the application of engineered systems that use
physical, chemical, or biological processes to remove pollutants. Such processes
include, but are not limited to, filtration, gravity settling, media adsorption,
biodegradation, biological uptake, chemical oxidation and UV radiation.
GGG. "Treatment Control BMP" means any engineered system designed to
remove pollutants by simple gravity settling of particulate pollutants, filtration, biological
uptake, media adsorption or any other physical, biological, or chemical process.
SECTION 5. Section 13.10.040 of the Rancho Palos Verdes Municipal Code
entitled "Prohibited activities" is hereby repealed in its entirety and shall be replaced with
the following:
"13.10.040 — Prohibited activities.
A. Illicit discharges and connections. No person shall commence, establish,
use, maintain, or continue any illicit connections to the MS4 or any illicit discharges to the
MS4. This prohibition against illicit connections applies to the use, maintenance, or
continuation of any illicit connection, whether that connection was established prior to, or
after the effective date of this chapter.
B. Littering: No person shall throw, deposit, place, leave, maintain, keep or
permit to be thrown, deposited, placed, left, or maintained or kept, any refuse, rubbish,
garbage, or any other discarded or abandoned objects, articles or accumulations, in or
upon any street, alley, sidewalk, storm drain, inlet, catch basin, conduit or drainage
structure, business place, or upon any private plot of land in the city, so that the same
might be or become a pollutant. No person shall throw or deposit litter in any fountain,
pond, lake, stream, or other body of water within the city. This subsection shall not apply
to refuse, rubbish or garbage deposited in containers or other appropriate receptacles
which are placed in designated locations for regular solid waste pick up and disposal.
C. Disposal of Landscape Debris: No person shall intentionally dispose of
leaves, dirt or other landscape debris into a storm drain.
D. Industrial Activities: No person shall conduct any industrial activity in the city
without obtaining all permits required by state or federal law, including a NPDES general
industrial activity storm water permit when required. Persons conducting industrial
activities within the city should refer to the most recent edition of the
"Industrial/Commercial Best Management Practices Handbook", produced and published
by the Storm Water Quality Task Force, for specific guidance on selecting best
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management practices for reducing pollutants in storm water discharges from industrial
activities.
E. Non -storm water discharges. All non -storm water discharges into the MS4
are prohibited unless those flows are:
1. In compliance with a separate NPDES Permit;
2. Pursuant to a discharge exemption by the Regional Board, the
Regional Board's Executive Officer, or the State Water Resources
Control Board;
3. Associated with emergency firefighting activities (i.e., flows
necessary for the protection of life or property);
4. Natural flows as defined in the Municipal NPDES Permit;
5. Conditionally exempt non -storm water discharges as defined in
accordance with the Municipal NPDES Permit; or
6. Authorized as a temporary non -storm water discharge by USEPA
pursuant to sections 104(a) or 104(b) of the Comprehensive
Environmental Response, Compensation, and Liability Act
(CERCLA).
F. Prohibited discharges include, but are not limited to:
1. The discharge of wash waters to the MS4 from commercial auto
washing or when gas stations, auto repair garages, or other type of
automotive service facilities are cleaned;
2. The discharge of water to the MS4 from mobile auto washing, steam
cleaning, mobile carpet cleaning, and other such mobile commercial
and industrial operations;
3. Discharges to the MS4 from areas where repair of machinery and
equipment, including motor vehicles, which are visibly leaking oil,
fluid, or antifreeze, is undertaken;
4. Discharges of runoff to the MS4 from storage areas of materials
containing grease, oil, or other hazardous substances, and
uncovered receptacles containing hazardous materials;
5. Discharges of commercial/residential swimming pool filter backwash
to the MS4;
6. Discharges of runoff from the washing of toxic materials from paved
or unpaved areas to the MS4;
7. Discharges to the MS4 from washing impervious surfaces in
industrial/commercial areas, unless specifically required by the
State's, or the City's, or Los Angeles County's health and safety
codes, or permitted under a separate NPDES permit;
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8. Discharges to the MS4 from the washing out of concrete or cement
laden wash water from concrete trucks, pumps, tools, and
equipment;
9. Discharges to the MS4 of any pesticide, fungicide, or herbicide
banned by the USEPA or the California Department of Pesticide
Regulation or a product registered under the Federal Insecticide,
Fungicide and Rodenticide Act to any waste stream that may
ultimately be released to waters of the United States unless
specifically authorized under an NPDES permit. This requirement is
not applicable to products used for lawn and agricultural purposes.
10. The disposal of hazardous wastes into trash containers used for
municipal trash disposal where such disposal causes or threatens to
cause a direct or indirect discharge to the MS4.
G. Discharges in violation of the Municipal NPDES Permit. Any discharge that
would result in or contribute to a violation of the Municipal NPDES Permit, either
separately or in combination with other discharges, is prohibited. Liability for any such
discharge shall be the responsibility of the person(s) causing or responsible for the
discharge, and such person(s) shall defend, indemnify and hold harmless the city from all
losses, liabilities, claims, or causes of actions in any administrative or judicial action
relating to such discharge."
SECTION 6. A new section 13.10.045, entitled "Exempted Discharges,
Conditionally Exempted Discharges or Designated Discharges", is hereby added to
Chapter 13.10 of the Rancho Palos Verdes Municipal Code to read as follows:
"13.10.045 — Exempted Discharges, Conditionally Exempted Discharges or
Designated Discharges.
Discharges from those activities specifically identified in, or pursuant to, Part
III.A.1-3 of the Municipal NPDES Permit as being exempted discharges, conditionally
exempted discharges, or designated discharges shall not be considered a violation of this
chapter, provided that any such discharges are consistent with Part III.A of the Municipal
NPDES Permit and:
A. Applicable BMPs developed pursuant to the Municipal NPDES Permit are
implemented to minimize any adverse impacts from such identified sources;
B. The discharger meets all notification, reporting and recordkeeping
requirements; and
C. The discharger has conducted all applicable monitoring requirements."
SECTION 7. Section 13.10.050 of the Rancho Palos Verdes Municipal Code
entitled "Requirements for existing properties — Good housekeeping provisions" is hereby
repealed in its entirety and shall be replaced with the following:
"13.10.050 — Requirements for existing properties.
Owners and occupants of property within the city shall comply with the following
requirements:
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A. Septic Waste. No person shall leave, deposit, discharge, dump, or
otherwise expose any chemical or septic waste to precipitation in an area where
discharge to city streets or storm drains system may or does occur.
B. Use of Water. Runoff of water used for irrigation purposes shall be
minimized to the maximum extent practicable. Runoff of water from the permitted washing
down of paved areas shall be minimized to the maximum extent practicable and diverted
so that flow is directed to landscaped areas for infiltration where possible.
C. Storage of Materials, Machinery, and Equipment. Machinery or equipment
that is to be repaired or maintained in areas susceptible to or exposed to storm water,
shall be placed in a manner so that pollutants are not discharged to the municipal storm
water system.
D. Removal and Disposal of Debris and Residue and Other Materials.
1. Non-residential motor vehicle parking lots with more than twenty-five
parking spaces that generate runoff shall be swept regularly or other
equally effective measures will be utilized to remove oil, chemicals,
debris or other polluting materials from such parking lots. Sweeping
and collection of debris is encouraged for trash disposal.
2. Food wastes generated by non-residential food service and food
distribution sources shall be disposed of in a manner so such wastes
are not discharged to the municipal storm water system.
3. Best management practices shall be used in areas exposed to storm
water for the removal and lawful disposal of all fuels, chemicals, fuel
and chemical wastes, animal wastes, garbage, batteries, or other
materials which have potential adverse impacts on water quality.
E. Maintenance of Structural BMPs. Structural BMPs required by the City,
County of Los Angeles, or any state or federal agency shall be properly operated and
maintained, as specified by an approved Storm Water Mitigation Plan (SWMP), or
otherwise determined by the Authorized Enforcement Officer. Records and
documentation of such maintenance shall be provided to the Director upon request."
SECTION 8. Section 13.10.060 of the Rancho Palos Verdes Municipal Code
entitled "Requirements for industrial/commercial and construction activities" is hereby
repealed in its entirety and shall be replaced with the following:
"13.10.060 -- Requirements for industrial/commercial and construction activities.
A. Each industrial discharger, discharger associated with construction activity,
or other discharger described in any general NPDES permit addressing such discharges,
as may be issued by the U.S. Environmental Protection Agency, the State Water
Resources Control Board, or the Regional Board, shall comply with all requirements of
such permit and the provisions of this chapter. Each discharger identified in an individual
NPDES permit shall comply with and undertake all activities required by such permit.
Proof of compliance with any such NPDES permit may be required in a form acceptable
to the Authorized Enforcement Officer, or designated representative, prior to the issuance
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of any grading, building or occupancy permits, or any other type of permit or license
issued by the city.
B. Non -storm water discharges to the MS4 from industrial, commercial, or
construction activities in violation of any applicable NPDES permit or the provisions of this
chapter are prohibited.
C. Industrial and commercial dischargers and dischargers associated with
construction activities shall implement effective BMPs, including source control BMPs, in
accordance with Table 10 of Part VI.D.6.f of the Municipal NPDES Permit unless a
particular pollutant generating activity does not occur on a facility's site."
SECTION 9. Section 13.10.065 of the Rancho Palos Verdes Municipal Code
entitled "Standard Urban Storm Water Mitigation Plan (SUSMP) requirements for new
development and redevelopment projects" is hereby repealed in its entirety and shall be
replaced with the following:
"13.10.065 — LOW IMPACT DEVELOPMENT REQUIREMENTS FOR NEW
DEVELOPMENT AND REDEVELOPMENT.
A. Objective. The provisions of this Section establish requirements for
construction activities and facility operations of Development and Redevelopment
projects to comply with the current MS4 Permit (Order No. R4-2012-0175), to lessen the
water quality impacts of development by using smart growth practices, and integrate
LID practices and standards for stormwater pollution mitigation through means of
infiltration, evapotranspiration, biofiltration, and rainfall harvest and use. LID shall be
inclusive of new development and/or redevelopment requirements.
B. Scope. This Section contains requirements for stormwater pollution
control measures in Development and Redevelopment projects and authorizes the City
to further define and adopt stormwater pollution control measures, and to develop LID
principles and requirements, including but not limited to the objectives and
specifications for integration of LID strategies. Except as otherwise provided herein, the
City shall administer, implement and enforce the provisions of this Section.
C. Applicability. This section applies to the following New Development and
Redevelopment Projects which are subject to City conditioning and approval for the
design and implementation of post -construction controls and other BMPs to mitigate
stormwater pollution, prior to completion of the project(s), as follows:
1. New Development Projects.
a. All development projects, including all single family homes,
equal to 1 acre or greater of disturbed area that adds more than
10,000 square feet of impervious surface area.
b. Industrial parks 10,000 square feet or more of surface area.
c. Commercial malls 10,000 square feet or more of surface area.
d. Retail gasoline outlets with 5,000 square feet or more of surface
area.
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e. Restaurants (Standard Industrial Classification (SIC) of 5812)
with 5,000 square feet or more of surface area.
f. Parking lots with 5,000 square feet or more of impervious
surface area, or with 25 or more parking spaces.
g. Street and road construction of 10,000 square feet or more of
impervious surface area (see Section D.2). Street and road
construction applies to standalone streets, roads, highways, and
freeway projects, and also applies to streets within larger
projects.
h. Automotive service facilities (Standard Industrial Classification
(SIC) of 5013, 5014, 5511, 5541, 7532-7534 and 7536-7539)
5,000 square feet or more of surface area.
Projects located in or directly adjacent to, or discharging directly
to an Significant Ecological Area (SEA), where the development
will:
(1) Discharge stormwater runoff that is likely to impact a
sensitive biological species or habitat; and
(2) Create 2,500 square feet or more of impervious
surface area
New Single-family hillside homes that do not meet the criteria
paragraph (a) in this Section shall implement the measures of
Section D.1.
2. Redevelopment Projects
a. Land disturbing activity that results in the creation or addition or
replacement of 5,000 square feet or more of impervious surface
area on an already developed site for categories identified in
Section C.1.
b. Where Redevelopment results in an alteration to more than fifty
percent of impervious surfaces of a previously existing
development, and the existing development was not subject to
post -construction stormwater quality control requirements, the
entire project must be mitigated.
c. Where Redevelopment results in an alteration of less than fifty
percent of impervious surfaces of a previously existing
development, and the existing development was not subject to
post -construction stormwater quality control requirements, only
the alteration must be mitigated, and not the entire
development.
d. Redevelopment does not include routine maintenance activities
that are conducted to maintain original line and grade, hydraulic
capacity, original purpose of facility or emergency
redevelopment activity required to protect public health and
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safety. Impervious surface replacement, such as the
reconstruction of parking lots and roadways which does not
disturb additional area and maintains the original grade and
alignment, is considered a routine maintenance activity.
Redevelopment does not include the repaving of existing roads
to maintain original line and grade.
e. Existing single-family dwelling and accessory structures are
exempt from the Redevelopment requirements unless such
projects create, add, or replace 10,000 square feet of
impervious surface area.
D. Specific Requirements.
1. New Single -Family Hillside Homes. The construction of a new single-
family hillside homes that do not meet the criteria of Section C.1.a are
exempt from the requirements of Section D.3 but shall include
mitigation measures to:
a. Conserve natural areas;
b. Protect slopes and channels;
c. Provide storm drain system stenciling and signage;
d. Divert roof runoff to vegetated areas before discharge unless
the diversion would result in slope instability; and
e. Direct surface flow to vegetated areas before discharge, unless
the diversion would result in slope instability.
2. Street and road construction of 10,000 square feet or more of
impervious surface are exempt from the New Development
/Redevelopment Project Performance Criteria of Part VI.D.7.c of the
MS4 Permit but shall follow the City's Green Streets Manual to the
maximum extent practicable, consistent with the City's Green Streets
Policy.
3. New Development and Redevelopment Projects. Unless otherwise
exempted in this chapter or in the MS4 Permit, the site for every New
Development and Redevelopment Project shall comply with Part
VI.D.7.c of the MS4 Permit and be designed to control pollutants,
pollutant loads, and runoff volume to the maximum extent feasible by
minimizing impervious surface area and controlling runoff from
impervious surfaces through infiltration, evapotranspiration,
bioretention and/or non -potable rainfall harvest and use in accordance
with the requirements set forth in the MS4 Permit. The project
applicant shall prepare a Storm Water Mitigation Plan which
implements set LID standards and practices for stormwater pollution
mitigation, provides documentation to demonstrate compliance with the
MS4 Permit on the plans and permit application submitted to the City,
and complies with the following:
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4. Retain stormwater runoff onsite for the Stormwater Quality Design
Volume (SWQDv) defined as the runoff from:
a. The 85th percentile 24-hour runoff event as determined from the
Los Angeles County 85th percentile precipitation isohyetal map;
or
b. The volume of runoff produced from a 0.75 inch, 24-hour rain
event, whichever is greater.
5. Minimize hydromodification impacts to natural drainage systems as
defined in The NPDES Permit.
E. Technical Infeasibility.
Some relief, as outlined later in this Section, from the MS4 Permit (Part
VI.D.7.c) requirements may be granted for technical infeasibility. To
demonstrate technical infeasibility, the project applicant must
demonstrate that the project cannot reliably retain 100 percent of the
SWQDv on-site, even with the maximum application of green roofs and
rainwater harvest and use, and that compliance with the applicable
post -construction requirements would be technically infeasible by
submitting a site-specific hydrologic and/or design analysis conducted
and endorsed by a registered professional engineer, geologist,
architect, and/or landscape architect. Technical infeasibility may result
from conditions including the following:
2. The infiltration rate of saturated in-situ soils is less than 0.3 inch per
hour and it is not technically feasible to amend the in-situ soils to attain
an infiltration rate necessary to achieve reliable performance of
infiltration or bioretention BMPs in retaining the SWQDv onsite.
3. Locations where seasonal high groundwater is within five to ten feet of
surface grade;
4. Locations within 100 feet of a groundwater well used for drinking water;
5. Brownfield development sites or other locations where pollutant
mobilization is a documented concern;
6. Locations with potential geotechnical hazards;
7. Smart growth and infill or redevelopment locations where the density
and/ or nature of the project would create significant difficulty for
compliance with the onsite volume retention requirement.
8. If partial or complete onsite retention is technically infeasible, the
project Site may biofilter 1.5 times the portion of the remaining SWQDv
that is not reliably retained onsite. Biofiltration BMPs must adhere to
the design specifications provided in the MS4 Permit (Order No. R4-
2012-0175).
9. The remaining SWQDv that cannot be retained or biofiltered onsite
must be treated onsite to reduce pollutant loading. BMPs must be
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selected and designed to meet pollutant -specific benchmarks as
required by the MS4 Permit. Flow-through BMPs may be used to treat
the remaining SWQDv and must be sized based on a rainfall intensity
of:
a. 0.2 inches per hour, or
b. The one year, one-hour rainfall intensity as determined from the
most recent Los Angeles County isohyetal map, whichever is
greater.
F. Exemptions from LID Requirements. The provisions of this Chapter do
not apply to any of the following:
1. A Development involving only emergency Construction Activity
required to immediately protect public health and safety;
2. Infrastructure projects within the public right-of-way, excluding street
and road construction of 10,000 square feet or more of impervious
surface;
3. A Development or Redevelopment involving only activity related to
utility services (storm drain, sewer, gas, water, cable, or electricity
services) on private property;
4. A Development or Redevelopment involving only resurfacing and/or re -
striping of permitted parking lots, where the original line and grade,
hydraulic capacity, and original purpose of the facility is maintained;
5. A project not requiring a City building, grading, demolition or other
permit for Construction Activity.
G. City Review and Approval. Prior to the issuance of a building permit for a
New Development or Redevelopment Project, the City shall evaluate the proposed
project using the MS4 Permit, and erosion and grading requirements of the City Building
Official or Authorized Enforcement Officer to determine (i) its potential to generate the
flow of Pollutants into the MS4 after construction; and (ii) how well the Storm Water
Mitigation Plan for the proposed project meets the goals of this Chapter. Each plan will
be evaluated on its own merits according to the particular characteristics of the project
and the site to be developed. Based upon the review, the City may impose conditions
upon the issuance of the building permit, in addition to any required by the State
Construction General Permit for the project, in order to minimize the flow of Pollutants
into the MS4.
H. Issuance of Discretionary Permits. No discretionary permit may be issued
for any new development or redevelopment project identified in this section until the
Authorized Enforcement Officer confirms that the project plans comply with the
applicable LID requirements. Where redevelopment results in an alteration to more
than 50 percent of impervious surfaces of a previously existing development, and the
existing development was not subject to post -development storm water quality control
requirements, the entire project must be mitigated. Where redevelopment results in an
alteration to less than 50 percent of impervious surfaces of a previously existing
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development, and the existing development was not subject to post -development storm
water quality control requirements, only the alteration must be mitigated, and not the
entire development.
I. Issuance of Certificates of Occupancy. As a condition for issuing a
certificate of occupancy for a project subject to this chapter, the Director shall require
facility operators or owners to build all BMPs that are shown on the approved project
plans and to submit an owner signed certification statement stating that the site and all
LID BMPs will be maintained in compliance with the Storm Water Mitigation Plan and
other applicable regulatory requirements.
Transfer of Properties Subject to Requirement for Maintenance of BMPs.
The transfer or lease of a property subject to a requirement for
maintenance of BMPs shall include conditions requiring the transferee
and its successors and assigns to either: (a) assume responsibility for
maintenance of any existing BMP, or (b) to replace an existing BMP
with new control measures or BMPs meeting the then current
standards of the City and the Municipal NPDES Permit. Such
requirement shall be included in any sale or lease agreement or deed
for such property. The condition of transfer shall include a provision
that the successor property owner or lessee conduct maintenance
inspections of all BMPs at least once a year and retain proof of
inspection.
2. For residential properties where the LID BMPs are located within a
common area, which will be maintained by a homeowner's association,
language regarding the responsibility for maintenance shall be
included in the project's conditions, covenants and restrictions
(CC&Rs). Printed educational materials will be required to accompany
the first deed transfer to highlight the existence of the requirement and
to provide information on what storm water management facilities are
present, signs that maintenance is needed, and how the necessary
maintenance can be performed. The transfer of this information shall
also be required with any subsequent sale of the property.
3. If LID BMPs are located within an area proposed for dedication to a
public agency, they will be the responsibility of the developer until the
dedication is accepted."
SECTION 10. Section 13.10.070 of the Rancho Palos Verdes Municipal Code
entitled "Enforcement" is hereby repealed in its entirety and shall be replaced with the
following:
A. Violations Deemed a Public Nuisance.
A violation of any provision of this chapter is declared to be a public
nuisance, and the city attorney is authorized to abate such violation by
means of a civil action in addition to whatever other remedies are
available to the city under this code and other applicable laws, rules or
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27
regulations. Additionally, the following conditions shall be considered a
public nuisance:
c. Any failure to comply with any applicable requirement of this
Chapter or the Municipal NPDES Permit; or
d. Any false certification or verification, or any failure to comply
with a certification or verification provided by a project applicant
or the applicant's successor in interest; or
e. Any failure to properly operate and maintain any structural or
treatment control BMP on a property in accordance with an
approved Storm Water Mitigation Plan, this Chapter, or the
Municipal NPDES Permit.
2. The above listed conditions are hereby determined to be a threat to the
public health, safety and welfare, are declared and deemed a public
nuisance, and may be abated or restored by any Authorized
Enforcement Officer, and a civil or criminal action to abate, enjoin or
otherwise compel the cessation of such nuisance may be brought by
the city attorney.
3. The cost of such abatement and restoration shall be borne by the
owner of the property and the cost thereof shall be invoiced to the
owner of the property, as provided by law or ordinance for the recovery
of nuisance abatement costs. If any violation of this chapter constitutes
a seasonal and recurrent nuisance, the Authorized Enforcement
Officer shall so declare. The failure of any person to take appropriate
annual precautions to prevent storm water pollution after written notice
of a determination under this section shall constitute a public nuisance
and a violation of this chapter.
B. Inspections.
Whenever necessary to make an inspection to enforce any of the
provisions of this section, or whenever an Authorized Enforcement
Officer has reasonable cause to believe that there exists on any
construction site any condition which constitutes a violation of the
provisions of this section, the Authorized Enforcement Officer may,
upon consent or upon obtaining an inspection warrant, enter such
construction site at all reasonable times to inspect the same or perform
any duty imposed upon the Officer by this section.
2. Routine or area inspections shall be based upon such reasonable
selection process as may be deemed necessary to carry out the
objectives of this chapter, including, but not limited to, random
sampling and/or sampling in areas with evidence of storm water
contamination, discharges of non-stormwater to the MS4, discharges
which are not pursuant to an NPDES permit, or similar factors.
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V
•
3. Right to Inspect. Prior to commencing any inspection as herein below
authorized, the Authorized Enforcement Officer shall obtain either the
consent of the owner, his/her authorized representative or the
occupant of the property or shall obtain an administrative inspection
warrant or criminal search warrant.
4. Entry to Inspect. The Authorized Enforcement Officer may enter
property to investigate the source of any discharge to any public street,
inlet, gutter, storm drain or any other part of the MS4 located within the
jurisdiction of the City.
5. Compliance Assessments. The Authorized Enforcement Officer may
inspect property for the purpose of verifying compliance with this
chapter, including but not limited to (a) identifying products produced,
processes conducted, chemicals used and materials stored on or
contained within the property; (b) identifying point(s) of discharge of all
wastewater, process water systems and pollutants; (c) investigating
the natural slope at the location, including drainage patterns and man-
made conveyance systems; (d) establishing the location of all points of
discharge from the property, whether by surface runoff or through a
storm drain system; (e) locating any illicit connection or the source of
prohibited discharge; (f) evaluating compliance with any permit issued
relating to a discharge to the stormwater drainage system.
6. Portable Equipment. For purposes of verifying compliance with this
chapter, the Authorized Enforcement Officer may inspect any vehicle,
truck, trailer, tank truck or other mobile equipment.
7. Records Review. The Authorized Enforcement Officer may inspect all
records of the owner or occupant of property relating to chemicals or
processes presently or previously occurring on-site, including material
and/or chemical inventories, facilities maps or schematics and
diagrams, material safety data sheets, hazardous waste manifests,
business plans, pollution prevention plans, state general permits,
stormwater pollution prevention plans, monitoring program plans and
any other record(s) relating to illicit connections, prohibited discharges,
or any other source of contribution or potential contribution of
pollutants to the stormwater drainage system.
8. Sample and Test. The Authorized Enforcement Officer may inspect,
sample and test any area runoff, soils area (including groundwater
testing), process discharge, materials within any waste storage area
(including any container contents), and/or treatment system discharge
for the purpose of determining the potential for contribution of
pollutants to the stormwater drainage system. The Authorized
Enforcement Officer may investigate the integrity of all storm drain and
sanitary sewer systems, any legal nonconforming connection or other
pipelines on the property using appropriate tests, including but not
limited to smoke and dye tests or video surveys. The Authorized
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Enforcement Officer may take photographs or video tape, make
measurements or drawings, and create any other record reasonably
necessary to document conditions on the property.
9. Monitoring. The Authorized Enforcement Officer may erect and
maintain monitoring devices for the purpose of measuring or sampling
any discharge or potential source of discharge to the stormwater
drainage system.
10. Test Results. The owner or occupant of property subject to inspection
shall, on submission of a written request, receive copies of all
monitoring and test results conducted by the Authorized Enforcement
Officer.
C. Concealment. Causing, permitting, aiding, abetting, or concealing a
violation of any provision of this chapter shall constitute a violation of such provision.
D. Civil Actions. In addition to any other remedies provided in this section,
any violation of this section may be enforced by civil action brought by the City. In any
such action, the City may seek, and the court shall grant, as appropriate, any or all of
the following remedies:
1. A temporary and/or permanent injunction.
2. Assessment of the violator for the costs of any investigation,
inspection, or monitoring survey which led to the establishment of the
violation, and for the reasonable costs of preparing and bringing legal
action under this subsection.
3. Costs incurred in removing, correcting, or terminating the adverse
effects resulting from violation.
4. Compensatory damages for loss or destruction to water quality,
wildlife, fish and aquatic life.
E. Administrative Enforcement Powers. In addition to the other enforcement
powers and remedies established by this chapter, any Authorized Enforcement Officer
has the authority to utilize the following administrative remedies:
Cease and Desist Orders. When an Authorized Enforcement Officer
finds that a discharge has taken place or is likely to take place in
violation of this chapter, the Officer may issue an order to cease and
desist such discharge, or practice, or operation likely to cause such
discharge and direct that those persons not complying shall: (a)
comply with the requirement, (b) comply with a time schedule for
compliance, and (c) take appropriate remedial or preventive action to
prevent the violation from recurring.
2. Notice to Clean. Whenever an Authorized Enforcement Officer finds
any oil, earth, debris, grass, weeds, dead trees, tin cans, rubbish,
refuse, waste or any other material of any kind, in or upon the sidewalk
abutting or adjoining any parcel of land, or upon any parcel of land or
grounds, which may result in pollutants entering the municipal storm
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30
drain system or a non -storm water discharge to the storm drain
system, he or she may give notice to the owner or occupant of the
adjacent property to remove such oil, earth, debris, grass, weeds, dead
trees, tin cans, rubbish, refuse, waste or other material, in any manner
that he or she may reasonably provide. The recipient of such notice
shall undertake the activities as described in the notice.
F. Penalties. Violation of this section shall be punishable as provided in
Section 1.08.010 of this Code. Each day that a violation continues shall constitute a
separate offense.
G. Permit Revocation. To the extent the City makes a provision of this
chapter or any identified BMP a condition of approval to the issuance of a permit or
license, any person in violation of such condition is subject to the permit revocation
procedures set forth in this Code.
H. Remedies. Remedies under this chapter are in addition to and do not
supersede or limit any and all other remedies, civil or criminal. The remedies provided
for herein shall be cumulative and not exclusive."
SECTION 11. A new section 13.10.080, entitled "Fees", is hereby added to
Chapter 13.10 of the Rancho Palos Verdes Municipal Code to read as follows:
"13.10.080 — Fees.
Fees for plan reviews, inspections, violations, corrections, and tasks associated
with this chapter may be established by resolution of the City Council."
SECTION 12. If any section, subsection, subdivision, sentence, clause,
phrase, or portion of this ordinance or the application thereof to any person or place, is
for any reason held to be invalid or unconstitutional by the decision of any court of
competent jurisdiction, such decision shall not affect the validity of the remainder of this
ordinance. The City Council hereby declares that it would have adopted this ordinance,
and each and every section, subsection, subdivision, sentence, clause, phrase, or
portion thereof, irrespective of the fact that any one or more sections, subsections,
subdivisions, sentences, clauses, phrases, or portions thereof be declared invalid or
unconstitutional.
SECTION 13. The City Clerk shall certify to the passage of this ordinance
and shall cause same to be published pursuant to state law within fifteen (15) days after
its passage, and this ordinance shall become effective thirty (30) days after its passage.
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PASSED, APPROVED, AND ADOPTED at a regular meeting of the City Council of the
City of Rancho Palos Verdes, California, on this 21St day of April 2015.
Jim Knight
IMAMe]
ATTEST:
Carla Morreale
CITY CLERK
STATE OF CALIFORNIA
COUNTY OF LOS ANGELES
CITY OF RANCHO PALOS VERDES
I, Carla Morreale, City Clerk of the City of Rancho Palos Verdes, California,
hereby certify that Ordinance No. was introduced at a regular meeting of the
City Council of the City of Rancho Palos Verdes held on April 7, 2015, and thereafter was
adopted by the City Council at a regular meeting held on April 21, 2015, and that the
same was adopted by the following roll call vote:
AYES:
NOES:
ABSENT:
ABSTAIN:
Page 26 of 26
CITY CLERK
32
ATTACHMENT B
RESOLUTION NO. 2015-
A RESOLUTION OF THE CITY COUNCIL OF THE CITY OF RANCHO PALOS
VERDES, CALIFORNIA, APPROVING A GREEN STREETS POLICY
THE CITY COUNCIL OF THE CITY OF RANCHO PALOS VERDES,
CALIFORNIA, HEREBY RESOLVES, DETERMINES AND ORDERS AS
FOLLOWS:
SECTION 1: The Municipal Separate Storm Sewer System (MS4) Permit
(Order No. R-2012-0175) was adopted by the California Regional Water Quality Control
Board, Los Angeles Region on November 8, 2012. Municipalities electing to prepare a
Watershed Management Program or an Enhanced Watershed Management Program
under this Permit are required to demonstrate that Green Street policies are in place that
specify the use of green street strategies for transportation corridors.
SECTION 2: Green Streets are enhancements to street and road projects
to improve the quality of storm water and urban runoff through the implementation of
infiltration, bio -treatment, xeriscaping parkways and tree lined streets.
SECTION 3: The City Council of the City of Rancho Palos Verdes,
California, hereby adopts the City of Rancho Palos Verdes Green Streets Manual shown
in Exhibit "A," attached hereto and incorporated by reference, and directs the Director of
Public Works, or his designee, to implement green streets strategies for transportation
corridors as described in the City of Rancho Palos Verdes Green Streets Manual to the
maximum extent practicable.
SECTION 4: Routine maintenance including but not limited to: slurry seals,
grind and overlay and reconstruction to maintain original line are grade are excluded from
the Green Street Policy.
PASSED, APPROVED, AND ADOPTED on April 7, 2015.
AYES:
1,0191:01
ABSENT:
ABSTAIN
Jim Knight
MAYOR
ATTEST:
Carla Morreale
CITY CLERK
33
STATE OF CALIFORNIA
COUNTY OF LOS ANGELES ) ss.
M11111 WAS] 0 :41-111 IM MM W11111 W -Al 1110MYJ 21 MQ 41.9
I, Carla Morreale, City Clerk of the City of Rancho Palos Verdes, California,
hereby certify that the above Resolution No. 2015- was duly and regularly passed
and adopted by the said City Council at a regular meeting thereof held on April 7, 2015.
Carla Morreale
CITY CLERK
34
EXHIBIT A — City of Rancho Palos Verdes Green Streets Manual
35
Rancho Palos Verdes
Green Streets Manual
April 2015
LIqRWHoFMos\/ERDEs
36
Green Streets Manual
April 2015
Prepared for:
City of Rancho Palos Verdes
Department of Public Works
30940 Hawthorne Blvd.
Rancho Palos Verdes, CA 90275
(310) 544-5252
37
Green Streets Manual
TABLE OF CONTENTS
Section1— Introduction................................................................................................................................1
1.1 What are Green Streets?..............................................................................................................1
1.2 Why are Green Streets being required?.......................................................................................1
1.3 Planning and Development...........................................................................................................3
1.3.1 Site Considerations...............................................................................................................
3
1.3.2 Design Considerations...........................................................................................................4
1.3.3 BMP Sizing for Applicable Green Streets Projects................................................................4
1.3.4 Alternative Compliance Options for Applicable Green Streets Projects ..............................5
1.3.5 Infiltration Considerations....................................................................................................5
Section2 — Infiltration...................................................................................................................................9
2.1 Infiltration Trenches and Dry Wells..............................................................................................9
2.2 Rain Gardens...............................................................................................................................10
2.3 Permeable Pavement..................................................................................................................11
Section3 — Biotreatment............................................................................................................................13
3.1 Bioretention................................................................................................................................13
3.2 Flow -Through Planters................................................................................................................14
3.3 Vegetated Swales........................................................................................................................15
3.4 Vegetated Buffer Strips...............................................................................................................16
Section4 — Treatment BMPs.......................................................................................................................17
4.1 sand Filters & Storm Drain Inlet Protections..............................................................................17
Section5 — Street Trees..............................................................................................................................19
5.1 Street Trees.................................................................................................................................19
Section6 — Definitions................................................................................................................................
20
Section7 — References................................................................................................................................
20
City of Rancho Palos Verdes Table of Contents April 2015
38
Green Streets Manual
SECTION 1 - INTRODUCTION
1.1 WHAT ARE GREEN STREETS?
Roads present many opportunities for green infrastructure application. One principle of green
infrastructure involves reducing and treating stormwater close to its source. Urban transportation right-
of-ways integrated with green techniques are often called "green streets." Green streets provide source
controls for stormwater runoff and pollutant loads. In addition, green infrastructure approaches
complement street facility upgrades, street aesthetic improvements, and urban tree canopy efforts that
also make use of the right-of-way and allow it to achieve multiple goals and benefits. Using the right-of-
way for treatment of stormwater runoff links green with grey infrastructure by making use of the
engineered conveyance of roads and providing connections to conveyance systems when needed.
Green streets are beneficial for new road construction and retrofits. They can provide substantial
economic benefits when used in transportation applications. Coordinating green infrastructure
installation with broader transportation improvements can reduce the cost of stormwater management
by including it within larger infrastructure improvements. A large municipal concern regarding green
infrastructure use is maintenance access; using roads and right-of-ways as locations for green
infrastructure not only addresses a significant pollutant source, but also alleviates access and
maintenance concerns by using public space. Also, right-of-way installations allow for easy public
maintenance.
Green streets can incorporate a wide variety of design elements including street trees, permeable
pavements, bioretention, and swales. Although the design and appearance of green streets will vary, the
functional goals are the same; provide source control of stormwater, limit its transport and pollutant
conveyance to the collection system, restore pre -development hydrology to the maximum extent
practicable, and provide environmentally enhanced roads. Successful application of green techniques
will encourage soil and vegetation contact and infiltration and retention of stormwater.
1.2 WHY ARE GREEN STREETS BEING REQUIRED?
This Green Streets Manual provides guidance to comply with the Municipal Separate Storm Sewer
System (MS4) Permit (Order Number R4-2012-0175), and any subsequent permit, which requires that
jurisdictions in Los Angeles County reduce contaminants in runoff to improve water quality in
waterways. These requirements stem from the National Pollutant Discharge Elimination System (NPDES)
requirements of the Clean Water Act (CWA).
The MS4 Permit requires Green Streets strategies to be implemented for transportation corridors.
Transportation corridors represent a large percentage of the impervious area within Los Angeles and
therefore generate a substantial amount of runoff from storm events. The altered flow regime from
traditional roadways, increased runoff volume, and high runoff peak flows, are damaging to the
environment and a risk to property downstream.
Traditionally, street design has focused on removing water from the street as quickly as possible and
transferring it to storm drains, channels, and water bodies. Stormwater runoff can contain bacteria and
other pollutants, and is thereby regulated at the state and local level (refer to Table 1 for a list of
pollutants typical of roads). Green Streets will help to transform the design of streets from the
conventional method of moving water off-site as quickly as possible to a method of storing and treating
water on-site for a cleaner discharge into the waters of the U.S.
City of Rancho Palos Verdes Page 1 April 2015
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Green Streets Manual
Street and road construction applies to major arterials, state routes, highways, or rail lines used for the
movement of people or goods by means of bus services, trucks, and vehicles, and transportation
corridors within larger projects. Projects which are required to follow this Green Streets Guidance
Manual include the following:
1. Street and road construction of 10,000 square feet or more of impervious surface area.
2. Street and road redevelopment resulting in the creation or addition or replacement of 5,000
square feet or more of impervious surface area on an already developed site. Redevelopment
does not include routine maintenance activities that are conducted to maintain original line and
grade, hydraulic capacity, original purpose of facility or emergency redevelopment activity
required to protect public health and safety. Impervious surface replacement, such as the
reconstruction of parking lots and roadways which does not disturb additional area and
maintains the original grade and alignment, is considered a routine maintenance activity.
Redevelopment does not include the repaving of existing roads to maintain original line and
grade.
Table 1: Examples of Stormwater Pollutants Typical of Roads (Managing Wet Weather with Green Infrastructure Municipal
Handbook: Green Streets, 2008).
Pollutant
Source
Effects
Trash
Littering
Physical damage to aquatic animals and fish,
release of poisonous substances
Increased turbidity, increased transport of soil
Sediment/solids
Construction, unpaved areas
bound pollutants, negative effects on aquatic
organisms reproduction and function
Metals (Copper, Zinc, Lead,
Vehicle brake pads, vehicle tires, motor oil, vehicle
Toxic to aquatic organisms and can accumulate in
Arsenic)
emissions and engines, vehicle emissions, brake
sediments and fish tissues
linings, automotive fluids
Organics associated with
Vehicle emissions, automotive fluids, gas stations
Toxic to aquatic organisms
petroleum (e.g., PAHs)
Vehicle emissions, atmospheric deposition,
Promotes eutrophication and depleted dissolved
Nutrients
fertilizers, leaf shed
oxygen concentrations
Bacteria
Animal traffic
Creates a harmful environment for humans and
aquatic life
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Green Streets Manual
1.3 PLANNING AND DEVELOPMENT
Ideally, a site would be designed to capture and use or infiltrate the entire runoff volume of a storm,
however site and design constraints make it difficult to achieve that goal. This Green Streets Manual is
designed to provide guidance with BMP selection based on site constraints typical to street design.
Streetscape geometry, topography, and climate determine the types of controls that can be
implemented. The initial step in selecting a stormwater tool is determining the available open space and
constraints. Stormwater controls should be selected using the hierarchy represented in Figure 1, the site
guidelines represented in Table 2, and the location opportunities listed in Table 3.
1.3.1 Site Considerations
Specific elements which should be given special consideration in the site assessment process for
applicable Green Streets include:
Ownership of land adjacent to right of ways. The opportunity to provide stormwater treatment
may depend on the ownership of land adjacent to the right-of-way. Acquisition of additional
right-of-way and/or access easements may be more feasible if land bordering the project is
owned by relatively few land owners.
Location of existing utilities. The location of existing storm drainage utilities can influence the
opportunities for Green Streets infrastructure. For example, stormwater planters can be
designed to overflow along the curb -line to an existing storm drain inlet, thereby avoiding the
infrastructure costs associated with an additional inlet. The location of other utilities may limit
the allowable placement of BMPs to only those areas where a clear pathway to the storm drain
exists.
Grade differential between road surface and storm drain system. Some BMPs require more
head from inlet to outlet than others; therefore, allowable head drop may be an important
consideration in BMP selection. Storm drain elevations may be constrained by a variety of
factors in a roadway project (utility crossings, outfall elevations, etc.) that cannot be overcome
and may override stormwater management considerations.
Longitudinal slope. The suite of BMPs which may be installed on steeper road sections is more
limited. Specifically, permeable pavement and swales are more suitable for gentle grades. Other
BMPs may be more readily terraced to be used on steeper slopes. Infiltration should not be
considered for slopes greater than 10%.
Soil suitability. Infiltration BMPs require specific types of soil. The site assessment should
determine the type of soils on the site and the infiltration rate of the soils if infiltration BMPs are
proposed.
Land subsidence potential. If infiltration is proposed, the increased potential for land
subsidence must be considered and addressed in a geotechnical investigation.
Potential access opportunities. A significant concern with installation of BMPs in major right of
ways is the ability to safely access the BMPs for maintenance considering traffic hazards. Vehicle
travel lanes and specific areas potentially hazardous for maintenance crews should be identified
during the site assessment. The Green Streets WQMP should provide subsequent steps to avoid
placing BMPs in the identified hazardous areas.
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Green Streets Manual
1.3.2 Design Considerations
The drainage patterns of the project should be developed so that drainage can be routed to areas with
BMP opportunities before entering storm drains. For example, if a median strip is present, a reverse
crown should be considered, where allowed, so that stormwater can drain to a median swale. Likewise,
standard peak -flow curb inlets should be located downstream of areas with potential for stormwater
planters so that water can first flow into the planter, and then overflow to the downstream inlet if
capacity of the planter is exceeded. It is more difficult to apply green infrastructure after water has
entered the storm drain.
Green Streets projects are not required to treat off-site runoff; however treatment of comingled off-site
runoff may be used to off -set the inability to treat areas within the project for which significant
constraints prevent the ability to provide treatment.
Applicable Green Streets projects should apply the following site design measures to the maximum
extent practicable and as specified in the local permitting agency's codes:
Minimize street width where feasible while maintaining traffic flow and public safety.
Add tree canopy by planting or preserving trees/shrubs.
Use porous pavement or pavers for low traffic roadways, on -street parking, shoulders or
sidewalks.
Integrate traffic calming measures in the form of bioretention curb extensions.
1.3.3 BMP Sizing for Applicable Green Streets Projects
An 85`h percentile standard design storm should be used to determine the appropriate size, slope, and
materials of each facility. After identifying the appropriate stormwater facilities for a site, an integrated
approach using several BMPs is encouraged. To increase water quality and functional hydrologic
benefits, several stormwater management BMPs can be used in succession. This is called a treatment
train approach. The control measures should be designed using available topography to take advantage
of gravity for conveyance to and through each facility. All Green Streets designs must be based off of a
published design standard.
The following steps should be used to size BMPs for applicable Green Streets projects:
1. Delineate drainage areas tributary to BMP locations and compute imperviousness.
2. Look up the recommended sizing method for the BMP selected in each drainage area and
calculate target sizing criteria.
3. Design BMPs per a published design standard.
4. Attempt to provide the calculated sizing criteria for the selected BMPs.
5. If sizing criteria cannot be achieved, document the constraints that override the application of
BMPs and provide the largest portion of the sizing criteria that can be reasonably provided given
constraints. If BMPs cannot be sized to provide the calculated volume for the tributary area, it is
still essential to design the BMP inlet, energy dissipation, and overflow capacity for the full
tributary area to ensure that flooding and scour is avoided. It is strongly recommended that
BMPs which are designed to less than their target design volume be designed to bypass peak
flows.
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Green Streets Manual
1.3.4 Alternative Compliance Options for Applicable Green Streets Projects
Alternative compliance programs should be considered for applicable Green Streets projects if on-site
green infrastructure approaches cannot practicably treat the design volume. The primary alternative
compliance option for applicable Green Streets projects is the completion of off-site mitigation projects.
The proponent would implement a project to reduce stormwater pollution for other portions of
roadway or similar land uses when being reconstructed to the project in the same hydrologic unit,
ideally as close to the project as possible and discharging to the same outfall.
1.3.5 Infiltration Considerations
Appropriate soils, infiltration media, and infiltration rates should be used for infiltration BMPs. If
infiltration is proposed, a complete geotechnical or soils report should be undertaken to determine
infiltration rates, groundwater depth, soil toxicity and stability, and other factors that will affect the
ability and the desirability of infiltration.
Infiltration infeasibility may result from conditions including the following:
1. The infiltration capacity of the underlying soils is less than 0.3 inch per hour.
2. Locations where seasonal high groundwater is within ten feet of the bottom of the infiltration
facility;
3. Locations susceptible to land subsidence;
4. Locations within 100 feet of a groundwater well used for drinking water;
5. Brownfield development sites or other locations where pollutant mobilization is a documented
concern;
6. Locations with potential geotechnical hazards;
7. Smart growth and infill or redevelopment locations where the density and/ or nature of the
project would create significant difficulty for compliance with the onsite volume retention
requirement.
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Green Streets Manual
EXEMPT PROJECTS
Redevelopment does not include routine maintenance activities that are conducted to maintain original line and grade, hydraulic capacity,
original purpose of facility or emergency redevelopment activity required to protect public health and safety. Impervious surface
replacement, such as the reconstruction of parking lots and roadways which does not disturb additional area and maintains the original
grade and alignment, is considered a routine maintenance activity. Redevelopment does not include the repaving of existing roads to
maintain original line and grade.
GREEN STREETS CATEGORIES
Street and road construction applies to major arterials, state routes, highways, or rail lines used for the movement of people or goods
by means of bus services, trucks, and vehicles, and transportation corridors within larger projects. Projects which are required to follow
the Rancho Palos Verdes Green Streets Guidance Manual include the following:
1. New street and road construction of 10,000 square feet or more of impervious surface area.
2. Street and road redevelopment resulting in the creation or addition or replacement of 5,000 square feet or more of impervious
surface area on an already developed site.
GREEN STREETS BMP SELECTION
Does the project fall into one of the
Green Streets categories above?
Green Streets
Does Not Apply
City of Rancho Palos Verdes
NO
YES
Determine Site
Conditions and
Constraints
Is Infiltration Feasible? YES
NO
Is space Available for I Implement
Biotreatment BMPs Infiltration BMPs
(Section 2)
NO I YES
Implement
Biotreatment BMPs
(Section 3)
Figure 1: BMP Selection Flow Chart.
Page 6
April 2015
44
Implement
Treatment BMPs
(Section 4)
LARAPCHO
PkLOS VHRaS
City of Rancho Palos Verdes
NO
YES
Determine Site
Conditions and
Constraints
Is Infiltration Feasible? YES
NO
Is space Available for I Implement
Biotreatment BMPs Infiltration BMPs
(Section 2)
NO I YES
Implement
Biotreatment BMPs
(Section 3)
Figure 1: BMP Selection Flow Chart.
Page 6
April 2015
44
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Green Streets Manual
Table 3: BMP Location Opportunity Summary.
BMP
Location Opportunity Summary
Bioretention
Adjacent to traveled way and in frontage or furniture sidewalk zones
Can be located in curb extensions, medians, traffic circles, roundabouts, and any other landscaped area
Suitable for constrained locations
Infiltration Trench/Dry Well
Can be located under sidewalks and in sidewalk planting strips, curb extensions, roundabouts, and medians
Rain Gardens
Can be integrated medians, islands, circles, street ends, chicanes, and curb extensions
Can be located at the terminus of swales in the landscape
Permeable Pavement
Suitable for parking or emergency access lanes
Can be located in furniture zones of sidewalks especially adjacent to tree wells
Cannot be placed in areas with large traffic volume or heavy load lanes
Avoid steep streets
Cannot be placed within 20 feet of sub -sidewalk basements
Cannot be within 50 feet of domestic water wells
Flow -Through Planters
Above -grade planters should be structurally separate from adjacent sidewalks
At -grade planter systems can be installed adjacent to curbs within the frontage and/or furniture zones
Vegetated Swales
Can be located adjacent to roadways, sidewalks, or parking areas
Can be integrated into traffic calming devices such as chicanes and curb extensions
Can be placed in medians where the street drains to the median
Can be placed alongside streets and pathways
Should be designed to work in conjunction with the street slope
Vegetated Buffer Strips
Can be located in multi -way boulevards, park edge streets, or sidewalk furniture zones
Can serve as pre-treatment
Treatment BMPs
Can be located in a catch basin, manhole, or vault
Can be installed on an existing outlet pipe or at the bottom of an existing catch basin with an overflow
Can be placed on existing curbside catch basins and flush grate openings
Can be installed on the existing wall of a catch basin and on the curb side wall of a catch basin
Minimum set -backs from foundations and slopes should be observed if the BMP is not lined
Street Trees
Can be placed on sidewalks, in furniture zones, and on medians
Adequate spacing must be provided between trees and street lights, pedestrian lights, accessible parking
spaces, bus shelters, awnings, canopies, balconies, and signs
City of Rancho Palos Verdes Page 8 April 2015
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Green Streets Manual
SECTION 2 - INFILTRATION
Infiltration systems utilize rock, gravel, and other highly permeable materials for on-site infiltration. In
these systems, stormwater runoff is directed to the system and allowed to infiltrate into the soils for on-
site retention and groundwater recharge. During small storm events, infiltration systems can result in
significant or even complete volume reduction of stormwater runoff.
Infiltration should be used to the maximum extent practicable. Biotreatment BMPs should be
considered if infiltration is found to be infeasible due to low infiltration rates, soil instability, high
groundwater, or soil contamination.
Infiltration BMPs may become damaged by stormwater carrying high levels of sediment, therefore pre-
treatment features should be designed to treat street runoff prior to discharging to infiltration features.
Media filters, filter inserts, vortex type units, bioretention devices, sumps, and sedimentation basins are
several pre-treatment tools effective at removing sediment.
2.1 INFILTRATION TRENCHES AND DRY WELLS
Drain Rock
Native
Optional Filter Fabric
Perforated Pipe
Figure 3: Infiltration Trench (Model for Living Streets Design Manual, 2011).
Description
Infiltration trenches are linear, rock -filled features that promote infiltration by providing a high ratio of
sub -surface void space in permeable soils. They provide on-site stormwater retention and may
contribute to groundwater recharge. Infiltration trenches may accept stormwater from sheet flow,
concentrated flow from a Swale or other surface feature, or piped flow from a catch basin. Because they
are not flow-through BMPs, infiltration trenches do not have outlets but may have overflow outlets for
large storm events.
Dry wells are typically distinguished from infiltration trenches by being deeper than they are wide. They
are usually circular, resembling a well, and are backfilled with the same materials as infiltration
trenches. Dry wells typically accept concentrated flow from surface features or from pipes and do not
have outlets.
Infiltration trenches and dry wells are typically designed to infiltrate all flow they receive. In large storm
events, partial infiltration of runoff can be achieved by providing an overflow outlet. In these systems,
significant or even complete volume reduction is possible in smaller storm events. During large storm
events, these systems may function as detention facilities and provide a limited amount of retention and
infiltration.
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Green Streets Manual
Location and placement guidelines
Infiltration trenches and dry wells typically have small surface footprints so they are potentially some of
the most flexible elements of landscape design. However, because they involve sub -surface excavation,
these features may interfere with surrounding structures. Care needs to be taken to ensure that
surrounding building foundations, pavement bases, and utilities are not damaged by infiltration
features. Once structural soundness is ensured, infiltration features may be located under sidewalks and
in sidewalk planting strips, curb extensions, roundabouts, and medians. When located in medians, they
are most effective when the street is graded to drain to the median. Dry wells require less surface area
than trenches and may be more feasible in densely developed areas.
Infiltration features should be sited on uncompacted soils with acceptable infiltration capacity. They are
best used where soil and topography allow for moderate to good infiltration rates (0.3 inches per hour
or better) and the depth to groundwater is at least 10 feet. Prior to design of any retention or infiltration
system, proper soil investigation and percolation testing shall be conducted to determine appropriate
infiltration design rates, depth to groundwater, and if soil will exhibit instability as a result of infiltration.
Any site with potential for previous underground contamination shall be investigated. Infiltration
trenches and dry wells can be designed as stand-alone systems when water quality is not a concern or
may be combined in series with other stormwater tools.
Perforated pipes and piped inlets and outlets may be included in the design of infiltration trenches.
Cleanouts should be installed at both ends of any piping and at regular intervals in long sections of
piping, to allow access to the system. Access ports are recommended for both trenches and wells and
can be combined with clean -outs. If included, the overflow inlet from the infiltration trench should be
properly designed for anticipated flows.
2.2 RAIN GARDENS
Figure 4: Rain garden (Model for Living Streets Design Manual, 2011).
Description
Rain gardens are vegetated depressions in the landscape. They have flat bottoms and gently sloping
sides. Rain gardens can be similar in appearance to swales, but their footprints may be any shape. Rain
gardens hold water on the surface, like a pond, and have overflow outlets. The detained water is
infiltrated through the topsoil and subsurface drain rock unless the volume of water is so large that
City of Rancho Palos Verdes Page 10 April 2015
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Green Streets Manual
some must overflow. Rain gardens can reduce or eliminate off-site stormwater discharge while
increasing on-site recharge.
Location and Placement Guidelines
Rain gardens may be placed where there is sufficient area in the landscape and where soils are suitable
for infiltration. Rain gardens can be integrated with traffic calming measures installed along streets, such
as medians, islands, circles, street ends, chicanes, and curb extensions. Rain gardens are often used at
the terminus of swales in the landscape.
2.3 PERMEABLE PAVEMENT
Figure 5: Permeable pavement during a storm event (Model
for Living Streets Design Manual, 2011).
Description
Permeable pavement is a system with the primary purpose of slowing or eliminating direct runoff by
absorbing rainfall and allowing it to infiltrate into the soil. Permeable pavement also filters and cleans
pollutants such as petroleum deposits on streets, reduces water volumes for existing overtaxed pipe
systems, and decreases the cost of offsite or onsite downstream infrastructure. This BMP is impaired by
sediment -laden run-on which diminishes its porosity. Care should be taken to avoid flows from
landscaped areas reaching permeable pavement. Permeable pavement is, in certain situations, an
alternative to standard pavement. Conventional pavement is designed to move stormwater off-site
quickly. Permeable pavement, alternatively, accepts the water where it falls, minimizing the need for
management facilities downstream.
Location and Placement Guidelines
t
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pavement I
Utility and Infrastructure ,.
Zone
Figure 6: Possible pervious pavement design layout (Model for Living Streets Design Manual, 2011).
City of Rancho Palos Verdes Page 11 April 2015
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Green Streets Manual
Conditions where permeable pavement should be encouraged include:
• Sites where there is limited space in the right-of-way for other BMPs;
• Parking or emergency access lanes; and
• Furniture zones of sidewalks especially adjacent to tree wells
Conditions where permeable pavement should be avoided include:
• Large traffic volume or heavy load lanes;
• Where runoff is already being harvested from an impervious surface for direct use, such as
irrigation of bioretention landscape areas;
• Steep streets;
• Gas stations, car washes, auto repair, and other sites/sources of possible chemical
contamination;
• Areas with shallow groundwater;
• Within 20 feet of sub -sidewalk basements; and
• Within 50 feet of domestic water wells.
Material and Design Guidelines
A soil or geotechnical report should be conducted to provide information about the permeability rate of
the soil, load-bearing capacity of the soil, the depth to groundwater (10 feet or more required), and if
soil will exhibit instability as a result of implementation. Infiltration rate and load capacity are key
factors in the functionality of this BMP. Permeable pavement generally does not have the same load-
bearing capacity as conventional pavement, so this BMP may have limited applications depending on
the underlying soil strength and pavement use. Permeable pavement should not be used in general
traffic lanes due to the possible variety of vehicles weights and heavy volumes of traffic.
When used as a road paving, permeable pavement that carries light traffic loads typically has a thick
drain rock base material. Pavers should be concrete as opposed to brick or other light-duty materials.
Other possible permeable paving materials include porous concrete and porous asphalt. These surfaces
also have specific base materials that detain infiltrated water and provide structure for the road surface.
Base material depths should be specified based on design load and the soils report.
Plazas, emergency roads, and other areas of limited vehicular access can also be paved with permeable
pavement. Paving materials for these areas may include open cell paver blocks filled with stones or grass
and plastic cell systems. Base material specifications may vary depending on the product used, design
load, and underlying soils.
When used for pedestrian paths, sidewalks, and shared -use paths, appropriate materials include those
listed above as well as rubber pavers and decomposed granite or something similar (washed or pore -
clogging fine material). Pedestrian paths may also use broken concrete pavers as long as ADA
requirements are met. Paths should drain into adjoining landscapes and should be higher than adjoining
landscapes to prevent run-on. Pavement used for sidewalks and pedestrian paths should be ADA
compliant, especially smooth, and not exceed a 2 percent slope or have gaps wider than 0.25 inches. In
general, tripping hazards should be avoided.
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Green Streets Manual
Design considerations for permeable pavement include:
• The location, slope and load-bearing capacity of the street, and the infiltration rate of the soil;
• The amount of storage capacity of the base course;
• The traffic volume and load from heavy vehicles;
• The design storm volume calculations and the quality of water; and
• Drain rock, filter fabrics, and other subsurface materials.
Maintenance Guidelines
Maintenance of permeable pavement systems is essential to their continued functionality. Regular
vacuuming and street sweeping should be performed to remove sediment from the pavement surface.
The bedding and base material should be selected for long life and sufficient infiltration rates.
SECTION 3 - BIOTREATMENT
Biotreatment BMPs are landscaped, shallow depressions that capture and filter stormwater runoff.
These types of BMPs are an increasingly common type of stormwater treatment device that are installed
at curb level and filled with a bioretention type soil. They are designed as soil and plant -based filtration
devices that remove pollutants through a variety of physical, biological, and chemical treatment
processes. They typically consist of a ponding area, mulch layer, planting soils, and plants. Stormwater is
directed to the system and pollutants are treated as the stormwater drains through the planting soil and
either infiltrated or collected by an underdrain and directed to a collection system.
Biotreatment should only be used in cases where infiltration has been proven infeasible due to low
infiltration rates, soil instability, high groundwater, or soil contamination.
3.1 BIORETENTION
t
Afi
Figure 7: Bioretention system (Model for Living Streets Design Manual, 2011).
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Green Streets Manual
Description
Bioretention is a stormwater management process that cleans stormwater by mimicking natural soil
filtration processes as water flows through a bioretention BMP. It incorporates mulch, soil pores,
microbes, and vegetation to reduce and remove sediment and pollutants from stormwater. Bioretention
is designed to slow, spread, and, to some extent, infiltrate water. Each component of the bioretention
BMP is designed to assist in retaining water, evapotranspiration, and adsorption of pollutants into the
soil matrix. As runoff passes through the vegetation and soil, the combined effects of filtration,
absorption, adsorption, and biological uptake of plants remove pollutants.
For areas with low permeability or other soil constraints, bioretention can be designed as a flow-through
system with a barrier protecting stormwater from native soils. Bioretention areas can be designed with
an underdrain system that directs the treated runoff to infiltration areas, cisterns, or the storm drain
system, or may treat the water exclusively through surface flow. Examples of bioretention BMPs include
swales, planters, and vegetated buffer strips.
Location and Placement Guidelines
Bioretention facilities can be included in the design of all street components; adjacent to the traveled
way and in the frontage or furniture sidewalk zones. They can be designed into curb extensions,
medians, traffic circles, roundabouts, and any other landscaped area. Depending on the feature,
maintenance and access should always be considered in locating the device. Bioretention systems are
also appropriate in constrained locations where other stormwater facilities requiring more extensive
subsurface materials are not feasible.
If bioretention devices are designed to include infiltration, native soil should have a minimum
permeability rate of 0.3 inches per hour and at least 10 feet to the groundwater table. Sites that have
more than a 5 percent slope may require other stormwater management approaches or special
engineering.
3.2 FLOW-THROUGH PLANTERS
Figure 8: Flow-through planter (Model for Living Streets Design Manual, 2011).
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Green Streets Manual
Description
Flow-through planters are typically above -grade or at -grade with solid walls and a flow-through bottom.
They are contained within an impermeable liner and use an underdrain to direct treated runoff back to
the collection system. Where space permits, buildings can direct roof drains first to building -adjacent
planters. Both underdrains and surface overflow drains are typically installed with building -adjacent
planters.
At -grade street -adjacent planter boxes are systems designed to take street runoff and/or sidewalk
runoff and incorporate bioretention processes to treat stormwater. These systems may or may not
include underdrains.
Location and Placement Guidelines
Above -grade planters should be structurally separate from adjacent sidewalks to allow for future
maintenance and structural stability per local department of public works' standards. At -grade planter
systems can be installed adjacent to curbs within the frontage and/or furniture zones.
All planters should be designed to pond water for less than 48 hours after each storm. Flow-through
planters designed to detain roof runoff can be integrated into a building's foundation walls, and may be
either raised or at grade.
For at -grade planters, small localized depressions may be included in the curb opening to encourage
flow into the planter. Following the inlet, a sump (depression) to capture sediment and debris may be
integrated into the design to reduce sediment loadings.
3.3 VEGETATED SWALES
Figure 9: Vegetated swale (Signal Hill, CA).
Description
Swales are linear, vegetated depressions that capture rainfall and runoff from adjacent surfaces. The
swale bottom should have a gradual slope to convey water along its length. Swales can reduce off-site
stormwater discharge and remove pollutants along the way. In a swale, water is slowed by traveling
through vegetation on a relatively flat grade. This gives particulates time to settle out of the water while
contaminants are removed by the vegetation.
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Green Streets Manual
Location and Placement Guidelines
Swales can easily be located adjacent to roadways, sidewalks, or parking areas. Roadway runoff can be
directed into swales via flush curbs or small evenly -spaced curb cuts into a raised curb. Swale systems
can be integrated into traffic calming devices such as curb extensions.
Swales can be placed in medians where the street drains to the median. Placed alongside streets and
pathways, vegetated swales can be landscaped with native plants which filter sediment and pollutants
and provide habitat for wildlife. Swales should be designed to work in conjunction with the street slope
to maximize filtration and slowing of stormwater.
Swales are designed to allow water to slowly flow through the system. Depending on the landscape and
design storm, an overflow or bypass for larger storm events may be needed. Curb openings should be
designed to direct flow into the swale. Following the inlet, a sump may be built to capture sediment and
debris.
3.4 VEGETATED BUFFER STRIPS
~' Nadve or Designed
Growing Medium
Figure 10: Vegetated buffer strip detail (Model for Living Streets Design Manual, 2011).
Description
Vegetated buffer strips are sloping planted areas designed to treat and absorb sheet flow from adjacent
impervious surfaces. These strips are not intended to detain or retain water, only to treat it as a flow-
through feature. They should not receive concentrated flow from swales or other surface features, or
concentrated flow from pipes.
Location and Placement Guidelines
Vegetated buffer strips are well-suited to treating runoff from roads and highways, small parking lots,
and pervious surfaces. They may be commonly used on multi -way boulevards, park edge streets, or
sidewalk furniture zones with sufficient space. When selecting potential placement the need for
supplemental irrigation should be considered. Vegetated buffers can also be situated so they serve as
pre-treatment for another stormwater management feature, such as an infiltration BMP.
City of Rancho Palos Verdes Page 16 April 2015
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Green Streets Manual
SECTION 4 - TREATMENT BMPS
4.1 SAND FILTERS & STORM DRAIN INLET PROTECTIONS
As described in Section 1 of this Green Streets Manual, it may be infeasible for specific projects to apply
infiltration or biotreatment BMPs. In these cases, sand filters or filter inserts as treatment BMPs can be
considered as an alternative. Sand filters and filter inserts can be designed to prevent particulates,
debris, metals, and petroleum-based materials conveyed by stormwater from entering the storm drain
system. All treatment BMP units should have an overflow system that allows the storm drain to remain
functional if the filtration system becomes clogged during rainstorms. All storm drain inlet protections
must be of a style and configuration approved by the agency with ownership of the inlet.
Typical maintenance of catch basins includes scheduled trash removal if a screen or other debris
capturing device is used. Street sweeping should be performed by vacuum sweepers with occasional
weed and large debris removal. Maintenance should include keeping a log of the amount of sediment
collected and the data of removal.
The following are examples of acceptable treatment BMPs:
Sand Filters: Sand filters are designed to filter stormwater through a constructed media bed and
to an underdrain system. As stormwater flows through the media pollutants are filtered out of
the water. The filtered water is conveyed through the underdrain to a collection system.
Pretreatment is necessary to eliminate significant sediment load or other large particles which
would clog the system. Minimum set -backs from foundations and slopes should be observed if
the facility is not lined. Filters should be designed and maintained such that ponded water
should not persist for longer than 48 hours following a storm event.
Cartridge Media Filters: Cartridge media filters contain multiple modular filters which contain
engineered media. The filters can be located in a catch basin, manhole, or vault. The manhole or
vault may be divided into multiple chambers so that the first chamber may act as a pre -settling
basin for removal of coarse sediment while the next chamber may act as the filter chamber.
Cartridge media filters are recommended for drainage areas with limited available surface area
or where surface BMPs would restrict uses. Depending on the number of cartridges,
maintenance events can have long durations. Locations should be chosen so that maintenance
events will not significantly disrupt businesses or traffic. Inlet inserts should be sized to capture
all debris and should therefore be selected to match the specific size and shape of each catch
basin and inlet. Filter media should be selected to target pollutants of concern. A combination of
media may be used to remove a variety of pollutants. Systems with lower maintenance
requirements are preferred.
Storm Drain Inlet Screens: Inlet screens are designed to prevent large litter and trash from
entering the storm drain system while allowing smaller particles to pass through. The screens
function as the first preventive measure in removing pollutants from the storm water system.
The city's street sweeping department should be consulted to ensure compliance with local
specifications and to schedule regular maintenance. Annual inspection of the screen is
recommended to ensure functionality. Note that most LA River drainage areas are already
protected using connector pipe screens through collective systems.
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Green Streets Manual
Storm Drain Pipe Filter Insert: The storm drain outlet pipe filter is designed to be installed on an
existing outlet pipe or at the bottom of an existing catch basin with an overflow. This filter
removes debris, particulates, and other pollutants from stormwater as it leaves the storm drain
system. This BMP is less desirable than a protection system that prevents debris from entering
the storm drain system because the system may become clogged with debris. Outlet pipe filters
can be placed on existing curbside catch basins and flush grate openings. Regular maintenance is
required and inspection should be performed rigorously. Because this filter is located at the
outlet of a storm drain system, clogging with debris is not as apparent as with filters at street
level. This BMP may be used as a supplemental filter with an inlet screen or inlet insert unit.
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Green Streets Manual
SECTION 5 - STREET TREES
5.1 STREET TREES
Figure 11: Street trees (Signal Hill, CA).
Description
Healthy urban trees are powerful stormwater management tools. Leaves and branches catch and slow
rain as it falls, helping it to soak into the ground. The plants themselves take up and store large
quantities of water that would otherwise contribute to surface runoff. Part of this moisture is then
returned to the air through evaporation to further cool the city. As an important element along
sidewalks, street trees must be provided with conditions that allow them to thrive, including adequate
uncompacted soil, water, and air.
The goal of adding street trees is to increase the canopy cover of the street, the percentage of its
surface either covered by or shaded by vegetation. The selection, placement, and management of all
elements in the street should enhance the longevity of a city's street trees and healthy, mature
plantings should be retained and protected whenever possible.
Benefits to adding street trees include:
• Creation of shade to lower temperatures in a city, reduces energy use, and makes the street a
more pleasant place in which to walk and spend time
• Slowing and capture of rainwater, helping it soak into the ground to restore local hydrologic
functions and aquifers
• Improving air quality by cooling air, producing oxygen, and absorbing and storing carbon in
woody plant tissues
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Green Streets Manual
SECTION 6 - DEFINITIONS
Best Management Practice (BMP) — Operating methods and/or structural devices used to reduce
stormwater volume, peak flows, and/or pollutant concentrations of stormwater runoff through
evapotranspiration, infiltration, detention, filtration, and/or biological and chemical treatment.
Bioretention — Soil and plant -based retention practice that captures and biologically degrades pollutants
as water infiltrates through sub -surface layers containing microbes that treat pollutants. Treated runoff
is then slowly infiltrated and recharges the groundwater.
Conveyance — The process of water moving from one place to another.
Design Storm — A storm whose magnitude, rate, and intensity do not exceed the design load for a storm
drainage system or flood protection project.
Detention — Stormwater runoff that is collected at one rate and then released at a controlled rate. The
volume difference is held in temporary storage.
Filtration — A treatment process that allows for removal of solid (particulate) matter from water by
means of porous media such as sand, soil, vegetation, or a man-made filter. Filtration is used to remove
contaminants.
Furniture Zone —The furniture zone is the area which lies between the curb and pedestrian zones and is
intended to house utilities and pedestrian amenities.
Hardscape — Impermeable surfaces, such as concrete or stone, used in the landscape environment along
sidewalks or in other areas used as public space.
Infiltration —The process by which water penetrates into soil from the ground surface.
Permeability/Impermeability —The quality of a soil or material that enables water to move through it,
determining its suitability for infiltration.
Retention —The reduction in total runoff that results when stormwater is diverted and allowed to
infiltrate into the ground through existing or engineered soil systems.
Runoff — Water from rainfall that flows over the land surface that is not absorbed into the ground.
Sedimentation —The deposition and/or settling of particles suspended in water as a result of the
slowing of the water.
Stormwater— Water runoff from rain or snow resulting from a storm.
Transportation Corridor —A major arterial, state route, highway, or rail line used for the movement of
people or goods by means of bus services, trucks, and vehicles.
SECTION 7 - REFERENCES
1. Los Angeles County. Model for Living Streets Design Manual. 2011.
2. U.S. Environmental Protection Agency (EPA). Managing Wet Weather With Green Infrastructure
Municipal Handbook: Green Streets. December 2008.
3. Orange County. Technical Guidance Document. May 2011.
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