HomeMy Public PortalAbout16) 9.A. Intro and First Reading of Low Impact Development Standards and a Green Streets PolicyDATE:
TO:
FROM:
SUBJECT:
AGENDA
ITEM 9.A.
COMMUNITY DEVELOPMENT DEPARTMENT
MEMORANDUM
November 5 , 2013
The Honorable City Council
Jose E. Pulido, City Manager h.,
Via: Mark Persico, AICP, Com~ unity Development Director
By: Hesty Liu, AICP , Associate Planner
INTRODUCTION AND FIRST READING OF ORDINANCE NO. 13-979,
AMENDING ARTICLE E ("SITE PLAN REVIEW AND CONGESTION
MANAGEMENT") OF CHAPTER 1 ("ZONING CODE") OF TITLE 9
("ZONING REGULATIONS") OF THE TEMPLE CITY MUNICIPAL CODE
TO ESTABLISH LOW IMPACT DEVELOPMENT (LID) STANDARDS AND
A GREEN STREETS POLICY
RECOMMENDATION:
The City Council is requested to:
a) Introduce Ordinance No. 13-979 (Attachment "A") for first reading by title only,
amending Article E ("Site Plan Review and Congestion Management") of Chapter 1
("Zoning Code") of Title 9 ("Zoning Regulations") of the Temple City Municipal Code
to establish Low Impact Development (LID) standards and a Green Streets Policy;
b) Waive further reading of Ordinance No. 13-979; and
c) Schedule the second reading of Ordinance No . 13-979 for November 19, 2013.
BACKGROUND:
1. On November 8, 2012 , under the authority of the Clean Water Act, the Los
Angeles Regional Water Quality Control Board adopted the Municipal Separate
Storm Sewer System Permit (known as MS4 Permit), which requires that all local
jurisdictions in Los Angeles County (i.e., Permittees) electing to participate in a
Watershed Management Program or an Enhanced Watershed Management
Program have LID ordinances in place. MS4 Permit also requ i res Permittees to
City Council
November 5, 2013
Page 2 of 4
have a Green Streets Policy in place and/or commence development of a policy
that specifies the use of green street strategies for transportation corridors. The
deadline for compliance is December 15, 2013.
2. On June 28, 2013, Temple City submitted a Notice of Intent to the Los Angeles
Regional Water Quality Control Board, indicating the intention of participating in
the Enhanced Watershed Management Program (EWMP) of the Upper Los Angeles
River Watershed Group.
3. From July to September 2013, staff worked on developing LID standards and a
Green Streets Policy for the City, in order to comply with the deadline of MS4
Permit issued by the California Regional Water Quality Control Board, Los Angeles
Region.
4. On October 17, 2013, the Planning Commission reviewed the Draft Ordinance No.
13-979, the proposed Temple City LID Manual, and the proposed Temple City
Green Streets Manual. The Planning Commission made the recommendation to
the City Council to adopt the proposed code amendment, the proposed LID
Manual, and Green Streets Manual (See "Attachment D" for Planning Commission
staff report).
ANALYSIS:
As a participant of the Enhanced Watershed Management Program of the Upper Los
Angeles River Watershed Group, Temple City must adopt a LID ordinance and a streets
policy to comply with the MS4 Permit requirement before the deadline. Noncompliance
will subject the City to a fine of potentially up to $10,000 per day.
The goals of requiring the implementation of Low Impact Development Standards and
Green Streets policy are to provide source control of stormwater as well as to reduce the
amounts of pollutants in stormwater and urban runoff. In light of the MS4 Permit mandate
and the goals of the regional water board, staff proposes four categories for the
implementation of LID in Temple City:
Category 1.
Category 2.
Category 3.
Exemption: The project will disturb less than 500 square feet of soil.
Residential LID Category: The project is a residential development,
involves 4 or less dwelling units and will disturb more than 500 square
feet of soil.
Commercial/Industrial LID Category: The project is a residential
development involving 5 or more dwelling units, or is at a commercial or
City Council
November 5, 2013
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Category4.
industrial site. The project will also disturb more than 500 square feet of
soil.
Projects covered by MS4 Permit applicability list: The project is subject
to the provision of the Municipal Separate Storm Sewer System permit
(MS4) issued by the California Regional Water Quality Control Board.
Under the MS4 permit, implementing LID Standards for projects not covered by MS4
applicability list but will "result in the creation or addition or replacement of 500 square
feet or more of impervious surface area" is not mandatory. However, considering that
the majority of the projects in Temple City are smaller projects, and implementing LID
would benefit the community, staff proposes creating two additional categories (
Category 2 and 3), for inclusion in the LID implementation. Requirements developed for
Category 2 and 3 are based on the goals of not creating an unnecessary burden on the
property owners and limiting the need for the City's enforcement. Most projects under
the two categories do not need to prepare a separate LID plan, and reviews can be
conducted by City staff. Also, many treatment systems recommended in the LID Manual
are low-maintenance systems, some of which can be easily integrated into the
landscape design of the projects.
The proposed code amendment did not separate applicable criteria for LID and the
Green Streets Policy because they are both covered under the MS4 Permit Applicability
List. Temple City Green Streets Manual is created to provide a technical guidance for
the City's implementation of the Green Streets Policy.
The proposed code amendment is exempt from CEQA, per Section 15061 (b)(3) and
Section 15308 of the CEQA Guidelines. Adopting the proposed code amendment will
enable the City to comply with MS4 Permit mandates and deadline. It is also a
necessary move for the City to participate in the regional effort of water quality control.
By requiring projects to address post-construction stormwater runoff issues, the City will
eventually benefit from a reduction in impermeable surfaces, improved water quality in
the local aquifers, and enhanced landscape and streetscape within the City.
CONCLUSION:
The City Council is requested to adopt the proposed code amendment, the Temple City
LID Manual, and the Temple City Green Streets Manual. The proposed code
amendment is tailored to the development types of the City, with the LID Manual and
Green Streets Manual serving as a technical guide for implementation.
City Council
November 5, 2013
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FISCAL IMPACT:
It is anticipated that the adoption of proposed Ordinance No. 13-979 will not have a
fiscal impact on the Fiscal Year (FY) 2013-14 City Budget. The City will generate
revenue to cover the cost of processing development applications. Staff cannot estimate
at this time how many applications will be approved, however, if the increase in
revenues is significant, staff will return at FY 2013-14 Mid-Year Budget Review with a
revised revenue estimate.
ATTACHMENTS:
A. Ordinance No. 13-979
B. Temple City LID Development Manual
C. Temple City Green Streets Manual
D. Planning Commission Staff Report and Resolution No. 13-2382 PC
CITY OF TEMPLE CITY
ORDINANCE NO. 13-979
Attachment A
AN ORDINANCE OF THE CITY COUNCIL OF THE CITY OF TEMPLE CITY
AMENDING ARTICLE E (SITE PLAN REVIEW AND CONGESTION MANAGEMENT)
OF CHAPTER 1 (ZONING CODE) OF TITLE 9 (ZONING REGULATIONS) OF THE
TEMPLE CITY MUNICIPAL CODE TO ESTABLISH LOW IMPACT DEVELOPMENT
STANDARDS AND A GREEN STREETS POLICY
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 and Green Streets Policies 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, it is the intent of the City to expand the applicability of the existing LID and
Green Streets requirements by providing stormwater and rainwater LID strategies and Green Streets
Policy for Development and Redevelopment projects as defined under "Applicability."
THE CITY COUNCIL OF THE CITY OF TEMPLE CITY HEREBY ORDAINS AS FOLLOWS:
SECTION 1. Based upon information presented in the Planning Commission Staff Report
dated October 17, 2013; and based upon public input which was received at the noticed public hearing
before the Planning Commission on October 17, 2013 to consider amending Article E (Site Plan Review
and Congestion Management) of Chapter 1 (Zoning Code) of Title 9 (Zoning Regulations) of the Temple
City Municipal Code to establish Low Impact Development standards and Green Streets Policies;
SECTION 2. This project is not anticipated to result in any significant effects upon the
environment and is exempt from environmental review in accordance with Sections 15061(b)(3) and
15308 of the CEQA Guidelines. The Preliminary Assessment indicates that there is no potential for
adverse impact to the environment as it relates to all wild animals, birds, plants, fish, amphibians and
Ordinance 13-979
Low Impact Development and Green Streets Policy
Page 2 of 11
related ecological communities, including the habitat upon which the wildlife depends for its continued
viability.
SECTION 3. The Municipal Code shall be amended by adding Part 3 under Article E of Chapter 1
of Title 9, which shall read as follows:
Part 3. Low Impact Development {LID} Standards and Green Streets Policy
9194: DEFINITIONS:
(If the definition of any term contained in this chapter conflicts with the definition of the same term in Order
No. R4-2012-0175, then the definition contained in Order No. R4-2012-0175 shall govern)
AUTOMOTIVE
SERVICE FACILITY
BASIN PLAN
BEST MANAGEMENT
PRACTICE (BMP)
BIOFILTRATION
BIORETENTION
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, 5511, 5541, 7532-7534, and
7536-7539 provided that these facilities have no outside activities or
materials that may be exposed to stormwater (Order No. R4-2012-0175).
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 (Order No. R4-2012-0175).
means practices or physical devices or systems designed to prevent or
reduce pollutant loading from stormwater or non-stormwater discharges
to receiving waters, or designed to reduce the volume of stormwater or
non-stormwater discharged to the receiving water (Order No. R4-2012-
0175).
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 (Order No. R4-2012-0175).
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 Order No.
R4-2012-0175 as biofiltration (Order No. R4-2012-0175).
Ordinance 13-979
Low Impact Development and Green Streets Policy
Page 3 of 11
BIOSWALE means a LID BMP consisting of a shallow channel lined with grass or
other dense, low-growing vegetation. Bioswales are designed to collect
stormwater runoff and to achieve a uniform sheet flow through the dense
vegetation for a period of several minutes (Order No. R4-2012-0175).
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 an NPDES
permit
COMMERCIAL
DEVELOPMENT
COMMERCIAL MALLS
CONSTRUCTION ACTIVITY
CONTROL
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 (Order No. R4-2012-
0175).
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 (Order No. R4-2012-0175).
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 (Order No. R4-2012-
0175).
means to minimize, reduce or eliminate by technological, legal,
contractual, or other means, the discharge of pollutants from an activity
or activities (Order No. R4-2012-0175).
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 (Order No. R4-2012-
0175).
Ordinance 13-979
Low Impact Development and Green Streets Policy
Page 4 of 11
DIRECTLY ADJACENT
DISCHARGE
DISTURBED AREA
FLOW-THROUGH
TREATMENT BMPS
FULL CAPTURE SYSTEM
GENERAL CONSTRUCTION
ACTIVITIES STORM WATER
PERMIT (GCASP)
GENERAL INDUSTRIAL
ACTIVITIES STORM WATER
PERMIT (GIASP)
GREEN ROOF
HILLSIDE
INDUSTRIAL!
COMMERCIAL FACILITY
means situated within 200 feet of the contiguous zone required for the
continued maintenance, function, and structural stability of the
environmentally sensitive area (Order No. R4-2012-0175).
means any release, spill, leak, pump, flow, escape, dumping, or disposal
of any liquid, semi-solid, or solid substance.
means an area that is altered as a result of clearing, grading, and/or
excavation (Order No. R4-2012-0175).
means a modular, vault type "high flow biotreatment" devices contained
within an impervious vault with an underdrain or designed with an
impervious liner and an underdrain (Order No. R4-2012-0175).
means any single device or series of devices, certified by the Executive
Officer, that traps all particles retained by a 5 mm mesh screen and has
a design treatment capacity of not less than the peak flow rate Q
resulting from a one-year, one-hour storm in the sub-drainage area
(Order No. R4-2012-0175).
means the general NPDES permit adopted by the State Board which
authorizes the discharge of stormwater from construction activities under
certain conditions (Order No. R4-2012-0175).
means the general NPDES permit adopted by the State Board which
authorizes the discharge of stormwater from certain industrial activities
under certain conditions (Order No. R4-2012-0175).
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 (Order No. R4-2012-0175).
means a property located in an area with known erosive soil conditions,
where the development contemplates grading on any natural slope that
is 25% or greater and where grading contemplates cut or fill slopes
(Order No. R4-2012-0175).
means any facility involved and/or used in the production, manufacture,
storage, transportation, distribution, exchange or sale of goods and/or
commodities, and any facility involved and/or used in providing
professional and non-professional services. This category of facilities
includes, but is not limited to, any facility defined by either the Standard
Industrial Classifications (SIC) or the North American Industry
Classification System (NAICS). Facility ownership (federal, state,
municipal, private) and profit motive of the facility are not factors in this
definition (Order No. R4-2012-0175).
Ordinance 13-979
Low Impact Development and Green Streets Policy
Page 5 of 11
INDUSTRIAL PARK
INFILTRATION BMP
LOW IMPACT DEVELOPMENT
(LID)
MUNICIPAL SEPARATE
STORM SEWER SYSTEM
(MS4)"
(i)
(ii)
(iii)
(iv)
NATIONAL POLLUTANT
DISCHARGE ELIMINATION
SYSTEM(NPDES)"
NATURAL DRAINAGE
SYSTEM
NEW DEVELOPMENT
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 (Order No. R4-2012-0175).
means a LID BMP that reduces stormwater runoff by capturing and
infiltrating the runoff into in-situ soils or amended onsite soils. Examples
of infiltration BMPs include infiltration basins, dry wells, and pervious
pavement (Order No. R4-2012-0175).
consists of building and landscape features designed to retain or filter
stormwater runoff (Order No. R4-2012-0175).
means a conveyance or system of conveyances (including roads with
drainage systems, municipal streets, catch basins, curbs, gutters,
ditches, manmade channels, or storm drains):
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;
Designed or used for collecting or conveying stormwater;
Which is not a combined sewer; and
Which is not part of a Publicly Owned Treatment Works (POTW) as
defined at 40 CFR Section 122.2.
(40 CFR Section 122.26(b)(8)) (Order No. R4-2012-0175)
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" (Order No. R4-
2012-0175).
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
(Order No. R4-2012-0175).
means land disturbing activities; structural development, including
construction or installation of a building or structure, creation of
impervious surfaces; and land subdivision (Order No. R4-2012-0175).
Ordinance 13-979
Low Impact Development and Green Streets Policy
Page 6 of 11
NON-STORMWATER
DISCHARGE
OUTFALL
PARKING LOT
POLLUTANT
PROJECT
RAINFALL
HARVEST AND USE
RECEIVING WATER
REDEVELOPMENT
REGIONAL BOARD
RESTAURANT
means any discharge to a municipal storm drain system that is not
composed entirely of stormwater (Order No. R4-2012-0175).
means a point source as defined by 40 CFR 122.2 at the point where a
municipal separate storm sewer discharges to waters of the United
States and does not include open conveyances connecting two
municipal separate storm sewers, or pipes, tunnels or other conveyances
with connect segments of the same stream or other waters of the United
Sates and are used to convey waters of the United States. (40 CFR
Section 122.26(b)(9)) (Order No. R4-2012-0175).
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 5,000 square feet or more of surface area, or with 25 or more parking
spaces (Order No. R4-2012-0175).
means any "pollutant" defined in Section 502(6) of the Federal Clean
Water Act or incorporated into the California Water Code Section 13373
(Order No. R4-2012-0175).
means all development, redevelopment, and land disturbing activities.
The term is not limited to "Project" as defined under CEQA (Pub.
Resources Code Section 21 065) (Order No. R4-2012-0175).
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 (Order No.
R4-2012-0175).
means "water of the United States" into which waste and/or pollutants
are or may be discharged (Order No. R4-2012-0175).
means land-disturbing activity that results in the creation, addition, or
replacement of 5,000 square feet or more of impervious surface area on
an already developed site. Redevelopment includes, but is not limited to:
the expansion of a building footprint; add.ltion or replacement of a
structure; replacement of impervious surface area that is not part of
routine maintenance activity; and land disturbing activity related to
structural or impervious surfaces. 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 (Order
No. R4-2012-0175).
means the California Regional Water Quality Control Board, Los Angeles
Region.
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)
(Order No. R4-2012-0175).
Ordinance 13-979
Low Impact Development and Green Streets Policy
Page 7 of 11
RETAIL GASOLINE OUTLET means any facility engaged in selling gasoline and lubricating oils (Order
No. R4-2012-0175).
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. Includes road shoulder work, regrading dirt or gravel roadways and
shoulders and performing 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 (Order No. R4-2012-0175).
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 (Order No. R4-2012-0175).
Ordinance 13-979
Low Impact Development and Green Streets Policy
Page 8 of 11
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 (Order No. R4-2012-0175).
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.
STORM WATER
OR STORMWATER
URBAN RUNOFF
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)).
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.
9195: LOW IMPACT DEVELOPMENT AND GREEN STREETS POLICY
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 "Order
No. R4-2012-0175," 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, grant waivers
from the LID requirements, and collect funds for projects that are granted waivers. Except as
otherwise provided herein, the City shall administer, implement and enforce the provisions of this
Section.
C. Applicability. Development projects subject to Permittee conditioning and approval for the design
and implementation of post-construction controls to mitigate storm water pollution, prior to
completion of the project(s), are:
(1) All development projects equal to 1 acre or greater of disturbed area that adds more than
10,000 square feet of impervious surface area.
(2) Industrial parks 10,000 square feet or more of surface area.
(3) Commercial malls 10,000 square feet or more of surface area.
(4) Retail gasoline outlets with 5,000 square feet or more of surface area.
(5) Restaurants (Standard Industrial Classification (SIC) of 5812) with 5,000 square feet or more
of surface area.
(6) Parking lots with 5,000 square feet or more of impervious surface area, or with 25 or more
parking spaces.
(7) Streets and roads construction of 10,000 square feet or more of impervious surface area.
Street and road construction applies to standalone streets, roads, highways, and freeway
projects, and also applies to streets within larger projects.
(8) 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.
Ordinance 13-979
Low Impact Development and Green Streets Policy
Page 9 of 11
(9) Projects located in or directly adjacent to, or discharging directly to an Environmentally
Sensitive Area (ESA), where the development will:
a. Discharge stormwater runoff that is likely to impact a sensitive biological species or
habitat; and
b. Create 2,500 square feet or more of impervious surface area
(10) Single-family hillside homes.
(11) 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 on Planning
Priority Project categories.
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 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. The Site for every Planning Priority Project shall 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 rainfall harvest and use.
(1) A new single-family hillside home development 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 shall follow
USEPA guidance regarding Managing Wet Weather with Green Infrastructure: Green Streets
(December 2008 EPA-833-F-08-009) to the maximum extent practicable.
(3) The remainder of Planning Priority Projects shall prepare a LID Plan to comply with the
following:
Ordinance 13-979
Low Impact Development and Green Streets Policy
Page 10 of 11
a. Retain stormwater runoff onsite for the Stormwater Quality Design Volume (SWQDv)
defined as the runoff from:
i. The 85th percentile 24-hour runoff event as determined from the Los Angeles County
85th percentile precipitation isohyetal map; or
ii. The volume of runoff produced from a 0.75 inch, 24-hour rain event, whichever is
greater.
b. Minimize hydromodification impacts to natural drainage systems as defined in Order No.
R4-2012-0175.
c. 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:
i. 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 ensile.
ii. Locations where seasonal high groundwater is within five to ten feet of surface grade;
iii. Locations within 100 feet of a groundwater well used for drinking water;
iv. Brownfield development sites or other locations where pollutant mobilization is a
documented concern;
v. Locations with potential geotechnical hazards;
vi. 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.
d. If partial or complete ensile retention is technically infeasible, the project Site may
biofiltrate 1.5 times the portion of the remaining SWQDv that is not reliably retained ensile.
Biofiltration BMPs must adhere to the design specifications provided in Order No. R4-
2012-0175.
i. Additional alternative compliance options such as offsite infiltration and groundwater
replenishment projects may be available to the project Site. The project Site should
contact the City of Temple City to determine eligibility.
e. The remaining SWQDv that cannot be retained or biofiltered onsite must be treated onsite
to reduce pollutant loading. BMPs must be selected and designed to meet pollutant-
specific benchmarks as required per Order No. R4-2012-0175. Flow-through BMPs may
be used to treat the remaining SWQDv and must be sized based on a rainfall intensity of:
i. 0.2 inches per hour, or
ii. The one year, one-hour rainfall intensity as determined from the most recent Los
Angeles County isohyetal map, whichever is greater.
E. Additional Requirements. The site for projects not classified with general applicability listed in
Section C of this Ordinance, but resulting in the creation or addition or replacement of 500 square
feet or more of impervious surface area shall be designed to control pollutants, pollutant loads,
and runoff volume per the Temple City Low Impact Development Manual.
Ordinance 13-979
Low Impact Development and Green Streets Policy
Page 11 of 11
9196: VALIDITY:
If any provision of this Ordinance is found to be unconstitutional or otherwise invalid by any court of
competent jurisdiction, such invalidity shall not affect remaining provisions of this Ordinance are declared
to be severable.
SECTION 4. This Ordinance shall be effective on the 31st day after adoption.
SECTION 5. The City Clerk shall certify to the passage and adoption of this ordinance and to its approval
by the Mayor and shall cause the same to be published according to law.
APPROVED AND ADOPTED THIS 19TH DAY OF NOVEMBER 2013.
MAYOR
ATIEST: APPROVED AS TO FORM:
CITY CLERK CITY ATIORNEY
I, City Clerk of the City of Temple City, hereby certify that the foregoing Ordinance 13-979 was
introduced at the regular meeting of the City Council of the City of Temple City held on the 51h day of
November, 2013 and was duly passed, approved and adopted by said Council, a~proved and signed by
the Mayor and attested to by the City Clerk at the regular meeting held on the 191 day of November, 2013
by the following vote:
AYES:
NOES:
ABSENT:
ATTEST:
CITY CLERK
Councilmember-
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LID Technical Guidance Manual
TABLE OF CONTENTS
Section 1-lntroduction ............................................................................................................................... 3
1.1 What Is LID? .................................................................................................................................. 3
1.2 Why Is LID being required? ........................................................................................................... 3
1.3 Project Applicability ...................................................................................................................... 4
1.4 LID Exemptions ............................................................................................................................. 6
Section 2-Commonly Asked Questions ...................................................................................................... 7
Section 3-Design Guidelines and Specifications ........................................................................................ 8
3.1 Design Capture Volume ................................................................................................................ 8
3.2 Flow-Through Planter Box ............................................................................................................ 9
3.3 Vegetated Swale ......................................................................................................................... 11
3.4 Rain Garden ................................................................................................................................ 13
3.5 "Hollywood" Driveway ............................................................................................................... 15
3.6 Bottomless Trench ...................................................................................................................... 17
Section 4-References ............................................................................................................................... 19
City of Temple City 2013
LID Technical Guidance Manual
SECTION 1 -INTRODUCTION
1.1 WHATIS LID?
LID Stands for: Low Impact Development, it is a stormwater management strategy that emphasizes
conservation and the use of existing natural site features integrated with distributed, small-scale
stormwater controls to more closely mimic natural hydrologic patterns in residential, commercial, and
industrial settings.
1.2 WHY IS LID BEING REQUIRED?
The urbanization of Southern California has disrupted the natural flow of stormwater runoff. Rain falling
on roofs now flows into metal or plastic downspouts, then to concrete curbs and gutters along asphalt
roads, then to concrete storm drains, then to concrete river channels, and then finally into estuaries and
the Pacific Ocean.
You can see the problem; rainwater no longer comes into contact with dirt and vegetation. Any
pollutants (heavy metals, bacteria, nutrients, pesticides) that would have previously been naturally
degraded, are now flowing straight out to environmentally sensitive areas.
LID is a new design strategy that corrects this problem. There are many highly technical manuals for
designing LID systems, some of which are listed in Section 4 herein. The purpose of this guidance manual
is to simplify your design.
Typical LID systems include:
• Flow-Through Planter Boxes
• Vegetative Swales
• Rain Gardens
• "Hollywood" Driveways
• Bottomless Trenches
In addition to the LID systems listed above, there are many other acceptable systems such as capture
and re-use (cisterns/ rain barrels), green roofs, pervious pavement/pavers, turf block, etc. However, the
design, installation, and subsequent operation and maintenance of these systems can be complex and
should be carefully evaluated prior to being proposed. When using these other systems, a published
design standard shall be followed.
City of [Temple City] Page 3 of19 2013
LID Small Site Technical Guidance Manual
1.3 PROJECT APPLICABILITY
Step 1: Categories.
There are four LID categories. The first step in LID design is to determine which category the project fits
into.
Category 1.
Category 2.
Category 3.
Category4.
The project will disturb less than 500 square feet of soil
The project is exempt from LID requirements.
The project is residential, will involve 4 or less dwelling units and will disturb more than
500 square feet of soil
The project falls under the Residential LID Categorv.
The project will involve 5 or more dwelling units or is at a commercial or industrial site.
It will disturb more than 500 square feet of soil
The project falls under the Commerciol/fndustrial LID Category.
The project is subject to the provision of the Municipal Separate Storm Sewer System
permit (MS4) issued by the California Regional Water Quality Control Board. These
projects typically include (but are not limited to): new industrial parks 10,000 square
feet or more; new commercial malls 10,000 square feet or more; Retail gasoline outlets
5,000 square feet or more; new restaurants 5,000 square feet or more; new parking lots
5,000 square feet or more; or the creation or addition or replacement of 5,000 square
feet or more of impervious surfaces of existing projects meeting the Regional Board's
applicability criteria.
The project is beyond the scope of this manual and is subject to the requirements as
outlined in the MS4 Permit.
Step 2: LID Design Requirements.
For Residential LID Projects (Category 2)
• A Residential LID Project must incorporate two or more of the following LID systems in the project
design (The systems must be shown on the plans submitted to the City):
1. Porous pavement:
Install porous pavement that allows rainwater to infiltrate through it. Porous
pavement includes, but is not limited to, porous asphalt, porous concrete, ungrouted
paving blocks, and gravel. At least 50 percent of the pavement on the lot shall be
porous. For an example of a driveway that allows rainwater infiltration, see section 3.5,
"Hollywood driveway."
2. Downspout routing
Each roof downspout shall be directed to one of the following BMPs. The sum of the
capacity of the downspout BMPs shall total at least 200 gallons.
City of Temple City 2013
LID Small Site Technical Guidance Manual
a. Cistern/rain barrel
Direct roof downspouts to rain barrels or cisterns. The stored
storm water can then be used for irrigation or other nonpotable uses as
permitted under the Los Angeles County Building/Plumbing Code.
b. Rain garden/planter box
Direct roof downspouts to rain gardens or planter boxes that provide
retention and treatment of stormwater (see Section 3.4 for details).
3. Disconnect impervious surfaces
Slope driveways and other impervious surfaces to drain toward pervious surfaces. If
possible, runoff should be directed toward vegetated areas or water quality BMPs.
The ratio of impervious to pervious area shall be no less than 2:1. Limit the total
area not directed toward vegetated areas or water quality BMPs to 10 percent or
less of the impervious surfaces.
4. Dry well
Install a dry well to infiltrate stormwater. The dry well shall be sized to contain and
infiltrate at least 200 gallons of stormwater in a 36 hour period.
5. Bottomless trench
Install a bottomless trench across the end driveway to catch rainfall as it washes down
the driveway towards the street (see Section 3.6 for details).
5. Landscaping and landscape irrigation
Plant trees near impervious surfaces to intercept rainfall in their leaves. Trees
planted adjacent to impervious surfaces can intercept water that otherwise would
have become runoff. A minimum of two 15 gallon trees shall be planted a maximum
of 10 feet from impervious surfaces. Install irrigation systems that minimize water
usage and eliminate dry-weather urban runoff.
• Before a project can be approved, the following must be verified through the plan check process:
o The following statement must be included on the plans:
As the engineer/architect of record for this project, I have designed the LID system in
accordance with the design criteria of the City of Temple City's LID Guidance Manual.
o The project engineer/architect must make sure the safety and soil stability of the LID system
is carefully evaluated prior to its inclusion in the design.
o Language describing maintenance activities and indicating the responsible party for such
activities (including signature) must be located on the document(s) submitted to the City.
o The entire project area must drain to the LID system(s). If water is flowing to the LID system
from areas outside the project area, the LID system must be designed accordingly to treat all
tributary areas. In instances where a project cannot treat the runoff from the development
area, an equivalent area may be treated as an alternative.
City of Temple City 2013
LID Small Site Technical Guidance Manual
For Commercial/Industrial LID Projects (Category 3 above)
• A Commercial/Industrial LID Project must incorporate one or more LID system(s), as found in Section
3 of this manual, in the project design. The system(s) must be shown on the plans submitted to the
City.
• Include the following statement:
As the engineer/architect of record for this project, I have designed the LID system in accordance
with the design criteria of the City of Temple City's LID Guidance Manual.
• The project engineer/architect must make sure the safety and soil stability of the LID system is
carefully evaluated prior to its inclusion in the design.
• Language describing maintenance activities and indicating the responsible party for such activities
(including signature) must be located on the document(s) submitted to the City.
• The entire project area must drain to the LID system(s). If water is flowing to the LID system from
areas outside the project area, the LID system must be designed accordingly to treat all tributary
areas. In instances where a project cannot treat the runoff from the development area, an
equivalent area may be treated as an alternative.
• Calculations must be included on the plans showing the LID system is adequately sized. A calculation
template is shown in Section 3.1. For Commercial/Industrial LID Projects, the BMP(s) must be sized
to treat the entire design capture volume (DCV).
Step 3: Plan development and submittal.
The LID system(s) design and location must be shown on the plans and submitted to the City. The
Standard Plans are available (yet not required) for guidance.
1.4 LID EXEMPTIONS
Exemptions from LID Requirements. LID requirements do not apply to any of the following:
1. A Development that only creates, adds or replaces less than 500 square feet of impervious area;
2. A Development involving only emergency construction activity required to immediately protect
public health and safety;
3. Infrastructure projects within the public right-of-way;
4. A Development or Redevelopment involving only activity related to gas, water, cable, or electricity
services on private property;
5. A Development 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;
6. A project involving only exterior movie or television production sets, or facades on an existing
developed site;
7. A project not requiring a City building, grading, demolition or other permit for construction activity.
City of Temple City 2013
LID Small Site Technical Guidance Manual
SECTION 2-COMMONLY ASKED QUESTIONS
1. I am adding a second story to my house. The existing footprint will remain unchanged, does LID
apply?
No, LID is required only where 500 square feet of soil is being disturbed.
2. I will be adding a new 500 square foot room that will replace some of my backyard. Does LID
apply?
Yes, you've crossed the 500 square foot threshold.
3. I will be building a new addition that will be over 500 square feet, but I can't fit an LID system into
the new addition. Can I create an LID system for an equivalent area of the existing building?
Yes, you can create an LID system for an equivalent area of the existing building.
4. I own a business. It is concrete and asphalt all around. Will LID be required if infeasible?
A waiver for technical infeasibility may be issued by the Director; however in this situation it is
unlikely to be granted. Generally there is always a way to implement LID requirements.
5. How big do I have to design the LID systems?
On the following pages are design criteria. Generally you have to make the systems big enough to
treat runoff from a% inch storm.
6. I am removing a 500 square foot concrete pad that is in need of repair and replacing it with an
identical new concrete pad. Does LID apply?
If the construction would not result in soil disturbance, this would be considered routine
maintenance. However, if the construction did result in soil disturbance an LID system would be
required.
7. I am installing new interior electrical and new plumbing and will have more than 500 square feet
of disturbed soil. When the project is finished, the trenches will be patched to match the existing
surrounding surfaces. The existing building will be unchanged. Will LID apply?
No, utility projects are exempt from LID requirements. See Section 1.4 of this document.
8. My project does not require any permits from the City, does LID apply?
No, only projects requiring city permits need to comply with LID.
9. If at some time in the future I want to change the design of the LID system, can I?
Only with Community Development Department approval.
City of Temple City 2013
LID Small Site Technica l Guidance Manual
SECTION 3 -DESIGN GUIDELINES AND SPECIFICATIONS
3.1 DESIGN CAPTURE VOLUME
The Design Capture Volume (DCV) is req u ired to design t he flow through planter box, v egeta t ed sw ale,
rain garden, and any other volume -based LID sys t em.
DCV Equa t ion :
1
DCV (ft3) = c X d X A X 4356 0 X 1 2
With:
C = (0.75 x Impervious Ar ea) + 0.15
d = Design S t orm. Depth (assu:me 0. 75 inch wlless otheTlA'i se known)
A = Tri butary Area
Th e information provid ed be lo w are guide lines that must be follow ed w hen designing LI D for yo u r
project. Standard drawin gs for each LI D are included for reference.
City of Temp le City 2 013
LID Small Site Technical Guidance Manual
3.2 FLOW-THROUGH PLANTER BOX
Figure 1: Flow-through planter box (http:/ /lateameffort.blogspot.com).
Design criteria for a flow-through planter box include the following:
• Design drawdown time= 48 hours (surface); 72 hours (total)
• Factor of safety= 2
• Max ponding depth = 18 inches
• Soil depth= 2 feet (3 preferred)
• Slotted PVC pipe (2 inches Minimum) within 6 inches of bottom of facility
• The area (width* length) must equal4% ofthe tributary area
• Flows my outlet to a curb drain, rain garden, or equivalent
• Cover must be dense, wet, and dry tolerant vegetation
City of Temple City 2013
SPLASH
BLOC
2' MIN.
AMENDED
SOIL
LID Small Site Technical Guidance Manual
DEPTH
,-----3" MULCH
·~
MIN.
FILTER FABRIC
(OPTIONAL,
NOTE 5)
1' MIN.
GRAVEL
SLOTTED PVC PIPE
(2" MIN, 6" MAX)
6" THICK
IMPERVIOUS
MATERIAL
BOTTOM
GENERAL NOTES:
1. DENSE, WET AND DRY TOLERANT VEGETATION.
2. PONDED WATER MUST DRAIN WITHIN 72 HOURS TO PREVENT
VECTOR BREEDING.
3. IF NEEDED, MULTIPLE PIPES MAY BE USED.
4. THE PLANTER BOX AREA (WIDTH * LENGTH) MUST EQUAL 4% OF
THE TRIBUTARY AREA.
5. FILTER FABRIC AVAILABLE AT LOCAL HARDWARE STORES.
6. FLOWS MAY OUTLET TO A CURB DRAIN, RAIN GARDEN, OR
EQUIVALENT.
DRAFT
REVISIONS CITY OF TEMPLE CITY PUBLIC WORKS DEPT.
f------1'LID-FLOW THROUGH PLANTER BOX
City of Temple City 2013
LID Small Site Technical Guidance Manual
3.3 VEGETATED SW ALE
Figure 2: Vegetated Swale (Signal Hill, CA).
Design criteria for a vegetated swale include the following:
• Design f low velocity~ 1ft/sec.
• Side slopes sha ll not exceed 3:1 (H :V).
• Slope in flow direction 1% (min) to 6% (ma x).
• Minimum bottom width= 1 foot
• Minimum swa le length = 15 feet
• Max ponding depth= 5 Inches
• Soil depth = 2 feet min
• Des ign drawdown t ime= 48 hours (surface); 72 hours (tota l)
• The area (width * length) must equa l 4% of the tributary area
• Cover must be dense, wet, and dry tolerant vegetat ion
City of Temple City 2013
LID Small Site Technical Guidance Manual
FILTER FABRIC
(OPTIONAL,
NOTE 4)
1' MIN
GRAVEL
GENERAL NOTES:
SEE NOTE 1
1. DENSE, WET AND DRY TOLERANT VEGETATION.
IMPERMEABLE
LAYER
(CONDITIONAL, NOTE 5)
2. PONDED WATER MUST DRAIN WITHIN 72 HOURS TO PREVENT VECTOR
BREEDING.
3. THE BOTTOM AREA (WIDTH • LENGTH) MUST EQUAL 4% OF THE
TRIBUTARY AREA.
4. FILTER FABRIC AVAILABLE AT LOCAL HARDWARE STORES.
5. AN IMPERMEABLE LAYER MUST BE USED IF GROUNDWATER IS LESS
THAN 10 FEET FROM THE BOTTOM OF THE GRAVEL LAYER.
DRAFT
CITY OF TEMPLE CITY PUBLIC WORKS DEPT.
f--------l!LID-VEGETATED SWALE
City of Temple City 2013
LID Small Site Technical Guidance Manual
3.4 RAIN GARDEN
Figure 3: Rain Garden (http:/ /www.prairiefirenewspaper.com/2009/04/rain-gardens).
Design criteria for a rain garden include the following:
• Design drawdown time= 48 hours (surface); 72 hours (total)
• Factor of safety= 2
• Maximum ponding depth = 18 inches
• Minimum ponding depth= 8 inches
• Soil depth = 2 feet minimum (3 preferr ed)
• If downspout is dire cted to rain garden, slope must be 2% minimum
• Cover must be dense, wet, and dry tolerant vegetation
• The bottom of the rain garden shou ld be no less than 10 feet from the groundwate r tab le
City of Temp le Ci ty 2013
BUILDING
LID Small Site Technical Guidance Manual
DOWN
SPOUT
FOR AESTHETIC
PURPOSES SLOPE CAN
v
SPLASH
BLOCK
MIN 5' OR AS
DETERMINED BY
GEOTECHNICAL ENGINEER
SEE NOTE 1
POND lNG
8" MIN.
18" MAX.
" MULCH
NOTE 3
GENERAL NOTES:
1. DENSE, WET AND DRY TOLERANT VEGETATION.
2. PONDED WATER MUST DRAIN WITHIN 72 HOURS TO PREVENT
VECTOR BREEDING.
3. BIORETENTION SOIL DEPTH 2' MINIMUM (3' PREFERRED).
4. THE RAIN GARDEN AREA (WIDTH * LENGTH) MUST EQUAL 4% OF
THE TRIBUTARY AREA.
5. THE BOTTOM OF THE RAIN GARDEN SHOULD BE NO LESS THAN 1 0'
FROM THE GROUNDWATER TABLE.
DRAFT
REVISIONS CITY OF TEMPLE CITY PUBLIC WORKS DEPT.
f------iLID-RAIN GARDEN
City of Temple City 2013
LID Small Site Technical Guidance Manual
3.5 "HOLLYWOOD" DRIVEWAY
Figure 4: "Hollywood Driveway" (Temple City, CA).
Des ign criteria for a "Hollywood" Driveway include the following:
• Recommended spacing between ribbons is 5 to 7 feet (may vary depending on expected traffic)
• Ribbon width = 2 feet minimum
• Ribbon thickness= 6 inches minimum (with mesh or r ebar)
• Ribbons should drain outward from the center of crown
• Center strip should include an irrigation line
City of Te mple City 2 01 3
LID Small Site Technical Guidance Manual
DRAIN FROM MIN. 5' O.C.
CENTER OUTWARD)~ MAX. 7' O.C
~" IN 1' CROWN) (NOTE 1)
MAX. 3'
,·-·-: -.• ... -... .,.. ~ .. '·~· ""' .. •. . -~-:. jTF'"'" ~-. "' ·~ -j 2' MIN. f-
4' MAX. PERVIOUS SURFACE (NOTE 1)
(NOTE 4)
GENERAL NOTES:
1 • MAXIMUM WIDTH AND SPACING ARE RECOMMENDED AND MAY VARY
DEPENDING ON EXPECTED TRAFFIC.
2. DRIVEWAY RIBBONS SHOULD BE AT LEAST 2 FEET IN WIDTH.
3. DRIVEWAY RIBBONS SHOULD BE AT LEAST 6 INCHES THICK WITH MESH
OR REBAR.
4. PERVIOUS SURFACE INCLUDES; VEGETATION (GRASS), WIDELY SPACED
INTERLOCKING PAVERS, AND GRAVEL.
5. DRIVEWAY RIBBONS SHALL BE CONCRETE, TRAFFIC RATED PAVERS,
BRICK, OR EQUIVALENT MATERIAL.
DRAFT
REVISIONS CITY OF TEMPLE CITY PUBLIC WORKS DEPT.
LID-SEMI-PERVIOUS DRIVEWAY
City of Temple City 2013
LID Small Site Technical Guidance Manual
3.6 BOTTOMLESS TRENCH
Figure 5: Bottomless trench (http:/ /www.cob.org/services/environment/water-quality/).
Design criteria for a Bottomless Trench include the following:
• Trench width= 24 inches (across driveway)
• Trench depth = 18 inches
• Bottom 8 inches of the trench must be filled with crushed rock
• Trench must be at least 12 inches from back of sidewalk (or edge of pavement in the case of no
sidewalk)
• Longitudinal width= 6 inches (along driveway)
• Fram e and grate must be pedestrian safe
City of Temple City 2013
LID Small Site Technical Guidance Manual
PEDESTRIAN SAFE---...
FRAME & GRATE
(SEE NOTE 9)
CRUSHED ROCK
W/FILTER CLOTH
GENERAL NOTES:
DRAFT
SECTION A
PLAN VIEW
~-DIMENSIONS
VARY (NOTE 7)
o+----,.,..--#4 REBAR
TOP & BOTTOM
CRUSHED ROCK
OPTIONAL PERFORATED
PIPE TO ADJACENT LAWN
NOTE 7
1. TRENCH SHOULD BE 24" WIDE (ACROSS DRIVEWAY) X 18" DEEP.
2. PRECAST MAY BE USED.
3. FILTER CLOTH MUST BE PLACED IN THE TRENCH EXTENDING 12" VERTICAL.
4. BOTTOM 8" OF THE TRENCH MUST BE FILLED WITH CRUSHED ROCK.
5. DIMENSIONS DETERMINED BY GRATE FRAME DIMENSION. USE FRAME AS A FORM.
6. MUST BE APPLIED AT LEAST 12" FROM BACK OF SIDEWALK OR EDGE OF
PAVEMENT IN THE CASE OF NO SIDEWALK.
7. MINIMUM LONGITUDINAL WIDTH (MEASURED ALONG DRIVEWAY) OF FRAME & GRATE
IS EQUAL TO 6" WITH %" SLOT OPENINGS. EAST JORDAN IRON OR EQUAL.
City of Temple City 2013
LID Small Site Technical Guidance Manual
SECTION 4-REFERENCES
The Los Angeles County Low Impact Development Standards Manual at:
http:/ I d pw.lacou nty. gov jwmd/ dsp _Low I m pactDevelopment. cfm
The City of Los Angeles Low Impact Development Best Management Practices Handbook at:
http:/ /lacitysan. org/wpd/Siteorg/ program/LI 0/lidi ntro. htm
Please note that the City of Temple City's LID ordinance takes precedent in the event of any
inconsistencies with any outside references.
City of Temple City 2013
Attachment C
C'it.y of Temple City
Green Streets Manual
October 2013
Green Streets Manual
TABLE OF CONTENTS
Section 1-Introduction ............................................................................................................................... 1
1.1
1.2
1.3
What are Green Streets? .............................................................................................................. 1
Why are Green Streets being required? ....................................................................................... 1
1.3.1
1.3.2
1.3.3
1.3.4
1.3.5
Planning and Development .......................................................................................................... 2
Site Considerations ....................................................... ~.:.:. ................................................... 2
Design Considerations ........................................ ,d{t.:·!.~ ...................................................... 3
BMP Sizing for Applicable Green Streets Projg~i~!i!'v0J.~c:, .................................................... 4
Alternative Compliance Options for AppJi~!J~fi?~reeng~~~~t? Projects .............................. 4
":-:;::-:::.>t<:>r-----'-':\·. ><: ,::>;_
Infiltration Considerations ............... ;;}:,,:,,:: ........................... :\•!;?: ........................................ 4
Section 2 -Infiltration ........................................... '~;~}; •.................................. ~ ..... ;;:,•: .................................. 8
2.1
2.2
2.3
Infiltration Trenches and Dry Wells ............. ''.'.i;),;;,, ....... ,,:{,'-\') .................. '-.~?;);:,., ........................ 9
Rain Gardens ....................... ::totfb •....................... i:~.g~::ff:~s.~ ........................... '::f'!!: .................... 10
Permeable Pavement .............. i~12.:J.'.:7t:~: .................. '·:.~iG'!: ......................................................... 11
Section 3-Biotreatment. ........................... :~.+~:., .. '~5.1:i~Jv,;c,,., ......... ·.;;;,;;i:i, ................................................ 13
3.1
3.2
3.3
3.4
B io retention ..... ,;,(~f.i7Slt:·, ................. !:if:.. .......... :.~,,,:~''''· ........... !:;!,.;, ........................................... 13
Flow-Th ro ugh,~l~~{~;s .. !-'.:,~,., ............. ·i: .. ;:,.:c:JJ!:.'~.' ....... ~}~!.::: '· .... : ............................................. 14
vegetated s~~i;s ............... S. •.• 'i ................ ::HcF.' ......................................................................... 15
Veg~t~ted. Buffe~~~;j'p~ .. ,;:.~.'i.;:.~:;, •............. ';is;, ........................................................................ 16
Section 4,;:ff~~t;;;~ri{/8MPs .... '::::~ft\'t ...... ~.? .. ~3;;(,;;, .......... ·: ..................................................................... 16
4.1 \'·~~~d Filters &~{6imDrai~1l~!et Protec~io~~ .. ~ ........................................................................... 16
Section ~~;~tfeet Trees ......... :.~.;;, ........... ':.::~: ............................................................................................ 18
5.1 Str~'Zt1trees ............... '::z':::. ........ • .. :<.:! ........................................................................................ 18
section 6-Defin;~i8ri~: ................... t!irL ..................................................................................................... 19
Section 7-Reference~~ •. !.;, ...... ,;,}} .. /.. ...................................................................................................... 20
City of TEMPLE CITY Table of Contents October 2013
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 gial~ and benefits. Using the right-of-
way for treatment of stormwater runoff links green with gr~~\')]1frastructure by making use of the
engineered conveyance of roads and providing connections t!ii~6Jiyeyance systems when needed.
Green streets are beneficial for new road constructi,9~ '~"gi:l'retr6fit~~, They can provide substantial
economic benefits when used in transportation{a,'~~ljcations. Co~~~i,?ating green infrastructure
installation with broader transportation improve'n)~j~'tan reduce the cdst,8J,~tormwater management
by including it within larger infrastructure impro\(:~~ents. A large municirmtm~cern regarding green
infrastructure use is maintenance access; usint:;~lJ,JJ;ds and fi?pt-of-waysil~~;;)~cations for green
infrastructure not only addresses a significant poflij~~!lt ~~:\JtSe, but also alleXi,~tes access and
maintenance concerns by using publj§;TFsp£1ce. Also, rigllt~of,lM~Y installations alfow,~'for easy public
maintenance. ';~;~,~:,§~ :;, , ";;~••
Green streets can incorporate a wide ~fft~ety ~f}q,e~i~n elem~~t~, including street trees, permeable
pavements, bioretention, a~,cl:~\1/ales. Alttl~~~h the ~ii'~f~n ~nd app~a~~nce of green streets will vary,
the functional goals are W:;;~,affi~"~Brovide sour5'7:contro,J5'tlif~r~\\/at~r;J,imit its transport and pollutant
conveyance to the cp(l~§{lon syst~f,l)< restorepr:e;~~y~Jopme[lt;;,~ydrology to the maximum extent
practicable, and provid~ epvironmen~~Hy enhanc~4,,~pa'ds. Successful application of green techniques
will encourage soil and v~g¢tation COQt~ct and infiltnhion and retention of stormwater.
1.2 w!i.Y'~ii~'t:;IulEN st&E~tsaEI~G.REQUt)lEo?
This G;~~~{{treets M:~~:i~rqyid:~J~~~ac~ce to'~~~~lywith the MS4 Permit (Order Number R4-2012-
0175) whi~I'J-re,quires that jur~gktions fn,J.'p7.Angeles County reduce contaminants in runoff to improve
water qualityin;'o/oterways. The§~Iequireiil~bts stem from the National Pollutant Discharge Elimination
System (NPDES)r~quirements ofti'J~:Ciean W~ter Act (CWA).
The MS4 Permit ;~~'(;iJ~~ Gree~,;~t~eets strategies to be implemented for transportation corridors.
Transportation corridors·~~.~re~~!l}ia" large percentage of the impervious area within Los Angeles and
therefore generate a substa.p!I,al;.afnount of runoff from storm events. The altered flow regime from
traditional roadways, increa~e{( 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 Temple City Page 1 October 2013
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. lmpervio~.~):'?urface replacement, such as the
reconstruction of parking lots and roadways which,,\1?:.f!5.>not disturb additional area and
maintains the original grade and alignment, is c~.!!)il~~~~d a routine maintenance activity.
Redevelopment does not include the repaving of;~~f~'tings;F?:~ds to maintain original line and
grade <> ,~/ """"?;
3. Stree~ and road improvement with a cost of$.SQQ;ooo or more.•"'
Table 1: Examples of Stormwater Pollutants Typical of Ro~,~~-~:1~~,~-aging Wet Weather''''J;;f~':c;r~en Infrastructure Municipal
Handbook: Green Streets~ 2008).
Pollutant
Trash
Sediment/solids
Metals {Copper, Zinc, Lead,
Arsenic)
Organics associated with
petroleum (e.g., PA~.~L
Nutrients
1.3
Source
Littering
<---, "/''
Construction, unpaved a-·~:~-~~\,
,·· !<:~~r:;:;~,-; P'hYsical damage to aquat(2\i~imals and fish,
:· ,;;'!::-r_~,lease of poisonous substances
<, tr;:~:f!;;,~sed turbidity, increased transport of soil
bOti_:~:~L-~~~IIutants, negative effects on aquatic
organi~_fD$Jeproduction and function
Toxic to aquatic organisms
Promotes eutrophication and depleted dissolved
oxygen concentrations
Ideally, a site~~ul.9 be design:~>i~capt:;~·~hd use or infiltrate the entire runoff volume of a storm,
however site and d~sig,n constraint~~J;nake it difficult to achieve that goal. This Green Streets Manual is
designed to provide gujqance ";'iJ~TllMP selection based on site constraints typical to street design.
Streetscape geometry, 'tqppg(jlphy, and climate determine the types of controls that can be
implemented. The initial 'st~.J?.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
City of Temple City Page2 October 2013
Green Streets Manual
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.
•
•
•
•
1.3.2
Grade differential between road surface and storm drain,s'(stem. Some BMPs require more
head from inlet to outlet than others; therefore, allmA/abfe,:head drop may be an important
consideration in BMP selection. Storm drain elevatipo~:n\ay be constrained by a variety of
factors in a roadway project (utility crossings, outfrj!i,rlf~~-f,i,(lns, etc.) that cannot be overcome
and may override stormwater management considefatlons'::·'·
Longitudinal slope. The suite of BMPs whi,c~~~ij ~~ installed~Si\'~i[eper road sections is more
limited. Specifically, permeable pavem~p.~;'ahd swales are more $~itable for gentle grades.
Other BMPs may be more readily terraced'{o qe used on steeper slop'er.
Soil suitability. Infiltration BMPs require iS~'~ifi~ tyP;r#:%f: soil. Thesii~ ossessment should
determine the type of soils onthMite and the infiltratiq~rate of the soils if infiltration BMPs are
:~::::~a~·access opportunities.1 ~~~~~~fW~~n~spncer~t!i~~-P~~allation of BMPs in major right of
ways is the abilitytp,safely access;~he BMP~\;t9S mainte[l<l9_ce considering traffic hazards.
Vehicle travel l~p~~ill:?-?yp.~cific areasp~tentia11~tl)a~.a~;~ous fo;_maintenance crews should be
identified during 1We site•affisissment. J~~ ~f~~n Streets \1\fQIVlP should provide subsequent
steps to avoid plilbing BMP; ipJhe identifi~dbaza~dous areas;
Design Consid~i~\:i'i:m.s
The draina~~Jl~tf~f:!l~pfthe'ti~)~~~!~h~'dld~~B~~elo'~~1 •• so that drainage can be routed to areas with
BMP oi:>pprtunities befor~;~ntering;;st()rm drai~s:,;.-~(1{ ~xample, if a median strip is present, a reverse
crown shpl.J)d be considered~;~.?ere''all()\li{ed, so thafstormwater can drain to a median swale. Likewise,
standard rieak;flow curb inlet~Jnould b~_l_o~ated downstream of areas with potential for storm water
planters soth?t;\,\later can firstc,fl?w into tlje, planter, and then overflow to the downstream inlet if
capacity of the pl~9ter is exceed~<f; It is more difficult to apply green infrastructure after water has
entered the storm d~ain. · · ··
Green Streets projects~te'npt~?qw~~d to treat off-site runoff; however treatment of co mingled off-site
runoff may be used to off-set'~he inability to treat areas within the project for which significant
constraints prevent the abilityt6'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.
City of Temple City Poge3 October 2013
Green Streets Manual
1.3.3 BMP Sizing for Applicable Green Streets Projects
An 85th 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 andcq!l)pute imperviousness.
2. Look up the recommended sizing method for the ~M~2:§:~1ected in each drainage area and
calculate target sizing criteria.
3. Design BMPs per a published design standanj,:''
4. Attempt to provide the calculated sizing (:dt~(j'~tfor the selected ~11/l~~;
5. If sizing criteria cannot be achieved, docuitl~n~the constraints that ~ve[~id~. the application of
BMPs and provide the largest portion of the sizif}~frite,(\~l.t/iat can be reason~21y provided given
constraints. If BMPs cannot b~~~if~gto provide tne£,~!~g)ated volume for thetributary area, it is
still essential to design the BMg;;in)~j;ztnergy dissil?~t~?n, and overflow capacity for the full
tributary area to ensure that fldQ,Q\flg ancJ ss~ur is ;vbj~ep. It is strongly recommended that
BMPs which are designed to less t~~.fl theirtl![g~t design\fpl!!me be designed to bypass peak
flows.
1.3.4 Alternative co'~~N~~~~pptions f~S:~ppli~~~{~~~~~A Str:~ts Projects
Alternative complianci'~~ggrams s~S:~ip be consid~~~~· for applicable Green Streets projects if on-site
green infrastructure approar;bes c~g~BlPf~cticably tr~at the design volume. The primary alternative complianc7·9B~igp,\q.r.applic~tit~,qr3~fl St~~~5s,eroject~:).~the completion of off-site mitigation projects.
The pr~pop~nt Wbu1q i;r)glemen!•;,a project to•r<;!quce.stormwater pollution for other portions of
roadwaygrsimilar land ~s~~ •• when§fl;~i2g reconstrl)~ted to the project in the same hydrologic unit,
ideally as aose to the proje~t'as possible and discharging to the same outfall.
1.3.5
"-,,,,, ,, Intill:f'~l:ion Considei~ilons
Appropriate s:·;~~~·•jl)fjltration mJ~i<j, and infiltration rates should be used for infiltration BMPs. If
infiltration is proposed;· a complefe .. 'geotechnical or soils report should be undertaken to determine
infiltration rates, grou'l'lJ\}v.aterf!~~th, soil toxicity and stability, and other factors that will affect the
ability and the desirability'7oJJn,filtration. At a minimum, the infiltration capacity of the underlying soils
shall be deemed suitable for infiltration (0.3 inches per hour or greater), appropriate media should be
used in the BMP itself, the groundwater shall be located at a depth of ten feet or greater.
City of Temple City Poge4 October 2013
Green Streets Manual
Figure 1 : BMP Selection Flow Chart.
City of Temple City
l'es
Det~rmine ifGrec.'n Srre~c.; is
Appiicai.lle
Do~s th~ Project im•o/1·e a
Trnn sportr:cion Co rririo1'?
Does one ojti:e Foliowin.!J Ap p(y:
No
1. Cos t at L~a st 5500,000?
2. New De\•elopmenrojlO,OOOsforMore:
4 (;ra n Struts Doe; Nor Appi
3. P.ede\•eiopn:el :tof5,000sforMore ?
~----~~~~~-~
iVo
Green Streets Develovmet:t
Projecr · ......_ ~ rreenStreers Does NorAppi
'\ \
Duumine Sit.• Conditions
and Con straints
Jnfiltrrrtion Feas ible
I)
Infiltration Jnjensii.lle
4 Implement lnjiin·otion BMP AssessSpr.ce A\•aiiclille for
Biott~(ltnh'nc BMP.s
Biotrt'r.tmenr Fr:tu iiJle
/mf)ft'mt'nt Biccr~atmt.'llt
. BMPs
PageS
Bion·entmmt Infeasible
4l1mp!t•ment Treatment BMPs
(SaSrccio n.J)
October 2013
Green Streets Manual
Table 2: BMP Selection by Street Context (Mode/for Living Streets Design Manua/1 2011).
Commercial
Residential
Industrial
And
MixedwUse
Special
Small
STREET
CONTEXT
Downtown
Commercial
Commercial
Throughway
Neighborhood
Commercial
Downtown
Residential
Residential
Throughway
Neighborhood
Residential
Industrial
Mixed~Use
Sidewalk
Furniture Zone
Park Edge
Boulevard
Ceremonial
(Civic)
Alley
Shared Public
Way
Walk Street
Swales
.,
.,
.,
.,
.,
., .,
BIORETENTION
Planters ! Vegetated
i Buffer Strips .,
., .,
., .,
.,
.,
.,
.,
I
., .,
.,
., .,
!' .,
./.;
City of Temple City
L:c
I
Rain Gardens
.,
DETENTION
i Infiltration Trenches
& DryWPII<;
., .,
., I
PAVING
Permeable
Pavement .,
.,
.,
Storm Drain
Inlet Screens .,
.,
.,
.,
.,
INLET PROTECfiONS
Storm Drain
Filter Inserts .,
.,
.,
.,
.,
., -I ., ., .,
., .... <> ., ., ., ., ., .,
., ., ., .,
., ! >==-o·-., ., .,
.,<<· ;·<' ., ., ., ., ., .,
., ., ., ., ., ., ., .,
., ., ., .,
Page 6 of22 September 2013
Pipe Filter
Inserts .,
.,
.,
.,
.,
.,
., .,
.,
., ., .,
., .,
.,
Green Streets Manual
Table 3: BMP location Opportunity Summary.
BMP
Bioretention
Infiltration Trench/Dry Well
Rain Gardens
Permeable Pavement,,
Location Opportunity Summary
• 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 locati9os'
• Can be located under si<Jll§i~;fl(~~~d in sidewalk planting strips, curb
extensions, roundabout~;~~(! ~'e~'fans
• Can be integrategit{~'~i~ns, islands, ~l~~l~s,,street ends, chicanes, and
curb extension;'',(~''
• Can be located }~~~t~rmin>ts'~f'swales int~~l~nd~cape
• Can be ~~~i!t~ctihtu.nJiture zoA~s'ofsidewalks especially adjacent to
tree wells' , ,
• ~~~.not be ~:£2ed ifi,a~i~~:rt~ large't;~ffic volume or heavy load
lane~ , , ,
>(-:\ ',', '•;;
• AVgld stl!ep street~:,.~
h ... ;. ;;; J})i\; ; : ::::::::::::~::,: :·:~:::::::::::b~"m'""
Flow-Through
Vegetated Swales
City of Temple City
:·'?:). f.:: :'L .. >:':
··~~ove-graae planters should be structurally separate from adjacent
sidewalks
·<·'
,,,.• 'tt-grade planter systems can be installed adjacent to curbs within the
''<1 , frontage and/or furniture zones
• 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
Page 7 af22 September 2013
Vegetated Buffer Strips
Treatment BMPs
Street Trees
Green Streets Manual
• Should be designed to work in conjunction with the street slope
• Can be located in multi-way boulevards, park edge streets, or
sidewalk furniture zones
• Can serve as pre-treatment
• Can be located in a catch basin, manhole, or vault
• Can be installed on an existingo4tl!jt pipe or at the bottom of an
existing catch basin with an ov~if!<iw
• Can be placed on existin~'~J~t~~~~:cqtch basins and flush grate
' ''" ' '"'!·\
openings
• Can be installe~·~W;¥~:~xisting wall of~\~~\ch basin and on the curb
side wall of a ci3t~hbasin ·
• Mini.~y~ set-bac:·:;t~~J!,]if.9UD~~t~ns and slo::~~~oyld be observed
if the. BI\IIP is not lined
• Can bgpfat!O!({;qgsidewalk{in!.f!Jrniture zones, and on medians
• Adequat~.SP~2in~m.y?t be proV\!J~2.between trees and street lights,
.••. •···.··· .. · .. ··. pedestrian.li~hts, acc!i~~.!~!.~parking~B~ces, bus shelters, awnings,
• .• >• canopies, balcqnies, <~ncJ.si~n$ ·
SECTION 2 -IN;1~TRA~fON
lnfiltra}i9~·.~~~~~}·~~iliz~·r9c:,!~~~~l,:~~~th~iRj&h~~;·J~rmeable materials for on-site infiltration. In
these sysi~~s, stormwatertqr?ff is ciir~cted to the system and allowed to infiltrate into the soils for on-
site retentipn •. ?nd groundwat~r:~~charge;•.[)~ring small storm events, infiltration systems can result in
significant or even complete volqll')e reductipn of stormwater runoff.
Infiltration sho~l·d.·.'~e used to tB~' maximum extent practicable. Biotreatment BI\IIPs should be
considered if infiltrati?J1. is foun9+J<! be infeasible due to low infiltration rates, soil instability, high
groundwater, or soil contam.ination.:•
Infiltration BMPs may be~J~~.~~rrlaged 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.
City of Temple City Page8 October 2013
Green Streets Manual
2.1 INFILTRATION TRENCHES AND DRY WELLS
Figure 2 : 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 Rrovide 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 haye 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 reauction 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.
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.
City of Temple City Page9 October 2013
Green Streets Manual
Perforated pipes and piped inlets and outlets may be included in the design of infiltration trenches.
Cl eano uts should be installed at both ends of any piping and at regu lar i ntervals 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 shou ld be
properly des igned for anticip ated f lows.
2.2 RAIN GARDENS
Figu re 3: 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 unl ess t he volume of water is so large that
some must overflow. Rain gardens ca n reduce or eliminate off-site stormwater discharge while
increasing on-s ite recha rg e.
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 ca l ming measures installed along st reets,
such as medians, islands, circles, street ends, chicanes, and curb ex tensions. Rai n garde ns are often
used at the terminus of swa les in the l andscape.
City of Temple City Page 10 October 2013
Green Streets Manual
2.3 PERMEABLE PAVEMENT
Figure 4: Permeabl e pavement duri ng a storm event (Model
for Living Streets Design Manual, 2011}.
Description
Permeab le paveme nt is a system with the primary purpose slowi ng or el iminating direct runoff by
absorbing rainfa ll an d al l owi ng it to infiltrate into the soil. Permeable pavement also filters and cleans
pollutants such as petro leum deposits on streets, reduces water volumes f or ex i sting overtaxed pipe
systems, and decreases the cost of offsite or ons ite downstream infrastructure. This BMP is impaired by
sediment-laden run-on which diminishes its porosi t y. Care should 1:5e taken to avoid flows from
landscaped areas reaching permeable pavement. Permeable pa~ement is, in certain situations, an
alternative to standard pavement . Conventional pavement is designed to move stormwater off-site
quickly. Permeab le pavement, alternative ly, accepts the water where it falls, min imizing the need for
Location and Placement Guidelines
1 '~j
-------Varies---------+
I
I
I
Sid ewalk
'1--
Pervious 1 Sidewal k
pavement 1 ~ ~
. ··~: ~ :.'J ~:: ,,~.~ ~~·,_:-_ -.---------------~ .. _.:·:··,!_,~ •. ·.::.· .. !.111-.~.:.l_··.~ .• :-·_ ··~---~-~-~.-~_:_;_··-~7!~~-~~-~_:_!~~.}.")W$'$ : ·~~=:-!·. ;:'.~~--::':~~: P,)'/'f, Utllityand::~:struc ture ••
Figure 5: Possible pervious pavement design layout (Model for Living Streets Design Manual, 2011}.
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 sidewa lks especially adjacent to tree we ll s
City of Te mple City Pag e 11 Oc tober 2 01 3
Green Streets Manual
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 conductedJq"~f6~ide informatio~;;~~~~t the permeability rate of
the soil, load-bearing capacity of the soil, the dept).li~o groundwater (10 feety~more required), and if
soil will exhibit instability as a result of implement~·1\?n. lnfilt~ftion rate antJ!gfd capacity are key
factors in the functionality of this BMP.Permeable pa\f~.lDen~.~eg~rally does nofba.ye the same load-
bearing capacity as conventional pav~fl'!-~Rol,so this BMP @~y·>p~ve limited applications depending on
the underlying soil strength and pavetJJ.~~t·~?~z Permeable"p~~ement should not be used in general
traffic lanes due to the possible variety ofve.hlcl"e:$s\ll{~ights and h!i~VY volumes of traffic.
When used as a road pavin~,p~rmeable~~~:~~~f~h~].c~rriesii"~~t.,traffic loads typically has a thick
drain rock base materiaL:r~¥~f~~.hould be C:o:~s:ete a,~pPPp~~flto brj~~ or other light-duty materials.
Other possible perme~q!e)pavln~ l!).aJ~rials inclu9~oP8f8Y.s eo~tr~t~ and porous asphalt. These surfaces
also have specific basefu;~terials that"(l~tain infiltra!~~.).\iater and provide structure for the road surface.
Base material depths sho\Jl~.qe specifj~(J based on dg$ign load and the soils report.
Plazas, em:Fg~nB~\C()?~s, a~d dt2tf~t~~~·o)1Jj,l"!)ited$~~isular access can also be paved with permeable
pavemegt,:c ~avi~g mat~ri~ls for \tl~~e areas m~)':if1~lucte open cell paver blocks filled with stones or
grass amt)llastic cell systert}§· Base 1]"1<Jterial speCifications may vary depending on the product used,
design lo~(J)and underlying soil~.· · .. .
When usedf(}t"p~destrian pat.~s~~~idewal~~iapd shared-use paths, appropriate materials include those
listed above as w¥1J 9s rubber P~lf~5s and d~~omposed granite or something similar (washed or pore-
clogging fine matefifll.,_ Pedestr).~Jl paths may also use broken concrete pavers as long as ADA
requirements are m~f.J'~t~s shq~l(J"ctrain into adjoining landscapes and should be higher than adjoining
landscapes to prevent ruh7Q,Qf.~~avement used for sidewalks and pedestrian paths should be ADA
compliant, especially smootH;~nt( not exceed a 2 percent slope or have gaps wider than 0.25 inches. In
general, tripping hazards should be avoided.
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 eourse;
• 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.
City of Temple City Page 12 October 2013
Green Streets Manual
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 infiltratio n 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 stormwa te ~ treatment dev ice that are installed
at curb leve l and filled with a bioretention type soil. They are aesigned as soil and plant-based f iltration
devices that remove pollutants t hrough a variety of ptiysical, 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 infeas ible due to low
inf iltration rates, soil instabil ity, high groundwater, or soil contami nation.
3.1 BIORETENTION
' -
Figure 6 : Bioretention system (Model fo! Living Streets Design Manual, 2011}.
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. Eac h component of the
bioretention BMP is designed to assist in retain ing water, evapotranspiration, and adsorption of
pollutants into the soil matrix . As runoff passes through the vegetation and soil, t h e combined effects of
f iltrat io n, absorption, adsorption, and biological uptake of plants remove pollutants.
City of Temple City Page 13 October 2013
Green Streets Manual
For areas with low permeability or other soil constraints, bioretention can be designed as a f lo w-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 t he storm drain
system, or may treat the water exclusively through surface flow. Examples of bioretention BMPs include
swales, p la nters, and vegetated buffer strips .
Location and Placement Guidelines
Bioretention fa ci lities 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 in to curb extensions,
medians, traffic circles, roundabouts, and any other landscaped area . Depending on the feature,
maintenance and access should always be considered in loca ting the 9evice. Bioretention systems are
also appropriate i n constrained locatio ns where other storm~te facilities requ i ring more extensive
subsurface materials are not feasible.
If bioretention devices are designed to include infiltratjon, 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 s.tormwater management approaches or specia l
engineering.
Figure 7: Flow-through planter (Model for Living Streets Design Manual, 2011}.
Description
Flow-through planters are typicaiiY'above-grade or at-grade with sol id wa ll s 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 su rfa ce overflow drains are typically installed with building-adjacent
planters.
At-grade street-adjacent planter boxes are systems des igned to take street runoff and/or si dewalk
runoff and incorporate bioretention processes to treat stormwater. These systems may or may not
include un derdrains .
Location and Placement Guidelines
City of Temple City Page 14 October 2013
Green Streets Manual
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 po nd 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
f low in to 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 8: 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.
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
City of Tem ple City Page 15 October 2013
Green Streets Manual
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
Figure 9 : Vegetated buffer strip detail (Model for Living Streets Design Manual, 2011}.
Description
Vegetated buffer strips are sloping planted areas designed to t reat 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 Guid elines
Vegetated buffer strips are well-suited to treating runoff from roaas and highways, small parking lots,
and pervio us surfaces. They may be commonly used on multi-way boulevards, park edge streets, or
sidewalk furnitare zon es with sufficieot space. When selecting pote ntial placement the need for
supplemental irrigation shou ld be considered. Vegetated buffers can also be situated so they serve as
pre-treatment for another stormwater management feature, such as an infiltration BMP.
SECTION 4 -TREATMENT BMPS
4.1 SAND FILTERS & STOR~ 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 rainstorm s. 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
City of Temple City Page 16 October 2013
Green Streets Manual
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 such that ponded water
should not persist for longer than 48 hours following a
• Cartridge Media Filters: Cartridge media filters
engineered media. The filters can be located in
modular filters which contain
or vault may be divided into multiple cham~,~?~ chamber may act as a pre-
settling basin for removal of coarse sedirJ],J;f\tfjihile the next''~_l\@) may act as the filter
chamber. Cartridge media filters are re_cR;v·mended for with limited available
surface area or where surface BMPs &','d~id restrict uses. the number of
cartridges, maintenance events can have t6'r\~~;~,u,ration~,.~,;~ocations s chosen so that
maintenance events will not si?.~:ficantly disrJp!;;2~,~~ifl~$~~s· or traffic. rts should be
sized to capture all debris and ~ry~¥~~-:therefore be's~~~&Jiid to match the 1 size and shape
of each catch basin and inlet. Fi'tt~{rii~g.i~should be~'l;J~~,ted to target pollutants of concern. A
combination of media may be u~~.9,to•·r~lJJqye a varfe¥t'<gf pollutants. Systems with lower
maintenance requirements are prefe:fr~d. ·. . ··
• Storm Drain l~l~i?~'?fi!'J~~<J;>Inlet scr~~p~ar~,q~~ighep.tpp;eV~ht large litter and trash from
entering the s~?~~ drainsvs1*rn while allq,¥'!1~\lsrnallerfl~rJicles to pass through. The screens
function as the''t~~tpreventl~~2 measure in,f~rr10ving pollutants from the storm water system.
The city's street sW~:~ingd~fi~~:~rnent shoiJ;I~be consulted to ensure compliance with local spe8ifil;:~~~9Q.~ ~~d i(),~F~~,~t(e:r~~~~~r mal~t~a.ance. Annual inspection of the screen is
r~~:0ir)rrleni:fe41it~, ~nsu~ettg!J:tionality. :~,C>!;e that most LA River drainage areas are already
••pr()tected using col)n<;ctor pihescreens through collective systems.
Storm D;~m'l'i,~e Filter lnse~f~~;T~~st~i~i~f~in outlet pipe filter is designed to be installed on an existing
outlet pipe or.,~~:·~he bottom d{~q,existingi~~ptch basin with an overflow. This filter removes debris,
particulates, and'~\ryer pollutant;•f~$,m stormWater as it leaves the storm drain system. This BMP is less
desirable than a prb{~Etion systern',~pat prevents debris from entering the storm drain system because
the system may becom~:f19gge~ )!1\t~' debris. Outlet pipe filters can be placed on existing curbside catch
basins and flush grate ope,~j~gs,,,:~egular maintenance is required and inspection should be performed
rigorously. Because this filter,i~;Jocated 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.
City of Temple City Page 17 October 2013
Green Streets Manual
SECTION 5 -STREET TREES
5.1 STREET TREES
Figure 10: Street trees (Temple City, CA).
Description
Healthy urban trees are powerful stormwater management tools . Leaves and branches catch and slow
rain as it fa ll s, helping ·it to soak into the ground. The plants themselves take up and store large
quantities of water tliat 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 providea with conditions that allow them to thrive, including adequate
uncompactec:boil, water, and air.
The goal of adding street trees is to increa se 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 coo ling air, producing oxygen, and absorbing and stori ng carbon in
woody plant tissues
City of Temple City Page 18 October 2013
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 Treated runoff is then
slowly infiltrated and recharges the groundwater.
Conveyance
The process of water moving from one place to anothep;; ..
/', <~'{:'~->~':
~e::;~~t::Se magnitude, rate, and intenSity a~:~~~~ eXCeed the design IUdY;IIU a storm drainage
system or flood protection project.
Detention
Stormwater runoff that is collected a~'i~~~~~te.and then·~~~.~:;,~ed at a controlled rate. The volume
difference is held in temporary storage.
\:>-:: ' ':::',>X:c:': ;--:_:,:,·:, ·--· ... · .. :,:; .~.<: >
Filtration . < )' y ..••. , ·•· · C, . ,<i?, . · i
A treatment process t~~f~}iovisf0~'0moval ofs~Ji? (p~rtictilate)rn.atterf;om water by means of porous
media such as sand, soJl;.yegetation;9r,a man-mat[eJifi:e'r~ Filtration is used to remove contaminants.
Furniture Zone ··.··········· •'?~&\,·:.......... ..< ~rfJ,.,......... >'.fr\,
The furnitYff!'.~?PE!·J~<lhe area;,\:\(~ifhliesbet)Ngen th~·~urb and pedestrian zones and is intended to
house util\tiesandpede~frian amenities. . . . .· .
Hardscap~··········•··· ····•.·· ......... ,........ . '. lmpermeable~~~aces, such as'cqp,prete orJtone, used in the landscape environment along sidewalks or
in other areas use'i;l as public spate.'
Infiltration
The process by which wa~~rpenetr~l:~s 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.
City of Temple City Page 19 October 2013
Green Streets Manual
Sedimentation
The deposition and/or settling of particles suspended in water as a result of the slowing of the water.
Storm water
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 Desigf)~lfd,nu<JI.
2. U.S. Environmental Protection Agency
Municipal Handbook: Green Streets.
3.
City of Temple City Page 20
Green Infrastructure
October 2013
Attachment D
Planning Commission
Staff Report
October 17, 2013
Item No.: 7B
FILE NO:
APPLICANT:
PROJECT PLANNER:
ENVIRONMENTAL REVIEW:
RECOMMENDATION:
Background:
Municipal Code Amendment -Low Impact Development Standards
and Green Streets Policy
A request for a Municipal Code Amendment to amend Article E (Site
Plan Review and Congestion Management) of Chapter 1 (Zoning Code)
of Title 9 (Zoning Regulations) of the Temple City Municipal Code to
establish Low Impact Development Standards and Green Streets Policy
City of Temple City
Hesty Liu, A!CP, Associate Planner
Andrew Coyne, Management Analyst
Staff has determined that the project is exempt from environmental
review in accordance with Sections 15061(b)(3) and 15308 of the CEQA
Guidelines.
Adopt Resolution No. 13-2382 and recommend that the City Council
approve Ordinance No. 13-979 for the establ'lshment of the City's Low
Impact Development Standards and Green Streets Policy
Low Impact Development "consists of building and landscape features designed to retain or filter
stormwater runoff". These treatment systems work to reduce pollutant levels and 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 parcel's landscape theme.
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. Green infrastructure
approaches also complement street facility upgrades, aesthetic improvements, and urban tree canopy
efforts. Further, using the right-of-way for treatment of stormwater runoff can link green with grey
October 17, 2013, Planning Commission Meeting
Staff Report-Item No. 7 B
File No.: LID standards and Green Street Policy
infrastructure through making use of the engineered conveyance of roads and providing connections to
conveyance systems when needed.
On November 8, 2012, the California Regional Water Quality Control Board, Los Angeles Region
adopted the Municipal Separate Storm Sewer System (MS4) Permit (i.e., Order No. R-2012-0175). The
Order requires that Permittees (e.g., cities) electing to prepare a Watershed Management Program or an
Enhanced Watershed Management Program "demonstrate that there are LID ordinances in place and/or
commence development of a Low Impact Development (LID) ordinance(s) meeting the requirements of
this Order's Planning and Land Development Program within 60 days of the effective date of the Order
and have a draft ordinance within 6 months of the effective date of the Order." The Order also requires
Permittees to have green streets policy(ies) in place and/or commence development of a policy(ies) that
specifies the use of green street strategies for transportation corridors within 60 days of the effective
date of the Order, and a draft policy is prepared within 6 months of the effective date of the Order.
The overarching goals of imposing Low Impact Development Standards are: (1) reducing the amounts
of pollutants in stormwater and urban runoff, (2) development of 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.
The overarching goals of adopting Green streets policy are: (1) providing source control of stormwater;
(2) limiting its transport and pollutant conveyance to the collection system; (3) restoring pre-
development hydrology to the maximum extent practicable; (4) providing environmentally enhanced
roads. Successful application of green techniques will encourage soil and vegetation contact and
infiltration and retention of stormwater.
As one of the participants of the Enhanced Watershed Management Program (EWMP) of the Upper Los
Angeles River Watershed Group, the City of Temple City (i.e., a permittee) is required to comply with the
MS4 permit's mandate and deadlines.
ANALYSIS:
Low Impact Development Standards
To comply with the MS4 Permit mandate, the City of Temple City must establish Low Impact
Development standards and a Green Streets Policy, in accordance with the regional board
requirements. There are four LID categories:
Category 1.
Category 2.
The project will disturb less than 500 square feet of soil
The project is exempt from LID requirements.
The project is residential, will involve 4 or less dwelling units and will disturb more than
500 square feet of soil
The project falls under the Residential LID Category.
Page 2
October 17, 2013, Planning Commission Meeting
Staff Report-Item No.7 B
File No.: LID standards and Green Street Policy
Category 3.
Category4.
The project will involve 5 or more dwelling units or is at a commercial or industrial site. It
will disturb more than 500 square feet of soil
The project falls under the Commercial/Industrial LID Categorv.
The project is subject to the provision of the Municipal Separate Storm Sewer System
permit (MS4) issued by the California Regional Water Quality Control Board. These
projects typically include (but are not limited to): new industrial parks 10,000 square feet
or more; new commercial malls 10,000 square feet or more; Retail gasoline outlets 5,000
square feet or more; new restaurants 5,000 square feet or more; new parking lots 5,000
square feet or more; or the creation or addition or replacement of 5,000 square feet or
more of impervious surfaces of existing projects meeting the Regional Board's
applicability criteria.
The project is beyond the scope of this manual and is subject to the requirements as
outlined in the /1154 Permit.
Under the MS4 permit, implementation of LID Standards for projects which will "result in the creation or
addition or replacement of 500 square feet or more of impervious surface area" is optionaL However,
the majority of the projects in Temple City are smaller projects, and requiring LID standards on those
projects will extend the benefit of LID. The criteria developed by staff are founded on the consideration
that LID implementation would not result in an unnecessary burden on the homeowner and low
maintenance will be required. The approval of the LID design for those smaller projects will be at the
discretion of staff and through the Site Plan Review process.
In proposing the adoption of LID for smaller projects, staff recommends two tiers and implementations:
projects of four or fewer units and projects of five or more units. For projects of four or fewer units, staff
proposes that at least two LID treatments be incorporated as part of the site improvement (as detailed
in Section 1.3 of the proposed Temple City Technical LID Guidance Manual (Attachment C)). For projects
of five or more units, staff proposes that one or more LID standards be required along with calculations
for adequate sizing. A template for calculation of LID sizing is provided in Section 3.1 of the Temple City
LID Technical Guidance ManuaL
Projects which automatically fall into the MS4 Permit applicable development/redevelopment
categories and/or identified as applicable categories in the proposed code amendments will be
required to follow the criteria and conditions contained in the proposed Low Impact Development
standards and/or Green Streets policy. The City's Low Impact Development Manual and Green Street
Manual are created as a technical guidance for implementations.
Green Streets Policy
The MS4 Permit does not strktly def1ne a green streets polky, however it does include a reference to
the USEPA Managing Wet Weather with Green Infrastructure: Green Streets guidance document The
reference is provided as follows:
"Street and road construction of 10,000 square feet or more of impervious surface area shall follow
US EPA guidance regarding Managing Wet Weather with Green Infrastructure: Green Streets (December
Page 3
October 17, 2013, Planning Commission Meeting
Staff Report-Item No.7 B
File No.: LID standards and Green Street Policy
2008 EPA-833-F-08-009) to the maximum extent practicable. Street and road construction applies to
standalone streets, roads, highways, and freeway projects, and also applies to streets within larger
projects."
RECOMMENDATION:
Staff recommends that the Planning Commission adopt Resolution No. 13-2382 recommending the City
Council approve the proposed code amendment, as provided in the attached Draft Ordinance No. 13-
979 (Attachment "B").
The proposed code amendment is Categorically Exempt from the California Environmental Quality Act
(CEQA) per Section 15061(b)(3) and Section 15308 of the CEQA Guidelines.
ATTACHMENTS
A. Draft PC Resolution No. 13-2382
B. Draft Ordinance 13-979
C. City of Temple City Low Impact Development for Small Sites Technical Guidance Manual
D. City of Temple City Green Streets Manual
Page 4
RESOLUTION NO. 13-2382 PC
A RESOLUTION OF THE PLANNING COMMISSION OF
THE CITY OF TEMPLE CITY RECOMMENDING THAT THE
CITY COUNCIL OF THE CITY OF TEMPLE CITY
APPROVE A MUNICIPAL CODE AMENDMENT TO
ESTABLISH LOW IMPACT DEVELOPMENT (LID)
STANDARDS AND A GREEN STREETS POLICY
The Planning Commission of the City of Temple City does hereby resolve:
SECTION 1. The Planning Commission has considered all of the evidence submitted
into the administrative record which includes, but is not limited to:
1. Staff reports were prepared by the Community Development Department.
2. Staff presentation at the public hearing held on October 17, 2013 before the
Planning Commission.
3. The City of Temple City Zoning Code, General Plan, and all other applicable
regulations and codes.
4. Public comments, both written and oral, received and/or submitted at or prior to
the public hearing, supporting and/or opposing the applicant's request.
5. Testimony and/or comments from the applicant and its representatives submitted
to the City in both written and oral form at or prior to the public hearing.
6. All related documents received and/or submitted at or prior to the public hearing.
SECTION 2. Based on the foregoing evidence, the Planning Commission finds that:
1. Notice of the October 17, 2013, Planning Commission public hearing was posted
at the Civic Center.
2. Notice of the Planning Commission public hearing was put in the newspaper
least ten (1 0) days prior to the hearing.
3. Notice of Planning Commission public hearing included the notice requirements
set forth in Government Code Section 65009 (b)(2).
SECTION 3. Based upon information presented in Staff Report dated October 17,
2013, and based upon a Public Hearing on October 17, 2013 to consider an
Resolution No. 13-2382 PC
Municipal Code Amendment-Low Impact Development
Page 2 of 3
amendment to the Municipal Code, the Planning Commission makes the following
findings:
1. 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;
2. 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;
3. 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;
4. Order No. R4-2012-0175 contains requirements for municipalities to establish an
LID Ordinance and Green Streets Policy in order to participate in a Watershed
Management Program and/or Enhanced Watershed Management Program;
5. The Regional Board has adopted Total Maximum Daily Loads (TMDLs) for
pollutants which are numerical limits that must be achieved effectively through
LID and Green Streets Policy implementation;
6. 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;
7. 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;
8. 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;
9. It is 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 as defined under
"Applicability";
10. The adoption of the code amendment will not unreasonably restrict the
developments and development rights; and
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Municipal Code Amendment-Low Impact Development
Page 3 of 3
11. The code amendment will not result in any significant effects upon the
environment, and is exempt per Section 15061 (b)(3) and Section 15308 of CEQA
Guidelines.
SECTION 4. The Planning Commission recommends that the City Council adopt
Ordinance No. 13-979 to amend Temple City Municipal Code by adding Low Impact
Development (LID) Standards and Green Streets Policy (as provided fully in Attachment
"B"), to Article E (Site Plan Review and Congestion Management) of Chapter 1 (Zoning
Code) ofTitle 9 (Zoning Regulations).
SECTION 5. The secretary shall certify to the adoption of this Resolution
Chairman
I hereby certify that the foregoing Resolution was duly adopted by the Planning
Commission of the City of Temple City at a regular meeting held on the 1 ih of October,
2013 by the following vote:
AYES:
NOES:
ABSTAIN:
ABSENT:
Commissioner-Curran, O'Leary, Cordes
Commissioner -
Commissioner-Leung, Horton
Commissioner-
Secretary