HomeMy WebLinkAboutMS 07-11; 3053 OCEAN STREET; URBAN STORM WATER MITIGATION PLAN FOR 3053 OCEAN STREET; 2008-05-14CONSTRUCTION TESTING & ENGINEERING, INC.
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Urban Storm Water Mitigation Plan
For
3053 Ocean Street
Carlsbad, California 92008
Project:
3053 OCEAN STREET RECE WED
CARLSBAD, CA MAY 202008
- ENGINEERING
DEPARTMENT
Prepared For:
3053 Ocean Street, LLC
513 Ocean Bluff Way
Encinitas, California 92024
9.OSS,0
Prepared By:
Construction Testing & Engineering, Inc. .66
1441 Montiel Road, Suite 115 E 9/30/08
Carlsbad, CA 92026
CTE Job No. 15-0072C May 14, 2008
GEOTECHNICAL I ENVIRONMENTAL I CONSTRUCTION INSPECTION AND TESTING I CIVIL ENGINEERING I SURVEYING
TABLE OF CONTENTS
Section
1.0 Vicinity Map............................................................................................................1
1.1 Project Location...................................................................................................1
2.0 Project Description ..................................................................................................1
2.1 Narrative of Project Activities.............................................................................1
3.0 Pollutants and Conditions of Concern.....................................................................2
3.1 Watershed...........................................................................................................
3.2 Impaired Waters & Impacts to Hydrologic Regime............................................2
3.3 Potential Downstream Erosion............................................................................3
3.4 Project Prioritization............................................................................................3
3.5 Project categorization..........................................................................................3
3.6 Pollutants of Concern ..........................................................................................3
4.0 Project BMPs ................................................................................................................. 4
4.1 Proposed BMP Selection.....................................................................................4
4.2 Site Design BMPs................................................................................................4
4.3 Source Control BMPs..........................................................................................5
4.4 BMPs Applicable to Individual Priority Project Categories................................6
4.5 Structural Treatment BMPs.................................................................................6
5.0 Maintenance Conditions..........................................................................................7
5.1 Owner ..................................................................................................................7
5.2 Maintenance Expenses.........................................................................................7
5.3 Responsible Party for Maintenance.....................................................................7
5.4 BMP Inspection & Maintenance .........................................................................7
5.5 Maintenance Items................................................................................................7
5.6 Inspection/Cleaning/Replacement Log................................................................8
ATTACHMENTS
ATTACHMENT 1 - Site Location and Site Plans
ATTACHMENT 2 - Standard Urban Storm Water Mitigation Tables
ATTACHMENT 3 - Standard Urban Storm Water Mitigation Plans (SUSMP) Checklist
for New Development
ATTACHMENT 4— Source Control and Treatment Control Fact Sheets
ATTACHMENT 5 - Inspection/Cleaning/Replacement Log
ATTACHMENT 6— Various Hydrology Documents
Urban Storm Water Mitigation Plan Page 1
3053 Ocean Street
May 14, 2008 CTE Job No. 15-0072C
1.0 Vicinity Map
1.1 Project Location
The project site is bordered to the north by an existing residence and to the south by an
existing residence. It is bordered to the east by Ocean Street and to the west by Pacific
Ocean. The project site is located between Carlsbad Village Drive and Oak Avenue and
the APN is 203-251-06. See Attachment 1 for location.
2.0 Project Description
2.1 Narrative of Project Activities
This report fulfills the City of Carlsbad's requirements for a Water Quality Technical
Report to address stormwater and water quality issues related to the 3053 Ocean project.
Within the project boundary is a single story residence which is to be demolished and
replaced with a three unit residential building. The site has a moderate to steep slope
from Ocean Street in the east toward the Pacific Ocean in the west and the new residence
design will incorporate the use of retaining walls and pile foundations to support the patio
and part of the new building to be put in place. In addition, Site improvements including
utilities and drainage structures shall also be constructed. Other on site development will
consist of utilities, drainage structures, landscaping, pavement and flatwork.
The proposed project can be constructed in compliance with the City of Carlsbad's
Stormwater Standards. This analysis .provides for post-construction stormwater
protection and ensures that the proposed BMPs are effective, with proper maintenance
and long-term fiscal responsibility.
Urban Storm Water Mitigation Plan Page 2
3053 Ocean Street
May 14, 2008 CTE Job No. 15-0072C
3.0 Pollutants and Conditions of Concern
3.1 Watershed
The proposed project is located within San Diego County, which encompasses an area of
over 4,000 square miles in the southwest corner of California. The County is bounded on
the north by Orange and Riverside Counties, on the east by Imperial County, on the south
by Mexico, and on the west by the Pacific Ocean. The northwest to southeast trending
Peninsula Range, the most prominent topographic feature in the region, divides the
County into the San Diego and Colorado hydrologic regions. The Peninsular Range
includes the Santa Ma, Ague Tibia, Palomar, Hot Springs, Aguanga, Volcan, Cuyamaca,
and Laguna Mountain systems and reaches a maximum elevation of over 6,500 feet
MSL. The climate in coastal San Diego County is generally mild, with temperatures
averaging about 65 degrees Fahrenheit and annual rainfall totaling 10 to 14 inches.
Proceeding inland from the coast, diurnal and seasonal temperatures fluctuate to a greater
degree and annual rainfall amounts typically increase. The foothills west of the
Peninsular Range average 16 to 20 inches of annual rainfall and the western slope of the
Peninsular Range receives as much as 45 inches of annual precipitation. The region has a
distinct rainy season, with the vast majority of precipitation occurring during the period
of October to April. There are a total of 11 hydrologic units (HUs) in the San Diego
Hydrology Region (SDFIR), encompassing a land area of nearly 3,000 square miles.
Eight major stream systems originate on the western slope of the Peninsular Range and
discharge into the Pacific Ocean. From north to south these streams are the San Juan
Creek, and the Santa Margarita, San Luis Rey, San Dieguito, San Diego, Sweetwater,
Otay,. and Tijuana Rivers.
The proposed project site is located in the Carlsbad Hydrologic Unit, within the Buena
Vista Creek Hydrologic Area, and the El Salto Hydrologic Subarea (904.21), which falls
within the San Diego Hydrologic Unit.
3.2 Impaired Waters & Impacts to Hydrologic Regime
According to the California 2002 303(d) list published by the San Diego Regional Water
Quality control Board, the Pacific Ocean Shoreline, Buena Vista Creek and Buena Vista
Lagoon is listed as impaired on the CWA 303 (d) list. The impacts are bacteria
Indicators and nutrients (indicated as Low priority) and Sedimentation/siltation (indicated
as Medium priority). These are all Point and nonpoint source potential sources.
Constituents of concern are coliform bacteria, nutrients, sediment, trace metals, and other
toxic constituents. Sources and activities that could cause these impacts are urban runoff,
and sewage spills.
Urban Storm Water Mitigation Plan Page 3
3053 Ocean Street
May 14, 2008 CTE Job No. 15-0072C
3.3 Potential Downstream Erosion
A drainage study was conducted to determine the stormwater runoff from the project site
in pre- and post-development conditions for the 100 year storm. The results of the
drainage study are as follows:
TABLE 3: PRE-POST-DEVELOPMENT CRITERIA SUMMARY
Basin 'C Tc I Area Q Comments
EX 1 0.491 1.160 6.323 0.139 0.432
EX 2 0.468 1.150 6.323 0.140 0.414
PR 1 0.537 2.700 6.323 0.138 0.469
PR 2 0.533 2.700 6.323 0.142 0.478
3.4 Project Prioritization
Per the City of Carlsbad Storm Water Management Requirements and Local Standard
Urban Storm Water Mitigation Plan Appendix A the project is categorized as high
priority as the project discharges into sensitive water bodies.
3.5 Project categorization
Per Table 1 of the City of Carlsbad Storm Water Management Requirements and Local
Standard Urban Storm Water Mitigation Plan the project is attached three unit residential
development. The project does not fall into any other categorizations. Thus, the required
BMPs include Site Design, Source Control, and Treatment Control BMPs. See
Attachment 2.
3.6 Pollutants of Concern
Per Table 2 of the City of Carlsbad Standard Urban Storm Water Mitigation Plan the
pollutants of concern are thus:
Sediments
Nutrients
Trash & Debris
Oxygen Demanding Substances
Oil & Grease
Bacteria & Viruses
Urban Storm Water Mitigation Plan Page 4
3053 Ocean Street
May 14, 2008 CTE Job No. 15-0072C
4.0 Project BMPs
4.1 Proposed BMIP Selection
Attached residential developments are required to address site design BMPs, source
control BMPs and structural treatment BMPs, to protect water quality and reduce erosion
to the maximum extent (MEP). The permanent and construction stormwater BMP
practices were determined using the City of Carlsbad's "Stormwater BMP Requirements
Matrix", "SUSMP Applicability form", and the "Stormwater Urban Runoff Management
Prioritization Requirements Checklist".
4.2 Site Design BMPs
The project development shall incorporate BMPs to control peak stormwater runoff and
velocities and mitigate downstream erosion. Development of the project site will
increase the impervious area. This increase is minimized by applying the following
concepts:
Minimize impervious footprint.
Use of permeable surfaces such as pervious concrete for walkways, trails,
patios, and other low-traffic areas would decrease the area of impervious
surfaces by several percent. Decorative concrete and other impervious
surfaces used in landscaping shall not be incorporated in the project design.
Minimize Directly Connected Impervious Areas.
Rooftops and any impervious driveways, sidewalks, walkways, trails, and
patios will be designed to drain into adjacent landscaping prior to discharging
to the storm water conveyance system.
Maximize canopy interception and water conservation
Existing native trees and shrubs shall be preserved to the maximum extent
practicable. Additional native or drought tolerant trees and large shrubs shall
be planted in place of non-drought tolerant exotics.
Protect Slopes and Channels
Non-irrigated slopes shall be vegetated with native or drought tolerant
vegetation. Stormwater runoff shall be directed to gravel lined swales where
it will be discharged into the existing drainage system.
Urban Storm Water Mitigation Plan Page 5
3053 Ocean Street
May 14, 2008 CTE Job No. 15-0072C
4.3 Source Control BMPs
Hazardous materials with the potential to contaminate urban runoff shall be placed in an
enclosure such as, but not limited to, a cabinet, shed, or similar structure that prevents
contact with rain, runoff or spillage to the storm water conveyance system; and is
protected by secondary containment structures such as berms, dikes, or curbs. The
storage area shall be paved and sufficiently impervious to contain leak and spills, and
have a roof or awning to minimize direct precipitation within the secondary containment
area.
Stormwater conveyance systems, including the concrete gutters and storm drain inlets
shall be labeled with appropriate stenciling and signage containing prohibitive language
(e.g., "No Dumping-I Live Downstream").
An informational package will be produced and disseminated to new tenants to educate
them on the many ways they can help keep our waters clean.
Design Trash Storage Areas to Reduce Pollution Introduction
1. Trash storage are will be:
Paved with impervious surface, screened and graded not to
allow run on from adjacent: This BMP will be used on this
project.
Contain lids on all trash containers: This BMP will be used
on this project.
Contain a roof or awning: This BMP will be used on this
project.
Use Efficient Irrigation Systems & Landscape Design
2. Employ Rain Shutoff Devices, flow reducers and shutoff valves. It
is anticipated that a combination of these devices will be used on the
projects landscaping. See landscaping plans.
3. Design irrigation systems to each landscape areas needs: This BMP
will be used on this project as needed. See landscaping plans.
4. Other methods that are comparable and equally effective: This
project uses the least amount of landscaping necessary.
Provide Storm Water Conveyance System Stenciling and Signage
5. Provide concrete stamping for all storm drain inlets: This BMP will
be employed on this project as needed.
6. Post signs and prohibitive language which prohibit illegal dumping
at public access points along channel and creeks.
Urban Storm Water Mitigation Plan Page 6
3053 Ocean Street
May 14, 2008 CTE Job No. 15-0072C
4.4 BMPs Applicable to Individual Priority Project Categories
Surface Parking Areas
Incorporate landscape areas into the drainage design: Because the
parking area has very little landscaping the listed BMP is not
applicable to this project.
Pave overflow parking with permeable payers: There is no overflow
parking on this job therefore this BMP is not applicable.
Education material regarding post construction BMPs may be obtained at the UC Davis
Website at: (http://www.cabmphandbooks.com).
4.5 Structural Treatment BMPs
The major sources of pollutants have been identified as residue from roofs, and nutrients
associated with irrigation and landscaping activities. It is unknown as to the exact
quantity of pollutants that will enter the stormwater system.
Graded hillside shall be landscaped with deep-rooted, drought tolerant plant species to
control erosion. Temporary or permanent irrigation may be necessary
Cistern and rain barrels will be implemented for the roof drain system and then will flow
into the proposed riprap at the southern and northern portions of the project.. It is
anticipated that stormwater from the roofs will not generate any bacterial pollutants.
Basis of Selection
Rain barrels are the most appropriate for the project as other bmps would not be as
effective. Biofilters and vegetative strips is not appropriate as the slopes of the site
exceed 2.5%.
Design Criteria
Design criteria will be based on the rain barrel manufacturer's specifications.
Urban Storm Water Mitigation Plan Page 7
3053 Ocean Street
May 14, 2008 CTE Job No. 15-0072C
5.0 Maintenance Conditions
5.1 Owner
3053 Ocean Street, LLC
513 Ocean Bluff Way
Encinitas, California 92024
The owner shall be responsible for all future maintenance, maintenance costs, activities
and inspections.
5.2 Maintenance Expenses
Maintenance expenses shall vary depending on brand and model installed. Annual costs
for maintenance shall be determined at a later date.
5.3 Responsible Party for Maintenance
It is expected that maintenance and inspection shall be perfonned by the owner. The
owner shall either have trained personnel perform the work or subcontract out for
experienced personnel.
5.4 BMP Inspection & Maintenance
All Permanent Post construction BMPs shall be maintained on a regular basis by
personnel working for the responsible party listed in section 5.1. If BMPs are not
inspected and maintained on a regular basis they will become ineffective in there
intended purpose.
Inspections shall be performed on a regular basis but at a minimum of monthly during the
dry season and weekly during the rainy season. Cleaning should be performed on a
regular basis to ensure system is not clogged by leaves or other debris. If different
structural treatment BMPs are used maintenance and cleaning should be performed per
the manufacturer's specifications.
5.5 Maintenance Items
ITEM BMP CLEANING REPLACEMENT
Rain Barrel As-Needed N/A
Riprap As-Needed N/A
Urban Storm Water Mitigation Plan Page 8
3053 Ocean Street
May 14, 2008 CTE Job No. 15-0072C
5.6 Inspection/Cleaning/Replacement Log
A log should be kept of all inspections and shall be filled out within Attachment 5. The
log should include the name of the person inspecting, date inspected and any pertinent
information noted during inspection.
An inspection, cleaning and replacement log should be kept for the sites structural
treatment BMPs. Records should be kept for five years.
ATTACHMENTS
ATTACHMENT 1
SITE LOCATION AND SITE PLANS
ATTACHMENT 2
STANDARD URBAN STORM WATER
MITIGATION PLAN TABLES
Storm Water Standards
4103/03
Table 1. Standard Developm
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>100,000 ft2
Automotive Repair Shop R R -
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Restaurants R R R R S
Hillside Development R R R - - - - - - - R S
>5,000ft2
Parking Lots R R - -
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Refer to Section 111.2.A.
Refer to Section 1112.13.
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Refer to Section 111.2.D.
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1.1
Storm Water Standards
4/03/03
Table 4. Structural Treatment Control BMP Selection Matrix.
Pollutant of Concern Treatment Control BMP Categories
Biofilters Detention Infiltration Wet Ponds or Drainage Filtration Hydrodynamic
Basins Basins(') Wetlands Inserts Separator Systems(2)
Sediment M H H H L H M______
Nutrients L M M M L M L________
Heavy Metals M M M H L H L_______
Organic Compounds U U U U L M L
Trash & Debris L H U U M H M
Oxygen Demanding L M M M L M L
Substances
Bacteria U U H U L M L
Oil& Grease M M _U_ U L H L
Pesticides U U U_ - U L U L
(1) Including trenches and porous pavement.
(2) Also known as hydrodynamic devices and baffle boxes.
Low removal efficiency
Medium removal efficiency
H: High removal efficiency
U: Unknown removal efficiency
Sources: Guidance Specifying Management Measures for Sources of Nonpoint Pollution in Coastal Waters (1993), National
Stormwafer Best Management Practices Database (2001), and Guide for BMP Selection in Urban Developed Areas (2001).
ii. Restrictions on the Use of Infiltration Treatment BMPs
31. Treatment control BMPs that are designed to primarily function as infiltration
devices shall meet the following conditions (these conditions do not apply to
treatment BMPs which allow incidental infiltration and are not designed to primarily
function as infiltration devices, such as grassy swales, detention basins, vegetated
buffer strips, constructed wetlands, etc.): (1) urban runoff from commercial
developments shall undergo pretreatment to remove both physical and chemical
contaminants, such as sedimentation or filtration, prior to infiltration; (2) all dry
weather flows shall be diverted from infiltration devices except for those non-storm
water discharges authorized pursuant to 40 CFR 122.26(d)(2)(iv)(B)(1): diverted
stream flows, rising ground waters, uncontaminated ground water infiltration [as
defined at 40 CFR 35.2005(20)] to storm water conveyance systems,
uncontaminated pumped ground water, foundation drains, springs, water from
crawl space pumps, footing drains, air conditioning condensation, flow from
riparian habitats and wetlands, water line flushing, landscape irrigation, discharges
from potable water sources other than water main breaks, irrigation water,
individual residential car washing, and dechlorinated swimming pool discharges;
(3) pollution prevention and source control BMPs shall be implemented at a level
appropriate to protect groundwater quality at sites where infiltration structural
treatment BMPs are to be used; (4) the vertical distance from the base of any
infiltration structural treatment BMP to the seasonal high groundwater mark shall
be at least 10 feet. Where groundwater does not support beneficial uses, this
vertical distance criterion may be reduced, provided groundwater quality is
maintained; (5) the soil through which infiltration is to occur shall have physical and
21
ATTACHMENT 3
Standard Urban Storm Water Mitigation Plans
(SUSMP) Checklist
for New Development
Storm Water Standards
4/03/03
APPENDIX A
STORM WATER REQUIREMENTS APPLICABILITY CHECKLIST
Complete Sections 1 and 2 of the following checklist to determine your project's
permanent and construction storm water best management practices requirements.
This form must be completed and submitted with your permit application.
Section 1. Permanent Storm Water BMP Requirements:
If any answers to Part A are answered "Yes," your. project is subject to the. "Priority
Project Permanent Storm Water BMP Requirements," and "Standard Permanent Storm
-Water BMP Requirements". in Section III, "Permanent Storm Water BMP Selection
Procedure" in the Storm Water Standards manual.
If all answers to Part A are "No," and any answers to Part B are "Yes," your project is
only subject to the "Standard Permanent Storm Water BMP Requirements". If every
question in Part 'A and B is answered "No," your project is exempt from permanent
storm water requirements.
Part A: Determine Priority Proict Prmnnf Stnrm Wifr RMP Ranniramante.
Does the project meet the definition of one or more of the priority project
categories?* Yes N
Detached residential development of 10 or more units - Attached residential development of 10 or more units X... Commercial development greater than 100,000 square feet .
-
- Automotive repair shop
- Restaurant
- Steep hillside development greater than 5,000 square feet . -
Project discharging to receiving waters within Environmentally Sensitive Areas - Parking lots greater than or equal to 5,000 ft' or with at least 15 parking spaces, and
potentially exposed to urban runoff
Streets, roads, highways, and freeways which would create a new paved surface that is
5,000 square feet or greater
- * Refer to the definitions section in the Storm Water Standards for expanded definitions of the priority
project categories. . .
Limited Exclusion: Trenching and resurfacing work associated with utility projects are not considered
priority projects. Parking lots, buildings and other structures associated with utility projects are
priority projects if one or more of the criteria in Part A is met. If all answers to Part A are "No",
continue to Part B.
30
Storm Water Standards
4/03/03
Part B: Determine Standard Permanent Storm Water Requirements.
Does the project propose: Yes No
New impervious areas, such as rooftops, roads, parking lots, driveways, paths and
sidewalks? - -
New pervious landscape areas and irrigation systems?
- Permanent structures within 100 feet of any natural water body? X - Trash storage areas?
Liquid or solid material loading and unloading areas?
- x Vehicle or equipment fueling, washing, or maintenance areas?
- Require a General NPDES Permit for Storm Water Discharges Associated with
Industrial Activities (Except construction)?*
- Commercial or industrial waste handling or storage, excluding typical office or
household waste?
Any grading or ground disturbance during construction? _._x__ Any new storm drains, or alteration to existing storm drains? -
- *To find out if your project is required to obtain an individual General NPDES Permit for Storm Water
Discharges Associated with Industrial Activities, visit the State Water Resources Control Board web site
'it, www.swrcb.ca.gov/stormwtr/industrial.html
Section 2. Construction Storm Water BMP Requirements:
If the answer to question I of Part C is answered "Yes," your project is subject to
Section IV, "Construction Storm Water BMP Performance Standards," and must prepare
a Storm Water Pollution Prevention Plan (SWPPP). If the answer to question I is "No,"
but the answer to any of the remaining questions is "Yes," your project is subject to
Section IV, "Construction Storm Water BMP Performance Standards," and must prepare
a Water Pollution Control Plan (WPCP). If every question in Part C is answered "No,"
your project is exempt from any construction storm water BMP requirements. If any of
the answers to the questions in Part C are "Yes," complete the construction site
prioritization in Part D, below.
Part C: Determine Construction Phase Storm Water Requirements.
Would the project meet any of these criteria during construction? Yes No
Is the project subject to California's statewide General NPDES Permit for Storm Water
- - Discharges Associated With Construction Activities?
- - Does the project propose grading or soil disturbance? X - Would storm water or urban runoff have the potential to contact any portion of the
construction area, including washing and staging areas?
- Would the project use any construction materials that could negatively affect water
quality if discharged from the site (such as, paints, solvents, concrete, and
stucco)?
31
Storm Water Standards
4/03/03
Part D: Determine Construction Site Priority
In accordance with the Municipal Permit, each construction site with construction storm
water BMP requirements must be designated with a priority: high, medium or low.
This prioritization must be completed with this form, noted on the plans, and included in
the SWPPP or WPCP. Indicate the project's priority in one of the check boxes using the
criteria below, and existing and surrounding conditions of the project, the type of
activities necessary to complete the construction and any other extenuating
circumstances that may pose a threat to water quality. The City reserves the right to
adjust the priority of the projects both before and during construction. [Note:
The construction priority does NOT change construction BMP requirements that apply
to projects; all construction BMP requirements must be identified on a case-by-case
basis. The construction priority does affect the frequency of inspections that will be
conducted by City staff. See Section IV.1 for more details on construction BMP
requirements.]
A) High Priority
Projects where the site is 50 acres or more and grading will occur during the
rainy season
Projects 5 acres or more. 3) Projects 5 acres or more within or directly
adjacent to or discharging directly to a coastal lagoon or other receiving water
within an environmentally sensitive area
Projects, active or inactive, adjacent or tributary to sensitive water bodies
B) Medium Priority
Capital Improvement Projects where grading occurs, however a Storm Water
Pollution Prevention Plan (SWPPP) is not required under the State General
Construction Permit (i.e., water and sewer replacement projects, intersection
and street re-alignments, widening, comfort stations, etc.)
Permit projects in the public right-of-way where grading occurs, such as
installation of sidewalk, substantial retaining walls, curb and gutter for an
entire street frontage, etc. , however SWPPPs are not required.
Permit projects on private property where grading permits are required,
however, Notice Of Intents (NOls) and SWPPPs are not required.
U C) Low Priority
Capital Projects where minimal to no grading occurs, such as signal light and
loop installations, street light installations, etc.
Permit projects in the public right-of-way where minimal to no grading occurs,
such as pedestrian ramps, driveway additions, small retaining walls, etc.
Permit projects on private property where grading permits are not required,
such as small retaining walls, single-family homes, small tenant
improvements, etc.
tM
Site Design & Landscape Planning SD-10
Design Objectives
Ef Maxinize Infiltration
0 Provide Retention
Ef Slow Runoff
El Minimize Impervious Land
Coverage
Prohibit Dumping of Improper
Materials
Contain Pollutants
Collect and Convey
Description
Each project site possesses unique topographic, hydrologic, and vegetative features, some of
which are more suitable for development than others. Integrating and incorporating
appropriate landscape planning methodologies into the project design is the most effective
action that can be done to minimize surface and groundwater contamination from stormwater.
Approach
Landscape planning should couple consideration of land suitability for urban uses with
consideration of community goals and projected growth. Project plan designs should conserve
natural areas to the extent possible, maximize natural water storage and infiltration
opportunities, and protect slopes and channels.
Suitable Applications
Appropriate applications include residential, commercial and industrial areas planned for
development or redevelopment
Design Considerations
Design requirements for site design and landscapes planning
should conform to applicable standards and specifications of
agencies with jurisdiction and be consistent with applicable
General Plan and Local Area Plan policies.
4..fUItNjAS4UXM,%Aflit Q/tTr( .rI.Jhv.
January 2003 California Stormwater BMP Handbook 1 of 4
New Development and Redevelopment
www.cabmphandbooks.com
SD-10 Site Design & Landscape Planning
Designing New Installations
Begin the development of a plan for the landscape unit with attention to the following general principles:
i Formulate the plan on the basis of clearly articulated community goals. Carefully identify conflicts and choices between retaining and protecting desired resources and community growth.
Map and assess land suitability for urban uses. Include the following landscape features in
the assessment wooded land, open unwooded land, steep slopes, erosion-prone soils,
foundation suitability, soil suitability for waste disposal, aquifers, aquifer recharge areas, wetlands, floodplains, surface waters, agricultural lands, and various categories of urban land use. When appropriate, the assessment can highlight outstanding local or regional resources that the community determines should be protected (e.g., a scenic area,
recreational area, threatened species habitat farmland, fish run). Mapping and assessment should recognize not only these resources but also additional areas needed for their sustenance.
Project plan designs should conserve natural areas to the extent possible, maximize natural water storage and infiltration opportunities, and protect slopes and channels.
Conserve Natural Areas during Landscape Planning
If applicable, the following items are required and must be implemented in the site layout
during the subdivision design and approval process, consistent with applicable General Plan and Local Area Plan policies:
Cluster development on least-sensitive portions of a site while leaving the remaining land in
a natural undisturbed condition.
Limit clearing and grading of native vegetation at a site to the minimum amount needed to build lots, allow access, and provide fire protection.
Maximize trees and other vegetation at each site by planting additional vegetation, clustering tree areas, and promoting the use of native and/or drought tolerant plants.
Promote natural vegetation by using parking lot islands and other landscaped areas.
Preserve riparian areas and wetlands.
Maximize Natural Water Storage and Infiltration Opportunities Within the Landscape Unit
Promote the conservation of forest cover. Building on land that is already deforested affects basin hydrology to a lesser extent than converting forested land. Loss of forest cover reduces
interception storage, detention in the organic forest floor layer, and water losses by evapotranspiration, resulting in large peak runoff increases and either their negative effects or the expense of countering them with structural solutions.
Maintain natural storage reservoirs and drainage corridors, including depressions, areas of permeable soils, swales, and intermittent streams. Develop and implement policies and
2 014 Callfbrnla Stormwater BMP Handbook January 2003 New Development and Redevelopment
www.cabmphandbooks.com
Site Design & Landscape Planning SD-10
regulations to discourage the clearing, filling, and charmelization of these features. Utilize
them in drainage networks in preference to pipes, culverts, and engineered ditches.
Evaluating infiltration opportunities by referring to the stormwater management manual for
the jurisdiction and pay particular attention to the selection criteria for avoiding
groundwater contamination, poor soils, and hydrogeological conditions that cause these
facilities to fail. If necessary, locate developments with large amounts of impervious
surfaces or a potential to produce relatively contaminated runoff away from groundwater
recharge areas.
Protection of Slopes and Channels during Landscape Design
Convey runoff safely from the tops of slopes.
Avoid disturbing steep or unstable slopes.
Avoid disturbing natural channels.
Stabilize disturbed slopes as quickly as possible.
Vegetate slopes with native or drought tolerant vegetation.
Control and treat flows in landscaping and/or other controls prior to reaching existing
natural drainage systems.
Stabilize temporary and permanent channel crossings as quickly as possible, and ensure that
increases in run-off velocity and frequency caused by the project do not erode the channel.
Install energy dissipaters, such as riprap, at the outlets of new storm drains, culverts,
conduits, or channels that enter unlined channels in accordance with applicable
specifications to minimize erosion. Energy dissipaters shall be installed in such a way as to
minimize impacts to receiving waters.
Line on-site conveyance channels where appropriate, to reduce erosion caused by increased
flow velocity due to increases in tributary impervious area. The first choice for linings
should be grass or some other vegetative surface, since these materials not only reduce
runoff velocities, but also provide water quality benefits from filtration and infiltration, if
velocities in the channel are high enough to erode grass or other vegetative linings, nprap,
concrete, soil cement, or geo-grid stabilization are other alternatives.
Consider other design principles that are comparable and equally effective.
Redeveloping Existing Installations
Various jurisdictional stormwater management and mitigation plans (SUSMP, WQMP, etc.)
define "redevelopment' in terms of amounts of additional impervious area, increases in gross
floor area and/or exterior construction, and land disturbing activities with structural or
impervious surfaces. The definition of" redevelopment' must be consulted to determine
whether or not the requirements for new development apply to areas intended for
redevelopment. If the definition applies, the steps outlined under "designing new installations"
above should be followed.
January 2003 California StormwaterBMPHandbook 3 of 4
New Development and Redevelopment
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SD-10 Site Design & Landscape Planning
Redevelopment may present significant opportunity to add features which had not previously
been implemented. Examples include incorporation of depressions, areas of permeable soils,
and swales in newly redeveloped areas. While some site constraints may exist due to the status
of already existing infrastructure, opportunities should not be missed to maximize infiltration,
slow runoff, reduce impervious areas, disconnect directly connected impervious areas.
Other Resources
A Manual for the Standard Urban Stormwater Mitigation Plan (SUSMP), Los Angeles County
Department of Public Works, May 2002.
Stormwater Management Manual for Western Washington, Washington State Department of
Ecology, August 2001.
Model Standard Urban Storm Water Mitigation Plan (SUSMP) for San Diego County, Port of
San Diego, and Cities in San Diego County, February 14, 2002.
Model Water Quality Management Plan (WQMP) for County of Orange, Orange County Flood
Control Disirict, and the Incorporated Cities of Orange County, Draft February 2003.
Ventura Countywide Technical Guidance Manual for Stormwater Quality Control Measures,
July 2002.
4 of 4 Calllbrnla Stormwater BMP Handbook January 2003
New Development and Redevelopment
www.cabmphandbooks.com
Roof Runoff ConVols SD1 1
Design Objectives
Ef Ma,drrize lnllltration
Provide Retention
Ef Slow Runoff
Minimize Impervious Land
Coverage
Prohibit Dumping of Improper
Materials
Ef Contain Pollutants
Collect and Convey
Rain Garden
Description
Various roof runoff controls are available to address stormwater
that drains off rooftops. The objective is to reduce the total volume and rate of runoff from
individual iota, and retain the pollutants on site that may be picked up from roofing materials
and atmospheric deposition. Roof runoff controls consist of directing the roof runoff away from
paved areas and mitigating flow to the storm drain system through one of several general
approaches: cisterns or rain barrels; dry wells or infiltration trenches; pop-up emitters, and
foundation planting. The first three approaches require the roof runoff to be contained in a
gutter and downspout system. Foundation planting provides a vegetated strip under the drip
line of the roof.
Approach
Design of individual iota for single-family homes as well as lots for higher density residential and
commercial structures should consider site design provisions for containing and infiltrating roof
runoff or directing roof runoff to vegetative swales or buffer areas. Retained water can be reused
for watering gardens, lawns, and trees Benefits to the environment include reduced demand for
potable water used for irrigation, improved stormwater quality, increased groundwater
recharge, decreased runoff volume and peak flows, and decreased flooding potential.
Suitable Applications
Appropriate applications include residential, commercial and industrial areas planned for
development or redevelopment.
Design Considerations
Designing New Installations
Cisterns or Rain Barrels
One method of addressing roof runoff is to direct roof downspouts
to cisterns or rain barrels. A cistern is an above ground storage
vessel with either a manually operated valve or a permanently
open outlet. Roof runoff is temporarily stored and then released
for irrigation or infiltration between storms. The number of rain
January 2003 Califa-nla Stormwater BMP Handbook -- 1 of 3
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SD-11 Roof Runoff Controls
barrels needed is a function of the rooftop area. Some low impact developers recommend that
every house have at least 2 rain barrels, with a minimum storage capacity of 1000 liters. Roof
barrels serve several purposes including mitigating the first flush from the roof which has a high volume, amount of contaminants, and thermal load. Several types of rain barrels are
commercially available. Consideration must be given to selecting rain barrels that are vector proof and childproof. In addition, some barrels are designed with a bypass valve that filters out grit and other contaminants and routes overflow to a soak-away pit or rain garden.
If the cistern has an operable valve, the valve can be dosed to store stormwater for irrigation or
infiltration between storms. This system requires continual monitoring by the resident or grounds crews, but provides greater flexibility in water storage and metering. If a cistern is
provided with an operable valve and water is stored inside for long periods, the cistern must be covered to prevent mosquitoes from breeding.
A cistern system with a permanently open outlet can also provide for metering stormwater
runoff. if the cistern outlet is significantly smaller than the size of the downspout inlet (say ¼ to ½ inch diameter), runoff will build up inside the cistern during storms, and will empty out
slowly after peak intensities subside. This is a feasible way to mitigate the peak flow increases caused by rooftop impervious land coverage, especially for the frequent, small storms.
Dry wells andlnfiltration Trenches
Roof downspouts can be directed to dry wells or infiltration trenches. A dry well is constructed by excavating a hole in the ground and filling it with an open graded aggregate, and allowing the water to fill the dry well and infiltrate after the storm event. An underground connection from
the downspout conveys water into the dry well, allowing it to be stored in the voids. To minimize sedimentation from lateral soil movement, the sides and top of the stone storage
matrix can be wrapped in a permeable filter fabric, though the bottom may remain open. A
perforated observation pipe can be inserted vertically into the dry well to allow for inspection and maintenance.
In practice, dry wells receiving runoff from single roof downspouts have been successful over long periods because they contain very little sediment They must be sized according to the amount of rooftop runoff received, but are typically 4 to 5 feet square, and 2 to 3 feet deep, with a minimum of 1-foot soil cover over the top (maximum depth of 10 feet).
To protect the foundation, thy wells must be set away from the building at least 10 feet. They must be installed in solids that accommodate infiltration. In poorly drained soils, dry wells have very limited feasibility.
Infiltration trenches function in a similar manner and would be particularly effective for larger roof areas. An infiltration trench is along, narrow, rock-filled trench with no outlet that receives
stormwater runoff. These are described under Treatment Controls.
Pop-up Drainage Emitter
Roof downspouts can be directed to an underground pipe that daylights some distance from the
building foundation, releasing the roof runoff through a pop-up emitter. Similar to a pop-up irrigation head, the emitter only opens when there is flow from the roof. The emitter remains
flush to the ground during thy periods, for ease of lawn or landscape maintenance.
2 of 3 California Stormwater BMP Handbook January 2003
New Development and Redevelopment
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Roof Runoff Control s SD-l1
Foundation Planting
Landscape planting can be provided around the base to allow increased opportunities for
stormwater infiltration and protect the soil from erosion caused by concentrated sheet flow
coming off the roof. Foundation plantings can reduce the physical impact of water on the soil
and provide a subsurface matrix of roots that encourage infiltration. These plantings must be
sturdy enough to tolerate the heavy runoff sheet flows, and periodic soil saturation.
Redeveloping Existing Installations
Various jurisdictional stormwater management and mitigation plans (SUSMP, WQMP, etc.)
define "redevelopment' in terms of amounts of additional impervious area, increases in gross
floor area and/or exterior construction, and land disturbing activities with structural or
impervious surfaces. The definition of" redevelopment' must be consulted to determine
whether or not the requirements for new development apply to areas intended for
redevelopment. If the definition applies, the steps outlined under "designing new installations"
above should be followed.
Supplemental Information
Examples
City of Ottawa's Water Links Surface —Water Quality Protection Program
City of Toronto Downspout Disconnection Program
City of Boston, MA, Rain Barrel Demonstration Program
Other Resources
Hager, Marty Catherine, Stormwater, "Low-Impact Development", January/February 2003. www.stormh2o.com
Low Impact Urban Design Tools, Low Impact Development Design Center, Beltsville, MD.
www,lid-storxnwater.net
Start at the Source, Bay Area Stormwater Management Agencies Association, 1999 Edition
January 2003 California Stormwater BMP Handbook 3 of 3
New Development and Redevelopment
www.cabmphandbock.com
Efficient lrriqp~ioh,
______________
_
_
_
_
_
_
_
_
Design Objectives
J1 Maxirrze Infiltration
Provide Retention
Slow Runoff
Mini me Impervious Land
Coverage.
•. Prohibit Dumping of Improper
Materials
Contain Pollutants
Collect end Convey
NO
;**
. . • . .
. Description
Irrigation water provided to landscaped areas may result in excess irrigation water being •1
• • * conveyed into stormwater drainage systems. - ..
Approach
• . •. • .. • .
. Project plan designs for development and redevelopment should include application methods of
irrigation water that minimize runoff of excess irrigation water into the stormwater conveyance system. .
Suitable Applications . .• • • .
Appropriate applications include residential, commercial and industrial areas planned for development or redevelopment (Detached residential iiigle-fa±nily homes are typically excluded from this requirement.) .• •. . .
Design Considerations ... ..: •
. . • Designing New Installations . . . •
The following methàds to reduce excessive irrigation runoff should be considered, and incorporated and iinplemented where determined applicable and feasible by the Perniittee:
Employ rain-triggered shutoff devices to prevent irrigation after precipitation.
Design irrigation systems to each landscape area's specific water requirements
Include design featuring flow reducrs or shutoff valves
triggered by a pressure drop to control water loss in the event : of broken sprinkler heads or lines.
• • • .
.. . .
,•
*, .
Implement landscape plans consistent with Cointy àr City •
water coiiservation resolutions, which may include provision
• of water sensors, programmable irrigation times (for short
-. .
• cycles), etè.
. • • . •• •. A
. . . .
. . &_.Ui.%K1*l. . • • •
. 3au&y 2003. • • • • California Stormwater BMP Handbook • 1 of 2
• . New Development and Redevelopment . • .
• . . www.cabmphandbooks.com
SD12 Efficient Irrigation
Design timing and application methods of irrigation water to minimize the runoff of excess
irrigation water into the storm water drainage system.
Group plants with similar water requirements in order to reduce excess irrigation runoff and
promote surface filtration. Choose plants with low irrigation requirements (for example,
native or drought tolerant species). Consider design features such as:
- Using mulches (such as wood chips or bar) in planter areas without ground coverto
minimize sediment in runoff
- Installing appropriate plant materials for the location, in accordance with amount of
sunlight and climate, and use native plant materials where possible and/or as
recommended by the landscape architect
- Leaving a vegetative barrier along the property boundary and interior watercourses, to
act as a pollutant filter, where appropriate and feasible
- Choosing plants that minimize or 'eliminate the use of fertilizer or pesticides to sustain
growth
Employ other comparable, equally effective methods to reduce irrigation water runoff.
Redeveloping Existing Installations
Various jurisdictional stormwater management and mitigation plans (SUSMP, WQMP, etc.)
define "redevelopment" in terms of amounts of additional impervious area, increases in gross
floor area and/or exterior construction, and land disturbing activities with structural or
impervious surfaces. The definition of" redevelopment" must be consulted to determine
whether or not the requirements for new development apply to areas intended for
redevelopment If the definition applies, the steps outlined under "designing new installations"
above should be followed.
Other Resources
A Manual for the Standard Urban Stormwater Mitigation Plan (SUSMP), Los Angeles County
Department of Public Works, May 2002.
Model Standard Urban Storm Water Mitigation Plan (SUSMP) for San Diego County, Port of
San Diego, and Cities in San Diego County, February 14, 2002.
Model Water Quality Management Plan (WQMP) for County of Orange, Orange County Flood
Control District; and the Incorporated Cities of Orange County, Draft February 2003.
Ventura Countywide Technical Guidance Manual for Stormwater Quality Control Measures,
July 2002.
2 of 2 CalIfornIa Stormwater BMP Handbook January 2003
New Development and Redevelopment
www.cabmphandbooks.com
Trash Storage Areas SD-32
Description
Trash storage areas are areas where a trash receptacle (s) are
located for use as a repository for solid wastes. Stormwater
runoff from areas where trash is stored or disposed of can be
polluted. In addition, loose trash and debris can be easily
transported by water or wind into nearby storm drain inlets,
channels, and/or creeks. Waste handling operations that may be
sources of stormwater pollution include dumpsters, litter control,
and waste piles.
Approach
This fact sheet contains details on the specific measures required
to prevent or reduce pollutants in stormwater runoff associated
with trash storage and handling. Preventative measures
including enclosures, containment structures, and impervious
pavements to mitigate spills, should be used to reduce the
likelihood of contamination.
Suitable Applications
Design Objectives
Maximize tnItration
Provide Retention
Stow Runoff
Minimize Impervious Land
Coverage
Prohibit Dumping of tnproper
Materials
Contain Pollutants
Collect and Convey
Appropriate applications include residential, commercial and industrial areas planned for
development or redevelopment (Detached residential single-family homes are typically
excluded from this requirement.)
Design Considerations
Design requirements for waste handling areas are governed by Building and Fire Codes, and by
current local agency ordinances and zoning requirements. The design criteria described in this
fact sheet are meant to enhance and be consistent with these code and ordinance requirements.
Hazardous waste should be handled in accordance with legal requirements established in Title
22, California Code of Regulation.
Wastes from commercial and industrial sites are typically hauled by either public or commercial
carriers that may have design or access requirements for waste storage areas. The design
criteria in this fact sheet are recommendations and are not intended to be in conflict with
requirements established by the waste hauler. The waste hauler should be contacted prior to the
design of your site trash collection areas. Conflicts or issues should be discussed with the local
agency.
Designing New Installations
Trash storage areas should be designed to consider the following structural or treatment control
BMPs:
Design trash container areas so that drainage from adjoining
roofs and pavement is diverted around the area(s) to avoid
run-on. This might include berining or grading the waste
handling area to prevent run-on of stormwater.
Make sure trash container areas are screened or walled to
prevent off-site transport of trash. A
cALv.-_wWtsroAmwA rIi
January 2003 California Stormwater BMP Handbook I of 2
New Development and Redevelopment
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SD-32 Trash Storage Areas
a Use lined bins or dumpsters to reduce leaking of liquid waste.
a Provide roofs, awnings, or attached lids on all trash containers to minimize direct
precipitation and prevent rainfall from entering containers.
Pave trash storage areas with an impervious surface to mitigate spills.
Do not locate storm drains in immediate vicinity of the trash storage area.
a Post signs on all dumpsters informing users that hazardous materials are not to be disposed
of therein.
Redeveloping Existing Installations
Various jurisdictional stormwater management and mitigation plans (SUSMP, WQMP, etc.)
define "redevelopment" in terms of amounts of additional impervious area, increases in gross
floor area and/or exterior construction, and land disturbing activities with structural or
impervious surfaces. The definition of" redevelopment" must be consulted to determine
whether or not the requirements for new development apply to areas intended for
redevelopment If the definition applies, the steps outlined under "designing new installations"
above should be followed.
Additional Information
Maintenance Considerations
The integrity of structural elements that are subject to damage (i.e., screens, covers, and signs)
must be maintained by the owner/operator. Maintenance agreements between the local agency
and the owner/operator may be required. Some agencies will require maintenance deed
restrictions to be recorded of the property title. If required by the local agency, maintenance
agreements or deed restrictions must be executed by the owner/operator before improvement
plans are approved.
Other Resources
A Manual for the Standard Urban Stormwater Mitigation Plan (SUSMP), Los Angeles County
Department of Public Works, May 2002.
Model Standard Urban Storm Water Mitigation Plan (SUSMP) for San Diego County, Port of
San Diego, and Cities in San Diego County, February 14, 2002.
Model Water Quality Management Plan (WQMP) for County of Orange, Orange County Flood
Control District, and the Incorporated Cities of Orange County, Draft February 2003.
Ventura Countywide Technical Guidance Manual for Stormwater Quality Control Measures,
July 2002.
2 of 2 CalUbrnla Stormwater BMP Handbook January 2003
New Development and Redevelopment
www.cabmphandbooks.com
gi rgk/wecn
Fact Sheet 26. Cisterns & Rain Barrels
i uthw&rgyt M w,.,j fr
A cistern is an above ground storage vessel that is directly connected with the roof
downspout. Water is slowly released with either'a,, i'nanüally operated valve or a
permanently open outlet.
CHARACTERISTICS
Cisterns can be incorporated into the aesthetics of the building and garden.
Reduces peak runoff and allows sediment t settle.
Provides more inflltiàfion benefits than connectiig directly to storm drain.
APPLICATION L.
New and existing reside tial buildings
DESIGN'
Manually operated valve can be closed to store stormwater for irrigation use or
infiltration between storms.
.
Cisthrn must be covered to prevent mosquitoes from breeding.
Permanently open outlet must be sized appropriately.
Size cistern for water quality volume, provide overflow for larger storms.
f • For safety reasons provide secure cover or ( 4" top opening if holding more than
6" depth of water.
Provide screen on gutter and intake of outlet pipe to minimize clogging by leaves
and other debris.
MAINTENANCE
System requires regular monitoring and cleaning.
. Ensure system is not clogged by leaves or other debris.
Public Review Draft -87 - 7/20/2007
Public Review Draft -88 - 7/20/2007
ATTACHMENT 5
Inspection/Cleaning/Replacement Log
Inspection/Cleaning/Replacement Log Page
3053 Ocean Street, LLC
513 Ocean Bluff Way
Encinitas, California 92024
ITEM ACTIVITY INTERVAL DATE DUE DATE BY NOTES
PERF. (Init)
ATTACHMENT 6
Various Hydrology Documents
H - -
0,60
RIVERSIDE COUNTY
N
'
7
e Precipitation
~?aiiifafi in Inches
DRA FT
62 7/01
IA
0 water quality is based on volume:
Reference: WEF Manual of Practice No. 23/ ASCE Manual of Practice No. 87, (1998)
Formulas
P0 = [A*C]*P6 Formula 5.2
C = 0.858i - 0.78i2 + 0.774i + 0.04
Vstorage P*Area
Data
i = 0.30 (4.3 •DU/A - San Diego Hydrology Manual 2003)
A = 1.2999
P6 = 0.60 inch (85th Percentile Map)
Area = 0.10 acres
C = 0.858i - 0.78i2 + 0.774i + 0.04
=0.23
P0 =[A*C]*P6
= [1.2999*0.23]*0.60
= 0.18"/12 = 0.015 ac-fl/ac
Increase by 10% for silt storage
P0 = 1.1(0.015) = 0.016 ac -ft/ac
Vstorage = po*Area
=0.016*0.10
= 0.002(43560)
= 70.0 cf