HomeMy WebLinkAbout3811; El Camino Real Widening Project Water Quailty; El Camino Real Widening Project Water Quailty; 2007-08-03CITY OF CARLSBAD
WATER QUALITY TECHNICAL REPORT
EL CAMINO REAL WIDENING PROJECT
Location: El Camino Real - From Tamarack Ave. to Chestnut Rd.
Prepared: January 12, 2007
Revised: August 03, 2007
Prepared for:
City of Carlsbad
1635 Faraday Avenue
Carlsbad, CA 92008
BUREAU
VERITAS
Prepared by:
Bureau Veritas North America Inc.
11590 West Bernardo Court, Suite 100
San Diego, CA 92127-1624
This Water Quality Technical Report has been prepared under the direction of Sharon L.
Humphreys, a Registered Civil Engineer in the State of California. The Registered Civil
Engineer attests to the technical information contained herein and the engineering data upon
which recommendations, conclusions, and decisions are based.
DATE
SHARON L. HUMPHREYS
REGISTERED CIVIL ENGINEER
El Camino Real Widening Improvement Project
City of Carlsbad - Water Quality Technical Report
Final Report 8/3/2007
TABLE OF CONTENTS
SECTION PAGE
* TABLE OF CONTENTS I
APPENDICES ii
m LIST OF TABLES ii
ABBREVIATIONS iii
ACRONYMS iii
INTRODUCTION 4
" 1.0 PROJECT DESCRIPTION 7
1.1 TOPOGRAPHY AND LAND USE 7
^ 1.2 HYDROLOGIC UNIT CONTRIBUTION 7
«, 2.0 WATER QUALITY ENVIRONMENT 8
2.1 BENEFICIAL USES 8
2.1.1 INLAND SURFACE WATERS 9
m 2.1.2 COASTAL WATERS 10
2.1.3 GROUNDWATER 10
2.2 303(D) STATUS 10
3.0 CHARACTERIZATION OF PROJECT RUNOFF 11
m 3.1 EXISTING AND POST-CONSTRUCTION DRAINAGE 11
^ 3.2 POST-CONSTRUCTION EXPECTED DISCHARGES 11
4.0 MITIGATION MEASURES TO PROTECT WATER QUALITY 14
^ 4.1 CONSTRUCTION BMPS 14
* 4.2 POST-CONSTRUCTION BMPS 16
4.2.1 SITE DESIGN BMPs 17
4.2.2 SOURCE CONTROL BMPs 17
•* 4.2.3 TREATMENT BMPs 18
4.3 OPERATION AND MAINTENANCE PLAN 21
5.0 FISCAL RESOURCES 23
6.0 FISCAL RESOURCES 23
mm
m 7.0 CONCLUSIONS 23
8.0 REFERENCES 24
El Camino Real Widening Improvement Project
City of Carlsbad - Water Quality Technical Report
Final Report 8/3/2007
APPENDICES
APPENDIX A
APPENDIX B
APPENDIX C
APPENDIX D
VICINITY AND SITE MAP
El CAMINO REAL DRAINAGE EXHIBIT
WATER QUALITY TREATMENT CALCULATIONS
BMP FACT SHEETS
LIST OF TABLES
Table 1. SUSMP Applicability Form 4
Table 2. Hydrologic Unit in Project Vicinity 7
Table 3. Project Contributions to Watershed 7
Table 4. Description of Beneficial Uses 8
Table 5. Beneficial Uses of Inland Surface Waters 9
Table 6. Beneficial Uses of Coastal Waters 10
Table 7. Beneficial Uses of Inland Ground Waters 10
Table 8. 303 (d) Water Bodies Listed with Constituents of Concern 10
Table 9. Post-Construction Flows 11
Table 10. Anticipated and Potential Pollutants Generated By Land Use Type 12
Table 11. General Pollutant Categories and Descriptions 12
Table 12. BMPs Applicable to Priority Projects 14
Table 13. Selected Construction Site BMPs 15
Table 14. BMP Categories and Descriptions 16
Table 15. Structural Treatment Control BMP Selection Matrix 19
Table 16. Native Planted Swale Lengths 20
Table 17. Permanent BMP Operation and Maintenance Requirements 22
El Camino Real Widening Improvement Project
City of Carlsbad - Water Quality Technical Report
Final Report 8/3/2007
ABBREVIATIONS
ft
gal
gpm
ha
in
I
m
mm
S
Feet
Gallon
Gallons per minute
Hectares
Inches
liter
Meters
Millimeters
Second
ACRONYMS
m
BMP Best Management Practice
Caltrans California Department of Transportation
CWA Clean Water Act
EPA United States Environmental Protection Agency
MS4 Municipal Separate Storm Sewer System
NOl Notice of Intent
NPDES National Pollutant Discharge Elimination System
RWQCB California Regional Water Quality Control Board
SWPPP Storm Water Pollution Prevention Plan
SWRCB California State Water Resources Control Board
URMP Urban Runoff Management Plan
WDR Waste Discharge Requirements
WPCD Water Pollution Control Drawings
WPCM Water Pollution Control Manager
WPCP Water Pollution Control Program
WQTR Water Quality Technical Report
SD San Diego
El Camino Real Widening Improvement Project
City of Carlsbad - Water Quality Technical Report
Final Report 8/3/2007
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INTRODUCTION
This Water Quality Technical Report (WQTR) is required under the City of Carlsbad's (City)
local Standard Urban Storm Water Mitigation Plan (SUSMP). The purpose of this report is to
document the process that was used to select and design the site, source, and treatment storm
water best management practices (BMPs) that will be incorporated in the project to mitigate the
impacts of urban runoff during and after construction. This WQTR is also intended to ensure
the effectiveness of the BMPs through proper long-term maintenance. In addition, a Storm
Water Pollution Prevention Plan (SWPPP) will be prepared under separate cover.
Appendix A, parts A through D, of the City of Carlsbad's SUSMP provides a checklist to
determine the projects SUSMP applicability. The applicable excerpts from these checklists are
provided in Table 1.
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Table 1. SUSMP Applicability Form
Part A: Determine Priority Project Permanent Storm Water BMP Requirements.
Does the project meet the definition of one or more of the priority project
categories?* Yes No
1 ."Detached residential development of 10 or more units" X
2. "Attached residential development of 10 or more units" X
3. "Commercial development greater than 100,000 square feet" X
4. "Automotive repair shop" X
5. "Restaurant" X
6. "Steep hillside development greater than 5,000 square feet" X
7. "Project discharging to receiving waters within Environmentally Sensitive
Areas" X
8. "Parking lot > 5,000 square feet or with > 15 parking spaces and potentially
exposed to urban runoff" X
9. "Streets, roads, highways, and freeways that would create a new paved
surface that is 5,000 square feet or greater" X
*Refer to the definitions section in the Storm Water Standards for expanded c
priority project categories.
efinitions of the
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.
El Camino Real Widening Improvement Project
City of Carisbad - Water Quality Technical Report
Final Report 8/3/2007
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Table 1. SUSMP Applicability Form (continued)
Part B: Determine Standard Permanent Storm Water Requirements.
Does the project propose: Yes No
1. "New impervious areas, such as rooftops, roads, parking lots, driveways,
paths and sidewalks?" X
2. "New pervious landscape areas and irrigation systems?" X
3. "Permanent structures within 100 feet of a natural water body?" X
4. "Trash storage areas?" X
5. "liquid or solid materials loading and unloading areas?" X
B. "Vehicle or equipment fueling, washing, or maintenance areas?" X
7. "Require a General NDPES Permit for Stonn Water Discharges Associated
with Industrial Activities (Except Construction)" X
8. "Commercial or industrial waste handling or storage, excluding typical office or
household waste" X
9. "Any grading or ground disturbance during construction?" X
10. "Any new storm drains, or alternation to existing storm drains?" X
•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 at, www.swrcb.ca.gopv/stormwtr/industrial.html
Part C: Determine Construction Phase Storm Water Requirements.
Would the project meet any of these criteria during construction? Yes No
1. "Is the project subject to California's statewide General NPDES Permit for
Storm Water Discharges Associated with Construction Activities?" X
2. "Does the project propose grading or soil disturbance?" X
3. 'Would storm water or urban runoff have the potential to contact any portion ol
the construction area, including washing and staging areas?" X
4. 'Would the project use any construction materials that could negatively affed
water quality if discharged from the site (such as, paints, solvents, concrete, and
stucco)?" X
Excerpt from Appendix A of the City of Carlsbad SUSMP.
A "yes" answer to any question in Part A results in the requirement for the project to comply with
the following:
• Priority Project Permanent Storm Water BMP Requirements; and
• Standard Permanent Storm Water BMP Requirements
A "yes" answer to any question in Part C results in the requirement for the project to comply with
the following:
• Construction Storm Water BMP Performance Standards
• Preparation of a Storm Water Pollution Prevention Plan (SWPPP)
El Camino Real Widening Improvement Project
City of Carlsbad - Water Quality Technical Report
Final Report 8/3/2007
An assessment of the construction site priority results in the classification of this project as
HIGH PRIORITY because it involves a site 5 acres or larger.
Since this project meets one or more of the SUSMP applicability criteria, it is required to
incorporate permanent storm water BMPs into the project design and prepare this Water Quality
Technical Report to document the steps taken to select appropriate BMPs. These BMPs
include site design, source control, and treatment control BMPs.
El Camino Real Widening Improvement Project
City of Carisbad - Water Quality Technical Report
Final Report 8/3/2007
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1.0 PROJECT DESCRIPTION
The project consists of the realignment and improvement of El Camino Real to include median
island streetscape and additional street widening of the roadway. Retaining walls, curb, gutter,
sidewalk, driveways and storm drain facilities will be constructed along the roadway.
A vicinity map, which identifies the project area, has been included in Appendix A. A site map
has also been included in Appendix A that indicates drainage areas, direction of flow, proposed
storm water conveyance systems, proposed treatment control BMPS, and pervious and
impervious areas.
1.1 TOPOGRAPHY AND LAND USE
The project occurs along a relatively flat valley with elevations ranging from approximately 80 ft
to 292 ft above mean sea level. The drainage tributary area is primarily residential.
1.2 HYDROLOGIC UNIT CONTRIBUTION
Table 2 identifies the hydrologic unit within the project limits. The hydrologic unit and area
numbers were taken from the Water Quality Control Plan for the San Diego Basin.
Table 2. Hydrologic Unit in Project Vicinity
Hydrologic Unit Hydrologic Area Name Hydrologic Unit
Basin Number
Carlsbad 904
Agua Hedionda Lagoon 904.31
Agua Hedionda Creek 904.32
A comparison of the acreage of the hydrologic area versus the contributing project area is
shown in Table 3. The project constitutes less than 0.0138 % of the area within the affected
watershed.
Table 3. Project Contributions to Watershed
Hydrologic
Area
Watershed Area, WA
(Acres)
Approximate Project
Area (Acres)
Estimated Project
Contribution (%)
904 134,400 18.5 0.0138
El Camino Real Widening Improvement Project
City of Carisbad - Water Quality Technical Report
Final Report 8/3/2007
2.0 WATER QUALITY ENVIRONMENT
2.1 BENEFICIAL USES
The descriptions of beneficial uses that are within the project limits or that the project discharges
directly to are contained in Table 4. Beneficial uses of inland surface waters, coastal waters,
and inland ground waters are contained in Tables 5, 6 and 7, respectively. The beneficial uses
for inland surface waters, coastal waters and ground waters must be protected as required by
the Water Quality Control Plan for the San Diego Basin and the Municipal Permit. Beneficial
uses were adopted and are to be used by the SD RWQCB and the nine RWQCBs uniformly
throughout all basins of the State. There are 23 beneficial uses within the San Diego Region, of
which 15 beneficial uses are within the project limits.
Table 4. Description of Beneficial Uses
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Beneficial Use
Designation Beneficial Use Description
MUM Municipal and
Domestic
Supply
Includes uses of water for community, military, or individual water supply
systems including, but not limited to, drinking water supply.
AGR Agricultural
Supply
Includes uses of water for farming, horticulture, or ranching including, but not
limited to, irrigation, stock watering, or support of vegetation for range
grazing.
IND Industrial
Services
Supply
Includes uses of water for industrial activities that do not depend primarily on
water quality including, but not limited to, mining, cooling water supply,
hydraulic conveyance, gravel washing, fire protection, or oil well re-
press urization.
RECl Contact
Recreation
Includes uses of water for recreational activities involving body contact with
water, where ingestion of water is reasonably possible. These uses include,
but are not limited to, swimming, wading, water-skiing, skin and SCUBA
diving, surfing, white water activities, fishing, or use of natural hot springs.
REC2 Non-Contact
Recreation
Includes the uses of water for recreational involving proximity to water, but
not normally involving body contact with water, where ingestion of water is
reasonably possible. These uses include, but are not limited to, picnicking,
sunbathing, hiking, camping, boating, tide pool and marine life study,
hunting, sightseeing, or aesthetic enjoyment in conjunction with the above
activities.
WARM Warm
Freshwater
Habitat
Includes uses of water that support warm water ecosystems including, but
not limited to, preservation or enhancement of aquatic habitats, vegetation,
fish or wildlife, including invertebrates.
WILD Wildlife Habitat Includes uses of water that support terrestrial ecosystems including, but not
limited to, preservation and enhancement of terrestrial habitats, vegetation,
wildlife, (e.g., mammals, birds, reptiles, amphibians, invertebrates), or wildlife
water and food sources.
coiyiiyi Commercial
and Sport
Fishing
Includes the uses of water for commercial or recreational collection of fish,
shellfish, or other organisms including, but not limited to, uses involving
organisms intended for human consumption or bait purposes.
EST Estuarine
Habitat
Includes uses of water that support inland saline water ecosystems
including, but not limited to, preservation or enhancement of estuarine
habitats, vegetation, fish, shellfish, or wildlife (e.g., estuarine mammals,
El Camino Real Widening Improvement Project
City of Carisbad - Water Quality Technical Report
Final Report 8/3/2007
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waterfowl, shorebirds).
Table 4. Description of Beneficial Uses (continued)
RARE Rare,
Threatened, or
Endangered
Species
Includes uses of water that support habitats necessary, at least in part, for
the survival and successful maintenance of plant or animal species
established under state or federal law as rare, threatened or endangered.
MAR Marine Habitat Includes uses of water that support marine ecosystems including, but not
limited to, preservation and enhancement of terrestrial habitats, vegetation
such as kelp, fish, shellfish, of wildlife (e.g., marine mammals, shorebirds).
AQUA Aquaculture Includes uses of water for aquaculture or mariculture operations including,
but not limited to, propagation, cultivation, maintenance, or harvesting of
aquatic plants and animals for human consumption or bait purposes.
MIGR Migration of
Aquatic
Organisms
Includes the uses of water that support habitats necessary for migration,
acclimatization between fresh and salt water, or other temporary activities by
aquatic organisms, such as anadromous fish.
SPWN Spawning,
Reproduction,
and/or Early
Development
Includes uses of water that support high quality aquatic habitats suitable for
reproduction and early development of fish. This use is applicable only for
the protection of anadromous fish.
SHELL Shellfish
Han/esting
Includes uses of water that support habitats suitable for the collection of
filter-feeding shellfish (e.g., clams, oysters and mussels) for human
consumption, commercial, or sport purposes.
Excerpt from Water Quality Control Plan for the San Diego Basin.
2.1.1 INLAND SURFACE WATERS
Table 5. Beneficial Uses of Inland Surface Waters
Hydrologic Area Basin
Number
M
U
N
A
G
R
1
N
D
R
E
0
1
R
E
C
2
W
A
R
M
W
1
L
D
Inland Surface Waters
Agua Hedionda Creek 904.32
Existing Beneficial Use
El Camino Real Widening Improvement Project
City of Carlsbad - Water Quality Technical Report
Final Report 8/3/2007
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2.1.2 COASTAL WATERS
Table 6. Beneficial Uses of Coastal Waters
Hydrologic Area Basin
Number
1
N
D
R
E
C
1
R
E
C
2
C
0
M
M
E
S
T
W
1
L
D
R
A
R
E
M
A
R
A
Q
U
A
M
1
G
R
S
P
W
N
S
H
E
L
L
Coastal Waters
Agua Hedionda Lagoon 904.31
• Existing Beneficial Use
2.1.3 GROUNDWATER
Table 7. Beneficial Uses of Inland Ground Waters
Hydrologic Area Basin
Number
M
U
N
A
G
R
1
N
D
Ground Waters
Los Monos 904.31 • • •
Existing Beneficial Use
2.2 303(d) STATUS
The nearest downstream impaired water bodies are listed below.
Table 8. 303 (d) Water Bodies Listed with Constituents of Concern
Hydrologic
Descriptor Water body Pollutant/
Stressor
TMDL
Priority
Extent of
Impairment
Agua Hedionda Agua Hedionda Bacteria Indicators Low 6.8 acres
lagoon Lagoon
m (HA 904.31) Sedimentation/ low 6.8 acres
III
(HA 904.31)
Siltation
Agua Hedionda
Creek
(HA 904.32)
Agua Hedionda
Creek
Total Dissolved
Solids (Nutrients)
low 7 miles
Excerpt from 2002 CWA 3a3(d) List
El Camino Real Widening Improvement Project
City of Carisbad - Water Quality Technical Report
Final Report 8/3/2007
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3.0 CHARACTERIZATION OF PROJECT RUNOFF
3.1 EXISTING AND POST-CONSTRUCTION DRAINAGE
ii
Flow Patterns
The proposed project will not significantly alter drainage patterns on the site. The site map,
included in Appendix A, shows a graphic description of the flow patterns on the site.
Flow Rates
The water quality flow was calculated for this report using the 0.2-in/hr intensity storm
associated with the 85*^ percentile storm event as required by numeric sizing treatment
standards for flow based BMPs. The hydrology map showing the locations of the subbasins
within the project area is presented in Appendix B. Treatment flow rates are included in
Table 9. A complete preliminary Hydrology and Hydraulics Report for El Camino Real
Improvement Project is available for review at the City.
Table 9. Post-Construction Flows
Area Area
(acres)
QwQ
(cfs) Location Description
A 0.70 0.126 East section of El Camino Real between Sta. 532+00 and Sta. 540+00
including access road to Sprague properties
B 0.60 0.108 West section of El Camino Real between Sta. 532+00 and Sta. 540+00
C 0.80 0.144 East section of El Camino Real between Sta. 526+00 and Sta. 532+00
D 0.80 0.144 West section of El Camino Real between Sta. 526+00 and Sta. 532+00
E 1.10 0.198 East section of El Camino Real between Sta. 517+50 and Sta. 526+00
F 1.10 0.198 West section of El Camino Real between Sta. 517+50 and Sta. 526+00
G 0.80 0.144 East section of El Camino Real between Sta. 512+00 and Sta. 517+50
H 0.80 0.144 West section of El Camino Real between Sta. 512+00 and Sta. 517+50
1 0.60 0.108 East section of El Camino Real between Sta. 507+00 and Sta. 512+00
J 0.60 0.108 West section of El Camino Real between Sta. 507+00 and Sta. 512+00
K 1.15 0.207 East section of El Camino Real between Sta. 498+50and Sta. 507+00
L 1.15 0.207 West section of El Camino Real between Sta. 498+50 and Sta. 507+00
Refer to El Camino Real Drainage Exhibit in Appendix B for area locations
3.2 POST-CONSTRUCTION EXPECTED DISCHARGES
Currently, El Camino Real consists of a four-lane street (two northbound lanes and two
southbound lanes) as well as a median. As such, the pollutants of concern before
commencement of construction activities include those listed in Table 10 on the next page for
the Streets, Highways and Freeways project category.
El Camino Real Widening Improvement Project
City of Carlsbad - Water Quality Technical Report
Final Report 8/3/2007
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Table 10 also lists potential pollutants of concern from the proposed project based on the
applicable project category of Streets, Highways and Freeways, since the proposed project
consists of the widening of the street to a six-lane street (three northbound lanes and three
southbound lanes). These pollutants are the same pollutants generated prior to construction.
Table 11 describes these pollutants and their possible sources.
Table 10. Anticipated and Potential Pollutants Generated By Land Use Type^
General Pollutant Categories
Project
Categories Sediment Nutrients Heavy
Metals
Organic
Compounds
Trash &
Debris
Oxygen
Demanding
Substances
Oil&
Grease
Bacteria &
Virus Pesticides
Streets,
Highways
And
Freeways X p(i) X X p{5} X
X= anticipated
P = potential
(1) A potential pollutant if landscape exists on-site.
(4) Including petroleum hydrocarbons.
(5) Including solvents.
Excerpt from Table 2 of City of Carlsbad SUSMP
Table 11. General Pollutant Categories and Descriptions
Sediments
Sediments are soils or other surficial materials eroded and then transported or
deposited by the action of wind, water, ice, or gravity. Sediments can increase
turbidity, clog fish gills, reduce spawning habitat, lower young aquatic organisms
survival rates, smother bottom dwelling organisms, and suppress aquatic vegetation
growth.
Nutrients
Nutrients are inorganic substances, such as nitrogen and phosphorus. They
commonly exist in the form of mineral salts that are either dissolved or suspended in
water. Primary sources of nutrients in urban runoff are fertilizers and eroded soils.
Excessive discharge of nutrients to water bodies and streams can cause excessive
aquatic algae and plant growth. Such excessive production, referred to as cultural
eutrophication, may lead to excessive decay of organic matter in the water body, loss
of oxygen in the water, release of toxins in sediment, and the eventual death of aquatic
organisms.
Heavy
Metals
Metals are raw material components in non-metal products such as fuels, adhesives,
paints, and other coatings. Primary source of metal pollution in storm water are
typically commercially available metals and metal products. Metals of concern include
cadmium, chromium, copper, lead, mercury, and zinc, lead and chromium have been
used as corrosion inhibitors in primer coatings and cooling tower systems. At low
concentrations naturally occurring in soil, metals are not toxic. However, at higher
concentrations, certain metals can be toxic to aquatic life. Humans can be impacted
from contaminated groundwater resources, and bioaccumulation of metals in fish and
shellfish. Environmental concems, regarding the potential for release of metals to the
environment, have already led to restricted metal usage in certain applications.
El Camino Real Widening Improvement Project
City of Carlsbad - Water Quality Technical Report
Final Report 8/3/2007
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Table 11. General Pollutant Categories and Descriptions (continued)
Organic
Compounds
Organic compounds are cartjon-based. Commercially available or naturally occurring
organic compounds are found in pesticides, solvents, and hydrocarbons. Organic
compounds can, at certain concentrations, indirectly or directly constitute a hazard to
life or health. When rinsing off objects, toxic levels of solvents and cleaning
compounds can be discharged to storm drains. Dirt, grease, and grime retained in the
cleaning fluid or rinse water may also adsorb levels of organic compounds that are
harmful or hazardous to aquatic life.
Trash &
Debris
Trash (such as paper, plastic, polystyrene packing foam, and aluminum materials) and
biodegradable organic matter (such as leaves, grass cuttings, and food waste) are
general waste products on the landscape. The presence of trash & debris may have a
significant impact on the recreational value of a water body and aquatic habitat.
Excess organic matter can create a high biochemical oxygen demand in a stream and
thereby lower its water quality. Also, in areas where stagnant water exists, the
presence of excess organic matter can promote septic conditions resulting in the
growth of undesirable organisms and the release of odorous and hazardous
compounds such as hydrogen sulfide.
Oxygen-
Demanding
Substances
This category includes biodegradable organic material as well as chemicals that react
with dissolved oxygen in water to form other compounds. Proteins, carbohydrates, and
fats are examples of biodegradable organic compounds. Compounds such as
ammonia and hydrogen sulfide are examples of oxygen-demanding compounds. The
oxygen demand of a substance can lead to depletion of dissolved oxygen in a water
body and possibly the development of septic conditions.
Oil and
Grease
Oil and grease are characterized as high-molecular weight organic compounds.
Primary sources of oil and grease are petroleum hydrocarbon products, motor
products from leaking vehicles, esters, oils, fats, waxes, and high molecular-weight
fatty acids. Introduction of these pollutants to the water bodies are very possible due to
the wide uses and applications of some of these products in municipal, residential,
commercial, industrial, and construction areas. Elevated oil and grease content can
decrease the aesthetic value of the water body, as well as the water quality.
El Camino Real Widening Improvement Project
City of Carlsbad - Water Quality Technical Report
Final Report 8/3/2007
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4.0 MITIGATION MEASURES TO PROTECT WATER QUALITY
To address the water quality concerns identified above, BMPs will be implemented during
construction and post-construction. According to Table 1 of the City of Carisbad's SUSMP which
has been excerpted in Table 12 below, post-construction site design, source control, and
selected treatment control BMPs will be required for the project.
Table 12. BMPs Applicable to Priority Projects
Site
Design
BMPs'^>
Source
Control
BMPs*^*
BMPs Applicable to Individual Priority
Project Categor es
00
r
ffi >
B Co
C Q. CD .r-"D «
CC CD
(D
E
Q.
'Z3
LU
<
CJ>
c
CO Q.
0
I
CO
Treatment
Control
BMPs
Standard Projects R R O O O O O O O O O O O
Priority Projects:
Streets, Highways &
Freeways
R R
R = Required; select one or more applicable and appropriate BMPs from the applicable steps in Section III.2.A-D of
the City of Carisbad SUSMP, or equivalent as identified in Appendix C of the City of Carisbad SUSMP.
O = Optional or may be required by City staff. As appropriate, applicants are encouraged to incorporate treatment
control BMPs and BMPs applicable to individual priority project categories into the project design. City staff may
require one or more of these BMPs, where appropriate.
S = Select one or more applicable and appropriate treatment control BMPs from Appendix C of the City of Carisbad
SUSMP.
(1) Refer to Section III.2.A of the City of Carisbad SUSMP.
(2) Refer to Section III.2.B of the City of Carisbad SUSMP.
(3) Priority project categories must apply specific storm water BMP requirements, where applicable. Priority projects
are subject to the requirements of ail priority project categories that apply.
(4) Refer to Section III.2.D of the City of Carisbad SUSMP.
Excerpt from Table 1 of City of Carisbad SUSMP
4.1 CONSTRUCTION BMPS
This project will be covered under the General Construction Storm Water Permit, NPDES Order
99-08-DWQ. The project plans will cover construction site BMPs, more descriptive information
on these BMPs can be found in the SWPPP. The SWPPP will have a Sampling and Monitoring
Program that addresses both direct discharges from the project into a Section 303(d) water
body and discharges that have been discovered through visual monitoring to be potentially
contaminated by pollutants not visually detectable in the runoff.
El Camino Real Widening Improvement Project
City of Carisbad - Water Quality Technical Report
Final Report 8/3/2007
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The Municipal Permit requires that every project to be designated with a priority: high, medium
or low where there is a need for construction storm water BMPs. The El Camino Real
Improvement Project is considered a High Priority project based on criteria established by the
City. The SWPPP addresses this issue and the priority has been noted on the contract plans as
required by the City. Additionally, Water Pollution Control Drawings (WPCD) have been
developed and are included in contract plans to address temporary BMPs during the
construction phase. Selected construction BMPs are included in Table 13. Categories and BMP
names are consistent with the State of California Department of Transportation Storm Water
Quality Handbooks - Construction Site BMPs Manual (March 2003).
Table 13. Selected Construction Site BMPs
BMP
ID NAME
Included as
Narrative/Contract
Item/Both
TEMPORARY SOIL STABILIZATION
SS-1 Scheduling Narrative
SS-2 Preservation of Existing Vegetation Narrative
SS-4 Hydro Seeding Both
SS-5 Soil Binders Both
SS-7 Geotextiles, Plastic Covers. & EC Blankets/Mats Both
SS-9 Earth Dikes/Drainage Swales & Ditches Both
SS-10 Outlet Protection/Velocity Dissipation Devices Both
TEMPORARY SEDIMENT CONTROL
SC-1 Silt Fence Both
SC-3 Sediment Trap Both
SC-4 Check Dam Both
SC-5 Fiber Rolls Both
SC-6 Gravel Bag Berm Both
SC-7 Street Sweeping and Vacuuming Narrative
SC-8 Gravel Bag Barrier Both
SC-10 Storm Drain Inlet Protection Both
WIND EROSION CONTROL
WE-1 Wind Erosion Control Narrative
TRACK NG CONTROL
TC-1 Stabilized Construction Entrance/Exit Both
TC-2 Construction Road Stabilization Narrative
NON-STORM WATER MANAGEMENT
NS-1 Water Conservation Practices Narrative
NS-2 Dewatering Operations Narrative
NS-3 Paving and Grinding Operations Narrative
NS-7 Potable Water/Irrigation Narrative
NS-8 Vehicle and Equipment Cleaning Narrative
NS-9 Vehicle and Equipment Fueling Narrative
NS-10 Vehicle and Equipment Maintenance Narrative
El Camino Real Widening Improvement Project
City of Carisbad - Water Quality Technical Report
Final Report 8/3/2007
15
Table 13. Selected Construction Site BMPs (continued)
ii
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BMP
ID NAME
Included as
Narrative/Contract
item/Both
WASTE MANAGEMENT AND MATERIALS POLLUTION CONTR OL
WM-1 Material Delivery and Storage Narrative
WM-2 Material Use Narrative
WM-3 Stockpile Management Narrative
WM-4 Spill Prevention and Control Narrative
WM-5 Solid Waste Management Narrative
WM-6 Hazardous Waste Management Narrative
WM-8 Concrete Waste Management Narrative
WM-9 Sanitary/Septic Waste Management Narrative
WM-10 Liquid Waste Management Narrative
4.2 POST-CONSTRUCTION BMPS
BMPs will be implemented to address water quality impacts during the planning and design, and
operational stages of this project. The general categories of BMPs that have been identified for
use are shown in Table 14. Specific BMP descriptions are presented in Sections 4.2.1 through
4.2.3 of this report.
Table 14. BMP Categories and Descriptions
ii
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Category Description
Site Design BMPs
Any project design feature that reduces the creation or severity of
potential pollutant sources or reduces the alteration of the project site's
natural flow reqime.
Source Control BMPs
Land use or site planning practices or structures that aim to prevent
urban runoff pollution by reducing the potential for contamination at the
source of pollution. Source control BMPs minimize contact between
pollutants and site runoff (covers over trash bins, berms around fuel
dispensers)
Treatment BMPs
An engineered system designed and constructed to remove pollutants
from urban runoff. Pollutant removal is achieved by simple gravity
settling of particulate pollutants, filtration, biological uptake, media
absorption or any other physical, biological, or chemical process.
El Camino Real Widening improvement Project
City of Carisbad - Water Quality Technical Report
Final Report 8/3/2007
16
4.2.1 SITE DESIGN BMPs
The following site design BMPs have been incorporated into the project design and are
standard technology-based, non-treatment controls selected to reduce pollutant discharges to
the maximum extent possible (MEP) requirements.
Maintain Pre-Development Rainfall Runoff Characteristics
• Minimize impervious footprint to the MEP
• Conserve natural areas
• Minimize directly connected impervious areas
• Maximize canopy interception and water conservation
Protect Slopes and Channels
• Convey runoff safely from the tops of slopes
• Vegetate slopes with native or drought tolerant vegetation
• Stabilize permanent channel crossings
• Install energy dissipaters at the outlets of new storm drains, culverts, conduits, or
channel that enter unlined channels
4.2.2 SOURCE CONTROL BMPs
The following source control BMPs have been incorporated into the project design and are
control measures used on disturbed areas to reduce the potential for discharge of sediment or
other pollutants into storm water runoff. Source controls prevent or limit the exposure of
materials to storm water at the source.
Use Efficient Irrigation Svstems and Landscape Design
• Employ rain shutoff devices to prevent irrigation during precipitation
• Design irrigation systems to each landscape areas' specific water requirements
Provide Storm Water Convevance Svstem Stenciling and Signage
• Provide concrete stamping, porcelain tile, inset permanent marking or equivalent of all
storm water conveyance system inlets and catch basins within the project area with
prohibitive language (e.g., "No Dumping - 1 Live Downstream), satisfactory to the City
Engineer.
• Post signs and prohibitive language and/or graphical icons, which prohibit illegal
dumping at public access points along channel and creeks within the project area.
BMPs applicable to individual priority project categories present on the construction site include
the following:
Ei Camino Real Widening Improvement Project
City of Carisbad - Water Quality Technical Report
Final Report 8/3/2007
17
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Private Roads
Incorporate, to the extent practicable:
1. Rural swale system - street sheet flows to native planted swale or gravel shoulder,
curbs at street corners, culverts under driveways and street crossings;
2. Urban curiD/swale system - street slops to curb, periodic swale inlets drain to native
planted swale; or
3. Dual drainage system - first flush captured in street catch basins and discharged to
adjacent native planted swale or gravel shoulder,
4. Other treatment control BMP methods approved by the City Engineer to reduce storm
water runoff pollution.
Residential Drivewavs 8i Guest Parking
Driveways shall have, to the extent practicable, one of the following:
1. Shared access;
2. Flared entrance (single lane at street);
3. Wheelstrlps (paving only under tires); or
4. Designed to drain into landscaping prior to discharging to the storm water conveyance
system.
Hillside Landscaping
Hillside areas disturbed by project development shall be landscaped with deep-rooted, drought
tolerant plant species selected for erosion control.
4.2.3 TREATMENT BMPs
This project is considered a priority project and is therefore required to incorporate treatment
BMPs into the site. Based on the impaired watenways that exists downstream of the project
area and the pollutants generated by the site, this project will incorporate treatment control
BMPs designed to remove sedimentation/siltation and nutrients, which are the primary
pollutants of concern.
Table 15 on the next page was developed as part of the model SUSMP to aid in selecting the
appropriate BMPs based on pollutants associated with the project category.
Ei Camino Real Widening improvement Project
City of Carisbad - Water Quality Technical Report
Final Report 8/3/2007
18
Table 15. Structural Treatment Control BMP Selection Matrix^
Pollutant of
Concern
Treatment Control BMP Categories
Pollutant of
Concern Nathre
Planted
Swales
Detention
Basins
Infiltration
Basins
Wet
Ponds or
Wetlands
Drainage
Inserts
Filtration Hydrodynamic
Separator
Systems
Sediment M H H H . I H M
Nutrients L M M M I M I
Heavy Metals M M M H I H I
Organic
Compounds U U U U L M L
Trash &
Debris I H U U M H M
Oxygen
Demanding
Substances
I M M M I M L
Oil & Grease M M U U L H L
Pesticides U U U U L U L
(1) Including trenches and porous paving.
(2) Also know as hydrodynamic devices and baffle boxes.
L: Low removal efficiency
M: Medium removal efficiency
H: High removal efficiency
U: Unknown removal efficiency
Sources: Guidance Specifying Management Measures for Sources ofNonpoint Pollution in
Coastal Waters (1993). National Stonnwater Best Management Practices Database (2001), and
Guide for BMP Selection in Urban Developed Areas (2001).
Excerpt from Table 4 of the City of Carisbad SUSMP
Native planted swales will be used to treat water quality for the project. Native planted swales
will be located either along the side of the roadway in the partway area or in the median, as
determined by the City during the final design phase of the project. The native planted swales
will drain the first flush runoff to the curtD inlets located along the street. The swales will either
connect to the back of the curb inlets via an opening on the back or will drain to grated catch
basins that will then connect to the curb inlets.
The native planted swales will consist of thick vegetation that is slow and low-growing. Since
they will not be irrigated, the chosen vegetation will also be drought-tolerant. The growth height
will be approximately 12-inches. Finally, any vegetation used will be from the City approved list
and/or manual.
El Camino Real Widening improvement Project
City of Carisbad - Water Quality Technical Report
Final Report 8/3/2007
19
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Treatment flows for the native planted swales were determined based on the rational method
and flow based numeric sizing treatment standards identified in the City of Carisbad SUSMP
Storm Water Standards. The C value for the required treatment area was determined to be 0.90
based on the San Diego County Hydrology Manual, as follows:
C = [0.90 X (% Impervious)] + [Cp x (1 - % Impervious)]
C = (0.90x1) + [0x(1 -1)]
C = 0.90
The intensity for the subbasins is 0.2-in/hr based on the City of Carisbad SUSMP Storm Water
Standards. Areas were measured using AutoCAD. Appendix C contains the water quality
treatment flow calculations in Worksheet 1 and the native planted swale length calculations in
Worksheet 2 (one sheet for each subbasin). The native planted swale length calculations were
based on design guidelines developed by the California Stormwater Quality Association
(CASQA) Stormwater Best Management Practices Handbook, treatment control BMP No. TC-
30 - Vegetated Swale. Specifically, the length of the native planted swales is determined using
Manning's equation with the flow rate calculated based on the rational method, the geometry of
the swale having 3:1 side slopes and a bottom width of 1.5 ft, and using an "n" value of 0.25.
This information was used to determine the velocity and depth of the flow. Based on a retention
time of 10 minutes, the swale length in feet was calculated by multiplying 10 minutes by the
velocity in feet per second by 60 seconds per minute. Although the roadway slope is steeper
than 3%, a stepped system of native planted swales will be used to maintain the flow through
the swales at the maximum 2.5% allowed for this treatment system. The swale lengths are
summarized in Table 16 on the next page.
Table 16. Native Planted Swale Lengths
Sub-
Basin
Area
(acres)
QwQ
(cfs)
Upper
Elev.
(ft)
Lower
Elev.
(ft)
Available
Length (ft)
Road
Slope
Swale
Slope
Velocity
(ft/s)
Depth
(ft)
Swale
Length
(ft)
A 0.70 0.126 247 214 600 0.055 0.025 0.28 0.21 168
B 0.60 0.108 247 214 600 0.055 0.025 0.26 0.20 156
C 0.80 0.144 214 170 835 0.053 0.025 0.29 0.23 174
D 0.80 0.144 214 170 835 0.053 0.025 0.29 0.23 174
E 1.10 0.198 170 146 530 0.045 0.025 0.32 0.27 192
F 1.10 0.198 170 146 530 0.045 0.025 0.32 0.27 192
G 0.80 0.144 146 127 470 0.040 0.025 0.29 0.23 174
H 0.80 0.144 146 127 470 0.040 0.025 0.29 0.23 174
1 0.60 0.108 127 94 835 0.040 0.025 0.26 0.20 156
J 0.60 0.108 127 94 835 0.040 0.025 0.26 0.20 156
K 1.15 0.207 94 84 320 0.031 0.025 0.32 0.28 192
L 1.15 0.207 94 84 320 0.031 0.025 0.32 0.28 192
Refer to El Camino Real Drainage Exhibit in Appendix B for area locations.
Ei Camino Real Widening improvement Project
City of Carisbad - Water Quality Technical Report
Final Report 8/3/2007
20
4.3 OPERATION AND MAINTENANCE PLAN
The City will implement all maintenance operations of permanent BMPs as outlined in Section
2.5 (Maintenance of Municipal Separate Storm Sewer System (MS4) of their Jurisdictional
Urban Runoff Management Plan (JURMP). The Contractor is responsible for maintenance of
construction BMPs.
Operation and Maintenance Requirements for the proposed permanent BMPs are provided in
Table 17.
El Camino Real Widening Improvement Project
City of Carisbad - Water Quality Technical Report
Final Report 8/3/2007
21
iiiitiiiiiiiftiiiiiii llllllllllillli
Table 17. Permanent BMP Operation and Maintenance Requirements
Design Criteria,
Routine Actions Maintenance Indicator Field Measurement Measurement
Frequency Maintenance Activity
Native Planted Swales -
Inspect for erosion, damage
to vegetation, and sediment
and trash/debris
accumulation
Presence of erosion,
missing vegetation, and
accumulation of
sedimentation and/or
debris/trash that could
interfere with proper
functioning of swale.
Visual observation of
erosion, damaged
vegetation, and
presence of sediment
and trash/debris.
Once per year
(preferably at the
beginning of the rainy
season - October 1 ).
Reinforce eroded areas with rock
riprap.
Reseed areas with damaged
vegetation.
Remove and properiy dispose of
accumulated sediment when it
exceeds a 3-inch depth.
Remove and properiy dispose of
debrisArash.
Shrubbery Trimming High growth of shrubbery
and presence of weeds
and/or woody vegetation.
Visual observation of
shrubbery height
exceeding a 6-inch
depth and presence of
weeds and/or woody
vegetation.
Trim once per year for
aesthetic and safety
purposes and/or
suppression of
shrubbery and woody
vegetation.
Trim shrubbery to no less than 4-
inch depth, but no taller than 6-inch
depth.
Weed control strategies.
Inspection for standing water Standing water is present
and does not drain after a
maximum of 72 hours.
Visual observation of
standing water.
Once per year
(preferably at the
beginning of the rainy
season - October 1 ).
Regrade areas downstream of
location where standing water
accumulates to ensure water flows
smoothly.
22
El Camino Real Widening Improvement Project
City of Carisbad - Water Quality Technical Report
Final Report 8/3/2007
5.0 FISCAL RESOURCES
The City of Carisbad Public Works Department will maintain the native planted swales in
accordance with the maintenance requirements in Table 17.
6.0 FISCAL RESOURCES
The City of Carlsbad Public Works Department will fund the maintenance of the native planted
swales. The City of San Diego 2006 cost data lists $5.50/LF for native planted swales. The total
linear feet required for the project is approximately 1840 resulting in a total cost of
approximately $10,120 for the native planted swales.
7.0 CONCLUSIONS
It is our conclusion that the project design measures and proposed BMPs will provide
conformance with applicable requirements under the NPDES Municipal Permit and the related
City of Carisbad SUSMP requirements.
m
El Camino Real Widening improvement Project
City of Carisbad - Water Quality Technical Report
Final Report 8/3/2007
23
8.0 REFERENCES
City of Carlsbad, Public Works Department, Standard Urban Storm Water Mitigation Plan,
Storm Water Standards (April 2003)
City of Carlsbad, Jurisdictional Urban Runoff Management Program (February 21, 2002)
Model Standard Urban Storm Water Mitigation Plan (SDRWQCB approved 6/12/02)
Storm Water Quality Handbooks: Project Planning and Design Guide (Caltrans 2002)
Storm Water Quality Handbooks: Construction Site Best Management Practices (BMPs) Manual
(Caltrans, March 2003)
County of San Diego, Operation and Maintenance Requirements for Treatment Controls
(Draft- November 2002)
EPA's Storm Water Phase II Menu of Best Management Practices (BMPs) Post-Construction
Storm Water Management in New Development & Redevelopment
*i URL: http://cfpub.epa.gov/npdes/stormwater/menuofbmps/menu.cfm
Ei Camino Real Widening improvement Project
City of Carisbad - Water Quality Technical Report
Final Report 8/3/2007
24
APPENDIX A
VICINITY AND SITE MAP
m
BEST OWGINAL
PAcmc
OCEAN
Figure
Vicinity Map
V. ^—; EL CAMINO REAL ROAD WIDENING
SITE MAP (BMP LOCATION MAP)
BMP BOUNDARY
SWALE
SUB-BASIN ID
AREA TO EACH SWALE
EXISTING STORM DRAIN
PROPOSED STORM DRAIN
CURB INLET
TYPE F CATCH BASIN
BROW DITCH
RIP RAP
iiQIt
TREATMENT LENGTH IS LOCATED ONE SUB-BASIN
DOWNSTREAM OF SUB-BASIN ID INDICATED.
Bureau Veritas North America
11590 West Bernardo Court, Suite 100
San Diego. CA 92127-1624
•iTtiy Tel: (858) 451-6100. Fax: (858) 451-2846
www.us.bureauveritas.com
SHiilffit-J
APPENDIX B
EL CAMINO REAL DRAINAGE EXHIBIT
NOTEBAaSOFTOPOORAPHCMAPPWG
t) TOPOGRAPHIC MAPPING FROM CITY OF CARLSBAD
PROJECT NAME: CARLSBAD SEWER
PROJECT NUMBER: 290502 OATE OF PHOTOGRAPHY: 3/9/2002
APPROXIMATE 250 FEET IN WIDTH ALONG a CAMINO REAL
COMPILED WITH:
2) CrrY OF CARLSBAD GIS TOPOGRAPHIC MAPPING DATED 12/20/05
FOR SURROUNDING AREAS
Berryman & Henigat
11590 West Bernardo Court Suite 100
San Diego. CA 92127-1624
Tel: (858) 451-6100 Fax: (858) 451-2846
www.us.tHjreauve rltas.com
APPENDIX C
WATER QUALITY TREATMENT CALCULATIONS
Worksheet 1
Water Quality Treatment Flow Calculations
Upper lower Length'^' Roadway Swale
Subbasin C 1 (in/hr) A (acres) Q (Cfs) Elev (ft) Elev (ft) (ft) Slope Slope
A 0.90 0.2 0.70 0.126 247 214 600 0.055 0.025
B 0.90 0.2 0.60 0.108 247 214 600 0.055 0.025
C 0.90 0.2 0.80 0.144 214 170 835 0.053 0.025
D 0.90 0.2 0.80 0.144 214 170 835 0.053 0.025
E 0,90 0.2 1.10 0.198 170 146 530 0.045 0.025
F 0.90 0.2 1.10 0.198 170 146 530 0.045 0.025
G 0.90 0.2 0.80 0.144 146 127 470 0.040 0.025
H 0.90 0.2 0.80 0.144 146 127 470 0.040 0.025
1 0.90 0.2 0.60 0.108 127 94 835 0.040 0.025
J 0.90 0.2 0.60 0.108 127 94 835 0.040 0.025
K 0.90 0.2 1.15 0.207 94 84 320 0.031 0.025
L 0.90 0.2 1.15 0.207 94 84 320 0.031 0.025
(1) Treatment length is located one subbasin downslope of subbasin letter indicated.
Worksheet 2
Design Procedure Form for Native Planted Swale
Designer: Sharon L. Humphreys
Company: Bureau Veritas
Date: 1/10/2007
Project: Ei Camino Real Widening Project - Between Tamarack and Chestnut. Carisbad, CA
location Subbasin A
1. Determine Design Fiow
(Use Worksheet 1) QBMP -
i =
0.126 cfs
100 %
2. Swale Geometry
a. Swale Bottom Width (b)
b. Side slope (z)
c. Flow direction slope (s)
1.5 ft
3
2.5 %
3. Design flow velocity (Manning n = 0.25} V = 0.28 ft/s
4. Depth of flow (D) D= 0.21 ft
5. Design Length (L)
L = (10 min) x (flow velocity, ft/sec) x (60 sec/min) 1= 168.0 ft
6. Vegetation (describe)
Any fine, close-growing, water-resistant
grass approved by the City.
7. Ouflow Collection (check type used or describe "other")
I = (10 min) X (flow velocity, ft/sec) x (60 sec/min) Grated Inlet
infiltration Trench
Underdrain
X other Curb Inlet
Notes:
Length available for native planted swale is 600' so it will be an effective treatment technology.
Worksheet 2
Design Procedure Form for Native Planted Swale
Designer: Sharon L. Humphreys
Company: Bureau Veritas
Date: 8/16/2006
Project: El Camino Real Widening Project - Between Tamarack and Chestnut. Carisbad, CA
Location Subbasin B
1. Determine Design Flow
(Use Worksheet 1) QBMP -
i -
0.108 cfs
100 %
2. Swale Geometry
a. Swale Bottom Width (b)
b. Side slope (z)
c. Flow direction slope (s)
b =
z -
s =
1.5 ft
3
2.5 %
3. Design fiow velocity (Manning n = 0.25) v -0.26 ft/s
4. Depth of flow (D) D = 0.20 ft
5. Design length (L)
L = (10 min) x (flow velocity, ft/sec) x (60 sec/min) 1 = 156.0 ft
6. Vegetation (describe)
Any fine, close-growing, water-resistant
grass approved by the City.
7. Ouflow Collection (check type used or describe "other")
L = (10 min) x (fiow velocity, ft/sec) x (60 sec/min) Grated inlet
Infiltration Trench
Underdrain
X other Curb inlet
Notes:
Length available for native planted swale is 600' so it will be an effective treatment technology.
Worksheet 2
Design Procedure Form for Native Planted Swale
Designer: Sharon L. Humphreys
Company: Bureau Veritas
Date: 8/16/2006
Project: Ei Camino Real Widening Project - Between Tamarack and Chestnut. Carisbad, CA
Location Subbasin C
1. Determine Design Flow
(Use Worksheet 1) QBMP -
i -
0.144 cfs
100 %
2. Swale Geometry
a. Swale Bottom Width (b)
b. Side slope (z)
c. Fiow direction slope (s) II II II 1.5 ft
3
2.5 %
3. Design flow velocity (Manning n = 0.25) v -0.29 ft/s
4. Depth of flow (D) D = 0.23 ft
5. Design Length (L)
L = (10 min) x (flow velocity, ft/sec) x (60 sec/min) 1 = 174.0 ft
6. Vegetation (describe)
Any fine, close-growing, water-resistant
grass approved by the City.
7. Ouflow Collection (check type used or describe "other")
L = (10 min) x (flow velocity, ft/sec) x (60 sec/min) Grated inlet
infiltration Trench
Underdrain
X other Curb Inlet
Notes:
Length available for native planted swale is 835' so it wili be an effective treatment technology.
Worksheet 2
Design Procedure Form for Native Planted Swale
Designer: Sharon L. Humphreys
Company: Bureau Veritas
Date: 8/16/2006
Project: El Camino Real Widening Project - Between Tamarack and Chestnut. Carisbad, CA
Location Subbasin D
1. Determine Design Flow
(Use Worksheet 1) 0 BMP -0.144 cfs
100 %
2. Swale Geometry
a. Swale Bottom Width (b)
b. Side slope (z)
c. Fiow direction slope (s)
b = 1.5 ft
z = 3
s = 2.5 %
3. Design fiow velocity (Manning n = 0.25) v = 0.29 ft/s
4. Depth of flow (D) D = 0.23 ft
5. Design Length (L)
L = (10 min) x (flow velocity, ft/sec) x (60 sec/min) L= 174.0 ft
6. Vegetation (describe)
Any fine, close-growing, water-resistant
grass approved by the City.
7. Ouflow Collection (check type used or describe "other")
L = (10 min) x (fiow velocity, ft/sec) x (60 sec/min) Grated inlet
infiltration Trench
Underdrain
X Other Curb inlet
Notes:
Length available for native planted swale is 835' so it will be an effective treatment technology.
Worksheet 2
Design Procedure Form for Native Planted Swale
Designer: Sharon L. Humphreys
Company: Bureau Veritas
Date: 8/16/2006
Project: Ei Camino Real Widening Project - Between Tamarack and Chestnut. Carisbad, CA
Location Subbasin E
1. Determine Design Flow
(Use Worksheet 1) QBMP -
i =
0.198 cfs
100 %
2. Swale Geometry
a. Swale Bottom Width (b)
b. Side slope (z)
c. Fiow direction slope (s)
1.5 ft
3
2.5 %
3. Design flow velocity (Manning n = 0.25) V = 0.32 ft/s
4. Depth of flow (D) D = 0.27 ft
5. Design Length (L)
I = (10 min) x (fiow velocity, ft/sec) x (60 sec/min) 1= 192.0 ft
6. Vegetation (describe)
Any fine, close-growing, water-resistant
grass approved by the City.
7. Ouflow Collection (check type used or describe "other")
I = (10 min) X (fiow velocity, ft/sec) x (60 sec/min) Grated inlet
infiltration Trench
Underdrain
X Other Curb Inlet
Notes:
length available for native planted swale is 530' so it wili be an effective treatment technology.
Worksheet 2
Design Procedure Form for Native Planted Swale
Designer: Sharon L. Humphreys
Company: Bureau Veritas
Date: 8/16/2006
Project; Ei Camino Real Widening Project - Between Tamarack and Chestnut. Carisbad, CA
Location Subbasin F
1. Determine Design Fiow
(Use Worksheet 1) QBMP -
i -
0.198 cfs
100 %
2. Swale Geometry
a. Swale Bottom Width (b)
b. Side slope (z)
c. Flow direction slope (s) W N O" II II II 1.5 ft
3
2.5 %
3. Design fiow velocity (Manning n = 0.25) V -0.32 ft/s
4. Depth of flow (D) D = 0.27 ft
5. Design Length (L)
L = (10 min) x (fiow velocity, ft/sec) x (60 sec/min) L = 192.0 ft
6. Vegetation (describe)
Any fine, close-growing, water-resistant
grass approved by the City.
7. Ouflow Collection (check type used or describe "other")
L = (10 min) x (fiow velocity, ft/sec) x (60 sec/min) Grated inlet
Infiltration Trench
Underdrain
X Other Curb inlet
Notes:
Length available for native planted swale is 530' so it will be an effective treatment technology.
Worksheet 2
Design Procedure Form for Native Planted Swale
Designer: Sharon I. Humphreys
Company: Bureau Veritas
Date: 8/16/2006
Project: El Camino Real Widening Project - Between Tamarack and Chestnut. Carisbad, CA
Location Subbasin G
1. Determine Design Flow
(Use Worksheet 1) QBMP -
i =
0.144 cfs
100 %
2. Swale Geometry
a. Swale Bottom Width (b)
b. Side slope (z)
c. Flow direction slope (s)
1.5 ft
3
2.5 %
3. Design flow velocity (Manning n = 0.25) V = 0.29 ft/s
4. Depth of flow (D) D = 0.23 ft
5. Design Length (L)
L = (10 min) x (flow velocity, ft/sec) x (60 sec/min) 1= 174.0 ft
6. Vegetation (describe)
Any fine, close-growing, water-resistant
grass approved by the City.
7. Ouflow Collection (check type used or describe "other")
L = (10 min) x (fiow velocity, ft/sec) x (60 sec/min) Grated Inlet
Infiltration Trench
Underdrain
X other Curb Inlet
Notes:
Length available for native planted swale is 470' so it will be an effective treatment technology.
Worksheet 2
Design Procedure Form for Native Planted Swale
Designer: Sharon L. Humphreys
Company: Bureau Veritas
Date: 8/16/2006
Project: El Camino Real Widening Project - Between Tamarack and Chestnut. Carisbad, CA
Location Subbasin H
1. Determine Design Flow
(Use Worksheet 1) QBMP -
i -
0.144 cfs
100 %
2. Swale Geometry
a. Swale Bottom Width (b)
b. Side slope (z)
c. Flow direction slope (s)
1.5 ft
3
2.5 %
3. Design flow velocity (Manning n = 0.25) v -0.29 ft/s
4. Depth of fiow (D) D = 0.23 ft
5. Design Length (I)
L = (10 min) x (flow velocity, ft/sec) x (60 sec/min) 1= 174.0 ft
6. Vegetation (describe)
Any fine, close-growing, water-resistant
grass approved by the City.
7. Ouflow Collection (check type used or describe "other")
L = (10 min) x (fiow velocity, ft/sec) x (60 sec/min) Grated Inlet
Infiltration Trench
Underdrain
X other Curb Inlet
Notes:
Length available for native planted swale is 470' so it will be an effective treatment technology.
Worksheet 2
Design Procedure Form for Native Planted Swale
Designer: Sharon L. Humphreys
Company: Bureau Veritas
Date: 8/16/2006
Project: El Camino Real Widening Project - Between Tamarack and Chestnut. Carisbad, CA
Location Subbasin I
1. Determine Design Flow
(Use Worksheet 1) QBMP -
j _
0.108 Cfs
100 %
2. Swale Geometry
a. Swale Bottom Width (b)
b. Side slope (z)
c. Flow direction slope (s)
1.5 ft
3
2.5 %
3. Design flow velocity (Manning n = 0.25) V = 0.26 ft/s
4. Depth of fiow (D) D = 0.20 ft
5. Design Length (L)
L = (10 min) x (fiow velocity, ft/sec) x (60 sec/min) L = 156.0 ft
6. Vegetation (describe)
Any fine, close-growing, water-resistant
grass approved by the City.
7. Ouflow Collection (check type used or describe "other")
L = (10 min) x (fiow velocity, ft/sec) x (60 sec/min) Grated Inlet
infiltration Trench
Underdrain
X other Curb inlet
Notes:
length available for native planted swale is 835' so it will be an effective treatment technology.
Worksheet 2
Design Procedure Form for Native Planted Swale
Designer: Sharon I. Humphreys
Company: Bureau Veritas
Date: 8/16/2006
Project: El Camino Real Widening Project - Between Tamarack and Chestnut. Carisbad, CA
Location Subbasin J
1. Determine Design Flow
(Use Woritsheetl) QBMP -
i -
0.108 cfs
100 %
2. Swale Geometry
a. Swale Bottom Width (b)
b. Side slope (z)
c. Fiow direction slope (s)
1.5 ft
3
2.5 %
3. Design fiow velocity (Manning n = 0.25) V -0.26 ft/s
4. Depth of fiow (D) D = 0.20 ft
5. Design Length (L)
L = (10 min) x (fiow velocity, ft/sec) x (60 sec/min) L= 156.0 ft
6. Vegetation (describe)
Any fine, close-growing, water-resistant
grass approved by the City.
7. Ouflow Collection (check type used or describe "other")
L = (10 min) x (fiow velocity, ft/sec) x (60 sec/min) Grated Inlet
Infiltration Trench
Underdrain
X Other Curb inlet
Notes: Length available for native planted swale is 835' so it will be an effective treatment technology.
Worksheet 2
Design Procedure Form for Native Planted Swale
Designer: Sharon I. Humphreys
Company: Bureau Veritas
Date: 8/16/2006
Project: Ei Camino Real Widening Project - Between Tamarack and Chestnut. Carisbad, CA
Location Subbasin K
1. Determine Design Flow
(Use Worksheet 1) QBMP -
i -
0.207 cfs
100 %
2. Swale Geometry
a. Swale Bottom Width (b)
b. Side slope (z)
c. Flow direction slope (s)
1.5 ft
3
2.5 %
3. Design fiow velocity (Manning n = 0.25) V = 0.32 ft/s
4. Depth of fiow (D) D = 0.28 ft
5. Design Length (L)
L = (10 min) x (fiow velocity, ft/sec) x (60 sec/min) L= 192.0 ft
6. Vegetation (describe)
Any fine, close-growing, water-resistant
grass approved by the City.
7. Ouflow Collection (check type used or describe "other")
L = (10 min) x (flow velocity, ft/sec) x (60 sec/min) Grated Inlet
Infiltration Trench
Underdrain
X Other Curb Inlet
Notes:
length available for native planted swale is 320' so it will be an effective treatment technology.
Worksheet 2
Design Procedure Form for Native Planted Swale
Designer: Sharon L. Humphreys
Company: Bureau Veritas
Date: 8/16/2006
Project: Ei Camino Real Widening Project - Between Tamarack and Chestnut. Carisbad, CA
Location Subbasin L
1. Determine Design Fiow
(Use Worksheet 1) QBMP -
i =
0.207 cfs
100 %
2. Swale Geometry
a. Swale Bottom Width (b)
b. Side slope (z)
c. Flow direction slope (s)
1.5 ft
3
2.5 %
3. Design fiow velocity (Manning n = 0.25) V = 0.32 ft/s
4. Depth of flow (D) D = 0.28 ft
5. Design Length (L)
L = (10 min) x (fiow velocity, ft/sec) x (60 sec/min) L= 192.0 ft
6. Vegetation (describe) Any fine, close-growing, water-resistant
grass approved by the City.
7. Ouflow Collection (check type used or describe "other")
L = (10 min) x (flow velocity, ft/sec) x (60 sec/min) Grated inlet
Infiltration Trench
Underdrain
X Other Curb Inlet
Notes; Length available for native planted swale is 320' so it will be an effective treatment technology.
n
n
n
n
n
I
I
D
C
I
c
I
I
I
u
I
u
APPENDIX D
BMP FACT SHEETS
Vegetated Swale TC-30
Design Considerations
• Tributary Area
• Area Required
• Slope
• Water Availability
BES^ ORiGSN.
Description
Vegetated swales are open, shallow channels with vegetation
covering the side slopes and bottom that collect and slowly
convey innoff flow to downstream discharge points. They are
designed to treat runoff through filtering by the vegetation in the
channel, filtering through a subsoil matrix, and/or infiltration
into the underlying soils. Swales can be natural or manmade.
They trap particulate pollutants (suspended soHds and trace
metals), promote infiltration, and reduce the flow velocity of
stormwater runoff. Vegetated swales can serve as part of a
stormwater drainage system and can replace curbs, gutters and
storm sewer systems.
California Experience
Caltrans constructed and monitored six vegetated swales in
southern Cahfomia. These swales were generally effective in
reducing the volume and mass of pollutants in runoff. Even in
the areas where the annual rainfall was only about lo inches /yr,
the vegetation did not require additional irrigation. One factor
that strongly affected performance was the presence of large
numbers of gophers at most of the sites. The gophers created
earthen mounds, destroyed vegetation, and generally reduced the
effectiveness of the controls for TSS reduction.
Advantages
• If properly designed, vegetated, and operated, swales can
serve as an aesthetic, potentially inexpensive urban
development or roadway drainage conveyance measure with
significant collateral water quality benefits.
Targeted Constituents
0 Sedimenl A
0 Nutnenis •
0 Trash •
0 Metals A
0 Bacteria •
0 Oil and Grease A
0 Organics A
Legend (Removal Effectiveness)
• Low • Higti
A Medium
January 2003 California Stormwater BMP Handbook
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TC-30 Vegetated Swale
• Roadside ditches should be regarded as significant potential swale/buffer strip sites and
should be utilized for this purpose whenever possible.
Limitations
• Can be difficult to avoid channelization.
• May not be appropriate for industrial sites or locations where spills may occur
• Grassed swales cannot treat a very large drainage area. Large areas may be divided and
treated using multiple swales.
• Athick vegetative cover is needed for these practices to function properly.
• They are impractical in areas with steep topography.
• They are not effective and may even erode when flow velocities are high, if the grass cover is
not properly maintained.
• In some places, their use is restricted by law: many local municipalities require curb and
gutter systems in residential areas.
• Swales are mores susceptible to failure if not properly maintained than other treatment
BlVIPs.
Design and Sizing Guidelines
• Flow rate based design determined by local requirements or sized so that 85% of the annual
runoff volume is disdiaiged at less than the design rainfall intensity.
• Swale should be designed so that the water level does not exceed 2/3rds the height of the
grass or 4 inches, which ever is less, at the design treatment rate.
• Longitudinal slopes should not exceed 2.5%
• Trapezoidal channels are normally recommended but other configurations, such as
parabolic, can also provide substantial water quality improvement and may be easier to mow
than designs with sharp breaks in slope.
• Swales constructed in cut are preferred, or in fill areas that are far enough from an adjacent
slope to minimize the potential for gopher damage. Do not use side slopes constructed of
fill, which are prone to structural damage by gophers and other biHTOwing animals.
• A diverse selection of low growing, plants that thrive under the specific site, climatic, and
watering conditions should be specified. Vegetation whose growing season corresponds to
the wet season are preferred. Drought tolerant vegetation should be considered especially
for swales that are not part of a regularly irrigated landscaped area.
• The width of the swale should be determined using Manning's Equation using a value of
0.25 for Manning's n.
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Vegetated Swale TC-30
Construction/Inspection Considerations
• Include directions in the specifications for use of appropriate fertiHzer and soil amendments
based on soil properties determined through testing and compared to the needs of the
vegetation requirements.
• Install swales at the time of the year when there is a reasonable chance of successful
establishment without irrigation; however, it is recognized that rainfall in a ^ven year may
not be sufficient and temporary irrigation may be used.
• If sod tiles must be used, they should be placed so tiiat there are no gaps between the tiles;
stagger the ends of the tiles to prevent the formation of channels along the swale or strip.
• Use a roller on the sod to ensure that no air pockets form between the sod and the soil.
• Where seeds are used, erosion controls wiU be necessary to protect seeds for at least 75 days
after the first rainfall of tlie season.
Performance
The literature suggests that vegetated swales represent a practical and potentially effective
technique for controUing urban runoff quality. While limited quantitative performance data
exists for vegetated swales, it is known that check dams, slight slopes, permeable soils, dense
grass cover, increased contact time, and small storm events all contribute to successful pollutant
removal by the swale system. Factors decreasing the effectiveness of swales include compacted
soils, short runoff contact time, large storm events, frozen ground, short grass heights, steep
slopes, and high runoff velocities and discharge rates.
Conventional vegetated swale designs have achieved mixed results in removing particulate
pollutants. A study performed by the Nationwide Urban Runoff Program (NURP) monitored
three grass swales in the Washington, D.C., area and found no significant improvement in urban
runoff quality for the pollutants analyzed. However, the weak performance of these swales was
attributed to the high flow velocities in the swales, soil compaction, steep slopes, and short grass
height.
Another project in Durham, NC, monitored the performance of a carefully designed artificial
swale that received runoff from a commercial parking lot. The project tracked 11 storms and
concluded that particulate concentrations of heavy metals (Cu, Pb, Zn, and Cd) were reduced by
approximately 50 percent. However, the swale proved largely ineffective for removing soluble
nutrients.
The effectiveness of vegetated swales can be enhanced by adding check dams at approximately
17 meter (50 foot) increments along their length (See Figure 1). These dams maximize the
retention time within the swale, decrease flow velocities, and promote particulate settling.
Finally, the incorporation of vegetated filter strips parallel to the top of the channel banks can
help to treat sheet flows entering the swale.
Only 9 studies have been conducted on all grassed channels designed for water quality (Table 1).
The data suggest relatively high removal rates for some pollutants, but negative removals for
some bacteria, andfair performance for phosphorus.
January 2003 California Stormwater BfviP Handbook 3 of 13
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TC-30 Vegetated Swale
Table 1 Grassed swale pollutant removal efficiency data
Removal Efficiencies (% Removal)
Study TSS TP TN NO3 Metals Bacteria Type
Caltrans 2002 77 8 67 66 83-90 -33 dry swales
Gkildberg 1993 67.8 4.5 -314 42-62 -100 grassed channel
Seattle Metro and Washington
Department of Ecology 1992 60 45 --25 2-16 -25 grassed channel
Seattle Metro and Washington
Department of Ecology, 1992 83 29 --25 46-73 -25 grassed channel
Wang etal., 1981 80 ---70-80 -dry swale
Dorman et al., 1989 98 18 -45 37-81 -diy swale
Harper, 1988 87 83 84 80 88-90 -dry swale
Kercher et al., 1983 99 99 99 99 99 dry swale
Harper, 1988. 81 17 40 52 37-69 -wet swale
Koon, 199s 67 39 -9 -35 to 6 -wet swale
While it is difficult to distinguish between different designs based on the small amount of
available data, grassed channels generally have poorer removal rates than wet and dry swales,
although some swales appear to export soluble phosphorus (Harper, 1988; Koon, 19'95). It is not
clear why swales exportbacteria. One explanation is that bacteria thrive in the warm swale
soils.
Siting Criteria
The suitability of a swale at a site wiU depend on land use, size of the area serviced, soil type,
slope, imperviousness of the contributing watershed, and dimensions and slope of the swale
system (Schueler et al., 1992). In general, swales can be used to serve areas of less than 10 acres,
with slopes no greater than 5 %. Use of natural topographic lows is encouraged and natural
drainage courses should be regarded as significant local resources to be kept in use (Young et al.,
1996).
Selection Criteria (NCTCOG, 1993)
m Comparable performance to wet basins
• Limited to treating a few acres
• Availabflity of water during dry periods to maintain vegetation
• Sufficient available land area
Research in the Austin area indicates that vegetated controls are effective at removing pollutants
even when dormant. Therefore, irrigation is not required to maintain growth during dry
periods, but may be necessary only to prevent the vegetation from dying.
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January 2003
Vegetated Swale TC-30
The topography of the site should permit the design of a channel with appropriate slope and
cross-sectional area. Site topography may also dictate a needfor additional structural controls.
Recommendations for longitudinal slopes range between 2 and 6 percent. Flatter slopes can be
used, if sufficient to provide adequate conveyance. Steep slopes increase flow velocity, decrease
detention time, and may require energy dissipating and grade check Steep slopes also can be
managed using a series of check dams to terrace the swale and reduce the slope to within
acceptable limits. The use of check dams with swales also promotes infiltration.
Additional Design Guidelines
Most of the design guidelines adopted for swale design specify a minimum hydraulic residence
time of 9 minutes. This criterion is based on the results of a single study conducted in Seattie,
Washington (Seattle Metro andWashingtonDepartment of Ecology, 1992), and is not well
supported. Analysis of the data collected in that study indicates tliat pollutant removal at a
residence time of 5 minutes was not significanfly different, although there is more variability in
that data. Therefore, additional research in the design criteria for swales is needed. Substantial
pollutant removal has also been observed for vegetated controls designed solely for conveyance
(Barrett et al, 1998); consequentiy, some flexibility in the design is warranted.
Many design guidelines recommend that grass be frequentiy mowed to maintain dense coverage
near the gromd surface. RecentresearchCColwellet al., 2000) has shown mowing frequency or
grass height has Htfle or no effect on poUutant removal.
Summary of Design Recommendations
1) The swale should have a length that provides a minimum hydraulic residence time of
at least 10 minutes. The maximum bottom width should not exceed 10 feet unless a
dividing berm is provided. The depth of flow should not exceed 2/3rds the height of
the grass at the peak of the water quality design storm intensity. The channel slope
shouldnot exceed 2.5%.
2) A desi^ grass height of 6 inches is recommended.
3) Regardless of the recommended detention time, the swale should be not less than
100 feet in length.
4) The width of the swale should be determined using Manning's Equation, at the peak
of tlie design storm, using a Mannings n of 0.25.
5) The swale canbe sized as botha treatment facility for the design storm and as a
conveyance system to pass the peak hydraulic flows of the 100-year storm if it is
located "on-line." The side slopes shouldbe no steeper than 3:1 (H:V).
6) Roadside ditches should be regarded as significant potential swale/buffer strip sites
and should be utilized for this purpose whenever possible. If flow is to be introduced
through curb cuts, place pavement sHghtiy above the elevation of the vegetated areas.
Curb cuts should be at least 12 inches wide to prevent clogging.
7) Swales must be vegetated in order to provide adequate treatment of runoff. It is
important to maximize water contact with vegetation and the soil surface. For
general purposes, selectfine, close-growing, water-resistant grasses. If possible,
divert runoff (other than necessary irrigation) during the period of vegetation
January 2003 California Stormwater BMP Handbook 5 of 13
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TC-30 Vegetated Swale
establishment. Where runoff diversion is not possible, cover graded and seeded
areas with suitable erosion control materials.
Maintenance
The useful life of a vegetated swale system is directly proportional to its maintenance frequency.
If properiy designed and regularly maintained, vegetated swales can last indefinitely. The
maintenance obj ectives for vegetated swale systems include keeping up the hydraulic and
removal efficiency ofthe channel and maintaining a dense, healthy grass cover.
Maintenance activities should include periodic mowing (with grass never cut shorter than the
designfiow depth), weed control, watering during drougjit conditions, reseeding of bare areas,
and clearing of debris and blockages. Cuttings should be removed from the channel and
disposed in a local composting facility. Accumulated sediment should also be removed
manually to avoid concentrated flows in the swale. The application of fertilizers and pesticides
should be minimal.
Another aspect of a good maintenance plan is repairing damaged areas within a channel. For
example, if the channel develops ruts or holes, it should be repaired utUizing a suitable soil that
is properly tamped and seeded The grass cover should be tliick; if it is not, reseed as necessary.
Any standing water removed during the maintenance operation must be disposed to a sanitary
sewer at an approved discharge location. Residuals (e.g., silt, grass cuttings) must be disposed
in accordance with local or State requirements. Maintenance of grassed swales mostiy involves
maintenance ofthe grass or wetland plant cover. Typical maintenance activities are
summarized below
• Inspect swales at least twice annually for erosion, damage to vegetation, and sediment and
debris accumulation preferably at the end of the wet season to schedule summer
maintenance and before maj or fall runoff to be sure the swale is ready for winter. However,
additional inspection after periods of heavy runoff is desirable. The swale should be checked
for debris and litter, and areas of sediment accumulation.
• Grass height and mowing fi-equency may not have a large impact on pollutant removal.
Consequentiy, mowing may only be necessary once or twice a year for safety or aesthetics or
to suppress weeds and woody vegetation.
• Trash tends to accumulate in swale areas, particularly along highways. The need for litter
removal is determined through periodic inspection, but litter should always be removed
prior to mowing.
• Sediment accumulating near culverts and in channels should be removed when it builds up
to 75 mm (3 in.) at any spot, or covers vegetation.
• Regularly inspect swales for pools of standing water. Swales can become a nuisance due to
mosquito breeding in standing water if obstructions develop (e.g. debris accumulation,
invasive vegetation) and/or if proper drainage slopes are not implemented and maintained.
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Vegetated Swale TC-30
Cost
Construction Cost
littie data is available to estimate the difference in cost between various swale designs. One
study (SWRPC, 1991) estimated the construction cost of grassed channels at approximately
$0.25 per ft^. This price does not include design costs or conttngendes. Brown and Schueler
(1997) estimate these costs at approximately 32 percent of construction costs for most
stormwater management practices. For swales, however, these costs would probably be
significanfly higher since the construction costs are so low compared with other practices. A
more realistic estimate would be a total cost of approximately $0.50 perfp, which compares
favorably with other stormwater management practices.
January 2003 California Stormwater BMP Hancboc^< 7 of 13
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TC-30 Vegetated Swale
Table 2 Swale Cost Estimate (SEWRPC, 1991)
Unit Cost Totai Cost
Component Unit Extent Low Moderate High Low Moderate High
Mabiiization /
Damobi llzation -Li g ht
Swaie 1 SI 07 1274 $441 $107 $274 $441
Site Preparation
Clearing"
Grubbing^.
Goners i
Excavatiorf'
l-avsl and Till"
Acre
Acre
0,5
0.25
372
1,210
$2,200
$3,dQ0
$2 10
$0 20
$3,600
$5,20Q
$3.70
$0.35
$5,400
$e,eoo
3S.30
^.50
$1,100
$950
$781
$242
$1,900
$1,300
$1,378
$424
$2,700
$1.B50
$1,872
$605
SilQS DGVBlopmonI
SaivBOBd Topsoii
SBBO, and Mulch'..
Sads
Yd=
Yd"
1,210
1,210
$0.40
$1.20
$1.Q0
SZ.4Q
$1 GO
S3.eo
$4&4
S 1,452
$1,210
$2,904
$1,936
$4,356
Subtotal ------$5,11B $g,3BB $13,660
CortingflncleB Swaie 1 26% 25% 26% $1,279 $2,347 $3,415
Total -----$6 3B5 $11,735 $17,075
Saurca: (SEWRPC, 1SS1)
Note: Mclbliizatlantiemobllization rsfers to \hQarssn\7st\on snd planning Inwlved in establistiing a vegetative Bwale.
' Swale has s bottom width of 1,0 foot, atop width of 10 feet with 1:3 side slopes, and a I.ODO-foot length.
''Areacleared = (top width +10 teet} xswaie length.
"Area grubbed = [topwidth x swale length).
"Volume excavated = (0.67x top widthx swale depth) x swale length tparabollc cross-section).
•Area tilled = (lop width t B(swaledepth^x sv;ale length (parabailc cross-section).
3(top width)
' Area seeded = erea cleared KO.5.
' Area sodded - area cleared x 0,5.
8 of 13 California Stormwater BMP Handbook
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January 2003
Vegetated Swale TC-30
Table 3 Estimated Maintenance Costs fSEWRPC, 19911
Swale Size
(Depth and Top Width)
Component Unit Cost 1.5 Fool Depth, One-
Foot Bottom Width,
lO.FootTop Width
3-Foot Depth, 3-Foot
Bottom Width, 21-Foot
Top Width
Comment
i-awn IVIowiiig $0.85/1,000 ft^/mcTwrg SO.U/linasrfoot $0.21 /iinearfoot Lawn maintenanoe area-tlDp
width + 10fost]K length. Mow
eigtit times par year
Ganersi Lavm Gare $9.00/1,000 ff/year $0.16/tin earfoDt $0.29 / linear foDl Lawn meintsnanw area •> (top
widlln ••• 10 feai} u longlti
Swaie Dsbris and Litter
Ramcval
$0.10'linearfxd/year $0.10/tin earfoDt $0.10/ii near foot -
Grass Resoeding with
Mulch and Fertiii^r
$0 30/yd' $001 /tinesrfoot $0.01 / linear foot Area mtiegetated equals 1%
cf iflwn maintenancearsa per
year
ProBram Administration and
Swaie inspection
$015/ linear fbct / year,
plus £25/ inspeclion
$0.1S /iinosrfoot $0.15 / ii near foot inspect tour times per year
Totaf -t0.5a/lln«arroo1 ${}.?£/linav foot -
January 2003 California Stormwater BMP Handbook
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9 of 13
TC-30 Vegetated Swale
Maintenance Cost
Caltrans (2002) estimated the expected annual maintenance costfor aswale withatributaiy
area of approximately 2 ha at approximately $2,700. Since almost aU maintenance consists of
mowing the cost is fundamentally a function of the mowing frequency. Unit costs developed by
SEWRPC are shown in Table 3. In many cases vegetated channels would be used to convey
runoff and would require periodic mowing as well, so there may be Kttie additional cost for the
water quality component Since essentially all the activities are related to vegetation
management, no special training is required for maintenance personnel.
References and Sources of Additional Information
Barrett, Michael E., Walsh, Patrick M., Mahna, Joseph F., Jr., Charbeneau, Randall J, 1998,
"Performance of vegetative controls for treating highway runoff," ASCE Journal of
Environmental Engineering^ Vol. 124, No. 11, pp. 1121-1128.
Brown, W., andT. Schueler 1997. The Economics of Stormwater BMPs in the Mid-Atlantic
Region. Prepared for the Chesapeake Research Consortium, Edgewater, MD, by the Center for
Watershed Protection, EUicott City, MD.
Center for Watershed Protection (CWP). 1996. Design of Stormwater Filtering Systems.
Prepared for the Chesapeake Research Consortium, Solomons, MD, and USEPA Region V,
Chicago, IL, by the Center for Watershed Protection, EUicott City, MD.
ColweU, Shanti R., Homer, Richard R., and Booth, Derek B., 2000. Characterization of
Performance Predictors andEvaluation of Mowing Practices in Biofiltration Swales. Report
to ^ng County Land And Water Resources Division and others by Center for Urban Water
Resources Management, Department of Civil and Environmental Engineering, University of
Washington, Seattie, WA
Dorman, M.E., J. Hartigan, R.F. Steg, and T. Quasebarth. 1989. Retention, Detention and
OverlandFlow for Pollutant Removal From Highway Stormwater Runoff. Vol. 1. FHWA/RD
89/202. Federal Highway Administration, Washington, DC.
Goldberg. 1993. Dayton Avenue Swale Biofiltration Study. Seattie Engineering Department,
Seattie, WA.
Harper, H. 1988. Effects of Stormwater Management Systems on Groundwater Quality.
Prepared for Florida Department of Environmental Regulation, Tallahassee, FL, by
Environmental Research and Design, Inc., Orlando, FL.
Kercher, W.C., J.C. Landon, and R. MassarelU. 1983. Grassy swales prove cost-effective for
water poEution control. Public Works, 16: 53-55.
Koon, J. 1995. Evaluation of Water Quality Ponds and Swales in the Issaquah/East Lake
Sammamish Basins. King County Surface Water Management, Seattie, WA, and Washington
Department of Ecology, Olympia, WA
Metzger, M. E., D. F. Messer, C. L. Beitia, C. M. Myers, and V. L. Kramer. 2002. The Dark Side
Of Stormwater Runoff Management: Disease Vectors Associated With Structural BMPs.
Stormwater 3(2): 24-39.0akland, P.H. 1983. An evaluation of stormwater pollutant removal
10 of 13 California Stormwater BMP Handbook January 2003
New Development and Redevelopment
www.cabmphandbooks.com
Vegetated Swale TC-30
through grassed swale treatment. In Proceedings of the International Symposium of Urban
Hydrology, Hydraulics and Sediment Control, Lexington, KY. pp. 173-182.
Occoquan Watershed Monitoring Laboratory. 1983. Final Report Metropolitan Washington
Urban Runoff Project. Prepared for the Metropolitan Washington Council of Governments,
Washington, DC, by the Occoquan Watershed Monitoring Laboratory, Manassas, VA
Pitt, R., and J. McLean. 1986. Toronto Area Watershed Management Strategy Study: Humber
River Pilot Watershed Project. Ontario Ministry of Environment, Toronto, ON.
Schueler, T. 1997. Comparative Pollutant Removal Capabihty of Urban BMPs: A reanalysis.
Watershed Protection Techniques 2(2):379-383.
Seattie Metro and Washington Department of Ecology. 1992. Biofiltration Swale Performance:
Recommendations and Design Considerations. Publication No. 657. Water Pollution Control
Department, Seattie, WA
Southeastern Wisconsin Regional Planning Commission (SWRPC). 1991. Costs of Urban
Nonpoint Source Water Pollution Control Measures. Technical report no. 31. Southeastern
Wisconsin Regional Planning Commission, Waukesha, WI.
U.S. EPA, 1999, Stormwater Fact Sheet Vegetated Swales, Report # 832-F-99-006
http: //www.epa.gov/owm/mtb /vegswale.pdf. Office of Water, Washington DC.
Wang, T., D. Spyridakis, B. Mar, and R. Homer. 1981. Transport, Deposition andControl of
Heavy Metals in Highway Runoff. FHWA-WA-RD-39-10. University of Washington,
Department of CivQ Engineering, Seattie, WA
Washington State Department of Transportation, 1995, Highway Runoff Manual, Washington
State Department of Transportation, Olympia, Washington.
Welbom, C, andJ. Veenhuis. 1987. Effects of Runoff Controb on the Quantity andQuality of
Urban Runoff in Two Locations in Austin, IX. USGS Water Resources Investigations Report
No. 87-4004. U.S. Geological Survey, Reston, VA.
Yousef, Y., M. WanieHsta, H. Harper, D. Pearce, andR. Tolbert 1985. Best Management
Practices: Removal of Highway Contaminants By Roadside Swales. University of Central
Florida and Florida Department of Transportation, Orlando, FL.
Yu, S., S. Barnes, and V. Gerde. 1993. Testing of Best Management Practices for Controlling
Highway Runoff. FHWA/VA-93-R16. Virginia Transportation Research Coundl,
Charlottesville, VA
Ijiformation Resources
MarylandDepartment of the Environment (MDE). 2000. Maryland Stormwater Design
Manual, www.mde.state.md.us/environment/wma/stormwatermanual. Accessed May 22,
2001.
Reeves, E. 1994. Performance and Condition of Biofilters in the Pacific Northwest. Watershed
Protection Techniques 1(3): 117-119.
January 2003 California Stormwater BMP Hancbook 11 of 13
New Development and Redevelopment
www,cabmplnandbooks.com
TC-30 Vegetated Swale
Seattie Metro and Washington Department of Ecology. 1992. Biofiltration Swale Performance.
Recommendations and Design Considerations. Publication No. 657. Seattie Metro and
Washington Department of Ecology, Olympia, WA
USEPA 1993. Guidance Specifying Management Measures for Sources ofNonpoint Pollution in
Coastal Waters. EPA-840-B-92-002. U.S. Environmental Protection Agency, Office of Water.
Washington, DC.
Watershed Management Institute (WMI). 1997. Operation, Maintenance, and Management of
Stormwater Management Systems. Preparedfor U.S. Environmental Protection Agency, Office
of Water. Washington, DC, by the Watershed Management Institute, Ingleside, MD.
12 of 13 California Stormwater BMP Handbook January 2003
New Development and Redevelopment
www. cabmplnandbooks, com
Vegetated Swale TC-30
Provide for scour
pfoieclion.
Crasi iixtiaii ofswafc with check dam.
Notation:
L : Length of tvitsia tmpountiincnl ana per chseJs dam itQ {b) Dg = Depth «t ch«ck dam (f^
Ss = Bottom slpe<ri swale (ftTQ W = Top wldtti or Chech dam Eft)
WB =eottomwidth ofchwltdamift)
Z]j] E Raflo ot horfiontal to vertic*! ciiange in swais side ^ofn (ft/ft)
»lBstiisioBal view of swale lmi>oiiiidim«»t area.
January 2003 California Stormwater BMP Hancbook
New Development and Redevelopment
www.cabmptiandbooks.ccm
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