HomeMy WebLinkAboutCT 04-04; La Costa Ridge Neighborhood 2.5; Storm Water Management Plan; 2005-06-30HUNSAKER
^ASSOCIATES
SAN DIECO, INC.
PLANNING
ENGINEERING
SURVEYING
IRVINE
LOS ANGELES
RIVERSIDE
SAN DIEGO
STORM WATER
MANAGEMENT PLAN
for
LA COSTA RIDGE
NEIGHBORHOODS 2.5
City of Carlsbad, California
Prepared for:
Real Estate Collateral Management Company
c/o Morrow Development
1903 Wright Place, Suite 180
Carlsbad, CA 92008
w.o. 2352-93
June 30, 2005
DAVE HAMMAR
LEX WILLIMAN
ALISA VIALPANDO
DAN SMITH
RAY MARTIN
10179 Huennekens St.
San Diego, CA 92121
(858) 558-4500 PH
(858)558-1414 FX
www.HunsakerSD.com
lnfo@HunsakerSD.com
Eric Mosolgo, R.C.E.'
Water Resources Department Manager
Hunsaker & Associates San Dlego, Inc.
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La Costa Ridge - Neighborhood 2.5
Storm Water Management Plan
TABLE OF CONTENTS
CHAPTER 1 - Executive Sumnnary
1.1 Introduction
1.2 Summary of Pre-Developed Conditions
1.3 Summary of Proposed Development
1.4 Results and Recommendations
1.5 Conclusion
CHAPTER 2 - Storm Water Criteria
2.1 Regional Water Quality Control Board Criteria
2.2 City of Carlsbad SUSMP Criteria
CHAPTER 3 - Identification of Typical Pollutants
3.1 Anticipated Pollutants from Project Site
3.2 Sediment
3.3 Nutrients
3.4 Trash & Debris
3.5 Oxygen-Demanding Substances
3.6 Oil & Grease
3.7 Bacteria and Viruses
3.8 Pesticides
CHAPTER 4 - Conditions of Concern
4.1 Receiving Watershed Descriptions
4.2 Pollutants of Concern in Receiving Watersheds
CHAPTER 5 - Flow-Based BMPs
5.1 Design Criteria
5.2 Vortechs Treatment Units
5.3 Pollutant Removal Efficiency
5.4 Maintenance Requirements
5.5 Operations and Maintenance Plan
5.6 Schedule of Maintenance Activities
5.7 Annual Operations & Maintenance Costs
CHAPTER 6 - Source Control BMPs
6.1 Landscaping
6.2 Urban Housekeeping
6.3 Automobile Use
6.4 Site Design
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La Costa Ridge - Neighborhood 2.5
Storm Water Management Plan
CHAPTER 7 - Treatment Control BMP Design (Vortechs Treatment Unit)
7.1 BMP Location
7.2 Determination of Treatment Flow
7.3 Vortechs Treatment Unit Selection
CHAPTER 8 - Fiscal Resources
8.1 Fiscal Mechanism Selection
8.2 Agreements (Mechanisms to Assure Maintenance)
CHAPTER 9 - References
BMP LOCATION EXHIBIT (pocket)
List of Tables and Figures
Chapter 1 - Watershed Map
Chapter 2 - Storm Water Requirements Applicability Checklist
Chapter 3 - Pollutant Category Table
Chapter 4 - Combined 1998 and Draft 2002 Section 303(d) Update
Chapter 4 - Beneficial Uses of Inland Surface Waters
Chapter 4 - Water Quality Objectives
Chapter 6 - Pollutant Removal Efficiency Table (Flow-Based BMPs)
Chapter 7 - 85"^ Percentile Rainfall Isopluvial Map
Chapter 7 - Design Runoff Determination Spreadsheets
Chapter 7 - Vortechs System Data
Chapter 8 - Maintenance Mechanism Selection Table
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Att: City Engineer
Re: Storm Water Management Comments
Dear Sir,
The following comments have been reviewed and addressed
accordingly in the following manner.
d) Establish specific procedures for handling spills and routine clean up.
Special considerations and effort shall be applied to resident education on
the proper procedures for handling clean up and disposal of pollutants.
The La Costa Ridge development is a single family residential project. There
will be no communal trash storage areas as found in multi family
developments, nor will there be commercial or industrial usage ofthe lots
(such usage is not zoned, or permitted). "Chapter 7 - Source Control BMPs"
outlines the requirements of residents ofthe La Costa Ridge development
and also the responsibility of the Master Homeowners Association to inform
these residents of activities which are unlawful - including storage and
handling of household chemicals and illegal discharge to storm drains etc.
Thus a spill is an unlikely scenario.
As such Chapter 7 - Source Control BMPs addresses this requirement.
e) Ensure long-term maintenance of all post construct BMPs in perpetuity.
"Chapter 5 - Flow-Based BMPs" includes sections 5.6 Schedule of
Maintenance Activities and also 5.7 Annual Operations & Maintenance Costs.
Within these sections, annual maintenance requirements and also
maintenance costs (and responsibility for these costs) have been included.
"Chapter 8 - Fiscal Resources" has been included within the updated
SWMP's to include the funding mechanism for the BMP units also.
f) Identify how post development runoff rates and velocities from the site will
not exceed the pre-developed runoff rates and velocities to the maximum
extent practicable.
These velocities and flows have been calculated in the "Mass Grading
Hydrology Study for La Costa Greens Neighborhoods 2.1 through 2.5", dated
January, 2004 by Hunsaker & Associates San Diego, Inc. This report has
been referenced within the SWMP.
La Costa Ridge - Neighborhood 2.5
Storm Water Management Plan
CHAPTER 1 - EXECUTIVE SUMMARY
1.1 - Introduction
The La Costa Ridge Neighborhood 2.5 project site is bisected by Corinthia Street,
South of Xana Way, east of La Costa Ridge Neighborhoods' 2.2 and 2.3 within the
City of Carlsbad, California (see vicinity map below).
Per the City of Carlsbad SUSMP, the La Costa Ridge Neighborhood 2.5 project is
classified as a Priority Project and subject to the City's Permanent Storm Water BMP
Requirements.
This Storm Water Management Plan (SWMP) has been prepared pursuant to
requirements set forth in the City of Carlsbad's "Standard Urban Storm Water
Mitigation Plan (SUSMP)." All calculations are consistent with criteria set forth by
the Regional Water Quality Control Board's Order No. 2001-01, and the City of
Carlsbad SUSMP.
This SWMP recommends the location and sizing of a single Best Management
Practice (BMP) treatment unit, which will treat 85*"^ percentile runoff priorto
discharging from the development site (see BMP Location Map in this chapter).
Furthermore, this report determines anticipated project pollutants, pollutants of
concern in the receiving watershed, recommended source control BMPs, and
methodology used forthe design of flow-based BMPs.
LA COSTA RIDGE 2.5 VICINITY MAP
PROJECT
SITE
CQRfNTlA STREET
MASTER TENTATIVE
MM> BOUNDARY
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La Costa Ridge - Neighborhood 2.5
Storm Water Management Plan
1.2 - Summarv of Pre-Developed Conditions
Located in the Batiquitos watershed, the 27-acre site consists of primarily
undisturbed terrain covered with natural vegetation with portions being mass-graded,
as shown on Drawing No. 397-3A. The project site is drained by San Marcos Creek,
which flows westerly just south ofthe site.
The existing condition hydrologic analysis ofthe La Costa Ridge Planning Area 2.5
development was completed and discussed in the "Mass Grading Hydrology Study
for Villages of La Costa Neighborhoods 2.1 through 2.5" prepared by Hunsaker &
Associates San Diego, Inc. and dated January 20, 2004.
The Regional Water Quality Control Board has identified San Marcos Creek as part
ofthe Carlsbad Hydrologic Unit, San Marcos Hydrologic Area, and the Batiquitos
Hydrologic Subarea (basin number 904.51).
1.3 - Summarv of Proposed Development
Development ofthe La Costa Ridge Neighborhood 2.5 site will include the
construction of 66 single-family homes as well as associated streets, sidewalks,
landscaping and utilities.
Two (2) flow-based BMP will be located at the two discharge iocations within
Neighborhood 2.5. The northern unit however services the adjacent La Costa Ridge
Neighborhood 2.1 and receives no tributary area from the Neighborhood 2.5 site.
Thus the southern unit receives all first flush runoff from the Neighborhood 2.5
development. For further information on the northern Neighborhood 2.1 flow based
treatment unit, refer to the "Storm Water Management Plan for La Costa Ridge
Neighborhoods' 2.1 & 2.2" by Hunsaker & Associates, March 2005.
The 85*"^ percentile runoff will be treated in the proposed Vortechs system within
Corinthia Street prior to discharging into the receiving drainage system.
1.4- Results and Recommendations
Table 1 below summarizes rational method 85^^ percentile calculations forthe
proposed water quality treatment unit for the La Costa Ridge Neighborhood 2.5
development.
Table 1 - Developed Conditions 85*^ Percentile Calculations
Treatment Unit
Location
Drainage
Area
(acres)
Rainfall
Intensity
(inches/hour)
Runoff
Coefficient
85'*^
Percentile
Flow (cfs)
Corinthia Street 69.4 0.2 0.42* 5.8
*=weighted C coefficient - See Chapter 7
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ARLSBAD
ENaJOITAS
WATERSHED MAP FOR
LA COSTA RIDGE
crrv OF CARLSBAD, CALIFORNIA
La Costa Ridge - Neighborhood 2.5
Storm Water Management Pian
Rational Method calculations predicted an 85*^ percentile runoff flow of
approximately 5.8 cfs for the proposed residential development.
A single Vortechs Model 9000 treatment unit (or an approved, equivalent flow
based treatment unit) with a treatment flow capacity of 14 cfs is recommended.
The proposed Vortechnics treatment unit (or an approved, equivalent flow based
treatment unit) will be an offline pre-cast treatment unit. The 85'^ percentile design
flow rate is forced into the treatment area by a diversion weir built in the upstream
junction. Flows in excess of the design flow rate pass over the weir and proceed
downstream.
1.5 - Conclusion
The combination of proposed construction and permanent BMP's will reduce, to the
maximum extent practicable, the expected project pollutants and will not adversely
impact the beneficial uses ofthe receiving waters.
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LEGEND
WATERSHED BOUNDARY -
WATER QUALITY UNIT o
if/J/Jift!!/
m? LOCATION EXHIBIT FOR
LA COSTA RIDGE
NEIGHBORHOOD 2.5
CITY OF CARLSBAD, CALIFORNIA
SHEET
1
OF
1
La Costa Ridge - Neighborhood 2.5
Storm Water Management Plan
CHAPTER 2 - STORM WATER CRITERIA
2.1 - Regional Water Qualitv Control Board Criteria
All runoff conveyed in the proposed storm drain systems will be treated in
compliance with Regional Water Quality Control Board regulations and NPDES
criteria prior to discharging to natural watercourses. California Regional Water
Quality Control Board Order No. 2001-01, dated February 21, 2001, sets waste
discharge requirements for discharges of urban runoff from municipal storm
separate drainage systems draining the watersheds of San Diego County.
Per the RWQCB Order, post-development runoff from a site shall not contain
pollutant loads which cause or contribute to an exceedance of receiving water
quality objectives or which have not been reduced to the maximum extent
practicable. Post-construction Best Management Practices (BMPs), which referto
specific storm water management techniques that are applied to manage
construction and post-construction site runoff and minimize erosion, include source
control - aimed at reducing the amount of sediment and other pollutants - and
treatment controls that keep soil and other pollutants onsite once they have been
loosened by storm water erosion.
Post construction pollutants are a result ofthe urban development ofthe property
and the effects of automobile use. Runoff from paved surfaces can contain both
sediment (in the form of silt and sand) as well as a variety of pollutants transported
by the sediment. Landscape activities by homeowners are an additional source of
sediment.
All structural BMPs shall be located to infiltrate, filter, or treat the required runoff
volume or flow (based on the 85*^^ percentile rainfall) prior to its discharge to any
receiving watercourse supporting beneficial uses.
2.2 - Citv of Carlsbad SUSMP Criteria
Per the City of Carlsbad SUSMP, the La Costa Ridge Neighborhood 2.5 project is
classified as a Priority Project and subject to the City's Permanent Storm Water BMP
Requirements. These requirements required the preparation ofthis Storm Water
Management Plan.
The Storm Water Applicability Checklist, which must be included along with Grading
Plan applications, is included on the following page.
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storm Water Standards
4/03/03
VI; RES0URCESL& REFERENCES: • •
APPENDIXA
STORM WATER REQUIREMENTS APPUCABILITY CHECKUST
Complete Sections 1 and 2 of the following checklist to determine your Droied's
pemianent and construction stomn water best management practices ^equireSs
This form must be completed and submitted with your permit application.
Section 1. Permanent Storm Water BMP Requirements:
^. any answers to Part A are answered -Yes." your project is subject to the Trioritv
Wat?RMS"r"^-^'°^^^^ Requirements,-and-Standard Pemianlnt StoS^ Water BMP Requirements" in Section III, "Pennanent Storni Water BMP Selection Procedure" in the Storm Wafer Standards manual. ^^eiection
If all answers to Part A are "No." and am^ answers to Part B are "Yes." your project is
only subject to the "Standard Pennanent Stonn Water BMP Requirements" If even/"
question in Part A and B is answered "No," your projfed is exempt from permanent
storni water requirements. " Hcuficjfiem
Part A: Detennine Prioritv Project Permanent Storm Water BMP Reauirements
Does the project meet the definitjon of one or more ofthe priority proiect
categories?* ^
1. Detached residential development of 10 or more units """
"J AH^^u^j —_!j J .— :—r-rz—^ .
Yea No
!. Attached residential development of 10 or more units
' Commercial development greaterthan 100,000 square feet
4. Automotive repair shop
5. Restaurant V
Steep hiliside development greaterthan 5,000 square feet
7. Proiect discharging to receivinq waters within Environmentally Sensitive Areas
a.. Paridng lots greater than or equal to 5,000 r or with at least 15 paridng spaces and
potentiallv exposed to uriaari runoff '
9. Streets, roads, highways, and freeways which would create a new paved surface that is 5,000 square feet or greater •
' f^f er^°5^e definitions section in the Storm Water Standards 1or expanded definitions of thi priority project categones.
Lirniied Exdustorr. Trenching and resuriacing worit assodated with utility projects are not considered
pnonty projects. Paridng lots, buildings and other structures associated with utility proiects are
priority projects if one cr more of the criteria in Part A is met If ali answers to Part A are "No"
contnue to Part B. '
•an
storm Water Standards
4/03/03
Part B; Determine Standard Permanent Storm Water Requirements.
Does the project propose: Yes No
1. New impervious areas, such as rooftops, roads, paridng lots, driveways, paths and
sidewalks?
2. MSW pSr.'iCuS IsridSCapa SrcSS and iiTiyStiOn ayStBlTlS?
3. Permanent structures within 100 feet cf any natural water body? y
4. Trash storage areas? y
5. Liquid or solid material loading and unloading areas?
6. Vehicle or equipment fueling, washing, or maintenance areas? y
7. Require a General NPDES Pennit far Stomi Water Discharges Assodated with
Industrial ActiviHes (Except construction)?* y
8. Commercial or Industriai waste handling or stooge, exduding typical office or
household waste? y
9. Any grading or gnaund disturibance during construction? y
10. Any new storm drains, or alteration to existing stonn drains? y *To find out if your prciject is required to obtain an individual General NPDES Pemiit for Storm Water
Discharges Assodated with Industrial Activities, visit the State Water Resources Control Board web site
at, www.swrcb.ca.gov/stormwtr/industrial.html
Section 2. Construction Storm Water BIWP Requirements:
If the answer to question 1 of Part C is answered "Yes," your project is subject to
Section IV, "Constmction Storm Water BMP Performance Standards," and must prepare
a Stonn Water Pollution Prevention Plan (SWPPP). Ifthe answer tq question 1 is "No,"
but the answer to any of the remaining questions is "Yes," your project is subject to
Section IV, "Construction Stomn Water BMP Perfonnance 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 stonn 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? Yfes No
1. Is the project subject to Califomia's statewide General NPDES Permit for Storm Water
Discharges Associated With Construction Activities? s/
2. Does the project propose grading or soil disturbance? y
3. Would storm water or urban runoff have the potential to contact any portion of the
construction area, including washing and staging areas? y
• 4. Would the project usa 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 -
PartD: Determine Construction Site Priority
In accordance witin the Municipal Pennit, each constmction site with constmction stomi
mier BMP requirements must be designated with a priority: high, medium or low
This prioritization must be completed witii tiiis fomn, noted on the plans, and included iri
the SWPPP or WPCP. Indicate the projecf s'priority in one of the check boxes
criteria below, and existing and surroundirig conditions of the project, the~ type "of
activities necessary to complete tiie constmction and any other extenuating
circumstances that may pose a threat ta water quality. The City reserves the right to
adjust tiie priority of tiie projects botii before and during constmction. [Note:
The constmction priority does NOT-change constuction BMP requirements tiiat apply
to projects; all constiuction BMP requirements must be identified on a case-by-case
basis. The constiuction priority does affect the frequency of inspections that will be
conducted by City staff. See Section 1V.1 for more details on constmction BMP-
requirements.]
A) High Priority
1) Projects where the site is 50 acres or more and grading will occur during the
rainy season
2) Projects 5 acres or more. 3) Projects 5 acres or more within or directiy
adjacent to or discharging directly to a coastal lagoon or other receiving water
within an environmentally sensitive area
Projects, active or inactive, adjacent or tiibutary to sensitive water bodies
• B) Medium Priority
1) Capital Improvement Projects where .grading occurs, however a Storm Water
Pollution Prevention Plan (SWPPP) is not required under the State General
Constmction Permit (i.e., water and sewer replacement projects, intersection
and street re-alignments, widening, comfort stations, etc.)
2) Pennit 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.
3) Pennit projects on private property where grading permits are required,
however. Notice Of Intents (NOIs) and SWPPPs are not required.
• C; Low Priority
1) Capital Projects where minimal to no grading occurs, such as signal light and
loop installations, street light installations, etc.
2) Pennit pnDjects in Uie public right-of-way where minimal to no grading occurs,
such as pedestrian ramps, driveway additions, small retaining walls, etc.
3) Pennit projects on private property where grading permits are not required,
such . as small retaining walls,, single-family homes, small tenant
improvements, etc.
32
La Costa Ridge - Neighborhood 2.5
Storm Water Management Pian
CHAPTER 3 - IDENTIFICATION OF TYPICAL POLLUTANTS
3.1 - Anticipated Pollutants from Proiect Site
The following table details typical anticipated and potential pollutants generated by
various land use types. The La Costa Ridge Neighborhood 2.5 development will
consist of detached single-family residences. Thus, the Detached Residential
Development category has been highlighted to cleariy illustrate which general
pollutant categories are anticipated from the project area.
General Pollutant Categories
Priority
Project
Categories Sediments Nutrients Heavy Metals Organic Compounds Trash & Debris Oxygen Demanding Substances Oil & Grease Bacteria & Viruses Pesticides -va«|^Jti.-
M m
Attached
Residentiai
Development
X x X p(i/ pv-/ p X
Commercial
Deveiopment
>100,000 ft^
p(i) p(i) p(2) x p(5) X p(3) p(5)
Automotive
Repair
Shops
x x X
Restaurants x X X X
Hillside
Development
>5,000 ft^
X x X X X X
Parking Lots p(1) p(1) x X pd) X pd)
Streets,
Highways &
Freeways
X pd) x X(4) X p(5) X
Retail Gas
Outiets x X(4) X X
X = anticipated
P = potential
(1) A potential pollutant if landscaping exists on-site.
(2) A potential pollutant if the project includes uncovered parking areas.
(3) A potential pollutant if land use involves food or animal waste products.
(4) Including petroleum hydrocarbons.
(5) Including solvents.
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La Costa Ridge - Neighborhood 2.5
Storm Water Management Pian
3.2 - Sediment
Soils or other surface 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, smother bottom dwelling organisms, and suppress aquatic
vegetative growth.
3.3 - Nutrients
Inorganic substances, such as nitrogen and phosphorous, that commonly exist in the
form of mineral salts that are either dissolved or suspended in water. Primary
sources of nutrients in urban mnoff 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.
3.4 - Trash & Debris
Examples include paper, plastic, leaves, grass cuttings, and food waste, which 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. In areas where stagnant water is
present, 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.
3.5 - Oxygen-Demanding Substances
Biodegradable organic material as well as chemicals that react with dissolved
oxygen in water to form other 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.
3.6 - Oil & Grease
Characterized as high high-molecular weight organic compounds. Primary sources
of oil and grease are petroleum hydrocarbon products, motor products from leaking
vehicles, oils, waxes, and high-molecular weight fatty acids. Elevated oil and grease
content can decrease the aesthetic value ofthe water body, as well as the water
quality.
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La Costa Ridge - Neighborhood 2.5
Storm Water Management Plan
3.7 - Bacteria and Viruses
Bacteria and viruses are ubiquitous micro-organisms that thrive under certain
environmental conditions. Their proliferation is typically caused by the transport of
animals or human fecal wastes from the watershed. Water, containing excessive
bacteria and viruses can alter the aquatic habitat and create a hannful environment
for humans and aquatic life. Also, the decomposition of excess organic waste
causes increased grovAh of undesirable organisms in the water.
3.8 - Pesticides
Pesticides (including herbicides) are chemical compounds commonly used to control
nuisance growth or prevalence of organisms. Excessive application of a pesticide
may result in runoff containing toxic levels of its active componenL
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La Costa Ridge - Neighborhood 2.5
Storm Water Management Plan
CHAPTER 4 - CONDITIONS OF CONCERN
4.1 - Receiving Watershed Descriptions
As shown in the watershed map on the following page, the pre-developed and post-
developed La Costa Ridge site drains to the San Marcos Creek watershed.
The Regional Water Quality Control Board has identified San Marcos Creek as part
ofthe Carisbad Hydrologic Unit, San Marcos Hydrologic Area, and the Batiquitos
Hydrologic Subarea (basin number 904.51).
4.2 - Pollutants of Concern in Receiving Watersheds
San Marcos Creek is not listed on the EPA's 303(d) List of endangered watenways
(included in this Chapter). Per the "Water Quality Plan for the San Diego Basin", the
beneficial uses for San Marcos Creek include agricultural supply, contact water
recreation, non-contact recreation, warm freshwater habitat, and wildlife habitat. In
addition, San Marcos Creek is exempted as being designated as a Municipal water
supply.
Table 3-3 from the "Water Quality Plan for the San Diego Basin" (included at the end
of this Chapter) lists water quality objectives for a variety of potential pollutants
required to sustain the beneficial uses of the San Marcos hydrologic area.
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ARLSBAD
ENONITAS WATERSHED MAP FOR
LA COSTA RIDGE
cnv OF CARLSBAD. CALIFORNIA
26 Los Monos HSA
(904.31) Agua Hedionda
Lagoon
Bacterial
Indicators^ 6.8 acres 1998
Sedimentation /
Siltation
27 Los Monos HSA
(904.31) Agua Hedionda
Creek lower portion Total Dissolved
ouiiua lower 7 miles 2002
28 San Marcos HA
(904.50)
Pacific Ocean
Shoreline at Moonlight State Beach Bacterial
Indicators^ 0.4 miles 1998
29 Escondido Creek
HA (904.60)
Pacific Ocean
Shoreline at San Elijo Lagoon Bacterial
Indicators^ 0.44 miles 1998
30 San Elijo HSA
(904.61)
San Elijo
Lagoon
Bacterial
Indicators^ 150 acres 1998 30 San Elijo HSA
(904.61)
San Elijo
Lagoon
Eutrophic 330 acres
Sedimentation /
Siltation 150 acres
31 San Dieguito HU
(905.00)
Pacific Ocean
Shoreline at San Dieguito Lagoon Mouth Bacterial
Indicators^ 0.86 miles 1998
32 Del Dios HSA
(905.21 and
905.22)
Green Valley
Creek Sulfate 1 mile 2002
33 Del Dios HSA Hodges Entire Reservoir Coior Entire 2002
(905.21) Reservoir Entire Reservoir Nitrogen
Phosphorus
Totai Dissolved
Solids
Reservoir
(1104 acres)
34 Felicita HSA
(905.23) Felicita Creek Total Dissolved
Solids
lower 0.92
miles 2002
35 Felicita HSA
(905.23) Kit Carson
Creek should in 905.21 HSA Totai Dissolved
Solids 1 mile 2002
36 Highland HSA
(905.32) Cloverdale
Creek
• Phosphorus
Total Dissolved
Solids
1.2 miles 2002
37 Sutheriand HSA
(905.53)
Sutherland
Reservoir Entire Reservoir Color Entire
Reservoir 2002
38 Miramar Reservoir
HA (906.10)
Los
Penasquitos
Lagoon
Entire Lagoon Sedimentation /
Siltation 469 acres 1998
39 Miramar Reservoir
HA (906.10)
Pacific Ocean
Shoreline
Ton-ey Pines State Beach at Del
Mar (Anderson Canyon)
Bacterial
Indicators^ 0.4 miles 2002
40 Scripps HA
(906.30) Pacific Ocean
La Jolla Shores Beach at El Paseo
Grande Bacterial 3.9 miles 1998 40 Scripps HA
(906.30)
Shoreline La Jolia Shores Beach at Caminito
Dei Oro
indicators^
La Jolla Shores Beach at
Vaiiecitos
La Jolia Shores Beach at Ave de ia
Playa
I
I
I
I
last updated 9/23/2003
S:\WQS\303dlist\SD Staff Report-2002\F1NAL VERSIONSMisted Waterbodies-2002jclsMable 4 (Sep03 page 3 of 6
Table 2-2. BENEFICIAL USES OF INLAND SURFACE WATERS
BENEFICIAL USE
1,2
Inland Surface Waters Hydrologic Unit
Basin Number
M
U
N
A
G
R
1
N
D
P
R
0
C
G
W
R
F
R
S
H
P
0
W
R
E
C
1
R
E
C
2
B
1
0
L
W
A
R
M
C
0
L
D
W
1
L
D
R
A
R
E
S
P
W
N
San Dlego Cbiirity Coastai Streams - cbntihued
Buena Vlsta Lagoon 4.21 See Coastal Waters- Table 2-3
Buena Vista Greek 4.22 + • • • • • .•
Buena Vlsta Creek 4.21 • • • • •
Agua Hedionda 4.31 See Coastal Waters-Table 2-3
Agua Hedionda Creek 4.32 • • • • • • •
Buena Creek 4.32 • • • • • • •
Agua Hedionda Creek 4.31 • • • • • • •
Letterbox canyon 4.31 • • • e • • •
Canyon de las Encinas 4.40 + 0 • • •
Sin Marcos Creek Watershed
Batiquitos Lagoon 4.51 See Coastal Waters-Table 2-3
San Marcos Creek 4.52 -t-• • • •
unnamed intermittent streams 4.53 + • • • • •
San Marcos Creek Watershed
San Marcos Creek 4.51 + • • • • •
Encinitas Creek 4.51 + • • • • •
• Existing Beneficial Use
0 Potential Beneficial Use
-1- Excepted From MUN (See Text)
1 Waterbodies are listed multiple times if they cross hydrologic area or sub area boundaries.
Beneficial use designations apply to all tributaries to the Indicated waterbody, if not listed separately.
Tabla 2-2
BENEFICIAL USES
Mareh 12, 19S7
2-27
Table 2-3. BENEFICIAL USES OF COASTAL WATERS
Coastal Waters
Pacific Ocean
Dana Point Harbor
Del Mar Boat Basin
Mission Bay
Oceanside Harbor
San Diego Bay
Coastal Lagoons
' Tijuana River Estuary
Mouth of San Dlego River
Los Penasquitos Lagoon
San Dieguito Lagoon
Batiquitos Lagoon
San Elijo Lagoon
Aqua Hedionda Lagoon
Hydrologic
Unit Basin
Number
BENEFICIAL USE
I
N
D
N
A
V
R
E
C
1
R
E
C
2
C
.0
M
M
B
I
0
L
E
S
T
W
I
L
D
•
9
R
A
R
E
M
A
R
A
Q
U
A
11.11
7.11
6.10
5.11
4.51
5.61
4.31
1 Includes the tidal prisms of the Otay and Sweetwater Rivers.
2 Fishing from shore or boat permitted, but other water contact recreational (REC-1) uses are prohibited.
@ Existing Beneficial Use
Table 2-3
BENEFICIAL USES 2-47
M
I
G
R
W
U
o
f»
o
it
W
A
R
M
S
H
E
L
L
#
March 12, 1997
Table 3-2. WATER QUALITY OBJECTIVES
Concentrations not to be exceeded more than 10% of the time during any one one year period.
Const tiuent (mg/L or as rioted)
Inland Surface Waters Hydrologic
Unit Basin
Number
TDS Cl SO, %Na N&P Fe Mn MBAS B ODOR Turb
NTU
Color
Units F
SAN LUIS REY HYDROLOGIC UNIT 903.00
Lower San Luis HA 3.10 500 250 250 60 a 0.3 0.05 0.5 0.75 none 20 20 1.0
Monserat HA 3.20 500 250 250 60 a 0.3 0.05 0.5 0.75 none 20 20 1.0
Warner Valley HA 3,30 500 250 250 60 a 0.3 0.05 0.5 0.75 none 20 20 1.0
CARLSBAD HYDROLOGIC UNIT 904.00
Loma Alta HA 4.10 -----
•-
---none 20 20 1.0
' Buena Vista Creek HA 4.20 500 250 250 60 a 0.3 0.05 0.5 0.75 none 20 20 1.0
Agua Hedionda HA 4.30 500 250 250 60 a 0.3 0.05 0.5 0.75 none 20 20 1.0
Encinas HA 4.40 ---------none 20 20 1.0
San Marcos HA 4.50 500 250 250 60 a 0.3 0.05 0.6 0.75 none 20 20 1.0
Escondido Creek HA 4.60 500 250 250 60 a 0.3 0.05 0.5 0.75 none 20 20 1.0
SAN DIEGUITO HYDROLOGIC UNIT 906.00
Solana Beach HA 5.10 500 250 250 80 a 0.3 0.05 0.5 0.75 none 20 20 1.0
Hodges HA 5.20 500 250 250 60 a 0.3 0.05 0.5 0.75 none 20 20 1.0
San Pasqual HA 5.30 500 250 250 60 a 0.3 0.05 0.5 0.75 none 20 20 1.0
Santa Maria Valley HA 5.40 500 250 250 60 a 0.3 0.06 0.5 0.76 none 20 20 1.0
Santa Ysabel HA 5.50 500 250 250 60 a 0.3 0.05 0.5 0.75 none 20 20 1.0
PENASQUITOS HYDROLOGIC UNIT 906.00
Miramar Reservoir HA 6.10 500 250 250 60 a 0.3 0.05 0.6 0.75 none 20 20 1.0
Poway HA 6.20 500 250 250 60 a 0.3 0.05 0.5 0.75 none 20 20 1.0
HA - Hydrologic Area
HSA - Hydrologic Sub Area (Lower casa letters indicate endnotes following the table.)
Table 3-2
WATER QUALITY OBJECTIVES Page 3-23 Saptamber 8, 1994
La Costa Ridge - Neighborhood 2.5
Storm Water Management Pian
CHAPTER 5 - FLOW-BASED BMPS
5.1 - Design Criteria
Flow-based BMPs shall be designed to mitigate the maximum flowrate of runoff
produced from a rainfall intensity of 0.2 inch per hour. Such BMPs utilize either
mechanical devices (such as vaults that produce vortex effects) or non-mechanical
devices (based on weir hydraulics and specially designed filters) to promote settling
and removal of pollutants from the runoff.
Per the request of the City of Carisbad, 85**^ percentile flow calculations were
performed using the Rational Method. The basic Rational Method mnoff procedure
is as follows:
Design flow (Q) = C * I * A
Runoff Coefficient I - In accordance with the County of San Diego standards, the
weighted runoff coefficient for all the areas draining to the treatment unit was
determined using the areas analyzed in the final engineering hydrology report. The
runoff coefficient is based on the following characteristics of the watershed:
Land Use - Single Family Residential in Developed Areas
Soil Type - Hydrologic soil group D was assumed for all areas. Group
D soils have very slow infiltration rates when thoroughly wetted.
Consisting chiefly of clay soils with a high swelling potential, soils with a
high permanent water table, soils with clay pan or clay layer at or near
the surface, and shallow soils over neariy impervious materials. Group
D soils have a very slow rate of water transmission.
Rainfall Intensity (1) - Regional Water Quality Control Board regulations and NPDES
criteria have established that flow-based BMPs shall be designed to mitigate a
rainfall intensity of 0.2 inch per hour
Watershed Area (A) - Corresponds to total area draining to treatment unit.
5.2 - Vortechs Treatment Units
The Vortechs Storm Water Treatment System is designed to efficientiy remove grit,
contaminated sediments, metals, hydrocarbons and floating contaminants from
surface runoff. Combining swiri-concentrator and flow-control technologies to
eliminate turbulence within the system, the Vortechs System ensures the effective
capture of sediment and oils and prevents resuspension of trapped pollutants for
flows up to 25 cfs.
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La Costa Ridge - Neighborhood 2.5
Storm Water Management Pian
Other features ofthe Vortechs Systems include the following:
Large capacity system provides an 80 percent net annual Total
Suspended Solids (TSS) removal rate.
Unit is installed below grade.
Low pump-out volume and one-point access reduce maintenance costs.
Design prevents oils and other floatables from escaping the system
during cleanout.
Enhanced removal efficiencies of nutrients and heavy metals with offline
configuration.
The tangential inlet to the system creates a swiriing motion that directs settleable
solids into a pile towards the center ofthe grit chamber. Sediment is caught in the
swiriing flow path and settles back onto the pile after the storm event is over.
Floatable entrapment is achieved by sizing the low flow control to create a rise in the
water level of the vault that is sufficient to just submerge the inlet pipe with the 85^^
percentile flow.
5.3 - Pollutant Removal Efficiency Table
Pollutant of Concern BMP Categories
Hydrodynamic
Separation
Devices'^'
Sediment M-H
Nutrients L-M
Heavy Metals L-M
Organic Compounds L-M
Trash & Debris M-H
Oxygen Demanding Substances
Bacteria
Oil & Grease L-H
Pesticides
(1) The County will periodically assess the performance characteristics of these BMPs to
update this table.
(2) Proprietary Structural BMPs. Not all serve the same function.
L (Low): Low removal efficiency (roughly 0-25%)
M (Medium): Medium removal efficiency (roughly 25-75%)
H (High): High removal efficiency (roughly 75-100%)
U: Unknown removal efficiency, applicant must provide evidence supporting use
Sources: Guidance Specifying Management Measures for Sources of Nonpoint Pollution in
Coastal Waters (1993), National Stonvwater Best Management Practices Database (2001),
and Guide for BMP Selection in Urban Developed Areas (2001).
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La Costa Ridge - Neighborhood 2.5
Storm Water Management Plan
5.4 - Maintenance Reguirements
Flow-based storm water treatment devices should be inspected periodically to
assure their condition to treat anticipated runoff. Maintenance of the proposed
Vortechnics units includes inspection and maintenance 1 to 4 times per year.
Maintenance of the Vortechs units involves the use of a "vactor truck", which clears
the grit chamber of the treatment unit by vacuuming all the grit, oil and grease, and
water from the sump. Typically a 3-man crew is required to periderm the
maintenance of the treatment unit. Properiy maintained Vortechs Systems will only
require evacuation ofthe grit chamber portion ofthe system. In some cases, it may
be necessary to pump out all chambers. In the event of cleaning other chambers, it
is imperative that the grit chamber be drained first.
Proper inspection includes a visual observation to ascertain whether the unit is
functioning properiy and measuring the amount of deposition in the unit. Floatables
should be removed and sumps cleaned when the sump storage exceeds 85 percent
of capacity specifically, or when the sediment depth has accumulated within 6 inches
of the dry-weather water level. The rate at which the system collects pollutants will
depend more heavily on site activities than the size of the unit.
Maintenance ofthe site BMPs will be the responsibility ofthe Homeowners
Association. A maintenance plan will be developed and will include the following
information:
Specification of routine and non-routine maintenance activities to be
performed
A schedule for maintenance activities
Name, qualifications, and contact information for the parties responsible for
maintaining the BMPs
For proper maintenance to be performed, the storm water treatment facility must be
accessible to both maintenance personnel and their equipment and materials.
5.5 - Operations and Maintenance Plan
The operational and maintenance needs of a Vortechs unit include:
Inspection of structural integrity and screen for damage.
Animal and vector control.
Periodic sediment removal to optimize performance.
Scheduled trash, debris and sediment removal to prevent obstruction.
The facility will be inspected regulariy and inspection visits will be completely
documented:
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La Costa Ridge - Neighborhood 2.5
Storm Water Management Plan
Preventive maintenance activities for a flow-based treatment unit are:
Trash and Debris Removal - trash and debris accumulation will be monitored
during both the dry and wet season and after every large storm event (rainfall
events in excess of 1 inch). Trash and debris will be removed from the
Vortechs unit annually (at the end ofthe wet season). Trash and debris will
also be removed when material accumulates to 85% of the unit's sump
capacity, or when the floating debris is 12 inches deep (whichever occurs
first).
Sediment Removal - sediment accumulation will be monitored during both the
wet and dry season, and after every large storm (1.0 inch). Sediment will be
removed from the Vortechs unit annually (at the end of the wet season).
Sediment will also be removed when material accumulates to 85% of the
unit's sump capacity, or when the floating debris is 12 inches deep (whichever
occurs first). Disposal of sediment will comply with applicable local, county,
state or federal requirements.
Corrective maintenance is required on an emergency or non-routine basis to
correct problems and to restore the intended operation and safe function of a
Vortechs unit. Corrective maintenance activities include:
Removal of Debris and Sediment
Structural Repairs - Once deemed necessary, repairs to structural
components of a Vortechs unit will be completed within 30 working days.
Qualified individuals (i.e., the manufacturer representatives) will conduct
repairs where structural damage has occurred.
5.6 - Schedule of Maintenance Activities
Target Maintenance Frequency - At a minimum, treatment unit should be cleaned
annually.
Maintenance Activity - Annual inspection and cleanout
Clear grit chamber unit with vactor truck.
Perform visual inspection
Remove floatables
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W.O. 2352-93 6/30/2005 12:40 PM
La Costa Ridge - Neighborhood 2.5
Storm Water Management Plan
5.7 - Annual Operations & Maintenance Costs
The following costs are intended only to provide a magnitude of the costs involved in
maintaining BMPs. Funding shall be provided by the Master Home Owners
Association for the La Costa Ridge.
Approximate annual maintenance costs for the proposed Vortechs unit are outiined
below. Costs assume a 3 man crew:
Maintenance for Vortechs model 9000:
Periodic Inspection, Maintenance and Monitoring = $800
Annual Cleanout Cost = $2,250
Subtotal = $3,050
Contingency = $305
Total = $3,355
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La Costa Ridge - Neighborhood 2.5
Storm Water Management Plan
CHAPTER 6 - SOURCE CONTROL BMPS
6.1 - Landscaping
Manufactured slopes shall be landscaped with suitable ground cover or installed with
an erosion control system. Homeowners will be educated as to the proper routine
maintenance to landscaped areas including trimming, pruning, weeding, mowing,
replacement or substitution of vegetation in ornamental and required landscapes.
Per the RWQCB Order, the following landscaping activities are deemed unlawful
and are thus prohibited:
Discharges of sediment
Discharges of pet waste
Discharges of vegetative clippings
Discharges of other landscaping or construction-related wastes.
6.2 - Urban Housekeeping
Fertilizer applied by homeowners, in addition to organic matter such as leaves and
lawn clippings, all result in nutrients in storm water runoff. Consumer use of
excessive herbicide or pesticide contributes toxic chemicals to runoff. Homeowners
will be educated as to the proper application of fertilizers and herbicides to lawns
and gardens.
The average household contains a wide variety of toxins such as oil/grease,
antifreeze, paint, household cleaners and solvents. Homeowners will be educated
as to the proper use, storage, and disposal of these potential storm water runoff
contaminants.
Per the RWQCB Order, the following housekeeping activities are deemed unlawful
and are thus prohibited:
Discharges of wash water from the cleaning or hosing of impervious
surfaces including parking lots, streets, sidewalks, driveways, patios,
plazas, and outdoor eating and drinking areas (landscape irrigation and
lawn watering, as well as non-commercial washing of vehicles in
residential zones, is exempt from this restriction.).
Discharges of pool or fountain water containing chloride, biocides, or
other chemicals.
Discharges or runoff from material storage areas containing chemicals,
fuels, grease, oil, or other hazardous materials.
Discharges of food-related wastes (grease, food processing, trash bin
wash water, etc.).
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La Costa Ridge - Neighborhood 2.5
Storm Water Management Plan
6.3 - Automobile Use
Urban pollutants resulting from automobile use include oil, grease, antifreeze,
hydraulic fluids, copper from brakes, and various fuels. Homeowners will be
educated as to the proper use, storage, and disposal of these potential stonn water
contaminants.
Per the RWQCB Order, the following automobile use activities are deemed unlawful
and are thus prohibited:
Discharges of wash water from the hosing or cleaning of gas stations,
auto repair garages, or other types of automotive service facilities.
Discharges resulting from the cleaning, repair, or maintenance of any
type of equipment, machinery, or facility including motor vehicles,
cement-related equipment, port-a-potty servicing, etc.
Discharges of wash water from mobile operations such as mobile
automobile washing, steam cleaning, power washing, and carpet
cleaning.
The Homeowners Association will make all homeowners aware of the
aforementioned RWQCB regulations through a homeowners' education program.
6.4 - Site Design BMPs
Priority projects, such as the La Costa Ridge Neighborhood 2.5 project, shall be
designed to minimize, to the maximum extent practicable the introduction of
pollutants and conditions of concern that may result in significant impact, generated
from site runoff to the storm water conveyance system. Site design components can
significantiy reduce the impact of a project on the environment. The following design
techniques have been proposed to accomplish this goal.
- Implementing on-lot hydrologically functional landscape design and
management practices; Additional detail regarding landscaping design is
discussed in section 7.2.
- Minimizing project's impervious footprinL Methods of accomplishing this goal
include constructing streets, sidewalks, and parking lots to the minimum
widths necessary without compromising public safety. Another method for
minimizing impervious area includes incorporating landscaped areas in the
drainage system to encourage infiltration and reduce the amount of directly
connected impervious areas.
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La Costa Ridge - Neighborhood 2.5
Storm Water Management Pian
CHAPTER 7 - TREATMENT CONTROL BMP DESIGN
VORTECHS TREATMENT UNIT
7.1 - BMP Location
Treatment control BMP design includes a single flow based treatment unit (shown
on BMP Location Map located on the following page). The unit is located at the end
ofthe La Costa Ridge 2.5 storm drain within Corinthia Street, priorto discharging to
the existing storm drain system.
7.2 - Determination of Design Treatment Flow
The 85"^ percentile design flow rates have been calculated using the Rational
Method. Required data for the Rational Method treatment flow determination include
the following:
- Runoff Coefficient (C)
- Rainfall Intensity (I) = 0.20 inches per hour
- Drainage area to treatment unit (A)
A runoff coefflcient was derived based upon a weighted average of each area
tributary to the treatment unit and the associated runoff coefficient.
The following table summarizes the parameters used for determination of design
flows the proposed flow-based treatment unit.
DESIGN RUNOFF DETERMINATION SUMMARY TABLE
Treatment Unit
Runoff
Coefficient
(C)
85'"
Percentile
Rainfall
(inches/hour)
Drainage
Area
(acres)
85*'' Pet.
Design Flow
(cfs)
Corinthia Street 0.42* 0.2 69.4 5.8
*= weighted C coefficient
7.3 - Vortechs Treatment Unit Selection
The proposed Vortechs unit is an offline precast treatment unit. The 85*^ percentile
design flow rate will be forced into the treatment area by a diversion weir built in the
upstream junction. Flows in excess of the design flow rate pass over the weir and
proceed downstream. The calculations determining the peak flows being forced into
the treatment during a 100-year storm event will govern the sizing requirements
necessary to adequately treat the entire flow passing through the unit during this
significant rainfall event.
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LEGEND
WATERSHED BOUNDARY -
WATER QUALITY UNIT o
rUMMC VRHUM^MSMM
BMP LOCATION EXHIBIT FOR
LA COSTA RIDGE
NEIGHBORHOOD 2.5
CITY OF CARLSBAD, CALIFORNIA
SHEET
1
OF
1
La Costa Ridge - Neighborhood 2.5
Storm Water Management Pian
The following table shows the treatment capacity of the proposed Vortechs, or
approved equivalent unit.
VORTECHS UNIT TREATMENT CAPACITY TABLE
Treatment Unit
85*" Pet.
Design Flow
(cfs)
Recommended
Vortechs
Model
Treatment Capacity
(cfs)
Corinthia Street 5.8 9000 14.0
As it is evident above, the treatment capacity of the Vortechs Model 9000 is greater
than the treatment flow provided from the 85'^^ percentile flow (see attached Vortech
unit sizing data). As such, a Vortechs Model 9000 has been selected to treat storm
water runoff from the proposed La Costa Ridge Neighborhood 2.5 development.
DE:DE h:\5w quality\2352\93 ridge 2.5\swmp-04.doc
W.O. 2352-93 7/1/2005 1:26 PM
mi
85TH PERCENTILE PEAK FLOW AND VOLUME DETERMINATION
Modified Rational Method - Effective for Watersheds < 1.0 mi^
Hunsaker & Associates - San Diego
Note; Only Enter Values in Boxes - Spreadsheet Will Calculate Rennaining Values
Project Name La Costa Ridge Neighborhood 2.5 |
Work Order 2352-93 1
Jurisdiction City of Carlsbad j
BMP Location [BIVIP #1 - Corinthia Street
85th Percentile Rainfall = 0.68 inches
(from County Isopluvial Map)
Developed Drainage Area = 24.5 acres
Natural Drainage Area = 44.9 acres
Total Drainage Area to BMP ' 69.4 acres
Dev. Area Percent Impervious = | 40 |%
Overall Percent Impervious = 14 %
Dev. Area Runoff Coefficient •
Nat. Area Runoff Coefficient =
0.55
0.35
Runoff Coefficient = 0.42
Time of Concentration = | 13.0 | minutes
(from Drainage Study)
RATIONAL METHOD RESULTS
Q = CIA where
V = CPA where
Q-
C =
V:
C^
P =
A:
85th Percentile Peak Flow (cfs)
Runoff Coefficient
Rainfall Intensity (0.2 inch/hour per RWQCB mandate)
Drainage Area (acres)
85th Percentile Runoff Volume (acre-feet)
Runoff Coefficient
85th Percentile Rainfall (inches)
Drainage Area (acres
Using the Total Drainage Area:
C = 0.42
I = 0.2 inch/hour
P = 0.68 inches
A = 69.4 acres
Q =
V =
5.84 cfs
1.65 acre-feet
Using Developed Area Only:
C =
I =
P =
A =
Q-
V =
0.55
0.2 inch/hour
0.68 inches
24.5 acres
2.70 cfs
0.76 acre-feet
Vortechs ™ Stormwater Treatment Systems
Vortechnics
w
FLOW CALCULATIONS
La Costa Ridge 2.1-2.5
Carlsbad, CA
Model 9000
System BMP #2 @ Sta 81+91.16
Vortechs Orifice
Cd^ 0.56
1.70
Crest Elevation (ft) = 352.01
A(ft')^
Vortechs Weir
Cd = 3.33
Weir Crest Length (ft) = 0
Crest Elevation (ft) = 355.93
Bypass Weir
Cd = 3.3
Weir Crest Length (ft) = 7
Crest Elevation (ft) = 353.2
Head Elevation Orifice Flow Weir Flow Bypass Flow Total Fiow
(ft) (ft) (cfs) (cfs) (cfs) (cfs)
0.00 352.01 0.00 0.00 0.00 0.00
0.25 352.26 0.88 0.00 0.00 0.88
0.50 352.51 2.48 0.00 0.00 2.48
0.75 352.76 4.55 0.00 0.00 4.55
1.00 353.01 6.04 0.00 0.00 6.04
1.25 353.26 7.15 0.00 0.37 7.51
1.50 353.51 8.10 0.00 4.05 12.15
1.75 353.76 8.96 0.00 9.76 18.72
2.00 354.01 9.74 0.00 16.93 26.67
2.25 354.26 10.46 0.00 25.32 35.78
2.50 354.51 11.14 0.00 34.75 45.89
2.75 354.76 11.77 0.00 45.14 56.91
3.00 355.01 12.38 0.00 56.39 68.77
3.25 355.26 ' • 12.95 0.00 68.45 81.40
3.50 355.51 13.51 0.00 81.26 94.77
4.48 356.50 15.49 0.00 138.28 153.77
Calculated by:
357.0
356.5
356.0
355.5
355.0
c o 354.5
> 354.0
LU 353.5
353.0
352.5
352.0
351.5
Vortechs"^" System
Stage Discharge Curve
)ass Crest )ass Crest
On
0.0 20.0 40.0 60.0 80.0 100.0
Discharge (cfs)
120.0 140.0 160.0 180.0
66S0ADSBf>yiP #2 @ Sta 81+91.16.xls 3/23/2005
Treatment System
The Vortechs Stormwater Treatment System, a major advancement
in oil and grit separator technology, efficiently removes grit, contami-
nated sediments, metals, hydrocarbons and floating contaminants
irom sun'ace runoff.
The Vortechs System's innovative design combines
swirl-concentrator and flow-control technologies to
optimize treatment efficiency. These features
ensure effective capture of sediment and oils, and
prevent resuspension of trapped, pollutants - even
at flow rates of up to 25 cfs.
• Large system capacity provides an 80% net
annual TSS removal rate
• Installs below grade, minimizing land use
• Custom-built of precast concrete near the job site
• Low pump-out volume and one-point access
reduce maintenance costs
• Unique design prevents oils and other float-
ables from escaping the system during cleanout
"We have worked with
Vortechnics on at least a
dozen stormwater
managennent plans for
some of our largest
corporate clients. Their
efficient turnaround on
our requests for technical
support and CADD
drawings has expedited
the permitting process
for our clients. We turn
to Vortechnics when
we need innovative
stormwater solutions."
- Lawrence Marsiglio, RE.
Senior Civii Engineer,
Baralcos-Landino, Inc.
m m
Vortechs Systems may be
used in a wide range of
water-quality improvement
applications, including:
Wetlands/Waterfront
Protection
Retail
Development
Industrial Sites
Municipal Improvements
Commercial Development
Transportation Facilities
Existing Site Retrofits
Flow Controi
^ the ^^!3Ptec^^D
Stormwater Treatment System
Perforated Covers^
I
I
I
I
I
I
I
I
I
-I f
Seal
INV. i
6' to 9'
Typical
t
3'to 4'
I
Plan View
To begin the design of your
Vortechs System, refer to the
sizing chart below and com-
plete a Specifier's Worksheet to
provide details about your site
and design flows. Then simply
fax or mail the worksheet to >
Vortechnics with your site plan,
and we'll produce detailed
Vortechs System scale draw-
ings free of charge.
Elevation View
r-'.-.Peakf'-'^--'"
Desigrr- ^ Sediment . B?rc7!ipptiM:S-.;';?j^
^j.Diameter'/'AFeai-S ^, --ftrZft'-e. ~ Ffowi^ - ,
1-...11;^ Qfs. t-"-'
S&'sl-iXiW;'^,:^':-^
ft
.„,--,'1000 _ 3/7 I.B : . 75 '.9x3 -^-m
'r '2000 4/13 2.8 1 25 '10x4-' P
5/20 4.5 1 75 11x5 I'j^
i|:||B/2a _:--,.• B.O • V^^2^S'® 12x6 ^fJm
^|-t.E:5:7/38 8.5 13x7- g
;p,7D0Q UU ,., 11 .• ^ •..4.p^^^;:#
3/B4 : • 14.0 '^'v 4;75::i;;f( 15 X'
10/79 17 5 5 5 • 16x10 ^
IBOOO 12/113 25 0 7 0 18x 12 ^
Engineering Notes
- A) For in-lSe Vdi-techs Sy'^B^ wittiout a ibypass, sizing criteria is ba^ed oh providing one square foot of grit:,'
chamber surf ace area for each IOO gpm of peak desigri storm flaw rate [e.g., 'lO-year storm).- - For more; i. •
details about Vbrteohnics sizing'criteria refer to Vortechnics Technical Bulletin 3. v..;.
• B) Sediment storage volume assunies'a 3 ,foot sump. • .' ;:^^.- .Vf •': ;< ;,/-''J^-.': ' ;.V'<jr.'^ '"'•'' ;'•• •' .' •
. C) Construction details niay vary dependirig oh the specific; application. Any alterations to the sizing chart specifi-
cations virill appear on Vortechnics dimensional and shbp drawings. Please call Vortechnics for the weight of spe-
cific Vbrtechs systems if needed.,.. ;'.,/•','!. ;,:: ;,:' ,•.,'>'; • V..-..
Special Note: Oil storage capacity, when it is heeded tomeet a specific requirement for spill containment, can ba
sized to'meet the storage requirement with the selected nnodel.- Vorteohnics technical staff will optimize system
, geornetry tt meet containment requirements writhin a correctiy sized Vortechs Sys^^ • , ~
:• Metric Spedfication licari: svailable by calling VdrK^ '•''.:•-,
Vortechs System Inlet/Outlet Configurations
Vortechs Systems can be configured to accommo-
date various inlet and outlet pipe orientations.
The inlet pipe can enter the end or side of the
tank at right angles - outlet pipes can exit the end
or the side of system at most angles.
End Inlet
0 0 jJ Offline U
1 Side Inlet
0
To
\ I Pretreat.Tient pj^g,;
7 T
,5*l'**frv^3*2S|51^ '-"TT'*-——'5,1 0-
ElevatiariiView
The weir and orifice fiow controls - >
'?'l?S|§S|ayjKifiie:|^
n View: Dry-Weather flow rate subsides - ' v " -
1) Initial Wet Weather Phase
During a two-month storm event the water level begins to
rise above the top of the inlet pipe. This influent control
feature reduces turbulence and avoids resuspension .
of pollutants.
2) Transition Phase
As the inflow rate increases above the controlled outflow
rate, the tank fills and the floating contaminant layer accu-
mulated from past storms rises. Swirling action increases
at this stage, while sediment pile remains stable.
3) Full Capacity Phase
When the high-flow outlet approaches full discharge, storm
drains are flowing at peak capacity. The Vortechs System is •
designed to match your design storm flow and provide treat-
ment throughout the range of storm events without bypass-
ing. To accommodate very high flow rates, Vortechnics can
4) Storm Subsidence Phase/Cleaning
Treated runoff is decanted at a controlled rate, restoring the
water level to a low dry-weather volume and revealing a conical
pile of sediment. The low water level facilitates inspection and
cleaning, and significantly reduces maintenance costs. The
system's central baffle prevents transfer of floatables to the
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SECTION 02721
STORMWATER TREATMENT SYSTEM
PART 1.00 GENERAL
1.01 DESCRIPTION
A. Work included:
• -The Contractor, and/or a manufacturer selected by the Contractor and approved
by the Engineer, shall furnish all labor, materials, equipment and incidentals
required and install all precast concrete stormwater treatment systems and
appurtenances in accordance with the Drawings and these specifications.
B. Related work described elsewhere:
1. Unit Masonry
2. Miscellaneous Metals
3. Waterproofing
1.02 QUALITY CONTROL INSPECTION
A. The quality of materials, the process of manufacture, and the finished sections
shall be subject to inspection by the Engineer. Such inspection may be made at
ihe place of manufacture, or on the work site after delivery, or at both places, and
the sections shall be subject to rejection at any time if raateriarconditions fall to
meet any of the specification requirements, even though sample sections may
have been accepted as satisfactory at the place of manufacture. Sections
rejected after delivery to the site shall be marked for identification and shall be
removed from the site at once. All sections which have been damaged beyond
repair during delivery wiil be rejected and, if already installed, shall be repaired to
the Engineer's acceptance level, if permitted, or removed and replaced, entirely
at the Contractor's expense.
B. Ail sections shall be inspected for general appearance, dimensions, soundness,
ete. The surface shall be dense, close textured and free of blisters, cracks,
roughness and exposure of reinforcemenL
C. Imperfections may be repaired, subject to the acceptance of the Engineer, after
demonstration by the manufacturer that strong and permanent repairs result.
Repairs shall be carefully inspected before final acceptance. Cement mortar
used for repairs shall have a minimum compressive strength of 4,000 psi at the
end of 7 days and 5,000 psi at the end of 28 days when tested in 3 inch diameter
by 6 inch long cylinders stored in the standard manner. Epoxy mortar may be
utilized for repairs.
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1.03 SUBMITTALS
A. Shop Drawings
The Contractor shall be provided with dimensional drawings and, when specified,
utilize these drawings as the basis for preparation of shop drawings showing
details for construction, reinforcing, joints and any cast-in-place appurtenances.
Shop drawings shaii be annotated to indicate all materials to be used and all
applicable standards for materials, required tests of materials and design
assumptions for structural analysis. Design calculations and shop drawings shall
be certified by a Professional Engineer retained by the system manufacturer or
contractor and licensed in the state where the system is to be instaiied. Shop
drawings shall be prepared at a scale of not less than 1/4" per foot. Six (6) hard
copies of said shop drawings shall be submitted to the Engineer for review and
approval.
B. Affidavit on patent infringement
The Contractor shall submit to the Engineer, prior to installation of the stormwater
treatment system, an affidavit regarding patent infringement rights stating that
any suit or claim against the Owner due to alleged Infringement rights shall be
defended by the Contractor who will bear all the costs, expenses and attomey's
fees incurred thereof.
PART 2.00 PRODUCTS
2.01 MATERIALS AND DESIGN
A. Concrete for precast stormwater treatment systems shall conform to ASTM
C 857 and C 858 and meet the following additional requirements:
1. The wall thickness shall not be less than 6 inches or as shown on the
dimensional drawings. In all cases the wai! thickness shall be no less than
the minimum thickness necessary to sustain HS20-44 loading requirements
as determined by a Licensed Professional Engineer.
2. Sections shall have tongue and groove or ship-lap joints with a butyl mastic
sealant conforming to ASTM C 990.
3. Cement shall be Type III Portland cement conforming to ASTM C 150.
4. Pipe openings shall be sized to accept pipes of the specified size(s) and
material(s), and shall be sealed by the Contractor with a hydraulic cement
conforming to ASTM C 595M
5. Internal metal components shall be aluminum alloy 5052-H32 In accordance
with ASTM B 209.
6. Brick or masonry used to build the manhole frame to grade shall conform to
ASTM C 32 or ASTM C 139 and the Masonry Section of these Specifications.
\\MDI\SYS\DATA\VORTECHN\Ef/AIL\STDETAIL\VORTSPEC.DOC SECTION 02721 Page 2
7. Casting for manhole frames and covers shall be in accordance with The
Miscellaneous Metals Section ofthese Specifications.
8. All sections shall be cured by an approved method. Sections shall not be
shipped until the concrete has attained a compressive strength of 4,000 psi or
util 5 days after fabrication and/or repair, whichever is the longer.
9. A buiimen sealant in conformance with ASTM C 990 shaii be utilized in
affixing the aluminum swirl chamber to the concrete vault
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2.02 PERFORMANCE
Each stormwater treatment system shall adhere to the following performance specifications
at the specified design flows, as listed below:
able 2.02
Vortechs
Model
Swirl
Chamber
Diameter
(ft)
Design
Treatment
Capacity
(cfs)
Sediment
Storage
(yd')
1000 3.67 2.3 1.00
2000 4 2.8 1.25
3000 5 4.5 1.75
4000 6 6.0 2.50
5000 7 8.5 3.25
7000 8 11.0 4.00
9000 9 14.0 , 4.75
11000 10 17.5 5.50
16000 12 25.0 7.00
Each stormwater treatment system shall include a circular aluminum "swiri chamber" (or "grit
chamber") with a tangential inlet to induce a swiriing flow pattern that will accumulate and
store settleable solids in a manner and a location that will prevent re-suspension of previously
captured particulates. Each swiri chamber diameter shall not be less than the diameter listed
in Table 2.02 (neglecting chamber wall thickness).
Each stormwater treatment system shall be of a hydraulic design that includes flow controls
designed and certified by a professional engineer using accepted principles of fluid mechanics
that raise the water surface inside the tank to a pre-detennined level In order to prevent the
re-entrainment of trapped floating contaminants.
Each stormwater treatment system shall be capable of removing 80% of the net annual Total
Suspended Solids (TSS). Individual stormwater treatment systems shall have the Design
Treatment Capacity listed in Table 2.02, and shall not resuspend trapped sediments or re-
entrain floating contaminants at flow rates up to and including the specified Design Treatment
Capacity.
Individual stomnwater treatment systems shall have usable sediment storage capacity of not
less than the corresponding volume listed in Table 2.02. The systems shall be designed such
\\MDI\SYS\DATA\V0RTECHN\EMA1L\STDETA1L\V0RTSPEC.DOC SECTION 02721 Paqe 3
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that the pump-out volume is less than of the total system volume. The systems shall be
designed to not allow surcharge of the upstream piping network during dry weather conditions.
A water-lock feature shall be incorporated into the design of the stormwater treatment system
to prevent the introduction of trapped oil and floatable contaminants to the downstream piping
during routine maintenance and to ensure that no oil escapes the system during the ensuing
rain event Direct access shall be provided to the sediment and floatable contaminant storage
chambers to facilitate maintenance. There shali be no appurtenances or restrictions within
these chambers.
The stormwater treatment system manufacturer shall furnish documentation which supports
all product performance claims and features, storage capacities and maintenance
requirements.
Stormwater treatment systems shall be completely housed within one rectangular structure.
2.03 MANUFACTURER
Each stormwater treatment system shall be of a type that has been installed and used
successfully for a minimum of 5 years. The manufacturer of said system shall have
been regulariy engaged in the engineering design and production of systems for the
physical treatment of stormwater runoff.
TM
Each stormwater treatment system shall be a Vortechs System as manufactured by
Vortechnics, Inc., 41 Evergreen Drive, Portland, Maine 04103, phone: 207-878-3662,
fax: 207-878-8507; and as protected under U.S. Patent # 5,759,415.
PART 3.00 EXECUTION
3.01 INSTALLATION
A. Each Stormwater Treatment System shall be constructed according to the sizes
shown on the Drawings and as specified herein. Install at elevations and
locations shown on the Drawings or as otherwise directed by the Engineer.
B. Place the precast base unit on a granular subbase of minimum thickness of six
inches after compaction or of greater thickness and compaction if specified
elsewhere. The granular subbase shall be checked for level prior to setting and
the precast base section of the trap shall be checked for level at all four corners
after it is set. .Ifthe slope from any corner to any other corner exceeds 0.5% the
base section shall be removed and the granular subbase material re-leveled.
C. Prior to setting subsequent sections place butimen sealant in conformance with ASTM
C990-91 along the construction joint in the section that is already in place.
D. After setting the base and wall or riser sections install the circular swiri chamber
wall by bolting the swiri chamber to the side walls at the three (3) tangent points
and at the 3-jnch wide inlet tab using HILTI brand concrete anchors or equivalent
1/2-inch diameter by 2-3/4" minimum length at heights of approximately three
inches (3") off the floor and at the mid-height of the completed trap (at locations
of pre-drilled holes in aluminum" components). Seal the bottom edge of the swiri
\\MDi\SYS\DATA\V0RTECHN\EMAlL\STDETAlL\V0RTSPEC.DOC SECTION 02721 Page 4
chamber to the trap floor with the supplied aluminum angle flange. Adhere VA
thick by 1" wide neoprene sponge material to the flange with half of it's width on
the horizontal leg of the flange and half of it's width on the vertical leg. The
aluminum angle flange shall be affixed to the floor with a minimum 3/8" diameter
by 2-3/4" drop in wedge anchor at the location of the predrilled holes. Affix the
swiri chamber to the fiange with hex head %" x 1-1/2" zinc coated self- tapping
screws at the location of the predrilled holes. Seal the vault sidewalls to the
outside of the swiri chamber from the floor io the same height as the iniet pipe
invert using butyi mastic or approved equal.
E. Prior to setting the precast roof section, butimen sealant equal to ASTM C990 shall be
placed" along the top of the baffle wall, using more than one layer of mastic if
necessary, to a thickness at least one inch (1") greater than the nominal gap between
the top of the baffie and the roof section.
The nominal gap shall be detemnined either by field measurement or the shop
drawings. After placement ofthe roof section has compressed the butyl mastic sealant
in the gap, finish sealing the gap with an approved non-shrink grout on both sides of
the gap using the butyl mastic as a backing material to which to apply the grout Also
apply non-shrink grout to the joints at the side edges of the baffle wall.
F. After setting the precast roof section of the stormwater treatment system, set
precast concrete manhole riser sections, to the height required to bring the cast
iron manhole covers to grade, so that the sections are vertical and in true
alignment with a 1/4 inch maximum tolerance allowed. Backfill in a careful
manner, bringing the fill up in 6" lifts on all sides. If leaks appear, clean the inside
joints and caulk with lead wool to the satisfaction of the Engineer. Precast
sections shall be set in a manner that will result in a watertight joint. In all
instances, installation of Stormwater Treatment Systems shall conform to ASTM
specification C891 "Standard Practice For Installation of Underground Precast
Utility Structures".
G. Plug holes in the concrete sections made for handling or other purposes with a
nonshrink grout or by using grout in combination with concrete plugs.
H. Where holes must be cut in the precast sections to accommodate pipes, do all
cutting before setting the sections in place to prevent any subsequent jarring
which may loosen the mortar joints. The Contractor shall make all pipe
connections.
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La Costa Ridge - Neighborhood 2.5
Storm Water Management Plan
Chapter 8 - FISCAL RESOURCES
8.1 - Fiscal Mechanism Selection
The table below illustrates the maintenance mechanism selection criteria and its
associated fiscal funding source. The shaded portion ofthe table highlights the
mechanism associated with the La Costa Ridge Neighborhood 2.5 project.
Increased risk, complexity, cost or other maintenance factors»»»»»»»»>
(Private Responsibility) (Public Responsibility)
First Category Second Category Third Category Fourth Category
Importance of
IVlaintenance
Minimal
concern;
inherent in
BMP or
property
stewardship
Need to make sure
private owners
maintain, and
provide County
ability to step in &
perform
maintenance
Warrants Flood
Controi Dist. (FCD)
assuming
responsibility, with
funding related to
project
Broader public
responsibility for
maintenance and
funding (beyond
project)
Typical BMPs Biofilter (Grass
swaie, grass
strip, vegetated
buffer);
Infiltration
basin/trench
[First cat. plus:]
Minor wetland swale;
Small detention
basin; Single storm
drain insert / Oil-
water separator /
Catch basin insert &
screen
[Second cat. plus:]
Wetland swaie or
bioretention;
Detention basin
(extended/dry); Wet
ponds & wetlands;
Multiple storm drain
inserts; Filtration
Systems
[Third cat. plus:]
Retrofit pubiic
storm drain
inserts, etc.
Master plan
faciiity
that serves area
larger than project
Mechanisms 1. Stormwater Ordinance requirement
[section 67.819(a)&(b)], with code
enforcement
2. Nuisance abatement with costs
charged back to property owner
3. Condition in ongoing permit such as
a Major Use Permit (if project has
MUP)
4. Notice to new purchasers
[67.819(e)]
5. Subdivision public report "white
papers" to include notice of
maintenance responsibility
1. Dedication to FCD.
2. Formation of
benefit area
3. FCD maintenance
documentation
1. Dedication to
FCD or
County.
FCD / County
maintenance
documentation
Recorded
easement
agreement
w/covenant
binding on
successors
Funding
Source(s)
None
necessary
Security (Cash
deposit. Letter of
Credit, or other
acceptable to County)
for interim period.
Agreement for
security to contain
provisions for release
or refund, if not used.
Start-up interim:
Developer fee
covering 24 months
of costs
Permanent:
FCD Assessment
per FCD Act Sec
105-17.5
Varies: gas tax for
BMP in road
ROW, Transnet
for CIP projects.
Special funding or
General funding
for others.
DE:MF h:\sw quality\2352\93 ridge 2.5\swnip-04.doc
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La Costa Ridge - Neighborhood 2.5
Storm Water Management Plan
8.2 - Agreements (Mechanisms to Assure Maintenance)
There is a single flow based treatment unit on the La Costa Ridge Neighborhood 2.5
project site for storm water quality treatment. Storm water quality units fall within
maintenance category two based on the County's Guidelines for the Stormwater
Maintenance Plan. The Home Owners Association will be responsible to perform
the maintenance activities and to ensure adequate funding. The maintenance
agreement(s) will be found with the Home Owners Association's secretary. Security
to fund "backup" maintenance which would be performed by the City in the event
that the HOA's maintenance is inadequate is required.
The County of San Diego Watershed Protection, Stormwater Management, and
Discharge Control Ordinance require ongoing maintenance of BMPs to ensure the
proper function and operation of theses BMPs. Costs for this maintenance will be
the responsibility of the Home Owners Association at the time of inception and by
the contractor during construction ofthe development. The flow based treatment
units will require maintenance activities as outlined in Section 5 ofthis report.
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