HomeMy WebLinkAboutCT 07-08; LA COSTA SPA & RESORT VILLAS; STORM WATER MANAGEMENT PLAN; 2008-07-08I
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JUL 082008
CITY OF CARLSBAD
PLANNING DEPT.
RECEIVED
Storm Water Management Plan
LA COSTA RESORT - TENTATIVE MAP
PLANNING AREA 1 - BUILDING 9A - 9B, 10A -10E
CITY OF CARLSBAD
SAN DIEGO COUNTY, CALIFORNIA
(MAP NO. 14984, CT 07-08
SUP 03-03, 03-06)
March 27, 2008
Revised July 8, 2008
Prepared for:
W2007 La Costa I, LLC
2100 Costa Del Mar Road
Carlsbad, CA 92009
CONTACT: Chevis Hosea, President
Prepared by:
RBF CONSULTING
5050 Avenida Encinas, Suite 260
Carlsbad, CA 92008
go CO3 103 760.476.9193
CONSULTING
Contact Person:
Tim Thiele, P.E. ((1jI C60283
V.
CNIL
ØW&
RBFJN55-100221
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La Costa Resort -Tentative Map
Planning Area 1, Building 9A-9B, 10A-10E
Storm Water Management Plan
STORM WATER MANAGEMENT PLAN
TABLE OF CONTENTS
TABLEOF CONTENTS..................................................................................................I
I PURPOSE OF SCOPE...............................................................................2
2 PROJECT INFORMATION.........................................................................2
2.1 Project Description......................................................................................2
2.2 Project Activities .........................................................................................2
3 WATER QUALITY CONDITIONS OF CONCERN......................................4
3.1.1 Potential Pollutants.....................................................................................4
3.1.2 Pollutants of Concern..................................................................................6
3.1.3 Conditions of Concern ................................................................................7
4 POST-CONSTRUCTION BEST MANAGEMENT PRACTICE PLAN..........8
4.1 Site Design BMPs.......................................................................................8
4.2 Source Control BMPs .................................................................................9
4.3 BMPs for Individual Project Categories.......................................................8
4.4 Treatment Control BMPs...........................................................................11
4.5 Construction-Phase BMPs........................................................................15
5 LOW IMPACT DEVELOPMENT...............................................................16
5.1 Porous Pavement .....................................................................................16
5.2 Roof Runoff Disconnect............................................................................16
5.3 Parking Lot Filter Strips.............................................................................16
6 MAINTENANCE .......................................................................................16
POST-CONSTRUCTION BMP SITE MAP....................................................................18
TABLE OF FIGURES
Figure2-1 Vicinity Map ................................................................................................3
Figure 4-1 Kristar Floguard Plus® Inlet Insert ............................................................15
LIST OF TABLES
Table 3-1 Anticipated and potential pollutants by project type (San Diego County,
2002a) ........................................................................................................4
Table 3-2 Summary of 303(d) impairments of downsteam water bodies.....................7
Table 4-1 Site design BMPs alternatives.....................................................................8
Table 4-2 Source-control BMP alternatives.................................................................9
Table 4-3 Carlsbad SUSMP Individual Project Categories........................................12
Table 4-4 Treatment Control BMP Selection Matrix (San Diego County, 2002a).......13
Table 4-5 Treatment-Control BMP alternatives.........................................................13
APPENDIX
A STORM WATER REQUIREMENTS APPICABILITY CHECKLIST
B BMP CALCULATIONS
C DRAINAGE NARRATIVE
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I STORM WATER MANAGEMENT PLAN
I D APPROVED STORM WATER MANAGEMENT PLAN
I I PURPOSE AND SCOPE
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This report is a site-specific storm water management plan that supplements the
approved Master Storm Water Management Plan prepared by Rick Engineering, dated
October 29, 2003. Presented within this document are the water quality measures
required for the development of Planning Area #1 - Building 9A, 9B, 10A-IOE at the La
I Costa Resort and Spa, in order to fulfill the requirements of the City of Carlsbad. This
report also describes the implementation and maintenance of water quality Best-
Management Practices that will be installed on the site.
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2 PROJECT INFORMATION
I 2.1 Project Description
1 The project is located within the City of Carlsbad at the La Costa Resort and Spa (CT-
07-08). The campus is bound by El Camino Real to the west, Arenal Road to the north,
I of
and San Marcos Creek to the south. Planning Area 1 is located at the southeast corner
Arenal Road and Estrella De Mar Road (see Figure 2-1).
Existing site conditions include two paved parking lots (0.55 acre and 1.29 acre). There
is an existing building and associated landscaping area within the project site. The site
I is located approximately 2,000 feet from the San Marcos Creek. The project site
contains side slopes of 2:1 or less. The project is not located within the Coastal Zone. Its
land use designation is Travel/Recreation Commercial. There are no sanitary landfills,
I historical, archaeological or paleontological resources located within a half-mile of the
project site.
1 2.2 Project Activities
The project consists of seven, two and three story, commercial dwelling unit buildings
I both attached and detached (37,090 sq. ft., including balconies and common area), an
adjacent parking lot (54,400 sq. ft.), and a proposed valet lot (16,100 sq. ft.).
Landscaping will be incorporated into the planter medians and at the perimeter of
I building and each lot. There is one private driveway proposed as part of this project. The
driveway will provide access to the site from Estrella De Mar Road. Drainage from the
project will be directed into a proposed storm drain system and connected to an existing
I piping system that will ultimately outlet to the San Marcos Creek located at the southerly
boundary of the La Costa Resort campus. Approximately 90% of the site will be re-
graded as part of this project.
I The project is considered a high priority project by the City of Carlsbad (See Appendix
A - "Storm Water Requirements Applicability Checklist"). Therefore, the project will
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incorporate all applicable permanent storm water management requirements. These
include the site design and source control BMPs, BMPs applicable to individual priority
project categories, and treatment control BMP requirements.
I La Costa Resort - Tentative Map
Planning Area 1, Building 9A-9B, bA-10E 2
Storm Water Management Plan . . -
STORM WATER MANAGEMENT PLAN
Figure 2-1 ,vicinity Map (Reference Thomas Bros. 1127,1147)
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Tt-
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SITE
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La Costa Resort - Tentative Map
Ranning Area 1, Building 9A-9B, bA-10E 3
Storm Water Management Plan
STORM WATER MANAGEMENT PLAN
3 WATER QUALITY CONDITIONS OF CONCERN
3.1 Potential Pollutants
The proposed project is not expected to generate significant amounts of pollutants, but
many constituents are generally anticipated for projects in this category (Table 3-1).
Table 3.1 Anticipated and potential pollutants by project type (San Diego County, 2002a).
1' Anticipated Pollutants General Pollutant Categories
P Potential Pollutants
U C
U, -a
Priority Project Categories U,
(I)
a) (1) 5) U
C U
- U a 5) E
0
> -o C
-
W .? C
- (I )
E
-D C 0 - a a)
E >
o 0 > x U
- a (I) Z I o a M CL
Detached Residential
Attached Residential I 1' 1 p(1) p(2) p 1
Commercial (>100,000 sf) p) P(l)
-
p) ./ p(s) 1 p(s) p(5)
Auto Repair Shops
Restaurants
Hillside Development (>5,000 sf)
Parking Lots p11 1 1 p(l) I p(i)
Streets, Highways, and Freeways I P111 1 p(4) I p(l) v'
Retail Gasoline Outlets I p(4) 1 1
A potential pollutant if landscaping exists on-site;
A potential pollutant if the project includes uncovered parking areas;
A potential pollutant if land use involved food or animal waste products;
Including petroleum hydrocarbons;
Including solvents.
As indicated in Section 2.2, the project consists of two commercial dwelling building
totaling 22,740 square feet, five detached commercial dwelling unit buildings totaling
14,350 square feet and 70,500 sq. ft. of associated parking lot area (See Site Map), thus
the project falls into the parking lot priority project category, as indicated in Table 3-1.
Potential pollutants of concern associated with this priority project category include:
+ Sediments (since there will be landscaped areas on site);
La Costa Resort - Tentative Map
Planning Area 1, Building 9A-9B, bA-10E 4
Storm Water Management Plan PF
STORM WATER MANAGEMENT PLAN
Nutrients (since there will be landscaped areas on site);
Metals (associated with vehicle parking);
:• Litter and trash collecting in the drainage systems;
Oxygen-demanding substances including biodegradable organic material and
chemicals;
+ Oils, grease, and other hydrocarbons emanating from paved areas on the site;
Pesticides used to control nuisance growth; and
Sediments are 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, lower young aquatic organisms survival rates, smother
bottom dwelling organisms, and suppress aquatic vegetation growth.
3.1.2 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.
1 3.1.3 Metals
Metals are raw material components in non-metal products such as fuels, adhesives,
I paints, and other coatings. The primary sources 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
I 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
I shellfish. Environmental concerns, regarding the potential for release of metals to the
environment, have already led to restricted metal usage in certain applications.
I 3.1.4 Trash and Debris
Trash (such as paper, plastic, polystyrene packing foam, and aluminum materials) and
I biodegradable organic matter (such as leaves, grass cuttings, and food waste) are
general waste products on the landscape. The presence of trash and debris may have a
significant impact on the recreational value of a water body and aquatic habitat. Excess
I 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
I hydrogen sulfide.
La Costa Resort - Tentative Map
Planning Area 1, Building 9A-9B, bA-bE 5
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STORM WATER MANAGEMENT PLAN
3.1.5 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.
1 3.1.6 Oil and Grease
Oil and grease are characterized as high-molecular weight organic compounds. The
I 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
I 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.
1 3.1.7 Pesticides
Pesticides (including herbicides) are chemical compounds commonly used to control ' nuisance growth of organisms. Excessive application of a pesticide may result in runoff
containing toxic levels of its active component.
3.2 Pollutants of Concern
The Environmental Protection Agency (EPA) is the primary federal agency responsible
I for management of water quality in the United States. The Clean Water Act (CWA) is
the federal law that governs water quality control activities initiated by the EPA and
others. Section 303 of the CWA requires the adoption of water quality standards for all
I surface water in the United States. Under Section 303(d), individual states are required
to develop lists of water bodies that do not meet water quality objectives after required
levels of treatment by point source dischargers. Total maximum daily loads (TMDLs) for
all pollutants for which these water bodies are listed must be developed in order to bring
1 them into compliance with water quality objectives.
The project is located within the San Marcos hydrologic area of the Carlsbad hydrologic
I unit. Receiving waters for the project site include the San Marcos Creek, the Batiquitos
Lagoon and ultimately the Pacific Ocean.
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Table 3-2 summarizes the receiving waters and their classification by the RWQCB Region 9.
Hydrologic Approximate 303(d)
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Receiving Water Unit Code Distance
From Site Impairment(s)
Pacific Ocean Shoreline— San Marcos HA 904.50 2.5 mi Bacteria Indicators
Batiguitos Lagoon - San Marcos HA 904.51 0.5 mi None
I San Marcos Creek - San Marcos HA 904.51 2,000 ft DDE, Phosphorus,
Sediment Toxicity
La Costa Resort - Tentative Map
Planning Area 1, Building 9A-9B, 10A-10E 6
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STORM WATER MANAGEMENT PLAN
The primary pollutants of concern are sediment toxicity and phosphorus. Secondary
pollutants of concern are metals trash and debris, oxygen demanding substances, oil
and grease and pesticides.
3.3 Conditions of Concern
According to the City of Carlsbad SUSMP, a change to a priority project site's hydrologic
regime would be considered a condition of concern if the change would impact
downstream channels and habitat integrity. However, the changes in hydrologic
characteristics resulting from the development of this site have already been
incorporated into the downstream storm drain system design. Additionally, the
hydrologic regime described here will not be negatively impacted with the proposed
project. Previously, Planning Area 1 existed as a paved roadway with several large
homes, and was largely impervious. The revised site plan proposes a similar land use
with comparable runoff values.
Runoff from Planning Area 1 will discharge into an existing 18-inch storm drain located
within Estrella De Mar Road. The existing storm water drains via the campus system to
a diversion structure located just downstream of a CDS unit. The diversion structure
initially directs water to the 36-inch, recently slip-lined CMP, beneath El Camino Real
and as flows increase, water is split with some flow being diverted to San Marcos Creek.
Storm water that drains via the existing 36-inch drain line beneath El Camino Real
discharges directly into an open area at the east end of Batiquitos Lagoon. There is no
defined channel at this location for sediment to be created and transported. Storm water
that drains via the 30-inch storm drain (which ultimately is planned to upsized to a 42-
inch RCP) discharges into San Marcos Creek, just upstream of El Camino Real.
Downstream of this location the Creek is stable, showing no erosion. A separate
drainage report (Drainage Study for La Costa Resort & Spa, prepared by Hunsaker &
Associates, dated September 15, 2006) has been prepared to support the design of the
existing storm drain system. This study assumed ultimate conditions for the La Costa
Resort & Spa campus when determining pipe sizes and impacts to downstream facilities.
The existing storm drain system will not be adversely impacted by the revised building
layout. The integrity of downstream channels and existing habitats will also be
maintained. Since runoff from the project discharges into new and existing drainage
facilities that are verified to accommodate peak runoff flow rates from a 100-year storm
event, there are no conditions of concern associated with the project.
The Federal Insurance Rate Map (FIRM) for this area shows that the project's location is
out of the 100-year floodplain.
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La Costa Resort - Tentative Map
Planning Area 1, Building 9A-9B, 1OA-10E 7
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4 POST-CONSTRUCTION BEST MANAGEMENT
I PRACTICE PLAN
I The project site incorporates four major types of post-construction best management
practices (BMPs). These types are (1) site design BMPs; (2) source control BMPs; (3)
site design and source control BMPs for individual priority project categories; and (4)
I treatment control BMPs. In general, site design BMPs and source control BMPs reduce
the amount of storm water and potential pollutants emanating from a site and focus on
pollution prevention. Treatment-control BMPs target anticipated potential storm water
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pollutants. The project will apply these BMPs to the maximum extent practicable.
4.1 Site Design BMPs
Site design BMPs aim to conserve natural areas and minimize impervious cover,
especially impervious areas 'directly connected' to receiving waters, in order to maintain
I or reduce increases in peak flow velocities from the project site. The U.S. EPA (2002)
has listed several site design BMPs that can be implemented in development projects.
The project has incorporated site design BMPs to the maximum extent practicable.
Table 4-1 lists site-design BMP alternatives and indicates the practices that have been I applied to the project site.
Table 4-1 Site design BMPs alternatives.
I 0 Buffer Zones 0 Open Space Design
LI Narrower Residential Streets LI "Green" Parking
LI Alternative Turnarounds Z Alternative Payers
l 0 Urban Forestry LI Conservation Easements
0 Eliminating Curbs And Gutters LI Landscape Design
I Z Other (Explained Below)
4.1.1 Protect Slopes and Channels
I Site runoff will be directed away from the tops of slopes, and all slopes will be vegetated
to provide permanent stabilization.
4.2 Source Control BMPs
Source-control BMPs are activities, practices, and procedures (primarily non-structural) l that are designed to prevent urban runoff pollution. These measures either reduce the
amount of runoff from the site or prevent contact between potential pollutants and storm
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water. In addition, source-control BMPs are often the best method to address non-storm
(dry-weather) flows. Table 4-2 lists source-control BMP alternatives and indicates the
practices that will be applied at the project site.
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La Costa Resort - Tentative Map
Planning Area 1, Building 9A-9B, bA-10E 8
I Storm Water Management Plan
STORM WATER MANAGEMENT PLAN
Table 4-2 Source-control BMP alternatives.
Z Storm Drain Stenciling and Signage LI Homeowner Outreach
Z Material and Trash Storage Area Design LI Lawn and Gardening Practices
• Efficient Irrigation Systems LI Water Conservation
Z Low-Irrigation Landscape Design LI Hazardous Waste Management
LI On-Lot Treatment Measures LI Trash Management
LI Riprap or Other Flow Energy Dissipation Z Outreach for Commercial Activities
LI Other (Explained Below)
4.2.1 Efficient Landscape Design and Irrigation Practices
Efficient landscape design and irrigation practices can be an effective source-control to
prevent pollution in storm water and dry-weather flows. The completed project will
implement principles of common-area efficient irrigation, runoff-minimizing landscape
design, and an effective landscape maintenance plan to the maximum extent
practicable.
4.2.1.1 Common-Area Efficient Irrigation
Automatic irrigation systems should include water sensors, programmable irrigation
timers, automatic valves to shut-off water in case of rapid pressure drop (indicating
possible water leaks), or other measures to ensure the efficient application of water to
the landscape and prevent unnecessary runoff from irrigation. Drip irrigation and other
low-water irrigation methods should be considered where feasible. Common elements
of efficient irrigation programs include:
:. Reset irrigation controllers according to seasonal needs.
:• Do not over-water landscape plants or lawns.
Keep irrigation equipment in good working condition.
:. Promptly repair all water leaks.
I 4.2.1.2 Runoff-Minimizing Landscape Design
Landscape designs that group plants with similar water requirements can reduce excess
I irrigation runoff and promote surface infiltration. Landscape designs should utilize non-
invasive native plant species and plants with low water requirements when possible.
The Resort takes abundant advantage of planting pots for various classes and sizes of I plants. Potted plants are efficient for water conservation.
4.2.1.3 Landscape Maintenance
I The landscape maintenance plan should include a regular sweeping program of
impervious surfaces, litter pick-up, and proper equipment maintenance (preferably off-
site), and proper use of chemicals to help eliminate sources of storm water pollutants.
Common elements of an effective landscape maintenance plan include:
: A regularly rotating schedule of maintenance ensures the property is in a perpetual
I state of good cleanliness. Maintenance obligations include regular sweeping of
La Costa Resort - Tentative Map
Planning Area 1, Building 9A-9B, bA-10E 9
I Storm Water Management Plan WF
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sidewalks, driveways, and gutters, and staff members' job duties include perpetual
litter pick-up. Also, if necessary, the resort provides convenient trash receptacles for
public use located throughout the property.
:• Avoid using water to clean sidewalks, driveways, and other areas.
:• All landscape maintenance equipment is cleaned in an isolated area within the
maintenance yard located offsite at the south end of the campus. Minimize water
use and do not use soaps or chemicals. A commercial wash-rack facility is to be
used whenever possible.
:. Keep all landscape equipment in good working order. Fix all leaks promptly, and use
drip pans/drip cloths when draining and replacing fluids. Perform all repairs and
equipment maintenance in the maintenance yard located on the south side of the
campus. Protect all nearby storm water inlets. Keep regular logs of major
equipment repairs. All spent fluids are to be collected and disposed of properly.
:. Materials with the potential to pollute runoff (soil, pesticides, herbicides, fertilizers,
detergents, petroleum products, and other materials) are handled, delivered, applied,
and disposed of with care following manufacturer's labeled directions and in
accordance with all applicable Federal, state, and local regulations. Volatile
chemicals are stored and locked in an isolated storage sheds with paved flooring.
Pesticides and fertilizers, if used, will be applied according to manufacturer's
I directions and will not be applied prior to a forecast rain event. Any material
broadcast onto paved surfaces (e.g. parking areas or sidewalks) will be promptly
swept up and properly disposed.
1 4.2.2 Material and Trash Storage Area Design
I There is no outdoor material storage area associated with the proposed project. For
Buildings 9A and 9B the trash storage area is located on the first floor. Chutes are
located on upper levels. Trash is regularly collected from the storage area for disposal.
For Buildings 1OA-10E, housekeeping regularly removes trash from rooms and disposes
I it directly into Resort containers.
4.2.3 Pollution Prevention Outreach for Owners and Guests
I One source-control best management practice for commercial sites is pollution
prevention outreach. For instance, at the lease signing or as part of the lease, the tenant
I can be presented with a brochure to encourage them to develop and implement a
pollution prevention program. The pollution prevention program would emphasize
source reduction, reuse and recycling, and energy recovery. Hotel guests are also
I encouraged to support pollution prevention; recycling containers are located regularly
throughout the Resort. Also, the Resort kindly offers guests the opportunity to reuse
towels, where appropriate, to help relieve the burden on municipal water use. The
following offer suggestions for measures to be included in these areas of pollution
I prevention. The pollution prevention outreach should choose the measures most
applicable to the project site for the project site.
I 4.2.3.1 Source Reduction
La Costa Resort - Tentative Map
Planning Area 1, Building 9A-9B, bA-10E 10
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:• Incorporating environmental considerations into the designing of products, buildings,
and manufacturing systems enables them to be more resource efficient.
:. Rethinking daily operations and maintenance activities can help industries eliminate
wasteful management practices that increase costs and cause pollution.
Controlling the amount of water used in cleaning or manufacturing can produce less
wastewater.
:• Re-engineering and redesigning a facility or certain operation can take advantage of
newer, cleaner and more efficient process equipment.
Buying the correct amount of raw material will decrease the amount of excess
materials that are discarded (for example, paints that have a specified shelf life).
4.2.3.2 Reuse/Recycling
I .:. Using alternative materials for cleaning, coating, lubrication, and other production
processes can provide equivalent results while preventing costly hazardous waste
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generation, air emissions, and worker health risks.
Using "green" products decreases the use of harmful or toxic chemicals (and are
more energy efficient than other products).
I • One company's waste may be another company's raw materials. Finding markets for
waste can reduce solid waste, lessen consumption of virgin resources, increase
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income for sellers, and provide an economical resource supply for the buyers.
4.2.3.3 Energy Recovery
I Using energy, water, and other production inputs more efficiently keeps air and water
clean, reduces emissions of greenhouse gases, cuts operating costs, and improves
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productivity.
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4.2.3 Storm Drain Stenciling and Signage
All new storm drain grate inlets constructed as part of this project will be signed with the
message "No Dumping - Drains to Oceans" or equivalent message as directed by the
I City.
1 4.3 BMPs for Individual Project Categories
The City of Carlsbad SUSMP lists ten individual project categories for which BMPs must
I be provided. Table 4-3 below lists these individual project categories and indicates that
the individual category of parking areas is applicable to the proposed project. Inlets
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equipped with filter inserts treat any runoff generated and additional treatment is
La costa Resort - Tentative Map
Planning Area 1, Building 9A-9B, bA-10E 11
I Storm Water Management Plan
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provided as discussed in Section 4.4. Slopes will be vegetated to provide permanent
stabilization and to prevent erosion.
Table 4-3 Carlsbad SUSMP Individual Project Categories
El Private Roads
LI Residential Driveways & Guest Parking
LI Dock Areas
LI Maintenance Bays
LI Vehicle Wash Areas
LI Outdoor Processing Areas
LI Equipment Wash Areas
Z Parking Areas
LI Fueling Area
0 Hillside Landscaping
4.4 Treatment Control BMPs
I Post-construction "treatment control" storm water management BMPs provide treatment
for storm water emanating from the project site. Structural BMPs are an integral element
of post-construction storm water management and may include storage, filtration, and
I infiltration practices. BMPs have varying degrees of effectiveness versus different
pollutants of concern. Table 4-4 below summarizes which treatment control BMPs and
removal effectiveness for certain constituents.
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La Costa Resort - Tentative Map
Planning Area 1, Building 9A-9B, bA-10E 12
I Storm Water Management Plan
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Table 4-4 Treatment Control BMP Selection Matrix (San Diego County, 2002a).
Treatment Control BMP Categories
O High Removal Efficiency
15 Medium Removal Efficiency
Low Removal Efficiency
? Unknown Removal Efficiency
-o C
C
0 = C C
.2
0
- o a-
o 2
. U,
Pollutant of Concern CL 0 0
E
.2
(I)
Sediment e 0 0 0 • 0 e
Nutrients • e e e • e •
Heavy Metals 15 e 0 • 0
Organic Compounds ? ? • ______
Trash & Debris 0 ? e 0
Oxygen Demanding Substances e • e
Bacteria 0 ? • e •
Oils and Grease ? ? • 0
Pesticides ? ?
Including trenches and porous pavement.
Such as CDS units.
Original Sources: Guidance Specifying Management Measures for Sources of
Nonpoint Pollution in Coastal Waters (1993), National Stormwater Best Management
Practices Database (2001), and Guide for BMP Selection in Urban Developed Areas
(2001).
4.4.1 Treatment Control BMP Selection
The selection, design and siting of structural BMPs for Planning Area 1 depend largely
on the project-wide drainage plan and previously approved Master Storm Water
Management Plan, prepared by Rick Engineering, dated October 29, 2003. BMP
alternatives were evaluated for their relative effectiveness for treating potential pollutants
from the project site; technical feasibility; relative costs and benefits; and applicable
legal, institutional, and other constraints. Table 4-5 below lists treatment-control BMP
alternatives and identifies the BMPs selected for the project site.
Treatment Control BMPs function to mitigate pollutants of concern anticipated from
project activities. Receiving waters downstream of the project site are impaired for
bacterial indicators, DDE, Phosphorus and sediment toxicity, as shown in Table 3-2. The
proposed project activities are not anticipated to produce bacteria, DDE, phosphorus or
sediment toxicity, as shown in Table 3-1, there are no primary pollutants of concern
associated with the project, these are considered secondary pollutants of concern.
Treatment control BMPs for this project were chosen to treat the secondary pollutants of
concern at no less than a "low removal efficiency" as shown in Table 4-4.
La Costa Resort - Tentative Map
Planning Area 1, Building 9A-9B, 1OA-1OE 13
Storm Water Management Plan BF'
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STORM WATER MANAGEMENT PLAN
Table 4-5 Treatment-Control BMP alternatives.
Vegetated Swales and/or Strips LI Wet Ponds/Wetlands
O Dry Extended Detention Basins 0 Infiltration Basins
0 Bio-Retention Areas 0 Sand or Organic Filters
Hydrodynamic Separators LI Infiltration Trenches
Z Catch Basin/Inlet Inserts Z Other (Explained Below)
Of the treatment control options available for this project, infiltration practices are not
feasible due to the preponderance of hydrologic soil type D throughout the site, which
has poor infiltration properties. Wet ponds and constructed wetlands rely on a perennial
water source, which is generally difficult to sustain in the project's arid environment.
While filtration devices, such as sand filters and media filters, typically have medium to
high removal efficiencies for the project's pollutants of concern, they are aesthetically
unsuitable for use in developments such as this project. An underground sand/media
filter might improve aesthetics, but these are not recommended for drainage areas
greater than 2 acres (2003 California New Development BMP Handbook, Fact Sheet
TC-40), and the proposed project covers 4.58 acres. Since the proposed project site
consists of a generally flat graded pad, implementing several filters for smaller drainage
areas is not feasible due to the lack of required head needed to ensure that water
passes through the filter.
4.4.1.1 Drainage Filter Inserts
To provide additional treatment and removal of potential pollutants, drainage inlet inserts
will be installed in all storm drain inlets capturing runoff from the parking lots. Kristar
Floguard Plus® inserts or equivalent will be specified to treat runoff for hydrocarbons and
trash/debris. The Kristar Floguard Plus® inlet insert is shown in Figure 4-1, and is
similar in design and function to other proprietary inlet inserts. Surface runoff enters the
inlet and passes over/through and adsorbent material to remove hydrocarbons, while
sediments and trash/debris are collected in the hanging basket. Recommended
maintenance consists of three inspections per year (once before the wet season and two
during, or more as may be needed) plus replacement of the adsorbent when it is more
than 50% coated with pollutants and removal of excessive sediment/debris. Each inlet
insert costs about $570 and is available locally through Downstream Services (760-746-
2544 or 760-746-2667). The inserts can be installed by Downstream Services for
additional cost or by the project construction contractor. Maintenance costs are
estimated at about $400 per year. (Refer to Appendix B for design calculations).
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I La Costa Resort - Tentative Map
Planning Area 1, Building 9A-9B, bA-10E 14
I Storm Water Management Plan
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STORM WATER MANAGEMENT PLAN
Figure 4-1 Kristar Floguard Plus® Inlet Insert
--
Trap
,It skt
Ph' Porchs
lJ1
a—,
-- - SIDE VIEW
4.4.1.2 Hydrodynamic Separators
An in-line storm water treatment unit (CDS unit) exists at the downstream end of the
campus-wide storm drain system, as proposed within the approved Master Storm Water
Management Plan, prepared by Rick Engineering, dated October 29, 2003. The storm
water treatment units are mechanical separators that physically reduce sediment, trash,
debris, and oil and grease from the flow and pesticides that attached to sediment. The
unit is considered a hydrodynamic separator system. The hydrodynamic separator
systems rank low to medium in removal efficiency for the project's pollutants of concern.
Refer to the approved Master Drainage Study for La Costa Resort & Spa, prepared by
Hunsaker Associates, dated September 15, 2006, for back-up calculations regarding the
storm water treatment unit.
4.5 Construction-Phase BMPs
Additional best management practices to prevent reduce, and/or treat storm water
pollution will be implemented during the construction phase of the project. Because the
site is greater than 1 acre (as required by the NPDES General Permit) and because it is
considered a Medium Priority Construction Project by the City of Carlsbad, a Storm
Water Pollution Prevention Plan (SWPPP) will be developed for the project site under
separate cover and will be incorporated by reference into this document.
La costa Resort - Tentative Map
Planning Area 1, Building 9A-9B, bA-10E 15
Storm Water Management Plan IBF
STORM WATER MANAGEMENT PLAN
5 LOW IMPACT DEVELOPMENT
Low Impact Development (LID) is an alternative method of land development that seeks
to maintain the natural hydrologic character of the site. Per the Draft County of San
Diego Low Impact Development Handbook and in anticipation for the future City of
Carlsbad Municipal Permit LID requirement, LID BMPs have been included as part of
our site design. LID BMPs will collectively minimize directly connected impervious areas
and promote infiltration.
5.1 Pervious Pavement
Pervious pavement will be used in a portion of the parking lot. The advantages of
pervious pavement are that they reduce runoff volume while providing treatment and are
unobtrusive. It is comprised of a permeable surface places over a granular course on
top of a reservoir of large stone. The pervious pavement has been designed according
to the recommendations of the 2003 California New Development BMP Handbook, Fact
Sheet SD-20. Pervious pavement has high removal efficiencies for all potential
pollutants identified for this site.
5.2 Roof Runoff Disconnect
A portion of the roof drainage will drain into pervious areas prior to entering the closed
drainage system. This disconnect allows an opportunity to reduce rate and increase
infiltration at the project site.
5.3 Parking Lot Filter Strips
Based on anticipated pollutants and the primary pollutants of concern, two four-foot wide
filter strips are being incorporated into the parking lot design. The filter strips will utilize
the allowable overhang area for a total width of four feet. The filter strips will be
designed to treat run-off and ultimately connect storm water with the closed drainage
system.
6 MAINTENANCE
To ensure long-term maintenance of project BMPs, the project proponent will enter into
a contract with the City of Carlsbad to obligate the project proponent to maintain, repair
and replace the storm water BMP as necessary into perpetuity. Security will be required
in the form of a Letter of Credit.
The site shall be kept in a neat and orderly fashion with a regularly scheduled landscape
maintenance crew in charge of keeping gutters and inlets free of litter and debris. The
landscape crew will also maintain the landscaping to prevent soil erosion and minimize
sediment transport.
The project consists of a series of catch basins, which will include Kristar Floguard Plus®
inlet inserts. It is recommended that the hydrocarbon absorption booms be replaced
four times per year. Currently the approximate cost to replace each boom is $100.00.
This amounts to a maintenance cost of $400.00 per year, per inlet.
La Costa Resort - Tentative Map
Planning Area 1, Building 9A-9B, bA-10E 16
Storm Water Management Plan
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STORM WATER MANAGEMENT PLAN
Maintenance records shall be retained for at least 5-years. These records shall be made
available to the City of Carlsbad for inspection upon request.
La Costa Resort - Tentative Map
Planning Area 1, Building 9A-9B, bA-10E 17
Storm Water Management Plan WF
* SEE PRELIMINARY HYDROLOGY NARRATIVE FOR DRAINAGE AREAS
(}Aj DFOIMT ION
EXISTING LAM) USE: COMMERCIAL.
PROPOSED LAM) .• CQERCIAL.
GENERAL PLAN DESIGNATION: TRAVEL/RECREATION COMMERCIAL.
ADJACENT LAM) USE COMMERCIAL AND RESIDENTIAL.
ALL STORM DRAIN FACILITIES SIZES AND LOCATION ARE
PRELIMINARY AND SUBJECT TO FINAL I-4YDRU..00Y DESIGN &
ACCEPTANCE IP HYDRAULIC CALCULATIONS BY CITY IP
CARAD.
TOPOGRAPHY PREPARED BY VERTICAL MAPPING RESOURCE. INC.
BENW a&<
A STREET CENTERLINE MONUMENT ON EL CAMINO REAL 0.88 MILES
NORTHERLY FROM LA COSTA AVENUE.
RECORD FROM: NORTH COUNTY VERTICAL CONTROL DATA, PAGE 184.
ELEVATION: 113.122 ADJUSTED
DATUM: NGVV 1929
LEGAL DESCRIPTION
IN TIE CITY OF CARLAD. COUNTY IP SAN DIEGO, STATE IP
CALIFORNIA.,
LOTS 10, 11, 12, AND 16 IP LA COSTA RESORT, CAI8SBAO TRACT
03-01, PER MAP 14984 RECORDED MARCH 18, 2005
PARCEL A, CE 050025, ADU 05-08. RECORDED SEPTEMBER 22.
2005 AS INSTRUMENT NO. 2005-0818754
PARCEL C, CE 050027, ADJ 05-06, RECD SEPTEMBER 22.
2005 AS INSTRUMENT NO. 2005-818756
PARCEL D, CE 050028, AD) 05-08, RECD SEPT04XR 22,
2005 AS INSTRUMENT NO. 2005-818757
P1M1ING AREA 1
M.IER CE LOTS 12
GROSS ACREAGE.' 4.58 AC.
PERCENT IP PROJECT IN STREETS OX
EARTHWORK OUANT ITY ESTIMATE: 5,000 C. Y.
CONTOUR INTERVAL: 1'
OWPER/D.EVEi_OPER
QEVIS lOSEA
*2007 LA COSTA I. LLC
2100 COSTA (X]_ MAR ROAD
CAg..AD, CA 92009
QUINTS
SITE RUNOFF WILL BE DIRECTED AWAY FROM THE TIPS IP
TI...IPES, AND ALL TI.LFES WILL BE VEGETATED TO PROVIDE
PERMANENT STABILIZATION.
kEASJVES WILL BE TAKEN TO EIELBE THE EFFICIENT
APPLICATION IP WATER TO THE LANDSCAPING AND PREVENT ANY
UNNECESSARY RIJF FROM IRRIGATION. SEE SECTION 4.2.1.1.
THERE WILL BE NO (9JTtXIOR MATERIAL STORAGE AREAS
ASSOCIATED WITH THE PROPOSED PROJECT. SEE SECTION 4.2.2.
LEMO
EXIST. CONTOUR
PROPOSED CONTOUR
VEGETATED SLOPES
IMPERVIOUS PAVING I
POROUS PAVEMENT 2292221
BUILDINGS I I
LANDSCAPED ISLANDS
STORM WATER FILTER STRIP
RU' ST(W8I DRAIN
PVC STORM DRAIN
DIRECTION IP FLOW -
EX. CURB INLET--'
ESTRELLA DE MAR ROAD I
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POST-CONSTRUCTION BMP SITE MAP
30 0 30 60 90 LA COSTA RESORT & SPA SCALE 1=30'
PLANNING AREA 1 - BUILDINGS 9A, 9B, 1OA-10E
APPENDIX A
I STORM WATER REQUIREMENTS APPLICABILITY CHECKLIST
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Project Address Assessors Parcel Number(s): Project # (city use only):
216-591-02, 03, 04, 08, 15, 21, 23
Complete Sections 1 and 2 of the following checklist to determine your project's permanent and
construction storm water best management practices requirements. This form must be com
p
l
e
t
e
d
and submitted with your permit application.
Section 1. Permanent Storm Water BMP Requirements:
If any answers to Part A are answered 'Yes," your project is subject to the "Priority
P
r
o
j
e
c
t
Permanent Storm Water BMP Requirements," and "Standard Permanent Storm Water
B
M
P
Requirements" in Section III, "Permanent Storm Water BMP Selection Procedure" in t
h
e
S
t
o
r
m
Water Standards manual.
If all answers to Part A are "No," and Au answers to Part B are "Yes," your project is only subject to the "Standard Permanent Storm Water BMP Requirements". If every question in Part
A
a
n
d
B
is answered "No," your project is exempt from permanent storm water requirements.
Part A Determine Priority Proiect Permanent Storm Water HMP Reaulrements.
Does the project meet the definition of one or more of the priority project categorles?* Yes No
Detached residential development of 10 or more units. Jill E?]
Attached residential development of 10 or more units. LII E?i
Commercial development greater than 100,000 square feet. Jij
Automotive repair shop. Eli II1J
Restaurant. LII Iii
Steep hillside development greater than 5,000 square feet. JlJ EI1
Project discharging to receiving waters within Environmentally Sensitive Areas. flu E!1 Parking lots greater than or equal to 5,000 ft or with at least 15 parking spaces, and
potentially exposed to urban runoff.
Streets, roads, highways, and freeways which would create a new paved surface that is
5,000 square feet or greater * Refer to the definitions section in the Storm Water Standards for expanded definitions of the
priority project categories.
Limited Exclusion: Trenching and resurfacing work associated with utility projects are not
considered priority projects. Parking lots, buildings and other structures associated with util
i
t
y
projects are priority projects if one or more of the criteria in Part A is met. If all answers to
P
a
r
t
A
are "No", continue to Part B.
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Part B: Dtrmina Standard Prmannt Storm Water Rauiremnts.
Does the project propose:
Yes No New impervious areas, such as rooftops, roads, parking lots, driveways, paths a
n
d
sidewalks? Fv(1 EJ
New pervious landscape areas and irrigation systems? J LII Permanent structures within 100 feet of any natural water body? Ii1 Trash storage areas? Elli EI1 Liquid or solid material loading and unloading areas? LI II?J Vehicle or equipment fueling, washing, or maintenance areas? LJ 1I!I Require a General NPDES Permit for Storm Water Discharges Associated with I
n
d
u
s
t
r
i
a
l
-
Activities (Except construction)?*
- - Commercial or industrial waste handling or storage, excluding typical office or hous
e
h
o
l
d
waste?
Any grading or ground disturbance during construction? F/1, F 1
Any new storm drains, or alteration to existing storm drains? IJ U *To find out if your project is required to obtain an individual General NPDES Permit
f
o
r
S
t
o
r
m
W
a
t
e
r
Discharges Associated with Industrial Activities, visit the State Water Resources Co
n
t
r
o
l
*Board web site at, www.swrcb.ca.gov/stormwtr/industrial.html
Section 2.
Construction Storm Water BMP Requirements:
If the answer to question I of Part C is answered 'Yes," your project is subject t
o
S
e
c
t
i
o
n
I
V
,
"
C
o
n
s
t
r
u
c
t
i
o
n
Storm Water BMP Performance Standards," and must prepare a Storm Water
P
o
l
l
u
t
i
o
n
P
r
e
v
e
n
t
i
o
n
P
l
a
n
(SWPPP). If the answer to question 1 is "No," but the answer to any of the rema
i
n
i
n
g
q
u
e
s
t
i
o
n
s
i
s
'
Y
e
s
,
"
your project is subject to Section IV, "Construction Storm Water BMP Performan
c
e
S
t
a
n
d
a
r
d
s
,
"
a
n
d
m
u
s
t
prepare a Water Pollution Control Plan (WPCP). If every question in Part C is a
n
s
w
e
r
e
d
"
N
o
,
"
y
o
u
r
p
r
o
j
e
c
t
is exempt from any construction storm water BMP requirements. If any of the ans
w
e
r
s
t
o
t
h
e
q
u
e
s
t
i
o
n
s
i
n
Part C are 'Yes," complete the construction site prioritization in Part D, below.
Part C: Determine Construction Phase Storm Water Requirements.
Would the project meet any of these criteria during construction?
Yes No Is the project subject to California's statewide General NPDES Permit for Storm
W
a
t
e
r
Discharges Associated With Construction Activities?
Does the project propose grading or soil disturbance? jJ Would storm water or urban runoff have the potential to contact any portion of t
h
e
constructionarea, including washing and staging areas?
EJ-1
Would the project use any construction materials that could negatively affect water qu
a
l
i
t
y
if discharged from the site (such as, paints, solvents, concrete, and stucco)?
- I
I
Part D: Determine Construction Site Priority
In accordance with the Municipal Permit, each construction site wit
h
c
o
n
s
t
r
u
c
t
i
o
n
s
t
o
r
m
w
a
t
e
r
B
M
P
requirements must be designated with a priority: high, medium or
l
o
w
.
T
h
i
s
p
r
i
o
r
i
t
i
z
a
t
i
o
n
m
u
s
t
b
e
completed with this form, noted on the plans, and included in the SWP
P
P
o
r
W
P
C
P
.
I
n
d
i
c
a
t
e
t
h
e
p
r
o
j
e
c
t
'
s
priority in one of the check boxes using the criteria below, and existin
g
a
n
d
s
u
r
r
o
u
n
d
i
n
g
c
o
n
d
i
t
i
o
n
s
o
f
t
h
e
project, the type of activities necessary to complete the const
r
u
c
t
i
o
n
a
n
d
a
n
y
o
t
h
e
r
e
x
t
e
n
u
a
t
i
n
g
circumstances that may pose a threat to water quality. The City res
e
r
v
e
s
t
h
e
r
i
g
h
t
t
o
a
d
j
u
s
t
t
h
e
p
r
i
o
r
i
t
y
'
o
f
the projects both before and during construction. [Note: The co
n
s
t
r
u
c
t
i
o
n
p
r
i
o
r
i
t
y
d
o
e
s
N
O
T
c
h
a
n
g
e
construction BMP requirements that apply to projects; all cons
t
r
u
c
t
i
o
n
B
M
P
r
e
q
u
i
r
e
m
e
n
t
s
m
u
s
t
b
e
identified on a case-by-case basis. The construction priority does affect
t
h
e
f
r
e
q
u
e
n
c
y
o
f
i
n
s
p
e
c
t
i
o
n
s
t
h
a
t
will be conducted by City staff. See Section lV.1 for more details on
c
o
n
s
t
r
u
c
t
i
o
n
B
M
P
r
e
q
u
i
r
e
m
e
n
t
s
.
]
fjA) 1-ugh Priority
Projects where the site is 50 acres or more and grading will occur durin
g
t
h
e
r
a
i
n
y
s
e
a
s
o
n
Projects I acre or more.
Projects 1 acre or more within or directly adjacent to or discharging directly to
a
c
o
a
s
t
a
l
l
a
g
o
o
n
o
r
other receiving water within an environmentally sensitive area
Projects, active or inactive, adjacent or tributary to sensitive water bodies
LI B) Medium Priority
Capital Improvement Projects where grading occurs, however a St
o
r
m
W
a
t
e
r
P
o
l
l
u
t
i
o
n
P
r
e
v
e
n
t
i
o
n
Plan (SWPPP) is not required under the State General Constructi
o
n
P
e
r
m
i
t
(
i
.
e
.
,
w
a
t
e
r
a
n
d
s
e
w
e
r
replacement projects, intersection and street re-alignments, widenin
g
,
c
o
m
f
o
r
t
s
t
a
t
i
o
n
s
,
e
t
c
.
)
Permit projects in the public right-of-way where grading occurs, s
u
c
h
a
s
'
i
n
s
t
a
l
l
a
t
i
o
n
o
f
s
i
d
e
w
a
l
k
,
substantial retaining walls, curb and gutter for an entire street fronta
g
e
,
e
t
c
.
, however SWPPPs are not required.
Permit projects on private property where grading permits are requi
r
e
d
,
h
o
w
e
v
e
r
,
N
o
t
i
c
e
O
f
I
n
t
e
n
t
s
(NO Is) and SWPPPs are not required.
LI C) LowPriority
Capital Projects where minimal to no grading occurs, such as signal
l
i
g
h
t
a
n
d
l
o
o
p
i
n
s
t
a
l
l
a
t
i
o
n
s
,
street light installations, etc.
Permit projects in the public right-of-way where minimal to no gra
d
i
n
g
o
c
c
u
r
s
,
s
u
c
h
a
s
p
e
d
e
s
t
r
i
a
n
ramps, driveway additions, small retaining walls, etc.
Permit projects on private property where grading permits are not req
u
i
r
e
d
,
s
u
c
h
a
s
s
m
a
l
l
'
r
e
t
a
i
n
i
n
g
walls, single-family homes, small tenant improvements, etc.
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Storm Water Standards
4/03/03
APPENDIX B
DRAFT
ENVIRONMENTALLY SENSITIVE AREAS WITHIN THE CITY OF CARLSBAD
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APPENDIX B
BMP CALCULATIONS
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Targeted Constituents
IJ Sediment
l?I Nutrients
RI Trash
RI Metals
Bacteria
E1 Oil and Grease
Organics
Removal Effect!veness
See New Development and
Redevelopment Handbook-Section 5.
Drain Inserts MP-52
Design Considerations
i Usewith other BMPs
i Fit and Seal Capacity within Inlet
I
Description
Drain inserts are manufactured filters or fabric placed in a drop
inlet to remove sediment and debris. There are a multitude of
inserts of various shapes and configurations, typically falling into
one of three different groups: socks, boxes, and trays. The sock
consists of a fabric, usually constructed of polypropylene. The
fabric may be attached to a frame or the grate of the inlet holds
the sock. Socks are meant for vertical (drop) inlets. Boxes are
constructed ofplastic or wire mesh. Typically a polypropylene
"bag" is placed in the wire mesh box. The bag takes the form of
the box. Most box products are one box; that is, the setting area
and filtration through media occur in the same box. Some
products consist of one or more trays or mesh grates. The trays
may hold different types of media. Filtration media vary by
manufacturer. Types include polypropylene, porous polymer,
treated cellulose, and activated carbon.
California Experience
I The number of installations is unknown but likely exceeds a
thousand. Some users have reported that these systems require
considerable maintenance to prevent plugging and bypass.
I Advantages
Does not require additional space as inserts as the drain
I inlets are already a component of the standard drainage
systems. ' U Easy access for inspection and maintenance.
As there is no standing water, there is little concern for
- mosquito breeding.
A relatively inexpensive retrofit option.
I Limitations
Performance is likely significantly less than treatment systems
that are located at the end of the drainage system such as ponds
I and vaults. Usually not suitable for large areas or areas with
trash or leaves than can plug the insert.
I Design and Sizing Guidelines
Refer to manufacturer's guidelines. Drain inserts come any
many configurations but can be placed into three general groups:
I socks, boxes, and trays. The sock consists of fabric, usually
constructed of polypropylene. The fabric may be attached to a
frame or the grate of the inlet holds the sock. Socks are meant
I for vertical (drop) inlets. Boxes are constructed of plastic or wire
mesh Typically a polypropylene "bag" is placed in the wire mesh
box The bag takes the form of the box Most box products are
CAUR1(NL. JQ1MrER
I January 2003 California Stormwater BMP Handbook 1 of 3 New Development and Redevelopment
MP-52 Drain Inserts
one box; that is, the setting area and filtration through media occurs in the same box. One
manufacturer has a double-box. Storinwater enters the first box where setting occurs. The
stonnwater flows into the second box where the filter media is located. Some products consist
of one or more trays or mesh grates. The trays can hold different types ofmedia. Filtration
media vary with the manufacturer: types include polypropylene, porous polymer, treated
cellulose, and activated carbon.
Construction/Inspection Considerations
Be certain that installation is done in a manner that makes certain that the stormwater enters
the unit and does not leak around the perimeter. Leakage between the frame of the insert and
the frame of the drain inlet can easily occur with vertical (drop) inlets.
Performance
Few products have performance data collected under field conditions.
Siting Criteria
It is recommended that inserts be used only for retrofit situations or as pretreatment where
other treatment BMPs presented in this section area used.
Additional Design Guidelines
Follow guidelines provided by individual manufacturers.
Maintenance
Likely require frequent maintenance, on the order of several times per year.
Cost
The initial cost of individual inserts ranges from less than $100 to about $2,000. The cost of using multiple units in curb inlet drains varies with the size of the inlet.
The low cost of inserts may tend to favor the use of these systems over other, more effective
treatment BMPs. However, the low cost of each unit may be offset by the number of units
that are required, more frequent maintenance, and the shorter structural life (and therefore
replacement).
References and Sources of Additional Information
Hrachovec, R., and G. Minton, 2001, Field testing of a sock-type catch basin insert, Planet CPR, Seattle, Washington
Interagency Catch Basin Insert Committee, Evaluation of Commercially-Available Catch Basin
Inserts for the Treatment of Stormwater Runoff from Developed Sites, 1995
Larry Walker Associates, June 1998, NDMP Inlet/In-Line Control Measure Study Report
Manufacturers literature
Santa Monica (City), Santa Monica Bay Municipal Stormwater/Urban Runoff Project
- Evaluation of Potential Catch basin Retrofits, Woodward Clyde, September 24, 1998
2 of 3 California Stormwatr BMP Handbook January 2003 New Development and Redevelopment
Drain Inserts MP-52
Woodward Clyde, June ii, 16, Parking Lot Monitoring Report, Santa Clara Valley Nonpoint Source Pollution Cont±ol Program.
January 2003 California Stormwater BMP Handbook 3 of 3 New Develonment and Rtevpfnnment-
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Model No.
I Inlet ID
(in x in)
Grate OD
. (in x in)
I.Solids Storage
Capacity (Cu if)
Filtered Flow
(cf)
Total Bypass
. Cap. (cf)
FGP-12F 1.12x 12 1 .14 x 14 1 .0.3 .0.4 2.8
FGP-1530F .15 x 30 .16 x 36 2.3 1.6 .6.9
FG13-16F j6x 16 .18x18 .0.8 0.7 4.7
FGP.18F .18x 18 20 x20 0.8 .0.7 4.7
FGP-1822F 20 x 24 .18 x22 2.1 .1.4 5.9
FGP4824F .16 x 22 20 x24 .1.5 1.2 .5.0
FGP4836F .18 x 36 .18x40 2.3 .1.6 .6.9 .6
FGP-2024F 20 x 24 22 x.24 .1.2 .1.0 .5.9
FGP-21F 22 x 22 24 x 24 22 .1.5 6.1
FGP-2142F 21 x 42 26 x 42 4.3 2.4 .9.1
FGP-24F 24 x 24 26 x 28 2.2 .1.5 5.1
FGP-2436F 24 x 36 24 x 40 3.4 2.0 .8.0
FGP-2445F 24 *45 26 x 47 4.4 2.4 .9.3
FGP-2448F 24 x48 26 x 48 4.4 1 2.4 .9.3
FGP-28F 28x28 30x30 . 2.2 1 .1.5 .6.3
FGP-30F .30 x 30 .30 x 34 .3.6 . 2.0 .8.1
FGP-.36F .36x36 .36x40 4.6 24 .9.1
FGP4648F
148x48
.36x48 40x48 . .6.8 3.2 .11.5
FGP.48F 48 x 52 .9.5 3.9 .132
III
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Flo-Gard+Plus Filtei
installed
NOTES:
.t Storage capacity reflects 80% of maximum solids
collection Prior to Impeding littering bypass.
Filtered flow rate Includes a safety factor of 2.
Flo-Gard+Ptus Catch Basin Fitter Inserts are available
In the standard sizes (see above) or In custom sizm
ceti for details on custom size Inserts.
.4. Flo-GardPIus litter Inserts should be used In conjunction
with a regular maintenance program Refer to
mantfacture?s recommended maintenance guidelines.
US PATENT
III
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FLO-GARIf4+PLUS
CATCH BASIN FILTER INSERT
(Frame Mount)
FLAT GRATED INLET
J<riStar Enterprises, Inc., Santa Rosa, CA (800) 579-8819
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Targeted Constituents
0 Sediment A
Il Nutrients;
I1 Trash
Metals
Bacteria
Rf Oil and Grease
E1 Organics
Legend (Removal Effectiveness)
S Low I High
A Medium
LUUX.\IA 1O1O 1YAIE}(
1 of 5
I Vortex Separator MP5 1
I Description
Vortex separators: (alternatively, swirl concentrators) are gravity
separators, and in principle are essentially wet vaults. The I .
difference from wet vaults, however, is that the vortex separator
is round, rather than rectangular, and the water moves in a
centrifugal fashion before exiting. By having the water move in a I circular fashion, rather than a straight line as is the case with a
standard wet vault it is possible to obtain significant removal of
suspended sediments and attached pollutants with less space. I Vortex separators were originally developed for combined sewer
overflows (CSOs), where it is used priinarilyto remove coarse
inorganic solids. Vortex separation has been adapted to I stormwater treatment by several manufacturers.
California Experience
I There are currently about 100 installations in California.
Advantages
I . May provide the desired performance in less space and
therefore less cost.
I May be more cost-effective pre-treatment devices than
traditional wet or dry basins.
I . Mosquito control may be less of an issue than with traditional
wet basins.
I .
Limitations
As some of the systems have standing water that remains
- between storms, there is concern about mosquito breeding.
1 . it is likely that vortex separators are not as effective as wet
vaults at removing fine sediments, on the order 50 to 100
I
microns in diameter and less.
limited . The area served is by the capacity of the largest
models.
Design Considerations
. Service Area
Settling Velocity
. Appropriate Sizing
Inlet Pipe Diameter
. As the products come in standard sizes, the facilities will be
oversized in many cases relative to the design treatment
storm, increasing the cost.
. The non-steady flows of stormwater decreases the efficiency
of vortex separators from what maybe estimated or
determined from testing under constant flow.
. Do not remove dissolved pollutants.
January 2003 California StormwatorBMP Handbook
New DevcInnmc'nf A nr .-'-'-'-'-
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I MP-51 Vortex Separator
A loss of dissolved pollutants may occur as accumulated organic matter (e.g., leaves)
decomposes in the units.
I Design and Sizing Guidelines
The sto rmwater enters, typically below the effluent lirie, tangentially into the basin, thereby
I
imparting a circular motion in the system. Due to centrifugal forces created by the circular
motion, the suspended particles move to the center of the device where they settle to the bottom.
There are two general types of vortex separation: free vortex and dampened (or impeded)
vortex Free vortex separation becomes dampened vortex separation by the placement of radial
I baffles on the weir-plate that impede the free vortex-flow pattern
It has been stated with respect to CSOs that the practical lower limit of vortex separation is a
I particle with a settling velocity of 12 to 16.5 feet per hour (0.10 to 0.14 cm/s). As such, the focus for vortex separation in CSOs has been with settleable solids generally 200 microns and large; given the presence of the lighter organic solids. For inorganic sediment, the above settling
I velocity range represents a particle diameter of 50 to ioo microns. Head loss is a function of the size of the target particle. At 200 microns it is normally minor but increases significantly if the goal is to remove smaller particles.
The commercial separators applied to stormwater treatment vary considerably with respect to
geometry, and the inclusion of radial baffles and internal circular chambers. At one extreme is
I the inclusion of a chamber within the round concentrator. Water flows initially around the
perimeter between the inner and outer chambers, and then into the inner chamber, giving rise
to a sudden change in velocity that purportedly enhances removal efficiency. The opposite
I
extreme is to introduce the water tangentially into a round manhole with no internal parts of
any kind except for an outlet hood. Whether the inclusion of chambers and baffles gives better
performance is unknown. Some contend that free vortex, also identified as swirl concentration,
creates less turbulence thereby increasing removal efficiency. One product is unique in that it
I includes a static separator screen.
Sized is based on the peak flow of the design treatment event as specified by local
I government.
If an in-line facility, the design peak flow is four times the peak ofthe design treatment
I event.
If an off-line facility, the design peak flow is equal to the peak of the design treatment event.
1 • Headloss differs with the product and the model but is generally on the order of one foot or
less in most cases.
I Construction/Inspection Considerations
No special considerations.
I Performance
Manufacturer's differ with respect to performance claims, but a general statement is that the
manufacturer's design and rated capacity (cfs) for each model is based on and believed to
I achieve an aggregate reduction of 90% of all particles with a specific gravity of 2.65 (glacial sand) down to 150 microns, and to capture the floatables, and oil and grease. Laboratory tests of
2 of 5 California Stormwatr BMP Handbook January 2003 New Devetonrnpnl-intl
Vortex Separator MP-51
two products support this claim. The stated performance expectation therefore implies t
h
a
t
a
lesser removal efficiency is obtained with particles less than 150 microns, and the lighter, organic settleables. Laboratory tests of one of the products found about 6o% removal of
50 micron sand at the expected average operating flow rate
Experience with the use of vortex separators for treating combined sewer overflows (CSOs
)
,
t
h
e
original application of this technology, suggests that the lower practical limit for particle
removal are particles with a settling velocity of 12 feet per hour (Sullivan, 1982), which represents a particle diameter of ioo to 200 microns, depending on the specific gravity of the particle. The CSO experience therefore seems consistent with the limited experience with
treating stormwater, summarized above
Traditional treatment technologies such as wet ponds and extended detention basins are
generally believed to be more effective at removing very small particles, down to the range of
10 to 2o microns. Hence, it is intuitively expected that vortex separators do not perform as well as
the traditional wet and dry basins, and filters. Whether this matters depends on the particle s
i
z
e
distribution of the sediments in stormwater. If the distribution leans towards small material,
there should be a marked difference between vortex separators and, say, traditional wet vaults.
There are little data to support this conjecture
In comparison to other treatment technologies, such as wet ponds and grass swales, there are
few studies of vortex separators. Only two of manufactured products currently available have
been field tested. Two field studies have been conducted. Both achieved in excess of 80%
removal of TSS. However, the test was conducted in the Northeast (New York state and M
a
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e
)
where it is possible the stormwater contained significant quantities of deicing sand.
Consequently, the influent TSS concentrations and particle size are both likely considerably
higher than is found in California stormwater. These data suggest that if the stormwater
particles are for the most part fine (ie., less than 50 microns), vortex separators will not be as efficient as traditional treatment BMPs such as wet ponds and swales, if the latter are sized
according to the recommendations of this handbook.
There are no equations that provide a straightforward determination of efficiency as a functi
o
n
of unit configuration and size. Design specifications of commercial separators are derived fr
o
m
empirical equations that are unique and proprietary to each manufacturer. However, some
general relationships between performance and the geometry of a separator have been
developed. CSO studies have found that the primary determinants of performance of vortex
separators are the diameters of the inlet pipe and chamber with all other geometry proportiona
l
to these two.
Sullivan et al. (1982) found that performance is related to the ratios of chamber to inlet
diameters, D2/D1, and height between the inlet and outlet and the inlet diameter, Hi/Di, shown
in Figure 3. The relationships are: as D2/D1 approaches one, the efficiency decreases; and, as the Hi/Di ratio decreases, the efficiency decreases. These relationships may allow qualitati
v
e
comparisons of the alternative designs of manufacturers. Engineers who wish to apply thes
e
concepts should review relevant publications presented in the References.
Siting Criteria
There are no particularly unique siting criteria The size of the drainage area that can be serve
d
by vortex separators is directly related to the capacities of the largest models.
January 2003 CaIiforna Stormwater BMP Handbook
3 of 5 New Development and Redevelopment
i MP-51 Vortex Separator
1 Additional Design Guidelines
Vortex separators have two capacities if positioned as in-line facilities, a treatment capacity and
I
a hydraulic capacity. Failure to recognize the difference between the two may lead to significant
under sizing; ie., too small a model is selected. This observation is relevant to three of the five
products. These three technologies all are designed to experience a unit flow rate of about 24
I
. gallons/square foot of separator footprint at the peak of the design treatment event. This is the
horizontal area of the separator zone within the container, not the total footprint of the unit. At
this unit flow rate, laboratory tests by these manufacturers have established that the
I
performance will meet the general claims previously described. However, the units are sized to
handle 100 gallons/square foot at the peak of the hydraulic event. Hence, in selecting a
particular model the design engineer must be certain to match the peak flow of the design event
to the stated treatment. capacity, not the hydraulic capacity. The former is one-fourth the latter.
If the unit is positioned as an off-line facility, the model selected is based on the capacity equal
to the peak of the design treatment event.
I. Maintenance
Maintenance consists of the removal of accumulated material with an eductor truck. It may be
necessary to remove and dispose the floatables separately due to the presence of petroleum
I product.
Maintenance Requirements
I Remove all accumulated sediment; and litter and other floatables, annually, unless experience
indicates the need for more or less frequent maintenance.
I Cost
Manufacturers provide costs for the units including delivery. Installation costs are generally on
the order of 50 to 100 % of the manufacturer's cost. For most sites the units are cleaned
I annually.
Cost Considerations
I The different geometry of the several manufactured separators suggests that when comparing
the costs of these systems to each other, that local conditions (e.g., groundwater levels) may
affect the relative cost-effectiveness.
I References and Sources of Additional Information
Field, R., 1972, The swirl concentrator as a combined sewer overflow regulator facility, EPA/R2-
I
-oo8, U.S. Environmental Protection Agency, Washington, D.C.
Field, R., D. Averiii, T.P. O'Connor, and P. Steel, 1997, Vortex separation technology, Water
I
Qual. Res. J. Canada, 32, 1,185
Manufacturers technical materials
I. Sullivan, R.H., et al., 1982, Design manual -swirl and helical bend pollution control devices,
EPA-600/8-82/013, U.S. Environmental Protection Agency, Washington, D.C.
I
Sullivan, R.H., M.M. Cohn, J.E. Ure, F.F. Parkinson, and G. CaBana, 1974, Relationship between diameter and height for the design of a swirl concentrator as a combined sewer over
regulator, EPA 670/2-74-039, U.S. Environmental Protection Agency, Washington, D.C.
4 of 5 California Stormwater BMP Handbook January 2003 New Development and RjeveIonmnt-
Vortex Separator MP-51
I Sullivan, R.H., M.M. Cohn, J.E. lire, F.F. Parkinson, and G. Caliana, 1974, The swirl' concentrator as a grit separator device, EPA670/2-74-026, U.S. Environmental Protection
Agency, Washington, D.C.
I Sullivan, R.H., M.M. Cohn, J.E. lire, F.F. Parkinson, and G. Caliana, 1978, Swirl primary separator device and pilot demonstration, EPA600/2-78-126, U.S. Environmental Protection
Agency, Washington, D.C.
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1 January 2003 California Stnrmwater BMP Handbook 5 of 5 New Development and Redevelopment
Targeted Constituents
[?I Sediment A
21 Nutrients
El Trash
El Metals A
El Bacteria
El Oil and Grease A
El Organics A
El Oxygen Demanding A
Legend (Removal Effectiveness)
Low IN High
A Medium
Vegetated Swale
General Description
Vegetated swales are open, shallow channels with vegetation
eoverig the side slopes and bottom that collect and slowly
convey runoff flow to downstream discharge points. They are
designed to treat runoff through filtering by the vegetation in the
hann.J, filtering through a subsoil matrix, and/or infiltration
into the underlying soils. Swales can be natural or manmade.
They trap particulate pollutants (suspended solids and trace
metals), promote infiltration, and reduce the flow velocity of
stormwater runoff. Vegetated swales can serve as part of a
storrnwater drainage system and can replace curbs, gutters and
storm sewer systrms. Therefore, swales are best suited for
residential, industrial, and commercial areas with low flow and
smaller populations.
Inspection/Maintenance Considerations
It is important tc consider that a thick vegetative cover is needed
for vegetated swales to function properly. Usually, swales
require little more than normal landscape maintenance activities
such as irrigation and mowing to maintain pollutant removal
efficiency. Swale scan 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. The application of
fertilizers and pesticides should be minimized.
TC-30
Maintenance Concerns,
Objectives, and Goats
. Channelization
is Vegetation/Landscape
Maintenance
Vector Control
Aesthetics
Hydraulic and Removal Efficacy
P1
Ianuary 2003 California Stormwater BMP Handbook 1 of 3
Municipal
www.ca bmpha ndbooks.com
I
i TC-30 Vegetated Swale
q
---'.-- - .-.-
FPost Inspect after seeding and after first major storms for any damages. onstruction
Inspect for signs of erosion, damage to vegetation, channelization of flow, debris and Semi-annual I. lifter, and areas of sediment accumulation. Perform inspections atthe beginning and end
of the wet season. Additional inspections after periods of heavy runoff are desirable.
Inspect level spreader for clogging, grass along side slopes for erosion and formation of Annual I N
rills orgullies, and sand/soil bed for erosion problems.
- - •'--
.FYT: Sunn.stëd
•
I
Vt4antenanieActivitiês
...................-
----- -: .. - .;_
-- - -
--'. Frequency ..:i
Mow grass to maintain a height 0f3-4 inches, for safety, aesthetic, or other purposes. As needed
Litter should always be removed prior to mowing. Clippings should be composted. (frequent,
I N Irrigate swale during dry season (April through October) or when necessary to maintain seasonally)
the vegetation.
N Provide weed control, if necessary to control invasive species.
I • Remove lifter, branches, blockages, rocks and other debris and dispose of properly. Semi-annual
N Maintain inlet flow spreader (if applicable).
I N Repair any damaged areas within a channel identified during inspections. Erosion ruts or
gullies should be corrected as needed. Bare areas should be replanted as necessary.
I N Declog the pea gravel diaphragm, if necessary. Annual (as needed)
N Correct erosion problems in the sand/soil bed of dry swales.
Plant an alternative grass species if the original grass cover has not been successfully I established. Reseed and apply mulch to damaged areas.
Remove all accumulated sediment that may obstruct flow through the swale. Sediment As needed
accumulating near culverts and in channels should be removed when it builds up to 3 in. (infrequent) I at any spot, or covers vegetation, or once it has accumulated to 10% of the original design
volume. Replace the grass areas damaged in the process.
Rototill or cultivate the surface of the sand/soil bed of dry swales if the swale does not
draw down within 48 hours.
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I 2 of 3 California Stormwater BMP Handbook January 2003
Municipal
www.cabmnhandhnnkc rr,m
1
i Vegetated Swale TCN30
I Additional. Information
Recent research (Colwell et al, 2000) indicates that grass height and mowing frequency have
little impact on pollutant removal. Consequently, mowing may only be necessary once or twice a
I year for safety or aesthetics or to suppress weeds and woody vegetation.
References
I: .Metropolitan Council, Urban Small Sites Best Management Practices Manual. Available at:
http://www.metrocouncilorg/environment/watershed/BMp/manual.htm
I. U.S. Environmental Protection Agency, Post-Construction Stormwater Management in New
Development & Redevelopment BMP Factsheets. Available at:
efpub.epa.gov/Lipdesjstormwater/menuofbn1DSj?MP file s.cfrn
I Ventura Countywide Stormwater Quality Management Program, Technical Guidance Manual
for Stormwater Quality Control Measures. July, 2002.
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I January 2003 California Stormwater BMP Handbook 3 of 3
Municipal
www.cabmphandbooks.com
I APPENDIX C
DRAINAGE NARRATIVE
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CONSULTING
March 27, 2008 JN 55-100221.021
Engineering Department
City of Carlsbad
1635 Faraday Avenue
Carlsbad, CA 92008
Subject: Drainage Summary for Planning Area #1 - Building 9 & 10 Parcel Map at the
La Costa Resort & Spa
To Whom It May Concern:
The proposed development for the Planning Area #1 - Building 9 project located at La Costa
Resort, proposes construction of resort villas within Planning Area 1. The site plan has been
modified slightly since Hunsaker & Associates completed the previous analysis. The previous
design planned two buildings with underground parking and a common area. The revised
design proposes seven, two and three story, commercial dwelling buildings (attached and
detached) with two surface parking lots. The purpose of the attached calculations is to
determine if the proposed conditions analyzed in the Drainage Report prepared by Hunsaker &
Associates, dated September 15, 2006 (Reference 2) are valid for the revised site plan of
Planning Area 1.
It was concluded that this project will not significantly alter drainage patterns as those depicted in
the "Drainage Study for La Costa Resort and Spa" (Reference 2), nor adversely effect runoff
quantities since pre and post development 'C" factors are the same. Should you have any
questions or comments regarding this issue, please call (760) 603-6243.
Regards, A.
( C6O28
EV
Timothy M. Thiele, P.E.
Project Engineer
- p
H:\PDATA\551O0221Admin\correspndnc\221It017Phase5TM0rainage.doc
PLANNING U DESIGN I CONSTRUCTION
5050 Avenida Encinas, Suite 260, Carlsbad, CA 92008-4386 • 760.476.9193 • Fax 760.476.9198
Offices located throughout California, Arizona & Nevada U www.RBF.com
Printed on recycled paper
LI Planning Area 1 is located at the southeast corner of Arenal Road and Estrella Del Mar
Road. The major drainage patterns do not change from the previously analyzed
proposed conditions. The southeast corner of the site discharges to the east towards
the existing Golf Rooms and is captured by the existing storm drain system. The
remainder of the site drains southwesterly discharging to an existing inlet structure on
Estrella Del Mar Road. The area draining towards Estrella De Mar Road discharges at
design nodes 510 and 511, as assigned by Reference 2. Also contributing to these
design nodes is a portion of the offsite tributary north of the La Costa Villas project
(approximately 3.0 ac), as captured by design node 203.
Per 2003 County of San Diego criteria, and as consistent with Reference 2, the runoff
coefficients assigned were 0.82 for the commercial areas.
The peak flows were calculated at these nodes to ensure the modified site plan would
not negatively affect the overall drainage system, see appendix A. The table below
summarizes the change in cumulative 100 year peak discharge for the nodes affected by
the design change.
Cumulative 100 Year Peak I
Discharge (cfs) per Cumulative 100 Year Peak
Hunsaker & Associates Discharge (cfs) per revised
Drainage Report Site Plan
(Reference 2)
Node 203 6.74 6.74
Street Flow 7.02 7.02
Node 510 14.87 16.4
Node 511 22.28 20.1
Peak flow rates listed were generated based on criteria set forth in the "2003 San Diego
County Hydrology Manual" Rational Method calculations are located in Appendix A.
Watershed delineations and node locations are visually depicted on the hydrology
exhibits, also located within Appendix A.
References
County of San Diego Design Hydrology Manual, June 2003
"Drainage Study for La Costa Resort & Spa' Hunsaker & Associates San Diego, Inc.,
September 2006.
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I APPENDIX D
APPROVED STORM WATER MANAGEMENT PLAN I
1
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TABLE OF CONTENTS
PAGES
VICINITYMAP .......................................................................................................................... 1
INTRODUCTION..........................................................................................................................2
PROJECT DESCRIPTION .............................................................................................................
POLLUTANTS AND CONDITIONS OF CONCERN ......................................................... . ...... 5
PERMANENT STORM WATER BEST MANAGEMENT PRACTICES .................................. 6
OPERATION AND MAINTENANCE PLAN ......................... . ..... ............................................. ..8
SUMMARY........................................................................................................................
.......... 9
APPENDICES
STORM WATER REQUIREMENT APPLICABILITY CHECKLIST
TABLES FROM THE CITY OF CARLSBAD STORM WATER STANDARDS MANUAL
CALCULATIONS FOR ONSITE WATER QUALITY TREATMENT FLOW REQUIREMENTS AND WATER QUALITY TREATMENT PRODUCT I INFORMATION
MAP POCKETS
1. WATER QUALITY SITE PLAN EXHIBIT FOR LA COSTA RESORT AND SPA MASTER PLAN AMENDMENT
- Mayl,2003
- Revised: November 3, 2003
RC:rh\141 07\Study\ Water Quality Impact Master-Plan (002)
INTRODUCTION
This Storm Water Management Plan (SWMP) describes the permanent Stoma Water Best
Management Practice (BMPs) recommended to be implemented for the La Costa Resort and Spa
Master Plan Amendment project, that satisfy the requirements identified in the following
documents:
-
State Water Resources Control Board (SWRCB) Order No. 99-08-DWQ, National
Pollutant Discharge Elimination System (NPDES) General Permit No. CAS 000062 for
Discharges of Stoma Water Runoff Associated With Construction Activity.
San Diego Region Municipal NPDES Storm Water Permit, Order Number 2001-01
(Municipal Permit).
City of Carlsbad Standard Urban Storm Water Mitigation Plan (SUSMP), Storm Water
Standards Manual dated April 2003.
Included in this report are the preliminary storm runoff calculations necessary to size the
proposed BMPs, the BMP sizing calculations, technical information for the proposed BMPs and
a discussion on the operation and maintenance requirements for the permanent BMPs.
I May!, 2003 U 2 Revised: November 3, 2003
RC:rhU4107kSLudy\Water Oualltv rmoact Macter PI,n (())7
serve to discharge storm runoff into the 36-inch RCP public storm drain system (crossing under
El Camino Real), located northeast of the intersection of El Carnino Real and Costa Del Mar
Road and the existing storm drain system located at the westerly end of Costa Del Mar Road.
May I, 2003 4 Revised: November 3 2003
RC:thU4 107Study\ Water Quality Impact Master Plan (002)
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I
PERMANENT STORM WATER BEST MANAGEMENT PRACTICES
The .Municipal Pennit and the City Storm Water Standards require the implementation of
.applicable site design, source control, project specific, and treatment control BMPs. To ñaeet
these requirements, the project will incorporate a series of non-structural and structural BMIPs to
the maximum extent practicable (IvLEP).
A detailed description of each type of BMP is discussed below:
Site Design BMPs
The following-site design BMPs have been applied:
Minimize the impervious footprint by increasing building density while decreasing
building footprint.
Minimize directly connected inpervious areas to the maximum extent practicable.
Avoid draining water over tops of slopes in order to minimize erosion.
Source Control BMPs
Source control BMPs are generally non-structural and are intended to reduce the quantity of
pollutants entering the storm drain system. 'The following source control BMPs are proposed to
be utilized for the L. Costa Reort and Spa Master Plan Amendment project:
Trash storage areas to be paved with an impervious surface, designed to' -prevent
offsite transport of trash.
Pest resistant plants will be planted to reduce the need for pesticides,
An efficient irrigation system will be installed within the landscaped areas that
addresses the specific waterreqiiirements for-those landscaped areas.
Concrete stamping or stenciling of inlets and catch basins.
Distribution integrated pest management education materials to future site tenants.
May 1. 2003 6 - Revised November 3. 2003 RC:rhk[4 101\Study\Water Quality Imoact Master Plan (0021
'r
1 Zi OPERATION AND MAINTENANCE PLAN
Ir I KSL La Costa Resort Corporation, a Delaware corporation, will construct the improvements
proposed for the La Costa Resort and Spa Master Plan Amendment and shall be required to
maintain all BMPs on the site.
I .
.
I
.The site shall be kept in a neat and orderly fashion with a regularly scheduled landscape
maintenance crew in charge of keeping gutters. and inlets free of litter and debris. The landscape
I . crew will also maintain the landscaping to prevent soil erosion and minimize sediment transport.
F
I . Inlet stamps shall be inspected and reapplied as needed.
The project consists of three proposed and three existing type 'B' curb inlets, which will include
bio-clean filter inserts. Bio-Clean Environmental Services recommends replacement of the
I hydrocarbon absorption boom four times. per year. Currently the approximate ost to replace
each boom is $80.00. This amounts to a maintenance cost of approximately $320.00 per year,
I per inlet. . .
I The proposed project will utilize one CDS Technologies Storm Water Treatment Unit.
Currently, the approximate maintenance cost for one CDS Technologies Unit is $4,500.00 per I year which includes $300.0O'per hourfor labor with a 4-hour minimum and a $300.00 waste
disposal fee per maintenance service for the unit. The maintenance cost assumes that the CDS
Technologies Units are serviced three times a year. These are preliminary costs.
1 KSL La Costa Resort Corporation shall retain maintenance records of at least 5-years, which 1 shall be made available to the City of San Diego for inspection upon request.
$
I .
May 1, 2003 I . .. 8 Revised: November 3. 2003 RC:rh\14 107\S rudy\ Water Quality Impact Master Plan (002)
APPENDIX A
STORM WATER REQUIREMENTS APPLICABILITY CHECKLIST
Storm Water Standards
4/03/03
Section 2. Construction Storm Water BMP.Requirernénts:
If the answer to question 1 of Part C is answered "Yes," your project is subject to Section IV, "Construction Storm Water BMP Performance Standards," and must prepare
a Storm Water Pollution Prevention Plan (SWPPP). If the answer to question I is "No," but the answer to any of the. remaining questions is "Yes," your project is subject to Section IV, "Construction Storm Water BMP Performance Standards," and must pr
e
p
a
r
e
a Water Pollution Control Plan (WPCP). If every question in Part C is answered "N
o
,
"
your project is exempt from any construction storm water BMP requirements.. if an
y
o
f
the answers to the questions in Part C are "Yes," complete the construction s
i
t
e
prioritization in Part D, below.
Part C: Determi -ie Coñstrüction .Phase Storm Water Requirements.
Would the project meet any of these criteria during construction? Yes No
Is the project subject to California's statewide General NPDES Permit 1o1 Storm Water Discharges Associated With ConstructiorrActMties?
Does the project propose grading or soil disturbance? Would storm water or urban runoff have the potential to contact any portion of the construction area, including washing and staging areas? Would the project use any construction materials that could negatively affect water
quality if discharged from the site (such as, paints, solvents, concrete, and
stãcco)?
31
TABLES FROM TUE STORM WATER STANDARDS MANUAL
I
I..
Storm Water Standards
4/03/03
When referred to this Section, by Step 2 of Section ii, complete the analysis required for
your project in the subsections'of Section fiLl below.
S
1. IDENTIFY POLLUTANTS & CONDITIONS OF CONCERN.
A. Identify Pollutants from the Project Area
Using Table 1, identify the project's anticipated pollutants. Pollutants associated with'
any hazardous materiel sites that have been remediated or are not, threatened by th
e
proposed project are not considered a pollutant of concern. Projects meeting t
h
d
definition of more than one project category shall identify all general pollutant categories that apply.'
•
Table 2. Anticipated and Potential PolTutants Gerrerted' by Land Use Type..
General Pollutant Categories
Project' Trash Oxygen' Bacteria
''l
Categories Heavy Organic & Demanding Oil & & Sediments t'iutrients Metals Compounds Debris Substances Grease Viruses Pesticides
X X X X X. X ' X
F
X X X P(') pt21 P(I) X
Commercial
S Developmen . Pill PC) PM . X P15) X PP) P(S) >100,000ft2 '
Automotive
.,
X X- X 4 X' Repair .
X XKX
*Res'10naurants
X X . . XX
' Pit) PC') X . • X PC') X' S
Streets,
Highways & x pcilx x ' X()
XLP(5)
x Freeways
Xariticipa(ed
S ' PpotntiaI
. A potential pollutant if landscaping exists on-site.'
' A po,tential pollutant if the project includes uncovered paiking areas.
A potential pollutant if land use involves food or animal waste products. , Including petroleum hydrocarbons.
• ' • 5 lncludin solvents. • S
12
p.: *
Storm Water Standards
4/03/03
Table 4. Structural Treatment Control BMP Selection Matrix.
Pollutant of Concern
- Treatment Control BMP Categories.
Biofilters . Detention Infiltration 1wetponds or Drainage Fi1ti-atioi Hydrodynamic Basins Basins(') Wetlands'. Inserts Separator Systems(2) Sediment M H I H H - I H . M Nutrients L I M M M L M I Heavy Metals M I M M H L . H I Organic Compounds U Ii U I U I L . M I L Trash &Debris I I H . U U I M f H I M Oxygen Demanding L. -
M M M L M I Substances
Bacteria U U H U L . I . M I Oil & Grease M M U U 1- 1 H I Pescides U . U U LI I I U I Including trenches and porous' pavement
. Also known as hydrodynamic devices and baffle- hoxe.
L Low removal efficiency . M: Medium removal efficiency
I-I: High removal efficiency
U. Unknown removal efficiency
Sources: Guidance Specifying Management Measures for Sources of Nonpoint Pollution in CoastafWateçs (1993), National Stonnwatr Rest Manaqethenl Practices Database (2001). and Guide for BMP Selection in Urban DevelopedAreas (2001).
Y. Restrictions on the Use of Infiltration Treatment BMPs
31. Treatment control BMPs that are designed to primarily function as infiltration
devices shall meet the following conditions (these conditions do not apply to treatment BMPs which allow incidental infiltration and are not designed to primarily function as infiltration devices, such as grassy swales, detention basins, vegetat
e
d
buffer sips, construGtod wetlands, etc.): (1J urban runoff from comnercial
developments shall undergo pretreatment to remove both physical and chemical.
contaminants, such as sedimentation or filtration, prior to infiltration; (2) all dry weather flows shall be diverted from infiltration devices except for those non-sto
r
m
water discharges authorized pursuant to 40 CFR 122.26(d)(2)(iv)(B)(1): diverted stream fiovs, rising ground waters, uncontaminated ground water infiltration [,s defined at 40 CFR 35.2005(20)] to storm water conveyance system
s
,
uncontaminated pumped ground water, foundation drains, springs, water from crawl space pumps, footing drains, air conditioning condensation, flow from riparian habitats and wetlands, waterline flushing, landscape'irrigation, discharges from potable water sources other than water main breaks, irrigation wafer,
individual residential car washing, and dechlorinated swimming pool discharge
s
;
pollution prvention and source control BMPs shall be implemented at a level
appropriate to protect groundwater quality at sites where infiltration structural
treatment BMPs are to be used; (4) the vertical distance from the base of any infiltration structural treatment BMP to the seasonal high groundwater mark shall be at least 10 feet. * Where groundwater does not support beneficial uses, this vertical distance criterion may be reduced, provided groundwater . quality is maintained; (5) the soil through which infiltration is to occur shall have physical and
21
FLOW BASED NUMERIC SIZING CALCULATIONS
The structural treatment BMPs for the La Costa Resort and Spa Master Plan Amendment project
will be sized using flow based criteria per the City's Storm Water Standards Manual, Table 3.
This criteria states that the "flow based BMPs shall be designed to mitigate (infiltrate, filter or
treat) the maximum flow rate of runoff produced from a rainfall intensity of 0.2 inch ofrairifail
per hour.' Structural BMP. sizing calculations areas follows:
Bio-Clean Filters
Per the manufacturers specifications (see calculations, this Appendix), one Bio-Clean filter is
capable of treating a runoff flow of 0.35 cfs based on the above described area. Therefore the maximum surface area that can be effectively treated by one Bio- Clean Filter is S acres, per the following calculations:
Q=CIA, therefore A=Q/CW; Q=0.85 cfs, 1=0.2 in/hr, and assuming a commercial runoff
coefficient, C, of 0.85
A-0.85/0:85 (0.2)=5.0 acres.
Per the attached site BMPIBasin Area Exhibit (see Map Pocket) the two existing inlets located at
node 620 (per the La Costa Resort and Spa Master Plan Drainage Study, dated November 3,
2003) collect runoff from the largest contributing area of 8.3 acres (this area is conservative in
that it includes some landscaped, area which will be picked up by the private underground storm
drain system). Per the calculation above, the Bio-Clean inserts to be installed in these two
existing inlets will be able to treat a combined maximum area of 10 acres and will therefore have
sufficient capacity to treat the runoff from this area. The contributing area to each of the
renaaining four Type B inlets (located at nodes 510, 540, 541 and 621 per the attached Site BMP/Basin Area Exhibit) is less than 5 acres. Therefore the Bio-Clean inserts to be installed in
these inlets wilt also have sufficient capacity to treat the surface runoff within each area.
CDS Technologies Storm Water Treatment Unit
Per the La Costa Resort and Spa Master Plan Drainage Study dated November 3, 2003, the total basin area contributing runoff, to be rated to the proposed CDS Unit (node 544) is approximately tentythree acres. The storm runoff required to be treated by this unit, per the Cityts Storm
Water Standards Manual, is calculated as follows:
Q—CIA, where C=0.85, 1=0.2 in/hr, A=23 acres
Q=(0.85) (0.2) (23) = 3.9 1, or approximately 4 cfs
The CDS Unit, Model No. PMSU40 30 is designed for a maximum flow of 4.5 cfs and is proposed to be used for this project.
PLAN VIEW
CDS MODEL PMSU4030,
4.5 CFS TREATMENT CAP
ELEVATION VIEW
.SEE - SHEET 2
STORM
PIPE ,—XX'Ø DUTLET PIPE
30'0 MM FRAME
AND COVER (TYPICAL) ALTERNATIVE ACCESS HATCH SYSTEM READILY
AVAILABLE
OPTII3NAL
mL BAFFLE
•. L1tftLJLL
moo acoaccloo
3120 17
L ' LL
LL LLLLELLL~Lkt~, LLLL _L
LLL
LL Q00130130 cloca
00,2000
.(
96' Th CDNC.
HH RISER
\_CNCRETE
TOP CAP
Lim INLET PIPE
1 ...
L:ELEVATION VIEW
SEE SHEET.2
I
_
TM
TECHNOLOGIES
TENTED
NOTE:
THE INTERNAL COMPONENTS ARE SHOWN IN THE RIGHT-HAND CONF1GURA11ON-THESE COMPONENTS MAY BE FURNISHED IN THE
MIRROR IMAGE TO THAT • SHOWN (LEFT-HAND CONFIGURATION).
DATE SCALE PROJECT/ DEVELOPMENT 3/24/00
. i NAME DRAWN SHEET
CITY k STATE
APPRQV,
. I
CENTER OF 96'0 -CENTER
RISER SECTIONS
CENTER OF SCREEN,
2870 SUMP OPENING
4.8ø SEPARATION SCREEN.
SEE NOTE NO. 2
ATTACH SCREEN TO SLAB USING 4 ANCHOR BOLTS,
SUPPLIED BY COS.
ACCESS RISER,
a•-•o" I.D.
. .. SECTION VIEW.
CBS MODEL PMSU40_30,
4.5, CFS TREATMENT CAP.
XX0 OUTLET PIPE
ROTO-HAMMER OR SAW CUT OPENINGS FOR PIPE INLET AND OUTLEF
AS NECESSARY
1L STDRM
PIPE
OIL BAFFLE
• fFft A LLLL
• / \j..LLLLLLL
LLLLLLLj
(1
\y H-
RTATE SEPARATION SLAB TOOBTMN .• INDICATED OFFSET ••. - . • S.. DISTANCES a
. .•
. 4.
FLANGES ON INLET SIDE S'& 8011DM ATTACHED TO RISER WALL USING 5: ANCHOR -BOLTS.-MINIMUM-(SUPPLIED
BY COS TECHNOLOGIES)
Xxi* INLET PIPE
I-.
. NOTES:
•..
THE INTERNAL COMPONENTS ARE SHOWN IN THE RIGHT-HAND
.
CONFIGURATION-THESE COMPONENTS MAY BE FURNISHED
I
N
T
H
E
MIRROR IMAGE TO THAT ..SHOWN (LEFT-HAND CONFIGURATION).
FOR PROPER INSTALLATION, GREEN FLANGE ON SCREEN FACES . UP.
I . DATE I SCALE PROJECT/ DEVELOPMENT 3/24/00 i "=2.5' TM NAME DRAVN C7DS /
SHEET I
••.
CITY & STATE APPRDV • • . • . • . :3 TCHES
• PATENTED..
. .:. . . . .......
I...
__
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&O C.E.N ST04MWATEK SYSTE1S
P Box 869, Oceansida, CA 92049-
Phone (760) 433-7640 Fax (760) 433-3176
I
(•.::. . TecIthdogie I -. . .
1
I •• an Diego regional standard Curb InIft- Type
Fm M-4 Manhole
19 AIX
Catches of
Floatables om$ I I •
ME catcher . .. overffow sides and front , 4,
[i • . • ___
_________
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lr. 12.
iiab1 j
.4 • basket
catches.
r out!
12" verything
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Remove mate
Curb I mánhôle
f I. •t without i inlet, I • entry. Ii• baskëlJ
-. ___________ - . . • ______ • . •. - • .
PATENT PENDING
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R'sc rtnr 'sw tj
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fo. c.-L..gk' Co 9-3
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I
NT Ti CA c gAT r L we I iF S
HANDBOOK OF HYDRAULICS
.
WEIRS
.
Table 5-3. Values of C in the Formula Q CLH for Broed-
Table 5..5. Values of C In the Formula Q CLHS for Broad,.
crested Weirs
-
crested Weirs with Crests Inclined
S
l
i
g
h
t
l
y
D
o
w
w
a
r
d
Dreadth Measured of crest Of wzly In fe't
t.00 L.
.01
Crest Energrhead - R, 0.2 72.t'.752.592.62 2.54 s,4? 42.38 2.94
2
.
4
0
2
.
8
0.4 I 2.922.8o2.722.642.6124l2.
5
8
t
.
5
4
2
,
3
0
2
.
5
6
2
.
1
0.13 \_ s.srz.1a2.642,6t2.642.6*.602.70 2.70 2.7 3,8O3.042.832.682.602.6002 2.88 3.59 2.134 .823.t42.9S2.752.62,642.652.672
.
5
8
2
.
6
8
2
.
6
2
1.6
1.2 3.323.203;082.862.702.652.642.6
7
.
1
3
8
2
.
6
0
2.64 0..55 9.57 2.54
0.5 0.6 0.7 0.8 0.9° 1.0 1.2 1.4 1.5 Level ................... 2.79 2,80 2.81 2.82 2.83 2.55 2.85 2.95
.2.75 Slope 0.004 ........... 2.15 2.94 2.93 2.93 2,012.90 2.88 2.87 2,87
Slope 0.928 ...........S.°73.053.053,043ô33033.00 2.09 I
I 1 1.4
i IS 3 82 3.!1260 3-28 3.07 2.80 2.65 2.54 2,6
- . (II)
LB 332 3.32 3.31 ä.07 2.88 2.74 2.qg 2.66
2
.
6
3
2.64 2.6
2.0 3.32 3L31 a.ao 8.03 2.85 2.75 2.72 2.68 2.55 2.64 2.6
slop of
Head In feet, Y
-.
. 60 3823 923 323 3232O3052O2
2
3
2
6
6
2
6
4
2
.63
0tl02o304l051o6o
7
oreet
Irk feet
orweir
12 to~ i i Ni :
5,6 3,323.823.323.322.323.323,323.322
.
8
8
2.5 4.26
'
Table 5-4 Values of C in rormula Q CIP' for Models Table 5 Values of
LRf or Weirs of Section with Vertical. -Upstrearn Face
of Broatl-crestd Weira with Foun
e
d
tIstrehl Corner
and Sloping Downstream Face
r : 1\0\4
N~Me of
-.00\ 0.9 1.0
'. Iro.oIi.oji.s
J
i
•
;
.
I I
•
. .
' : : ::::: :3.08 : 3.313.50 ::2.62
:: \:S.::Deep e
0.33
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-
-
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