HomeMy WebLinkAboutCT 03-01-03; LA COSTA RESORT & SPA PHASE 3; STORM WATER MGMT PLAN; 2007-04-30HUNSAKER
&ASSOCIATES
E C O,
PLANNING
ENGINEERING
SURVEYING
IRVINE
LOS ANGELES
RIVERSIDE
SAN DIEGO
ARIZONA
STORM WATER
MANAGEMENT PLAN
for
LA COSTA RESORT &
SPA PHASE III
CT 03-01
City of CarlsbacJ, California
Prepared for:
Cameo Homes
1107 Quail Street
Newport Beach, CA 92660
LAJI
iiiwf,™iiJI
w.o. 2534-3
April 30, 2007
Hunsaker & Associates
San Diego, Inc.
DAVE HAMMAR
LEX WILLIMAN
ALISA VIALPANDO
DAN SMITH
RAY MARTIN "
CHUCK CATER RaY^x6hdi L. Martin, R.C.E.
Vice Tresident
9707 Waples Street
San Diego, CA 92121
(858) 558-4500 PH
(858) 558-1414 FX
www.Hunsai<erSD.com
lnfo@HunsakerSD.com
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w.o. 2534-3 5/4/2007 9:03 AM
La Costa Resort & Spa Phase llll
Storm Water Management Plan
TABLE OF CONTENTS
CHAPTER 1 - Executive Summary
1.1 Introduction
1.2 Summary of Proposed Development
1.3 Results and Recommendations
1.4 Conclusion
1.5 References
CHAPTER 2 - Storm Water Criteria
2.1 Regional Water Quality Control Board Criteria
2.2 City of Carlsbad SUSMP Criteria
CHAPTER 3 - Treatment Control BMP Design
3.1 BMP Location
3.2 Determination of Treatment Flow
3.3 BMP Unit Sizing
3.4 CDS Treatment Units
CHAPTER 4 - Source Control BIVIPs
4.1 Landscaping
4.2 Urban Housekeeping
4.3 Automobile Use
4.4 Integrated Pest Management Principles
4.5 Storm Water Conveyance Systems Stenciling and Signage
4.6 Efficient Irrigation Practices
4.7 Pet Ownership Responsibility
CHAPTER 5 - Site Design BMPs
5.1 Site Design BMPs
5.2 Minimize Impervious Footprint
5.3 Conserve Natural Areas
5.4 Permeable Pavements
5.5 Minimize Directly Connected Impervious Areas
5.7 Maximize Canopy Interception & Water Conservation
5.8 Residential Driveways & Guest Parking
5.9 Trash Storage Areas
CHAPTER 6 - Fiscal Resources
6.1 Agreements (Mechanisms to Assure Maintenance)
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List of Tables and Figures
Chapter 1 - Watershed Map
Chapter 2 - Stomn Water Requirements Applicability Checklist
Chapter 2 - Site Design and Source Control Storm Water BMP Selection Matrix
Chapter 3 - BMP Location Map
Attachments
BMP Location Map
"Stom? Water Management Plan for La Costa Resort & Spa - Master Plan
Amendment", Rick Engineering Company; October 2003.
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CHAPTER 1 - EXECUTIVE SUMMARY
1.1 - Introduction
The La Costa Resort & Spa Phase III site is located north ofthe intersection of El
Camino Real and Costa Del Mar Road in the City of Carisbad, California (see
Vicinity Map on this page). The 2.5-acre site is located within the greater La Costa
Resort and Spa development.
CITY OF OCEANSlOE
Hicmi»T . —
CITY OF ENONITAS
r
PRCJECT
LOCATION
VICINITY MAP
NOT TO SCALE
All runoff from the project site will drain south to the existing 36-inch RCP storm
drain within El Camino Real, ultimately draining to San Marcos Creek. Runoff from
San Marcos Creek eventually discharges into Batiquitos Lagoon.
Per the City of Carlsbad SUSMP, the La Costa Resort & Spa Phase III project is
classified as a Priority Project and subject to the City's Permanent Storm Water BMP
Requirements.
Treatment of storm water runoff from the overall La Costa Villas project site has
been previously addressed in a separate, approved SWMP document-the "Stom?
Water Management Plan for La Costa Resort - Master Plan Amendment' dated
October 2003 by Rick Engineering Company.
This Storm Water Management Plan (SWMP) has been prepared pursuant to
requirements set forth in the City of Carlsbad's "Standard Urban Storm Water
Mitigation Plan (SUSMP)." All calculations are consistentwith criteria setforth by
the Regional Water Quality Control Board's Order No. 2001-01, and the City of
Carlsbad SUSMP.
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This SWMP recommends the location and implementation of site and source control
BMPs.
The approved Rick Engineering Master SWMP has been attached to this site
specific Phase III SWMP document to provide information in regards to expected
pollutants of concern, conditions of concern, flow-based BMPs and the operation
and maintenance of such infrastructure forthe master La Costa Resort and Spa
development.
1.2 - Summarv of Developed Conditions
The La Costa Resort & Spa, Phase 3 project proposes construction of resort villas,
commercial buildings, and a parking structure.
It must be noted that hydrologic impacts for the overall development of La Costa
Resort & Spa have been addressed in a separate report named "Drainage Study for
La Costa Resort & Spa" dated September 2006 by Hunsaker and Associates.
Runoff from the developed site is collected and conveyed southerly via one (1) storm
drain system within the project site, draining to a 24-inch storm drain. This 24-inch
storm drain conveys flow in a southerly direction to a 36-inch storm drain adjacent to
El Camino Real. These flows then ultimately discharge to San Marcos Creek.
A runoff coefficient of 0.82 was assumed for the proposed developed site as per the
"2003 San Diego County Hydrology Manual". Per the "Drainage Study for La Costa
Resort & Spa Phase III", dated January 2007 by Hunsaker & Associates, peak flow
data from the developed site is summarized in Table 1 below.
TABLE 1 - Summary of Developed Conditions Peak Flows
Drainage Area (Ac) 100 Year Peak
Discharge (cfs)
Ultimate Developed
Condition 2.5 8.1
Per Master Drainage
Study 2.5 8.1
Difference 0 0
Priorto exiting the existing 36-inch storm drain, runoff from Phase
Resort and Spa development is treated via a CDS unit.
of the La Costa
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This CDS unit was sized previously perthe approved "Storm Water Management
Plan for La Costa Resort - Master Plan Amendment' dated October 2003 by Rick
Engineering Company. However, this master CDS unit sizing was updated per the
approved "Drainage Study for La Costa Resort & Spa" dated September 2006 by
Hunsaker & Associates.
The Regional Water Quality Control Board has identified San Marcos Creek as part
ofthe Carlsbad Hydrologic Unit, San Marcos Hydrologic Area, and the Batiquitos
Hydrologic Subarea (basin number 904.51).
1.4- Results and Recommendations
Per the approved "Storm Water Management Plan for La Costa Resort - Master
Plan Amendment' dated October 2003 by Rick Engineering Company, a single flow-
based BMP is provided to treat 85**^ percentile runoff from the site priorto discharge
from the La Costa Resort & Spa project site.
Table 2 below summarizes rational method 85**^ percentile calculations forthe
proposed water quality discharge generated via the La Costa Resort & Spa Phase 11
portion of the overall La Costa Resort & Spa development.
Table 2 - Developed Conditions 85**^ Percentile Calculations for Phase III
Tributary
Drainage
Area
(acres)
Rainfall
Intensity
(inches/hour)
Runoff
Coefficient
85'" Pct.
Design Flow
(cfs)
Phase III 2.5 0.2 0.82 0.4
Table 3 - Developed Conditions 85*^ Percentile Calculations for the
Master La Costa Resort & Spa
Treatment
Unit
Drainage
Area
(acres)
Rainfall
Intensity
(inches/hour)
Runoff
Coefficient
85'" Pct.
Design Flow
(cfs)
CDS 28.9* 0.2 0.82 4.7
*=inclusive of offsite tributary areas
Rational Method calculations predicted an 85*^ percentile runoff flow of
approximately4.7 cfs (ofwhich the Phase III generates approximately 0.4 cfs) for
the area discharging to the existing master CDS treatment unit.
Per the approved DWG# 422-6D "Storm Drain Profile for La Costa Resort & Spa -
Costa Del Mar Entry" by RBF Consulting, dated September 2006, a CDS
PSWC40_40 offline treatment unit has been constructed to treat flows generated via
the Master La Costa Resort & Spa development.
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CARLSBAD
WATERSHED MAP FOH
LA COSTA RESORT
& SPA PHASE 3
CITY OF CAHLSBAD, CAUFORNH
•3 \\\\ i\« ' \ il CITY OF CARLSBAD, CALIFQHNIA
lli\DeiSM,Kyd\US<H09-WIF-SlTCHAFjlag[ eOB51Jan-24-E007il&aa
Permeable pavements were also evaluated for implementation within the La Costa
Resort & Spa Phase 111 project site. However, due to several factors including
porous pavements high failure rate, porous pavements have been deemed
infeasible for the La Costa Resort & Spa Phase 111 project site. A full discussion is
provided within Chapter 7 of this report.
The approved Rick Engineering Master SWMP has been attached to this site
specific Phase 111 SWMP document to provide information in regards to expected
pollutants of concern, conditions of concern, flow-based BMPs and the operation
and maintenance of such infrastructure for the master La Costa Resort and Spa
development.
1.5 - Conclusion
The combination of proposed construction and permanent BMP's will reduce, to the
maximum extent practicable, the expected project pollutants and will not adversely
impact the beneficial uses ofthe receiving waters.
1.6- References
"Standard Urban Storm Water Mitigation Plan - Storm Water Standards", City of
Carlsbad, April 2003.
"Standards for Design and Construction of Public Works Improvements in the City of
Carlsbad", City of Carlsbad, California; April 1993.
"Master Drainage and Storm Water Quality Management Plan", City of Carlsbad,
California; March 1994.
"Drainage Study for La Costa Resort & Spa Phase III", Hunsaker & Associates,
January 2007.
"Hydrology Manual", County of San Diego Department of Public Works - Flood
Control Division; Updated April 1993.
"San Diego County Hydrology Manual", County of San Diego Department of Public
Works - Flood Control Section; June 2003.
"Order No. 2001-01, NPDES No. CAS0108758 - Waste Discharge Requirements for
Discharges of Urban Runoff from the Municipal Separate Storm Sewer Systems
(MS4s) Draining the Watersheds ofthe County of San Diego, the Incorporated Cities
of San Diego County, and San Diego Unified Port District", California Regional
Water Quality Control Board - San Diego Region; February 21, 2001.
"Water Quality Plan forthe San Diego Basin", California Regional Water Quality
Control Board - San Diego Region, September 8, 1994.
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CHAPTER 2 - STORM WATER CRITERIA
2.1 - Regional Water Qualitv Control Board Criteria
All runoff conveyed in the proposed storm drain systems will be treated in
compliance with Regional Water Quality Control Board regulations and NPDES
criteria prior to discharging to natural watercourses. California Regional Water
Quality Control Board Order No. 2001-01, dated February 21, 2001, sets waste
discharge requirements for discharges of urban runoff from municipal storm
separate drainage systems draining the watersheds of San Diego County.
Perthe RWQCB Order, post-development mnoff from a site shall not contain
pollutant loads which cause or contribute to an exceedance of receiving water
quality objectives or which have not been reduced to the maximum extent
practicable. Post-construction Best Management Practices (BMPs), which refer to
specific stomn water management techniques that are applied to manage
construction and post-construction site runoff and minimize erosion, include source
control - aimed at reducing the amount of sediment and other pollutants - and
treatment controls that keep soil and other pollutants onsite once they have been
loosened by storm water erosion.
Post construction pollutants are a result ofthe urban development ofthe property
and the effects of automobile use. Runoff from paved surfaces can contain both
sediment (in the form of silt and sand) as well as a variety of pollutants transported
by the sediment such as trash & debris, oil & grease, heavy metals and organic
compounds. Landscape activities are an additional source of sediment.
All structural BMPs shall be located to infiltrate, filter, or treat the required runoff
volume or flow (based on the 85*^ percentile rainfall) prior to its discharge to any
receiving watercourse supporting beneficial uses.
2.2 - Citv of Carlsbad SUSMP Criteria
Per the City of Carlsbad SUSMP, the La Costa Resort & Spa Phase III project is
classified as a Priority Project and subject to the City's Permanent Storm Water BMP
Requirements. These requirements required the preparation ofthis StormWater
Management Plan.
The Storm Water Applicability Checklist, which must be included along with Grading
Plan applications, is included on the following page.
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•AFFHNDIXA
STQRM WATER REQUIREMENTS APFUCAaiLTTY CHECKUST
Ssction 1. Pennanant Storm Water BMP Raquiraments: '
pqemisiiy exposed to ur&an ninaiT • ~ ' ^' ^^S'^'n!?®'^' highways, and Trss-tfaya which vrauld areata a new pavsd suracs thsi is ^•POQ sauare fast or graater g. uuu square fest or graater ^
pS^[St?anriS"'^°"' ggctionin the Stonn W^rStandafds farexpandgd dennitjanscf the priority
LimitsiJ I
priQrit^/'DmteS oIS"*,'^ T'iif "'^°5^r'^-ff!^''^=^ "^'^ Prajs'^ sre not considered EriSrih^ ^"'•'^''Ss and atherstnjdurss associated >wiih utiltty praieds ara
30
•3
i
1
Watar standards
Pgli5LDgt3n:,insstandard -^^ ^ .
Does tha prciect pran«?sa: I ~—I
T23 I Na
1 a nna out iryourproject is required to obtain an individual General MPnpq D=^-* - o.—krr
toarges Assodated v/ith IndLstrial Activities, visit ttia .^SR^^^^ • lat Ww.swreh gav/starmwtriindustrial.htrnl '"^ ^^^^"^ Rasources Contral Board web site
Section 2. Construction Storm Water BMP Requiraments-
f
'4
31
4103/03 • ^^'^^^'•uS
^LSffSce wt^ the Municipal Pe^t eaS^n.tn,..
cSdnrLI "njlwonon priority dOM affect the frS^n^^^'^*?®^ °" a rase-by..cSsa
ET''^; HighPn'oiity
1) PrQjects whara the sfte is 50 acres or mora and n«HTn •„
rainy season grading will occur during the
2) Projects 5 acres or mare. 3) Proiects *5
adjacent to or discharging (iiractly to a coaS^^ °' ^'^^^^V
. WKhin an environrnenially sensitive area ^ ""^"^'^"S ^^^sr
Projects, active or lnaciive, acflacent ortrifauta^ to sen.rave water bodies
Q B) Medium Priority
1) Capital improvemsnt Projects whera orawsnn r,^^.,
Polliition Pravention Plai^ (SvS il^oi r ^T^^-'" ^ ^atar
Construcfion Permit (La wSer aSsswS S, underthe State General
^^^^aetre^iignmefereninrc^^^^^^
^) Perrnri projects in tha public rightnaf-wav wherp nr^w-
.nstallation of-sidewalk, substar^al SnfwSs^^o^S^ "f"^^ '"-'^
en.re s^eet frontage, etc.. however SV^^^^^ 9-^-
3) Permit projects on private p.rQperfy where aradinr, n ^
fiowever, Notica Of Intents (NOIs) and Si/PPpfaJrL'I'JiL'''
• • c; Law Priority
•1) Capital Projects where minimal to no gradinq occur, ^HOH . • n- ^. .
IQOP Installations, street light installations,
2) Permit projects In the public right-ofrway where minimal rn n« ^-
' STn* r Sirs ^'r,^"?'^? - «
• impw/emert3 ak ^ ^ ' ''"Sl^'^Hy homes, small tanani
32
Chapter 3 - TREATMENT CONTROL BMP DESIGN
3.1 - BMP Location
Perthe approved "Storm Water Management Plan for La Costa Resort - Master
Plan Amendment' dated October 2003 by Rick Engineering Company, a single flow-
based BMP is provided to treat 85'^ percentile runoff from the site priorto discharge
from the La Costa Resort & Spa project site.
A CDS flow based treatment unit is located at the southwestern corner of the project
site adjacent to El Camino Real.
The enclosed map shows the location ofthe proposed flow-based BMPs.
3.2 - Determination of Treatment Flow
Flow-based BMPs shall l3e designed to mitigate the maximum flowrate of runoff
produced from a rainfall intensity of 0.2 inch per hour. Such BMP's utilize either
mechanical devices (such as vaults that produce vortex effects) or non-mechanical
devices (based on weir hydraulics and specially designed filters) to promote settling
and removal of pollutants from the runoff.
Per the request of the City of Carlsbad, 85*^ percentile flow calculations were
performed using the Rational Method. The basic Rational Method mnoff procedure
is as follows:
Design flow (Q) = C * 1 * A
Runoff Coefficient (C) - The weighted runoff coefficient for the treatment unit was
determined using the areas analyzed in the final engineering hydrology report. The
runoff coefficient is based on the following characteristics ofthe watershed:
Land Use - Commercial/Resort
- Soil Type - Hydrologic soil group D was assumed for all areas. Group D
soils have very slow infiltration rates when thoroughly wetted. Consisting
chiefly of clay soils with a high swelling potential, soils with a high
permanent water table, soils with clay pan or clay layer at or near the
surface, and shallow soils over nearly impervious materials. Group D soils
have a very slow rate of water transmission.
Rainfall Intensity (I) - Regional Water Quality Control Board regulations and NPDES
criteria have established that flow-based BMPs shall be designed to mitigate a
rainfall intensity of 0.2 inch per hour.
Watershed Area (A) - Corresponds to total area draining to treatment unit.
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I 11
I I
HUNSAKER & ASSOCIATES LA COSTA RESORT & SPA
(INCLUSION OF PLANNING AREA III)
CITY OF CARLSBAD, CAUFORNIA
SHEET
1
OF
1
R<\D61S\LH).d\elS«H09-IHP-SlTE:H/tP.d>B[ eDB3iten-e4-2in7ii(e;;
The 85"^ percentile flow rate has been calculated using the Rational Method.
Required data for the Rational Method Treatment flow determination is as follows:
Table 4 - Developed Conditions 85"^ Percentile Caiculations for Phase III
Tributary
Drainage
Area
(acres)
Rainfall
Intensity
(inches/hour)
Runoff
Coefficient
SS'*^ Pct.
Design Flow
(cfs)
Phase III 2.5 0.2 0.82 0.4
Table 5 - Developed Conditions 85"^ Percentile Calculations forthe
Master La Costa Resort & Spa
Treatment
Unit
Drainage
Area
(acres)
Rainfall
Intensity
(inches/hour)
Runoff
Coefficient
85'" Pct.
Design Flow
(cfs)
CDS 28.9* 0.2 0.82 4.7
'=lnclusive of offsite tributary areas
Rational Method calculations predicted an 85*^ percentile runoff flow of
approximately 4.7 cfs (ofwhich the Phase 111 generates approximately 0.4 cfs) for
the area discharging to the existing master CDS treatment unit.
Perthe approved DWG# 422-6D "Storm Drain Profile for La Costa Resort & Spa -
Costa Del Mar Entry" by RBF Consulting, dated September 2006, a CDS
PSWC40_40 offline treatment unit has been constructed to treat flows generated via
the Master La Costa Resort & Spa development.
3.3-BMP Unit Sizinq
3.3.1 CDS Unit Sizing
Calculations show that a CDS PSWC40_40 provide sufficient treatment capacity to
treat the design 85'^ percentile flow. These units are an inline system and do not
require the construction of a special diversion box upstream ofthe treatment unit.
The following table shows the treatment capacities ofthe proposed CDS unit.
CDS UNIT TREATMENT CAPACITY TABLE
Treatment Unit
85''' Pct.
Design Flow
(cfs)
CDS Model Treatment Capacity
(cfs)
Master CDS Unit 4.7 PMSU 20-20 6
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3.4 - CDS Treatment Units
The Continuous Deflective Separation (CDS) storm water pollution control devices
are designed for the sustainable removal and retention of suspended solids and
floatables from storm water. CDS technology utilizes a non-blocking, non-screening
process to remove pollutants from storm water flow.
According to CDS information, these units capture fine sands and solids and are
capable of removing more than 80 percent of annual total suspended solids from
storm water. Additionally, CDS units are reported to remove 100 percent of
floatables as well the following:
100% of all particles in the storm water equal to or greater than one-half the size
of the screen opening
93% of all particles equal to or greater than one-third the size ofthe
screen opening
53% of ail particles equal to or greater than one-fifth the size of the
screen opening
Standard CDS units have no moving parts (they are gravity-driven bythe hydraulic
energy in the storm waterflow)), require no power or supporting infrastructure, and
according to CDS information will not clog. Screen and supporting hardware are
made of stainless steel and designed to resist corrosion. The units are installed
below ground.
CDS units have large sump capacities relative to their design flows and only need to
be cleaned out with a standard vactor truck one to four times per year. This
operation eliminates workers' exposure to materials captured in the units.
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LA COSTA RESORT AND SPA
COSTA DEL MAR ENTRY, SD UNE L-1
CARLSBAD, CA
AUGUST 17, 2006
CDS Model PSWC40 40
Qtreat 6 cfs
Q system 82.18 cfs Total Flow in Slorm Drain
Hcds 1 ft Required Head Difference to Process Q treat
D/S Pipe Size 3.0 ft
D/S Pipe Slope 0.0101 ft/fl
U/S Pipe Size 3.0 ft
U/S Pipe Slope 0.0394 ft/R
"i • • " r ^WEIR HElGHTaCi
-Y.^s
Y d/s Case 1 0.76 fl Crilical Depth in CDS Outlet
Yd/3 Case2A 0.85 ft Crilical Deplh in d/s Pipe + Hcont (supercritical flows)
Y d/s Case 28 N/A ft Normal Depth in d/s Pipe + Hcont {subcritical flows)
Y d/s Case 3 N/A ft Yd/s from Receiving Water Level
Controlling Y d/s 0.85 ft
Calculated Weir Heigtit 1.85 ft Controlling Y d/s + H ods
Use Welr Heiqht r-11"
3SM^S5S'i?iSMfl^^SAM^ WEIR BOX AJiSYSTEIV! FLOW • ^:'4:--.^-; --; v-.i.;v
SDStationD/SofCDS X+XX
1 Pipe Invert El d/s of CDS 12.17
2 Rnlshad Grade El @ CDS 19.00
3 EGL El d/s of Welr Box 18.29 3 HGL El d/s of Weir Box 16.19 From Plans
Weir Box Height 5 ft
Weir Box Width 7 ft
4 Hcont 0.94 ft Contraction Loss from Welr Box to d/s Pipe
5 EGL El d/s of Weir 19.22 5 HGL El d/s of Weir 19.14
6 Hweir 0.60 ft Loss Created by Fiow Through Orifice Over Weir
7 EGL El u/s of Welr 19.82 7 HGL El u/3 of Weir 19.74
8 Hexp 1.23 ft Expansion Loss from u/s Pipe to Weir Box
9 EGL u/s of Weir Box 21.05 9 HGL El u/s of Welr Box 18.95
SD Station U/S of CDS x+xx
Increase in HGL 2.78 ft
FreelwardU/SofCDSUnit 0.05 ft
Length to 1ST U/S Manhole/CB 37.81 ft
Rim Bevation at 1ST U/S Manhole/CB 20.5
Friction Loss lo 1ST U/S Manhole/CB 0.57 ft
HGL El at 18T U/S Manhole/CB 19.53
Freeboard at 1ST U/S Manhole/CB 0.97 ft NO FLOODING OCCURS AT 1ST U/S MANHOLE/CB
Loss of Head Due to Contractions
For Higher Velocities with H > 1.0 foot;
For Lower Velodties wilh H < 1.0 foot:
Lo33 of Head Due to Welr
For Welr (free discharge):
For Submerged Welr
For WeirfOrifice (pressure):
Loss of Head Due to Expansion/Enlargement;
For All Situations:
Hcont= (1/0-1)^ *Iv'/2g] c= 0.582 + 0.0418/(1.1 -r)
r = ratio of pipe diameters
Hcont = 0.7*(v1-v2)'/2g
Hweir = [Q/cLr c=3.08
Hweir = Hu/s-Hd/s
Hu/s = [Q/Ks*cLf° c = 3.08
K3 = [1-(Hd/s/Hu/s)'Y"*
Hweir = [Q/cAorf/2g c=0.6
Hexp = 1.098 Kvl - v2)'-'"] / 2g
o o w
tH txi >
C/D t-^ ^ td Q > g o
« > ^
ro
o S -n q
i
o
(D HGL/EGL u/s
of Weir Box
Q m
-(2) FINISHED GRADE EL
0 HGL/EGL u/s of Weir
HGL/EGL d/s of Weir
HGL/EGL d/s
of Weir Box
® D/S INV EL
OFF-LINE CDS UNIT WEIR BOX
TOTAL HEAD LOSSES
CHAPTER 4 - SOURCE CONTROL
4.1 - Landscapinq
Manufactured slopes shall be landscaped with suitable ground cover or installed with
an erosion control system. Landowners will be educated as to the proper routine
maintenance to landscaped areas including trimming, pruning, weeding, mowing,
replacement or substitution of vegetation in ornamental and required landscapes.
Per the RWQCB Order, the following landscaping activities are deemed unlawful
and are thus prohibited:
Discharges of sediment
- Discharges of pet waste
Discharges of vegetative clippings
- Discharges of other landscaping or construction-related wastes.
During landscaping operations both during and after construction, landscape
maintenance should be completed proactively. When these operations are in
progress, bare or disturbed areas should be re-seeded/re-vegetated as quickly as
possible to ensure that erosion is minimized. In addition, when landscape
maintenance operations require the stockpiling of materials for longer than a period
of one day, these stockpiles should be covered to minimize the opportunity for
rainfall to come in contact with the material.
4.2 - Urban Housekeeping
Fertilizer applied by homeowners, in addition to organic matter such as leaves and
lawn clippings, all result in nutrients in storm water runoff. Consumer use of
excessive herbicide or pesticide contributes toxic chemicals to mnoff. Landscaping
staff will be educated as to the proper application of fertilizers and herbicides to
lawns and gardens.
The average landscaped site contains a wide variety of toxins such as oil/grease,
antifreeze, paint, household cleaners and solvents. Landscaping staff will be
educated as to the proper use, storage, and disposal of these potential storm water
runoff contaminants.
Perthe RWQCB Order, the following housekeeping activities are deemed unlawful
and are thus prohibited:
Discharges of wash water from the cleaning or hosing of impervious surfaces
including parking lots, streets, sidewalks, driveways, patios, plazas, and
outdoor eating and drinking areas (landscape irrigation and lawn watering, as
well as non-commercial washing of vehicles in residential zones, is exempt
from this restriction)
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- Discharges of pool or fountain water containing chloride, biocides, or other
chemicals
- Discharges or runoff from material storage areas containing chemicals,
fuels, grease, oil, or other hazardous materials
Discharges of food-related wastes (grease, food processing, trash bin
wash water, etc.).
4.3 - Automobile Use
Urban pollutants resulting from automobile use include oil, grease, antifreeze,
hydraulic fluids, copper from brakes, and various fuels. Homeowners will be
educated as to the proper use, storage, and disposal of these potential storm water
contaminants.
Per the RWQCB Order, the following automobile use activities are deemed unlawful
and are thus prohibited:
- Discharges of wash water from the hosing or cleaning of gas stations,
auto repair garages, or other types of automotive service facilities.
- Discharges resulting from the cleaning, repair, or maintenance of any type
of equipment, machinery, or facility including motor vehicles, cement-
related equipment, port-a-potty servicing, etc.
- Discharges of wash water from mobile operations such as mobile
automobile washing, steam cleaning, power washing, and carpet cleaning.
The Homeowners Association will make all homeowners aware ofthe
aforementioned RWQCB regulations through a homeowners' education program
(note: examples are from the City of Carlsbad). Homeowners should be notified via
HOA newsletter prior to the rainy season (Oct. 1^') of storm water requirements.
4.4 - Integrated Pest Management (IPM) Principles
Integrated pest management (IPM) is an ecosystem-based pollution prevention
strategy that focuses on long-term prevention of pests or their damage through a
combination of techniques such as biological control, habitation manipulation,
modification of cultural practices, and use of resistant plant varieties. Pesticides are
used only after monitoring indicates they are needed according to established
guidelines. Pest control materials are selected and applied in a manner that
minimizes risks to human health, beneficial and non-target organisms, and the
environment. More information may be obtained at the UC Davis website
(http://www.ipn.ucdavis.edU/WATER/U/index.html).
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IPM is achieved via the following:
Common Areas:
- Eliminate and/or reduce the need for pesticide use in the project design by:
(1) Plant pest resistant or well-adapted plant varieties such as native plants.
(2) Discouraging pests by modifying the site and landscape design.
Home Owners:
Educate homeowners on applicable pest resistant plants and native species
and also encouraging onsite landscaping design.
Pollution prevention is the primary "first line of defense" because pollutants
that are never used do not have to be controlled or treated (methods which
are inherently less efficient).
- Distribute IPM educational materials to future site residents/tenants.
Minimally, educational materials must address the following topics:
(1) Keeping pests out of buildings and landscaping using barriers, screens
and caulking.
(2) Physical pest elimination techniques, such as, weeding, squashing,
trapping, washing, or pruning out pests.
(3) Relying on natural enemies to eat pests.
(4) Proper use of pesticides as a last line of defense.
4.5 - Storm Water Convevance Svstems Stenciling and Signage
The proposed development will incorporate concrete stamping, or equivalent, of all
storm water conveyance system inlets and catch basins within the project area with
prohibitive language (e.g., "No Dumping - I Live in «name receiving water»"),
satisfactory to the City Engineer. Stamping may also be required in Spanish.
4.6 - Efficient Irrigation Practices
All maintained landscaped areas will include rain shutoff devices to prevent irrigation
during and after precipitation. Flow reducers and shutoff valves triggered by
pressure drop will be used to control water loss from broken sprinkler heads or lines.
4.7 - Pet Ownership Responsibilitv
Not applicable to this site because this site contains a resort where pets are not
typically allowed.
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Chapter 5 - SITE DESIGN BMPS
5.1 - Site Desiqn BMPs
Priority projects, such as the La Costa Resort & Spa Phase 111 development, shall be
designed to minimize, to the maximum extent practicable the introduction of
pollutants and conditions of concern that may result in significant impact, generated
from site runoff to the storm water conveyance system. Site design components can
significantly reduce the impact of a project on the environment.
5.2 - Minimize Impervious Footprint
Methods of accomplishing this goal include:
- Construct streets, sidewalks, and parking lots to the minimum widths
necessary to be in accordance with standards set forth by the City of
Carlsbad.
5.3 - Conserve Natural Areas
There is no current natural area to preserve onsite, hence this is not applicable.
5.4 - Permeable Pavements
Site design BMP alternatives such as pervious pavements were also considered for
use within the La Costa Resort & Spa Phase III project site. However, the use of
pervious pavements has several disadvantages such as:
Porous pavement has a tendency to become clogged if improperly
installed or maintained.
Porous pavement has a high rate of failure.
Anaerobic conditions may develop in underlying soils ifthe soil is
unable to dry out between storm events. This may impede
microbiological decomposition.
Expansive soils were found on-site
These factors listed influenced the decision to not include pervious pavements within
the site design.
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5.5 - Minimize Directiv Connected Impervious Areas
Methods of accomplishing this goal include:
Draining rooftops into adjacent landscaping prior to discharging to
the storm drain.
Draining roads, sidewalks and impervious trails into adjacent
landscaping.
These site design techniques will not be implemented within the La Costa Resort &
Spa Phase III project. Roof drains will not discharge to receiving swales as the
swales would be located directly adjacent to the building walls, leading to possible
undermining of the buildings' structural foundations.
In orderto prevent possible damage to the proposed development, all lots will be
serviced by individual area drains, discharging flow to the receiving storm drain
system.
5.6 - Residential Drivewavs & Guest Parking
As this is a multi-family residential development and not a single family residential
development, no driveways have been proposed for the project site. Residences
are serviced by a surface parking lot.
As such, no site design has been specified for this purpose.
5.7 - Maximize Canopv Interception & Water Conservation
Landscaping on site will incorporate the planting of native, drought tolerant
vegetation to meet this requirement.
5.8 - Trash Storage Areas
Trash storage areas could be sources of bacteria pollutants. As such, all outdoor
trash container areas shall meet the following requirements. A "trash containment
area" refers to an area where a trash receptacle or receptacles are located for use
as a repository for solid wastes. Design for such areas will include:
- Paved with an impervious surface, designed not to allow run-on from
adjoining areas, screened or walled to prevent off-site transport of trash.
- Provide attached lids on all trash containers that exclude rain, roof or
awning to minimize direct precipitation.
Note: All trash container areas will be located indoors, thus will not come in contact
with storm water.
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Chapter 6 - FISCAL RESOURCES
6.1 - Agreements (Mechanisms to Assure Maintenance)
There are multiple flow-based BMP treatment units within the La Costa Resort &
Spa development for storm water quality treatment.
Funding forthe water quality treatment devices will be provided by the Master La
Costa Resort & Spa HOA. The Master La Costa Resort & Spa HOA will be
responsible to perform the maintenance activities and to ensure adequate funding.
The City of Carlsbad Watershed Protection, Stormwater Management, and
Discharge Control Ordinance require ongoing maintenance of BMPs to ensure the
proper function and operation of theses BMPs.
6.1.2 - Annual Operations & Maintenance Costs - CDS Treatment Unit
- Periodic Inspection, Maintenance and Monitoring = $800 x 1
- Annual Cleanout Cost = $1,000 x 1
CDS Subtotal = $1,800
10% Contingency = $180
Approximate Total Annual Maintenance Costs = $1,980
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