HomeMy WebLinkAboutCT 06-13; Tabata 10; Storm Water Management Plan; 2014-07-15Major Stormwater Management Plan
(Major SWMP) SWMP
For
Tabata 10
(CT 06-13)
Dvvg's 472-7C and 472-7D
SWMP 14-01
Preparation/Revision Date:
July 15,2014
Prepared for:
Lennar Homes-California Coastal Division
25 Enterprise
Aliso Viejo, CA 92656
(949) 349-8032
W.O. 2167-0125
Prepared by:
Hunsaker and Associates
9707 Waples Street
San Diego, CA 92121
Tlie selection, sizing, and preliminary design of stormwater treatment and other control measures
ill this plan have been prepared under the direction of the following Registered Civil Engineer
and meet the requirements of Regional Water Quality Control Board Order R9-2007-0001 and —j
subsequent amendments.
0(..Ls.C7^7 ?/^/i-^
Alisa Vlalpando, RCEftf 47945 Date
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The Stormwater Management Plan (Major SWMP) must be completed in its entirety and
accompany applications to the City for a permit or approval associated with certain types of
development projects. To determine whether your project is required to submit a SWMP, please
reference the City's Stormwater Standards Questionnaire.
Project Name: Tabata 10
Project Location: Southwest of El Camino Real, southeast of
Camino Hills Drive, northeast of Brovming
Road, and northwest of Bryant Drive within
the City of Carlsbad, California.
Permit Number (Land Development Projects):
Woric Authorization Number (CIP only):
Applicant: Lennar Homes - Califomia Coastal Division
Applicant's Address: 25 Enterprise
Aliso Viejo, CA 92656
Plan Prepared By (Leave blank if same as
applicant):
Hunsaker and Associates - San Diego
Preparer's Address: 9707 Waples Street
San Diego, CA 92121
Date: July 15, 2014
The City's Standard Urban Stormwater Management Plan (SUSMP) requires all applications for
a permit or approval associated with a Land Disturbance Activity to be accompanied by a Storm
Water Management Plan (SWMP) (section 67.806.b). The purpose of the SWMP is to describe
how the project will minimize the short and long-term impacts on receiving water quality.
Projects that meet the criteria for a priority development project are required to prepare a SWMP.
Completion of the following checklists and attachments will fulfill the requirements of a SWMP
for the project listed above.
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STEPl
The City's Standard Urban Stormwater Management Plan (SUSMP) requires that new
development and significant redevelopment projects submit a completed Stormwater Standards
Questionnaire. The results of the questionnaire will determine if the project is subject to
'Standard Stormwater Requirements' or to 'Priority Development Project Requirements'. If the
project meets Priority Development Project (PDP) requirements, the project must submit a
Stormwater management Plan (SWMP to demonstrate compliance with the City's SUSMP)
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auaicx I u
CITY
CARLSBAD
O F
STORM WATER
STANDARDS
QUESTIONNAIRE
E-34
Development Services
Land Development Engineering
1635 Faraday Avenue
760-602-2750
www.carlsbadca.gov
INSTRUCTIONS:
To address post-development pollutants that may be generated from development projects, the City requires that new development and
significant redevelopment priority projects incorporate Permanent Storm Water Best Management Practices (BMP's) into the project
design per the City's Standard Urban Stormwater Management Plan (SUSMP). To view the SUSMP, refer to the Engineering Standards
(Volume 4, Chapter 2) at www.carlsbadca.qov/standards.
Initialiy this questionnaire must be completed by the applicant in advance of submitting for a development application (subdivision,
discretionary permits and/or constmction permits). The results of the questionnaire determine the level of storm water standards that
must be applied to a proposed development or redevelopment project. Depending on the outcome, your project will either be subject to
'Standard Stormwater Requirements' or be subject to additional criteria called 'Priority Development Project Requirements'. Many
aspects of project site design are dependent upon the storm water standards applied to a project.
Your responses to the questionnaire represent an Initial assessment of the proposed project conditions and impacts. City staff has
responsibility for making the final assessment after submission of the development application. If staff determines that the questionnaire
was incorrectly filled out and is subject to more stringent storm water standards than initially assessed by you, this will result In the return
ofthe development application as incomplete. In this case, please make the changes to the questionnaire and resubmit to the City.
If you are unsure about the meaning of a question or need help in determining how to respond to one or more of the questions, please
seek assistance from Land Development Engineering staff.
A separate completed and signed questionnaire must be submitted for each new development application submission. Only one
completed and signed questionnaire is required when multiple development applications for the same project are submitted concurrently.
In addition to this questionnaire, you must also complete, sign and submit a Project Threat Assessment Form with construction permits
for the project.
Please start by completing Step 1 and follow the instructions. When completed, sign the form at the end and submit this with your
application to the city.
STEP 1
TO BE COMPLETED FOR ALL PROJECTS
To determine if your project is a priority development project, please answer the following questions:
YES NO
1. Is your project LIMITED TO constructing new or retrofitting paved sidewalks, bicycle lanes or trails that meet
the following criteria: (1) Designed and constructed to direct storm water runoff to adjacent vegetated areas, or
other non-erodible permeable areas; OR (2) designed and constructed to be hydraulically disconnected from
paved streets or roads; OR (3) designed and constructed with permeable pavements or surfaces in
accordance with USEPA Green Streets guidance?
X
2. Is your project LIMITED TO retrofitting or redeveloping existing paved alleys, streets, or roads that are
designed and constructed in accordance with the USEPA Green Streets guidance? X
Ifyou answered "yes" to one or more ofthe above questions, then your project Is NOT a priority development project and therefore is
NOT subject to the stomi water criteria required for priority development projects. Go to step 4, mark the last box stating "my
project does not meet PDP requirements" and complete applicant information.
If you answered "no" to both questions, then go to Step 2.
E-34 Page 1 of 3 Effective 6/27/13
CITY OF
CARLSBAD
STORM WATER
STANDARDS
QUESTIONNAIRE
E-34
Development Services
Land Development Engineering
1635 Faraday Avenue
760-602-2750
www.carlsbadca.gov
STEP 2
TO BE COMPLETED FOR ALL NEW OR REDEVELOPMENT PROJECTS
To determine if your project is a priority development project, please answer the following questions: YES NO
1. Is your project a new development that creates 10,000 square feet or more of impervious surfaces collectively
over the entire project site? This includes commercial, industrial, residential, mixed-use, and public
development projects on public or private land.
X
2. Is your project creating or replacing 5,000 square feet or more of impervious surface collectively over the entire
project site on an existing site of 10,000 square feet or more of Impen/ious surface? This includes commercial,
industrial, residential, mixed-use, and public development projects on public or private land.
X
3. Is your project a new or redevelopment project that creates 5,000 square feet or more of impervious surface
collectively over the entire project site and supports a restaurant? A restaurant is a facility that sells prepared
foods and drinks for consumption, including stationary lunch counters and refreshment stands selling prepared
foods and drinks for immediate consumption.
X
4. Is your project a new or redevelopment project that creates 5,000 square feet or more of impervious surface
collectively over the entire project site and supports a hillside development project? A hillside development
project includes development on any natural slope that is twenty-five percent or greater X
5. Is your project a new or redevelopment project that creates 5,000 square feet or more of impervious surface
collectively over the entire project site and supports a parking lot. A pari<ing lot is a land area or facility for the
temporary partying or storage of motor vehicles used personally for business or for commerce. X
6. Is your project a new or redevelopment project that creates 5,000 square feet or more of impervious surface
collectively over the entire project site and supports a street, road, highway freeway or driveway? A street,
road, highway, freeway or driveway is any paved impervious surface used for the transportation of
automobiles, trucks, motorcycles, and other vehicles.
X
7. Is your project a new or redevelopment project that creates or replaces 2,500 square feet or more of
impervious surface collectively over the entire site, and discharges directly to an Environmentally Sensitive
Area (ESA)? "Discharging Directly to" includes flow that is conveyed overiand a distance of 200 feet or less
from the project to the ESA, or conveyed in a pipe or open channel any distance as an isolated flow from the
project to the ESA (i.e. not commingles with flows from adjacent lands).*
X
8. Is your project a new development that supports an automotive repair shop? An automotive repair shop is a
facility ttiat is categorized in any one of the following Standard Industrial Classification (SIC) codes: 5013,
5014, 5541, 7532-7534, or 7536-7539. X
9. Is your project a new development that supports a retail gasoline outlet (RGO)? This category includes RGO's
that meet the following criteria: (a) 5,000 square feet or more or (b) a project Average Daily Traffic (ADT) of
100 or more vehicles per day.
X
10. Is your project a new or redevelopment project that results In the disturbance of one or more acres of land and
are expected to generate pollutants post construction? X
11.1s your project located within 200 feet of the Pacific Ocean and (1) creates 2,500 square feet or more of
impervious surface or (2) increases impervious surface on the property by more than 10%? X
If you answered "yes" to one or more of the above questions, you ARE a priority development project and are therefore subject to
implementing structural Best Management Practices (BMP's) in addition to implementing Standard Storm Water Requirements such
as source control and low impact development BMP's. A Storm Water Management Plan (SWMP) must be submitted with your
application(s) for development. Go to step 3 for redevelopment projects. For new projects, go to step 4 at the end of this
questionnaire, check the "my project meets PDP requirements" box and complete applicant information.
If you answered "no" to all of the above questions, you ARE NOT a priority development project and are therefore subject to
implementing only Standard Storm Water Requirements such as source control and low impact development BMP's required for all
development projects. A Storm Water Management Plan (SWMP) is not required with your application(s) for development. Go to step
4 at tiie end of this questionnaire, check tiie "my project does not meet PDP requirements" box and complete applicant
information.
E-34 Page 2 of 3 Effective 6/27/13
Tabata 10
«|.
^ CITY OF
CARLSBAD
STORM WATER
STANDARDS
QUESTIONNAIRE
E-34
Development Services
Land Development Engineering
1635 Faraday Avenue
760-602-2750
www.carlsbadca.gov
STEP 3
TO BE COMPLETED FOR REDEVELOPMENT PROJECTS THAT ARE PRIORITY DEVELOPEMENT PROJECTS ONLY Complete the questions below regarding your redevelopment project: YES NO
Does the redevelopment project result In the creation or replacement of impervious surface in an amount of less than
50% of the surface area ofthe previously existing development? X
If you answered "yes," the structural BMP's required for Priority Development Projects apply only to the creation or replacement of
impervtous surface and not the entire development. Go to step 4, check the "my project meets PDP requirements" box and
complete applicant information.
If you answered "no," the structural BMP's required for Priority Development Projects apply to the entire devetopment. Go to step 4,
check the "my project meets PDP requirements" box and complete applicant Information.
STEP4
CHECK THE APPROPRIATE BOX AND COMPLETE APPLICANT INFORMATION
•
My projsct meets PRIORITY DEVELOPMENT PROJECT (PDP) requirements and must comply with additional stormwater
criteria per the SUSMP and I understand I must prepare a Storm Water Management Plan for submittal at time of application.
I understand flow conlrol (hydromodification) requiremenls may apply to my project. Refer to SUSMP for details.
My project does not meet PDP requirements and must only comply with STANDARD STORMWATER REQUIREMENTS per
the SUSMP. As part of these requirements, I will Incorporate low impact development strategies throughout my project.
Applicant Information and Signature Box
Addross*
SE CORNER CAMINO HILLS DRIVE & EL CAMINO REAL Applicant Name:
Accessor's Parcel Number(s): 212-050-32 and 212-050-33
"Lt7i/iof)/hyyy~> cy{ Applicant Tille:,
Date:
p/r. 7^^•>-,f^/frtX7y' 77x7^c7
This Box for City Use Only
City Concunr^nce: YES NO
By:
Date:
Project ID:
* Environmentally Sensitive Areas include but are not limited to all Clean Water Acl Section 303(d) impaired water bodies; areas
designated as Areas of Special Biological Significance by the State Water Resources Conlrol Board (Water Quality Control Plan forthe
San Diego Basin (1994) and amendments); water bodies designated wilh the RARE beneficial use by the Stale Water Resources
Conlrol Board (Water Quality Control Plan for the San Diego Basin (1994) and amendments); areas designated as preserves or their
quivalent under the Multi Species Conservation Program wilhin the Cities and County of San Diego; and any other equivalent
environmentally sensitive areas which have been identified by the Copermittees.
E-34 Page 3 of 3 Effective 6/27/13
STEP 2
PROJECT STORMWATER QUALITY DETERMINATION
Total Project Site Area 10.41 (Acres)
Estimated amount of disturbed acreage: 9.65 (Acres)
(If>l acre, you must also provide a WDID number from the SWRCB) WDID: TBD
Complete A through C and the calculations below to determine the amount of impervious
surface on your project before and after construction.
A. Total size of project site: 10.41 (Acres)
B. Total impervious area (mcluding roof tops) before construction 0.37 (Acres)
C. Total impervious area (including roof tops) after construction 5.27 (Acres)
Calculate percent impervious before construction: B/A 3.54%
Calculate percent unpervious after construction: C/A 50.62%
Please provide detailed descriptions regarding the following questions:
3
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TABLE 2: PROJECT SPECIFIC STORMWATER ANALYSIS
1. I Please provide a brief description of the project.
The proposed Tabata 10 project will consist of 26 detached single-family swelling units
within a 10.41 acre site. The site is located within the City of Carlsbad, California and is
bound by El Camino Real to the northeast, Cammo Hills Drive to the northwest, and
developed residential areas to the southwest and southeast. See Vicinity Map in Attachment
A.
The proposed onsite improvements to the site will include construction of 26 residential
homes along with public roads and associated utility improvements typical of a residential
development. Woric at the site will also include grading throughout and will include
reconfiguration of the northern end of Camino Hills Drive. A linear basin along the
northeastem boLmdary of the site adjacent to El Camino Real will be constructed for use as
detention basin as well as a water quality and hydromodification feature
2. I Describe the current and proposed zoning and land use designation.
Zoning:
Ex: Planned community
Pr: Family Residential (R-l)
Land use
Ex: Graded, Undeveloped
Pr: Low-Medium Density Residential (RLM)
3. I Describe the pre-project and post-project topography of the project. (Show on Plan)
The existing site is vacant except for a portion of Camino Hills Drive along the northwest
boundary which extends from Browning Road to El Camino Real. The site has been mass
graded and slopes towards the northeastern boundary along El Camino Real with an
approximate slope of 5%. A small hill also exists along the northwest boundary and peaks at
an elevation of about 128 feet with a base of about 95 feet. Runoff along the northem
portion of Camino Hills Drive drains towards and outlets into El Camino Real via two curb
outlets. This mnoff then drains south and is collected by an existing inlet located on El
Camino Real. Approximately 1.24 acres at the westem comer of the site drains towards an
existing inlet located along Camino Hills Drive.
Generally speaking, much of the existing drainage pattems will remain in the post
development condition. The majority of the site will continue to drain towards the
northeastem boundary of the site. Street runoff from the Camino Hills Drive loop will be
collected with a single inlet placed at the sump location along the northem side of Camino
Hills Drive and discharge into the proposed basm adjacent to El Camino Real. The proposed
improvements will minimize redirection of drainage areas.
4. Describe the soil classification, permeability, erodibility, and depth to groimdwater for
LID and Treatment BMP consideration. (Show on Plan). If mfiltration BMPs are
proposed, a Geotechnical Engmeer must certify infiltration BMPs in Attachment E.
Accorduig to the NRCS Web Soil Survey, the soils on site chiefly consist of Altamont clay
and small areas of loamy fine sand with hydrologic soil types "C and D". Type C soils are
categorized as having a slow infiltration rate when thoroughly wet. Type D soils are
categorized as having a very slow infiltration rate when thoroughly wet. Both onsite and
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offsite areas contain C and D soils. The erodibility factors onsite have an rating of 0.24.
Erosion factor (K) indicates the susceptibility of a soil so sheet and rill erosion by water.
Values of K range from 0.02 (least erosive) to 0.69 (most erosive).
No infiltration facilities will be proposed for this site. Therefore, groundwater is not an issue
for this development.
5. I Describe if contaminated or hazardous soils are within the project area. (Show on Plan)
Hazardous soils are not known to exist onsite.
6. I Describe the existing site drainage and natural hydrologic features. (Show on Plan)
Refer to Item 3 above.
7. Describe site features and conditions that constrain, or provide opportunities for
stormwater control, such as LID features.
Area and hydraulic head are available and allow the implementation of the proposed basin to
act as a water quality/ hydromodification basin as well as attenuate peak flow detention. The
basin's location downstream of the proposed developed areas will allow all ranoff and its
pollutants to be treated by the basin.
8. I Is this project within the environmentally sensitive areas as defined on the city maps?
• Yes M No
9. I Is this an emergency project?
• Yes M No
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CHANNELS & DRAINAGES
Complete the following checklist to determine if the project includes work in channels.
TABLE 3: PROJECT SPECIFIC STORMWATER ANALYSIS
No. CRITERIA YES NO N/A COMMENTS
1. Will the project include work in channels? • u IfYESgoto 2 If
NO go to 13.
2. Will the project increase velocity or volume
of downstream flow?
• • • If YES go to 6.
3. Will the project discharge to unlined
channels? u u u IfYESgoto. 6.
4. Will the project increase potential sediment
load of downstream flow? u u u If YES go to 6.
5. Will the project encroach, cross, realign, or
cause other hydraulic changes to a stream
that may affect downstream channel
stability?
n u u IfYESgoto 8.
6. Review channel lining materials and design
for stream bank erosion. u u u Continue to 7.
7. Consider channel erosion control measures
within the project limits as well as
downstream. Consider scour velocity.
u u u Continue to 8.
8. Include, where appropriate, energy
dissipation devices at culverts.
• • • Continue to 9.
9. Ensure all transitions between culvert
outlets/headwalls/wingwalls and channels are
smooth to reduce turbulence and scour.
u u u Continue to 10.
10. Include, if appropriate, detention facilities to
reduce peak discharges. u • u Continue to 11.
11. "Hardening" natural downstream areas to
prevent erosion is not an acceptable
technique for protecting channel slopes,
unless pre-development conditions are
determined to be so erosive that hardening
would be required even in the absence of the
proposed development.
u u u Continue to 12.
12. Provide other design principles that are
comparable and equally effective. u u u Continue to 13.
13. End
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STEP 3
HYDROMODIFICATION DETERMINATION
I EndofPeCTswoMatrw I
FIGURE M. HMP Applicabilin-Detemiination
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STEP 4
POLLUTANTS OF CONCERN DETERMINATION
WATERSHED
Please check the waters led(s) for the project.
• San Juan 901 • Santa Margarita 902 • San Luis Rey 903 lEI Carlsbad 904
• San Dieguito 905 • Penasquitos 906 • San Diego 907 • Sweetwater 909
• Otay 910 • Tijuana 911 • Whitewater 719 • Clark 720
• West Salton 721 • Anza Borrego 722 • Imperial 723
http://vyww.waterboards.ca.gov/sandiego/water_issues/progranis/basin_plan/index.shtml
HYDROLOGIC SUB-AREA NAME AND NUMBER(S)
Number Name
904.31 Agua Hedionda Hydrologic Subarea
http://www.waterboards.ca.gov/sandiego/water issues/programs/basinjplan/index.shtml
SURFACE WATERS that each project discharge point proposes to discharge to. List the
SURFACE WATERS
(river, creek, sfream, etc.)
Hydrologic
Unit Basin
Number
Impairment(s) listed [303(d) listed
waters or waters with established
TMDLs]
Distance to
Project
Agua Hedionda Creek 904.31 manganese, selenium, sulfates,
TDS
0.78 miles
Agua Hedionda Lagoon 904.31 bacteria, sediment/siltation 2.11 miles
http://www.waterboards.ca.gov/water_issues/programs/tmdl/docs/ 303dlists2Q06/epa/r9 06 303d
reqtmdls.pdf
GROUND WATERS
Ground
Waters
Hydrologic
Unit Basin
Number MUN AGR IND PROC CWR FRESH POW RECI REC2 BIOL WARM COLD WILD RARE SPWN Los
Monos
904.31 o o o
http://www.waterboards.ca.gov/sandiego/water_issues/progranis/basui_plan/mdex.shtml
+ Excepted from Municipal • Existing Beneficial Use °Potential Beneficial Use
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PROJECT ANTICIPATED AND POTENTIAL POLLUTANTS
Using Table 6, identify pollutants that are anticipated to be generated from the proposed
priority project categories. Pollutants associated wdth any hazardous material sites that have
been remediated or are not threatened by the proposed project are not considered a
pollutant of concern.
TABLE 6: ANTICIPATED AND POTENTIAL POLLUTANTS GENERATED BY LAND
USE TYPE
General Pollutant categories
PDP
Categories Sediments Nutrients Heavy
Metals
Organic
Compounds
Trash &
Debris
Oxygen
Demanding
Substances
Oil&
Grease
Bacteria
&
Viruses
Pesticides
Detached
Residential
I^evelopment
X X X X X X X
Attached
Residential
Development
X X X p(i) p(2) P X
Commercial
Development 1
acre or greater
p(l) p(l) p(2) X p(5) X p(3) p(5)
Heavy industry
/industrial
development
X X X X X X
Automotive
Repair Shops
X X X
Restaurants X X X X
Hillside
Development
>5,000 ftz
X X X X X X
Parking Lots pd) p(l) X X pd) X pd)
Retail Gasoline
Outlets
X X X X X
Slrccls, higliwjiys
& Krccwiivs
X X X p(5^ X
X = anticipated
P = potential
(1) A potential pollutant if landscaping exists on-site.
(2) A potential pollutant if the project mcludes uncovered parkmg areas.
(3) A potential pollutant if land use involves food or animal waste products.
(4) Including petroleum hydrocarbons.
(5) Including solvents.
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PROJECT POLLUTANTS OF CONCERN SUMMARY TABLE
Please summarize the identified project pollutants of concern by checking the appropriate
boxes in the table below and list any surface water impairments identified. Pollutants
anticipated to be generated by the project, which are also causing impairment of receiving
waters, shall be considered the primary pollutants of concem. For projects where no
primary pollutants of concern exist, those pollutants identified as anticipated shall be
considered secondary pollutants of concem.
TABLE 7: PROJECT POLLUTANTS OF CONCERN
Pollutant Category
Anticipated
(X)
Potential
(P) Surface Water Impairments
Sediments X Sediment/siltation
Nutrients X P TDS
Heavy Metals X Manganese, Selenium
Organic Compounds X None
Trash & Debris X None
Oxygen Demanding
Substances
X P Sulfates
Oil & Grease X None
Bacteria & Viruses X Bacteria
Pesticides X None
10
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STEPS
LID AND SITE DESIGN STRATEGIES
Each numbered item below is a Low Impact Development (LID) requirement of the SUSMP.
Please check the box(s) under each number that best describes the LID BMP(s) and Site
Design Strategies selected for this project.
TABLE 8: LID AND SITE DESIGN
1. Conserve natural Areas, Soils, and Vegetation
• Preserve well draining soils (Type A or B)
• Preserve Significant Trees
• Preserve critical (or problematic) areas such as floodplains, steep slopes, wetlands, and
areas with erosive or unstable soil conditions
S Other. Description: Preserve as much of the slopes adjoining the Camino Hills subdivision.
2. Minimize Disturbance to Natural Drainages
• Set-back development envelope from drainages
• Restrict heavy construction equipment access to planned green/open
space areas
• Other. Description:
3. Minimize and Disconnect Impervious Surfaces (see 5)
• Clustered Lot Design
Items checked in 5?
• Other. Description:
4. Minimize Soil Compaction
Restrict heavy construction equipment access to planned green/open
space areas
• Re-till soils compacted by construction vehicles/equipment
• Collect & re-use upper soil layers of development site containing organic
Materials
13 Other. Description: Compaction of basin area shall be minimized to maintain effectiveness.
5. Drain Runoff from Impervious Surfaces to Pervious Areas
LID Street & Road Design
• Curb-cuts to landscaping
• Rural Swales
• Concave Median
• Cul-de-sac Landscaping Design
• Other. Description:
LID Parking Lot Design
• Permeable Pavements
11
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• Curb-cuts to landscaping
• Other. Description:
LID Driveway. Sidewalk. Bike-path Design
• Permeable Pavements
Pitch pavements toward landscaping
• Other. Description:
LID Building Design
• Cisterns & Rain Barrels
• Downspout to swale
• Vegetated Roofs
Other. Description: Discharge downspouts to adjacent landscaped area.
LID Landscaping Design
• Soil Amendments
• Reuse of Native Soils
Smart Irrigation Systems
• Street Trees
• Other. Description:
6. Minimize erosion from slopes
Disturb existing slopes only when necessary
• Minimize cut and fill areas to reduce slope lengths
^ Incorporate retaining walls to reduce steepness of slopes or to shorten slopes
• Provide benches or terraces on high cut and fill slopes to reduce concentration
of flows
• Rounding and shaping slopes to reduce concentrated flow
Collect concentrated flows in stabilized drains and channels
• Other. Description:
12
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STEP 6
SOURCE CONTROL
Please complete the checklist on the following pages to determine Source Control BMPs.
Below is instraction on how to use the checklist. (Also see instructions Appendix 1 of the
Carlsbad SUSMP)
1. Review Column 1 and identify which of these potential sources of stormwater pollutants
apply to your site. Check each box that applies.
2. Review Column 2 and incorporate all of the corresponding applicable BMPs in your
Source Control Exhibit in Attachment B.
3. Review Columns 3 and 4 and uicorporate all of the corresponding applicable permanent
controls and operational BMPs in a table in your Project-Specific SUSMP.
4. Use the format in Table 9 below to summarize the project Source Control BMPs. Incorporate
all identified Source Control BMPs in your Source Control Exhibit in
Attachment B.
TABLE 9: PROJECT SOURCE CONTROL BMPS
Potential source of
runoffpollutants
Permanent
source control BMPs
Operational
source control BMPs
On-site storm drain
inlets
Mark all inlets with the words "No
Dumping! Flows to Bay" or
similar.
Maintain and periodically
repaint or replace inlet
markings.
Landscape/Outdoor
Pesticide Use
Design landscaping to minimize
irrigation and runoff, to promote
infiltration where appropriate, and
to minimize the use of fertilizers
and pesticides that can contribute
to stormwater pollution.
Where landscaped areas are used
to retain or detain stormwater,
specify plants that are tolerant of
saturated soil conditions.
Consider using
plants, especially
hardscape.
pest-resistant
adjacent to
To insure successful
establishment, select plants
appropriate to site soils, slopes,
climate, sun, wind, rain, land use,
air movement, ecological
consistency, and plant interactions.
Maintain landscaping using
minimum or no pesticides.
See applicable operational
BMPs in Fact Sheet SC-41,
"Building and Grounds
Maintenance," in the CASQA
Stormwater Qualify
Handbooks at
www.cabmphandbooks.com.
Roofing, gutters, and
trim.
Avoid roofing, gutters, and trim
made of copper or other
13
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unprotected metals that may leach
into runoff.
Sidewalks Sidewalks shall be swept
regularly to prevent the
accumulation of litter and
debris. Debris from pressure
washing shall be collected to
prevent entry into the storm
drain system. Washwater
containing any cleaning agent
or degreaser shall be collected
and discharged to the sanitary
sewer and not discharged to a
storm drain
14
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Describe your specific Source Control BMPs in an accompanying narrative, and explain any
special conditions or situations that required omittuig Source Control BMPs or substituting
altematives.
The public onsite storm drain system will consist of one curb inlet discharging into the proposed
water quality/HIVIP (bioretention) basin. The inlet will collect all runoff from the developed
portion of the site. The discharge point into the basin will include rip rap for energy dissipation.
Maintenance for the collection of any trash and debris accumulated at the inlet or rip will be
performed by the City of Carlsbad.
The on-lot landscaping will be maintained by the respective homeowner. The open spaces
throughout the site including the proposed water quality (bioretention) basin will be
maintained by the HOA which will be created for Tabata 10. The (bioretention) basin will
include specific features for water quality treatment, hydromodification, and peak flow
detention. Landscaping within the open spaces will be coordinated with the Landscape
Architect. Landscaping will be designed to withstand ponding yet tolerate periods with low
water. Landscaping will also be native or similar, that does not require fertilizers or pesticides.
Landscaping shall be chosen according to site soils, slopes, climate, sun, wind, rain, land use,
and air movement.
Home construction will discourage the use of copper or other unprotected metals which may
leach and contaminate runoff.
The City of Carlsbad will provide regular street sweeping and collection of miscellaneous trash
and debris accumulated throughout the onsite public areas.
15
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IF THESE SOURCES
WILL BE ON THE
PROJECT SITE...
.THEN YOUR STORMWATER CONTROL PLAN SHOULD INCLUDE THESE SOURCES CONTROL BMPs
Potential Sources of
Runoff Pollutants
Permanent Controls - Show on
Source Control Exhibit, Attachment
B
Permanent Controls - List in SWMP
Table and Narrative
Operational BMPs - Include in
SWMP Table and Narrative
A. On-site storm drain
inlets
• Location of inlets. Mark all inlets with the words "No
Dumping! Flows to Bay" or similar.
lEI Maintain and periodically repaint or
replace inlet markings.
• Provide stormwater pollution
prevention information to new site
owners, lessees, or operators.
• See applicable operational BMPs in
Fact Sheet SC-44, "Drainage System
Maintenance," in the CASQA
Stormwater Qualify Handbooks at
www.cabmphandbooks.com
• Include the following in lease
agreements: "Tenant shall not allow
anyone to discharge anything to
storm drains or to store or deposit
materials so as to create a potential
discharge to storm drains."
• B. Interior floor drains
and elevator shaft sump
pumps
• State that interior floor drains and
elevator shaft sump pumps will be
plumbed to sanitary sewer.
• Inspect and maintain drains to
prevent blockages and overflow.
• C. Interior parking
garages
• State that parking garage floor drains
will be plumbed to the sanitary sewer.
• Inspect and maintain drains to
prevent blockages and overflow.
16
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IF THESE SOURCES
WILL BE ON THE
PROJECT SITE...
...THEN YOUR STORMWATER CONTROL PLAN SHOULD INCLUDE THESE SOURCES CONTROL BMPs
1
Potential Sources of
Runoff Pollutants
2
Permanent Controls - Show on
Source Control Exhibit, Attachment
B
3
Permanent Controls - List in SUSMP
Table and Narrative
4
Operational BMPs - Include in
SUSMP Table and Narrative
• D. Need for future
indoor & structural
pest control
• Note building design features that
discourage entry of pests.
• Provide Integrated Pest Management
information to owners, lessees, and
operators.
17
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IF THESE SOURCES
WILL BE ON THE
PROJECT SITE...
...THEN YOUR STORMWATER CONTROL PLAN SHOULD INCLUDE THESE SOURCES CONTROL BMPs
1
Potential Sources of
Runoff Pollutants
Permanent Controls - Show on
Source Control Exhibit, Attachment
B
Permanent Controls - List in SUSMP
Table and Narrative
Operational BMPs - Include in
SUSMP Table and Narrative
S D2. Landscape'
Outdoor Pesticide Use
Note: Should be
consistent with project
landscape plan (if
applicable).
• Show locations of native trees or
areas of shrubs and ground cover to
be undisturbed and retained.
• Show self-retaining landscape
areas, if any.
• Show stormwater treatment
facilities
• State that final landscape plans will
accomplish all of the following:
• Preserve existing native trees, shrubs,
and ground cover to the maximum
extent possible.
M Design landscaping to minimize
irrigation and runoff, to promote
surface infiltration where appropriate,
and to minimize the use of fertilizers
and pesticides that can contribute to
stormwater pollution.
M Where landscaped areas are used to
retain or detain stormwater, specify
plants that are tolerant of saturated
soil conditions.
• Consider using pest-resistant plants,
especially adjacent to hardscape.
• To insure successfiil establishment,
select plants appropriate to site soils,
slopes, climate, sun, wind, rain, land
use, air movement, ecological
consistency, and plant interactions.
S Maintain landscaping using
minimum or no pesticides.
^ See applicable operational BMPs in
Fact Sheet SC-41, "Building and
Grounds Maintenance," in the
CASQA Stormwater Quality
Handbooks at
www.cabmphandbooks.com.
• Provide IPM information to new
owners, lessees and operators.
18
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IF THESE SOURCES
WILL BE ON THE
PROJECT SITE...
...THEN YOUR STORMWATER CONTROL PLAN SHOULD INCLUDE THESE SOURCES CONTROL BMPs
1
Potential Sources of
Runoff Pollutants
2
Permanent Controls - Show on
Source Control Exhibit, Attachment
B
3
Permanent Controls - List in SUSMP
Table and Narrative
4
Operational BMPs - Include in
SUSMP Table and Narrative
• E. Pools, spas, ponds
decorative fountains,
and other water
features.
• Show location of water feature and
a sanitary sewer cleanout in an
accessible area within 10 feet.
• If the local municipality requires pools
to be plumbed to the sanitary sewer,
place a note on the plans and state in
the narrative that this connection will
be made according to local
requirements.
• See applicable operational BMPs in
Fact Sheet SC-72, "Fountain and
Pool Maintenance," in the CASQA
Stormwater Quality Handbooks at
www.cabmphandbooks.com
• F. Food service • For restaurants, grocery stores, and
other food service operations, show
location (indoors or in a covered
area outdoors) of a floor sink or
other area for cleaning floor mats,
containers, and equipment.
• On the drawing, show a note that
this drain will be connected to a
grease interceptor before
discharging to the sanitary sewer.
• Describe the location and features of
the designated cleaning area.
• Describe the items to be cleaned in
this facilify and how it has been sized
to insure that the largest items can be
accommodated.
•
19
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IF THESE SOURCES
WILL BE ON THE
PROJECT SITE...
.THEN YOUR STORMWATER CONTROL PLAN SHOULD INCLUDE THESE SOURCES CONTROL BMPs
1
Potential Sources of
Runoff Pollutants
Permanent Controls - Show on
Source Control Exhibit, Attachment
B
Permanent Controls - List in SUSMP
Table and Narrative
Operational BMPs - Include in
SUSMP Table and Narrative
• G. Refuse areas • Show where site refuse and
recycled materials will be handled
and stored for pickup. See local
municipal requirements for sizes
and other details of refiise areas.
• If dumpsters or other receptacles
are outdoors, show how the
designated area will be covered,
graded, and paved to prevent run-
on and show locations of berms to
prevent runoff from the area.
• Any drains from dumpsters,
compactors, and tallow bin areas
shall be connected to a grease
removal device before discharge to
sanitary sewer.
• State how site refuse will be handled
and provide supporting detail to what
is shown on plans.
• State that signs will be posted on or
near dumpsters with the words "Do
not dump hazardous materials here"
or similar.
• State how the following will be
implemented:
Provide adequate number of
receptacles. Inspect receptacles
regularly; repair or replace leaky
receptacles. Keep receptacles
covered. Prohibit/prevent dumping of
liquid or hazardous wastes. Post "no
hazardous materials" signs. Inspect
and pick up litter daily and clean up
spills immediately. Keep spill control
materials available on- site. See Fact
Sheet SC-34, "Waste Handling and
Disposal" in the CASQA
Stormwater Qualify Handbooks at
www.cabmphandbooks.com
• H. Industrial processes. • Show process area. • If industrial processes are to be
located on site, state: "All process
activities to be performed indoors. No
processes to drain to exterior or to
storm drain system."
• See Fact Sheet SC-10, "Non
Stormwater Discharges" in the
CASQA Stormwater Quality
Handbooks at
www.cabmphandbooks.com
20
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IF THESE SOURCES
WILL BE ON THE
PROJECT SITE...
...THEN YOUR STORMWATER CONTROL PLAN SHOULD INCLUDE THESE SOURCES CONTROL BMPs
Potential Sources of
Runoff Pollutants
Permanent Controls - Show on
Source Control Exhibit, Attachment
B
Permanent Controls - List in SUSMP
Table and Narrative
Operational BMPs - Include in
SUSMP Table and Narrative
• I. Outdoor storage of
equipment or materials.
(See rows J and K for
source control
measures for vehicle
cleaning, repair, and
maintenance.)
• Show any outdoor storage areas,
including how materials will be
covered. Show how areas will be
graded and bermed to prevent run-
on or run-off from area.
• Storage of non-hazardous liquids
shall be covered by a roof and/or
drain to the sanitary sewer system,
and be contained by berms, dikes,
liners, or vaults.
• Storage of hazardous materials and
wastes must be in compliance with
the local hazardous materials
ordinance and a Hazardous
Materials Management Plan for the
site.
• Include a detailed description of
materials to be stored, storage areas,
and structural features to prevent
pollutants from entering storm drains.
Where appropriate, reference
documentation of compliance with the
requirements of local Hazardous
Materials Programs for:
• Hazardous Waste Generation
• Hazardous Materials Release
Response and Inventory
• Califomia Accidental Release
(CalARP)
• Aboveground Storage Tank
• Uniform Fire Code Article 80
Section 103(b) & (c) 1991
Underground Storage Tank
• See Fact Sheet SC-31, "Outdoor
Liquid Container Storage" and SC-
33, "Outdoor Storage of Raw
Materials" in the CASQA
Stormwater Qualify Handbooks at
www.cabmphandbooks.com
21
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• J. Vehicle and
Equipment Cleaning
• Show on drawings as appropriate:
(1) Commercial/industrial facilities
having vehicle /equipment cleaning
needs shall either provide a covered,
bermed area for washing activities or
discourage vehicle/equipment washing
by removing hose bibs and installing
signs prohibiting such uses.
(2) Multi-dwelling complexes shall
have a paved, bermed, and covered car
wash area (unless car washing is
prohibited on-site and hoses are
provided with an automatic shutoff to
discourage such use).
(3) Washing areas for cars, vehicles,
and equipment shall be paved, designed
to prevent run-on to or runoff from the
area, and plumbed to drain to the
sanitary sewer.
(4) Commercial car wash facilities shall
be designed such that no runoff from
the facility is discharged to the storm
drain system. Wastewater from the
facility shall discharge to the sanitary
sewer, or a wastewater reclamation
system shall be installed.
• If a car wash area is not provided,
describe measures taken to discourage
on-site car washing and explain how
these will be enforced.
Describe operational measures to
implement the following (if
applicable):
• Washwater from vehicle and
equipment washing operations shall
not be discharged to the storm drain
system.
• Car dealerships and similar may
rinse cars with water only.
• See Fact Sheet SC-21, "Vehicle and
Equipment Cleaning," in the
CASQA Stormwater Quality
Handbooks at
www.cabmphandbooks.com
22
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• K. Vehicle/Equipment
Repair and
Maintenance
• Accommodate all vehicle
equipment repair and maintenance
indoors. Or designate an outdoor
work area and design the area to
prevent run-on and runoff of
stormwater.
• Show secondary containment for
exterior work areas where motor
oil, brake fluid, gasoline, diesel
fuel, radiator fluid, acid-containing
batteries or other hazardous
materials or hazardous wastes are
used or stored. Drains shall not be
installed within the secondary
containment areas.
• Add a note on the plans that states
either (1) there are no floor drains,
or (2) floor drains are connected to
wastewater pretreatment systems
prior to discharge to the sanitary
sewer and an industrial waste
discharge permit will be obtained.
• State that no vehicle repair or
maintenance will be done outdoors, or
else describe the required features of
the outdoor work area.
• State that there are no floor drains or if
there are floor drains, note the agency
from which an industrial waste
discharge permit will be obtained and
that the design meets that agency's
requirements.
• State that there are no tanks,
containers or sinks to be used for parts
cleaning or rinsing or, if there are, note
the agency from which an industrial
waste discharge permit will be
obtained and that the design meets
that agency's requirements.
In the SUSMP report, note that all of
the following restrictions apply to
use the site:
• No person shall dispose of nor
permit the disposal, directly or
indirectly of vehicle fluids,
hazardous materials, or rinsewater
from parts cleaning into storm drains.
• No vehicle fluid removal shall be
performed outside a building, nor on
asphalt or ground surfaces, whether
inside or outside a building, except
in such a manner as to ensure that
any spilled fluid will be in an area of
secondary containment. Leaking
vehicle fluids shall be contained or
drained from the vehicle
immediately.
• No person shall leave unattended
drip parts or other open containers
containing vehicle fluid, unless such
containers are in use or in an area of
secondary containment.
23
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• L. Fuel Dispensing
Area
•
•
Fueling areas' shall have
impermeable floors (i.e., portland
cement concrete or equivalent
smooth impervious surface) that
are: a) graded at the minimum
slope necessary to prevent ponding;
and b) separated from the rest of the
site by a grade break that prevents
run-on of stormwater to
the maximum extent practicable
Fueling areas shall be covered by a
canopy that extends a minimum of
ten feet in each direction from each
pump. [Alternative: The fueling
area must be covered and the
cover's minimum dimensions must
be equal to or greater than the area
within the grade break or fuel
dispensing area'.] The canopy [or
cover] shall not drain onto the
fueling area.
• The properfy owner shall sweep the
fueling area routinely.
• See the Business Guide Sheet,
"Automotive Service - Service,
Stations" in the CASQA Stormwater
Qualify Handbooks at
www.cabmphandbooks.com.
The fueling area shall be defined as the area extending a minimum of 6.5 feet from the corner of each fuel dispenser or the length at which the hose and nozzle
assembly may be operated plus a minimum of one foot, whichever is greater.
24
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• M. Loading Docks • Show a preliminary design for the
loading dock area, including
roofing and drainage. Loading
docks shall be covered and/or
graded to minimize run-on to and
runoff from the loading area. Roof
downspouts shall be positioned to
direct stormwater away from the
loading area. Water from loading
dock areas should be drained to the
sanitary sewer where feasible.
Direct connections to storm drains
from depressed loading docks are
prohibited.
I I Loading dock areas draining
directly to the sanitary sewer shall
be equipped with a spill control
valve or equivalent device, which
shall be kept closed during periods
of operation.
I I Provide a roof overhang over the
loading area or install door skirts
(cowling) at each bay that enclose
the end of the trailer.
• Move loaded and unloaded items
indoors as soon as possible
• See Fact Sheet SC-30, "Outdoor
Loading and Unloading," in the
CASQA Stormwater Qualify
Handbooks at
www.cabmphandbooks.com
• N. Fire Sprinkler Test
Water
• Provide a means to drain fire sprinkler
test water to the sanitary sewer.
• See the note in Fact Sheet SC-41,
"Building and Grounds
Maintenance," in the CASQA
Stormwater Quality Handbooks at
www.cabmphandbooks.com
25
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• O. Miscellaneous Drain
or Wash Water
• Boiler drain lines
• Condensate drain lines
• Rooftop equipment
• Drainage sumps
13 Roofing, gutters, and
trim
• Boiler drain lines shall be directly or
indirectly connected to the sanitary
sewer system and may not discharge
to the storm drain system.
• Condensate drain lines may discharge
to landscaped areas if the flow is small
enough that runoff will not occur.
Condensate drain lines may not
discharge to the storm dram system.
• Rooftop mounted equipment with
potential to produce pollutants shall
be roofed and/or have secondary
containment.
• Any drainage sumps on-site shall
feature a sediment sump to reduce the
quantify of sediment in pumped water.
M Avoid roofing, gutters, and trim made
of copper or other unprotected metals
that may leach into runoff
13 P. Plazas, sidewalks
and parking lots.
M Plazas, sidewalks, and parking lots
shall be swept regularly to prevent
the accumulation of litter and debris.
Debris from pressure washing shall
be collected to prevent entry into the
storm drain system. Washwater
containing any cleaning agent or
degreaser shall be collected and
discharged to the sanitary sewer and
not discharged to a storm drain.
26
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STEP?
LID AND TREATMENT CONTROL SELECTION
A treatment control BMP and/or LID facility must be selected to treat the project pollutants of
concem identified in Table 7 "Project Pollutants of Concern". A treatment control facility with a
high or medium pollutant removal efficiency for the project's most significant pollutant of
concem shall be selected. It is recommended to use the design procedure in the SUSMP to meet
NPDES permit LID requirements, integrated LID requirements, and flow control requirements.
If your project does not utihze this approach, the project will need to demonstrate compliance
with LID, treatment and flow control requirements. Review Section 2 "Identify Pollutants, BMP
Sizing and Selection" in the SUSMP to assist in determining the appropriate treatment facility
for yoiu- project.
Will this project be utilizing the unified LID design procedure as described in Chapter 4 of the Local
SUSMP? (Ifyes, please jjjjajinent in Attacfiment D following the steps in Chapter 4 of the County SUSMP)
No
If this project is not utilizing the unified LID design procedure, please describe how the ahemative
treatment facilities will comply with applicable LID criteria, stormwater treatment criteria, and
hydromodification management criteria.
• Indicate the project pollutants of concern (POCs) from Table 7 in Column 2 below.
TABLE 10: GROUPING OF POTENTIAL POLLUTANTS of Concern (POCs) by fate
during stormwater treatment
Pollutant Check Course Sediment and Trash Pollutants that tend Pollutants that tend
Project to associate with to be dissolved
Specific fine particles during following treatment
POCs treatment
Sediment X X X
Nutrients X X X
Heavy Metals X X
Organic Compounds X X
Trash & Debris X X
Oxygen Demanding X X
Bacteria X X
Oil & Grease X X
Pesticides X X
27
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• Indicate the treatment facility(s) chosen for this project in the following table.
TABLE 11: GROUPS OF POLLUTANTS and relative effectiveness of treatment
facilities
Pollutants of
Concem
Rioreleiiiioii
Facilities
(LID)
Settling
Hiisins
(Dry
Ponds)
Wet Ponds
and
Consfructed
Wetlands
Infilfration
Facilities
or
Practices
(LID)
Media
Filters
Higher-
rate
biofilters*
Higher-
rate
media
filters*
Trash Racks
& Hydro
-dynamic
Devices
Vegetated
Swales
Course
Sediment
and Trash
High High High High High High High High High
Pollutants
that tend to
associate
with fine
particles
during
freatment
High High High High High Medium Medium Low Medium
Pollutants
that tend to
be dissolved
following
freatment
Medium l.ow Medium High Low Low Low Low Low
• Please check the box(s) that best describes the Treatment BMP(s) and / or LID BMP
selected for this project.
TABLE 12: PROJECT LID AND TC-BMPS
Bioretention Facilities (LID)
Bioretention area
• Flow-through Planter
• Cistem with Bioretention Facilify
Settling Basins (Dry Ponds)
• Extended / dry detention basin with grass / vegetated
lining
• Extended / dry detention basin with impervious lining
Infiltration Facilities or Practices (LID)
• Infiltration basin
• Drywell
• Infiltration trench
Wet Ponds and Constructed Wetlands
• Wet pond / basin (permanent pool)
• Constructed wetland
Vegetated Swales (LID '")
• Vegetated Swale
28
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Media Filters
• Austin Sand Filter
• Delaware Sand Filter
• Multi-Chambered Treatment Train (MCTT)
Higher-rate Biofilters
• Tree-pit-sfyle unit
• Other.
Higher-rate Media Filters
• Vault-based filtration unit with replaceable carfridges
• Other.
Hydrodynamic Separator Systems
• Swirl Concentrator
• Cyclone Separator
Trash Racks
• Catch Basin Insert
• Catch Basin Insert w/ Hydrocarbon boom
• Other.
Self-Treating or Self-Retaining Areas (LID)
• Pervious Pavements
• Vegetated Roofs
Other : Open space, landscaped areas.
(1) Must be designated per SUSMP "Vegetated Swales" design criteria for LID credit (p. 65).
For design guidelines and calculations refer to Chapter 4 "Low Impact Development Design
Guide" in the SUSMP. Please show all calculations and design sheets for all treatment facilities
proposed in Attachment D.
29
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• Create a Constraction Plan SWMP Checklist for your project.
Representative Name: Lester Tucker
Company Name: Lennar Homes- California Coastal Division
Phone Number: (949) 349-8032
Street Address: 25 Enterprise
City / State / Zip: Aliso Viejo CA 92656
Email Address: http://wvyw.lennar.coni/home.asp
Instractions on how to fill out table
1. Number and list each measure or BMP you have specified in your SWMP in
Columns 1 and Maintenance Category ui Column 3 of the table. Leave Column 2
blank.
2. When you submit construction plans, duplicate the table (by photocopy or
electronically). Now fill in Column 2, identifying the plan sheets where the BMPs are
shown. List all plan sheets on which the BMP appears. This table must be shovm on
the front sheet of the grading and improvement plans.
Stormwater Treatment Control and LID BMPs
Description / Type Sheet Maintenance Category Revisions
Bioretention Facility 2
• Please describe why the chosen treatment BMP(s) was selected for this project. For
project utilizing a low performing BMP, please provide a feasibility analysis that
demonstrates utilization of a treatment facility with a high or medium removal efficiency
ranking is infeasible.
The bioretention facility was chosen as the treatment control BMPs for this site because of its
effectiveness in removing pollutants of concem. The proposed facility will treat the primary
pollutants of concem with a medium to high pollutant removal efficiency. Therefore, the
BMPs proposed for this project treat all primary pollutants of concem to the maximum extent
practicable.
Please provide the sizing design calculations for each Drainage Management Area in
Attachment D. Guidelines for design calculations are located in of the SUSMP. To assist in
these calculations a BMP sizing calculator is available for use at the following location:
http://vyww.projectcleanwater.org/htnil/wg_susmp.htnil.
30
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STEPS
OPERATION AND MAINTENANCE
• Please check the box that best describes the maintenance mechanism(s) for this project.
The recorded maintenance agreement shall be included in the Maintenance Plan for this
project (Attachment F).
TABLE 13: PROJECT BMP CATEGORY
CATEGORY SELECTED BMP Description CATEGORY
YES NO
BMP Description
First
Bioretention Facility Second' X Bioretention Facility
Third'
Bioretention Facility
Fourth
Bioretention Facility
Note:
1. A maintenance notification will be required.
2. A recorded maintenance agreement and access easement will be required.
3. The project will be required to establish or be included in a watershed specific
Community Facility District (CFD) for long-term mauitenance.
4. The developer would be required to dedicate the BMP (and the property on which it is
located and any necessary access) to the County.
• Please list all mdividual LID and Treatment Control BMPs (TC-BMPs) incorporated into the
project. Please ensure the "BMP Identifier" is consistent with the legend in Attachment C
"Drainage Management Area Exhibit". Please attach the record plan sheets upon completion
of project and amend the Major SWMP where appropriate. For each type of LID or TC-
BMP provide an inspection sheet in Attachment F "Maintenance Plan".
TABLE 14: PROJECT SPECIFIC LID AND TCBMPS (List all from SWMP )
BMP Identifier Description/Type Sheet
BF-1 Bioretention Facility / WQ-Hydromod-Detention
1 - All Priority Development Projects (PDPs) require a TCBMP.
2 - BMPs designed to treat stormwater (e.g. LID and hydromod) shall be considered TCBMPs.
*For location of BMPs, see approved Record Plan dated / / . Grading Plan XXXXX,
Sheets X, X.
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• Responsible Party for the Construction Phase
Identify the parties responsible for long-term mauitenance of the BMPs identified above and
Source Controls specified in Attachment B.
Developer's Name: Lennar Homes- California Coastal Division
Address: 25 Enterprise
City / State / Zip: Aliso Viejo CA 92656
Email Address: http://vyww.lennar.com/home.asp
Phone Number: (949) 349-8032
Engineer of Work: Hunsaker and Associates - San Diego
Engineer's Phone Number: (858) 558-4500
• Responsible Party for Ongoing Maintenance
Identify the parties responsible for long-term maintenance of the BMPs identified above and
Source Controls specified in Attachment B. include the appropriate written agreement with the
entities responsible for O&M in Attachment F. Please see Chapter 5 "Stormwater Facility
Maintenance" of the County SUSMP for appropriate maintenance mechanisms.
Owner's Name: Lennar Homes- California Coastal Division
Address: 25 Enterprise
City / State / Zip: AUso Viejo CA 92656
Email Address: http://vyvyw.lennar.com/home.asp
Phone Number: (949) 349-8032
• Funding Source
Provide the fimding source or sources for long-term operation and maintenance of each BMP
identified above. Please see Chapter 5 "Stormwater Facility Maintenance" of the County
SUSMP for the appropriate fimding source options. By certifying the Major SWMP the applicant
is certifying that the fimding responsibilities have been addressed and will be transferred to
fiiture ovyners.
The Owner will be responsible for maintaining all BMPs onsite until a Homeowners Association
is established for the Tabata 10 site. At that time, the HOA will be permanently responsible for
maintaining all BMPs.
32
R:\1203\Hyd\REPORTS\SWMP\1203_SWMP-TABATA10.docx
ATTACHMENTS
Please include the following attachments
ATTACHMENT COMPLETED N/A
A Project Location Map •
B Source Control Exhibit •
C Drainage Management Area (DMA)Exhibit •
D BMP Sizmg Design Calculations (Water Quality
and Hydromodification) and TC-BMP/IMP Design
Details
u
E Geotechnical Certification Sheet 1 1
F Maintenance Plan El •
G Treatment Control BMP Certification •
H HMP Exemption Documentation • Kl
I HMP Memo •
Note: Attachments B and C may be combined.
33
R:\1203\Hyd\REPORTS\SWMP\1203_SWMP-TABATA lO.docx
ATTACHMENT A
PROJECT
SITE
ATTACHMENT B
Source Control Exhibit
(See Attachment C)
ATTACHMENT C
Drainage Management Area (DMA) Exhibit
ATTACHMENT D
Sizing Design Calculations and TC-BMP/LID Design Details
Tabata POC 1 DMA Calculations
Pre-Deve oped Condition
POC Neighborhood % Imperviousness Total Area Pervious Area Impervious Area
1 Natural OX 9.27 9.27 0.00
1 Residential 65% 0.00 0.00 0.00
1 Roadway 100% 0.34 0.00 0.34
1 Total 4% 9.61 9.27 0.34
Tabata POC 1 DMA Calculations
Post-Developed Condition
POC Neighborhood % Imperviousness Total Area Pervious Area impervious Area
l-Direct Natural 0% 1.29 1.29 0.00
1-Oirect Residential-Roadway 55% 0.00 0.00 0.00
1-Direct Tennis Courts 100% 0.00 0.00 0.00
1-Direct l-Direct-Totai N/A 1.29 1.29 0.00
1-Basin Slope - Developed 0% 0,58 0,58 0.00
1-Basin Basin OX 0.20 0.20 0.00
1-Basin Roadway - Developed 60% if-"^ 8.78 3.51 5.27
1-Basin 1-Basin-Total N/A ) 9.56 4.29 5.27
1-Total 1-Total-Total N/A / 10.85 5.58 5.27
<y''
+
CM
-110-
'^ kx> p~ii^-^ -1
/
7, I1AP=
7/'^/z*i^
TOP ELEV = 96.3
HDPE LINER TO ELEV 93.65
BOTH SIDES
TYPE 'G-r INLET W/ GfMTE
PER D-8. 13A15. Rltiit=93.65
EMERGENCY OVERfmN
2 - 1.5- ORinCE
9 ELEV=91.80 fl
2
BOTTOM AND SIDE
SLOPE VEGETATION PER
LANDSCAPE PLANS
1.25'
jyPE 'G-r INLET W/GRATE
PER D-8. 13 ie 15. RHi4=92.80
BASE ELEV = 91.3
SOIL MIX*
r-6" GRAVEL (CLASS 2)
PERFORATED PIPE
(UNDERDRAIN) 61X li/IIN.
SLOPE W/RESTRICTING
END CAP DRILL 2' ORIFICE
0 88.3 FL SEE BELOW
FOR FLOW CONTROL ORIRCE
DETAIL
BIORETENTION BASIN
N.T.S.
INSTALL IMPERMEABLE HDPE LINER TO ELEV OF
OVERFLOW (93.65) W7J0INTS WELDED TO PROVIDE
WATER-TIGHT SEAL (12 MIL MIN)
PER GEOTECHNICAL RECOMMENDATION
*BIORETENTION ENGINEERED SOIL LAYER
SHALL BE "SANDY LOAM" MIX W/A/0 MORE
THAN 5% CLAY CONTENT. PERCOLATION
RATE OF 5-10 INCHES7HR SUSTAINED.
CONTRACTOR TO VERIFY RATE PRIOR TO
DEMOBIUZATION.
/TYPE 'G-r CATCH BASIN &
GRATE PER PLAN.
RIM ELEV PER PLAN
j^A> SPECIHED
SOIL MIX
END CAP
(SCREW-ON)
-GRAVB.
4" PERFORATED
UNDERDRAIN DRILL 2" ORIFICE 9 88.3 FL. SEE
BIORETENTION BASIN DETAIL (ABOVE)
FLOW CONTROL ORIFICE DETAIL/
BIORETENTION FACILITY OUTLET
N.T.S.
ATTACHMENT E
Geotechnical Certification Sheet
(Not Applicable- No infiltration facilities are proposed on this project.)
Hydrologic Soil Group—San Diego County Area, California
(Tabata)
473030 473080 473130 473180 473230 473280 473430 473480
33° 8'43"N S
33° 8'32"N [D
473130 473180 473030 473080
Map Scale: 1:2,530 If printed on A landscape (11" x 8.5") sheet
473230 473280
N D Meters
0 35 70 140 210
•Feet
0 100 200 400 600
Map projedion: Web Mercator COmer coonjinates: WGS84 Edge tics: UTM Zone UN WGS84
USDA Natural Resources
Conservation Service
Web Soil Sun/ey
National Cooperative Soil Survey
473530
473530
S 33° 8'43°N
12/31/2013
Page 1 of 4
Hydrologic Soil Group—San Diego County Area, California
(Tabata)
MAP LEGEND
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Rating Polygons
• A
I I A/D
• B/D
• c
• CID
• D
Not rated or not available
Soil Rating Lines
A
A/D
B
BID
^ C
C/D
^ D
* 0 Not rated or not avaiiabie
Soil Rating Points
• A
H A/D
• B
• B/D
il C
B CID
• Q
• Not rated or not available
Water Features
...-^ Streams and Canals
Transportation
i-i-i Rails
Interstate Highways
US Routes
Major Roads
Local Roads
Background
Aerial Photography
MAP INFORMATION
The soil surveys that comprise your AOI were mapped at 1:24,000.
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding ofthe detail of mapping and accuracy of soil line
placement. The maps do not show the small areas of contrasting
soils that could have been shown at a more detailed scale.
Please rely on the bar scale on each map sheet for map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL: http://websoilsurvey.nrcs.usda.gov
Coordinate System: Web Mercator (EPSG:3857)
Maps from the Web Soil Survey are based on the Web Mercator
projection, which preserves direction and shape but distorts
distance and area. A projection that preserves area, such as the
Albers equal-area conic projection, should be used if more accurate
calculations of distance or area are required.
This product is generated from the USDA-NRCS certified data as of
the version date(s) listed below.
Soil Survey Area: San Diego County Area, California
Survey Area Data: Version 7, Nov 15, 2013
Soil map units are labeled (as space allows) for map scales 1:50,000
or larger.
Date(s) aerial images were photographed: May 3, 2010—Jun 19,
2010
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor shifting
of map unit boundaries may be evident.
USDA Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
12/31/2013
Page 2 of 4
Hydrologic Soil Group—San Diego County Area, California Tabata
Hydrologic Soil Group
Hydrologic Soil Group— Summary by Map Unit — San Diego County Area, Califomia (CA638)
Map unit symbol Map unit name Rating Acres in AOi Percent of AOi
AID Altamont clay, 9 to 15
percent slopes
D 1.5 12.7%
AtE Altamont clay, 15 to 30
percent slopes
D 9.5 78.9%
LeE2 Las Flores loamy fine
sand, 15 to 30 percent
slopes, er oded
D 0.2 2.0%
ScB Salinas clay, 2 to 5
percent slopes
C 0.8 6.4%
Totals for Area of Interest 12.0 100.0%
USDA Natural Resources
•™ Conservation Service
Web Soil Survey
National Cooperative Soil Survey
12/31/2013
Page 3 of 4
Hydrologic Soil Group—San Diego County Area, California Tabata
Description
Hydrologic soil groups are based on estimates of runoff potential. Soils are
assigned to one of four groups according to the rate of water infiltration when the
soils are not protected by vegetation, are thoroughly wet, and receive precipitation
from long-duration storms.
The soils in the United States are assigned to four groups (A, B, C, and D) and
three dual classes {AID, BID, and C/D). The groups are defined as follows:
Group A. Soils having a high infiltration rate (low runoff potential) when thoroughly
wet. These consist mainly of deep, well drained to excessively drained sands or
gravelly sands. These soils have a high rate of water transmission.
Group B. Soils having a moderate infiltration rate when thoroughly wet. These
consist chiefly of moderately deep or deep, moderately well drained or well drained
soils that have moderately fine texture to moderately coarse texture. These soils
have a moderate rate of water transmission.
Group C. Soils having a slow infiltration rate when thoroughly wet. These consist
chiefly of soils having a layer that impedes the downward movement of water or
soils of moderately fine texture or fine texture. These soils have a slow rate of water
transmission.
Group D. Soils having a very slow infiltration rate (high runoff potential) when
thoroughly wet. These consist chiefly of clays that have a high shrink-swell
potential, soils that have a high water table, soils that have a claypan or clay layer
at or near the surface, and soils that are shallow over nearly impervious material.
These soils have a very slow rate of water transmission.
If a soil is assigned to a dual hydrologic group {AJD, BID, or C/D), the first letter is
for drained areas and the second is for undrained areas. Only the soils that in their
natural condition are in group D are assigned to dual classes.
Rating Options
Aggregation Metfiod: Dominant Condition
Component Percent Cutoff: None Specified
Tie-break Rule: Higher
USOA Natural Resources Web Soil Survey 12/31/2013
Conservation Service National Cooperative Soil Survey Page 4 of 4
K Factor, Whole Soil—San Diego County Area, California
(Tabata)
473030 473080 473230 473280 473380 473430
33° 8'43"N S
33°8'32"N
473030 473080 473130 473180
Map Scale: 1:2,530 if printed on A landscape (11" x 8.5') sheet
473230
N 0
iMrters
35 70 140 210
Dpeet
0 100 200 400 600
Map projedion: V\feb Menator Comer coonjinates: WGS84 Edge ties: UTM Zone UN WGS84
USDA Natural Resources
'^Sk Conservation Service
Web Soil Survey
National Cooperative Soil Survey
S 33° 8'43"N
12/31/2013
Page 1 of 3
K Factor, Whole Soil—San Diego County Area, Califomia
(Tabata)
MAP LEGEND
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Rating Polygons
• .02
• .05
• .10
• .15
• .17
• .20
• .24
• .28
• .32
• .37
• .43
• .49
1 i .55
• .64
• Not
Soil Rating Lines
^ .02
.05
^ .10
.15
.17
.20
- " .24 Streams and Canals
.28 Transportation
.32 Rails
.37 Interstate Highways
.43 US Routes
A^ 49 Major Roads
.55 Local Roads
.64 Background
0 0 Not rated or not available
Aerial Photography
oil Rating Points • .02
n .05
n .10
• .15
• .17
• .20
• .24
• .28
• .32
0 0
0 0 •
.37
.43
.49
.55
.64
Not rated or not available
Water Features
MAP INFORMATION
The soil surveys that comprise your AOI were mapped at
1:24,000.
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil
line placemenL The maps do not show the small areas of
contrasting soils that could have been shown at a more detailed
scale.
Please rely on the bar scale on each map sheet for map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL: http://websoilsurvey.nrcs.usda.gov
Coordinate System: Web Mercator (EPSG:3857)
Maps from the Web Soil Survey are based on the Web Mercator
projection, which preserves direction and shape but distorts
distance and area. A projection that preserves area, such as the
Albers equal-area conic projection, should be used if more
accurate calculations of distance or area are required.
This product is generated from the USDA-NRCS certified data as
of the version date(s) listed below.
Soil Survey Area: San Diego County Area, California
Survey Area Data: Version 7, Nov 15, 2013
Soil map units are labeled (as space allows) for map scales
1:50,000 or larger.
Date(s) aerial images were photographed: May 3, 2010—Jun
19, 2010
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor shifting
of map unit boundaries may be evident.
USDA Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
12/31/2013
Page 2 of 3
K Factor, Whole Soil—San Diego County Area, Califomia Tabata
K Factor, Whole Soil
K Factor, Wliole Soil— Summary by Map Unit — San Diego County Area, Caiifornia (CA638)
Map unit symbol Map unit name Rating Acres in AOi Percent of AOi
AID Altamont clay, 9 to 15
percent slopes
.24 1.5 12.7%
AtE Altamont clay, 15 to 30
percent slopes
.24 9.5 78.9%
LeE2 Las Flores loamy fine
sand, 15 to 30 percent
slopes, er oded
.28 0.2 2.0%
ScB Salinas clay, 2 to 5
percent slopes
.20 0.8 6.4%
Totals for Area of Interest 12.0 100.0%
Description
Erosion factor K indicates the susceptibility of a soil to sheet and rill erosion by
water. Factor K is one of six factors used in the Universal Soil Loss Equation (USLE)
and the Revised Universal Soil Loss Equation (RUSLE) to predict the average
annual rate of soil loss by sheet and rill erosion in tons per acre per year. The
estimates are based primarily on percentage of silt, sand, and organic matter and
on soil structure and saturated hydraulic conductivity (Ksat). Values of K range from
0.02 to 0.69. Other factors being equal, the higher the value, the more susceptible
the soil is to sheet and rill erosion by water.
"Erosion factor Kw (whole soil)" indicates the erodibility ofthe whole soil. The
estimates are modified by the presence of rock fragments.
Rating Options
Aggregation h/lethod: Dominant Condition
Component Percent Cutoff: None Specified
Tie-break Rule: Higher
Layer Options (Horizon Aggregation hAethod): Surface Layer (Not applicable)
USDA Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
12/31/2013
Page 3 of 3
ATTACHMENT F
Maintenance Plan
(Use Chapter 5 ofthe SUSMP as guidance in developing your Maintenance Plan)
The following is a general outline for to create your project specific Maintenance Plan.
I. Inspection, Maintenance Log and Self-Verification Forms (Examples are provided in
Appendix F ofthe San Diego County SUSMP)
II. Updates, Revisions and Errata
III. Introduction
A. Narrative overview describing the site; drainage areas, routing, and discharge
points; and treatment facilities.
IV. Responsibility for Maintenance
A. General
(1) Name and contact information for responsible individual(s).
(2) Organization chart or charts showing organization of the maintenance
function and location within the overall organization.
(3) Reference to Operation and Maintenance Agreement (if any). A copy of
the agreement should be attached.
(4) Maintenance Funding
(1) Sources of funds for maintenance
(2) Budget category or line item
(3) Description of procedure and process for ensuring adequate
funding for mauitenance
B. Staff Training Program
C. Records
D. Safety
V. Summary of Drainage Areas and Stormwater Facilities
A. Drainage Areas
(1) Drawings showing pervious and impervious areas (copied or adapted firom
initial SWMP).
(2) Designation and description of each drainage area and how flow is routed
to the corresponding facility.
B. Treatment and Flow-Control Facilities
(1) Drawings showing location and type of each facility
(2) General description of each facility (Consider a table if more than two
facilities)
(1) Area drained and routing of discharge.
(2) Facility type and size
VI. Facility Documentation
A. "As-builf drawings of each facility (design drawings in the draft Plan)
B. Manufacturer's data, manuals, and maintenance requirements for pumps,
mechanical or electrical equipment, and proprietary facilities (include a
"placeholder" in the draft plan for information not yet available).
C. Specific operation and maintenance concerns and troubleshooting
VII. Maintenance Schedule or Matrix
A. Maintenance Schedule for each facility with specific requirements for:
(1) Routine inspection and maintenance
(2) Annual inspection and maintenance
(3) Inspection and maintenance after major storms
B. Service Agreement Information
Assemble and make copies of your maintenance plan. One copy must be
submitted to the County, and at least one copy kept on-site. Here are some
suggestions for formatting the maintenance plan:
• Format plans to 81/2 x 11" to facilitate duplication, filing, and handling.
• Include the revision date in the footer on each page.
• Scan graphics and incorporate with text into a single electronic file. Keep the
electronic file backed-up so that copies of the maintenance plan can be made if
the hard copy is lost or damaged.
IVlaintenance Program for Inlet Stenciling
Inspection Frequency/Indications: Reaular Maintenance Insoections
• Before wet season begins (September);
• After wet season (April).
IVlaintenance Indications Maintenance Activities
• Inlet stenciling/signage begins to weather or
fade
• Re-stamp signage
• Broken or damaged structure • Repair or replace signage structure
IVlaintenance Program for Bioretention Basin
Inspection Frequency/Indications: Reaular Insoections
• Before wet season begins (September);
• After wet season (April).
Performance Inspections
• After rainfall events greater than 0.5 inches, or
any rainfall that fills the basin.
Maintenance Indications Maintenance Activities
• Damage to sill, headwall, inlet, outlet, or other
structures
• Repair sill, headwall, inlet, outlet, or other
structures
• Riprap displaced or washed away. • Replace riprap.
• Erosion (ruts, rills, or gullies) found in basin or
downstream of dissipater structure (riprap
apron).
• Re-seed or re-plant barren spots prior to rainy
season. Install erosion blanket on barren spots
if re-vegetation is not successful. Repair Extend
riprap apron, reposition, increase riprap
coverage to fully cover eroded area.
• Over-grown vegetation, emergent woody
vegetation and/or weeds
• Trim vegetation to 12 inches, remove emergent
woody vegetation and weeds.
• Sediment accumulation over 18 inches or fills
25 percent ofthe basin volume, whichever is
greater
• Remove sediment accumulation.
• Standing water in basin during dry weather;
basin does not drain within 72 hours after runoff
event.
• Drain basin. Determine and resolve problems
that are causing the basin to drain improperly. If
basin cannot be drained, or if standing water
persists, notify vector control.
• Evidence of rodent infestation • Abate and control rodents as necessary to
maintain the performance of the facility.
• Trash, debris, or litter present in basin • Remove trash, debris, and litter
Waste Disposal Sediment, other pollutants, and all other waste shall
be properiy disposed of In a licensed landfill or by
another appropriate disposal method in accordance
with local, state, and federal regulations.
IVlaintenance Program for Riprap Energy Dissipaters
Inspection Frequency/Indications: Reaular Insoection - First Year
• Before wet season begins (September);
• After wet season (April).
Reaular Inspection - Subseauent Years
• After wet season begins (April).
Performance Insoection
• After rainfall events greater than 0.5 inches.
Maintenance Indications Maintenance Activities
• Damage to sill, headwall, or other structures a Repair sill, headwall, or other structures
• Riprap displaced or washed away • Replace riprap
• Erosion (ruts, rills, or gullies) found downstream • Extend riprap apron, reposition, increase riprap
of dissipater structure (riprap apron). coverage to fully cover eroded area.
a Over-grown vegetation, emergent woody
vegetation and/or weeds
• Trim vegetation to 6 inches, remove emergent
woody vegetation and weeds
• Sediment accumulation over 3 inches • Remove sediment accumulation
• Trash and litter present in riprap • Remove trash and debris
Waste Disposal Sediment, other pollutants, and all other waste shall
be properiy disposed of in a licensed landfill or by
another appropriate disposal method in accordance
with local, state, and federal regulations.
ATTACHMENT G
Treatment Control BMP Certification
(Executed Upon Approval)
ATTACHMENT H
HMP Exemption Documentation
(Not Applicable)
ATTACHMENT I
HMP Memorandum
1 - Introduction
According to the March 2011 Final Hydromodification Plan (HMP), all priority projects that have
the potential to increase unmitigated peak flows, and that do not directly discharge to exempt
water bodies are required to perform a hydromodification analysis. This project is therefore
required to manage hydromodification impacts.
The site is located within the City of Carlsbad, California and is bound by El Camino Real to the
northeast, Camino Hills Drive to the northwest, and developed residential areas to the
southwest and southeast. (See Figure 1).
The existing site is vacant except for a portion of Camino Hills Drive along the northwest
boundary which extends from Browning Road to El Camino Real. The site has been mass
graded and slopes towards the northeastern boundary along El Camino Real with an
approximate slope of 5%. A small hill also exists along the northwest boundary and peaks at an
elevation of about 128 feet with a base of about 95 feet. Runoff along the northern portion of
Camino Hills Drive drains towards and outlets into El Camino Real via two curb outlets. This
runoff then drains south and is collected by an existing inlet located on El Camino Real.
Approximately 1.24 acres at the western corner of the site drains towards an existing inlet
located along Camino Hills Drive. The Point of Compliance (P0C1) for this project and the
hydromodification analysis was taken as a point along the noilheastern boundary along El
Camino Real. Refer to the Existing Condition Hydromod Exhibit for Tabata 10 located in
Section 4 of this HMP Attachment. Runoff towards the westem corner of the site drains to an
existing inlet located along Camino Hills Drive. Drainage to this point can claim HMP exemption
based on the condition that 1.) the project will not increase the amount of impervious area to the
inlet and 2.) the project will not increase the unmitigated peak flow the inlet.
Development of the site will include the construction of 26 single family residential homes and
adjoining streets. The site will be accessible via Camino Hills Drive which will loop within the
project area. Generally speaking, much of the existing drainage patterns will remain in the post
development condition. The majority of the site will continue to drain towards the northeastern
boundary of the site. Street runoff from the Camino Hills Drive loop will be collected with a
single inlet placed at the sump location along the northem side of Camino Hills Drive and
discharge into the proposed basin adjacent to El Camino Real. This basin will serve as
detention to attenuate developed peak flows below the existing condition flows. Detention basin
calculations are provided in Chapter 6 of the Drainage Study for Tabata 10. The basin will also
include features to address water quality and hydromodification requirements per the City of
Carlsbad SUSMP.
According to the NRCS WebSoil website, the project contains type "D" soils. Therefore,
infiltration is not recommended for this site. Soils information is located in Appendix 2.
The total proposed boundary area for Tabata 10 is 10.41 acres. Tabata 10 will be developed
with 26 single family residential housing lots, open space, streets, and a WQ/hydromodification
basin. This basin will also help in attenuating peak flows to reduce flowrates below existing
condition. The onsite storm drain infrastmcture will consist of storm drain, cleanouts, inlets,
risers, and headwalls sized to convey the 100-year rainfall flow. The onsite street slopes will
average about 1-7.5% and slope towards the northem comer of the site. As briefly mentioned
above, Tabata 10 will also include a basin which will achieve three uses. Due to the increase
imperviousness of the site compared with existing condition, the developed peak flow runoffs
R:\1203\Hyd\REPORTS\SWMP\1203_SWMP-TABATA10.docx
will need to be attenuated to match or lower flows to below existing condition. Therefore, the
basin will aid in achieving peak flow detention. In addition, the basin will help to achieve
compliance with water quality and hydromodification management criteria set per the City of
Carlsbad SUSMP and the NPDES permit. The Inlet within the project boundary will collect
onsite developed flows and direct them towards the basin for treatment. Basin outflow will be
conveyed towards the existing cleanout located along El Camino Real.
Please refer to pre-development and post-development hydromodification exhibits located in
Section 4 of this Hydromodification Management Plan for Tabata 10 Attachment.
The Oceanside precipitation rain gage file was used for this project, which includes 57 years of
precipitation data.
PROJECT
SITE
Figure 1 Vicinity IVIap
R:\1203\Hyd\REPORTS\SWMP\1203_SWMP-TABATA10.docx
2 - Methodology
EPA SWMM Version 5.0 was used to generate a continuous simulation hydrologic model for the
project site during the pre-development and post-development conditions. The analysis
incorporated the following criteria, as required by the County of San Diego Final
Hydromodification Management Plan (HMP):
• Use of a lower threshold of 10% of 02 (0.102), and an upper threshold of OIO.
• Assess the partial duration model so that post-project discharge rates and durations do
not deviate above the pre-project discharge rates and durations by more than 10 percent
or over more than 10 percent of the length of the flow duration curve.
The values that were input into the SWMM model are included in Section 5 of this
Hydromodification IVIanagement Plan for Tabata 10. For the pre-development SWMM model,
the appropriate parameters were entered into the Subcatchment, which represented both the
onsite and offsite watershed areas.
The SWMM program was then run to generate a continuous simulation model of the pre-
development condition. Once the peak flow frequency results were produced within SWMM,
duration statistics for the pre-development condition were developed using Excel by using the
following methods:
The resulting Date, Time, and Flow Rate were copied and pasted from SWMM and into Excel.
A function was created in Excel that looked at every flow rate during the 57-year period and
selected the peak flow rate for each possible 24 hour period. The largest 57 of these peak flow
rates were then selected and placed in order from smallest to greatest and given a rank. These
values represented the peak flow rates for the 57 years of data.
The Cunnane equation was then used to calculate the period of return for each flow rate. The
Cunnane Equation is as follows:
R = (n + 0.2) / (I - 0.4)
Where:
R = Period of Return
n = Total number of years of precipitation
data
i = Individual rank out of n years
The slope of the line between each peak flow rate was then calculated by using the following
equation:
R:\1203\Hyd\REPORTS\SWMP\1203_SWMP-TABATA10.docx
S = (P2-Pi)/(R2-Ri)
Where:
S = Slope
P = Peak flow rate
R = Period of Return
1 = Initial Value
2 = Sequential Value
The 2-year through the 10-year peak flow rates were then determined by plotting the 57 peak
flow rates along the slope and selecting the appropriate peak flow rate where the desired period
of retum occurred. These results produced the pre-development condition values of 0.102 and
OIO.
For the post-development SWMM model, the appropriate parameters were entered into the
Subcatchment, which represents both the onsite and offsite watershed areas. The
Subcatchment was then linked to the post-development ponding area, or Storage Unit. The
depth and corresponding area ofthe Storage Unit was entered manually into the Storage Curve
Editor in order for SWMM to determine the volume. The Storage Unit was then linked to an
outlet, where a Tabular/Depth Rating Curve was selected for the outflow. This option allows the
user to manually enter the drawdown for the Storage Unit. These drawdown values and depths
were entered into the Outlet Rating Curve Editor.
The drawdown calculations were completed separately in Excel. The outfall would be an
embankment with horizontal culverts as the outlets. Therefore, vertical orifices were to be used
for the drawdown calculations. The orifice equation was used for the drawdown calculations,
and is as follows:
~ Q*CAV(2gH)
(Source: Eqn. 6-12, San Diego County Drainage Design Manual)
Where:
C = Orifice Coefficient, based on Table 6-1 of San Diego County Drainage Design Manual
A = Orifice Area (sq ft)
g= 32.2 (ft/s'^2)
H = Head above centroid of orifice (ft)
The drawdown values were calculated per 0.1 feet of depth in the Storage Unit. These values
were copied from Excel and pasted into the Outlet Rating Curve Editor. An Outfall was then
added to the Outlet of the Storage Unit.
Hourly peak flow rates were then generated for the 57 years of data within SWMM. The same
procedure as described above for the pre-development condition was followed in order to
determine the unmitigated post-development 0.102 and OIO.
To determine if the runoff at the point of compliance met hydromodification requirements, the
post-development condition continuous simulation results (date, time, 0) at the Outlet of the
Storage Unit were pasted into Excel.
R:\1203\Hyd\REPORTS\SWMP\1203_SWMP-TABATA10.docx
A flow duration curve was then produced for both the pre-development and post-development
conditions within Excel. The pre-development condition curve was developed by separating the
57 pre-development condition peak flow rates between 0.102 and OIO into 100 separate
events. The frequency of each of the 100 flow rates was determined by using Excel to count the
number of times each of the 100 flow rates was exceeded during the 57 years of continuous
simulation flow rate results. This value was then converted into a percentage. The post-
development condition flow duration curve was developed by using Excel to count the number
of times the post-development continuous simulation flow rates exceeded each ofthe 100 pre-
development condition peak flow rates.
The model would "Pass" if the post-development flow rates did not exceed those during the pre-
development conditions by more than 10 percent or occurred more than 10 percent of the time.
Several iterations were run and the outflow staictures were adjusted until the post-project flow
duration statistics either matched or did not exceed those during the pre-development condition.
R:\1203\Hyd\REPORTS\SWMP\1203_SWMP-TABATA10.docx
3- Results
POC 1 was analyzed for hydromodification impacts.
Table 1 below summarizes the drainage areas to the point of compliance as well as the upper
and lower thresholds from the internal partial duration series method results.
TABLE 1 - Summary of Areas and Flow Thresholds
Drainage Area (ac) Flow
Thresholds
(cfs) Pre-development
Condition
Post-development
Condition
Flow
Thresholds
(cfs)
Impervious
area (ac)
Pervious
Area (ac)
Impervious
area (ac)
Pervious
Area (ac) 0.1 Q2 QIC
POC 1 0.34 9.27 5.27 5.58 0.47 7.39
Although the POC was placed downstream of the proposed onsite basin, the SWMM model which
was developed considered the basins impact and included its specific characteristics such as
bottom surface area, depth, volume, engineered fill data, riser size, and orifice placement along the
riser height. In addition to achieving compliance to hydromodification criteria, the project also
needed to comply with attenuating peak flows to below the existing condition runoff amount and
verified that the existing storm drains design flowrate is not exceeded. Using the basin
characteristics determined on the SWMM model, a detention basin analysis was performed to
verify adequate flow attenuation. Refer to the Tabata 10 Drainage Study (June 2014) prepared by
Hunsaker & Associates San Diego, Inc. forthe detention basin analysis.
The design criteria for the basins' ponding area is listed in Table 2 below. More detailed input
criteria for the SWMM model is located in Section 5. The results from the SWMM model can be
found in Section 6.
R:\1203\Hyd\REPORTS\SWMP\1203_SWMP-TABATA lO.docx
TABLE 2 -Design Criteria for Post-development Ponding Area
TABATA 10 BASIN
LID Underdrain Outlet
Basin bottom Surface Area (sf) 8,821
Orifice Diameter (in) 2.0
Gravel Depth (ft) 1 5
Riser Dimensions
Riser Area (ft) 3' x 1-11"
Riser Rim Height (ft) 1 25
Orifice Placement along Riser
Low Orifice Diameter (in) "1-5
Elevation from Basin Bottom (ft) 0-5
Number of Orifices 2
R:\1203\Hyd\REPORTS\SWMP\1203_SWMP-TABATA lO.docx
TOP ELEV = 96.3
IHDPE LINER TO ELEV 93.65
BOTH SIDES
T/PE 'G-r INLET W/ GRATE
PER D-8. 13&15. RIM=93.65
EMERGENCY OVERFLOW
'2 - 1.5" ORinCE
9 ELEV=91.80 FL
2
BOTTOM AND SIDE
SLOPE VEGETATION PER
LANDSCAPE PLANS
rypE 'G-r INLET W/GRATE
PER D-8. 13 & 15. RIM=92.80
1.25'
W,ijMI,l,l,^,MklM. BASE ELEV = 91.3
PERFORATED PIPE
(UNDERDRAIN) 91X MIN.
SLOPE W/RESTRICTING
END CAP DRILL 2" ORIFICE
9 88.3 FL SEE BELOW
FOR FLOW CONTROL ORIHCE
DETAIL
BIORETENTION BASIN
6" SOIL MIX*
GRAVEL (CLASS 2)
INSTALL IMPERMEABLE HDPE LINER TO ELEV OF
OVERFLOW (93.65) W/JOINTS WELDED TO PROVIDE
WATER-TIGHT SEAL (12 MIL MIN)
PER GEOTECHNICAI. RECOMMENDATION
*BIORETENTION ENGINEERED SOIL LAYER
SHALL BE "SANDY LOAM" MIX W/NO MORE
THAN 5% CLAY CONTENT. PERCOLATION
RATE OF 5-10 INCHES/HR SUSTAINED.
CONTRACTOR TO VERIFY RATE PRIOR TO
DEMOBILIZATION.
N.T.S.
/TYPE 'G-r CATCH BASIN &
GRATE PER PLAN.
RIM OJEV PER PLAN
SPECIHED
SOIL MIX
END CAP
(SCREW-ON)
-GRAVEL
4" PERFORATE)
UNDERDRAIN DRILL 2" ORinCE 9 88.3 FL SEE
BIORETENTION BASIN DETAIL (ABOVE)
FLOW CONTROL ORIFICE DETAIL/
BIORETENTION FACILITY OUTLET
N.T.S.
4 - Hydromodification Exhibits
R;\1203\Hyd\REPORTS\SWMP\1203_SWIVIP-TABATA lO.docx
Tabata POC 1 DIVIA Calculations
Pre-Developed Condition
POC Neighborhood % Imperviousness Total Area Pervious Area Impervious Area
1 Natural 0% 9.27 9.27 0.00
1 Residential 65% 0.00 0.00 0.00
1 Roadway 100% 0.34 0.00 0.34
1 Total 4% 9.61 9.27 0.34
Tabata POC 1 DMA Calculations
Post-Developed Condition
POC Neighborhood % Imperviousness Total Area Pervious Area Impervious Area
1-Direct Natural 0% 1.29 1.29 0.00
1-Direct Residential-Roadway 55% 0.00 0.00 0.00
1-Direct Tennis Courts 100% 0.00 0.00 0.00
1-Direct 1-Direct-Total N/A 1.29 1.29 0.00
1-Basin Slope - Developed 0% 0.58 0.58 0.00
1-Basin Basin 0% 0.20 0.20 0.00
1-Basin Roadway - Developed 60% 8.78 3.51 5.27
1-Basin 1-Basin-Total N/A 9.56 4.29 5.27
1-Total 1-Total-Total N/A 10.85 5.58 5.27
7/15/2*1'^
Tabata POCl Watershed Parameters
Watershed #1-EX
L= 971 ft
A= 9.61 ac
% Impervious 3.54%
W= 431 ft
US Elev= 144 ft
DS Elev= 87 ft
S= 5.9%
Watershed #1 (Basin)-PR
L= 981 ft
A= 9.36 ac
% Impervious 56%
W= 416 ft
US Elev= 144 ft
DS Elev= 85 ft
S= 6.1%
Basin #1
L= 416 ft
A= 0.20 ac
W= 21
US Elev= 85.00 ft
DS Elev= 84.58 ft
S= 0.1%
Watershed #1 (Non-Basin)-PR
L= 745 ft
A= 1.29 ac
% Impervious 0%
W= 75 ft
US Elev= 109 ft
DS Elev= 88 ft
S= 2.8%
5 - Analysis Input Parameters
EXISTING CONDiTlON
R:\1203\Hyd\REPORTS\SWMP\1203_SW/IV!P-TABATA lO.docx
EXISTING CONDITION
Rain Gage Oceanside
Properly Value
Name Oceanside
X-Coordinate 2mooo " <
Y-Coordinate 5666.000
Description
Tag
Rain Format INTENSfTY
Tirtie Interval 1:00"'^
Snow Catch Factor 1.0
Data Source TIMESERIES
TIMESERIES:
- Series Name Oceanside
DATA FILE:
• File Name
- Station ib
• Rain Units IN
User-assigned name of rain gage
R:\1203\Hyd\REPORTS\SW/MP\1203_SWMP-TABATA lO.docx
Subcatchment Basinl
Propertj) Value
Name
X-Coordinale
Y-Coordinate
Description
Tag
Rain Gage
Outlet
Area
Width
% Slope
% Imperv
N-Imperv
N-Perv
Dstore-lmperv
Dstore-Perv
3£Zero-lmperv
Subarea Routing
Percent Routed
Infiltration
Groundwater
Snow Pack
LID Controls
Land Uses
Initial Buildup
Curb Length
iBasinI
1890.923
155^444
j Existing Area
j Oceanside
iPOCIEK
lim
"1431
i3.54
LOI 2
10.05
••[25
OUTLET
Pm
iGREENjiiMPT
INO
j
lo
'ji
INONE
lo ""'^
User-assigned name of subcatchment
R:\1203\Hyd\REPORTS\SWMP\1203_SWMP-TABATA lO.docx
Outfell POClEx
Property Value 1
Name iPOClEx
X-Coofdinate 1740.113
Y-Coordinate 3977.401
Description
Tag
Inflows NO
Treatment NO^'""'
Invert El. 0
Tide Gate NO
Type FREE
Fixed Outfall
Fixed Stage 0
Tidal Outfall
Curve Name M
Time Series Outfall
Series Name K
User-assigned name of outfall
R:\1203\Hyd\REPORTS\SWMP\1203_SWMP-TABATA10.docx
PROPOSED CONDTION
R:\1203\Hyd\REPORTS\SWMP\1203_SWIVIP-TABATA10.docx
LID Outlet #1
ABMP= 8821 sq-ft (Area above engineered fill/bio-retention section)
(It can also be area of Infiltration at the bottom)
Cg= 0.61 (coefficient of discharge of the bottom orifice)
Dorif= 2 in (diameter in inches of the bottom orifice)
Aorlfice= 0.02182 sq-ft (area of orifice in sq-ft)
CsWMM= 0.1510 C coefficient to be inserted into SWIVIM
H-gravel= 1.5 ft Depth ofthe gravel layer where water is ponding
18 in (In this case: superior bottom - mulch - ammended soil - invert of French drain)
16 in
H-design= 1.333 ft H-gravel minus radius ofthe discharge
Oorif-classic" 0.12332 cfs
Odiversion" 0.12455 cfs ^ 1% additional to the Qorifice.
LID Underdrain Outlet
Flowrate to be added
on following sheet to
stage discharge.
Basin #1 Discharge
Discharge vs Elevation Table
Low orifice: 1.5 " Top orifice: 2
Number; 2 Number: 0
Cg-low: 0.61 Cg-low: 0.51
invert elev: 0.50 ft invert elev: 1.50 ft
Middle orifice: 1 " Emergency inlet:
number of orif: 0 Invert: 1.25 ft
Cg-middle: 0.61 Area(SF=2) 4.89 sq ft <— invert elev: 1.00 ft Circumference 7.85 ft
Actual Total Discharge =
Qtot + 0.125
0.125 cfs is added for rate
through LID subdrain
h H/D'low H/D-mid H/D-top Qlow-orif Qlow-weir Qtot-low Qmld-orif Qmid-weir Qtot-med Qtop-orif Qtop-weir Qtot-top Qemerg Qtot
(ft) ---(cfs) (cfs) (cfs) (cfs) (cfs) (cfs) (cfs) (cfs) (cfs) (cfs) (cfs)
0.0 0.00 0.00 0.00 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
0.1 0.00 0.00 0.00 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
0.2 0.00 0.00 0.00 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
0.3 0.00 0.00 0.00 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
0.4 0.00 0.00 0.00 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
0.5 0.00 0.00 0.00 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
0.6 0.80 0.00 0.00 0.023 0.020 0.020 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.020
0.7 1.60 0.00 0.00 0.045 0.056 0.045 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.045
0.8 2.40 0.00 0.00 0.059 0.076 0.059 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.059
0.9 3.20 0.00 0.00 0.070 0.079 0.070 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.070
1.0 4.00 0.00 0.00 0.079 0.130 0.079 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.079
1.1 4.80 1.20 0.00 0.088 0.395 0.088 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.088
1.2 5.60 2.40 0.00 0.096 1.173 0.096 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.096
1.3 6.40 3.60 0.00 0.103 2.936 0.103 0.000 0.000 0.000 0.000 0.000 0.000 0.272 0.375
1.4 7.20 4.80 0.00 0.110 6.361 0.110 0.000 0.000 0.000 0.000 0.000 0.000 1.414 1.524
1.5 8.00 6.00 0.00 0.116 12.361 0.116 0.000 0.000 0.000 0.000 0.000 0.000 3.042 3.158
1.6 8.80 7.20 0.60 0.122 22.129 0.122 0.000 0.000 0.000 0.000 0.000 0.000 5.039 5.161
1.7 9.60 8.40 1.20 0.128 37.163 0.128 0.000 0.000 0.000 0.000 0.000 0.000 7.346 7.474
1.8 10.40 9.60 1.80 0.134 59.307 0.134 0.000 0.000 0.000 0.000 0.000 0.000 9.926 10.060
1.9 11.20 10.80 2.40 0.139 90.784 0.139 0.000 0.000 0.000 0.000 0.000 0.000 12.753 12.892
2.0 12.00 12.00 3.00 0.144 134.229 0.144 0.000 0.000 0.000 0.000 0.000 0.000 15.806 15.950
2.1 12.80 13.20 3.60 0.149 192.729 0.149 0.000 0.000 0.000 0.000 0.000 0.000 19.070 19.219
2.2 13.60 14.40 4.20 0.154 269.850 0.154 0.000 0.000 0.000 0.000 0.000 0.000 22.533 22.687
2.3 14.40 15.60 4.80 0.158 369.679 0.158 0.000 0.000 0.000 0.000 0.000 0.000 24.529 24.587
2.4 15.20 16.80 5.40 0.163 496.854 0.163 0.000 0.000 0.000 0.000 0.000 0.000 25.570 25.833
2.5 16.00 18.00 6.00 0.167 656.603 0.167 0.000 0.000 0.000 0.000 0.000 0.000 26.753 25.930
2.6 16.80 19.20 6.60 0.171 854.773 0.171 0.000 0.000 0.000 0.000 0.000 0.000 27.813 27.985
2.7 17.60 20.40 7.20 0.176 1097.872 0.176 0.000 0.000 0.000 0.000 0.000 0.000 28.825 29.000
2.8 18.40 21.60 7.80 0.180 1393.096 0.180 0.000 0.000 0.000 0.000 0.000 0.000 29.802 29.982
2.9 19.20 22.80 8.40 0.184 1748.371 0.184 0.000 0.000 0.000 0.000 0.000 0.000 30.748 30.932
3.0 20.00 24.00 9.00 0.188 2172.383 0.188 0.000 0.000 0.000 0.000 0.000 0.000 31.557 31.854
3.1 20.80 25.20 9.60 0.191 2674.615 0.191 0.000 0.000 0.000 0.000 0.000 0.000 32.559 32.750
3.2 21.60 26.40 10.20 0.195 3265.380 0.195 0.000 0.000 0.000 0.000 0.000 0.000 33.427 33.622
3.3 22.40 27.60 10.80 0.199 3955.858 0.199 0.000 0.000 0.000 0.000 0.000 0.000 34.274 34.472
3.4 23.20 28.80 11.40 0.202 4758.129 0.202 0.000 0.000 0.000 0.000 0.000 0.000 35.099 35.302
3.5 24.00 30.00 12.00 0.206 5685.209 0.206 0.000 0.000 0.000 0.000 0.000 0.000 35.906 36.112
3.6 24.80 31.20 12.60 0.209 6751,084 0.209 0.000 0.000 0.000 0.000 0.000 0.000 36.696 36.905
3.7 25.60 32.40 13.20 0.213 7970.745 0.213 0.000 0.000 0.000 0.000 0.000 0.000 37.468 37.681
3.8 26.40 33.60 13.80 0.216 9360.223 0.216 0.000 0.000 0.000 0.000 0.000 0.000 38.225 38.442
3.9 27.20 34.80 14.40 0.219 10936.622 0.219 0.000 0.000 0.000 0.000 0.000 0.000 38.968 39.187
4.0 28.00 36.00 15.00 0.223 12718.159 0.223 0.000 0.000 0.000 0.000 0.000 0.000 39.696 39.919
4.1 28.80 37.20 15.60 0.226 14724.192 0.226 0.000 0.000 0.000 0.000 0.000 0.000 40.411 40.637
4.2 29.60 38.40 16.20 0.229 16975.258 0.229 0.000 0.000 0.000 0.000 0.000 0.000 41.114 41.343
4.3 30.40 39.60 16.80 0.232 19493.110 0.232 0.000 0.000 0.000 0.000 0.000 0.000 41.805 42.038
4.4 31.20 40.80 17.40 0.235 22300.747 0.235 0.000 0.000 0.000 0.000 0.000 o.ooo 42.485 42.720
4.5 32.00 42.00 18.00 0.238 25422.454 0.238 0.000 0.000 0.000 0.000 0.000 0.000 43.154 43.393
4.6 32.80 43.20 18.60 0.241 28883.831 0.241 0.000 0.000 0.000 0.000 0.000 0.000 43.813 44.055
4.7 33.60 44.40 19.20 0.244 32711.833 0.244 0.000 0.000 0.000 0.000 0.000 0.000 44.462 44.707
4.8 34.40 45.60 19.80 0.247 36934.803 0.247 0.000 0.000 0.000 0.000 0.000 0.000 45.102 45.349
4.9 35.20 46.80 20.40 0.250 41582.504 0.250 0.000 0.000 0.000 0.000 0.000 0.000 45.733 45.983
5.0 36.00 48.00 21.00 0.253 46686.159 0.253 0.000 0.000 0.000 0.000 0.000 0.000 46.355 46.608
This column calculates both wier and orifice equation
flowrates and displays the minimum value (so long as
the riser rim elevation has been surpassed.
TABATA 10:
STAGE STORAGE
Elevation Depth Area
ft sf
91.3 0 8821
92 0.7 10095
93 1.7 11937
94 2.7 13808
95 3.7 15707
96 4.7 17635
96.3 5 18216
PROPOSED CONDITION: HYDROMODIFICATION ANALYSIS INPUT PARAMETERS: TABATA 10
Subcatchment Basinl
Property Value
Name
X-Coordinate
Y-Coordinate
Description
Tag
Rain Gage
Outlet
Area
width
% Slope
% Imperv
N-Imperv
N-Perv
Dstore-lmperv
Dstore-Perv
^ero-lmperv
Subarea Routing
Percent Routed
Infiltration
Groundwater
Snow Pack
LID Controls
Land Uses
Initial Buildup
Curb Length
i Basinl
fiioizs""'
I5K&444
I Area Tributary to Basin ttl
Oceanside
BR-1
9.36
416
6.1
,56
l^iii
|i035^
l02
^1
125
joUTLEf
[ioo
jGREENjS^MPT
NO
NONE
0
User-assigned name of subcatchment
R:\1203\Hyd\REPORTS\SWMP\1203_SWMP-TABATA10.docx
Subcatchiment BR-1
Property Value
Name
X-Coordinate
Y-Coordinate
Description
Tag
Rain Gage
Outlet
Area
Width
% Slope
Z Imperv
N-Imperv
N'Perv
Dstore-lmperv
Dstore-Perv
SZero-lmperv
Subarea Routing
Percent Routed
Infiltration
Groundwater
Snow Pack
LID Controls
Land U ses
Initial Buildip
Curb Length
jBR-1
14959^350
Oceanside
:Div-1
2
21
10,1
io
0.012
i.i
.02
ll
25
OUTLET "
I IOOl
GREEN_AMPT
NO
1
0
NONE
io
User-assigned name of subcatchment
R:\1203\Hyd\REPORTS\SWMP\1203_SWMP-TABATA lO.docx
Divider Div-1 B
Property Value
Name Div-1
X-Coordinate isTisf"
Y-Coordinate 456i296^
Description
Tag
Inflows NO
Treatment NO
invert EL 0
{Max. Depth 0
1 Initial Depth i
Surcharge Depth 0
Ponded Area 8821
1 Diverted Link Bypass-1
Type CUTOFF
Cutoff Divider
Cutoff Flow .12455
Tabular Divider !
Curve Name
Weir Divider
Min: Flow 0
Max. Depth 0
Coefficient
Cutoff flow value used for a CUTOFF divider (flow units)
R:\1203\Hyd\REPORTS\SWMP\1203_SWMP-TABATA10.docx
Stor^e Unit Stor-1
Property Value
Name
X-Coordinate
Y-Coordinate
Description
Tag
Inflows
Treatment
Invert El.
Max. Depth
Initial Depth
Ponded Area
Evap. Factor
Infiltration
Storage Curve
Functional
Coefficient
Exponent
Constant
Tabular Lurve
Curve Name
iStor-1
4198 830
Basin ttl
NO
NO
iiTi
5
0
8821
1
NO
TABULAR
hooo
ji
10
Basintti
User-assigned name of storage unit
R:\12a3\Hyd\REPORTS\SWMP\1203_SWMP-TABATA lO.docx
Outiet 1
Property Value 1
Name 1 1
Inlet Node
Outlet Node
Stor-1
POC-1
Description
Tag
inietlSffset
Flap Gate
0
NO
Rating Curve TABULAR/DEFTH
Functional Curve j
Coefficient 10.0
Exponent 0.5
Tabuldf Lurve !
1
Curve Name Basintfl Outlet
User-assigned name of outlet
R:\1203\Hyd\REPORTS\SWMP\1203_SWMP-TABATA10.docx
Subcaitchnrtent Bssin2
Property Value
Name
X-Coordinate
Y-Coordinate
Description
Tag
Rain Gage
Outlet
Area
Width
% Slope
% Imperv
N-Imperv
N-Perv
Dstore-lmperv
Distore-Perv
^ero-lmperv
Subarea Routing
Percent Routed
Infiltration
Groundwater
Snow Pack
UD Controls
Land Uses
Initial Buikiup
Curb Length
iBasin2
467.751
3777.964
{Additional area not tributary to basin
lOceanside
[poc-i
'jiig
I'TS^^""^
•2.8
0
0.012
0.035"
l02
.1
25
OUTLET
ilOO
GREENj!*IPT
sNO
0
?0
NONE
:0
User-assigned name of subcatchment
R:\1203\Hyd\REPORTS\SWMP\1203_SWMP-TABATA10.docx
Outfall POC-1
Property Value
Name
X-Coordinate
Y-Coordinate
IPOC-1
T477li52
iB87i66
Description
Tag
lnfk>ws NO
Treatment NO
Invert EL
Tide Gate
0
NO
Type FREE~"'"
Fi;-;ed Outfall j
Fixed Stage |0
Tidal Outfall
Curve Name
Time Serieis Uutfall |
Series Name X
User-assigned name of outfall
R:\1203\Hyd\REPORTS\SWMP\1203_SWMP-TABATA10.docx
UD Control Editor Ijjjjjlj^jjjl'
Control Name:
LID Type:
Process Layers:
Bio-Retention Cell
Surface Soil I Storage | Underdrain
Storage Depth
(in. or mm)
Vegetation Volume
Fraction
Surface Roughness
[Mannings n)
Surface Slope
(percent)
0.1
0.1
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R:\1203\Hyd\REPORTS\SWMP\1203_SWMP-TABATA10.docx
UD Control Editor
Control Name:
LID Type:
Process Layers:
Bio-Retention Cell
Soil $t(3rage! I Und^rdram
Thickness
(in. or mm)
Porosity
(volume fraction)
Field Capacity
(volume fraction)
Wilting Point
(volume fraction)
Conductivity
(in/hr or mm/hr)
Conductivity Slope
Suction Head
(in. or mm)
18
0.25
0.05
5
1.5
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LID Type:
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Surface | Soil| Storage Underdrain
18
0.025
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(in. or mm)
Void Ratio
(Voids / Solids)
Conductivity
(in/hr or mm/hr)
Clogging Factor
Note: use a Conductivity of 0 if the LID
unit has an impermeable bottom.
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R:\1203\Hyd\REPORTS\SWMP\1203_SWIV1P-TABATA10.docx
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LID Type:
Process Layers:
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Surface Soil Storage Underdrain
Drain Coefficient
(in/hr or mm/hr)
Drain Exponent
Drain Offset Height
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0.1510
0.5
Note: use a Drain Coefficient of 0 if the
LID unit has no underdrain.
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R;\1203\Hyd\REPORTS\SWMP\1203_SWMP-TABATA lO.docx
TABATA 10 BASIN : STAGE DISCHARGE
Rating Curve Editor
Curve Name
Basintti Outlet
Description
Head
(ft)
Outflow
(CFS) •
1 0.0 0.000
2 0.1 iooo
3 0.2 iooo
4 0.3 10.000
5 0.4 0.000
6 0.5 iooo
7 0.6 io2i ;
8 0.7 i045 '
9 0.8 0.059
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o
O
flating Cuiwe Basin#1 Outlet
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TABATA 10 BASIN : STAGE STORAGE
Stor^e Curve Editor
Curve Name
Basintti
Description
Basin ttl
Depth
(ft)
Area
mi
1 0 8821
2 .7 10095
3 1.7 11937
4 2.7 13808 1
5 3.7 15707
6 4.7 17635
7 5 18216
8 \
9
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R:\12a3\Hyd\REPORTS\SWMP\1203_SWMP-TABATA10.docx
6 - SWMM Modeling Results
R:\1203\Hyd\REPORTS\SWIVIP\1203_SWIVlP-TABATA10.docx
List of Peak events and Determination of P2 and PIO (Pre-Development)
T Cunnane Weibull Period of Return
10 7.39 7.65 Peaks Date Position Weibull Cunnane
9 7.22 7.30 3.43 3/16/1954 57 1.02 1.01
8 7.04 7.10 3.45 2/11/1959 56 1.04 1,03
7 6.91 6.93 3.47 12/2/1961 55 1.05 1.05
6 6.37 6.50 3.48 1/21/1964 54 1.07 1,07
5 6.24 6.24 3.53 11/16/1965 53 1.09 1,09
4 6.04 6.04 3.54 11/17/1972 52 1.12 1,11
3 5.30 5.31 3.55 3/20/1973 51 1.14 1.13
2 4.69 4.69 3.56 1/6/1977 50 1.16 1.15
3.69 1/14/1978 49 1,18 1.18
3.77 3/11/1978 48 1,21 1.20
Note: 3.77 11/25/1985 47 1.23 1,23
Cunnane Is the preferred 3.8 1/18/1952 46 1.26 1.25
method by the HMP permit. 3.83 12/18/1967 45 1.29 1,28
3.87 1/14/1969 44 1.32 1.31
3.91 2/6/1969 43 1.35 1.34
4.03 2/17/1971 42 1.38 1.38
4.04 2/8/1976 41 1.41 1.41
4.05 12/31/1976 40 1.45 1.44
4.09 5/8/1977 39 1.49 1,48
4.1 1/6/1979 38 1.53 1.52
4.17 3/1/1981 37 1.57 1.56
4.28 3/17/1982 36 1.61 1.61
4.3 3/24/1983 35 1.66 1,65
4.37 11/25/1983 34 1.71 1.70
4.38 1/18/1993 33 1.76 1.75
4.42 3/11/1995 32 1.81 1.81
4.48 12/28/2004 31 1.87 1,87
4.61 2/21/2005 30 1.93 1,93
4.69 2/21/2005 29 2.00 2,00
4.74 2/3/1958 28 2.07 2,07
4.98 3/6/1975 27 2.15 2,15
4.99 2/25/1981 26 2.23 2,23
5.03 3/1/1983 25 2.32 2.33
5.03 11/17/1986 24 2.42 2.42
5.22 12/4/1987 23 2.52 2,53
5.23 4/21/1988 22 2,64 2,65
5.23 1/31/1993 21 2.76 2,78
5.24 2/14/1995 20 2,90 2.92
5.35 12/23/1995 19 3,05 3.08
5.79 1/12/1960 18 3,22 3.25
5.92 3/8/1968 17 3,41 3.45
6.01 12/4/1974 16 3.63 3.67
6,03 3/16/1986 15 3.87 3.92
6,06 11/5/1987 14 4.14 4.21
6.1 1/10/1955 13 4.46 4.54
6.24 1/10/1978 12 4.83 4.93
6.25 1/25/1995 11 5.27 5.40
6.34 10/27/2004 10 5.80 5.96
6.87 11/21/1967 9 6.44 6.65
6.96 2/28/1970 8 7.25 7.53
7.16 11/16/1972 7 8.29 8.67
7.43 1/31/1979 6 9.67 10.21
8.73 2/24/1998 5 11.60 12.43
9.04 12/29/2004 4 14,50 15,89
9.57 2/20/1980 3 19.33 22.00
9.74 3/7/1952 2 29.00 35.75
10.67 12/10/1965 1 58.00 95,33
List of Peak events and Determination of P2 and PIO (Post-Development)
T Cunnane Weibull Period of Return
10 6.56 6.76 Peaks Date Position Weibull Cunnane
9 6.49 6.52 2.31 1/13/1952 57 1,02 1,01
8 6.34 6.40 2.35 1/18/1952 56 1,04 1.03
7 5.82 6.03 2.36 1/18/1952 55 1,05 1.05
6 5.47 5.49 2.41 12/20/1952 54 1.07 1.07
5 5.36 5.37 2,42 1/10/1955 53 1.09 1.09
4 4.55 4.55 2.43 1/7/1957 52 1.12 1.11
3 4.46 4.46 2,51 1/20/1962 51 1.14 1,13
2 2.99 2.99 2.52 4/8/1965 50 1.16 1.15
2.57 3/22/1954 49 1.18 1,18
2.59 12/5/1957 48 1.21 1.20
Note: 2.6 1/12/1960 47 1.23 1.23
Cunnane is the preferred 2.61 12/2/1961 46 1.26 1,25
method bythe HMP permit. 2.62 11/20/1963 45 1.29 1,28
2.63 12/5/1966 44 1,32 1,31
2.63 1/14/1969 43 1,35 1.34
2.67 12/21/2002 42 1,38 1.38
2.69 2/14/2003 41 1.41 1,41
2.7 2/22/2004 40 1,45 1.44
2.74 3/7/1952 39 1.49 1,48
2,75 3/16/1958 38 1.53 1,52
2.75 3/1/1981 37 1.57 1.56
2.86 3/17/1982 36 1.61 1.61
2,89 2/2/1983 35 1.66 1.65
2,93 3/1/1983 34 1.71 1.70
2,93 11/25/1985 33 1.76 1.75
2,95 3/1/1991 32 1.81 1.81
2.96 2/19/1993 31 1,87 1.87
2.96 3/11/1995 30 1,93 1,93
2.99 3/11/1995 29 2,00 2,00
3.02 2/3/1998 28 2,07 2.07
3.16 2/8/1998 27 2.15 2,15
3.27 2/12/2003 26 2.23 2.23
3.29 3/5/2005 25 2.32 2.33
3.32 12/30/1951 24 2.42 2.42
3.54 3/16/1952 23 2.52 2,53
3.63 3/16/1986 22 2.64 2.65
3.79 1/14/1990 21 2,76 2.78
4,45 1/15/1993 20 2,90 2.92
4.46 1/25/1995 19 3,05 3,08
4.47 1/25/1995 18 3,22 3,25
4.51 11/22/1996 17 3.41 3.45
4.51 10/27/2004 16 3.63 3,67
4,55 12/29/2004 15 3.87 3.92
4,55 1/3/2005 14 4.14 4.21
4.8 3/6/1975 13 4.46 4.54
5.35 1/10/1978 12 4.83 4.93
5.4 1/14/1978 11 5,27 5.40
5.47 1/11/2001 10 5.80 5.96
5.53 3/2/1983 9 6.44 6,65
6.26 11/5/1987 8 7.25 7.53
6.46 11/21/1967 7 8.29 8,67
6,58 2/28/1970 6 9.67 10.21
7.65 11/16/1972 5 11.60 12,43
8,5 1/31/1979 4 14.50 15,89
9.41 1/4/1995 3 19.33 22,00
9.67 2/21/2005 2 29.00 35,75
10.59 12/10/1965 1 58.00 95,33
Flow Duration Curve Data for Tabata 10
Q2 =
Q10 =
Step =
Count:
4.69 cfs
7.39 cfs
0.0699 cfs
499678 hours
57.00 years
Fraction Q2= 10 %
Interval
Existing Condition Detention Basin Optimized Pass or
Fail? Interval Q(cfs) Hours > Q %time Hours>Q %time Post/Pre
Pass or
Fail?
1 0.469 934 1.87E-01 817 1.64E-01 87% Pass
2 0.539 859 1.72E-01 713 1.43E-01 83% Pass
3 0.609 791 1.58E-01 635 1.27E-01 80% Pass
4 0.679 718 1.44E-01 578 1.16E-01 81% Pass
5 0.749 657 1.31E-01 539 1.08E-01 82% Pass
6 0.819 602 1.20E-01 494 9.89E-02 82% Pass
7 0.889 554 l.llE-01 438 8.77E-02 79% Pass
8 0.959 521 1.04E-01 401 8.03E-02 77% Pass
9 1.028 483 9.67E-02 370 7.40E-02 77% Pass
10 1.098 458 9.17E-02 343 6.86E-02 75% Pass
11 1.168 434 8.69E-02 325 6.50E-02 75% Pass
12 1.238 409 8.19E-02 301 6.02E-02 74% Pass
13 1.308 383 7.66E-02 277 5.54E-02 72% Pass
14 1.378 349 6.98E-02 252 5.04E-02 72% Pass
15 1.448 329 6.58E-02 229 4.58E-02 70% Pass
16 1.518 309 6.18E-02 216 4.32E-02 70% Pass
17 1.588 283 5.66E-02 201 4.02E-02 71% Pass
18 1.658 256 5.12E-02 188 3.76E-02 73% Pass
19 1.728 241 4.82E-02 174 3.48E-02 72% Pass
20 1.798 228 4.56E-02 162 3.24E-02 71% Pass
21 1.868 217 4.34E-02 153 3.06E-02 71% Pass
22 1.938 211 4.22E-02 143 2.86E-02 68% Pass
23 2.008 202 4.04E-02 134 2.68E-02 66% Pass
24 2.078 190 3.80E-02 126 2.52E-02 66% Pass
25 2.147 178 3.56E-02 118 2.36E-02 66% Pass
26 2.217 168 3.36E-02 112 2.24E-02 67% Pass
27 2.287 156 3.12E-02 105 2.10E-02 67% Pass
28 2.357 142 2.84E-02 96 1.92E-02 68% Pass
29 2.427 133 2.66E-02 92 1.84E-02 69% Pass
30 2.497 127 2.54E-02 87 1.74E-02 69% Pass
31 2.567 121 2.42E-02 79 1.58E-02 65% Pass
32 2.637 114 2.28E-02 72 1.44E-02 63% Pass
33 2.707 110 2.20E-02 65 1.30E-02 59% Pass
34 2.777 101 2.02E-02 60 1.20E-02 59% Pass
35 2.847 99 1.98E-02 59 1.18E-02 60% Pass
36 2.917 94 1.88E-02 56 1.12E-02 60% Pass
Interval
Existing Cond tion Detention Basin Optimized Pass or
Fail? Interval Q(cfs) Hours > Q %time Hours>Q %time Post/Pre
Pass or
Fail?
37 2.987 91 1.82E-02 48 9.61E-03 53% Pass
38 3.057 88 1.76E-02 42 8.41E-03 48% Pass
39 3.127 83 1.66E-02 41 8.21E-03 49% Pass
40 3.196 79 1.58E-02 39 7.81E-03 49% Pass
41 3.266 74 1.48E-02 37 7.40E-03 50% Pass
42 3.336 66 1.32E-02 32 6.40E-03 48% Pass
43 3.406 65 1.30E-02 32 6.40E-03 49% Pass
44 3.476 61 1.22E-02 32 6.40E-03 52% Pass
45 3.546 58 1.16E-02 29 5.80E-03 50% Pass
46 3.616 56 1.12E-02 29 5.80E-03 52% Pass
47 3.686 56 1.12E-02 27 5.40E-03 48% Pass
48 3.756 54 1.08E-02 27 5.40E-03 50% Pass
49 3.826 51 1.02E-02 26 5.20E-03 51% Pass
50 3.896 49 9.81E-03 25 5.00E-03 51% Pass
51 3.966 48 9.61E-03 25 5.00E-03 52% Pass
52 4.036 46 9.21E-03 24 4.80E-03 52% Pass
53 4.106 41 8.21E-03 24 4.80E-03 59% Pass
54 4.176 40 8.01E-03 24 4.80E-03 60% Pass
55 4.246 40 8.01E-03 24 4.80E-03 60% Pass
56 4.315 38 7.60E-03 24 4.80E-03 63% Pass
57 4.385 36 7.20E-03 23 4.60E-03 64% Pass
58 4.455 35 7.00E-03 22 4.40E-03 63% Pass
59 4.525 34 6.80E-03 18 3.60E-03 53% Pass
60 4.595 34 6.80E-03 16 3.20E-03 47% Pass
61 4.665 33 6.60E-03 16 3.20E-03 48% Pass
62 4.735 32 6.40E-03 15 3.00E-03 47% Pass
63 4.805 31 6.20E-03 14 2.80E-03 45% Pass
64 4.875 31 6.20E-03 13 2.60E-03 42% Pass
65 4.945 31 6.20E-03 13 2.60E-03 42% Pass
66 5.015 29 5.80E-03 13 2.60E-03 45% Pass
67 5.085 27 5.40E-03 13 2.60E-03 48% Pass
68 5.155 27 5.40E-03 13 2.60E-03 48% Pass
69 5.225 25 5.00E-03 13 2.60E-03 52% Pass
70 5.295 22 4.40E-03 13 2.60E-03 59% Pass
71 5.364 21 4.20E-03 12 2.40E-03 57% Pass
72 5.434 21 4.20E-03 11 2.20E-03 52% Pass
73 5.504 21 4.20E-03 10 2.00E-03 48% Pass
74 5.574 21 4.20E-03 9 1.80E-03 43% Pass
75 5.644 20 4.00E-03 9 1.80E-03 45% Pass
76 5.714 20 4.00E-03 9 1.80E-03 45% Pass
77 5.784 20 4.00E-03 9 1.80E-03 45% Pass
78 5.854 19 3.80E-03 9 1.80E-03 47% Pass
79 5.924 18 3.60E-03 9 1.80E-03 50% Pass
80 5.994 18 3.60E-03 9 1.80E-03 50% Pass
81 6.064 15 3.00E-03 9 1.80E-03 60% Pass
Interval
Existing Condition Detention Basin Optimized Pass or
Fail? Interval Q(cfs) Hours > Q %time Hours>Q %time Post/Pre
Pass or
Fail?
82 6.134 14 2.80E-03 9 1.80E-03 64% Pass
83 6.204 14 2.80E-03 9 1.80E-03 64% Pass
84 6.274 12 2.40E-03 8 1.60E-03 67% Pass
85 6.344 10 2.00E-03 8 1.60E-03 80% Pass
86 6.414 9 1.80E-03 8 1.60E-03 89% Pass
87 6.483 9 1.80E-03 7 1.40E-03 78% Pass
88 6.553 9 1.80E-03 7 1.40E-03 78% Pass
89 6.623 9 1.80E-03 6 1.20E-03 67% Pass
90 6.693 9 1.80E-03 6 1.20E-03 67% Pass
91 6.763 9 1.80E-03 6 1.20E-03 67% Pass
92 6.833 9 1.80E-03 6 1.20E-03 67% Pass
93 6.903 8 1.60E-03 6 1.20E-03 75% Pass
94 6.973 7 1.40E-03 6 1.20E-03 86% Pass
95 7.043 7 1.40E-03 5 l.OOE-03 71% Pass
96 7.113 7 1.40E-03 5 l.OOE-03 71% Pass
97 7.183 6 1.20E-03 5 l.OOE-03 83% Pass
98 7.253 6 1.20E-03 5 l.OOE-03 83% Pass
99 7.323 6 1.20E-03 5 l.OOE-03 83% Pass
100 7.393 6 1.20E-03 5 l.OOE-03 83% Pass
Peak Flows calculated with Cunnane Plotting Position
Return Period
Pre-dev. Q Post-Dev. Q Reduction
10 7.393 6.563 0.829
9 7.218 6.486 0.732
8 7.043 6.343 0.700
7 6.906 5.821 1.085
6 6.372 5.474 0.898
5 6.241 5.357 0.884
4 6.039 4.550 1.489
3 5.297 4.455 0.842
2 4.690 2.990 1.700
Tabata Flow Duration Curve
0
0.05%
Existing
Proposed
Qx
5.00%
Percentage of time exceeded (%)
Tabata Flow Duration Curve
a
0.1%
Percentage of time exceeded (%)