HomeMy WebLinkAboutCT 16-09; 800 GRAND AVENUE; PRIORITY DEVELOPMENT(PDP) STORM WATER QUALITY MANAGEMENT PLAN(SWQMP); 2018-05-01CITY OF CARLSBAD
PRIORITY DEVELOPMENT PROJECT (PDP)
STORM WATER QUALITY MANAGEMENT PLAN (SWQMP)
FOR
800 GRAND AVENUE
CT 16-09
DWG 509-IA/GR2017-0072
ENGINEER OF WORK:
11,,--A1,/ 6 -1 ~g
RONALD HOLLOWAY RCE 2 271 EXP 3-31-2019 DATE
PREPARED FOR:
McKELLAR-McGOWAN
888 PROSPECT STREET, #330
LA JOLLA, CA 92037 No. 29271
858-342-9725
PREPARED BY:
bhA. Inc
land planning, civil engineering, surveying
5115 AVENIDA ENCINAS, SUITE L
CARLSBAD, CA 92008-4387
(760) 931-8700
DATE:
MAY 1, 2018
W.O. 1026-1383-400
RECEIVED
JUN 04 2018
LAND DEVELOPMENT c'
ENGINEERING
LL
TABLE OF CONTENTS
I Certification Page
Project Vicinity Map
I FORM E-34 Storm Water Standard Questionnaire
Site Information
FORM E-36 Standard Project Requirement Checklist
I Summary of PDP Structural BMPs
Attachment 1: Backup for PDP Pollutant Control BMPs
Attachment 1 a: DMA Exhibit
I Attachment 1 b: Tabular Summary of DMAs and Design Capture Volume Calculations
Attachment 1 c: Harvest and Use Feasibility Screening (when applicable)
Attachment id: Categorization of Infiltration Feasibility Condition (when applicable)
I
Attachment 1 e: Pollutant Control BMP Design Worksheets / Calculations Attachment 2: Structural BMP Maintenance Thresholds and Actions
Attachment 3: Single Sheet BMP (SSBMP) Exhibit
Attachment 4: Geotechnical Reference
I
1 2
CERTIFICATION PAGE
I Project Name: 800 Grand Avenue
Project ID: CDP 16-25
I I hereby declare that I am the Engineer in Responsible Charge of design of storm water BMPs for
this project, and that I have exercised responsible charge over the design of the project as defined
in Section 6703 of the Business and Professions Code, and that the design is consistent with the
I requirements of the BMP Design Manual, which is based on the requirements of SDRWQCB
Order No. R9-2013-0001 (MS4 Permit) or the current Order.
I I have read and understand that the City Engineer has adopted minimum requirements for
managing urban runoff, including storm water, from land development activities, as described in
the BMP Design Manual. I certify that this SWQMP has been completed to the best of my ability
I and accurately reflects the project being proposed and the applicable source control and site
design BMPs proposed to minimize the potentially negative impacts of this project's land
development activities on water quality. I understand and acknowledge that the plan check review
of this SWQMP by the City Engineer is confined to a review and does not relieve me, as the
I Engineer in Responsible Charge of design of storm water BMPs for this project, of my
responsibilities for project design.
iL__\'JLi7 R.C.E. 29271 Exp. 3/3
Engineer of Work's Sigature, PE Number & Expiration Date
I Ronald Hollow
Print Name
I bhA, Inc
land planning, civil engineering, surveying
May 1. 2018
Date
3
PROJECT VICINITY MAP
VICINInlY MAP
4
STORM WATER-STANDARDS 1O (1LSY1S lcl,r QUESTIONNAIRE Cit\ Oi Land Development Engineering
aT 1635 Faraday Avenue 10 Cl E-34 1760) 602-2750
wvvw carlsbadca gov
I INSTRUCTIONS:
To address post development pollutants that may be generated from development projects, the city requires that new
I development and significant redevelopment priority projects incorporate Permanent Storm Water Best Management
Practices (BMP) into the project design per Carlsbad BMP Design Manual (BMP Manual) To view the BMP Manual
refer totijeEngineering Standards (Volume 5).
This questionnaire must be completed by the applicant in adv ance,-of submitting for a development application
(subdivision discretionary permits and/or construction permits) The results of the questionnaire determine thetevel of
I storm water standards that must be applied to a proposed development .-Or redevelopment project Dapending on the
outcome your project will either be subject to STANDARD PROJECT requirements or be subject to PRIORITY
DEVELOPMENT PROJECT (PD P) req use ments
I Your responses to the questionnaire represent an initial assessment of the proposed project conditions and impacts City
staff has responsibility for making thefinal 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 asessed by you this will result in the return of the development application as incomplete In this case please
I m11 ake the chanestothe.questionnajreand 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 completed and sigp•èd questionnaire must be submitted with each development project application.Only one
I completed and signed questionnaire is required when multiple development applications for the same project are
submitted concurrently.
PROJECT INFORMATION
PRQLETNAME: 800 Grand Avenue PROJECT ID CT 1 B-US/PP 16-16
ADDRESS 800 Grand Avenue, Carlsbad C4 92006 APN 203 202 16
The project is (check one 0 New Development U Redevelopment
The total proposed disturbed area is 98 fi2 (_9_) acres
Thetdtal proposed nwlfcreatedbnd/orreplated'irirvioiisareais:9°2 ft2 (.9._jacre5
If your project is covered by on approved SWOMP as part of 'a larger development project provide the project ID and the
StNQMP#of the larger development project
Project ID SWQMP
Then, go to StOpi and follow the instructirtit:l. When, ..cmptetesign the :.form at the end and submit this. With your
application to the city.
E-34 Page 1 o14 REV02II6
STEP I
TO BE COMPLETED FOR ALL PROJECTS
To determine if your project is development project',please answer the following question:
YE8 NO
Is: yburproject LIMITED TOroUtitie mairiteflarieI acti'Qity and/or rep r/improv.ements:td.:an existing building. o or structure that do not alter the size (See Section 1.3 of the BMP Design Manual for ,guidai)?.
If you answered yes to the above question provide justification below then go to Step 5 mark the third box stating my
präject is not. a 'development project' and not subject to the requirements of the BMP manual and complete applicant
information.
jListifiOatiordisdussiorr (e.g. the project inclüdës only interior remodels, within an existing building):
If you answered "no"to the above question, the project is a 'development project', go to Step 2;
STEP 2
TO BE COMPLETED FOR ALL DEVELOPMENT PROJECTS
To determine if your project is exempt from PDP requirements pursuant to. MS4 Permit Provision E.3.b.(), please answer
the following questions:
Is your project LIM ITED to one or more of the following
YES NO
1. Constructing new or retrofitting paved sidewalks, bicycle lanes or trails that meet the following criteria:
Designed and constructed to direct storm water runoff to adjacent vegetated areas; .or other non-
erodible permeable areas; 11 El Designed and constructed to be hydraulically disconnected from paved streets or roads.;
Designed and constructed with permeable pavements or surfaces in accordance with USEPA
Green Streets guidance? -
2 Retrofitting or redeveloping existing paved alleys streets or roads that are designed and constructed in 11 E accordance with the USEPA Green Streets guidance?
3 Ground Mounted Solar Array that meets the criteria provided in section 1.4.2 of the BMP manual' 11 El
If you answered yes to one or more of the above questions provide discussion/justification below then go to Step 5 mark
the second box stating "my project is EXEMPT from PDP ..." and complete applicant information.
Discussion to jUstify, exemption (e.g. the project redeveloping existing road designed and constructedin accordance with
the USEPA Green Street guidance):.
If you ánsweréd 'no" to the above questions, your project is hot.exeipt from PDP, go to Step 3.
E44 Page 2of4 REV 02/16
OW STEP 3 - V
TO BE COMPLETED FOR ALL NEW OR REDEVELOPMENT PROJECTS
To determine if your project is a PDP, please answerthefollowing questions (MS4 Permit Provision E:3.•6 1 '
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 industnal residential mixed use [1 j]
and public development projects on public or private land,- - 2 Is your project a redevelopment project creating and/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 impervious surface? This includes commercial industrial residential mixed use and public
development projects on public or private land:
Is your project a new: or redevelopment projectthat creates and/or replaces 5,000 square..feetor more
of impervious surface collectively over the entire project site and supports a restaurant? A restaurant is
a facility that sells prepared foods and dnnks for consumption including stationary, lunch counters and fl
refreshment stands selling prepared foods and drinks for immediate consumption (Stándárd Industrial
Classification (SIC) code 5812). -
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 U
development project includes development on any natural slope that is twenty-five percent or greater.
ls.your project a new or redevelopment project that creates and/or replaces 5,000 square feet or more
of impervious surface collectively over the entire project site and supports a parking lot? ,A parking lot is El Q a land area or facility for the temporary parking or storage of motor vehicles used personally for
business or for commerce.
Isyour project a new or redevelopment project.that creates and/or replaces 5000, square feet or more
of impervious surface collectively over the entire project site and supports a street, road, highway
d freeway or riveway? A street, road, highway, freeway or driveway is any paved impervious surface
used for the transportation of automobiles, trucks, motorcycles, and other vehicles. -
Is your project a new or redevelopment project that creates: and/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 overland a distance of 0 0. 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 commingled with flows from adjacent lands).
lsyour project.a new development or redevelopment project that creates and/or replaces .5,000 square
feet or 'more' of impervious surface that supports an automotive repair shop? An automotive repair
shop is a facility that is categorized in anyone of the following Standard Industrial Classification (SIC)
cedes: 5013, 5014, 5541, 7532-7534, or 7536' 7539.
ls.your project a new development or redevelopment project that creates and/or replaces 5,000, square
feet or more of impervious area that supports a retail gasoline outlet (RGO)2 This caterjory includes
RGO's that meet the following criteria: (a) 5,000 square feet or more or (b) a projectAverage Daily
Traffic (AD1) of 100 or more vehicles per day. - lsyour project a new or, redevelopment project that results in the disturbance of one or rriore.ac.rtis of land
and are.expected to generate pollutants post construction?
11., ls.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%? (CMC 0
21.203.040)
If you answered "yes" to one or more of the above questions, your project is a PDP. If your project is a redevelopment
project, go to step 4. If your project is a new project, go to step 5, check the first box stating "My project is a PDP
and complete applicant information.
If you answered "no" to all of the above questions, your project is a 'STANDARD PROJECT.' Go to step 5, check the
second box stating "My project is a 'STANDARD PROJECT'.....and complete applicant information.
E-34 Page3of4 REV 02116
STEP 4
TO BE COMPLETED FOR REDEVELOPMENT PROJECTS THAT ARE PRIORITY DEVELOPMENT PROJECTS (POP)
ONLY
Complete the questions below regarding your redevelopment project (M54 Permit Pruvsion E.3.o.(2)):
YES NO
Does the redevelopment project result in the creation or replacement of impervious surface in an amount - of less than 5004 of the surface area of the previously existing development? Complete the percent
impervious calculation below.-
Existing impervious area (A).= sq. ft. U El
Total proposed newly created or replaced impervious area (B) = sq. ft.
Percent impervious area created or replaced (BIA)*1 00 =
If you answered yes, the structural BMPs required for POP apply only to the creation or replacement of impervious
surface and not the entire development. Go to step 5, check the first box stating My project is a PDP ......and, complete applicant information.
If you answered the structural BMP's required for PDP apply to the entire development. Go to step 5, check the
check the first box stating My project is a PDP. . and complete applicant information. - -- STEP 5
CHECK THE APPROPRIATE BOX AND COMPLETE APPLICANT INFORMATION
M" project is a PDP and must comply with POP stormwater requirements of the BMP Manual. I unJLr and I must
prepare a Storm Water Quality Management Plan (SWQMP) for submittal at time of application.
o My project Is a 'STANDARD PROJECT' OR EXEMPT from POP and must only comply with STANDARD PROJECT'
stormwater requirements of the BMP Manual. As part of these requirements, I will submit a Standard Project
Requirement Checklist Form E-36 and incorporate low impact development strategies throughout my project.
Note: For projects that are close to meeting the POP threshold, staff may require detailed impervious area calculations
and exhibits to verify If 'STANDARD PROJECT' stormwater requirements apply.
[]My Project is NOT a 'development project' and is not subject to the requirements of the BMP Manual.
Applicant Information and Signature Box
Applicant Na 4vi_C m Applicant Title:
Applicant sign Date: /') /'4 .4.
cl Co
- --- Biological Significance by the Stale Waler Resources Controt Board (Water. QualIty-Control Plan for the San Diego Basin (1994) and smendments) water bodies designated a,ith the RARE beneficrat use by the State Water. Resources Control Board (Water Quality Control Plan for the San Diego Basin (1994) and
amendments) areas designated as preserves or their equivalent under the Multi Species Conservation Program within the Cities and County Si San Diego Habitat
Management Plan; and any otherequivaienrt-envirànmentatiy sensitive areas which have been identified by the City.
Tl,ik Ft6v I t rt,,i,,
City Concurrence:
YES NO
By:
Date:
Project ID:
E4 Page -4 of 4. REV 02/16
8
SITE INFORMATION CHECKLIST
Project Summary Information
Project Name 800 Grand Avenue
Project ID CT 16-09
Project Address 800 Grand Avenue, Carlsbad, CA 92008
Assessor's Parcel Number(s) (APN(s)) 203-202-18
Project Watershed (Hydrologic Unit) 9 Carlsbad 904
Project Hydrologic Unit Hydrologic Area Select One:
LI Loma Alta 904.1
LI Buena Vista Creek 904.2
Agua Hedionda 904.3
LI Encinas 904.4
LI San Marcos 904.5
LI Escondido Creek 904.6
Parcel Area
(total area of Assessor's Parcel(s) 0.96 Acres (_41 ,906 Square Feet)
associated with the project)
Area to be disturbed by the project
(Project Area) 1.07 Acres ( 46,398 Square Feet)
Project Proposed Impervious Area
(subsetofProjectArea) 0.90 Acres (_39,022 Square Feet)
Project Proposed Pervious Area
(subset of Project Area) ,376 Square Feet) 0.17 Acres (--7
Note: Proposed Impervious Area + Proposed Pervious Area = Area to be Disturbed by the
Project.
This may be less than the Parcel Area.
I
Description of Existing Site Condition and Drainage Patterns
Current Status of the Site (select all that apply):
Existing development
Previously graded but not built out
Agricultural or other non-impervious use
LI Vacant, undeveloped/natural
Description / Additional Information:
The existing site is approximately 0.96 acres and has been previously graded. The site
currently includes three commercial buildings and a parking lot.
Existing Land Cover Includes (select all that apply):
LI Vegetative Cover
Non-Vegetated Pervious Areas
Impervious Areas
Description / Additional Information:
The site is currently an impervious parking lot.
Underlying Soil belongs to Hydrologic Soil Group (select all that apply):
LI NRCS Type A
NRCS Type B
LI NRCS Type C
LI NRCS Type D
The on-site soil classification is Type-B from USGS Web Soil Survey.
Approximate Depth to Groundwater (GW):
LI GW Depth <5 feet
LI 5 feet < GW Depth < 10 feet
LI 10 feet < GW Depth <20 feet
GW Depth > 20 feet
10
Existing Natural Hydrologic Features (select all that apply):
LI Watercourses
LI Seeps
LII Springs
LI Wetlands
None
Description I Additional Information:
There are no existing natural hydrologic features.
11
Description of Existing Site Topography and Drainage [How is storm water runoff conveyed
from the site? At a minimum, this description should answer (1) whether existing drainage
conveyance is natural or urban; (2) describe existing constructed storm water conveyance
systems, if applicable; and (3) is runoff from offsite conveyed through the site? if so, describe]:
Storm flows affecting the site are limited to the rainfall that lands directly on the property. Surface
runoff sheet flows south across the impervious parking lot to Grand Avenue. Runoff that drains
to Grand Avenue will be conveyed southwest via existing curb and gutter to the storm drain
system on Grand Avenue. Approximately 100% of the existing site is impervious.
The on-site soil classification is Type B from USGS Web Soil Survey.
Description of Proposed Site Development and Drainage Patterns
Project Description / Proposed Land Use and/or Activities:
The project proposes the development of a multi-unit apartment complex with underground
parking. Proposed drainage improvements consist of two (2) biofiltration BMPs to provide
stormwater treatment and maintain the pre-developed runoff characteristics. The project drains
to one (1) Point of Compliance (POC) located to the southwest corner of the project site.
List/describe proposed impervious features of the project (e.g., buildings, roadways, parking
lots, courtyards, athletic courts, other impervious features):
The proposed impervious features of the project include the multi-unit apartment complex and
concrete sidewalks along the perimeter of the project site.
List/describe proposed pervious features of the project (e.g., landscape areas):
The proposed pervious features of the project include landscape areas surrounding the
apartment building and the proposed biofiltration basins in the front of the property.
Does the project include grading and changes to site topography?
EYes
0 N
Description / Additional Information:
Project grading will occur on approximately 1.07 acres of the project. Storm water flows from
impervious roof area will be conveyed via roof drains to the proposed biofiltration basins along
the southerly property boundary. The biofiltration basins will outlet via storm drains which will
discharge at proposed curb outlets on Grand Avenue. The storm drain system will require
excavation and installation of underground storm drains. Post-development site flow will mimic
existing drainage conditions, and will discharge from the site at below historical flow rates. See
the "Drainage Study for 800 Grand Avenue" by BHA, Inc. dated September 2017 for post-
development drainage calculations. Impervious surfaces have been minimized where feasible.
1 13
Does the project include changes to site drainage (e.g., installation of new storm water
conveyance systems)?
EYes
LNo
Description / Additional Information:
Storm water runoff from the proposed project site is routed to a single POC located at the
southwest of the project site. The proposed drainage pattern will be similar to the existing
drainage pattern with some modifications to incorporate Best Management Practices (BMPs) into
the project design to mimic the impacts on storm water runoff and quality. Approximately 87% of
the developed site will be impervious.
Runoff from the developed project site is drained to two (2) onsite biofiltration BMPs (Water
Quality-BMPs or WQ-BMPs) for water quality purposes (the project is not subject to
hydromodification requirements). Once flows are routed via the proposed WQ-BMPs, all flows
are then conveyed via storm drain to the aforementioned POC.
DMA-1A and DMA-113 encompasses runoff from the proposed building. Roof drains will collect
runoff from the proposed building and discharge into the proposed biofiltration basins, BMP-1A
and BMP-1B, located between the southerly property line and the proposed building. The
biofiltration basins will provide stormwater treatment and flow detention. Treated water will
discharge via storm drain pipes to proposed curb outlets onto Grand Avenue.
Runoff from the concrete sidewalk area will intercepted by a private storm drain system and
conveyed to underground vaults located underneath the garage. The underground vaults will be
sized as a cistern to store the volume from a 100-year storm event. Trench drains within the
underground garage will also collect miscellaneous storm water runoff and will convey flow to an
underground vault. Sump pumps located in a pump room will pump storm water runoff to the
biofiltration basins for treatment based at a maximum of 0.03 cubic feet per second (13.5 gallons
per minute). For stormwater runoff greater than a 100-year storm event, a backup pump will start
automatically to empty the underground vault.
Small landscaped areas in the southern portion of the project will gravity flow towards Grand
Avenue. The landscape areas will be designed with native and/or drought tolerant species. These
areas are considered Self-mitigating DMAs per Section 5.2.1 of the BMP Design Manual and
illustrated on the DMA Exhibit.
The concrete driveway and sidewalk areas, within the street right of way, that gravity flow towards
Grand Avenue are considered De Minimis DMAs per Section 5.2.1 of the BMP Design Manual.
These impervious areas are less than 2 percent of the total added or replaced impervious surface
of the project and are not considered to be a significant contributor of pollutants.
See Attachment 1 b for qualifying site design BMP calculations.
14
Portions of the existing sidewalk within the street right of way will be replaced with landscaped
areas, thus the minimizing proposed impervious areas. The proposed concrete sidewalk areas
that sheet into adjacent depressed (2-inches) landscaped parkway to capture the 85th percentile
storm and reduce run-off into the street. These areas are considered Self-retaining DMAs per
Section 5.2.3 of the BMP Design Manual and illustrated on the DMA Exhibit.
See Attachment lb for qualifying site design BMP calculations.
Identify whether any of the following features, activities, and/or pollutant source areas will be
present (select all that apply):
On-site storm drain inlets
Interior floor drains and elevator shaft sump pumps
Interior parking garages
Need for future indoor & structural pest control
Landscape/Outdoor Pesticide Use
fl Pools, spas, ponds, decorative fountains, and other water features
E Food service
Refuse areas
E Industrial processes
LI Outdoor storage of equipment or materials
LI Vehicle and Equipment Cleaning
LI Vehicle/Equipment Repair and Maintenance
LI Fuel Dispensing Areas
LI Loading Docks
LI Fire Sprinkler Test Water
LI Miscellaneous Drain or Wash Water
Plazas, sidewalks, and parking lots
15
Identification of Receiving Water Pollutants of Concern
Describe path of storm water from the project site to the Pacific Ocean (or bay, lagoon, lake or
reservoir, as applicable):
From the project site, runoff flows to the Buena Vista Lagoon and to the Pacific Ocean.
List any 303(d) impaired water bodies within the path of storm water from the project site to the
Pacific Ocean (or bay, lagoon, lake or reservoir, as applicable), identify the
pollutant(s)/stressor(s) causing impairment, and identify any TMDLs for the impaired water
bodies:
303(d) Impaired Water Body Pollutant(s)/Stressor(s) TMDLs
Buena Vista Lagoon (904.21)
Indicator bacteria Bacteria (Est. TMDL
completion: 2008)
Nutrients Nutrients! Eutrophication (Est.
TMDL completion: 2019)
Sedimentation! Siltation
of Project Site Pollutants Identification
Sedimentation! Siltation (Est.
TMDL completion: 2019)
Identify pollutants expected from the project site based on all proposed use(s) of the site (see
BMP Design Manual Appendix B.6):
Pollutant
Not Applicable to the
Project Site
Expected from the
Project Site
Also a Receiving
Water Pollutant of
Concern
Sediment LI
Nutrients LI
Heavy Metals LI LI
Organic Compounds LI LI
Trash & Debris
Oxygen Demanding
Substances LI
Oil &Grease LI LI
Bacteria & Viruses LI
Pesticides LI LI
I
1 16
Hydromodification Management Requirements
Do hydromodification management requirements apply (see Section 1.6 of the BMP Design
Manual)?
LI Yes, hydromodification management flow control structural BMPs required.
El No, the project will discharge runoff directly to existing underground storm drains
discharging directly to water storage reservoirs, lakes, enclosed embayments, or the
Pacific Ocean.
No, the project will discharge runoff directly to conveyance channels whose bed and bank
are concrete-lined all the way from the point of discharge to water storage reservoirs,
lakes, enclosed embayments, or the Pacific Ocean.
El No, the project will discharge runoff directly to an area identified as appropriate for an
exemption by the WMAA for the watershed in which the project resides.
Description / Additional Information (to be provided if a 'No' answer has been selected above):
Storm water runoff from the project site flows southwest along Grand Avenue Street, enters a
storm drain on Grand Avenue, and ultimately discharges to the Buena Vista Lagoon. Based on
Section 1.6 of the City of Carlsbad BMP Design Manual, the City has the discretion to exempt a
PDP from hydromodification management requirements if discharge is conveyed via a concrete
lined system to an encased embayment (i.e. lagoon). Pursuant to the study approved by the
City of Carlsbad titled "Hydromodification Exemption Analyses for Select Carlsbad Watersheds"
dated September 17, 2015 prepared by Chang Consultants, the hydrologic and hydraulic
analyses performed showed that the hardened system downstream of the project draining to the
lagoon conveys the 10-year storm event, the discharge point has proper energy dissipation and
the outlet is within the 100-year flood limits.
Critical Coarse Sediment Yield Areas*
Ibis Section only required if hydromodification management requirements apply
Based on the maps provided within the WMAA, do potential critical coarse sediment yield
areas exist within the project drainage boundaries?
LI Yes
No, No critical coarse sediment yield areas to be protected based on WMAA maps
If yes, haveany of the optional analyses presented in Section 6.2 of the BMP Design Manual
been performed?
LII 6.2.1 Verification of Geomorphic Landscape Units (GLUs) Onsite
LI 6.2.2 Downstream Systems Sensitivity to Coarse Sediment
LI 6.2.3 Optional Additional Analysis of Potential Critical Coarse Sediment Yield Areas Onsite
LI No optional analyses performed, the project will avoid critical coarse sediment yield areas
identified based on WMAA maps
If optional analyses were performed, what is the final result?
LII No critical coarse sediment yield areas to be protected based on verification of GLUs
onsite
El 17
I
I
I
El
I
E Critical coarse sediment yield areas exist but additional analysis has determined that
protection is not required. Documentation attached in Attachment 8 of the SWQMP.
LII Critical coarse sediment yield areas exist and require protection. The project will implement
management measures described in Sections 6.2.4 and 6.2.5 as applicable, and the areas
are identified on the SWQMP Exhibit.
Discussion I Additional Information:
Hydromodification requirements are not required for this project.
I
I
I 18
I
11
I
I
I
I
Flow Control for Post-Project Runoff*
*This Section only required if hydromoditication management requirements apply
List and describe point(s) of compliance (POCs) for flow control for hydromodification
management (see
Section 6.3.1). For each POC, provide a POC identification name or number correlating to the
project's HMP Exhibit and a receiving channel identification name or number correlating to the
project's HMP Exhibit.
Hydromodification requirements are not required for this project.
Has a geomorphic assessment been performed for the receiving channel(s)?
LII No, the low flow threshold is 0.102 (default low flow threshold)
L Yes, the result is the low flow threshold is 0.102
U Yes, the result is the low flow threshold is 0.302
LI Yes, the result is the low flow threshold is 0.502
If a geomorphic assessment has been performed, provide title, date, and preparer:
Discussion I Additional Information: (optional)
I
I
I
I
I
I
I
I 19
1
1
Other Site Requirements and Constraints
When applicable, list other site requirements or constraints that will influence storm water
management design, such as zoning requirements including setbacks and open space, or
local codes governing minimum street width, sidewalk construction, allowable pavement
types, and drainage requirements.
On-site soil classification from NRCS Web Soil Survey is Type B. Infiltration testing performed
by Advanced Geotechnical Solutions, Inc. indicated that the soils located in the areas of the
proposed biofiltration basins have relatively high infiltration rates when thoroughly wet, similar
to typical Type B soils. However, the geotechnical engineer has stated that "infiltration is not
feasible due to the potential for water intrusion and potential for additional hydrostatic pressure
on subterranean garage. Accordingly infiltration on the 800 Grand portion of the site project is
not feasible." Therefore, the biofiltration basins will be lined with an impermeable liner to prevent
infiltration into native soils.
Currently, Grand Avenue lacks an underground storm drain system. This requires the proposed
WQ-BMPs and storm drain pipes to discharge flows onto Grand Avenue. Because the existing
and proposed slope of the site is relatively flat, the depths of the detention basins is very limited.
Optional Additional Information or Continuation of Previous Sections As Needed
I
I
I
I
I
L
20
I
I
I
I
I
I
I
City ,of
Carlsbad
STANDARD PROJECT
REQUIREMENT
CHECKLIST
E-36
nDnSvL.
Land Development Engineering
1635:Faradw Avenue
.'(m 502- 2750
www cailsbadca gov
Project Information
Project NmeBUU Grand Avehue
Priect ID CT 1E-09/PP 16-1
DWG No or Building Permit No
Source Control B MPs
At dvelopmn projects must implement source control BtvlPs SC-1 through SC-13 where applicable and feasible See
Chapter 4 and Appendix E.1 of the BMP Design Manual for information to implern ent source control aMPs shown in this
checklist.
Answer each category below pursuant to the following
Yes means the project will implement the source control 81VIP as described in Chapter 4 and/or Appendix El of the
Model BMP Design Manual Discussion/justification is not required
No means the BMP is applicable to the project but is not feasible to implement Discussion/justification jrriust be
provided Please add attachments if more space is needed
N/A means the BMP is not applicable at the project site because the croject does not include the feature that is
addressed by the BMP (e g the project has no outdoor materials sti tiije areas). 1 ii .iur 'itificatiun may be
Provided.
Source Control Requirement Applied?
Sc I Preve tion of Illicit Disch I es ntj the MS4 iz (es I F No r-777
Discussion/justification if SC-11' not implemented:
Acknowledge thtan itlicitdischarge is any'dischprgeto.tii&.MS4 that it not composed eiitir&y bf.*ash *ter.
Provide educational mdterlals to pta ant illicit discharges as a uornporOnt otthe Operation and Mintvnsnoe Plan (O&M
Oil
SC-2: Storm Drain:Sténciling orSignegé 0 ?es 0 No IN/A
Discussion/justification if SC -2 not implemented
No onsitestormd rain in Iths proposed
SC-3 Protect Outdoor Materials Storage Areas from Rainfall Run On Runoff and Wind D es Do Dispersal
Discussio.n/justificatioi .ifSC-3 not;implementedi
No outdoor materials storage areas proposed
E-36 Page 1 df 4 Reased 03/16
21
I
Source Control Requirement(continued) Applied?
SC-4 Protect. Materials Stored in Outdoor Work Areas from Rainfall, RunOn Runoff, and
Wind Dispersal es I 0 No
Discusion)iutification if SC-4 not implemented;.
No materials stored outdoors proposed
SC-S Protect Trash Storage Areas from Rainfall Run On Runoff, and Wind Dispersal 171 Yes 1 0 No 0 N/A
Disciissionljustifi'cation if SC-5 nqt implemented:
Trash areas will be concrete lined and covered to protect from rainfall
SC-6 Additional BMPs based on Potential Sources of Runoff Pollutants must answer for each source listed below arid
identify.additional BMPS.. (See Table in Appendix El Of BMPManuãl for guidanna).
On site storm drain inlets [I Yes, EJ No 0 N/A
171 Interior floor drains and elevator shaft sump pumps 171 Yes 0 No 0 N/A
Interior parking garages 0 Yes 0 No 0 N/A
Need for future indoor &. structural. pest control 171 Yes 0 No 0 N/A
171 Landscape/Outdoor Pesticide Use 171 Yes 0 No 0 N/A
El Pools, spas, ponds, decorative fountains, and other water features res 0 Yes 0 No 0 N/A
Food service DYes 0 No N/A
JZ Refuse areas 0 Yes 0 No 0 N/A
C] Industrial processes 0 Yes 0 No 0 N/A
El Outdoor toräe of equipment or materials 0 Yes 0 No 171 N/A
O Vehicle and Equipment Cleaning 0 Yes 0 No 0 N/A
E] Vehicle/Equipment Repair and Maintenance 0 Yes 0 No 0 N/A
El Fuel Dispensing Areas 0 Yes 0 No 0 N/A
Loading Docks, DYes 0 No 0 N/A
Fire SprThkler Test Water U Yes U No0 N/A
0 Misoeltsneous Drain or Wash Water 0 Yes 0 No 0 N/A
Plazas sidewalks and parking lots 1 171 Yes 0 No 0 N/A
For Yes' answers, identify the additional BMP per Appendix El. Provide justification for "No' answers.
.•lrispectand maintain interior parking garages and interior floor drains to prevent blockages and overflow.
Plant. pest-resistant or weIladapted plant varieties.such as drought tolerant and/or native plants in landscape areas.
Irrigation systems will be designed for the specific .water requirements of each landscape area Landscaping will be
designed to minimize irrigation and runoffj to promote surface infiltration where appropriate and to minimize the use of
fertilizers and pesticides that can contribute to storm water pollution
Refuse areas will be concrete lined and covered to protect from rainfall
-Plazas, sidewalks, and parking lots must beswept regularly to prevenitthe accumulation of litter and debris. Debris from
pressure washing must be collected to prevent entry into the storm drain system
Page 2 o 4 Revised 03/16
22
Site Design BMPs
All Jevelopmerit projects must iniplemerit sita deviqr ElAPs SE-1 tiiiuuLi SD-S where cppicedlle and leawbie. Se
h rter 4 and Appendix E.2 thru E.6 of the El P L1e6iri Wlanual for informition to implement site design BMPs shown in
this checklist-
Answer each category below pursuant to The following.
Yes means the project will implement the site design BMPs as described in Chapter 4 and/or Appendix E 2 thru E.6 of
the Model BMP Design Manual Discussion /justification is not required
No means the AMPs is applicable to the project but it is not feasible to implement. Discussion/justification must be
provided Please add attachments if more space is needed
N A- tile PtIPi is not applicable at the PFCJ sit— l- iii s the project does not include the feature that is
add essS t th P iPs p the project site has n I tirin not irS or-as to conserve) Discussiorrljustification may be
provided
Source Control Requirement Applied?
SID-1 SinsS.nin Natural Prooroerre °athways and Hdrotüi F&atL res :00 0 in U .11/A
Disct issi-in/justilication if SD-1 not irTtlementect
The project will nrrai.ntailn the overall cross lot drainage.
SD -2 Conserve Natural Areas Soils and Vegetation I 0 Yes I El No I Zl N/A
DicUssion/justifidat ion if 502 not impIernehtd:. •::
.
Thite is.O% mpervious pre.-ctevalopthent and 5% rnpervious.pst-deelopmént Although the project cannot
conserve natural areas theprøjectwill create -vegetated areas.
SD-3 Minimize Impervious Area I zi Yes I 0 No 7o 0 N/A
Discussic.nfjustificationif SD-3 not. irnplementedr
Project Will inccrratemulthstary architecture fo, minimize: ifllp'ehvibds area.
804 Minimize Soil Compaction . I 0 Yes: I El No: I N/A
Discussion/justification if SD-4 not implemented:
Project site has been previously graded
S0-5 Impervious Area Dispersion IZI Yes 1 El No I El N/A
Discusionfjustification if SD-5 not impléméntéd
Runoff from impervious wallay ar 5s ill.bé.djrec d,fb, landscape areas prior to discharging tbthe MS4.
E-36 Page 3 of 4 Revised 03/16
23
Source Control Requirement (continued) Applied?
SD4Runoff Collection El Yes No 0 N/A
DiscussiOnustification if SD-6 not imp!ernented.
Landscape arena are too ems to effectively collect and detain runoff, Permeable pavements are not considered feasible
as a substitute for impervious concrete areas.
SD-7 Landscaping with Native or Drought Tolerant Species I0 Yes I 0 No I a N/A
DiscuSsionustificatior!if SD-7 not implemented:
Landscape or pervious areas will incorporate native or drought tolerant landscape design Final selection of plant material
beeds.to be made by and. rchitectexpeincedWith LID techniques.
SD-8 Harvesting and Using Precipitation 0 Yes I 0 No 10 N/A
Discussionustification if SD-8 not implemented
Harvest and else is considered to be infeasible for the project site Project will utilize other LID strategies such as
minimizing impervious area to reduce the overall DCV of the site See Form 1-7 in Attachment Ic
I Page 4 of 4 Revised 03/16
1 24
SUMMARY OF PDP STRUCTURAL BMPS
PDP Structural BMPs
All PDPs must implement structural BMPs for storm water pollutant control (see Chapter 5 of the
BMP Design Manual). Selection of PDP structural BMPs for storm water pollutant control must
be based on the selection process described in Chapter 5. PDPs subject to hydromodification
management requirements must also implement structural BMPs for flow control for
hydromodification management (see Chapter 6 of the BMP Design Manual). Both storm water
pollutant control and flow control for hydromodification management can be achieved within the
same structural BMP(s).
PDP structural BMPs must be verified by the local jurisdiction at the completion of construction.
This may include requiring the project owner or project owner's representative to certify
construction of the structural BMPs (see Section 1.12 of the BMP Design Manual). PDP
structural BMPs must be maintained into perpetuity, and the local jurisdiction must confirm the
maintenance (see Section 7 of the BMP Design Manual).
Use this form to provide narrative description of the general strategy for structural BMP
implementation at the project site in the box below. Then complete the PDP structural BMP
summary information sheet (page 3 of this form) for each structural BMP within the project (copy
the BMP summary information page as many times as needed to provide summary information
for each individual structural BMP).
Describe the general strategy for structural BMP implementation at the site. This information
must describe how the steps for selecting and designing storm water pollutant control BMPs
presented in Section 5.1 of the BMP Design Manual were followed, and the results (type of
BMPs selected). For projects requiring hydromodification flow control BMPs, indicate whether
pollutant control and flow control BMPs are integrated or separate.
For the purpose of this SWQMP, the proposed site condition has been divided into (8) Drainage
Management Areas (DMAs): (2) Areas Draining to Biofiltration BMPs, (4) Self-mitigating DMAs
and (1) De Minimis DMAs, and (6) Self-Retaining DMAs. The DMAs have been delineated
based on onsite drainage patters and BMP locations.
A geotechnical investigation was provided by Advanced Geotechnical Solutions, Inc. to perform
infiltration testing and analyze storm water infiltration feasibility. Based on recommendations
from the geotechnical report, infiltration rates for the 800 Grand site are greater than 0.5 in/hr.
However, the conclusions and recommendation section in Appendix D state that "infiltration is
not feasible due to the potential for water intrusion and potential for additional hydrostatic
pressure on subterranean garage. Accordingly infiltration on the 800 Grand portion of the site
project is not feasible."
Since infiltration is considered infeasible, biofiltration basins were chosen as the structural BMP
for DMAs draining to IMPs.
25
I
I
The type of structural BMP chosen was also based on downstream receiving waters and
treatment goals. Since the project is located upstream from a receiving water that is 303(d) listed
for a nutrient pollutant, Nutrient Sensitive Media Design (BF-2) was selected for the biofiltration
BMPs to minimize the potential for export of nutrients from the media.
The biofiltration basins have been sized based on the minimum sizing factor of 3% for storm
water pollutant control requirements. The DCV for each DMA has been calculated based on the
proposed impervious and pervious areas draining to each BMP. Worksheet B.5-1 in Attachment
1 e further demonstrates that the DCV can be fully biofiltered within the storage layers, and the
stored effective depth draws down no longer than 36 hours.
Two (2) WQ-BMP biofiltration basins (BF-2) with no infiltration will be used for pollutant control and
peak flow control for the project stormwater runoff. In developed conditions, the basins will have
a surface depth of 1.2 feet. The basins will be configured with a 10-inch ponding layer above the
surface for storage volume, an 18-inch layer of amended soil below the surface, and a 10-inch
gravel storage layer below the amended soil layer to accommodate the French drain system.
Below the gravel layer the basins are lined to prevent infiltration into the underlying soil. Flows will
discharge from the basins via perforated underdrain pipe within the gravel layer to the receiving
storm drain system. A riser structure will be constructed within the BMPs with an emergency
overflow set 10-inches above the bottom of the basin, such that peak flows can be safely
discharged to the receiving storm drain system.
Six (6) self-retaining areas, located adjacent to the concrete sidewalk in Grand Avenue right of
way, are depressed (2-inches) landscaped parkway areas designed to capture reduce runoff.
Structural BMPs are not required for Self-Mitigating or De Minimis DMAs.
I
26
Structural BMP Summary Information
(Copy this page as needed to provide information for each individual proposed structural
BMP)
Structural BMP ID No. BMP-1A
DWG _509-1ASheet No. 2
Type of structural BMP:
LI Retention by harvest and use (H U-1)
LI Retention by infiltration basin (INF-1)
LI Retention by bioretention (INF-2)
LI Retention by permeable pavement (lNF-3)
LI Partial retention by biofiltration with partial retention (PR-1)
Biofiltration (BF-1)
LI Flow-thru treatment control with prior lawful approval to meet earlier PDP requirements
(provide BMP type/description in discussion section below)
LI Flow-thru treatment control included as pre-treatmentlforebay for an onsite retention or
biofiltration BMP (provide BMP type/description and indicate which onsite retention or
biofiltration BMP it serves in discussion section below)
LI Flow-thru treatment control with alternative compliance (provide BMP type/description in
discussion section below)
LI Detention pond or vault for hydromodification management
LI Other (describe in discussion section below)
Purpose:
Pollutant control only
LI Hydromodification control only
LI Combined pollutant control and
hydromodification control
LI Pre-treatment/forebay for another structural
BMP
LI Other (describe in discussion section below)
Discussion (as needed):
Hydromodification requirements are not required for this project. The WQ-BMP is for pollutant
control only.
1 27
I
Structural BMP Summary Information
(Copy this page as needed to provide information for each individual proposed structural
BMP)
Structural BMP ID No. BMP-1B
DWG Sheet No. 2
Type of structural BMP:
LI Retention by harvest and use (H U-1)
Retention by infiltration basin (IN F-1)
R Retention by bioretention (lNF-2)
LI Retention by permeable pavement (lNF-3)
fl Partial retention by biofiltration with partial retention (PR-1)
Biofiltration (BF-1)
LI Flow-thru treatment control with prior lawful approval to meet earlier PDP requirements
(provide BMP type/description in discussion section below)
LI Flow-thru treatment control included as pre-treatment/forebay for an onsite retention or
biofiltration BMP (provide BMP type/description and indicate which onsite retention or
biofiltration BMP it serves in discussion section below)
Flow-thru treatment control with alternative compliance (provide BMP type/description in
discussion section below)
LI Detention pond or vault for hydromodification management
LI Other (describe in discussion section below)
Purpose:
Pollutant control only
LI Hydromodification control only
LI Combined pollutant control and
hydromodification control
LI Pre-treatmentlforebay for another structural
BMP
LI Other (describe in discussion section below)
Discussion (as needed):
Hydromodification requirements are not required for this project. The WQ-BMP is for pollutant
control only.
I
I
I
I
I
I
I
1 28
I
ATTACHMENT 1
I BACKUP FOR PDP POLLUTANT CONTROL BMPS
This is the cover sheet for Attachment 1.
I Check which Items are Included behind this cover sheet:
Attachment Contents Checklist
Sequence
Attachment 1 a DMA Exhibit (Required) Z Included
See DMA Exhibit Checklist on the
back of this Attachment cover sheet.
(24"x36" Exhibit typically required)
Attachment 1 b Tabular Summary of DMAs Showing LI Included on DMA Exhibit in
DMA ID matching DMA Exhibit, DMA Attachment la
Area, and DMA Type (Required)* E Included as Attachment 1 b,
separate from DMA Exhibit
*Provide table in this Attachment OR
on DMA Exhibit in Attachment 1 a
Attachment lc Form 1-7, Harvest and Use Feasibility Z Included
Screening Checklist (Required unless U Not included because the entire
the entire project will use infiltration project will use infiltration BMPs
BMPs)
Refer to Appendix 13.3-1 of the BMP
Design Manual to complete Form 1-7.
Attachment 1 Form 1-8, Categorization of Infiltration M Included
Feasibility Condition (Required LI Not included because the entire
unless the project will use harvest and project will use harvest and use
use BMPs) BMPs
Refer to Appendices C and D of the
BMP Design Manual to complete
Form 1-8.
Attachment le Pollutant Control BMP Design E Included
Worksheets I Calculations (Required)
Refer to Appendices B and E of the
BMP Design Manual for structural
pollutant control BMP design
guidelines
I 29
I
I
I
I
I
I
I
I
I
I
I
Attachment la
I DMA Exhibit
11
I
I
I
I
I
I
I
I
U
I
I
I
I 30
I
Attachment lb
I Tabular Summary of DMAs and Design Capture Volume Calculations
1jJIJ lli
DMA Impervious Area Tabulation
Surface Name Surface Type Area (ft)
Ri Roof 16,118
PCC1 Concrete Sidewalk 1,659
Total Impervious Area (ft), 17,777
DMA Pervious Area Tabulation
Surface Name Surface Type Area (ft)
Li Landscape 1,694
Total Pervious Area (ft) 1,694
Total DMA (A) 19,101
Total Impervious Area (&) /Total DMA (ft) = Percent Impervious 930
Soil Type B
DMA Runoff Factor "C" per Appendix B.1 and B.2 0.85
85th Percentile Rainfall
Design Capture Volume (DVC) = (C)(I)(A) /121 808
1 31
I
: c\
DMA Impervious Area Tabulation
Surface Name Surface Type Area (ft)
R2 Roof 16,118
PCC2 Concrete Sidewalk 1,659
PCC3 Driveway 696
Total Impervious Area (ft)l 17,777
DMA Pervious Area Tabulation
Surface Name Surface Type Area (ft)
L2 Landscape 1,694
Total Pervious Area (ft2) 1,694
Total DMA (A) 20,537
Total Impervious Area (ft) /Total DMA (ft) = Percent Impervious 870
Soil Type B
DMA Runoff Factor "C" per Appendix B.1 and B.2 0.79
85th Percentile Rainfall (1)1
Design Capture Volume (DVC) = (C)(I)(A) /121 808
32
ri
I
Surface Name Surface Type Area (ft 2)
L3 Landscape 507
Subtotal Pervious Areal 507
Roof 0
PCC 0
Sub to l III] pctio us A rC,11 0
Total Self-Mitigauiig Areal 507
Percent Impervious Area (Not to Exceed 50/6)I 0%
Jki)
Surface Name Surface Type Area (ft 2)
L4 Landscape 507
Subtotal Pervious Areal 507
Roof 0
PCC 0
Subtotal Impervious Areal 0
Total Self-Mitigating Areal 507
Percent Impervious Area (Not to Exceed 50/6) I 0%
33
j
Surface Name Surface Type Area (ft 2)
L5 Landscape 507
Subtotal Pcrvious Area 507
Roof 0
PCC 0
Subtotal Impervious Area 0
Total Self-Mitigating Area 507
Percent Impervious Area (Not to Exceed 59/6)I 0%
Surface Name Surface Type Area (ft 2)
L6 Landscape 507
Subtotal Pervious Areal 507
Roof 0
PCC 0
Subtotal Impervious Areal 0
Total Self-Mitigating Areal 507
Percent Impervious Area (Not to Exceed 5%)I 0%
According to Chapter 5.2.1 of the City of Carlsbad BMP Design Manual, a DMA is considered "Self-
mitigating" if the DMA consists of natural or landscape areas that drain directly offsite. The self-
mitigating areas either are landscaped areas with native and/or drought tolerant species that do not
require regular application of fertilizers and pesticides, or disturbed soils that have been amended and
I aerated to promote water retention characteristics equivalent to undisturbed native topsoil.
The locations and limits of all Self-Mitigating DMAs are delineated on the DMA Exhibit.
L 34
I
I
Surface Name Surface Type Area (ft 2)
L Landscape 0
Subtotal Pervious Area 0
Roof 0
PCC5 PCC 444
Subtotal Impervious Areal 444
Total De Minimis Areal 444
Percent Impervious Area (Not to Exceed 29/6)! 1.14%
Total Percent Impervious Areal 1.14%
According to Chapter 5.2.2 of the City of Carlsbad BMP Design Manual, a DMA is considered "De
Minimis" if the DMA consists of areas that are very small and therefore not considered to be
significant contributor of pollutant, and are considered not practicable to drain to a BMP. The De
Minimis DMA is the concrete driveway and sidewalk areas connecting to the Grand Avenue. The
DMA is also less than 2 percent of the total added or replaced impervious surface of the project.
Furthermore, the portion of the site falling to this category is minimized through effective site design.
The locations and limits of all De Minimis DMAs are delineated on the DMA Exhibit.
35
36
Li
H
I
I
I
I
1
)i J
Surface Name Surface Type Area (ft 2)
Runoff Factor
(Table B.1-1)
Area x Runoff
Factor
L3 Landscape 183 0.1 18.3
PCC3 Concrete 375 0.9 337.5
Adjusted Surface Draining to Self-Retaining Area - (A) 355.8
Receiving Self-Retaining Surface Area - (B) 183
Self-Retaining Area Surface Typel Landscape
Ration of (A) to (B) 2.0:1
Pond Depth within Self-Retaining Area 2.0 in
Total Area of DMA 558
i: :.1(W
Surface Name Surface Type Area (ft 2)
Runoff Factor
(Table B.1-1)
Area x Runoff
Factor
L4 Landscape 251 0.1 25.1
PCC4 Concrete 547 0.9 492.3
Adjusted Surface Draining to Self-Retaining Area - (A) 517.4
Receiving Self-Retaining Surface Area - (B) 251
Self-Retaining Area Surface Typel Landscape
Ration of (A) to (B) 2.2:1
Pond Depth within Self-Retaining Area 2.0 in
Total Area of DMA 798
I
Surface Name Surface Type Area (ft 2)
Runoff Factor
(Table B.1-1)
Area x Runoff
Factor
L5 Landscape 203 0.1 20.3
PCC5 Concrete 585 0.9 526.5
Adjusted Surface Draining to Self-Retaining Area - (A) 546.8
Receiving Self-Retaining Surface Area - (B) 251
Self-Retaining Area Surface Typel Landscape
Ration of (A) to (B) 2.9:1
Pond Depth within Self-Retaining Area 0.0 in
Total Area of DMA 788
Surface Name Surface Type Area (ft 2)
Runoff Factor
(Table B.1-1)
Area x Runoff
Factor
L5 Landscape 186 0.1 18.6
PCC5 Concrete 552 0.9 496.8
Adjusted Surface Draining to Self-Retaining Area - (A) 515.4
Receiving Self-Retaining Surface Area - (B) 0
Self-Retaining Area Surface IMel Landscape
W-11"
Ration of (A) to (B) 3.0:1
Pond Depth within Self-Retaining Area 2.0 in
Total Area of DMA 738
37
IJ YJ \
Surface Name Surface Type Area (ft 2)
Runoff Factor
(Table B.1-1)
Area x Runoff
Factor
L5 Landscape 282 0.1 28.2
PCC5 Concrete 609 0.9 548.1
Adjusted Surface Draining to Self-Retaining Area - (A) 576.3
Receiving Self-Retaining Surface Area - (B) 0
Self-Retaining Area Surface Typel Landscape
Ration of (A) to (B) 2.2:1
Pond Depth within Self-Retaining Area 2.0 in
Total Area of DMA 891
Surface Name Surface Type Area (ft 2)
Runoff Factor
(Table B.1-1)
Area x Runoff
Factor
L5 Landscape 159 0.1 15.9
PCCS Concrete 356 0.9 320.4
Adjusted Surface Draining to Self-Retaining Area - (A)l 336.3
Receiving Self-Retaining Surface Area - (B) 0
Self-Retaining Area Surface Type Landscape
Ration of (A) to (B) 2.2:1
Pond Depth within Self-Retaining Area 2.0 in
Total Area of DMA 515
I According to Chapter 5.2.3 of the City of Carlsbad BMP Design Manual Self-retaining DMAs are
areas that are designed with site design BMPs to retain runoff to a level equivalent to pervious land.
The impervious areas (sidewalk in the city right of way in front of the project) are designed to drain
I onto adjacent pervious areas (landscaped areas) to effectively disconnect impervious from directly
draining to the storm drain system. The intent is to slow runoff discharges and reduce volumes.
- Underlying Hydrologic Soil Group Type B Soils is ideal for dispersion.
The locations and limits of all Self-retaining DMAs are delineated on the DMA Exhibit.
I 38
I
DMA Classification Quantity Subtotal DMA (ft 2) Subtotal DMA (acres)
Self-Mitigating DMAs 10 2,028 0.05
Self-Retaining DMAs 0 4,288 0
HU-1: Cistern 0 0 0
INF-l: Infiltration Basins 0 0 0
INF-2: Bioretention 0 0 0
INF-3: Permeable Pavement (Pollutant Control) 0 0 0
PR-I: Biofiltration with Partinl Retention 0 0 0
BF-1: Biofiltration 2 39,638 0.91
BF-2: Nutrient Sensitive Media Design 0 0 0
BF-3: Proprietary Biofiltration 0 0 0
FT-1: Vegetated Swales 0 0 0
Media Filters 0 0 0
Sand Filters 0 0 0
Dry Extended Detention Basin 0 0 0
Proprietary Flow-thru Treatment Control 0 0 0
De Minims DMAs 3 444 0.01
Total Project DMA 15 46,398 1.07
Total Parcel Area 41,906 0.96
Comment:
I
I 39
I
1
I
Attachment ic
Form 1-7, Harvest and Use Feasibility Screening Checklist
Is there a demand for harvested water (check all that apply) at the project site that is reliably present during the
wet season?
Toilet and urinal flushing
Landscape irrigation
Other:
If there is a demand; estimate the anticipated average wet season demand over a period of 36 hours. Guidance
for planning level demand calculations for toilet/urinal flushing and landscape irrigation is provided in Section
B.3.2.
I
Modified ETWU = ETOwetX [[(PF X HA)/IE] + SLA] X 0.015
Using an average value for HA over the 14 lots and Low Plant Water Use (per Table B.3-2);
Modified ETWU = 2.7 x [[(0.2 x 5,416)10.9] + 0] x 0.015
Modified ETWU= 487
Note: Total Landscape Area = 5,416 sf
Calculate the DCV using worksheet B-2.1.
DCV = 1.648 (cubic feet)
3a. Is the 36 hour demand greater 3b. Is the 36 hour demand greater than 3c. Is the 36 hour demand
than or equal to the DCV? 0.25DCV but less than the full DCV? less than 0.25DCV?
Yes Z No Yes Z No Yes
I
I
Harvest and use appears to be
feasible. Conduct more detailed
evaluation and sizing calculations to
confirm that DCV can be used at an
adequate rate to meet drawdown
criteria.
Harvest and use may be feasible.
Conduct more detailed evaluation and
sizing calculations to determine
feasibility. Harvest and use may only
be able to be used for a portion of the
site, or (optionally) the storage may
need to be upsrzed to meet long term
capture targets while draining in longer
than 36 hours.
Harvest and use is considered
to be infeasible.
I
I 40
I
Is harvest and use feasible based on further evaluation?
Yes, refer to Appendix E to select and size harvest and use BMPs.
No, select alternate BMPs
Harvest and use BMPs are considered infeasible. Drought tolerant landscape, as proposed in SD-7 in Form E-36,
requires low plant water use. Project will implement other LID strategies such as minimizing impervious area and
impervious area dispersion. The full DCV can be treated and detained in the proposed biofiltration basins.
41
Attachment 1 d
I Form 1-8, Categorization of Infiltration Feasibility Condition
I Form 1-8 consists of an excerpt taken from the below cited report. For the full report, see
Attachment 4.
I Revised Geotechnical Investigation and Foundation Design Recommendations for Proposed
Residential Multi-Family Podium Structure (Grand Ave) and Single Family (Home Ave) by
Advanced Geotechnical Solutions, Inc. December 28, 2017.
I
I
1 42
Attachment le
I Pollutant Control BMP Design Worksheets I Calculations
1 43
jj
Factor Category Factor Description Assigned
Weight \v)
Factor
Value
Product
(P
p=wxv
Soil assessment methods 0.25 2 0.5
Predominant soil texture 0.25 1 0.25
A Suitability
Assessment
Site soil variability 0.25 1 0.25
Depth to groundwater /
impervious layer 0.25 1 0.25
Suitability Assessment Safety Factor, SA = p 1.25
Level of pretreatment/ expected
sediment loads 0.5 1 0.5
B Design Redundancy/resiliency 0.25 1 0.25
Compaction during construction 0.25 1 0.25
Design Safety Factor, SB = Ep 1.0
Combined Safety Factor, SAX SB 1.25, use 2.0*
Observed Infiltration Rate, inch/hr, Kobserved BMP 1A BMP lB
2.83 ; 2.0 (corrected for test-specific bias)
Design Infiltration Rate, in/hi:, Kdesign = Kobserved / Stotai
BMP 1A:BMP lB
1.42• 1.0
Supporting Data
Briefly describe infiltration test and provide reference to test forms:
Percolation testing and infiltration rate results were provided by Advanced Geotechnical Solutions, Inc.
(see Attachment 4). The areas of the proposed biofiltration areas (two total) were tested utilizing City
of Carlsbad BMP Design Manual standards for percolation testing. Based up on the test results, the
infiltration rates were found to be:
P-i (BMP 1B) - Infiltration Rate = 1.42 in/hr
P-2 (BMP 1A) - Infiltration Rate = 1.0 in/hr
*The infiltration rate results provided by the geotechnical engineer use a factor of safety of 2.0.
At the direction of the geotechnical engineer, the infiltration rate will use a factor of safety of
2.0 to adopt a more conservative basin design.
1 44
I
I
I
I
I
-k .
1 lRemaining DCV after implementing retention BMPs 808 cubic-feet
PartialPartial Retention
2 Infiltration rate from Worksheet D.5-1 if partial infltration is feasible 0 in/hr.
3 Allowable drawdown time for aggregate storage below the underdrain 36 hours
4 Depth of runoff that can be infiltrated [Line 2 x Line 3] 0 inches
5 Aggregate pore space 0.4 in/in
6 Required depth of gravel below the underdrain [Line 4 / Line 5] 0 inches
7 Assumed surface area of the biofiltration BMP 604 sq-ft
8 Media retained pore space 0.1 in/in
9 Volume retained by BMP [[Line 4 + (Line 12 x Line 8)1/12] x Line 7 91 cubic-feet
10 DCV that requires biofiltration [Line 1 - Line 9] 718 cubic-feet
BMP Parameters
11 1 Surface Ponding [6 inch minimum, 12 in maximum] 10 inches
12 Media Thickness [18 inches minimum] 18 inches
13 Aggregate Storage above underdrain invert (12 inches typical - use 0 inches
. for sizing if aggregate is not over the entire bottom surface area 10 inches
14 Media available pore space 0.2 in/in
15 IMedia filtration rate to be used for sizing 5 in/hr.
Baseline Calculation
16 Allowable Routing Time for sizing 6 hours
17 Depth filtered during storm [Line 15 x Line 16] 30 inches
18 Depth of Detention Storage 17.6 inches [Line 11 + (Line 12 xLine 14) + (Line 13 xLine 5)]
19 Total Depth Treated [Line 17 + Line 181 1 47.6 linches
Option 1 - Biofilter 1.5 times the DCV
20 1 Required biofiltered volume [1.5 x Line 10] 1 1,077 cubic-feet
21 lRequired Footprint [Line 20 / Line19] x12 271 Jq-ft
2 - Store 0.75 of remaining DCV in pores and ponding ..22on
22 [Required Storage (surface + pores) Volume [0.75 x Line 10] 538
1sq_ft
cubic-feet
23 Jequired Footprint [Line 22 / Line 18] x 12 367
Footprint of the BMP
24 Area draining to the BMP 19,101 sq-ft
25 Adjusted Runoff Factor for drainage area (Refer to Appendix B.1 and B.2) 0.85
26 Minimum BMP Footprint [Line 24 x Line 25 x 0.03] 485 sq-ft
27 Footprint of the BMP = Maximum(Minimum(Line 21, Line 23), Line 26) 485 sq-ft
28 jUsed BMP Footprint F 485 1 sq-ft
I
I
I
1 jRemajninZ DCV after implementing retention BMPs 808 Icubic-feet
Partial Retention
2 Infiltration rate from Worksheet D.5-1 if partial infitration is feasible 0.0 in/hr.
3 Allowable drawdown time for aggregate storage below the underdrain 36 hours
4 Depth of runoff that can be infiltrated [Line 2 x Line 3] 0 inches
5 Aggregate pore space 0.4 in/in
6 Required depth of gravel below the underdrain [Line 4 / Line 5] 0 inches
7 Assumed surface area of the biofiltration BMP 604 sq-ft
8 Media retained pore space 0.1 in/in
9 Volume retained by BMP [[Line 4 + (Line 12 x Line 8)1/12] x Line 7 1 91 cubic-feet
10 JDCV that requires biofikration [Line 1 - Line 9] 718 cubic-feet
BMP Parameters
11 Surface Ponding [6 inch minimum, 12 in maximum] 10 inches
12 Media Thickness [18 inches minimum] 18 inches
13 Aggregate Storage above underdrain invert (12 inches typical - use 0 inches
For sizing if aggregate is not over the entire bottom surface area 10 inches
14 Media available pore space in/in
15 Media filtration rate to be used for sizing E!5] in/hr.
Baseline Calculation
16 Allowable Routing Time for sizing 6 hours
17 Depth filtered during storm [Line 15 x Line 16] 30 inches
18 Depth of Detention Storage 17.6 inches [Line Line (Line Line _11_+_(Line_12_x _14)_+_ _13_x _5)]
19 ITotal Depth Treated [Line 17 + Line 18] 47.6 inches
Option - Biofilter 1.5_ times _1 _the _DCV
20 Required biofiltered volume [1.5 x Line 10] 1,077 cubic-feet
21 lRequired Footprint [Line 20 / Linel9] x 12 271 sq-ft
Option 2 - Store 0.75 of remaining DCV in pores and ponding
22 IRequired Storage (surface + pores) Volume [0.75 x Line 10] 538 cubic-feet
23 lRequired Footprint [Line 22 / Line 18] x 12 367 sq-ft
Footprint of the BMP
24 1 Area draining to the BMP 20,537 E-ft
25 Adjusted Runoff Factor for drainage area (Refer to Appendix B.1 and B.2) 0.79
26 Minimum BMP Footprint [Line 24 x Line 25 x 0.03] 485 sq-ft
27 Footprint of the BMP = Maximum(Minimum(Line 21, Line 23), Line 26) 485 sq-ft
28 Used BMP Footprint 1 485 Isq-ft
1
I 46
I
I
I
I
I
W0iH-f125
ADD PEA. ORAtL sm
MP HflH EPDXYA.6VER-
12 7NICK CVCRE7E BASEMENT
RETAINING WALL AS 9IO4N ON
WE S11UCfl/RAL PLANS
ThJII.DING PERMIT p02017-0049)
4 PVC DRAINAGE PI'PE
FROM StaiR PUMP.
sEr MEP FoR OE1WLS
IMPERMEABLE LINER
(SIDES AND BOTTOM) T
I
FG £HOMV
ON PLANK
INLET
15,
LA)R
2'vc PIPE SLLEf-Aft ONE
SIZE LARGER 7W PIPE 0L4.
LANDSCAPE PARKWAY
AREAS DEPRESSED 2
'-C-8 RETAINING WALL C.
BI0FILTRA110N BASIN SECTION
?LTS. 3O 041L LINER NOTE' 30-MIL IMPERMEABLE LINER FOR B/OREIENI7ON
CONFORM TO THE FOLLOv6Nc SPECIFICATIONS* SPECIF7C CPA t47Y
(ASTM 0792) 2 (C/CC MIN.), TENSILE (ASJM 0882) 73
(LB4N-/4101H U/N) ELONGA liON AT BREAK (ASTM 0862) 380 (9
MIN); MODULUS (ASTM 0882) 30 01IN-00711 U/N) AND TEAR
S7RENCTh/ (ASThI 01004) 8 (LB/1N MIN), SEAM SHEAR STRENGTH
(ASTM 0882) 584 (LB/iN. MIN); SEAM PEEL STRENGTH (ASTM 0862)
15 (LB,* (N).
SEE COLORADO LINING !N7ERNA71ONAL PVC 30
/I17P: /AWW.COLORADOLINING,00M/PR000CTS/PVC,PDE) OR
APPROVED EQUAL.
L65-MIN PER 0-27
78.5' OF 3'• -PVC
PIPE B lOX PER 0-27
'6 RETAINING WALL
47
I
ATTACHMENT 2
BACKUP FOR PDP HYDROMODIFICATION CONTROL MEASURES
Project is not subject to Hydromodification requirements.
I
I
I
I 48
I
I ATTACHMENT 3
Structural BMP Maintenance Information
I Use this checklist to ensure the required information has been included in the Structural
BMP Maintenance Information Attachment:
I Preliminary Design/Planning/CEQA level submittal:
I Attachment 3 must identify:
Typical maintenance indicators and actions for proposed structural BMP(s) based
on Section 7.7 of the BMP Design Manual
I Final Design level submittal:
Attachment 3 must identify:
Specific maintenance indicators and actions for proposed structural BMP(s). This
shall be based on Section 7.7 of the BMP Design Manual and enhanced to reflect
actual proposed components of the structural BMP(s)
How to access the structural BMP(s) to inspect and perform maintenance
Features that are provided to facilitate inspection (e.g., observation ports,
cleanouts, silt posts, or other features that allow the inspector to view necessary
components of the structural BMP and compare to maintenance thresholds)
Manufacturer and part number for proprietary parts of structural BMP(s) when
applicable
Maintenance thresholds for BMPs subject to siltation or heavy trash (e.g., silt level
posts or other markings shall be included in all BMP components that will trap and
store sediment, trash, and/or debris, so that the inspector may determine how full
the BMP is, and the maintenance personnel may determine where the bottom of
the BMP is. If required, posts or other markings shall be indicated and described
on structural BMP plans.)
Recommended equipment to perform maintenance
When applicable, necessary special training or certification requirements for
inspection and maintenance personnel such as confined space entry or
hazardous waste management
I
I
I 49
I
Draft Maintenance Agreement
Purpose and Scope
This section was prepared based on the Chapter 7 of City of Carlsbad BMP Design Manual The
goal is to insure that the Project proponent accepts responsibility for all facilities maintenance,
repair, and replacement from the time they are constructed until the ownership and maintenance
responsibilities is formally transferred to the new owner. Facilities shall be maintained in perpetuity
and comply with the City's self-inspection, reporting, and verification requirements.
Inspection, Maintenance Log and Self-Verification Forms
Fill the forms on the following pages for each BMP using the maintenance schedule here and the
inspection-maintenance checklists in Section VII. These forms shall be signed by the responsible
party and retained for at least (5) years. Use the DMA Exhibit for the location of BMPs. (Make
duplicate copies of these forms and fill out those, not the original ones.)
I III. Updates, Revisions and Errata
This maintenance plan is a living document and based on the changes made by maintenance
N personnel, such as replacement of mechanical equipments, addition maintenance procedure
shall be added and maintenance plan shall be kept up to date.
I Please add the revisions and updates to the maintenance plan to this section if any, these
revisions maybe transmitted to the City at any time. However, at a minimum, updates to the
maintenance plan must accompany the annual inspection report.
I IV. Introduction
I The 800 Grand Avenue project is a 0.96-acre project that includes the development of a multi-
unit apartment complex with underground parking. The project is located at 800 Grand Avenue
in the City of Carlsbad, west of the Interstate 5 freeway. The project site is bounded on the east
by Hope Avenue and on the west by Jefferson Street.
I Storm flows affecting the site are limited to the rainfall that lands directly on the property. The I project site drains to one Point of Compliance (POC), located at the southwest corner of the
project site on Grand Avenue.
I Runoff from the developed project site is drained to two (2) onsite biofiltration BMPs (Water
Quality-BMPs or WQ-BMPs) for water quality purposes (the project is not subject to
hydromodification requirements). Once flows are routed via the proposed WQ-BMPs, all flows
are then conveyed via storm drain to the aforementioned POC.
I Runoff that is not able to gravity flow to the receiving biofiltration basins will be directed to an
underground vault located underneath the garage. A sump pump located in a pump room will
pump storm water runoff to the biofiltration basins for storm water treatment.
I 50
I
I
I
I
I
[I
I
I
I
V. Responsibility for Maintenance
I A. General
I
Owner will enter into a Stormwater Facilities Maintenance Agreement (SWFMA) with the City
of Carlsbad to maintain designated facilities herein this section for the 800 Grand
Condominiums.
The SWFMA will serve as the mechanism to ensure that proper inspection and maintenance
is done in an efficient and timely manner.
Responsible Party/Owner
McKellar-McGowan
I
888 Prospect Street, #330
La Jolla, Ca 92037
858-342-9725
I Owner will have the direct responsibility for maintenance of Stormwater controls. A Home
Owner's Association (HOA) shall be formed, or establish another mechanism to the
I satisfaction of the City. Funding for the maintenance activities shall be provided by Owner,
the HOA, or other mechanism to the satisfaction of the City.
I Whenever the property is sold and whenever designated individual change, immediately the
updated contact information must be provided to the City of Carlsbad.
I B. Staff Training Program
Staff training and education program shall be carried out twice a year, once prior to the rainy
season (October iSt) and once during the early dry season (April 30th).
The inspection and maintenance training program consists of the operation and function of
I the biofiltration basins. Please refer to the BMP Maintenance Fact Sheet for INF-3 Permeable
Pavement for fact sheets and checklists.
It is the responsibility of Owner to convey the maintenance and inspection information to the
employees. Maintenance personnel must be qualified to properly maintain stormwater
management facilities. Inadequately trained personnel can cause additidnal problems
resulting in additional maintenance costs.
Records
Owner shall retain education, inspection, and maintenance forms and documents for at least
five (5) years.
Safety
I 51
I
I
El
I
I
I
Keep safety considerations at the forefront of inspection procedures at all times. Likely
hazards should be anticipated and avoided. Never enter a confined space (outlet structure,
manhole, etc) without proper training or equipment. A confined space should never be
entered without at least one additional person present.
If a toxic or flammable substance is discovered, leave the immediate area and contact the
local Sheriff at 911.
Potentially dangerous (e.g., fuel, chemicals, hazardous materials) substances found in the
areas must be referred to the local Sheriff's Office immediately for response by the Hazardous
Materials Unit. The emergency contact number is 911.
Vertical drops may be encountered in areas located within and around the facility. Avoid
walking on top of retaining walls or other structures that have a significant vertical drop. If a
vertical drop is identified within the pond that is greater than 48" in height, make the
appropriate note/comment on the maintenance inspection form.
VI. Summary of Drainage Areas and Stormwater Facilities
A. Drainage Areas
I The project has been divided into (2) Drainage Management Areas (DMAs) draining to storm
water treatment facilities, or biofiltration BMPs. The DMAs have been delineated based on
onsite drainage patters and BMP locations. DMA-1A and DMA-113 discharge into the
I proposed biofiltration BMP-1 A and BMP-1 B. The storm water treatment BMPs serve to meet
water quality and peak flow reduction requirements for the project site.
Roof drains will collect runoff and discharge into proposed biofiltration basins. Runoff from
the concrete sidewalk area will be intercepted by a private storm drain system and conveyed
I to an underground vault located underneath the garage. The underground vault will be sized
as a cistern to store the volume from a 100 year storm event. Trench drains within the
underground garage will also collect miscellaneous storm water runoff and will convey flow to
I the underground vault. A sump pump located in a pump room will pump storm water runoff
to the biofiltration basins for treatment. For stormwater runoff greater than a 100-year storm
event, a backup pump will start automatically to empty the underground vault.
I B. Treatment and Flow-Control Facilities
I Two (2) WQ-BMP biofiltration basins (BF-2) with no infiltration are located within the project
site and are responsible for handling water quality requirements for POC-1. In developed
conditions, the basins will have a surface depth of 1.2 feet. The basins will be configured with
I a 10-inch ponding layer above the surface for storage volume, an 18-inch layer of amended
soil below the surface, and a 10-inch gravel storage layer below the amended soil layer to
accommodate the French drain system. Below the gravel layer the basins are lined to prevent
1 52
I
I
I
I
I
I
I
infiltration into the underlying soil. Flows will discharge from the basins via perforated
underdrain pipe within the gravel layer to the receiving storm drain system. A riser structure
will be constructed within the BMPs with an emergency overflow set 10-inches above the
bottom of the basin, such that peak flows can be safely discharged to the receiving storm
drain system. The storm drain system will outlet at proposed curb outlets on Grand Avenue.
See the DMA Exhibit for the location of BMPs.
The biofiltration facilities are designed to filter water through vegetation and engineered soil
media prior to discharge via underdrain or overflow to the downstream conveyance system.
Because the facilities are lined to prevent infiltration, the system is designed to provide enough
hydraulic head to move flows through the underdrain connection to the storm drain system.
The facilities are also designed with an overflow outlet, such that peak flows can be safely
discharged to the receiving storm drain system. Treatment is achieved through filtration,
sedimentation, sorption, biochemical processes and plant update. The biofiltration facilities
for this project have been sized for pollutant control only, based on the City of Carlsbad BMP
Design Manual.
Facility Documentation
Please see the following pages regarding the BMPs details and maintenance fact sheets.
Maintenance Schedule and Checklist
Fill out the Checklists in the following pages for each BMP. The required maintenance activities
are at the end of this section. At the discretion of the Project proponent, a qualified Stormwater
company may be hired to perform the required inspection and maintenance and provide
necessary reports.
I
I
I
I
I
53
I
I
I
I
n
H
I
ATTACHMENT 3
City standard Single Sheet BMP (SSBMP) Exhibit
I
I
I
I
Li
I
I
I
I
I
I
I
I Attachment 4
Geotechnical Study
I See Revised Geotechnical Investigation and Foundation Design Recommendations for Proposed
Residential Multi-Family Podium Structure (Grand Ave) and Single Family (Home Ave) by
I Advanced Geotechnical Solutions, Inc. December 28, 2017 on CD following this page.
I
I
I
I
I)RA]AA(iEMAAA(jLMLAT AREA LAHIBTL LEGEND SYMBOL
800 GRAND A VENUE D
DMA AREA (SQ FT)
MA BOUNDARY
L
,W
DMA NAME
i5T1
PROPERTY LINE
1 POINT OF CONCENTRATION PQC-i
I \"
PRO)
LINE
/1 1 '
SELF-MITIGATING DMA SM-i
/ j\____ I I I SELF-RETAINING DMA SR-i
DE MINIMIS DMA DMIN-1
1 ROOF AREA R
/ /C 1L I / \
LANDSCAPE AREA L
FLOW DIRECTION
ROOF AREA, R
... .......
PROPOSED CONCRETE, FCC 8 11 k .......................................................................................................
.........................................................................................
...............
....
....
i
-*
PROPOSED BIOHLTRATION BMP
-
. H / \
(WATER QUALITY—BMP)
RIP RAP ENERGY DISSIPATOR
.................. ........... ...... ...... .................. ......................... -i'
Oh or
........... FQ
J ............. .......... ..... r
PROJECT CHARACTERISTICS
PARCEL AREA 0.96 ACRES
DISTURBED AREA 1.07 ACRES
PROPOSED IMPERVIOUS AREA 0.90 ACRES
PROPOSED PERVIOUS AREA 0.17 ACRES
SOIL TYPE B
DEPTH TO GROUNDWATER >20 FEET
r 'I I f • I
- L I I I I I I I I :::•:• IL I I
B " ( .::.::
RHD
-* I —.. .............. . ...... ...— — — f dif- 11
'I I WIDTH = 025' (TG) 24"x24" BROOKS
- .. -'H - :
— JPERTY I ADD PEA GRAVEL, SEAL 7-DOWNSPOUT CATCH BASIN W/ L GRATED INLET R I I TOP WITH EPDXY/LIN JI BMP FOOTPRINT / W
...................... I ..............
I I FG SHOWN z')
-____ _______
= 12" THICK CONCRETE BASEMENT 4 ON PLA
SM-2 - - .•::: I ___
RETAINING WALL AS SHOWN ON . SPLASH SM-i 507 SF _____
DRAINAGE/PUMP I I ,1' THE S TRUC TURAL PLANS PAD 12 ==PLAN 77N 507 SF — --- - VAULT r--
____
NCRETE I 1 (BUILDING PERMIT #Pc20170049 ----------1Q'
— - - - — -_ I -- * I - WALK,
I I MULCH LAYER L L J J I. L ) I •:.::.:: : P 2 1
_ k I 4" PVC DRAINAGE PIPE JNt
FROM SUMP PUMP PVC PIPE SLEEVE-MIN ONE
I __ l
I
L
_ / \ I SEE MEP FOR DETAILS 8' MI SIZE LARGER THE PIPE DIA
LJ I II I k NGINEERE LANDSCAPE PARKWAY
SD -7 pçy SD -7 ___ - - ___ - ___ (1 IMPERMEABLE LINER SOIL, MEDIA AREA S DEPRESSED 2" (SIDES AND BOTTOM) 'P GRA
VIN BIOFIIARA T BA t'Y , ri111i .J
H ) 1 1 gç 4 3
+ L
L6 FS 5ZOO
tv
507 3F —27 6.5 MIN PER D 1 9 - 4 L u L 1 / Jo M
IMPERMEABLE
IL 6 "PERFORA TED 185' OF 3" Pvc
/ - o / 4 LINER* PVC PIPE PIPE 10% PER D-27
PCC4 'TEXISTREE b4\N / SR-5 ' --/X/s'i TREE 1 N N \\ C-6 RETAINING WALL
- - TO REIMIN DMIN1 ONCRETE 891 SF - - TO R MAIN \ N \ / C-6 RETAINING
788 SE
TW T L738 SF EXIST. TREE / :. .
50 SE BIOFILTRATION BASIN SECTION
X-1 1 0 *30 MIL LINER NO TE: 30-MIL IMPERMEABLE LINER FOR B/ORE TENT/ON
TO REMAIN. / . I 0 CONFORM TO THE FOLLOWING SPEC/FICA T/ONS: SPECIFIC GRA VI TY
7'LL V 1._ii V I I I (ASTM D792): 1.2 (C/CC, MIN.), TENSILE (ASTM D882): 73 7 i1i / ________
.. 0o I 1 0 (LB//N- WIDTH, MIN); ELONGATION AT BREAK (ASTM D882): 380 (
.0 IWIN); MODULUS (ASTV D882): JO (LBIIN-WIDTH, MIN.), AND TEAR
STRENGTH (ASTM D1004): 8 (LB/IN, MIN); SEAM SHEAR STRENGTH
.
- --. (ASTM D882) 58.4 (LB//N, MIN), SEAM PEEL STRENGTH (ASTM D882)
__ ------ N :.__::.:....* - _
-
15(LB//N,/N).
0 SEE COLORADO LINING INTERNATIONAL :1 / TIONAL PVC 30
&WWWCOLORADOLINING.COM.IPRODUCTSIPVC.PDE) OR
- - N / 1 APPROVED EQUAL.
SELF-MITIGATING DMAS: SELF-RETAINING DMAS:
VEGETATION IN THE NATURAL OR LANDSCAPE AREA IS NATIVE OR NON-NATIVE DROUGHT TOLERANT SPECIES. SELF-RETAINING DMAS ARE AREAS THAT ARE DEPRESSED (2-INCHES) LANDSCAPED PARKWAY AREAS
SOILS ARE UNDISTURBED NATIVE TOPSOIL, OR DISTURBED SOILS ARE AMENDED AND AERATED TO PROMOTE DESIGNED TO CAPTURE AND REDUCE RUNOFF.
WATER RETENTION CHARACTERISTICS EQUIVALENT TO UNDISTURBED NATIVE TOPSOIL.
INCIDENTAL IMPERVIOUS AREAS ARE LESS THAN 5 PERCENT OF THE SELF-MITIGATING AREA. 20' 10' 0' 20' 40' 60'
BMP FOOTPRINT••
BASIN PROPOSED BASIN AREA
BMP-1A 485 SF
BMP-1B 485 SF
(W) (w) ",.. (W)(
LID AND SITE DESIGN:
I SD- i I MAINTAIN NATURAL DRAINAGE PATHWAYS AND HYDROLOGIC FEATURES
ISD-31 MINIMIZE IMPERVIOUS AREA
I SD-5 I IMPERVIOUS AREA DISPERSION
ISD-7 I LANDSCAPING WITH NATIVE OR DROUGHT TOLERANT SPECIES
SOURCE CONTROL BMPS:
I SC-fl PREVENTION OF ILLICIT DISCHARGES INTO THE MS4
I SC-2 I STORM DRAIN STENCILING AND SIGNAGE
I SC- Si PROTECT TRASH STORAGE AREAS
I SC-6 I ADDITIONAL BMPS BASED ON POTENTIAL RUNOFF POLLUTANTS:
E1 INTERIOR FLOOR DRAINS AND ELEVATOR SHAFT SUMP PUMPS
EJ INTERIOR PARKING GARAGES
J NEED FOR FUTURE INDOOR & STRUCTURAL PEST CONTROL
i:1 LANDSCAPE/OUTDOOR PESTICIDE USE
EEl TRASH OR REFUSE AREAS
PLAZAS, SIDEWALKS, DRIVEWAYS, AND PARKING LOTS
I
IMPERVIOUS AREAS CALCULATED WITHIN THE SELF-MITIGATED AREA ARE NOT BE HYDRAULICALLY
CONNECTED TO OTHER IMPERVIOUS AREAS UNLESS IT IS STORM WATER CONVEYANCE SYSTEM (SUCH AS SCALE 1" = 20'
BROW DITCHES)
THE SELF-MITIGATING AREA IS HYDRAULICALLY SEPARATE FROM DMAS THAT CONTAIN PERMANENT STORM SHEET CITY OF CARLSBAD SHEETS
WATER POLLUTION CONTROL BMPS I ENGINEERING DEPARTMENT 1
DE MINIMIS DMAS: DMA EXHIBIT
DE MINIMIS DMAS ARE AREAS THAT ARE VERY SMALL, AND THEREFORE NOT CONSIDERED TO BE 800 GRAND AVENUE SIGNIFICANT CONTRIBUTORS OF POLLUTANTS, AND ARE CONSIDERED NOT PRACTICAL TO DRAIN TO A BMP
DE MINIMIS DMAS ARE AREAS ABUT THE PERIMETER OF THE DEVELOPMENT SITE.
RECORD
_____________________________________________________
THE PORTION OF THE SITE FALLING INTO THIS CATEGORY IS MINIMIZED THROUGH EFFECTIVE SITE DESIGN. bhxinc.
EACH DE MINIMIS DMA SHOULD BE LESS THAN 250 SQUARE FEET AND THE SUM OF ALL DE MINIMIS DMAS land planning, cM] engineedngh. surveylng CDP 16-25 SHOULD REPRESENT LESS THAN 2 PERCENT OF THE TOTAL ADDED OR REPLACED IMPERVIOUS SURFACE OF 5115 AVENIDA ENCINAS
THE PROJECT SUITE "L": DRAWING NO
TWO DE MINIMIS DMAS CANNOT BE ADJACENT TO EACH OTHER AND HYDRAULICALLY CONNECTED CARLSBAD, CA 92008-4387 INITIAL DATE L 509-1A
(760) 931-8700
BMP TABLE
INSpfl* *
BMP ID # BMP TYPE
J
SYMBOL
f
CASQA NO. QUANTITY
J
DRAWING NO. SHEET NO.(S) MAINTENANCE
FREQUENCY FREQUENCY
I
TREATMENT CONTROL
BIOFILTRATION +++++ TC-32 485 SF. 4AREA 509-IA QUARTERLY SEMI-ANNUALLY
BIOFILTRATION TC-32 485 SF 509-1A 4 QUARTERLY SEMI-ANNUALLY
LOW IMPACT DESIGN (L.LD.)
ROOFDRAINTO 0 SD-il 5 EA 509-1A 4 ANNUALLY ANNUALLY LANDSCAPING
SIDEWALK DRAIN
TO LANDSCAPING . : : : SD-il 6 EA 509-1A 4 ANNUALLY ANNUALLY
SOURCE CONTROL
®INTERIOR FLOOR SC-44 DRAINS AND
ELEVATOR 0
SHAFT SUMP
PUMPS
INTERIOR
PARKING SC-44
GARAGES
FUTURE INDOOR
& STRUCTURE SC-41
PEST CONTROL
LANDSCAPE O /OUTDOOR SC-41
PESTICIDE USE
(jij)ITRASH ENCLOSURE [Lull SD-32
PLAZAS, . . SD-Il SIDEWALKS,
DRIVEWAYS,
AND PARKING
LOTS
,'IL/U rcui (M,M VCL, CML
/ / L'P% I L'Ul I't1...)IIV VV/
TOP WiTH EPDXY/LINER—..\ JI BMP FOOTPRINT / GRATED INLET ,
R W * CHOOSE FROM THE LIST BELOW FOR COMPLETING THE FIELDS
FG SHOWN I 2 IN THE INSPECTIONS & MAINTENANCE FRENQUENCY COLUMNS
12" THICK CONCRETE BA SEMEN T— I 41 ON PLAN-.. I RETAINING WALL AS SHOWN ON I SPLASH II ANNUAL
THE STRUCTURAL PLANS rPAD / li 2' 1LANT/NG SEMI-ANNUALLY
(BUILDING PERMIT #Pc2017-0049 ,'-r --ji L---------I I w'I-A.._i I QUARTERLY
4" PVC DRAINAGE PIPEff
SEE MEP FOR DETAILS
IMPERMEABLE LINER _>Z
(SIDES AND BOTTOM)
SUMP PUMP.
MIN
XQ(/ )Q<SO/L MED/A )9QK \,X)X
rr-i
IX XX I
1-I SIZE
J—MULcH
(3" M!t9
AAREASI
LA YER blMUN I lILY
MONTHLY PVC PIPE SLEEVE-MIN ONEFROM AS NEEDED LARGER THE PIPE DIA NONE
DSCAPE PARK WA Y WEEKLY
DEPRESSED 2" 1 TIME PER YEAR
1
2 TIMES PER YEAR
29: ' TIrtAQ D= VAI
II1 S)9A q6f1 Q J I IIvJ I L I
4 TIMES PER YEAR
FS 57. 00
LI± '
65" MIN PER D-27 /.
IMPERMEABLE "—Jo 6 "PERFORA TED 18.5' OF 3" Pvc
LINER* PVC PIPE PIPE 1.0% PER D-27
C-6 RETAINING WALL dir C-6 RETAINING WALL
BIOFILTRATION BASIN SECTION
N. TS, *30 MIL LINER NOTE: Jo MIL IMPERMEABLE LINER FOR BIORETENTION
CONFORM TO THE FOLLOWING SPECIFICATIONS.- SPECIFIC GRA VI TY
(ASTM 0792): 1.2 (C/CC, MIN.); TENSILE (ASTM 0882): 73
(LB/IN- WID TH, MIN); ELONGA TI ON A T BREAK (ASTM 0882): 380 (
MIN); MODULUS (A S TM 0882): 30 (LB//N- WID TH, MIN.); AND TEAR
STRENGTH (AS TM D1004): 8 (LB//N, MIN); SEAM SHEAR STRENGTH
(A S TM D882) 58.4 (LB//N, MIN); SEAM PEEL STRENGTH (AS TM 0882)
15 (LB//N, IN). GRAPHIC SCALE 1"=20'
SEE COLORADO LINING INTERNATIONAL PVC 30
H TTP: //WWW. COL ORADOL/NING. COM/PRODUC TS'/P VC. POE) OR
APPROVED EQUAL. 0 20 40 60
SHEET CITY OF CARLSBAD SHEETS
1 ENGINEERING DEPARTMENT 1
SINGLE SHEET BMP SITE PLAN
800 GRAND AVENUE
RECORD COPY
INI11AL DATE
PROJECT NO
CDP 16-25
REVISION DESCRIPTION
DATE INITIAL DATE INITIAL DRAWING NO
509-1A OTHER APPROVAL CITY APPROVAL U