HomeMy WebLinkAboutCDP 2020-0018; FORESTER RESIDENCE; STORM WATER QUALITY MANAGEMENT PLAN; 2022-10-01CITY OF CARLSBAD
PRIORITY DEVELOPMENT PROJECT (PDP)
STORM WATER QUALITY MANAGEMENT PLAN (SWQMP)
FOR
FORESTER RESIDENCE
(4464 ADAMS STREET)
PROJECT ID: CDP2020-0018
DRAWING No. DWG 533-8A
ENGINEER OF WORK:
JOHN S. RIVERA, C73878
PREPARED FOR:
JOHN AND JULIE FORESTER
300 CARLSBAD VILLAGE DRIVE, SUITE 108A-355
CARLSBAD, CA 92008
760-535-4343
PREPARED BY:
FUSION ENGINEERING AND TECHNOLOGY
1810 GILLESPIE WAY, SUITE 207
EL CAJON, CA 92020
858-736-2800
DATE:
OCTOBER 2022
TABLE OF CONTENTS
Certification Page
Project Vicinity Map
FORM E-34 Storm Water Standard Questionnaire
Site Information
FORM E-36 Standard Project Requirement Checklist
Summary of PDP Structural BMPs
Attachment 1: Backup for PDP Pollutant Control BMPs
Attachment 1a: DMA Exhibit
Attachment 1b: Tabular Summary of DMAs and Design Capture Volume Calculations
Attachment 1c: Harvest and Use Feasibility Screening (when applicable)
Attachment 1d: Categorization of Infiltration Feasibility Condition (when applicable)
Attachment 1e: Pollutant Control BMP Design Worksheets / Calculations
Attachment 1f: Trash Capture BMP Requirements
Attachment 2: Backup for PDP Hydromodification Control Measures
Attachment 2a: Hydromodification Management Exhibit
Attachment 2b: Management of Critical Coarse Sediment Yield Areas
Attachment 2c: Geomorphic Assessment of Receiving Channels
Attachment 2d: Flow Control Facility Design
Attachment 3: Structural BMP Maintenance Thresholds and Actions
Attachment 4: Single Sheet BMP (SSBMP) Exhibit
Attachment 5: Geotechnical Report
CERTIFICATION PAGE
Project Name: Forester Residence (4464 Adams Street)
Project ID: CDP2020-0018, DWG 533-8A
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 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 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 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 Engineer in Responsible Charge of design of storm water BMPs
for this project, of my responsibilities for project design.
_____________________________________C73878 Exp. 6/30/2023
Engineer of Work's Signature, PE Number & Expiration Date
John S. Rivera, P.E. C73878________________________________________________________
Print Name
Fusion Engineering & Technology_______________
Company
10/7/2022_________________________________
Date
~
(/;
0. 73878
. 6/30/
PROJECT VICINITY MAP
PROJECT
SITE
VICINITY
CITY OF OCEANSIDE
PACIFIC
OCEAN
7a
MAP
CITY OF ENCINITAS
NOT TO
SCALE
CITY OF VISTA
ITY OF
N MARCOS
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 (BMPs) into the project design per Carlsbad BMP Design Manual (BMP Manual). To view the BMP Manual,
refer to the Engineering Standards (Volume 5).
This questionnaire must be completed by the applicant in advance of submitting for a development application
(subdivision, discretionary permits and/or construction 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 PROJECT’ requirements, ‘STANDARD PROJECT’ with
TRASH CAPTURE REQUIREMENTS, or be subject to ‘PRIORITY DEVELOPMENT PROJECT’ (PDP) requirements.
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 of the 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 completed and signed questionnaire must be submitted with each development project application. Only one completed
and signed questionnaire is required when multiple development applications for the same project are submitted
concurrently.
PROJECT INFORMATION
PROJECT NAME: APN:
ADDRESS:
The project is (check one): New Development Redevelopment
The total proposed disturbed area is: ft2 ( ) acres
The total proposed newly created and/or replaced impervious area is: ft2 ( ) acres
If your project is covered by an approved SWQMP as part of a larger development project, provide the project ID and the
SWQMP # of the larger development project:
Project ID SWQMP #:
Then, go to Step 1 and follow the instructions. When completed, sign the form at the end and submit this with your
application to the city.
This Box for City Use Only
City Concurrence:
YES NO Date: Project ID:
By:
E-34 Page 1 of 4 REV 09/21
Development Services
Land DevelopmentEngineering
1635 Faraday Avenue
(760) 6022750
www.carlsbadca.gov
STORM WATER STANDARDS
QUESTIONNAIRE
E-34
4464 ADAMS STREET - CDP 2020-0018 - 553-8A 206-192-08
4464 ADAMS STREET
X
30,880
12,763
II
C cicyof
Carlsbad
□
I O I O I
□
II
E-34 Page 2 of 4 REV 09/21
STEP 1
TO BE COMPLETED FOR ALL PROJECTS
To determine if your project is a “development project”, please answer the following question:
YES NO
Is your project LIMITED TO routine maintenance activity and/or repair/improvements to an existing building
or structure that do not alter the size (See Section 1.3 of the BMP Design Manual for guidance)?
If you answered “yes” to the above question, provide justification below then go to Step 6, mark the box stating “my project
is not a ‘development project’ and not subject to the requirements of the BMP manual” and complete applicant
information.
Justification/discussion: (e.g. the project includes 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.(3), please answer
the following questions:
Is your project LIMITED 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:
a) Designed and constructed to direct storm water runoff to adjacent vegetated areas, or other non-
erodible permeable areas; OR
b) Designed and constructed to be hydraulically disconnected from paved streets or roads; OR
c) 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
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?
If you answered “yes” to one or more of the above questions, provide discussion/justification below, then go to Step 6, 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 constructed in accordance with
the USEPA Green Street guidance):
If you answered “no” to the above questions, your project is not exempt from PDP, go to Step 3.
X
X
X
X
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E-34 Page 3 of 4 REV 09/21
* Environmentally Sensitive Areas include but are not limited to all Clean Water Act Section 303(d) impaired water bodies; areas designated as Areas of Special
Biological Significance by the State Water Resources Control Board (Water Quality Control Plan for the San Diego Basin (1994) and amendments); water bodies
designated with the RARE beneficial 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 of San Diego; Habitat
Management Plan; and any other equivalent environmentally sensitive areas which have been identified by the City.
STEP 3
TO BE COMPLETED FOR ALL NEW OR REDEVELOPMENT PROJECTS
To determine if your project is a PDP, please answer the following questions (MS4 Permit Provision E.3.b.(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, industrial, residential, mixed-use,
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.
3. Is 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 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 (Standard Industrial
Classification (SIC) code 5812).
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.
5. Is 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
a land area or facility for the temporary parking or storage of motor vehicles used personally for
business or for commerce.
6. Is your project a new or redevelopment project that creates and/or replaces 5,000 square feet or more
of impervious street, road, highway, freeway or driveway surface collectively over the entire project
site? A street, road, highway, freeway or driveway is any paved impervious surface used for the
transportation of automobiles, trucks, motorcycles, and other vehicles.
7. 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
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).*
8. Is your 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 any one of the following Standard Industrial Classification (SIC)
codes: 5013, 5014, 5541, 7532-7534, or 7536-7539.
9. Is 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)? 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.
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?
11. Is 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
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 6, 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, complete the
trash capture questions..
X
X
X
X
X
X
X
X
X
X
X
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STEP4
TO BE COMPLETED FOR REDEVELOPMENT PROJECTS THAT ARE PRIORITY DEVELOPMENT PROJECTS (PDP)
ONLY
Complete the questions below regarding your redevelopment project (MS4 Permit Provision E.3.b.(2)):
YES NO
Does the redevelopment project result in the creation or replacement of impervious surface in an amount
of Jess than 50% of the surface area of the previously existing development? Complete the percent
impervious calculation below:
Existing impervious area (A) = 8 863 sq . ft. □ !XI
Total proposed newly created or replaced impervious area (B) = 12,763. sq.~
Percent impervious area created or replaced (B/At100 = 144 %
If you answered •yes", the structural BMPs required for PDP apply only to the creation or replacement of Impervious
surface and not the entire development. Go to step 6, check the first box stating, "My project is a PDP .. ." and complete
applicant information.
If you answered "no,• the structural BM P's required for PDP apply to the entire development. Go to step 6, check the first
box statino "Mv oroject is a PDP ... • and comolete aoolicant information.
STEP5
TO BE COMPLETED FOR STANDARD PROJECTS
Complete the question below regarding your Standard Project (SDRWQCB Order No. 2017-0077):
YES NO
Is the Standard Project within any of the following Priority Land Use (PLU) categories?
R-23 (15-23 du/ac), R-30 (23-30 du/ac), Pl (Planned Industrial), CF (Community Facilities), GC (General □ □ Commercial), L (Local Shopping Center), R (Regional Commercial), V-B (Village-Barrio), VC (Visitor
Commercial), 0 (Office), VC/OS (Visitor Commercial/Open Space), Pl/O (Planned Industrial/Office), or
Public Transoortation Station
If you answered "yes", the 'STANDARD PROJECT is subject to TRASH CAPTURE REQUIREMENTS. Go to step 6,
check the third box stating, "My project Is a 'STANDARD PROJECT' subject to TRASH CAPTURE REQUIREMENTS
••• ft and complete applicant information.
If you answered "no·, your project is a 'STANDARD PROJECT'. Go to step 6, check the second box stating, "My project is
a 'STANDARD PROJECT ... " and complete aoolicant information.
STEP&
CHECK THE APPROPRIATE BOX AND COMPLETE APPLICANT INFORMATION
1XJ My project is a PDP and must comply with PDP stormwater requirements of the BMP Manual. I understand I must
prepare a Storm Water Quality Management Plan (SWQMP) per E-35 template for submittal at time of application.
0 My project is a 'STANDARD PROJECT' OR EXEMPT from PDP 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.
0 My project is a 'STANDARD PROJECT' subject to TRASH CAPTURE REQUIREMENTS and must comply with
TRASH CAPTURE REQUIREMENTS of the BMP Manual. I understand I must prepare a TRASH CAPTURE Storm
Water Quality Management Plan (SWQMP) per E-35A template for submittal at time of application.
Note: For projects that are close to meeting the PDP threshold, staff may require detailed impervious area calculations ,,
and exhibits to verify if 'STANDARD PROJECT' stormwater requirements apply.
D My project is NOT a 'development project' and is not subject to the requirements of the BMP Manual.
Applicant Information and Signature Box
Applicant Name: JOHN FO!ER ~ Applicant Title: PROPERTY OWNER
AppUcant Signature: Q, _ Date: LD-,f --z.02.:z_
E-34 Page4 of 4 REV 09121
SITE INFORMATION CHECKLIST
Project Summary Information
Project Name Forester Residence (4464 Adams Street)
Project ID CDP2020-0018
Project Address 4464 Adams Street
Carlsbad, CA 92008
Assessor's Parcel Number(s) (APN(s))206-192-08-00
Project Watershed (Hydrologic Unit)904.31 (Carlsbad 904)
Parcel Area
0.533 Acres (23,222 Square Feet)
Existing Impervious Area
(subset of Parcel Area)0.203 Acres (8,863 Square Feet)
Area to be disturbed by the project
(Project Area)0.709 Acres (30,880 Square Feet)
Project Proposed Impervious Area
(subset of Project Area)0.293 Acres (12,763 Square Feet)
Project Proposed Pervious Area
(subset of Project Area)0.416 Acres (18,117 Square Feet)
Note: Proposed Impervious Area + Proposed Pervious Area = Area to be Disturbed by the Project.
This may be less than the Parcel Area.
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
Vacant, undeveloped/natural
Description / Additional Information:
Existing single family residence, driveway and concrete patio, with vegetated and non-vegetated
pervious/landscape areas.
Existing Land Cover Includes (select all that apply):
Vegetative Cover
Non-Vegetated Pervious Areas
Impervious Areas
Description / Additional Information:
The current site includes one residential home, driveway, patio, and landscaping.
Underlying Soil belongs to Hydrologic Soil Group (select all that apply):
NRCS Type A
NRCS Type B
NRCS Type C
NRCS Type D
Approximate Depth to Groundwater (GW):
GW Depth < 5 feet
5 feet < GW Depth < 10 feet
10 feet < GW Depth < 20 feet
GW Depth > 20 feet
Existing Natural Hydrologic Features (select all that apply):
Watercourses
Seeps
Springs
Wetlands
None
Description / Additional Information:
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]:
The site is currently developed as an existing single family residence. The site contains impervious
surfaces including roof, A.C. driveway pavement, and concrete patio and walkways. The site drains in a
northeast to southwest direction, in an urban condition, and flows overland towards Adams Street via
the existing driveway and southwest facing slope. No offsite areas are conveyed through the site.
Description of Proposed Site Development and Drainage Patterns
Project Description / Proposed Land Use and/or Activities:
The project proposes demolition of the existing single-family residence, and related flatwork, and
replaces with new single-family residence and new flat work. The project also proposes a right of way
dedication along Adams Street and Highland Drive, closing of existing driveway along Adams Street,
construction of new driveway along Highland Drive, and graded bench along Adams Street with new a.c.
berm. The project also includes proposed AC berm along Adams Street, downstream of the project, in
order to provide a continuous hard lined conveyance system from the project discharge to the
downstream storm drain catch basin. The right of way dedication along Adams Street and Highland
Avenue are as conditioned upon the project per the previously approved Coastal Development Permit
for the project. The a.c. berm downstream of the project along Adams Street is proposed to provide a
continuous hard line channel to the Agua Hedionda Lagoon in order to satisfy Hydromodification
Exemption requirements.
List/describe proposed impervious features of the project (e.g., buildings, roadways, parking lots,
courtyards, athletic courts, other impervious features):
Proposed impervious surfaces include new roof area, patio, and driveway. A minor roadway widening
along Adams Street has been conditioned upon the project. The current project proposes a.c. berm
along the project frontage along Adams street and the Owner was conditioned apart of the Coastal
Development Permit process to enter into a lien agreement with the City to install Curb and Gutter at a
future date if and when Adams Street is formally widened per future City CIP project. The improvements
along Adams Street are considered self-mitigating with adjacent landscaped slope area and not
hydraulically connected to the site.
List/describe proposed pervious features of the project (e.g., landscape areas):
The project proposes landscaped slopes.
Does the project include grading and changes to site topography?
þYes
No
Description / Additional Information:
The project proposes minor slope and pad grading which is negligible with respect to existing drainage
condition flow paths.
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
Pools, spas, ponds, decorative fountains, and other water features
Food service
Refuse areas
Industrial processes
Outdoor storage of equipment or materials
Vehicle and Equipment Cleaning
Vehicle/Equipment Repair and Maintenance
Fuel Dispensing Areas
Loading Docks
Fire Sprinkler Test Water
Miscellaneous Drain or Wash Water
Plazas, sidewalks, and parking lots
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):
Storm water from the site flows along Adams Street to a curb inlet and is then piped to the Agua
Hedionda Lagoon.
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
Agua Hedionda Lagoon Toxicity Yes
Identification of Project Site Pollutants
Identify pollutants anticipated 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
Anticipated from the
Project Site
Also a Receiving Water
Pollutant of Concern
Sediment X x
Nutrients X x
Heavy Metals X
Organic Compounds X
Trash & Debris X x
Oxygen Demanding
Substances X x
Oil & Grease X
Bacteria & Viruses X x
Pesticides X
Hydromodification Management Requirements
Do hydromodification management requirements apply (see Section 1.6 of the BMP Design Manual)?
Yes, hydromodification management flow control structural BMPs required.
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.
þNo, 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.
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):
The discharge of runoff from the site is ‘hardlined’ to the Agua Hedionda Lagoon and is therefore exempt
based on the Section 6.1 of the BMP Design Manual. This section in the manual allows PDPs to be exempt
from hydromodification requirements where the project discharges stormwater runoff to existing
underground storm drains discharging directly to water storage reservoirs, lakes, or enclosed
embayments (i.e. lagoon). Record research determined that the storm drain located downstream of the
site conveys site runoff and empties directly into the lagoon at an invert below the mean high tide water
surface elevation.
Critical Coarse Sediment Yield Areas*
*This 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?
Yes
No, No critical coarse sediment yield areas to be protected based on WMAA maps
If yes, have any of the optional analyses presented in Section 6.2 of the BMP Design Manual been
performed?
6.2.1 Verification of Geomorphic Landscape Units (GLUs) Onsite
6.2.2 Downstream Systems Sensitivity to Coarse Sediment
6.2.3 Optional Additional Analysis of Potential Critical Coarse Sediment Yield Areas Onsite
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?
No critical coarse sediment yield areas to be protected based on verification of GLUs onsite
Critical coarse sediment yield areas exist but additional analysis has determined that protection is not
required. Documentation attached in Attachment 8 of the SWQMP.
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 / Additional Information:
Project discharges directly to Agua Hedionda Lagoon via hard line conveyance system and is thus HMP
exempt.
Flow Control for Post-Project Runoff*
*This Section only required if hydromodification 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.
Has a geomorphic assessment been performed for the receiving channel(s)?
No, the low flow threshold is 0.1Q2 (default low flow threshold)
Yes, the result is the low flow threshold is 0.1Q2
Yes, the result is the low flow threshold is 0.3Q2
Yes, the result is the low flow threshold is 0.5Q2
If a geomorphic assessment has been performed, provide title, date, and preparer:
Discussion / Additional Information: (optional)
Project discharges directly to Agua Hedionda Lagoon via hard line conveyance system and is thus HMP
exempt.
Other Site Requirements and Constraints
When applicable, list other site requirements or constraints that will influence storm water management
design, suchas zoning requirements including setbacks and open space, or City codes governing minimum
street width, sidewalk construction, allowable pavement types, and drainage requirements.
Optional Additional Information or Continuation of Previous Sections As Needed
This space provided for additional information or continuation of information from previous sections as
needed.
E-36 Page 1 of 3 Revised 09/21
Development Services
Land Development Engineering
1635 Faraday Avenue
(760) 6022750
www.carlsbadca.gov
STANDARD PROJECT
REQUIREMENT
CHECKLIST
E-36
Project Information
Project Name: FORESTER RESIDENCE 4464 ADAMS STREET
Project ID:
DWG No. or Building Permit No.:
Baseline BMPs for Existing and Proposed Site Features
Complete the Table 1 - Site Design Requirement to document existing and proposed site features and the BMPs to be
implemented for them. All BMPs must be implemented where applicable and feasible. Applicability is generally
assumed if a feature exists or is proposed.
BMPs must be implemented for site design features where feasible. Leaving the box for a BMP unchecked means it
will not be implemented (either partially or fully) either because it is inapplicable or infeasible. Explanations must be
provided in the area below. The table provides specific instructions on when explanations are required.
Table 1 - Site Design Requirement
A. Existing Natural Site Features (see Fact Sheet BL-1)
1. Check the boxes below for each existing feature on
the site.
1. Select the BMPs to be implemented for each identified feature. Explain
why any BMP not selected is infeasible in the area below.
SD-G
Conserve natural
features
SD-H
Provide buffers around waterbodies
Natural waterbodies
Natural storage reservoirs & drainage corridors --
Natural areas, soils, & vegetation (incl. trees) --
B. BMPs for Common Impervious Outdoor Site Features (see Fact Sheet BL-2)
1. Check the boxes below for each
proposed feature.
2. Select the BMPs to be implemented for each proposed feature. If neither BMP SD-B nor
SD-I is selected for a feature, explain why both BMPs are infeasible in the area below.
SD-B
Direct runoff to pervious
areas
SD-I
Construct surfaces from
permeable materials
Minimize size of
impervious areas
Streets and roads Check this box to confirm
that all impervious areas on
the site will be minimized
where feasible.
If this box is not checked,
identify the surfaces that
cannot be minimized in area
below, and explain why it is
infeasible to do so.
Sidewalks & walkways
Parking areas & lots
Driveways
Patios, decks, & courtyards
Hardcourt recreation areas
Other: _______________
C. BMPs for Rooftop Areas: Check this box if rooftop areas are proposed and select at least one BMP
below.
If no BMPs are selected, explain why they are infeasible in the area below.
(see Fact
Sheet BL-3)
SD-B
Direct runoff to pervious areas
SD-C
Install green roofs
SD-E
Install rain barrels
X X
X
X X
X
X
X
X
X X
CDP 2020-0018
533-8A
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Carlsbad
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E-36 Page 2 of 3 Revised 09/21
D. BMPs for Landscaped Areas: Check this box if landscaping is proposed and select the BMP below
SD-K Sustainable Landscaping
If SD-K is not selected, explain why it is infeasible in the area below.
(see Fact
Sheet BL-4)
Provide discussion/justification for site design BMPs that will not be implemented (either partially or fully):
Baseline BMPs for Pollutant-generating Sources
All development projects must complete Table 2 - Source Control Requirement to identify applicable requirements for
documenting pollutant-generating sources/ features and source control BMPs.
BMPs must be implemented for source control features where feasible. Leaving the box for a BMP unchecked means it
will not be implemented (either partially or fully) either because it is inapplicable or infeasible. Explanations must be
provided in the area below. The table provides specific instructions on when explanations are required.
Table 2 - Source Control Requirement
A. Management of Storm Water Discharges
1. Identify all proposed outdoor
work areas below
Check here if none are proposed
2. Which BMPs will be used to prevent
materials from contacting rainfall or
runoff?
(See Fact Sheet BL-5)
Select all feasible BMPs for each work area
3. Where will runoff from the
work area be routed?
(See Fact Sheet BL-6)
Select one or more option for each
work area
SC-A
Overhead
covering
SC-B
Separation
flows from
adjacent
areas
SC-C
Wind
protection
SC-D
Sanitary
sewer
SC-E
Containment
system
Other
Trash & Refuse Storage
Materials & Equipment Storage
Loading & Unloading
Fueling
Maintenance & Repair
Vehicle & Equipment Cleaning
Other: _________________
B. Management of Storm Water Discharges (see Fact Sheet BL-7)
Select one option for each feature below:
•Storm drain inlets and catch basins … are not proposed
will be labeled with stenciling or signage to
discourage dumping (SC-F)
•Interior work surfaces, floor drains &
sumps …
are not proposed
will not discharge directly or indirectly to the MS4
or receiving waters
•Drain lines (e.g. air conditioning, boiler,
etc.) …
are not proposed
will not discharge directly or indirectly to the MS4
or receiving waters
•Fire sprinkler test water … are not proposed will not discharge directly or indirectly to the MS4
or receiving waters
Provide discussion/justification for source control BMPs that will not be implemented (either partially or fully):
X
X
X
X
X
X
X
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D
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E-36 Page 3 of 3 Revised 09/21
Form Certification
This E-36 Form is intended to comply with applicable requirements of the city’s BMP Design Manual. I certify that it has
been completed to the best of my ability and accurately reflects the project being proposed and the applicable BMPs
proposed to minimize the potentially negative impacts of this project's land development activities on water quality. I
understand and acknowledge that the review of this form by City staff is confined to a review and does not relieve me as
the person in charge of overseeing the selection and design of storm water BMPs for this project, of my responsibilities for
project design.
Preparer Signature: Date:
Print preparer name:
09/02/2021
JOHN S. RIVERA
12/29/2021
.,.._. : .. I ... .. .• .-1-:-4·-■~, ~ .. ==-•~-"i I If· ~ .. _ ..
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 City 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 City 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
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 together or separate.
The following steps were taken in determining the proposed development’s BMPs.
Step 1A: The site was divided into Drainage Management Areas (DMA) based on the proposed drainage
characteristics of the site. Each DMA was then evaluated on whether it could be considered ‘Self-
mitigating’ or ‘De minimis’ or ‘Self-retaining’. It was determined that DMA 2 could be considered as a
‘Self-mitigating’ Area and therefore compliant with Pollutant Control BMP Sizing requirements.
Step 1B: DMA1 did not meet with descriptions stated in Step 1A. The associated area runoff factors
were then used to determine the DCV.
Step 2: A Harvest and Use assessment was then performed and was determined to be infeasible for this
site.
[Continue on next page as necessary.]
[Continued from previous page – This page is reserved for continuation of description of general
strategy for structural BMP implementation at the site.]
Step 3: Next, the infiltration capacity of the site was assessed. Per the geotechnical engineer’s report, it
was recommended that infiltration BMPs not be used at the site due to the proximity of the slopes along
the site’s lower reaches as well as the sites existing compacted fill soils. Therefore, the proposed
method of treatment will be via biofiltration.
Step 4: Due to the infiltration infeasibility constraint, the site proposes to achieve the biofiltration
treatment performance standard via a proprietary modular biofiltration device. This device will be flow-
based. The required treatment flowrate was then determined using the equation:
Q(85th) = 1.5 x RF x 0.2 x A
A Modular Wetland Unit, Model L-4-8 was determined to have the treatment capacity necessary to
comply with treatment performance requirements.
To comply with volume retention requirements, a tree well will be added to the site’s design with
sufficient volume retention capacity. Since the entirety of DMA does not drain to the proposed tree
well, a supplemental calculation has been provided to demonstrate that the area tributary to the tree
well generates excess DCV versus the total project retention requirements.
Structural BMP Summary Information
[Copy this page as needed to provide information for each individual proposed structural BMP]
Structural BMP ID No. BF-3-1
DWG 533-8A Sheet No. ___7_______
Type of structural BMP:
Retention by harvest and use (HU-1)
Retention by infiltration basin (INF-1)
Retention by bioretention (INF-2)
Retention by permeable pavement (INF-3)
Partial retention by biofiltration with partial retention (PR-1)
Biofiltration (BF-1)
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)
Detention pond or vault for hydromodification management
þ Other (describe in discussion section below)BF-3 Compact Proprietary Biofiltration
Purpose:
þPollutant control only
Hydromodification control only
Combined pollutant control and hydromodification control
Pre-treatment/forebay for another structural BMP
Other (describe in discussion section below)
Discussion (as needed):
This project will implement storm water treatment of its impervious surfaces by biofiltration via
proprietary biofiltration BMP. An onsite Modular Wetland Unit Model L-4-8 is proposed to achieve the
treatment BMP performance standard for the area tributary to DMA 1. The tributary area includes
impervious surfaces suchas roof, patio, sidewalk, and driveway. The pervious areas will be the remaining
landscaped areas. The calculated treatment flowrate from the site was determined to be 0.063 cfs, which
after applying the 1.5 factor produces a design flow rate of 0.095. The flowrate provided by the Modular
Wetland Unit Model L-4-8 is 0.115 cfs. Therefore, the treatment performance standard is met.
This project proposes a tree well within DMA1 to achieve retention volume requirements. The County of
San Diego Automated Stormwater Pollutant Control Worksheet (Version 2.0) was used to determine the
amount of retention volume required. Based on the site’s infiltration restriction due to its proximity to
slopes, the worksheet determined that the required retention volume is 11 cubic feet. The project
proposes a 6-foot canopy tree well which is calculated to retain 16 cf. Therefore, the volume retention
requirement is met.
ATTACHMENT 1
BACKUP FOR PDP POLLUTANT CONTROL BMPS
This is the cover sheet for Attachment 1.
Check which Items are Included behind this cover sheet:
Attachment
Sequence
Contents Checklist
Attachment 1a DMA Exhibit (Required)
See DMA Exhibit Checklist on the back of
this Attachment cover sheet. (24”x36”
Exhibit typically required)
Included
Attachment 1b Tabular Summary of DMAs Showing
DMA ID matching DMA Exhibit, DMA
Area, and DMA Type (Required)*
*Provide table in this Attachment OR on
DMA Exhibit in Attachment 1a
Included on DMA Exhibit in
Attachment 1a
Included as Attachment 1b, separate
from DMA Exhibit
Attachment 1c Form I-7, Harvest and Use Feasibility
Screening Checklist (Required unless the
entire project will use infiltration BMPs)
Refer to Appendix B.3-1 of the BMP
Design Manual to complete Form I-7.
Included
Not included because the entire
project will use infiltration BMPs
Attachment 1d Form I-8, Categorization of Infiltration
Feasibility Condition (Required unless
the project will use harvest and use
BMPs)
Refer to Appendices C and D of the BMP
Design Manual to complete Form I-8.
Included
Not included because the entire
project will use harvest and use
BMPs
Attachment 1e Pollutant Control BMP Design
Worksheets / Calculations (Required)
Refer to Appendices B and E of the BMP
Design Manual for structural pollutant
control BMP design guidelines
Included
X
X
X
X
X
ATTACHMENT 1a
DMA EXHIBIT
Use this checklist to ensure the required information has been included on the DMA Exhibit:
The DMA Exhibit must identify:
Underlying hydrologic soil group
Approximate depth to groundwater
Existing natural hydrologic features (watercourses, seeps, springs, wetlands)
Critical coarse sediment yield areas to be protected (if present)
Existing topography and impervious areas
Existing and proposed site drainage network and connections to drainage offsite
Proposed grading
Proposed impervious features
Proposed design features and surface treatments used to minimize imperviousness
Drainage management area (DMA) boundaries, DMA ID numbers, and DMA areas (square footage or
acreage), and DMA type (i.e., drains to BMP, self-retaining, or self-mitigating)
Structural BMPs (identify location and type of BMP)
STOP
H I G H L A N D D R I V E
ADAMS STREET
DMA 2
DMA 1
SOURCE CONTROL BMPS SEE FORM E-36 IN
SWQMP
• PREVENTION OF ILLICIT DISCHARGE TO THE
MS4
·PROTECT TRASH STORAGE AREAS FROM
RAINFALL, RUN-ON, RUNOFF, AND WIND
DISPERSAL
·NEED FOR INDOOR PEST CONTROL
·LANDSCAPE/OUTDOOR PESTICIDE USE
·SWEEP SIDEWALKS REGULARLY
SITE DESIGN BMPS SEE FORM E-36 IN SWQMP
·MAINTAIN NATURAL DRAINAGE PATHWAYS
AND HYDROLOGIC FEATURES
·MINIMIZE IMPERVIOUS AREA
·MINIMIZE SOIL COMPACTION
·IMPERVIOUS AREA DISPERSION
·RUNOFF COLLECTION
• LANDSCAPING WITH NATIVE OR DROUGHT
TOLERANT PLANTS
NOTES
·GROUNDWATER DEPTH > 20 FEET
• SOIL TYPE 'B'
·NO CCSYAS PRESENT ONSITE OR DRAINING
THROUGH THE PROJECT BOUNDARY PER
WMAA MAP
PROPERTY LINE
DMA BOUNDARY
SUBAREA ACREAGE
DMA ICON
HYDROLOGIC SOIL TYPE
POINT OF COMPLIANCE
DMA 1 - IMPERVIOUS - ROOF (BF-3-1)
DMA 1 - IMPERVIOUS - DRIVEWAY (BF-3-1)
DMA 1 - IMPERVIOUS - PATIO/SIDEWALK (BF-3-1)
DMA 1 - PERVIOUS - LANDSCAPE (BF-3-1)
DMA 2 - IMPERVIOUS - DEMINIMIS
DMA 2 - PERVIOUS - LANDSCAPE
STRUCTURAL BMP -
MODULAR WETLAND UNIT
BF-3-1 MWS L-4-8
TREE WELL
6' DIAMATER CANOPY
DMA 1 - AREA TRIBUTARY TO TREE WELL
DMA 1
SECTION A-A
PLAN VIEW
NOTES:
TREE WELL WITH OPEN SPACE
•
•
•
•
A
I
4
4.9' DIA. AMEND. SOIL
3" SHREDDED HARDWOOD MULCH
ROOT
BALL
=-~-:::~--
<AMENDED < · ".> -
. SOJL oR:-ssM< : . . . . -. i:'ER · l'lANs ·: .
(1) 6' DIM.tTER CANOPY TREE
57 C.F. OF AMENDED SOIL (D=36", A=4.9')
SEE SAN 01 EGO COUNTY GREEN STREET STANDARD
DRAWING GS-1.040 FOR ADDITIONAL DETAILS
TREE SPECIES PER LANDSCAPE PLANS PER
SEPARATE PLAN
NOT TO SCALE
SAND FILTER LAYER
A
Description
Drainage Basin ID or Name
BMP ID or Name
Total Tributary Area*
Total Tributary Area*
Final Adjusted Runoff Factor'
85th Percentile Design Rainfall Depth
Design Capture Volume
85th Percentile Design Rainfall Intensity
WQ Flow Rate
Flow Rate Safety Factor
Design Flow Rate
Units
unitless
unitless
ac
sq ft
unitless
inches
cubic-feet
in/hr
CFS
unitless
CFS
Modular
Wetland
System Linear
DMAl
0477
20770
0.66
0.59
669
0.2
0.063
1.5
0.095
Modular Wetland Model unitless L-4•8*
Modular Wetland Treatment Flow Rate CFS 0.115
Is Flow-Thru BMP Adequately Sized> unitless Vi
*MWS Un it sized conservatively to account for slope area not tributary to BMP
and DeMinimus Road widening area.
0
II
0
~ ----->
--------
OMA 1-PR
DMA Type Runoff
Factor % Imper Area {ac.)
Building / Impervious 0.90 100% 5634
Driveway/ Impervious 0.90 100% 4940
Deck · Impervious 0.90 100% 1726
Landscape/ Pervious 0.30 0% 8470
Total 20770
Total
OMA 2-PR
Land sca pe/Compacted Soil 0.30 0% 9647
Road -DeMinimis 0.90 100% 463
Total 10110
Total
Total 30880
/ __ -I
.,,. ·-""7
r-~--------:-:'.O(}'/
I 0.213 ACRES l-_j:------~ ---
------------
----
0.037 ACRES
BF-3-1
MODULAR
WETLAND UNIT
MWS L-4-8
Area lac.) Summation RF
xA
0.1293
0.1134
0.0396
0.1944
0.4768
RF-
0.2215
0.0106
0.2321
RF-
0.7089
0.1164
0.1021
0.0357
0.0583
0.3 125
0.66
0.066
0.010
0.0760
0.33
--------i -~ ~--, __..,i.,.,,,==----------
,,,---10 ... 0---
...._____ ---------
-
r,-__
/ ✓-k -------
/y.,.Rii;S'
20
,/ /"
-------
0
LEGEND
--------
---------------
20 40 -----
SCALE 1 "= 20'
PREPARED BY:
60
Fusion Eng Tech
1810 Gillespie Way, Suite 207
El Cajon, CA 92020
(619) 736-2800
I XX.XX ACRES I
//,--------"\B \.
• I \ ____ /
DEVELOPED CONDmON
DRAINAGE MANAGEMENT AREA MAP
FORESTER RESIDENCE
4464 ADAMS STREET
CITY OF CARLSBAD, CALIFORNIA
MAP
1
OF
2
R:\0003\Hyd\CAD\0003$SWQMP.dwg[]0ct-07-2022:15:04
5 0 0 I "' 0 0
0 ...
ci
3i
OUTLETS TO AGUA
HEDIONDA LAGOON
PROPOSED OFFSITE IMPROVEMENTS TO ADAMS
STREET
PREPARED BY:
Fusion Eng Tech
1810 Gillespie Way, Suite 207
El Cajon, CA 92020
(619) 736-2800
DEVELOPED CONDmON
DRAINAGE MANAGEMENT AREA MAP
FORESTER RESIDENCE
4464 ADAMS STREET
CITY OF CARLSBAD, CALIFORNIA
MAP
2
OF g
0 I "' 2 ! ------------------------------------------------------------------------------ci
3i
R: \0003\Hyd\ CAD\0003$SWQMP .dwg□Jul-05-2022: 1 6:38
ATTACHMENT 1b
TABULAR SUMMARY OF DMA
-NOT INCLUDED-
SEE ATTACHMENT 1a
ATTACHMENT 1c
FORM I-7
Appendix K: Forms and Checklists
K-2 Sept. 2021
Harvest and Use Feasibility Checklist Form K-7
1. 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:______________
2. 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.
[Provide a summary of calculations here]
3. Calculate the DCV using worksheet B-2.1.
DCV = __________ (cubic feet)
3a. Is the 36 hour demand greater
than or equal to the DCV?
Yes / No
3b. Is the 36 hour demand greater than
0.25DCV but less than the full DCV?
Yes / No
3c. Is the 36 hour demand
less than 0.25DCV?
Yes
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
upsized to meet long term capture targets
while draining in longer than 36 hours.
Harvest and use is
considered to be infeasible.
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.
Note: 36-hour demand calculations are for feasibility analysis only. Once feasibility analysis is complete the
applicant may be allowed to use a different drawdown time provided they meet the 80% annual capture standard
(refer to B.4.2) and 96-hour vector control drawdown requirement.
x
x
Toilet = 1 homes x 2 residents x 9.3 gls = 18.6 gls
Landscape Irrig => ETWU = ET x [ (PF x HA)/IE] x 0.015 = 2.7 x [(0.5x17,698)/0.90] x 0.015= 398 gls
Total = 417 gls per day => 36 hour demand = 626 gls = 84 cf
x
822 See Following Sheet
x
FORESTER RESIDENCE
~ " .....__
1t 1t ~ ¢::l ¢:I
I I >
□
□
□
Appendix B: Storm Water Pollutant Control Hydrologic Calculations and Sizing Methods
B-10 February 2016
Worksheet B.2-1. DCV
Design Capture Volume Worksheet B-2.1
1 85th percentile 24-hr storm depth from Figure B.1-1 d= inches
2 Area tributary to BMP (s) A= acres
3
Area weighted runoff factor (estimate using Appendix
B.1.1 and B.2.1) C= unitless
4 Tree wells volume reduction TCV= cubic-feet
5 Rain barrels volume reduction RCV= cubic-feet
6
Calculate DCV =
(3630 x C x d x A) – TCV - RCV DCV= cubic-feet
0.59
0.709
0.474
16
0
819
Total ProjectI ~
Building / Impervious 0.90 100% 5634 0.1293 0.1164
Driveway / Impervious 0.90 100% 4940 0.1134 0.1021
Deck - Impervious 0.90 100% 1726 0.0396 0.0357
Landscape / Pervious 0.30 0% 8470 0.1944 0.0583
Total 20770 0.4768 0.3125
Total RF= 0.66
Landscape/Compacted Soil 0.30 0% 9647 0.2215 0.066
Road - DeMinimis 0.90 100% 463 0.0106 0.010
Total 10110 0.2321 0.0760
Total RF= 0.33
Total 30880 0.7089
DMA 1-PR
DMA 2-PR
DMA Type Area (ac.)Runoff
Factor % Imper Summation RF
x AArea (ac.)
ATTACHMENT 1d
FORM I-8
Categorization of Infiltration Feasibility Condition Form I-8
Part 1 - Full Infiltration Feasibility Screening Criteria
Would infiltration of the full design volume be feasible from a physical perspective without any undesirable
consequences that cannot be reasonably mitigated?
Criteria Screening Question Yes No
1
Is the estimated reliable infiltration rate below proposed facility locations
greater than 0.5 inches per hour? The response to this Screening Question
shall be based on a comprehensive evaluation of the factors presented in
Appendix C.2 and Appendix D.
Provide basis: Utilizing the Natural Resource Conservation Service (NRCS) Web Soil Survey mapping tool,
the site is underlain by soil unit MIE - Marina loamy coarse sand, 9 to 30 percent slopes. This unit is
designated as Hydrologic Soil Group B with an estimated hydraulic conductivity (Ksat): 0.57 to 1.98 inches
per hour. Three exploratory borings were advanced at site as part of the project geotechnical investigation1.
Native soils (Old Paralic Deposits) encountered in the borings vary from clayey fine-grained sand to silty
fine- to coarse-grained sand to clayey gravel and cobble in a dense to very dense condition with refusal blow
counts locally encountered. Although the soils encountered locally correlate to soil unit MIE, they are not
vertically homogenous and possess variable permeability characteristics. In addition, the site is mantled with
compacted fill soils up to 5 feet in thickness that are not conducive to infiltration. In consideration of the
variable/ interbedded soil composition and the dense to very dense condition, reliable infiltration at a rate
greater than 0.5 inches per hour is not feasible.
1 “Geotechnical Investigation and Preliminary Design Recommendations for Proposed Single-Family Residence, 4464
Adams Street, Carlsbad, California”, dated December 31, 2019, Report No. 1901-03-B-2.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide
narrative discussion of study/ data source applicability.
2
Can infiltration greater than 0.5 inches per hour be allowed without increasing
risk of geotechnical hazards (slope stability, groundwater mounding, utilities,
or other factors) that cannot be mitigated to an acceptable level? The response
to this Screening Question shall be based on a comprehensive evaluation of
the factors presented in Appendix C.2.
Provide basis: Based on our subsurface investigation1 the level building pad area of the site is mantled by up
to 5 feet of compacted fill soils with deeper fill anticipated within the existing slope overlying Old Paralic
Deposits. The Old Paralic Deposits generally consisted of dense to very dense silty sand however, silt and
clay interbeds with negligible permeability were encountered. These fine-grained interbeds will act as
aquitards concentrating stormwater at the boundary of the coarser grained material above, leading to lateral
flow and potentially daylight seepage on the slope face causing destabilization of the slope. The lower
portion of the site is in close proximity to existing offsite surface and underground improvements.
Infiltration of stormwater adjacent to existing improvements can lead to saturation/ softening of subgrade
soils leading to premature pavement failure and water intrusion into utility trenches, leading to soil piping
and potentially settlement. In addition, grading plans call for a 5 foot right-of-waydedication along Adams
Street further limiting areas suitable for infiltration type BMPs. In consideration of the variable soil
conditions, hillside nature of the project site, and proximity to existing offsite improvements, it is AGS’s
opinion that infiltration greater than 0.5 inches per hour cannot be allowed without increasing the risk of
geotechnical hazards that cannot be mitigated to an acceptable level.
1 “Geotechnical Investigation and Preliminary Design Recommendations for Proposed Single-Family Residence, 4464
Adams Street, Carlsbad, California”, dated December 31, 2019, Report No. 1901-03-B-2.
X
X
Form I-8 Page 2 of 4
Criteria Screening Question Yes No
3
Can infiltration greater than 0.5 inches per hour be allowed without increasing
risk of groundwater contamination (shallow water table, storm water
pollutants or other factors) that cannot be mitigated to an acceptable level?
The response to this Screening Question shall be based on a comprehensive
evaluation of the factors presented in Appendix C.3.
Provide basis: In consideration of the proposed land use, it is not anticipated that infiltration would pose a
significant risk provided adequate pretreatment measures are incorporated into the design and construction
of site BMPs.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide
narrative discussion of study/ data source applicability.
4
Can infiltration greater than 0.5 inches per hour be allowed without causing
potential water balance issues such as change of seasonality of ephemeral
streams or increased discharge of contaminated groundwater to surface
waters? The response to this Screening Question shall be based on a
comprehensive evaluation of the factors presented in Appendix C.3.
Provide basis: We do not anticipate water balance issues or increased discharge of contaminated water to
surface waters. However, final determination should be made by the project design engineer.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide
narrative discussion of study/ data source applicability.
Part 1
Result*
If all answers to rows 1 - 4 are “Yes” a full infiltration design is potentially feasible.
The feasibility screening category is Full Infiltration
If any answer from row 1-4 is “No”, infiltration may be possible to some extent but
would not generally be feasible or desirable to achieve a “full infiltration” design.
Proceed to Part 2
No
*To be completed using gathered site information and best professional judgment considering the definition of MEP
in the MS4 Permit. Additional testing and/or studies may be required by the City Engineer to substantiate findings
X
X
Form I-8 Page 3 of 4
Part 2 – Partial Infiltration vs. No Infiltration Feasibility Screening Criteria
Would infiltration of water in any appreciable amount be physically feasible without any negative
consequences that cannot be reasonably mitigated?
Criteria Screening Question Yes No
5
Do soil and geologic conditions allow for infiltration in any appreciable rate
or volume? The response to this Screening Question shall be based on a
comprehensive evaluation of the factors presented in Appendix C.2 and
Appendix D.
Provide basis: The coarser grained subunits within the Old Paralic Deposits possess adequate permeability
characteristics that would allow for infiltration at a rate less than 0.5 inches per hour.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide
narrative discussion of study/ data source applicability and why it was not feasible to mitigate low
infiltration rates.
6
Can Infiltration in any appreciable quantity be allowed without increasing
risk of geotechnical hazards (slope stability, groundwater mounding, utilities,
or other factors) that cannot be mitigated to an acceptable level? The
response to this Screening Question shall be based on a comprehensive
evaluation of the factors presented in Appendix C.2.
Provide basis: As discussed in our response to Criteria 2 above, due to the variable soil conditions, hillside
nature of the project site, and proximity to existing offsite improvements, it is AGS’s opinion that
infiltration in any appreciable quantity cannot be allowed without increasing the risk of geotechnical hazards
that cannot be mitigated to an acceptable level.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide
narrative discussion of study/ data source applicability and why it was not feasible to mitigate low
infiltration rates.
X
X
Form I-8 Page 4 of 4
Criteria Screening Question Yes No
7
Can Infiltration in any appreciable quantity be allowed without posing
significant risk for groundwater related concerns (shallow water table, storm
water pollutants or other factors)? The response to this Screening Question
shall be based on a comprehensive evaluation of the factors presented in
Appendix C.3.
Provide basis: In consideration of the proposed land use, it is not anticipated that infiltration would pose a
significant risk provided adequate pretreatment measures are incorporated into the design and construction
of site BMPs.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide
narrative discussion of study/ data source applicability and why it was not feasible to mitigate low
infiltration rates.
8
Can infiltration be allowed without violating downstream water rights? The
response to this Screening Question shall be based on a comprehensive
evaluation of the factors presented in Appendix C.3.
Provide basis: We do not anticipate water balance issues or increased discharge of contaminated water to
surface waters. However, final determination should be made by the project design engineer.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide
narrative discussion of study/ data source applicability and why it was not feasible to mitigate low
infiltration rates.
Part 2
Result*
If all answers from row 5-8 are yes then partial infiltration design is potentially feasible.
The feasibility screening category is Partial Infiltration.
If any answer from row 5-8 is no, then infiltration of any volume is considered to be
infeasible within the drainage area. The feasibility screening category is No Infiltration.
No
*To be completed using gathered site information and best professional judgment considering the definition of
MEP in the MS4 Permit. Additional testing and/or studies may be required by the City Engineer to substantiate
findings
X
X
ATTACHMENT 1e
POLLUTANT CONTROL BMP
DESIGN WORKSHEETS
Forester Residence
Ho me • 85th Percentile Rainfall
[ BJ Details ] I Basemap Share Print • I
◄
Legend
85th Percentile Rainfall
0 0.3 0.6mi
Contac Us
1easure
c::,
H1l.s1<re D,
\, ~-----------'
.,..
168 ft C
.:i, Sign In
Fros\4, "e
Ev s Poinr
ERE, Garm,,
t2
Building / Impervious 0.90 100% 5634 0.1293 0.1164
Driveway / Impervious 0.90 100% 4940 0.1134 0.1021
Deck - Impervious 0.90 100% 1726 0.0396 0.0357
Landscape / Pervious 0.30 0% 8470 0.1944 0.0583
Total 20770 0.4768 0.3125
Total RF= 0.66
Landscape/Compacted Soil 0.30 0% 9647 0.2215 0.066
Road - DeMinimis 0.90 100% 463 0.0106 0.010
Total 10110 0.2321 0.0760
Total RF= 0.33
Total 30880 0.7089
DMA 1-PR
DMA 2-PR
DMA Type Area (ac.)Runoff
Factor % Imper Summation RF
x AArea (ac.)
Category # Description i ii Units
1 Drainage Basin ID or Name DMA 1 DMA 2 unitless
2 85th Percentile 24-hr Storm Depth 0.59 0.59 inches
3 Impervious Surfaces Not Directed to Dispersion Area (C=0.90) 12,300 463 sq-ft
4 Semi-Pervious Surfaces Not Serving as Dispersion Area (C=0.30) 8,470 9,647 sq-ft
5 Engineered Pervious Surfaces Not Serving as Dispersion Area (C=0.10) sq-ft
6 Natural Type A Soil Not Serving as Dispersion Area (C=0.10) sq-ft
7 Natural Type B Soil Not Serving as Dispersion Area (C=0.14) sq-ft
8 Natural Type C Soil Not Serving as Dispersion Area (C=0.23) sq-ft
9 Natural Type D Soil Not Serving as Dispersion Area (C=0.30) sq-ft
10 Does Tributary Incorporate Dispersion, Tree Wells, and/ or Rain Barrels? Yes No yes/ no
11 Impervious Surfaces Directed to Dispersion Area per SD-B (Ci=0.90) sq-ft
12 Semi-Pervious Surfaces Serving as Dispersion Area per SD-B (Ci=0.30) sq-ft
13 Engineered Pervious Surfaces Serving as Dispersion Area per SD-B (Ci=0.10) sq-ft
14 Natural Type A Soil Serving as Dispersion Area per SD-B (Ci=0.10) sq-ft
15 Natural Type B Soil Serving as Dispersion Area per SD-B (Ci=0.14) sq-ft
16 Natural Type C Soil Serving as Dispersion Area per SD-B (Ci=0.23) sq-ft
17 Natural Type D Soil Serving as Dispersion Area per SD-B (Ci=0.30) sq-ft
18 Number of Tree Wells Proposed per SD-A 1 #
19 Average Mature Tree Canopy Diameter 6 ft
20 Number of Rain Barrels Proposed per SD-E #
21 Average Rain Barrel Size gal
22 Total Tributary Area 20,770 10,110 sq-ft
23 Initial Runoff Factor for Standard Drainage Areas 0.66 0.33 unitless
24 Initial Runoff Factor for Dispersed & Dispersion Areas 0.00 0.00 unitless
25 Initial Weighted Runoff Factor 0.66 0.33 unitless
26 Initial Design Capture Volume 674 164 cubic-feet
27 Total Impervious Area Dispersed to Pervious Surface 0 0 sq-ft
28 Total Pervious Dispersion Area 0 0 sq-ft
29 Ratio of Dispersed Impervious Area to Pervious Dispersion Area n/ a n/ a ratio
30 Adjustment Factor for Dispersed & Dispersion Areas 1.00 1.00 ratio
31 Runoff Factor After Dispersion Techniques 0.66 0.33 unitless
32 Design Capture Volume After Dispersion Techniques 674 164 cubic-feet
33 Total Tree Well Volume Reduction 16 0 cubic-feet
34 Total Rain Barrel Volume Reduction 0 0 cubic-feet
35 Final Adjusted Runoff Factor 0.64 0.33 unitless
36 Final Effective Tributary Area 13,293 3,336 sq-ft
37 Initial Design Capture Volume Retained by Site Design Elements 16 0 cubic-feet
38 Final Design Capture Volume Tributary to BMP 658 164 cubic-feet
False
False
Automated Worksheet B.1: Calculation of Design Capture Volume (V2.0)
Dispersion
Area, Tree
Well & Rain
Barrel Inputs
(Optional)
Standard
Drainage
Basin Inputs
Results
Tree & Barrel
Adjustments
Initial Runoff
Factor
Calculation
Dispersion
Area
Adjustments
No Warning Messages Retention Volume Provided via Tree Well
Category # Description i ii iii Units
1 Drainage Basin ID or Name DMA 1 DMA 2 DMA-TW unitless
2 85th Percentile 24-hr Storm Depth 0.59 0.59 0.59 inches
3 Impervious Surfaces Not Directed to Dispersion Area (C=0.90) 12,300 463 1,687 sq-ft
4 Semi-Pervious Surfaces Not Serving as Dispersion Area (C=0.30) 8,470 9,647 608 sq-ft
5 Engineered Pervious Surfaces Not Serving as Dispersion Area (C=0.10)sq-ft
6 Natural Type A Soil Not Serving as Dispersion Area (C=0.10)sq-ft
7 Natural Type B Soil Not Serving as Dispersion Area (C=0.14)sq-ft
8 Natural Type C Soil Not Serving as Dispersion Area (C=0.23)sq-ft
9 Natural Type D Soil Not Serving as Dispersion Area (C=0.30)sq-ft
10 Does Tributary Incorporate Dispersion, Tree Wells, and/ or Rain Barrels? Yes No Yes yes/ no
11 Impervious Surfaces Directed to Dispersion Area per SD-B (Ci=0.90)sq-ft
12 Semi-Pervious Surfaces Serving as Dispersion Area per SD-B (Ci=0.30)sq-ft
13 Engineered Pervious Surfaces Serving as Dispersion Area per SD-B (Ci=0.10)sq-ft
14 Natural Type A SoilServing as Dispersion Area per SD-B (Ci=0.10)sq-ft
15 Natural Type B SoilServing as Dispersion Area per SD-B (Ci=0.14)sq-ft
16 Natural Type C Soil Serving as Dispersion Area per SD-B (Ci=0.23)sq-ft
17 Natural Type D Soil Serving as Dispersion Area per SD-B (Ci=0.30)sq-ft
18 Number of Tree Wells Proposed per SD-A 1 1 #
19 Average Mature Tree Canopy Diameter 6 6 ft
20 Number of Rain Barrels Proposed per SD-E #
21 Average Rain Barrel Size gal
22 Total Tributary Area 20,770 10,110 2,295 sq-ft
23 Initial Runoff Factor for Standard Drainage Areas 0.66 0.33 0.74 unitless
24 Initial Runoff Factor for Dispersed & Dispersion Areas 0.00 0.00 0.00 unitless
25 Initial Weighted Runoff Factor 0.66 0.33 0.74 unitless
26 Initial Design Capture Volume 674 164 83 cubic-feet
27 Total Impervious Area Dispersed to Pervious Surface 0 0 0 sq-ft
28 Total Pervious Dispersion Area 0 0 0 sq-ft
29 Ratio of Dispersed Impervious Area to Pervious Dispersion Area n/a n/ a n/ a ratio
30 Adjustment Factor for Dispersed & Dispersion Areas 1.00 1.00 1.00 ratio
31 Runoff Factor After Dispersion Techniques 0.66 0.33 0.74 unitless
32 Design Capture Volume After Dispersion Techniques 674 164 83 cubic-feet
33 Total Tree Well Volume Reduction 16 0 16 cubic-feet
34 Total Rain Barrel Volume Reduction 0 0 0 cubic-feet
35 Final Adjusted Runoff Factor 0.64 0.33 0.60 unitless
36 Final Effective Tributary Area 13,293 3,336 1,377 sq-ft
37 Initial Design Capture Volume Retained by Site Design Elements 16 0 16 cubic-feet
38 Final Design Capture Volume Tributary to BMP 658 164 67 cubic-feet
False
False
Automated Worksheet B.1: Calculation of Design Capture Volume (V2.0)
Dispersion
Area, Tree Well
& Rain Barrel
Inputs
(Optional)
Standard
Drainage Basin
Inputs
Results
Tree & Barrel
Adjustments
Initial Runoff
Factor
Calculation
Dispersion
Area
Adjustments
No Warning Messages
Retention Volume Provided via Tree Well
Separate calculation for area tributary to Tree Well
Category # Description i ii Units
1 Drainage Basin ID or Name DMA 1 DMA 2 unitless
2 85th Percentile Rainfall Depth 0.59 0.59 inches
3 Predominant NRCS Soil Type Within BMP Location B B unitless
4 Is proposed BMP location Restricted or Unrestricted for Infiltration Activities? Restricted Restricted unitless
5 Nature of Restriction Slopes Slopes unitless
6 Do Minimum Retention Requirements Apply to this Project? Yes Yes yes/ no
7 Are Habitable Structures Greater than 9 Stories Proposed? No No yes/ no
8 Has Geotechnical Engineer Performed an Infiltration Analysis?No No yes/ no
9 Design Infiltration Rate Recommended by Geotechnical Engineer in/ hr
10 Design Infiltration Rate Used To Determine Retention Requirements 0.000 0.000 in/ hr
11 Percent of Average Annual Runoff that Must be Retained within DMA 4.5% 4.5% percentage
12 Fraction of DCV Requiring Retention 0.02 0.02 ratio
13 Required Retention Volume 13 3 cubic-feet
False
False
Automated Worksheet B.2: Retention Requirements (V2.0)
Advanced
Analysis
Basic Analysis
Result
No Warning Messages Retention Volume Required
Appendix B: Storm Water Pollutant Control Hydrologic Calculations and Sizing Methods
B-36 February 2016
B.6.3 Sizing Flow-Thru Treatment Control BMPs: Use for Sizing
Proprietary Biofiltration BMP
Flow-thru treatment control BMPs shall be sized to filter or treat the maximum flow rate of runoff
produced from a rainfall intensity of 0.2 inch of rainfall per hour, for each hour of every storm event.
The required flow-thru treatment rate should be adjusted for the portion of the DCV already retained
or biofiltered onsite as described in Worksheet B.6-1. The following hydrologic method shall be used
to calculate the flow rate to be filtered or treated: 𝑄=𝐶× 𝑖× 𝐴
Where:
Q = Design flow rate in cubic feet per second
C = Runoff factor, area-weighted estimate using Table B.1-1.
i = Rainfall intensity of 0.2 in/hr.
A = Tributary area (acres) which includes the total area draining to the BMP, including any
offsite or onsite areas that comingle with project runoff and drain to the BMP. Refer to Section
3.3.3 for additional guidance. Street projects consult Section 1.4.2.
Worksheet B.6-1: Flow-Thru Design Flows
Flow-thru Design Flows Worksheet B.6-1
1 DCV DCV cubic-feet
2 DCV retained DCVretained cubic-feet
3 DCV biofiltered DCVbiofiltered cubic-feet
4 DCV requiring flow-thru
(Line 1 – Line 2 – 0.67xLine 3) DCVflow-thru cubic-feet
5 Adjustment factor (Line 4 / Line 1)* AF= unitless
6 Design rainfall intensity i= 0.20 in/hr
7 Area tributary to BMP (s) A= acres
8 Area-weighted runoff factor (estimate using
Appendix B.2) C= unitless
9 Calculate Flow Rate = AF x (C x i x A) Q= cfs
*Adjustment factor shall be estimated considering only retention and biofiltration BMPs located upstream of
flow-thru BMPs. That is, if the flow-thru BMP is upstream of the project's retention and biofiltration BMPs
then the flow-thru BMP shall be sized using an adjustment factor of 1.
669
0
0
669
1.0
0.478
0.66
0.063
Q treat = 1.5 x Q = 0.095 cfs
USE MODULAR WETLAND
UNIT MODLE L-4-8,
CAPACITY = 0.115 CFS
PERFORMANCE STANDARD CALCULATION
-
Description Units
Modular
Wetland
System Linear
Drainage Basin ID or Name unitless DMA 1
BMP ID or Name unitless BF-3-1
Total Tributary Area*ac 0.477
Total Tributary Area*sq ft 20770
Final Adjusted Runoff Factor*unitless 0.66
85th Percentile Design Rainfall Depth inches 0.59
Design Capture Volume cubic-feet 669
85th Percentile Design Rainfall Intensity in/hr 0.2
WQ Flow Rate CFS 0.063
Flow Rate Safety Factor unitless 1.5
Design Flow Rate CFS 0.095
Modular Wetland Model unitless L-4-8*
Modular Wetland Treatment Flow Rate CFS 0.115
Is Flow-Thru BMP Adequately Sized?unitless Yes
*MWS Unit sized conservatively to account for slope area not tributary to BMP
and DeMinimus Road widening area.
ATTACHMENT 1E
MWS-L-4-8 SELECTED
'1 MWS LINEAR 2.0 HGL S 'IZING CALCULATION S ~
SHALLOW MODELS HIGH CAPACITY MODELS
WETU.NE> LOll:DING
3,3 1[• PiEiRMJTEII: RA.TE 1.4 1.5 l .6 1.7 1.8 l.9 2.0 2.1 2.2 2,3 2.4 2.5 2.6 2.7 2..8 2.9 3.0 3.1 3.2 3.5 3.6 3.65 3.70 3.75 3.80 3.85 3.90 3.95
MWS MODEL SIZE liiNG11f GPMfSF
MWS-L-4-4 6.70 1..0 0_022 0_023 0.025 0_026 0.028 0.029 0_031 0.032 o_o34 0_035 o_o37 0_038 0.040 0_042 0_043 0.045 0_046 0_0411 01)49 0_051 0_054 0.055 o_o,;i; 0_057 0_058 0,058 0_059 0_060 0.061
MWS-L-3-6 10.06 LO 0_032 0_035 0.037 0.039 0_042 0.044 0_046 0.0411 0.051 0_053 0_05s 0_058 0.060 0.062 0_065 0.067 0_069 0.072 0.074 0_076 -'h o_os1 0.083 0_084 0.085 0_087 0_088 0.089 0.090 0.091
MWS-L-4-6 9.30 LO 0_030 0_032 0.034 0_036 0_038 0_041 0_043 0.045 0_047 0_049-0_()51 0_053 0.055 Q_058 0_060 0.062 0_064 0.066 0_068 0_070 ii&,; 0_075 Fl Q_078 0.079 0_080 0_081 0.082 0_083 0.084
l····3 ---MWS-L-4-8 l t::.SO LO 01)48 0_051 0.054 0_05s 0_061 0_065 0_068 0.071 oms 0_078 0_082 OJJ85 0.088 0.092 0_095 0.099-o_102 0.105 0_109 0_112 ............ to-119 0.122 0_124 0.126 0.127 0_129 0.131 0_132 0.134 ----11.:;-,=-
MWS-L-4-13 18.<0 LO 0_059 0_063 0.068 o_on 0_076 o_oao 0:084 0.089-0_093 0_097 0.101 0_106 0.110 0_114 0_118 0.122 0_127 0.131 0_135 0_139 0_148 0.152 0_154 0.156 0_158 0_160 0.163 0_165 0.167
MWS-L-4-15 22.<0 LO o_on o_on 0.082 0.087 0.093 oms 0_103 0.108 0.113 0_118 OJ.23 0_129 0.134 0_139 0_144 0.149-0_154 0.159 0_165 0_170 0_180 0.185 0_188 0.19-0 0_193 0_195 0.198 0_200 0.2°'3
MWS-L-4-17 26.<0 1..0 0_085 0_091 0.097 0_103 Q109 0_115 0_121 0.127 0_133 0_139 0_145 Q151 0.15S 0_164 0_170 0.176 0_182 0.188 0_19-4 0_200 0_212 0.218 0221 0.224 0-227 Q230 0.233 0-236 0.239
MWS-L-4-19 30 . .::.0 LO 01J91l 0_105 0.112 0_119 0.126 0.133 0_140 0.147 0.153 0_160 0.167 0_174 0.181 0.188 0_195 0.202 0209 0.216 0."223 0_230 •• 0_244 0.251 0255 0.25S 0.262 0_265 0.269 0.272 0.276
MWS-L-4-21 34.<0 LO 0.111 0_118 0.126 0.134 0_142 0.150 0_158 0.166 0.174 0_182 0.189 0_197 0.205 0.213 0_221 0.229 0237 0.245 0.253 0_261 0_276 0.284 0288 0_292 0.296 0-300 0.304 0308 03 12
MWS-L-6-8 18.80 LO 0.060 0_065 0.069 0.073 0_07S 0_082 0_086 0.091 0.095 0_099 0_104 0_108 0.112 0_116 0_121 0.125 0_129 0.134 0_138 0_142 } .... , 0_151 0.155 0_157 0.160 0_162 0_164 0.166 0_168 0.170
MWS-L-8--8 29.60 LO 0_095 0_102 0.109 0.115 0.122 0_129 0_136 0.143 0.149 0_156 0 . .163 0_170 0.177 0_183 0_190 0.197 0204 0.211 0-217 0_224 llta 0_238 0.245 0-248 0.251 0_255 0-258 0.262 0-265 0.268
MWS-L-8-12 4-!;_d.0 LO 0_143 0_153 0.163 0_173 0_183 0_19-4 0_204 0.214 0_224 0-234 0245 Q255 0.265 0-275 0-285 0.2.96 0306 0.316 0-326 0-336 --0-357 0.367 03n 0.3n 0-382 0_387 0392 0397 0.402
MWS-L-8-16 59.20 LO 0.190 0-204 0.217 0.231 0_245 0.258 0_272 0.285 0.299 0_312 0326 0_340 0.353 0-367 0-300 0.394 0_408 0.421 0.435 0_448 I,_ 0-476 0.489-0_496 0.503 0.509 0_516 0.523 0.530 0.537
MWS-l-8-20 7111.00 LO 0-238 0_255 0.272 0_2S9 0_306 0_323 0-340 0.357 0374 0_391 0.408 0-425 0.442 0_459 0-476 0.493 0.509 0.526 0.543 0_560 fA¥t· 0-594 0.611 0_620 0.62S 0_637 0_645 0.654 0_662 0.671
MWS-L-10-20 or 0.326 83.80 LO 0_285 0_306 0346 0_367 0-387 0-408 0.428 0.448 0_469 0-4S9 0-509 0.530 0-550 0_571 0.591 0_611 0.632 0_652 . .,.E 0.713 0.734 0_744 0.754 0.764 o_n4 0.785 0_795 0.805 MWS-L-8-24
~•••4medHiuire 14,SO 1-0 ...... 1>.0,:1: o.~4 0.0.!>8 O.OE-1 0.1).5:, D..062-0,071 ok01, 0.073-._.., 0..083 a.oa,3 0.1.r:'Z ._.., G.05':I 0~1ilZ 0.10<) 0.1-09 1)..112 II 0.119 0.1ll 0.12-'1
STANDARD DETAIL
STORMWATER BIOFILTRATION SYSTEM
MWS-L-4-6-5'-5"-V-HC
SITE SPECIFIC DATA
INTERNAL BYPASS DISCLOSURE:
PLAN VIEW
ELEVATION VIEW
RIGHT END VIEW
LEFT END VIEW
GENERAL NOTES
INSTALLATION NOTES
PROJECT NUMBER 14264
PROJECT NAME FORESTER RESIDENCE
PROJECT LOCATION CARLSBAD, CA
STRUCTURE ID BF-3-1
TREATMENT REQUIRED
VOLUME BASED {CF) FLOW BASED {CFS)
N/A 0.078
TREATMENT HGL AVAILABLE (FT) N/K
PEAK BYPASS REQUIRED {CFS) -IF APPLICABLE 1.85
PIPE DATA I.£ MATERIAL DIAMETER
INLET PIPE 1 76.33 HOPE 8"
INLET PIPE 2 N/A N/A N/A
OUTLET PIPE 75.00 HOPE 8"
PRETREATMENT BIOFILTRA TION DISCHARGE
RIM ELEVATION 80.50 80.50 80.50
SURFACE LOAD PEDESTRIAN N/A PEDESTRIAN
FRAME & COVER 24" X 42" OPEN PLANTER N/A
WETLANDMEDIA VOLUME (CY) 2.00
ORIFICE SIZE {DIA. INCHES) ¢1.24"
NOTES: PRELIMINARY NOT FOR CONSTRUCTION.
1. CONTRACTOR TO PROVIDE ALL LABOR, EQUIPMENT, MATERIALS AND
INCIDENTALS REQUIRED TO OFFLOAD AND INSTALL THE SYSTEM AND
APPURTENANCES IN ACCORDANCE WITH THIS DRAWING AND THE
MANUFACTURERS' SPECIFICATIONS, UNLESS OTHERWISE STATED IN
MANUFACTURER'S CONTRACT.
2. UNIT MUST BE INSTALLED ON LEVEL BASE. MANUFACTURER
RECOMMENDS A MINIMUM 6" LEVEL ROCK BASE UNLESS SPECIFIED BY
THE PROJECT ENGINEER. CONTRACTOR IS RESPONSIBLE FOR VERIFYING
PROJECT ENGINEER's RECOMMENDED BASE SPECIFICATIONS.
4. CONTRACTOR TO SUPPLY AND INSTALL ALL EXTERNAL CONNECTING
PIPES. ALL PIPES MUST BE FLUSH WITH INSIDE SURFACE OF
CONCRETE (PIPES CANNOT INTRUDE BEYOND FLUSH). INVERT OF
OUTFLOW PIPE MUST BE FLUSH WITH DISCHARGE CHAMBER FLOOR.
ALL PIPES SHALL BE SEALED WATERTIGHT PER MANUFACTURER'S
STANDARD CONNECTION DETAIL.
5. CONTRACTOR RESPONSIBLE FOR INSTALLATION OF ALL PIPES, RISERS,
MANHOLES, AND HATCHES. CONTRACTOR TO GROUT ALL MANHOLES AND
HATCHES TO MATCH FINISHED SURFACE UNLESS SPECIFIED OTHERWISE.
6. VEGETATION SUPPLIED AND INSTALLED BY OTHERS. ALL UNITS WITH
VEGETATION MUST HAVE DRIP OR SPRAY IRRIGATION SUPPLIED AND
INSTALLED BY OTHERS.
7. CONTRACTOR RESPONSIBLE FOR CONTACTING BIO CLEAN FOR
ACTIVATION OF UNIT. MANUFACTURER'S WARRANTY IS VOID WITHOUT
PROPER ACTIVATION BY A BIO CLEAN REPRESENTATIVE.
1. MANUFACTURER TO PROVIDE ALL MATERIALS UNLESS OTHERWISE NOTED.
2. ALL DIMENSIONS, ELEVATIONS, SPECIFICATIONS AND CAPACITIES ARE SUBJECT TO
CHANGE. FOR PROJECT SPECIFIC DRAWINGS DETAILING EXACT DIMENSIONS, WEIGHTS
AND ACCESSORIES PLEASE CONTACT BIO CLEAN.
~___,.,...,,__--~~ ~ PATENTED
DRAIN DOWN LINE
~
PRE-FILTER-+--4a.;;;;;;.;.b--=ifal±-t:l"="i
CARTRIDGE
C/L
78.94
PEAK HGL
PERIMETER
VOID AREA
80.50
RIM/FG
FLOW CONTROL
RISER
75.00
IE OUT
6"_J L4·-o·__J L6-
~5•-o· ~
THE DESIGN AND CAPACITY OF THE PEAK CONVEYANCE METHOD TO BE REVIEWED
AND APPROVED BY THE ENGINEER OF RECORD. HGL(S) AT PEAK FLOW SHALL BE
ASSESSED TO ENSURE NO UPSTREAM FLOODING. PEAK HGL AND BYPASS
CAPACITY SHOWN ON DRAWING ARE USED FOR GUIDANCE ONLY.
i.£GETATION
• PLANT ~
5TABLl~z~~:~1,~~~\~:Jt-,;;~::::;;=rr-7 ; l
m ~~ ~ .1
~'. ~
ir
f':
t::
6"_J .----6'-o"----in
1----------7'-0"------.
• l.c')
TREATMENT FLOW (CFS)
OPERATING HEAD {FT)
PRETREATMENT LOADING RATE {GPM/SF)
WETLAND MEDIA LOADING RATE (GPM/SF)
~' " 0 D U 1., ,A R ~ETLAND5 THE INFORIIATION CONTAINED IN THIS OOCUMENT IS THE SOLE PROPERTY OF FORT£RRA ANO ITS COMPANIES. THIS OOCUMENT. 7l: :t::0:/,/fi =-~~ ~4%.::f o,, NOR ANY PA/ff THEREOF. A44Y BE USED, REPRODUCED OR l,f(){)(flED
PROPRIETARY AND CONFIDENTIAL:
Bio ~Clean
7.67'"11': =14-1EA1ED F1J/IE1(//( PA1ENIS OR IN ANY A44NN£R WITH OUT THE WRITTEN CONSENT OF FORT£RRA.
0/HER PA1ENIS -AFortemCom
0.078
3.7
2.7
1.0
ATTACHMENT 2
BACKUP FOR
HYDROMODIFICATION CONTROL
MEASURES
This Attachment 2 is not applicable to this site since it is HMP
Exempt beacuse: 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.
This project discharges directly to Agua Hedionda Lagoon.
Please refer to Hydromodification Exemption Analysis for
Select Carlsbad Watersheds, prepared by Chang Consul-
tants, dated September 17, 2015.
ATTACHMENT 2
BACKUP FOR PDP HYDROMODIFICATION CONTROL MEASURES
[This is the cover sheet for Attachment 2.]
Indicate which Items are Included behind this cover sheet:
Attachment
Sequence
Contents Checklist
Attachment 2a Hydromodification Management Exhibit
(Required)
Included
See Hydromodification Management
Exhibit Checklist on the back of this
Attachment cover sheet.
Attachment 2b Management of Critical Coarse Sediment
Yield Areas (WMAA Exhibit is required,
additional analyses are optional)
See Section 6.2 of the BMP Design
Manual.
Exhibit showing project drainage
boundaries marked on WMAA
Critical Coarse Sediment Yield Area
Map (Required)
Optional analyses for Critical Coarse
Sediment Yield Area Determination
6.2.1 Verification of Geomorphic
Landscape Units Onsite
6.2.2 Downstream Systems
Sensitivity to Coarse Sediment
6.2.3 Optional Additional Analysis of
Potential Critical Coarse Sediment
Yield Areas Onsite
Attachment 2c Geomorphic Assessment of Receiving
Channels (Optional)
See Section 6.3.4 of the BMP Design
Manual.
Not performed
Included
Attachment 2d Flow Control Facility Design and
Structural BMP Drawdown Calculations
(Required)
See Chapter 6 and Appendix G of the
BMP Design Manual
IncludedN/
A
Use this checklist to ensure the required information has been included on the Hydromodification
Management Exhibit:
The Hydromodification Management Exhibit must identify:
Underlying hydrologic soil group
Approximate depth to groundwater
Existing natural hydrologic features (watercourses, seeps, springs, wetlands)
Critical coarse sediment yield areas to be protected (if present)
Existing topography
Existing and proposed site drainage network and connections to drainage offsite
Proposed grading
Proposed impervious features
Proposed design features and surface treatments used to minimize imperviousness
Point(s) of Compliance (POC) for Hydromodification Management
Existing and proposed drainage boundary and drainage area to each POC (when necessary, create
separate exhibits for pre-development and post-project conditions)
Structural BMPs for hydromodification management (identify location, type of BMP, and size/detail)
N/
A
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ATTACHMENT 3
STRUCTURAL BMP
MAINTENANCE INFORMATION
ATTACHMENT 3
Structural BMP Maintenance Information
Use this checklist to ensure the required information has been included in the Structural BMP
Maintenance Information Attachment:
Preliminary Design / Planning / CEQA level submittal:
Attachment 3 must identify:
Typical maintenance indicators and actions for proposed structural BMP(s) based on
Section 7.7 of the BMP Design Manual
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
Maintenance Guidelines for
Modular Wetland System -Linear
Maintenance Summary
1-
MO DUL Af'l. WETLANDS
o Remove Trash from Screening Device -average maintenance interval is 6 to 12 months.
■ (5 minute average service time).
o Remove Sediment from Separation Chamber -average maintenance interval is 12 to 24 months.
■ ( 10 minute average service time).
o Replace Cartridge Filter Media -average maintenance interval 12 to 24 months.
■ ( 10-15 minute per cartridge average service time).
o Replace Drain Down Filter Media -average maintenance interval is 12 to 24 months.
■ (5 minute average service time).
o Trim Vegetation -average maintenance interval is 6 to 12 months.
■ ( Service time varies).
System Diagram
Inflow Pipe
(optional)
Access to screening device, separation
chamber and cartridge filter
Biofiltration Chamber
www.modularwetlands.com
Access to drain
down filter
i_
M ODULA P. WETLANDS
Maintenance Procedures
Screening Device
1. Remove grate or manhole cover to gain access to the screening device in the Pre-
Treatment Chamber. Vault type units do not have screening device. Maintenance
can be performed without entry.
2. Remove all pollutants collected by the screening device. Removal can be done
manually or with the use of a vacuum truck. The hose of the vacuum truck will not
damage the screening device.
3. Screening device can easily be removed from the Pre-Treatment Chamber to gain
access to separation chamber and media filters below. Replace grate or manhole
cover when completed.
Separation Chamber
1. Perform maintenance procedures of screening device listed above before
maintaining the separation chamber.
2. With a pressure washer spray down pollutants accumulated on walls and cartridge
filters.
3. Vacuum out Separation Chamber and remove all accumulated pollutants. Replace
screening device, grate or manhole cover when completed.
Cartridge Filters
1. Perform maintenance procedures on screening device and separation chamber
before maintaining cartridge filters.
2. Enter separation chamber.
3. Unscrew the two bolts holding the lid on each cartridge filter and remove lid.
4. Remove each of 4 to 8 media cages holding the media in place.
5. Spray down the cartridge filter to remove any accumulated pollutants.
6. Vacuum out old media and accumulated pollutants.
7. Reinstall media cages and fill with new media from manufacturer or outside
supplier. Manufacturer will provide specification of media and sources to purchase.
8. Replace the lid and tighten down bolts. Replace screening device, grate or
manhole cover when completed.
Drain Down Filter
1. Remove hatch or manhole cover over discharge chamber and enter chamber.
2. Unlock and lift drain down filter housing and remove old media block. Replace with
new media block. Lower drain down filter housing and lock into place.
3. Exit chamber and replace hatch or manhole cover.
www.modularwetlands.com
1-
MO DUL Af'l. WETLANDS
Maintenance Notes
1. Following maintenance and/or inspection, it is recommended the maintenance
operator prepare a maintenance/inspection record. The record should include any
maintenance activities performed, amount and description of debris collected, and
condition of the system and its various filter mechanisms.
2. The owner should keep maintenance/inspection record(s) for a minimum of five
years from the date of maintenance. These records should be made available to
the governing municipality for inspection upon request at any time.
3. Transport all debris, trash, organics and sediments to approved facility for disposal
in accordance with local and state requirements.
4. Entry into chambers may requ ire confined space training based on state and local
regulations.
5. No fertilizer shall be used in the Biofiltration Chamber.
6. Irrigation should be provided as recommended by manufacturer and/or landscape
architect. Amount of irrigation required is dependent on plant species. Some plants
may require irrigation.
www.modularwetlands.com
Maintenance Procedure Illustration
Screening Device
The screening device is located directly
under the manhole or grate over the
Pre-Treatment Chamber. It's mounted
directly underneath for easy access
and cleaning. Device can be cleaned by
hand or with a vacuum truck.
Separation Chamber
The separation chamber is located
directly beneath the screening device.
It can be quickly cleaned using a
vacuum truck or by hand. A pressure
washer is useful to assist in the
cleaning process.
www.modularwetlands.com
MODULAR
WETLANDS
Cartridge Filters
The cartridge filters are located in the
Pre-Treatment chamber connected to
the wall adjacent to the biofiltration
chamber. The cartridges have
removable tops to access the
individual media filters. Once the
cartridge is open media can be
easily removed and replaced by hand
or a vacuum truck.
Drain Down Filter
The drain down filter is located in the
Discharge Chamber. The drain filter
unlocks from the wall mount and hinges
up. Remove filter block and replace with
new block.
www.modularwetlands.com
MODULAR
WETLANDS
Trim Vegetation
Vegetation should be maintained in the
same manner as surrounding vegetation
and trimmed as needed. No fertilizer shall
be used on the plants. Irrigation
per the recommendation of the
manufacturer and or landscape
architect. Different types of vegetation
requires different amounts of
irrigation.
www.modularwetlands.com
MODULAR
WETLANDS
Inspection Form
Modular Wetland System, Inc.
P. 760.433-7640
F. 760-433-3176
E. lnfo@modularwetlands.com
www.modularwetlands.com
MODULAR
WETLANDS
Inspection Report
Modular Wetlands System
l:_
WETLANDS
Project Name
Project Address ------------------------------------------(city) (z;p Code)
Owner I Management Company ___________________________________ _
Contact -----------------------Phone (
Inspector Name ___________________ _ Date Time
For Office Use Only
(Reviewed By)
(Date)
Offioo personnel 10 complete sootion to
the left.
AM /PM
Type of Inspection O Routine 0 FollowUp 0 Complaint 0 Storm Storm Event in Last 72-hours? 0 No O Yes
Weather Condition ___________________ Additional Notes
Inspection Checklist
Modular Wetland System Type (Curb, Grate or UG Vault): Size (22', 14' or etc.):
Structural Integrity: Yes No Comments
Damage to pre-treatment access cover (manhole cover/grate) or cannot be opened using normal lifting
pressure?
Damage to discharge chamber access cover (manhole cover/grate) or cannot be opened using normal lifting
pressure?
Does the MWS unit show signs of structural deterioration (cracks in the wall, damage lo frame)?
Is the inlet/outlet pipe or drain down pipe damaged or otherwise not functioning properly?
Working Condition:
Is there evidence of illicit discharge or excessive oil, grease, or other automobile fluids entering and clogging th1
unit?
Is there standing water in inappropriate areas after a dry period?
Is the filter insert (if applicable) at capacity and/or is there an accumulation of debris/trash on the shelf system?
Does the depth of sediment/trash/debris suggest a blockage of the inflow pipe, bypass or cartridge filter? If yes IOeplh:
specify which one in the comments section. Note depth of accumulation in in pre-treatment chamber.
Does the cartridge filter media need replacement in pre-treatment chamber and/or discharge chamber? Chamber.
Any signs of improper functioning in the discharge chamber? Note issues in comments section.
Other Inspection Items:
Is there an accumulation of sediment/trash/debris in the wetland media (if applicable)?
ts it evident that the plants are alive and healthy (if applicable)? Please note Plant Information below.
Is there a septic or foul odor coming from inside the system?
Waste: Yes No Recommended Maintenance Plant Information
Sediment / Silt / Clay No Cleaning Needed Damaae to Plants
Trash/ Bags / Bottles Schedule Maintenance as Planned Plant Replacement
Green Waste I Leaves / Foliage Needs Immediate Maintenance Plant Trimmina
Additional Notes:
2972 San Luis Rey Road, Oceanside, CA 92058 P (760) 433-7640 F (760) 433-3176
,. :,a l
-~ . -'
:j :·:,
~·
Maintenance Report
• 4 P' ~
,ef"'.~
-.:·~~'~ --r.
Modular Wetland System, Inc.
P. 760.433-7640
F. 760-433-3176
E. lnfo@modularwetlands.com
www.modularwetlands.com
~
MODULAR
WETLANDS
,·
\ • \I ' . \ •• i
CLEAN.
ENVlltONME.NTAL $£1tVfC.ES, tNC
Cleaning and Maintenance Report
Modular Wetlands System
Project Name --------------------------------------For Office Use Only
ProjectAddress --------------------------------------cc11yJ (Zip Code) (Reviewed B:,1)
Owner I Management Company---------------------------------
Contact ---------------------
Inspector Name _________________ _
Type of Inspection D Routine □ FollowUp D Complaint
Weather Condition
Site GPS Coordinates Manufacturer / Trash
Map# of Insert Description / Sizing Accumulation
Lat: MWS
Catch Basins
Long:
MWS
Sedimentation
Basin
Media Filter
Condition
Plant Condition
Drain Down Media
Condition
Discharge Chamber
Condition
Drain Down Pipe --Condition
Inlet and Outlet
Pipe Condition
Comments:
Phone (
Date
Ostorm
Additional Notes
Foliage Sediment
Accumulation Accumulation
Time
11ua,e1
Office pe,sonnel to complete section to
the left.
AM /PM ------
Storm Event in Last 72-hours? D No D Yes
Condition of Media Operational Per
Total Debris 25/50/75/100 Manufactures'
Accumulation (will be changed Specifications
@75%) (If not, why?)
2972 San Luis Rey Road, Oceanside, CA 92058 P. 760.433.7640 F. 760.433.3176
July 2017
GENERAL USE LEVEL DESIGNATION FOR BASIC, ENHANCED, AND
PHOSPHORUS TREATMENT
For the
MWS-Linear Modular Wetland
Based on Modular Wetland Systems, Inc. application submissions, including the Technical
Evaluation Report, dated April 1, 2014, Ecology hereby issues the following use level
designation:
1. General use level designation (GULD) for the MWS-Linear Modular Wetland Stormwater
Treatment System for Basic treatment
Sized at a hydraulic loading rate of 1 gallon per minute (gpm) per square foot (sq ft) of
wetland cell surface area. For moderate pollutant loading rates (low to medium density
residential basins), size the Prefilters at 3.0 gpm/sq ft of cartridge surface area. For high
loading rates (commercial and industrial basins), size the Prefilters at 2.1 gpm/sq ft of
cartridge surface area.
2. General use level designation (GULD) for the MWS-Linear Modular Wetland Stormwater
Treatment System for Phosphorus treatment
Sized at a hydraulic loading rate of 1 gallon per minute (gpm) per square foot (sq ft) of
wetland cell surface area. For moderate pollutant loading rates (low to medium density
residential basins), size the Prefilters at 3.0 gpm/sq ft of cartridge surface area. For high
loading rates (commercial and industrial basins), size the Prefilters at 2.1 gpm/sq ft of
cartridge surface area.
3. General use level designation (GULD) for the MWS-Linear Modular Wetland Stormwater
Treatment System for Enhanced treatment
Sized at a hydraulic loading rate of 1 gallon per minute (gpm) per square foot (sq ft) of
wetland cell surface area. For moderate pollutant loading rates (low to medium density
residential basins), size the Prefilters at 3.0 gpm/sq ft of cartridge surface area. For high
loading rates (commercial and industrial basins), size the Prefilters at 2.1 gpm/sq ft of
cartridge surface area.
WAS I IN 6 T ON ST AT E 0 E P A R T M I N l O F
E C O L O G Y
Ecology's Decision:
•
•
•
4. Ecology approves the MWS - Linear Modular Wetland Stormwater Treatment System units
for Basic, Phosphorus, and Enhanced treatment at the hydraulic loading rate listed above.
Designers shall calculate the water quality design flow rates using the following procedures:
Western Washington: For treatment installed upstream of detention or retention, the
water quality design flow rate is the peak 15-minute flow rate as calculated using the
latest version of the Western Washington Hydrology Model or other Ecology-approved
continuous runoff model.
Eastern Washington: For treatment installed upstream of detention or retention, the
water quality design flow rate is the peak 15-minute flow rate as calculated using one of
the three methods described in Chapter 2.2.5 of the Stormwater Management Manual
for Eastern Washington (SWMMEW) or local manual.
Entire State: For treatment installed downstream of detention, the water quality design
flow rate is the full 2-year release rate of the detention facility.
5. These use level designations have no expiration date but may be revoked or amended by
Ecology, and are subject to the conditions specified below.
Applicants shall comply with the following conditions:
1. Design, assemble, install, operate, and maintain the MWS Linear Modular Wetland
Stormwater Treatment System units, in accordance with Modular Wetland Systems, Inc.
applicable manuals and documents and the Ecology Decision.
2. Each site plan must undergo Modular Wetland Systems, Inc. review and approval before
site installation. This ensures that site grading and slope are appropriate for use of a MWS
Linear Modular Wetland Stormwater Treatment System unit.
3. MWS Linear Modular Wetland Stormwater Treatment System media shall conform to the
specifications submitted to, and approved by, Ecology.
4. The applicant tested the MWS Linear Modular Wetland Stormwater Treatment System
with an external bypass weir. This weir limited the depth of water flowing through the
media, and therefore the active treatment area, to below the root zone of the plants. This
GULD applies to MWS Linear Modular Wetland Stormwater Treatment Systems whether
plants are included in the final product or not.
5. Maintenance: The required maintenance interval for stormwater treatment devices is often
dependent upon the degree of pollutant loading from a particular drainage basin. Therefore,
particular model/size of manufactured filter treatment device.
Typically, Modular Wetland Systems, Inc. designs MWS - Linear Modular Wetland
systems for a target prefilter media life of 6 to 12 months.
Indications of the need for maintenance include effluent flow decreasing to below the
design flow rate or decrease in treatment below required levels.
Owners/operators must inspect MWS - Linear Modular Wetland systems for a minimum
of twelve months from the start of post-construction operation to determine site-specific
•
•
•
Ecology's Conditions of Use:
Ecology does not endorse or recommend a "one size fits all" maintenance cycle for a
•
•
•
maintenance schedules and requirements. You must conduct inspections monthly during
the wet season, and every other month during the dry season. (According to the
SWMMWW, the wet season in western Washington is October 1 to April 30. According
to SWMMEW, the wet season in eastern Washington is October 1 to June 30). After the
first year of operation, owners/operators must conduct inspections based on the findings
during the first year of inspections.
methods capable of determining either a decrease in treated effluent flowrate and/or a
decrease in pollutant removal ability.
When inspections are performed, the following findings typically serve as maintenance
triggers:
Standing water remains in the vault between rain events, or
Bypass occurs during storms smaller than the design storm.
If excessive floatables (trash and debris) are present (but no standing water or
excessive sedimentation), perform a minor maintenance consisting of gross solids
removal, not prefilter media replacement.
Additional data collection will be used to create a correlation between pretreatment
chamber sediment depth and pre-filter clogging (see Issues to be Addressed by the
Company section below)
6. Discharges from the MWS - Linear Modular Wetland Stormwater Treatment System units
shall not cause or contribute to water quality standards violations in receiving waters.
Applicant:Modular Wetland Systems, Inc.
Applicant's Address:PO. Box 869
Oceanside, CA 92054
Application Documents:
Original Application for Conditional Use Level Designation, Modular Wetland System,
Linear Stormwater Filtration System Modular Wetland Systems, Inc., January 2011
Quality Assurance Project Plan: Modular Wetland system Linear Treatment System
performance Monitoring Project, draft, January 2011.
Revised Application for Conditional Use Level Designation, Modular Wetland System,
Linear Stormwater Filtration System Modular Wetland Systems, Inc., May 2011
Memorandum:Modular Wetland System-Linear GULD Application Supplementary Data,
April 2014
Technical Evaluation Report: Modular Wetland System Stormwater Treatment System
Performance Monitoring, April 2014.
• Conduct inspections by qualified personnel, follow manufacturer's guidelines, and use
•
•
•
•
•
•
•
•
•
•
Applicant's Use Level Request:
General use level designation as a Basic, Enhanced, and Phosphorus treatment device in
Technologies Technology Assessment Protocol Ecology (TAPE) January 2011 Revision.
Applicant's Performance Claims:
The MWS Linear Modular wetland is capable of removing a minimum of 80-percent
of TSS from stormwater with influent concentrations between 100 and 200 mg/l.
The MWS Linear Modular wetland is capable of removing a minimum of 50-percent
of Total Phosphorus from stormwater with influent concentrations between 0.1 and 0.5
mg/l.
The MWS Linear Modular wetland is capable of removing a minimum of 30-percent
of dissolved Copper from stormwater with influent concentrations between 0.005 and
0.020 mg/l.
The MWS Linear Modular wetland is capable of removing a minimum of 60-percent
of dissolved Zinc from stormwater with influent concentrations between 0.02 and 0.30
mg/l.
Ecology Recommendations:
Modular Wetland Systems, Inc. has shown Ecology, through laboratory and field-
testing, that the MWS - Linear Modular Wetland Stormwater Treatment System filter
system is capable of attaining Ecology's Basic, Total phosphorus, and Enhanced
treatment goals.
Findings of Fact:
Laboratory Testing
The MWS-Linear Modular wetland has the:
Capability to remove 99 percent of total suspended solids (using Sil-Co-Sil 106) in a
quarter-scale model with influent concentrations of 270 mg/L.
Capability to remove 91 percent of total suspended solids (using Sil-Co-Sil 106) in
laboratory conditions with influent concentrations of 84.6 mg/L at a flow rate of 3.0
gpm per square foot of media.
Capability to remove 93 percent of dissolved Copper in a quarter-scale model with
influent concentrations of 0.757 mg/L.
Capability to remove 79 percent of dissolved Copper in laboratory conditions with
influent concentrations of 0.567 mg/L at a flow rate of 3.0 gpm per square foot of
media.
Capability to remove 80.5-percent of dissolved Zinc in a quarter-scale model with
influent concentrations of 0.95 mg/L at a flow rate of 3.0 gpm per square foot of media.
Capability to remove 78-percent of dissolved Zinc in laboratory conditions with influent
concentrations of 0.75 mg/L at a flow rate of 3.0 gpm per square foot of media.
accordance with Ecology's Guidance for Evaluating Emerging Stormwater Treatment
•
•
•
•
•
•
•
•
•
•
•
Field Testing
Modular Wetland Systems, Inc. conducted monitoring of an MWS-Linear (Model
# MWS-L-4-13) from April 2012 through May 2013, at a transportation maintenance
facility in Portland, Oregon. The manufacturer collected flow-weighted composite
effluent during 28 separate storm events. The
system treated approximately 75 percent of the runoff from 53.5 inches of rainfall
during the monitoring period. The applicant sized the system at 1 gpm/sq ft. (wetland
media) and 3gpm/sq ft. (prefilter).
Influent TSS concentrations for qualifying sampled storm events ranged from 20 to 339
mg/L. Average TSS removal for influent concentrations greater than 100 mg/L (n=7)
averaged 85 percent. For influent concentrations in the range of 20-100 mg/L (n=18),
the upper 95 percent confidence interval about the mean effluent concentration was
12.8 mg/L.
Total phosphorus removal for 17 events with influent TP concentrations in the range of
0.1 to 0.5 mg/L averaged 65 percent. A bootstrap estimate of the lower 95 percent
confidence limit (LCL95) of the mean total phosphorus reduction was 58 percent.
The lower 95 percent confidence limit of the mean percent removal was 60.5 percent for
dissolved zinc for influent concentrations in the range of 0.02 to 0.3 mg/L (n=11).
The lower 95 percent confidence limit of the mean percent removal was 32.5 percent for
dissolved copper for influent concentrations in the range of 0.005 to 0.02 mg/L (n=14)
at flow rates up to 28 gpm (design flow rate 41 gpm). Laboratory test data augmented
the data set, showing dissolved copper removal at the design flow rate of 41 gpm (93
percent reduction in influent dissolved copper of 0.757 mg/L).
Issues to be addressed by the Company:
1. Modular Wetland Systems, Inc. should collect maintenance and inspection data for the
first year on all installations in the Northwest in order to assess standard maintenance
requirements for various land uses in the region. Modular Wetland Systems, Inc. should
use these data to establish required maintenance cycles.
2. Modular Wetland Systems, Inc. should collect pre-treatment chamber sediment depth
data for the first year of operation for all installations in the Northwest. Modular
Wetland Systems, Inc. will use these data to create a correlation between sediment depth
and pre-filter clogging.
Technology Description:
Download at http://www.modularwetlands.com/
Contact Information:
Applicant:Zach Kent
BioClean A Forterra Company.
398 Vi9a El Centro
Oceanside, CA 92058
zach.kent@forterrabp.com
•
samples of the system's influent and
•
•
•
Applicant website:http://www.modularwetlands.com/
Ecology web link:http://www.ecy.wa.gov/programs/wg/stormwater/newtech/index.html
Ecology: Douglas C. Howie, P.E.
Department of Ecology
Water Quality Program
(360) 407-6444
douglas.howie@ecy.wa.gov
Revision History
Date Revision
June 2011 Original use-level-designation document
September 2012 Revised dates for TER and expiration
January 2013 Modified Design Storm Description, added Revision Table, added
maintenance discussion, modified format in accordance with Ecology
standard
December 2013 Updated name of Applicant
April 2014 Approved GULD designation for Basic, Phosphorus, and Enhanced
treatment
December 2015 Updated GULD to document the acceptance of MWS-Linear
Modular Wetland installations with or without the inclusion of plants
July 2017 Revised Manufacturer Contact Information (name, address, and
email)
Bio ~Clean
A Forterra Company
OVERVIEW
The Bio Clean Modular Wetlands® System Linear represents a pioneering breakthrough in stormwater
technology as the only biofiltration system to utilize patented horizontal flow, allowing for a smaller
footprint, higher treatment capacity, and a wide range of versatility. While most biofilters use little
or no pretreatment, the Modular Wetlands® incorporates an advanced pretreatment chamber that
includes separation and pre-filter cartridges. In this chamber, sediment and hydrocarbons are removed
from runoff before entering the biofiltration chamber, reducing maintenance costs and improving
performance.
Horizontal flow also gives the system the unique ability to adapt to the environment
through a variety of configurations, bypass orientations, and diversion applications.
The Urban Impact
For hundreds of years, natural wetlands surrounding our shores have
played an integral role as nature's stormwater treatment system.
But as cities grow and develop, our environment's natural
filtration systems are blanketed with impervious roads,
rooftops, and parking lots.
Bio Clean understands this loss and has spent
years re-establishing nature's presence in urban
areas, and rejuvenating waterways with the
Modular Wetlands® System Linear.
APPROVALS
The Modular Wetlands® System Linear has successfully met years of challenging technical reviews and
testing from some of the most prestigious and demanding agencies in the nation and perhaps the world.
Here is a list of some of the most high-profile approvals, certifications, and verifications from around the
country.
ii • • .
Washington State Department of Ecology TAPE Approved
The MWS Linear is approved for General Use Level Designation (GULD) for Basic,
Enhanced, and Phosphorus treatment at 1 gpm/ft2 loading rate. The highest performing
BMP on the market for all main pollutant categories.
California Water Resources Control Board, Full Capture Certification
The Modular Wetlands® System is the first biofiltration system to receive certification as
a full capture trash treatment control device.
Virginia Department of Environmental Quality, Assignment
The Virginia Department of Environmental Quality assigned the MWS Linear the
highest phosphorus removal rating for manufactured treatment devices to meet the new
Virginia Stormwater Management Program (VSMP) regulation technical criteria.
Maryland Department of the Environment, Approved ESD
Granted Environmental Site Design (ESD) status for new construction, redevelopment,
and retrofitting when designed in accordance with the design manual.
MASTEP Evaluation
The University of Massachusetts at Amherst -Water Resources Research Center issued
a technical evaluation report noting removal rates up to 84% TSS, 70% total phosphorus,
68.5% total zinc, and more.
Rhode Island Department of Environmental Management, Approved BMP
Approved as an authorized BMP and noted to achieve the following minimum removal
efficiencies: 85% TSS, 60% pathogens, 30% total phosphorus, and 30% total nitrogen.
OPERATION
The Modular Wetlands® System Linear is the most efficient and versatile biofiltration system on the
market, and it is the only system with horizontal flow which:
Improves performance
Reduces footprint
• Minimizes maintenance
Figure 1 & Figure 2 illustrate the invaluable benefits of horizontal flow and the multiple treatment stages.
0 PRETREATMENT
SEPARATION
• Trash, sediment, and debris are separated before
entering the pre-filter cartridges
• Designed for easy maintenance access
PRE-FILTER CARTRIDGES
• Over 25 sq. ft. of surface area per cartridge
• Utilizes BioMediaGREEN™ filter material
• Removes over 80% of TSS and 90% of hydrocarbons
• Prevents pollutants that cause clogging from migrating
to the biofiltration chamber
Individual Media Filters
Cartridge Housing
Curb Inlet
Pre-filter Cartridge
BioMediaGREEN™
Vertical Underdrain
Manifold
WetlandMEDIA'"
PERIMETER V
01D AREA
Riser
Draindown Line
® BIOFILTRATION
HORIZONTAL FLOW
• Less clogging than downward flow biofilters
• Water flow is subsurface
• Improves biological filtration
PATENTED PERIMETER VOID AREA
• Vertically extends void area between the walls and
the WetlandMEDIA'" on all four sides
• Maximizes surface area of the media for higher
treatment capacity
WETLANDMEDIA
• Contains no organics and removes phosphorus
• Greater surface area and 48% void space
• Maximum evapotranspiration
• High ion exchange capacity and lightweight
Figurel 0 DISCHARGE
Outlet Pipe
FLOW CONTROL
• Orifice plate controls flow of water
through WetlandMEDIA'" to a level lower
than the media's capacity
• Extends the life of the media and
improves performance
DRAINDOWN FILTER
• The draindown is an optional feature that
completely drains the pretreatment
chamber
• Water that drains from the pretreatment
chamber between storm events will be
treated
CONFIGURATIONS
The Modular Wetlands® System Linear is the preferred biofiltration system of civil engineers across the
country due to its versatile design. This highly versatile system has available "pipe-in" options on most
models, along with built-in curb or grated inlets for simple integration into your storm drain design.
CURB TYPE
The Curb Type configuration accepts sheet flow through a curb opening
and is commonly used along roadways and parking lots. It can be used in
sump or flow-by conditions. Length of curb opening varies based on model
and size.
GRATE TYPE
The Grate Type configuration offers the same features and benefits as the
Curb Type but with a grated/drop inlet above the systems pretreatment
chamber. It has the added benefit of allowing pedestrian access over the
inlet. ADA-compliant grates are available to assure easy and safe access.
The Grate Type can also be used in scenarios where runoff needs to be
intercepted on both sides of landscape islands.
VAULT TYPE
The system's patented horizontal flow biofilter is able to accept inflow pipes
directly into the pretreatment chamber, meaning the Modular Wetlands®
can be used in end-of-the-line installations. This greatly improves feasibility
over typical decentralized designs that are required with other biofiltration/
bioretention systems. Another benefit of the "pipe-in" design is the ability
to install the system downstream of underground detention systems to
meet water quality volume requirements.
DOWNSPOUT TYPE
The Downspout Type is a variation of the Vault Type and is designed to
accept a vertical downspout pipe from rooftop and podium areas. Some
models have the option of utilizing an internal bypass, simplifying the overall
design. The system can be installed as a raised planter, and the exterior can
be stuccoed or covered with other finishes to match the look of adjacent
buildings.
ORIENTATIONS
SIDE-BY-SIDE
The Side-By-Side
orientation places the
pretreatment and
discharge chamber
adjacent to one
another with the
biofiltration chamber running
parallel on either side. This
minimizes the system length, providing a highly
compact footprint. It has been proven useful in
situations such as streets with directly adjacent
sidewalks, as half of the system can be placed
under that sidewalk. This orientation also offers
internal bypass options as discussed below.
BYPASS
INTERNAL BYPASS WEIR
(SIDE-BY-SIDE ONLY)
The Side-By-Side orientation places the
pretreatment and discharge chambers adjacent
to one another allowing for integration of internal
bypass. The wall between these chambers can act
as a bypass weir when flows exceed the system's
treatment capacity, thus allowing bypass from the
pretreatment chamber directly to the discharge
chamber.
EXTERNAL DIVERSION WEIR STRUCTURE
This traditional offline diversion method can be
used with the Modular Wetlands® in scenarios
where runoff is being piped to the system. These
simple and effective structures are generally
configured with two outflow pipes. The first is a
smaller pipe on the upstream side of the diversion
weir -to divert low flows over to the Modular
Wetlands® for treatment. The second is the main
pipe that receives water once the system has
exceeded treatment capacity and water flows over
the weir.
FLOW-BY-DESIGN
This method is one in which the system is placed
just upstream of a standard curb or grate inlet to
intercept the first flush. Higher flows simply pass
by the Modular Wetlands® and into the standard
inlet downstream.
END-TO-END
The End-To-End orientation
places the pretreatment and
discharge chambers
on opposite ends of the
biofiltration chamber,
therefore minimizing the width
of the system to 5 ft. (outside
dimension). This orientation is perfect
for linear projects and street retrofits
where existing utilities and sidewalks limit the
amount of space available for installation. One
limitation of this orientation is that bypass must
be external.
OVERT LOW FLOW DIVERSION
This simple yet innovative diversion trough can be
installed in existing or new curb and grate inlets
to divert the first flush to the Modular Wetlands®
via pipe. It works similar to a rain gutter and is
installed just below the opening into the inlet. It
captures the low flows and channels them over
to a connecting pipe exiting out the wall of the
inlet and leading to the MWS Linear. The DVERT
is perfect for retrofit and green street applications
that allow the Modular Wetlands® to be installed
anywhere space is available.
SPECIFICATIONS
FLOW-BASED DESIGNS
The Modular Wetlands® System Linear can be used in stand-alone applications to meet treatment flow
requirements. Since the Modular Wetlands® is the only biofiltration system that can accept inflow pipes
several feet below the surface, it can be used not only in decentralized design applications but also as a large
central end-of-the-line application for maximum feasibility.
MWS-L-4-6 4' X 6' 32 0.073
MWS-L-4-8 4' X 8' 50 0.115
MWS-L-4-13 4' X 13' 63 0.144
MWS-L-4-15 4' X 15' 76 0.175
MWS-L-4-17 4' X 17' 90 0.206
MWS-L-4-19 4' X 19' 103 0.237
MWS-L-4-21 4' X 21' 117 0.268
MWS-L-6-8 7'x9' 64 0.147
MWS-L-8-8 8' X 8' 100 0.230
MWS-L-8-12 8' x12' 151 0.346
MWS-L-8-16 8' X 16' 201 0.462
MWS-L-8-20 9' X 21' 252 0577
MWS-L-8-24 9' X 25' 302 0.693
MWS-L-10-20 10' X 20' 302 0.693
VOLUME-BASED DESIGNS
HORIZONTAL FLOW BIOFILTRATION ADVANTAGE
Box Culvert Prestorage
The Modular Wetlands® System Linear offers a unique advantage in the world of biofiltration due to its exclusive
horizontal flow design: Volume-Based Design. No other biofilter has the ability to be placed downstream
of detention ponds, extended dry detention basins, underground storage systems and permeable paver
reservoirs. The systems horizontal flow configuration and built-in orifice control allows it to be installed with
just 6" of fall between inlet and outlet pipe for a simple connection to projects with shallow downstream tie-
in points. In the example above, the Modular Wetlands® is installed downstream of underground box culvert
storage. Designed for the water quality volume, the Modular Wetlands® will treat and discharge the required
volume within local draindown time requirements.
Modular Wetlands" with
DESIGN SUPPORT
Bio Clean engineers are trained to provide you with superior support for all volume sizing configurations
throughout the country. Our vast knowledge of state and local regulations allow us to quickly and efficiently
size a system to maximize feasibility. Volume control and hydromodification regulations are expanding the
need to decrease the cost and size of your biofiltration system. Bio Clean will help you realize these cost
savings with the Modular Wetlands®, the only biofilter than can be used downstream of storage BMPs.
ADVANTAGES
LOWER COST THAN FLOW-BASED DESIGN
MEETS LID REQUIREMENTS
BUILT-IN ORIFICE CONTROL STRUCTURE
WORKS WITH DEEP INSTALLATIONS
ATTACHMENT 4
SINGLE SHEET BMP EXHIBIT
ATTACHMENT 4
City standard Single Sheet BMP (SSBMP) Exhibit
[Use the City’s standard Single Sheet BMP Plan.]
HI G HL AN D DR I VE
ADAMS STREET
206-192-07
206-180-38
APN 206-192-08
4464 ADAMS STREET
PAD=92.0
9
6 7
8
5
4
3 2 1
10
11
11
12
12
12
12
12
12
12
FUSION ENG TECH
1810 GILLESPIE WAY # 207
EL CAJON, CA 92020
(619) 736-2800
ROOF DRAIN TO
LANDSCAPING1
BMP TYPEBMP ID #SYMBOL CASQA NO.DRAWING NO.SHEET NO.(S)MAINTENANCE
FREQUENCY
BMP TABLE
1. THESE BMPS ARE MANDATORY TO BE INSTALLED PER MANUFACTURER'S
RECOMMENDATIONS OR THESE PLANS.
2. NO CHANGES TO THE PROPOSED BMPS ON THIS SHEET WITHOUT PRIOR
APPROVAL FROM THE CITY ENGINEER.
3. NO SUBSTITUTIONS TO THE MATERIAL OR TYPES OR PLANTING TYPES
WITHOUT PRIOR APPROVAL FROM THE CITY ENGINEER.
4. NO OCCUPANCY WILL BE GRANTED UNTIL THE CITY INSPECTION STAFF
HAS INSPECTED THIS PROJECT FOR APPROPRIATE BMP CONSTRUCTION
AND INSTALLATION.
BMP NOTES:
PARTY RESPONSIBLE FOR MAINTENANCE:
NAME
ADDRESS
PHONE NO.
PLAN PREPARED BY:
NAME
ADDRESS
PHONE NO.
CERTIFICATION
COMPANY
SD-B
INSPECTION
FREQUENCYQUANTITY
TREATMENT CONTROL
LOW IMPACT DESIGN (L.I.D.) SITE AND SOURCE CONTROLS
9
5. REFER TO MAINTENANCE AGREEMENT DOCUMENT.
8 EA.533-8L 5 ANNUALLY ANNUALLY
BF-3-1 COMPACT SEMI-ANNUALLY1 EA.533-8A 5
**
6. SEE PROJECT SWMP FOR ADDITIONAL INFORMATION.
SIGNATURE
ANNUALLY
BMP CONSTRUCTION AND INSPECTION NOTES:
THE EOW WILL VERIFY THAT PERMANENT BMPS ARE
CONSTRUCTED AND OPERATING IN COMPLIANCE WITH THE
APPLICABLE REQUIREMENTS. PRIOR TO OCCUPANCY THE
EOW MUST PROVIDE:
1. PHOTOGRAPHS OF THE INSTALLATION OF PERMANENT
BMPS PRIOR TO CONSTRUCTION, DURING
CONSTRUCTION, AND AT FINAL INSTALLATION.
2. A WET STAMPED LETTER VERIFYING THAT PERMANENT
BMPS ARE CONSTRUCTED AND OPERATING PER THE
REQUIREMENTS OF THE APPROVED PLANS.
3. PHOTOGRAPHS TO VERIFY THAT PERMANENT WATER
QUALITY TREATMENT SIGNAGE HAS BEEN INSTALLED.
PRIOR TO RELEASE OF SECURITIES, THE DEVELOPER IS
RESPONSIBLE FOR ENSURING THE PERMANENT BMPS HAVE
NOT BEEN REMOVED OR MODIFIED BY THE NEW HOMEOWNER
OR HOA WITHOUT THE APPROVAL OF THE CITY ENGINEER.
JOHN FORESTER
4464 ADAMS STREET
CARLSBAD, CA 92008
760-535-4343
JOHN S. RIVERA
FUSION ENG. & TECH.
4231 BALBOA AVE. #619
SAN DIEGO, CA 92117
619-992-6618
PROPRIETARY
BIOFILTRATION MWS
SEMI-ANNUALLY1 EA.533-8L 5 ANNUALLYTREE WELL*10 SD-A
* SEE SHEET 2 FOR DETAILS.
SEMI-ANNUALLYPER PLAN 533-8L 5 ANNUALLY11SD-G
SEMI-ANNUALLY10,988 S.F.533-8L 5 ANNUALLY12SD-K
CONSERVE NAT.
FEATURES
SUSTAINABLE
LANDSCAPING
\
\
\
. ·"""" ---------o0o---u 0 ---.. OUNDARY-UN&--
1-----w----.___
20
D
0-0 •
0 ®
0
0 1. · . · .1
0 20 40 60 -----
SCALE 1 "= 20'
"AS BU IL T"
RCE __ _ EXP ____ _ DATE
REVIEWED BY:
INSPECTOR DATE
1-----+--+------------+---+----+---+--------l I SH8EET I CITY OF CARLSBAD ~4 ENGINEERING DEPARTMENT Ll±_J
~G::;R=A:;:DI:;N::::'G,..':::&=:;IM:::;P;::R;::O::;:VE:;:::M:;EN;::T:;:::;P;::L=AN:::;:::S =F;:O;::R=: ===--======
1
DA TE INITIAL DATE INITIAL DATE INITIAL
ENGINEER OF WORK REVISION DESCRIPTION OTHER APPROVAL CITY APPROVAL
FORESTER RESIDENCE
4464 ADAMS STREET
GR2021-0037 SINGLE SHEET BMP SITE PLAN
APPROVED: JASON S. GELDERT
ENGINEERING MANAGER RCE 63912 EXPIRES 9 30 22 DATE
OWN BY:
CHKD BY: __ _
RVWD BY:
PROJECT NO.
CDP 2020-0018
DRAWING NO.
533-8A
ATTACHMENT 5
GEOTECHNICAL REPORT
ADVANCED GEOTECHNICAL SOLUTIONS, INC.
485 Corporate Drive, Suite B
Escondido, California 92029
Telephone: (619) 867-0487 Fax: (714) 409-3287
ORANGE AND L.A. COUNTIES INLAND EMPIRE SAN DIEGO AND IMPERIAL COUNTIES
(714) 786-5661 (619) 867-0487 (619) 867-0487
John Forester December 31, 2019
300 Carlsbad Village Drive, Suite 108a-335 P/W 1901-03
Carlsbad, California 92008 Report No. 1901-03-B-2
Attention: Mr. John Forester
Subject: Geotechnical Investigation and Preliminary Design Recommendations for Proposed
Single-Family Residence, 4464 Adams Street, Carlsbad, California
References: See Appendix A
Gentlemen:
Presented herein are the results of Advanced Geotechnical Solutions, Inc.’s, (AGS’s) geotechnical
investigation and preliminary design recommendations for the proposed single-family residence at 4464
Adams Street in the City of Carlsbad, California. The purpose of this geotechnical investigation is to
evaluate the proposed development relative to the near-site and on-site geologic and geotechnical
conditions, as well as to provide conclusions and recommendation to aid in the construction of the proposed
residential structure and improvements.
Advanced Geotechnical Solutions, Inc., appreciates the opportunity to provide you with geotechnical
consulting services and professional opinions. If you have any questions, please contact the undersigned
at (619) 867-0487.
Respectfully Submitted,
Advanced Geotechnical Solutions, Inc.
__________________________________
SHANE P. SMITH
Staff Engineer
___________________________________ _______________________________
ANDRES BERNAL, Sr. Geotechnical Engineer PAUL J. DERISI
RCE 62366/GE 2715, Reg. Exp. 9-30-21 CEG 2536, Reg. Exp. 5-31-21
Distribution: (1) Addressee (pdf)
December 31, 2019 Page ii
P/W 1909-11 Report No. 1909-11-B-2
ADVANCED GEOTECHNICAL SOLUTIONS, INC.
TABLE OF CONTENTS
Page
1.0 INTRODUCTION .............................................................................................................. 1
1.1. Scope of Work ................................................................................................................ 1
1.2. Geotechnical Study Limitations ...................................................................................... 1
2.0 SITE AND PROJECT DESCRIPTION.............................................................................. 2
3.0 FIELD AND LABORATORY INVESTIGATION ........................................................... 2
4.0 ENGINEERING GEOLOGY ............................................................................................. 2
4.1. Geologic Analysis ........................................................................................................... 2
4.1.1. Literature Review.................................................................................................... 2
4.1.2. Aerial Photograph and Historic U.S.G.S. Map Review .......................................... 2
4.1.3. Field Mapping......................................................................................................... 2
4.2. Geologic and Geomorphic Setting .................................................................................. 2
4.3. Stratigraphy ..................................................................................................................... 3
4.3.1. Artificial Fill – Undocumented (Map symbol afu) ................................................. 3
4.3.2. Old Paralic Deposits (Map symbol Qop2-4) ............................................................ 3
4.4. Groundwater ................................................................................................................... 3
4.5. Non-seismic Geologic Hazards....................................................................................... 3
4.5.1. Mass Wasting and Debris Flows............................................................................. 3
4.5.2. Subsidence and Ground Fissuring .......................................................................... 4
4.5.3. Flooding .................................................................................................................. 4
4.6. Seismic Hazards .............................................................................................................. 4
4.6.1. Surface Fault Rupture ............................................................................................. 4
4.6.2. Seismic Design Parameters ..................................................................................... 4
4.6.3. Seismicity ................................................................................................................ 5
4.6.4. Liquefaction ............................................................................................................ 5
4.6.5. Dynamic Settlement ................................................................................................ 5
4.6.6. Seismically Induced Landsliding............................................................................ 5
4.6.7. Tsunamis ................................................................................................................. 6
5.0 GEOTECHNICAL ENGINEERING .................................................................................. 6
5.1. Material Properties .......................................................................................................... 6
5.1.1. Excavation Characteristics ...................................................................................... 6
5.1.2. Compressibility ....................................................................................................... 6
5.1.3. Collapse Potential/Hydro-Consolidation ................................................................ 6
5.1.4. Expansion Potential ................................................................................................ 6
5.1.5. Chemical and Resistivity Test Results .................................................................... 7
5.1.6. Pavement Support Characteristics .......................................................................... 7
5.1.7. Shear Strength ......................................................................................................... 7
5.1.8. Earthwork Adjustments .......................................................................................... 7
5.2. Analytical Methods......................................................................................................... 7
5.2.1. Bearing Capacity ..................................................................................................... 7
5.2.2. Lateral Earth Pressures ........................................................................................... 8
6.0 GRADING AND SHORING RECOMMENDATIONS .................................................... 8
6.1. Earthwork Recommendations......................................................................................... 8
6.1.1. Site Preparation....................................................................................................... 8
6.1.2. Removals................................................................................................................. 8
December 31, 2019 Page iii
P/W 1909-11 Report No. 1909-11-B-2
ADVANCED GEOTECHNICAL SOLUTIONS, INC.
6.2. Earthwork Considerations ............................................................................................... 8
6.2.1. Compaction Standards ............................................................................................ 8
6.2.2. Benching ................................................................................................................. 9
6.2.3. Mixing and Moisture Control ................................................................................. 9
6.2.4. Import Soils ............................................................................................................. 9
6.3. Temporary Excavations .................................................................................................. 9
6.4. Utility Trench Backfill.................................................................................................. 10
6.5. Flatwork Subgrade Preparation ..................................................................................... 10
7.0 CONCLUSIONS AND DESIGN RECOMMENDATIONS............................................ 10
7.1. Structural Design .......................................................................................................... 10
7.1.1. Foundation Design ................................................................................................ 10
7.1.2. Moisture and Vapor Barrier .................................................................................. 12
7.2. Conventional Retaining Walls ...................................................................................... 12
7.3. Concrete Design ............................................................................................................ 13
7.4. Corrosion....................................................................................................................... 14
7.5. Site Drainage ................................................................................................................. 14
7.6. Exterior Flatwork .......................................................................................................... 14
8.0 FUTURE STUDY NEEDS ............................................................................................... 14
8.1. Construction Plans ........................................................................................................ 14
8.2. Observation During Construction ................................................................................. 15
9.0 CLOSURE ........................................................................................................................ 15
ATTACHMENTS:
Figure 1 - Site Location Map
Figure 2 - Regional Geologic Map
Plate 1 - Geologic and Exploration Location Plan
Appendix A - References
Appendix B - Log of Exploratory Borings
Appendix C - Laboratory Test Results
December 31, 2019 Page 1
P/W 1901-03 Report No. 1901-03-B-2
ADVANCED GEOTECHNICAL SOLUTIONS, INC.
GEOTECHNICAL INVESTIGATION AND
PRELIMINARY DESIGN RECOMMENDATIONS FOR
PROPOSED SINGLE-FAMILY RESIDENCE
4464 ADAMS STREET, CARLSBAD, CALIFORNIA
1.0 INTRODUCTION
Advanced Geotechnical Solutions, Inc., (AGS) has prepared this report which presents the results of our
geotechnical investigation onsite and provides specific recommendations for the design and construction
of the proposed single-family residence at 4464 Adams Street in Carlsbad, California.
1.1. Scope of Work
The scope of our study included the following tasks:
➢ Review of pertinent published and unpublished geologic and geotechnical literature, maps,
and aerial photographs readily available to this firm.
➢ Advance, log, and sample three (3) solid flight auger borings to depths of 21.5 feet below
ground surface on December 31, 2019 (B-1 through B-3). The boring logs are presented in
Appendix B.
➢ Conduct laboratory testing on the collected soil samples to evaluate the engineering
properties of the subsurface materials. Laboratory results are presented in Appendix C.
➢ Conduct a geotechnical engineering and geologic hazard analysis of the site.
➢ Evaluate groundwater conditions and the potential effects on construction.
➢ Conduct a limited seismic hazards evaluation including research of readily available
published maps and reports.
➢ Determine preliminary design parameters for foundations.
➢ Provide a preliminary corrosivity evaluation of the onsite soils.
➢ Prepare this report with exhibits summarizing our findings. This report would be suitable
for design, construction, and regulatory review.
1.2. Geotechnical Study Limitations
The conclusions and recommendations in this report are professional opinions based on the data
developed during this investigation. The conclusions presented herein are based upon the current
design concept. Changes to the design concept would necessitate further review.
The materials immediately adjacent to or beneath those observed may have different characteristics
than those observed. No representations are made as to the quality or extent of materials not
observed. Any evaluation regarding the presence or absence of hazardous material is beyond the
scope of this firm’s services.
December 31, 2019 Page 2
P/W 1901-03 Report No. 1901-03-B-2
ADVANCED GEOTECHNICAL SOLUTIONS, INC.
2.0 SITE AND PROJECT DESCRIPTION
The roughly triangular shaped site encompasses approximately one-half acre and is generally located east
of the intersection of Adams Street and Highland Drive in Carlsbad, California (Figure 1). The site is
bounded by Highland Drive on the northwest, Adams Street on the southwest, and vacant undeveloped land
on the east. Topography at the site is generally sloping down to the south and west. Elevations across the
site range from approximately 105 feet above msl in the northeast corner of the site to 70 feet above msl in
the southeast corner of the site. The site is graded and currently supports a single-family residence and
associated improvements. The existing improvements will be razed to allow for new construction.
It is our understanding that the project will consist of a one- to two-story single-family residence with a
partially subterranean basement level. It is anticipated that the structure will be supported by conventional
spread and continuous footings and will consist of CMU or poured in place concrete construction for the
underground level with wood framing on the above ground levels. Access will be afforded from Highland
Drive along the northwesterly property boundary.
3.0 FIELD AND LABORATORY INVESTIGATION
AGS conducted a geotechnical investigation of the subject property in December 2019. As part of the
investigation three (3) solid flight auger soil borings were excavated onsite, logged, and sampled by a
representative of this firm. The borings were excavated to a maximum depth of 21.5 feet below ground
surface. Boring logs are presented in Appendix B with boring locations presented on Plate 1.
Representative bulk and “undisturbed” ring samples were transported to our laboratory for testing. Testing
included in-situ moisture content and density, shear strength, maximum density and optimum moisture
content, expansion potential and chemical/corrosivity analysis. Laboratory test results are presented in
Appendix C.
4.0 ENGINEERING GEOLOGY
4.1. Geologic Analysis
4.1.1. Literature Review
AGS has reviewed the referenced geologic documents (see Appendix A) in preparing this
study. Where deemed appropriate, this information has been included with this document.
4.1.2. Aerial Photograph and Historic U.S.G.S. Map Review
AGS has reviewed the aerial photographs available online and in our library as well as
historic U.S.G.S. quadrangle maps.
4.1.3. Field Mapping
A site reconnaissance was conducted at the site and its immediate vicinity.
4.2. Geologic and Geomorphic Setting
The subject site is situated within the Peninsular Ranges Geomorphic Province. The Peninsular
Ranges province occupies the southwestern portion of California and extends southward to the
southern tip of Baja California. In general the province consists of young, steeply sloped, northwest
FIGURE
1
DATE:
1/20
SITE LOCATION MAP
PROJECT NO.:
1901-03
N
NOTE: ALL DIMENSIONS, DIRECTIONS AND LOCATIONS ARE APPROXIMATE.SOURCE: USGS, THE NATIONAL MAP, 2020.
SITE
SINGLE FAMILY RESIDENCE
4464 ADAMS STREET
CARLSBAD, CALIFORNIA
See e· '·18 05
Zoo e e 5
0.3m,
Agua f-ied1011da
GS
December 31, 2019 Page 3
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trending mountain ranges underlain by metamorphosed Late Jurassic to Early Cretaceous-aged
extrusive volcanic rock and Cretaceous-aged igneous plutonic rock of the Peninsular Ranges
Batholith. The westernmost portion of the province, where the subject site is located, is
predominantly underlain by younger marine and non-marine sedimentary rocks. The Peninsular
Ranges’ dominant structural feature is northwest-southeast trending crustal blocks bounded by
active faults of the San Andreas transform system.
4.3. Stratigraphy
The project site is mapped as being underlain by old paralic deposits (terrace deposits) overlying
Tertiary age Santiago Formation as shown in Figure 2, Regional Geologic Map. AGS encountered
materials considered to be associated with the old paralic deposits during our investigation at the
site. A description of the geologic units encountered is provided below. More detailed descriptions
of these materials are provided in the boring logs included in Appendix B.
4.3.1. Artificial Fill – Undocumented (Map symbol afu)
Undocumented artificial fill was encountered within borings B-1 through B-3 with an
approximate thickness of 2.5 to 5 feet. The fill material was observed to be silty fine- to
medium-grained sand with trace clay and occasional roots and debris that is dark gray
brown to dark yellow brown in a moist to very moist and loose condition. Additional
undocumented artificial fill deposits may be encountered throughout the site.
4.3.2. Old Paralic Deposits (Map symbol Qop2-4)
Pleistocene age old paralic deposits were encountered within all three borings excavated
onsite (B-1 through B-3) to the maximum depth explored. This unit was generally observed
to consist of yellow brown to gray brown to red brown, silty sand with clay in a slightly
moist to moist and medium dense to dense condition. Interbedded silt lenses were
encountered in boring B-1 below a depth of 15 feet.
4.4. Groundwater
Groundwater was not encountered in the recent exploratory excavations by AGS. No natural
groundwater condition is known to exist at the site that would impact the proposed site
development. However, it should be noted that localized perched groundwater may develop at a
later date, most likely at or near fill/bedrock contacts, due to fluctuations in precipitation, irrigation
practices, or factors not evident at the time of our field explorations. In general, all subterranean
portions of the proposed structures will require waterproofing and drainage.
4.5. Non-seismic Geologic Hazards
4.5.1. Mass Wasting and Debris Flows
No evidence of mass wasting or debris flows was observed onsite nor was any noted on
the reviewed maps.
FIGURE
2
DATE
1/20
PROJECT NO.
1901-03
REGIONAL GEOLOGIC MAP
NOTE: ALL DIMENSIONS, DIRECTIONS AND LOCATIONS ARE APPROXIMATE.
SINGLE FAMILY RESIDENCE
4464 ADAMS STREET
CARLSBAD, CALIFORNIA
LEGEND
N
SOURCE: GEOLOGIC MAP OF THE OCEANSIDE 30 X 60 QUADRANGLE, 2007.
SITE
Alluvial flood-plain deposits (late Holocene)
Old alluvial Hood-plain deposits, undivided (late to middle
Pleistocene)
Old paralic deposits, undivided (late to middle Pleistocene)
I Qop2-4 I Units 2-4
~ Santiago Formation (middle Eocene)
GS
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4.5.2. Subsidence and Ground Fissuring
Evidence of ground fissuring has not been identified on the site, and AGS is unaware of
ground fissuring the surrounding areas.
4.5.3. Flooding
According to available FEMA maps, the site is not in a FEMA identified flood hazard area.
4.6. Seismic Hazards
The site is located in the tectonically active Southern California area, and will therefore likely
experience shaking effects from earthquakes. The type and severity of seismic hazards affecting
the site are to a large degree dependent upon the distance to the causative fault, the intensity of the
seismic event, the direction of propagation of the seismic wave and the underlying soil
characteristics. The seismic hazard may be primary, such as surface rupture and/or ground shaking,
or secondary, such as liquefaction, seismically induced slope failure or dynamic settlement. The
following is a site-specific discussion of ground motion parameters, earthquake-induced landslide
hazards, settlement, and liquefaction. The purpose of this analysis is to identify potential seismic
hazards and propose mitigations, if necessary, to reduce the hazard to an acceptable level of risk.
The following seismic hazards discussion is guided by the California Building Code (2016),
CDMG (2008), and Martin and Lew (1998).
4.6.1. Surface Fault Rupture
There are no known active surface faults that transect or project into the subject site. The
nearest known active surface fault is the Rose Canyon fault zone which is approximately
2.1 miles west of the site. Accordingly, the potential for fault surface rupture on the subject
site is low. This conclusion is based on literature review and aerial photographic analysis.
4.6.2. Seismic Design Parameters
Based on our subsurface exploration, the site may be classified as Seismic Site Class D
consisting of a “stiff soil” profile with average NSPT blow count ranging between 15 to 50
blows/foot. Site coordinates of Latitude 32.7519° N and Longitude -117.2309° W were
utilized in conjunction with the SEAOC/OSHPD Seismic Design Maps web-based ground
motion calculator (https://seismicmaps.org/) to obtain the 2016 CBC seismic design
parameters presented in Table 4.6.3.
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TABLE 4.6.3.
2016 CALIFORNIA BUILDING CODE DESIGN PARAMETERS
Seismic Site Class D
Mapped Spectral Acceleration Parameter at Period of 0.2-Second, Ss 1.195g
Mapped Spectral Acceleration Parameter at Period 1-Second, S1 0.457g
Site Coefficient, Fa 1.022
Site Coefficient, Fv 1.543
Adjusted MCER1 Spectral Response Acceleration Parameter at Short Period, SMS 1.221g
1-Second Period Adjusted MCER1 Spectral Response Acceleration Parameter, SM1 0.705g
Short Period Design Spectral Response Acceleration Parameter, SDS 0.814g
1-Second Period Design Spectral Response Acceleration Parameter, SD1 0.470g
Peak Ground Acceleration, PGAM2 0.524g
Seismic Design Category D
Note: 1 Targeted Maximum Considered Earthquake
2 Peak Ground Acceleration adjusted for site effects
4.6.3. Seismicity
As noted, the site is within the tectonically active southern California area, and is
approximately 2.1 miles from an active fault, the Oceanside section of the Newport-
Inglewood-Rose Canyon fault zone. The potential exists for strong ground motion that
may affect future improvements.
At this point in time, non-critical structures (commercial, residential, and industrial) are
usually designed according to the California Building Code (2016) and that of the
controlling local agency. However, liquefaction/seismic slope stability analyses, critical
structures, water tanks and unusual structural designs will likely require site specific
ground motion input.
4.6.4. Liquefaction
Due to the lack of loose saturated granular materials, and dense nature and age of the
underlying old paralic deposits, the potential for seismically induced liquefaction is
considered remote.
4.6.5. Dynamic Settlement
Dynamic settlement occurs in response to an earthquake event in loose sandy earth
materials. This potential of dynamic settlement at the subject site is considered very low
within the underlying formational materials.
4.6.6. Seismically Induced Landsliding
Evidence of landsliding at the site was not observed during our field explorations nor was
any geomorphic features indicative of landsliding noted during our review of aerial photos
and published geologic maps.
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4.6.7. Tsunamis
Our review of the 2009 Tsunami Inundation Map for Emergency Planning, Oceanside and
San Luis Rey Quadrangles, prepared by CalEMA, indicates the project site is not within a
potential inundation area. It is our opinion that tsunamis are not a significant risk at the
project site.
5.0 GEOTECHNICAL ENGINEERING
Presented herein is a general discussion of the geotechnical properties of the various soil types and the
analytic methods used in this report.
5.1. Material Properties
5.1.1. Excavation Characteristics
Based on our previous experience with similar projects near the subject site and the
information gathered in preparing this report, it is our opinion that the surficial soils and
old paralic deposits are readily excavatable with conventional grading equipment.
However, it should be anticipated that well cemented zones could be encountered within
the old paralic deposits that may be difficult to excavate. Specialized grading equipment
(large excavators, hoe rams, and/or bull dozers) may be necessary to efficiently excavate
these materials.
5.1.2. Compressibility
Surficial soils consisting of topsoil, fill and the upper highly weathered portion of old
paralic deposits are considered “moderately” compressible in their present condition. In
areas to receive settlement sensitive improvements these materials will require complete
removal prior to placement of fill, and where exposed at design grade. Compressibility of
the unweathered old paralic deposits is not a geotechnical design concern for the proposed
development.
5.1.3. Collapse Potential/Hydro-Consolidation
The hydro-consolidation process is a singular response to the introduction of water into
collapse-prone alluvial soils. Upon initial wetting, the soil structure and apparent strength
are altered, and a virtually immediate settlement response occurs. The unweathered old
paralic deposits are not considered prone to hydro-collapse.
5.1.4. Expansion Potential
Based on our laboratory testing and experience in the project area, it is anticipated that the
expansion potential of the onsite materials will generally vary from “very low” to
“medium” with the majority of onsite materials in the “very low to low” range. Post-
grading testing should be conducted to define as-graded expansive soil characteristics. The
results of those tests and the final as-graded conditions will govern design of foundations
and driveway sections.
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5.1.5. Chemical and Resistivity Test Results
The test results from a sample collected during the current investigation indicated a sulfate
concentration that corresponds to a negligible (S0 – not applicable) sulfate exposure when
classified in accordance with ACI 318. The onsite soils are expected to be corrosive to
ferrous metals.
5.1.6. Pavement Support Characteristics
Compacted fill derived from onsite soils is expected to possess moderate pavement support
characteristics. Pavement design recommendations should be based on the R-value of the
compacted subgrade soils and can be provided, if required.
5.1.7. Shear Strength
Shear strength testing was conducted by AGS (Appendix C). The shear strengths that were
used by AGS for design are presented in the following table.
TABLE 5.1.7
Shear Strengths Used for Design
Material Cohesion
(psf)
Friction Angle
(degrees)
Moist Density
(pcf)
Compacted Fill – afc 100 30 130
Old Paralic Deposits – Qop2-4 200 32 125
5.1.8. Earthwork Adjustments
The onsite soils are expected to undergo a volume change when excavated and utilized as
a fill material. In an effort to balance earthwork quantities, the following volume
adjustments can be utilized. These numbers are considered approximate and should be
refined during grading when actual conditions are better defined. Contingencies should be
made to adjust the earthwork balance during grading if these numbers are adjusted.
TABLE 5.1.8
RECOMMENDED EARTHWORK ADJUSTMENTS
Geologic Unit Adjustment Factor
Topsoil and Artificial fill Shrink 5 – 15%
Old Paralic Deposits (Qop2-4) Bulk 0 – 3%
5.2. Analytical Methods
5.2.1. Bearing Capacity
Ultimate bearing capacity and shoring design values were obtained using the graphs and
formulas presented in NAVFAC DM-7.1. Allowable bearing was determined by applying
a factor of safety of at least three to the ultimate bearing capacity.
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5.2.2. Lateral Earth Pressures
Static lateral earth pressures were calculated using Rankine methods for active and passive
cases. If it is desired to use Coulomb forces, a separate analysis specific to the application
can be conducted.
6.0 GRADING AND SHORING RECOMMENDATIONS
Based on the information provided herein, the proposed project is considered feasible from a geotechnical
standpoint provided the conclusions and recommendations presented herein are incorporated into the design
and construction of the project.
6.1. Earthwork Recommendations
All grading should be accomplished under the observation and testing of the project soils engineer
and engineering geologist or their authorized representative in accordance with the
recommendations contained in the approved geotechnical reports, the Grading Specifications
contained in Appendix D, the project specifications, and the Building Code. Prior to fill placement,
the bottoms of all removal areas should be observed and approved by the engineering
geologist/soils engineer or their authorized representative.
6.1.1. Site Preparation
Existing vegetation, trash, debris, and other deleterious materials should be removed and
wasted from the site prior to commencing removal of unsuitable soils and placement of
compacted fill materials. Additionally, all pre-existing foundation elements and
underground improvements (e.g. utilities, storage tanks, etc.) should be removed and
wasted off-site. Abandoned utilities or storage tanks should be removed and/or abandoned
in accordance with local regulations.
6.1.2. Removals
Topsoil, artificial fill, and highly weathered old paralic deposits are considered to be
compressible in their current condition and should be removed in areas to receive fill and
where settlement sensitive improvements are planned. Detailed plans are not available at
this time and therefore the exact extent of required removals are unknown. In general, it is
anticipated that unsuitable soil removals will be on the order of 2 to 5 feet deep. Localized
areas may require deeper removals. The extent of removals can best be determined in the
field during grading when observation and evaluation can be performed by the soil engineer
and/or engineering geologist. Soils removed during remedial grading will be suitable for
reuse in compacted fills provided they are properly moisture conditioned and do not contain
deleterious materials.
6.2. Earthwork Considerations
6.2.1. Compaction Standards
All fills should be compacted to at least 90 percent of the maximum dry density as
determined by ASTM D1557. All loose and or deleterious soils should be removed to
expose firm native soils or bedrock. Prior to the placement of fill, the upper 6 to 8 inches
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should be ripped, moisture conditioned to optimum moisture or slightly above optimum,
and compacted to a minimum of 90 percent of the maximum dry density (ASTM D1557).
Fill should be placed in thin (6 to 8-inch) lifts, moisture conditioned to optimum moisture
or slightly above, and compacted to 90 percent of the maximum dry density (ASTM
D1557) until the desired grade is achieved.
6.2.2. Benching
Where the natural slope is steeper than 5-horizontal to 1-vertical and where determined by
the Geotechnical Consultant, compacted fill material shall be keyed and benched into
competent materials.
6.2.3. Mixing and Moisture Control
In order to prevent layering of different soil types and/or different moisture contents,
mixing and moisture control of materials will be necessary. The preparation of the earth
materials through mixing and moisture control should be accomplished prior to and as part
of the compaction of each fill lift. Water trucks or other water delivery means may be
necessary for moisture control. Discing may be required when either excessively dry or
wet materials are encountered.
6.2.4. Import Soils
Import soils, if required, should consist of clean, structural quality, compactable materials
similar to the on-site soils and should be free of trash, debris or other objectionable
materials. Import soils should be tested and approved by the Geotechnical Consultant prior
to importing. At least three working days should be allowed in order for the geotechnical
consultant to sample and test the potential import material.
6.3. Temporary Excavations
We anticipate that temporary, shallow excavations with vertical side slopes less than 4 feet high
will generally be stable. Deeper excavations should be sloped back at an inclination of 1.5:1
(horizontal: vertical). Personnel from AGS should observe the excavation so that any necessary
modifications based on variations in the encountered soil conditions can be made. All applicable
safety requirements and regulations, including CalOSHA requirements, should be met.
Where sloped excavations are created, the tops of the slopes should be barricaded so that vehicles
and storage loads do not encroach within 10 feet of the tops of the excavated slopes. A greater
setback may be necessary when considering heavy vehicles, such as concrete trucks and cranes.
AGS should be advised of such heavy vehicle loadings so that specific setback requirements can
be established. If the temporary construction slopes are to be maintained during the rainy season,
berms are recommended to be graded along the tops of the slopes in order to prevent runoff water
from entering the excavation and eroding the slope faces.
Vertical excavations greater than 4 feet high will require temporary shoring/shielding of the
subgrade soils. If temporary shoring becomes necessary, design recommendations can be provided
at that time.
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6.4. Utility Trench Backfill
Utility trench backfill should be compacted to at least 90 percent of maximum dry density (95
percent if below structural improvements) as determined by ASTM D1557. Onsite soils will not
be suitable for use as bedding material but will generally be suitable for use in backfill, provided
oversized and deleterious materials are removed. Compaction should be accomplished by
mechanical means. Jetting of native soils will not be acceptable.
6.5. Flatwork Subgrade Preparation
The upper one foot of subgrade below exterior slabs, sidewalks, patios, etc. should be compacted
to a minimum of 90 percent (95 percent below driveways) of the maximum dry density as
determined by ASTM D1557. The subgrade below exterior slabs, sidewalks, driveways, patios,
etc. should be moisture conditioned to a minimum of 110 percent of optimum moisture content
prior to concrete placement.
7.0 CONCLUSIONS AND DESIGN RECOMMENDATIONS
Construction of the proposed project is considered feasible, from a geotechnical standpoint, provided that
the conclusions and recommendations presented herein are incorporated into the design and construction
of the project. As with all projects, changes in observed conditions may result in alternative construction
techniques and/or possible delays. The contractor should be aware of these possibilities and provide
contingencies in his bids to account for them.
7.1. Structural Design
The site is mantled by a thin veneer of surficial soils which we anticipate will be removed to expose
formational materials that possess favorable geotechnical qualities. It is anticipated that the
majority of the onsite soils will generally vary from "Very Low" to "Medium" in expansion
potential when tested in general accordance with ASTM D 4829.
7.1.1. Foundation Design
The proposed single-family residential structure can be supported on conventional shallow
foundations and a slab-on-grade system bearing on competent formation materials or
compacted fill, as discussed above. The design of foundation systems should be based on
as-graded conditions as determined after grading completion. The following values may
be used in preliminary foundation design:
Allowable Bearing: 2500 psf.
Lateral Bearing: 250 lbs./sq.ft. at a depth of 12 inches plus
125 lbs./sq.ft. for each additional 12 inches
embedment to a maximum of 2500 lbs./sq.ft.
Sliding Coefficient: 0.35
Settlement: Total = 1 inch
Differential = 1/2 inch in 20 feet
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The above values may be increased as allowed by Code to resist transient loads such as
wind or seismic. Based on anticipated preliminary expansion potential of “Very Low” to
“Medium” for the onsite soil and information supplied by the CBC-2016, additional
foundation design recommendations are provided in Table 7.1.1.
TABLE 7.1.1
FOUNDATION DESIGN RECOMMENDATIONS
Expansion Potential Very Low to Low (Cat. I) Medium (Cat. II)
Footing Depth Below Lowest Adjacent Finish Grade
One-Story 12 inches 18 inches
Two-Story 18 inches 18 inches
Footing Width
One-Story 12 inches 12 inches
Two-Story 15 inches 15 inches
Footing Reinforcement
One-Story No. 4 rebar, one (1) on top and one
(1) on bottom
No. 4 rebar, two (2) on top and two
(2) on bottom or No. 5 rebar one (1)
on top and one (1) on bottom
Two-Story No. 4 rebar, one (1) on top and one
(1) on bottom
No. 4 rebar, two (2) on top and two
(2) on bottom or No. 5 rebar one (1)
on top and one (1) on bottom
Slab Thickness 5 inches (actual) 5 inches (actual)
Slab Reinforcement No. 3 rebar spaced 15 inches on
center, each way
No. 3 rebar spaced 12 inches on
center, each way
Slab Subgrade
Moisture
Minimum of optimum moisture
prior to placing concrete.
Minimum of 120% of optimum
moisture 24 hours prior to placing
concrete.
Footing Embedment Next to Swales and Slopes
If exterior footings adjacent to drainage swales are to exist within five (5) feet horizontally of the swale, the
footing should be embedded sufficiently to assure embedment below the swale bottom is maintained.
Footings adjacent to slopes should be embedded such that a least seven (7) feet are provided horizontally from
edge of the footing to the face of the slope.
Garages
A grade beam reinforced continuously with the garage footings shall be constructed across the garage
entrance, tying together the ends of the perimeter footings and between individual spread footings. This grade
beam should be embedded at the same depth as the adjacent perimeter footings. A thickened slab, separated
by a cold joint from the garage beam, should be provided at the garage entrance. Minimum dimensions of
the thickened edge shall be six (6) inches deep. Footing depth, width and reinforcement should be the same
as the structure. Slab thickness, reinforcement and underslab treatment should be the same as the structure.
Isolated Spread Footings
Isolated spread footings should be embedded a minimum of 18 inches below lowest adjacent finish grade and
should at least 24 inches wide. A grade beam should also be constructed for interior and exterior spread
footings and should be tied into the structure in two orthogonal directions, footing dimensions and
reinforcement should be similar to the aforementioned continuous footing recommendations. Final depth,
width and reinforcement should be determined by the structural engineer
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7.1.2. Moisture and Vapor Barrier
A moisture and vapor retarding system should be placed below the slabs-on-grade in
portions of the structure considered to be moisture sensitive. The retarder should be of
suitable composition, thickness, strength and low permeance to effectively prevent the
migration of water and reduce the transmission of water vapor to acceptable levels.
Historically, a 10-mil plastic membrane, such as Visqueen, placed between one to four
inches of clean sand, has been used for this purpose. More recently Stego® Wrap or similar
underlayments have been used to lower permeance to effectively prevent the migration of
water and reduce the transmission of water vapor to acceptable levels. The use of this
system or other systems, materials or techniques can be considered, at the discretion of the
designer, provided the system reduces the vapor transmission rates to acceptable levels.
7.2. Conventional Retaining Walls
The following earth pressures are recommended for the design of proposed retaining basement
walls onsite. Earth pressures for both compacted fill and the Old Paralic Deposits are provided
below:
Static Case
Compacted Fill (phi = 30°, unit wt. = 130 pcf)
Rankine Equivalent Fluid
Level Backfill Coefficients Pressure (psf/lin.ft.)
Coefficient of Active Pressure: Ka = 0.33 43
Coefficient of Passive Pressure: Kp = 3.00 390
Coefficient of at Rest Pressure: Ko = 0.50 65
Rankine Equivalent Fluid
2 : 1 Backfill Coefficients Pressure (psf/lin.ft.)
Coefficient of Active Pressure: Ka = 0.54 70
Coefficient of At Rest Pressure: Ko = 0.90 118
Old Paralic Deposits (phi = 32°, unit wt. = 125pcf)
Rankine Equivalent Fluid
Level Backfill Coefficients Pressure (psf/lin.ft.)
Coefficient of Active Pressure: Ka = 0.31 38
Coefficient of Passive Pressure: Kp = 3.25 407
Coefficient of at Rest Pressure: Ko = 0.47 59
Rankine Equivalent Fluid
2 : 1 Backfill Coefficients Pressure (psf/lin.ft.)
Coefficient of Active Pressure: Ka = 0.47 59
Coefficient of At Rest Pressure: Ko = 0.85 106
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Seismic Case
In addition to the above static pressures, unrestrained retaining walls located should be designed to
resist seismic loading as required by the 2016 CBC. The seismic load can be modeled as a thrust
load applied at a point 0.6H above the base of the wall, where H is equal to the height of the wall.
This seismic load (in pounds per lineal foot of wall) is represented by the following equation:
Pe = ⅜ *γ*H2 *kh
Where: Pe = Seismic thrust load
H = Height of the wall (feet)
γ = soil density = 125 pounds per cubic foot (pcf)
kh = seismic pseudostatic coefficient = 0.5 * peak horizontal
ground acceleration (PGAm)
Walls should be designed to resist the combined effects of static pressures and the above seismic
thrust load.
A bearing value of 2500 psf may be used for design of retaining walls bearing on compacted fill or
competent formational mateirals. A value of 0.35 may be used to model the frictional between the
soil and concrete. For sliding passive pressure both passive and friction can be combined to a
maximum of 2/3 the total.
Retaining wall footings should be designed to resist the lateral forces by passive soil resistance
and/or base friction as recommended for foundation lateral resistance. To relieve the potential for
hydrostatic pressure wall backfill should consist of a free draining backfill (sand equivalent “SE”
>20) and a heel drain should be constructed. The heel drain should be place at the heel of the wall
and should consist of a 4-inch diameter perforated pipe (SDR35 or SCHD 40) surrounded by 1
cubic foot of crushed rock (3/4-inch) per lineal foot, wrapped in filter fabric (Mirafi® 140N or
equivalent).
Proper drainage devices should be installed along the top of the wall backfill, which should be
properly sloped to prevent surface water ponding adjacent to the wall. In addition to the wall
drainage system, for building perimeter walls extending below the finished grade, the wall should
be waterproofed and/or damp-proofed to effectively seal the wall from moisture infiltration through
the wall section to the interior wall face.
The wall should be backfilled with granular soils placed in loose lifts no greater than 8-inches thick,
at or near optimum moisture content, and mechanically compacted to a minimum 90 percent
relative compaction as determined by ASTM Test Method D1557. Flooding or jetting of backfill
materials generally do not result in the required degree and uniformity of compaction and,
therefore, is not recommended. The soils engineer or his representative should observe the retaining
wall footings, backdrain installation and be present during placement of the wall backfill to confirm
that the walls are properly backfilled and compacted.
7.3. Concrete Design
Testing by AGS indicated that the onsite soils have low concentrations of soluble sulfate,
corresponding to an S0 exposure class when classified in accordance with ACI 318. Final
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determination will be based upon testing of near surface soils obtained at the conclusion of grading.
Some fertilizers have been known to leach sulfates into soils otherwise containing "negligible"
sulfate concentrations, therefore Type II/V cement is recommended for concrete in contact with
soil.
7.4. Corrosion
The onsite soils are expected to be corrosive to buried metallic materials. AGS recommends
minimally that the current standard of care be employed for protection of metallic construction
materials in contact with onsite soils and consultation with a corrosion engineer to determine
specifications for protection of construction materials. Steel reinforcement in contact with onsite
soils should be protected with an epoxy coating, adequate concrete cover, or other approved
methods as detailed by the structural engineer.
7.5. Site Drainage
Final site grading should assure positive drainage away from structures. Planter areas should be
provided with area drains to transmit irrigation and rainwater away from structures. The use of
gutters and down spouts to carry roof drainage well away from structures is recommended. Raised
planters should be provided with a positive means to remove water through the face of the
containment wall.
7.6. Exterior Flatwork
Concrete flatwork not subject to vehicular traffic loading should be designed utilizing 4-inch
minimum thickness. Consideration should be given to construct a thickened edge (scoop footing)
at the perimeter of slabs and walkways adjacent to landscape areas to minimize moisture variation
below these improvements. The thickened edge (scoop footing) should extend approximately 8
inches below concrete slabs and should be a minimum of 6 inches wide.
Weakened plane joints should be installed on walkways at intervals of approximately 6 to 8 feet.
Exterior slabs should be designed to withstand shrinkage of the concrete. Consideration should be
given to reinforcing any exterior flatwork.
8.0 FUTURE STUDY NEEDS
8.1. Construction Plans
Grading and construction plans have not yet been developed. The recommendations provided
herein are considered preliminary and subject to change based on the actual design. When
available, the geotechnical engineer should review detailed construction plans. The following plans
should be reviewed:
• Precise grading and utility plans
• Structural plans including foundation plans and retaining wall plans and
calculations.
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8.2. Observation During Construction
Continuous geologic and geotechnical observations, testing, and mapping should be provided
throughout site development. Additional near-surface samples should be collected by the
geotechnical consultant during grading and subjected to laboratory testing. Final design
recommendations should be provided in a grading report based on the observation and test results
collected during grading.
9.0 CLOSURE
The findings and recommendations in this report are based on the specific excavations, observations, and
tests results obtained during this investigation. The findings are based on the review and interpretation of
the field and laboratory data combined with an interpolation and extrapolation of conditions between and
beyond the exploratory excavations. Services performed by AGS have been conducted in a manner
consistent with that level of care and skill ordinarily exercised by members of the profession currently
practicing in the same locality under similar conditions. No other representation, either expressed or
implied, and no warranty or guarantee is included or intended.
The recommendations presented in this report are based on the assumption that an appropriate level of field
review will be provided by geotechnical engineers and engineering geologists who are familiar with the
design and site geologic conditions. That field review shall be sufficient to confirm that geotechnical and
geologic conditions exposed during grading are consistent with the geologic representations and
corresponding recommendations presented in this report. If the project description varies from what is
described in this report, AGS must be consulted regarding the applicability of, and the necessity for, any
revisions to the recommendations presented herein. AGS accepts no liability for use of its recommendations
if AGS is not consulted regarding any project changes.
The data, opinions, and recommendations of this report are applicable to the specific design of this project
as discussed in this report. They have no applicability to any other project or to any other location, and any
and all subsequent users accept any and all liability resulting from any use or reuse of the data, opinions,
and recommendations without the prior written consent of AGS.
AGS has no responsibility for construction means, methods, techniques, sequences, or procedures, or for
safety precautions or programs in connection with the construction, for the acts or omissions of the
CONTRACTOR, or any other person performing any of the construction, or for failure of any of them to
carry out the construction in accordance with the final design drawings and specifications.
ADVANCED GEOTECHNICAL SOLUTIONS, INC.
APPENDIX A
REFERENCES
December 31, 2019 Page A-1
P/W 1909-11 Report No. 1909-11-B-2
ADVANCED GEOTECHNICAL SOLUTIONS, INC.
REFERENCES
American Concrete Institute, 2014, Building Code Requirements for Structural Concrete (ACI318M-14)
and Commentary (ACI 318RM-11), ACI International, Farmington Hills, Michigan.
American Society for Testing and Materials (2018), Annual Book of ASTM Standards, Section 4,
Construction, Volume 04.08, Soil and Rock (I), ASTM International, West Conshohocken,
Pennsylvania.
California Building Standards Commission, 2016, California Building Code, Title 24, Part 2, Volumes 1
and 2.
City of San Diego, 2008, Seismic Safety Study, Sheet 20.
Jennings, C.W., 1994, Fault Activity Map of California and Adjacent Areas: California Geological Survey,
California Geologic Data Map No. 6, Scale 1:750,000.
Kennedy, M.P., and Tan, S.S., 2007, Geologic Map of the Oceanside 30' x 60' Quadrangle, California,
California Geological Survey, Preliminary Geologic Maps, Scale 1:100,000.
SEAOC/OSHPD, 2019, ASCE 7-10 Seismic Design Maps, https://seismicmaps.org/
United States Geological Survey, 2019, Unified Hazards Tool,
https://earthquake.usgs.gov/hazards/interactive/
ADVANCED GEOTECHNICAL SOLUTIONS, INC.
APPENDIX B
BORING LOGS
Artificial Fill - Undocumented (afu)
Silty fine- to medium-grained SAND with trace Clay, dark
brown to dark yellow brown, slightly moist, loose; occasional
roots
Old Paralic Deposits (Qop)
Silty fine- to coarse-grained SAND, dark gray brown, dry to
slightly moist, dense; slightly micaceous
@ 5.0 ft., very dense; minor iron oxide staining
@ 7.5., Silty fine-grained SAND with trace Clay, light gray
brown to olive, slightly moist, very dense; abundant iron
oxide staining, occasional manganese oxide nodules
@ 10.0 ft., mostly fine-grained with some coarse-grained,
increased Clay content, yellow brown to gray brown to olive
brown; rock fragments in sample, gravel to cobble lense
@ 15.0 ft., increased Silt content, dark yellow brown to
orange brown
@ 20.0 ft., Sandy SILT to Silty SAND, fine-grained, light
yellow brown, slightly moist to moist, stiff to medium dense
Total depth = 21.5 feet
No groundwater encountered
Backfilled with bentonite and cement grout
7-13-21
(34)
17-26-40
(66)
11-24-35
(59)
50
15-21-24
(45)
10-12-15
(27)
BU
MC
MC
MC
MC
SPT
SPT
111
129
118
3.0
5.6
6.1
3.4
15
49
39
SM
SM
EI,CHEM
SHEAR
NOTES
GROUND ELEVATION 81.8 ft
LOGGED BY SS
DRILLING METHOD Hollow Stem Auger
HOLE SIZE 8
DRILLING CONTRACTOR Baja Exploration GROUND WATER LEVELS:
CHECKED BY PJD
DATE STARTED 12/31/19 COMPLETED 12/31/19
AT TIME OF DRILLING ---
AT END OF DRILLING ---
AFTER DRILLING ---
MATERIAL DESCRIPTION
BL
O
W
CO
U
N
T
S
(N
V
A
L
U
E
)
GR
A
P
H
I
C
LO
G
DE
P
T
H
(f
t
)
0
5
10
15
20
SA
M
P
L
E
T
Y
P
E
NU
M
B
E
R
LI
Q
U
I
D
LI
M
I
T
PL
A
S
T
I
C
LI
M
I
T
PL
A
S
T
I
C
I
T
Y
IN
D
E
X
ATTERBERG
LIMITS
PL
A
S
T
I
C
I
T
Y
IN
D
E
X
DR
Y
U
N
I
T
W
T
.
(p
c
f
)
MO
I
S
T
U
R
E
CO
N
T
E
N
T
(
%
)
SA
T
U
R
A
T
I
O
N
(
%
)
FI
N
E
S
C
O
N
T
E
N
T
(%
)
US
C
S
OT
H
E
R
T
E
S
T
S
PAGE 1 OF 1
BORING NUMBER B-1
AG
S
B
O
R
I
N
G
L
O
G
V
2
-
G
I
N
T
S
T
D
U
S
L
A
B
.
G
D
T
-
1
/
2
2
/
2
0
1
5
:
2
5
-
Z
:
\
P
R
O
J
E
C
T
F
I
L
E
S
\
1
9
0
1
-
0
3
F
O
R
R
E
S
T
E
R
R
E
S
I
D
E
N
C
E
\
L
O
G
S
A
N
D
L
A
B
\
1
9
0
1
-
0
3
L
O
G
S
.
G
P
J
CLIENT John Forester
PROJECT NUMBER 1901-03
PROJECT NAME 4464 Adams Street
PROJECT LOCATION Carlsbad, CA
•._ ~AGS
AOVlN ED GEOTECHNIC.AL Ol 10 , l""C
:··::-.·.
:··:• .. ·.
--:":~·-· ·::-.·.
·._. ....
:··::-.·.
:··::-.·. -· -:: :· ,•
·:·-.·.
:··::-.·.
-····:• .. ·.
-:: :· ,•
·::-.·.
:··::-.· . . . ,• --:::.·,:: :··::-.·.
-:: :· ,•
·:·-·.
M
Artificial Fill - Undocumented (afu)
Silty fine- to medium-grained SAND, dark brown to dark
gray brown, moist, loose; occasional roots, piece of wood
Old Paralic Deposits (Qop)
Silty fine- to coarse-grained SAND trace Clay, dark gray
brown to dark red brown, moist, dense; slightly micaceous
@ 9.0 ft., yellow brown to red brown; micaceous
Total depth = 21.5 feet
No groundwater encountered
Backfilled with bentonite and cement grout
6-6-12
(18)
6-10-15
(25)
10-12-18
(30)
8-15-16
(31)
7-16-19
(35)
9-13-17
(30)
BU
MC
MC
MC
SPT
MC
SPT
108
117
114
113
3.8
4.9
3.8
4.3
18
30
21
24
SM
SM
MAX,REMOLD
SHEAR
NOTES
GROUND ELEVATION 82.5 ft
LOGGED BY SS
DRILLING METHOD Hollow Stem Auger
HOLE SIZE 8
DRILLING CONTRACTOR Baja Exploration GROUND WATER LEVELS:
CHECKED BY PJD
DATE STARTED 12/31/19 COMPLETED 12/31/19
AT TIME OF DRILLING ---
AT END OF DRILLING ---
AFTER DRILLING ---
MATERIAL DESCRIPTION
BL
O
W
CO
U
N
T
S
(N
V
A
L
U
E
)
GR
A
P
H
I
C
LO
G
DE
P
T
H
(f
t
)
0
5
10
15
20
SA
M
P
L
E
T
Y
P
E
NU
M
B
E
R
LI
Q
U
I
D
LI
M
I
T
PL
A
S
T
I
C
LI
M
I
T
PL
A
S
T
I
C
I
T
Y
IN
D
E
X
ATTERBERG
LIMITS
PL
A
S
T
I
C
I
T
Y
IN
D
E
X
DR
Y
U
N
I
T
W
T
.
(p
c
f
)
MO
I
S
T
U
R
E
CO
N
T
E
N
T
(
%
)
SA
T
U
R
A
T
I
O
N
(
%
)
FI
N
E
S
C
O
N
T
E
N
T
(%
)
US
C
S
OT
H
E
R
T
E
S
T
S
PAGE 1 OF 1
BORING NUMBER B-2
AG
S
B
O
R
I
N
G
L
O
G
V
2
-
G
I
N
T
S
T
D
U
S
L
A
B
.
G
D
T
-
1
/
2
2
/
2
0
1
5
:
2
5
-
Z
:
\
P
R
O
J
E
C
T
F
I
L
E
S
\
1
9
0
1
-
0
3
F
O
R
R
E
S
T
E
R
R
E
S
I
D
E
N
C
E
\
L
O
G
S
A
N
D
L
A
B
\
1
9
0
1
-
0
3
L
O
G
S
.
G
P
J
CLIENT John Forester
PROJECT NUMBER 1901-03
PROJECT NAME 4464 Adams Street
PROJECT LOCATION Carlsbad, CA
•._ ~AGS
AOVlN ED GEOTECHNIC.AL Ol 10 , l""C
-:: :· .• ..... .-.
:··::-.·.
-:: :· .•
·::-.· .
. . . • -:: :· ,•
-:··:·-.·.
:··::-.·.
-:: :· ,•
·:·-.· .
. . ,• --:::·.:: :··::-.·.
:··::-.·.
-:: :· ,•
·::-.·. --.. ·· -:: :· ,•
//\]
Artificial Fill - Undocumented (afu)
Silty fine- to medium-grained SAND with trace Clay, dark
gray brown, moist to very moist, loose
Old Paralic Deposits (Qop)
Silty fine- to coarse-grained SAND, dark gray brown to dark
yellow brown, dry to slightly moist, dense
@ 5.0 ft., fine- to medium grained, dense; micaceous
@ 10.0 ft., yellow brown to orange brown
@ 20.0 ft., light yellow brown
Total depth = 21.5 feet
No groundwater encountered
Backfilled with bentonite and cement grout
13-23-24
(47)
9-18-22
(40)
11-24-31
(55)
10-16-20
(36)
MC
SPT
MC
SPT
111
4.3
3.3 17
SM
SM
NOTES
GROUND ELEVATION 94 ft
LOGGED BY SS
DRILLING METHOD Hollow Stem Auger
HOLE SIZE 8
DRILLING CONTRACTOR Baja Exploration GROUND WATER LEVELS:
CHECKED BY PJD
DATE STARTED 12/31/19 COMPLETED 12/31/19
AT TIME OF DRILLING ---
AT END OF DRILLING ---
AFTER DRILLING ---
MATERIAL DESCRIPTION
BL
O
W
CO
U
N
T
S
(N
V
A
L
U
E
)
GR
A
P
H
I
C
LO
G
DE
P
T
H
(f
t
)
0
5
10
15
20
SA
M
P
L
E
T
Y
P
E
NU
M
B
E
R
LI
Q
U
I
D
LI
M
I
T
PL
A
S
T
I
C
LI
M
I
T
PL
A
S
T
I
C
I
T
Y
IN
D
E
X
ATTERBERG
LIMITS
PL
A
S
T
I
C
I
T
Y
IN
D
E
X
DR
Y
U
N
I
T
W
T
.
(p
c
f
)
MO
I
S
T
U
R
E
CO
N
T
E
N
T
(
%
)
SA
T
U
R
A
T
I
O
N
(
%
)
FI
N
E
S
C
O
N
T
E
N
T
(%
)
US
C
S
OT
H
E
R
T
E
S
T
S
PAGE 1 OF 1
BORING NUMBER B-3
AG
S
B
O
R
I
N
G
L
O
G
V
2
-
G
I
N
T
S
T
D
U
S
L
A
B
.
G
D
T
-
1
/
2
2
/
2
0
1
5
:
2
5
-
Z
:
\
P
R
O
J
E
C
T
F
I
L
E
S
\
1
9
0
1
-
0
3
F
O
R
R
E
S
T
E
R
R
E
S
I
D
E
N
C
E
\
L
O
G
S
A
N
D
L
A
B
\
1
9
0
1
-
0
3
L
O
G
S
.
G
P
J
CLIENT John Forester
PROJECT NUMBER 1901-03
PROJECT NAME 4464 Adams Street
PROJECT LOCATION Carlsbad, CA
•._ ~AGS
AOVlN ED GEOTECHNIC.AL Ol 10 , l""C
:··::-.·.
:··:• .. ·.
--:":~·-· ·::-.·.
·._. ....
:··::-.·.
:··::-.·. -· -:: :· ,•
·:·-.·.
:··::-.·.
-····:• .. ·.
-:: :· ,•
·::-.·.
:··::-.· . . . ,• --:::.·,:: :··::-.·.
-:: :· ,•
·:·-·.
ADVANCED GEOTECHNICAL SOLUTIONS, INC.
APPENDIX C
LABORATORY TEST RESULTS
December 31, 2019 Page C-1
P/W 1909-11 Report No. 1909-11-B-2
ADVANCED GEOTECHNICAL SOLUTIONS, INC.
APPENDIX C
LABORATORY TESTING
Classification
Soils were visually and texturally classified in accordance with the Unified Soil Classification System
(USCS) in general accordance with ASTM D2488. Soil classifications are indicated on the boring logs
in Appendix B.
Expansion Index Test
The expansion index of selected materials was evaluated in general accordance with ASTM D 4829.
Specimens were molded under a specified compactive energy at approximately 50 percent saturation
(plus or minus 1 percent). The prepared 1 inch thick by 4-inch diameter specimens were loaded with a
surcharge of 144 pounds per square foot and were inundated with tap water. Readings of volumetric
swell were made for a period of 24 hours. The results of these tests are presented on Figure C-1.
Modified Proctor Density
The maximum dry density and optimum moisture content of a selected representative soil sample was
evaluated using the Modified Proctor method in general accordance with ASTM D1557. The results
of these tests are summarized on Figure C-2.
Direct Shear
Direct shear tests were performed on undisturbed and remolded samples in general accordance with
ASTM D3080 to evaluate the shear strength characteristics of selected materials. The samples were
inundated during shearing to represent adverse field conditions. The results are shown on Figures C-3
though C-5.
Soil Corrosivity
Soil pH, and resistivity testing was performed on a selected sample in general accordance with
California Test (CT)643. The chloride content of a selected sample was evaluated in general
accordance with CT422. The sulfate content of a selected sample was evaluated in general accordance
with CT417. The test results are presented on Figure C-6.
EXPANSION INDEX - ASTM D4829 AGS FORM E-6
Project Name: 4465 Adams St Excavation/Tract: B-1
Location: Carlsbad Depth/Lot: 0 - 2.5'
P/W: 1901-03 Description: Drk Brn SM
Date: 1/6/20 Tested by: JR
Checked by: FV
Expansion Index - ASTM D4829
Initial Dry Density (pcf): 119.5
Initial Moisture Content (%): 7.6
Initial Saturation (%): 49.8
Final Dry Density (pcf): 119.6
Final Moisture Content (%): 14.2
Final Saturation (%): 93.8
Expansion Index: 0
Potential Expansion: Very Low
ASTM D4829 - Table 5.3
Expansion Index
0 - 20
21 - 50
51 - 90
91 - 130
>130 Very High
ADVANCED GEOTECHNICAL SOLUTIONS, INC.
Potential Expansion
Very Low
Low
Medium
High
1901-03_EI_B-1_0.0-2.5 ft_01-06-2020_JR FIGURE C-1
MAXIMUM DENSITY - ASTM D1557 AGS FORM E-8
Project Name: 4464 Adams St Excavation: B-2
Location: Carlsbad Depth: 0 - 3 ft.
P/W No.: 1901-03 Soil Type: Dark Brn. SC-SM
Date:Tested by: JR
Checked by: PJ
Method: A Oversize Retained: 0 %
Point No.1 2 3 4
Dry Density (pcf)124.2 129.0 131.5 126.9
Moisture Content (%)5.7 7.7 9.5 11.7
Corrected Max. Dry Density 131.5 pcf Corrected Moisture 9.5 %
Max. Dry Density 131.5 pcf Optimum Moisture 9.5 %
ADVANCED GEOTECHNICAL SOLUTIONS, INC.
01-2020
100.0
105.0
110.0
115.0
120.0
125.0
130.0
135.0
140.0
0.0 5.0 10.0 15.0 20.0 25.0 30.0
DR
Y
D
E
N
S
I
T
Y
(
p
c
f
)
MOISTURE (%)
MAXIMUM DENSITY CURVE
Test Curve
Zero Air Voids Curves
SG=2.6
SG=2.7
SG=2.8
FIGURE C-2
I ,_ I..----~
J"
-)
~ ,
•
'---,_.__ -, ,_.__
" .. '
1, ' I,. ',t-,'""'\: t~ 1. '\
Project Name: 4464 Adams St Excavation: B-2
Location: Carlsbad Depth: 0-3 ft
Project No.: 1901-03 Tested by: FV
Date:Reviewed by:
Samples Tested 1 2 3 Soil Type: Dark Brn SC-SM
Intial Moisture (%) 9.5 9.5 9.5 Test: Remolded 90%
Initial Dry Density (pcf) 118.3 118.3 118.3 Method: Drained
Normal Stress (psf) 1000 2000 4000 Consolidation: Yes
Peak Shear Stress (psf) 912 1452 2700 Saturation: Yes
Ult. Shear Stress (psf) 696 1332 2472 Shear Rate (in/min):0.01
Strength Parameters Peak Ultimate
Friction Angle, phi (deg)31 30
Cohesion (psf)288 126
ADVANCED GEOTECHNICAL SOLUTIONS, INC.
DIRECT SHEAR - ASTM D3080
1/21/2020
‐0.02
‐0.01
0.00
0.01
0.02
0.03
0.04
0.05
0.00 0.10 0.20 0.30
Ve
r
t
i
c
a
l
De
f
o
r
m
a
t
i
o
n
(i
n
)
Displacement (in)
Vertical Deformation v. Displacement
4000
2000
10000
500
1000
1500
2000
2500
3000
0.00 0.10 0.20 0.30
Sh
e
a
r
St
r
e
s
s
(p
s
f
)
Displacement (in)
Shear Stress v. Displacement
4000
2000
1000
0
500
1000
1500
2000
2500
3000
0 500 1000 1500 2000 2500 3000 3500 4000 4500
Sh
e
a
r
St
r
e
s
s
(p
s
f
)
Normal Stress (psf)
Peak
Peak
Ultimate
Ultimate
FIGURE C-3
-
1-I I 7 -
~
I_ I I _J c====----t-t-1
L
I
I
Project Name: 4464 Adams ST Excavation: B-1
Location: Carlsbad Depth: 8.5-9.0 ft
Project No.: 1901-03 Tested by: FV
Date:Reviewed by:
Samples Tested 1 2 3 Soil Type: Qop
Intial Moisture (%) 6.1 6.1 6.1 Test: Undisturbed
Initial Dry Density (pcf) 116.6 118.0 122.5 Method: Drained
Normal Stress (psf) 1000 2000 4000 Consolidation: Yes
Peak Shear Stress (psf) 1080 1692 3456 Saturation: Yes
Ult. Shear Stress (psf) 744 1416 3084 Shear Rate (in/min):0.01
Strength Parameters Peak Ultimate
Friction Angle, phi (deg)39 36
Cohesion (psf)198 0
ADVANCED GEOTECHNICAL SOLUTIONS, INC.
DIRECT SHEAR - ASTM D3080
1/7/2020
‐0.02
‐0.01
0.00
0.01
0.02
0.03
0.04
0.05
0.00 0.10 0.20 0.30
Ve
r
t
i
c
a
l
De
f
o
r
m
a
t
i
o
n
(i
n
)
Displacement (in)
Vertical Deformation v. Displacement
4000
2000
10000
500
1000
1500
2000
2500
3000
3500
4000
0.00 0.10 0.20 0.30
Sh
e
a
r
St
r
e
s
s
(p
s
f
)
Displacement (in)
Shear Stress v. Displacement
4000
2000
1000
0
500
1000
1500
2000
2500
3000
3500
4000
4500
0 500 1000 1500 2000 2500 3000 3500 4000 4500
Sh
e
a
r
St
r
e
s
s
(p
s
f
)
Normal Stress (psf)
Peak
Peak
Ultimate
Ultimate
FIGURE C-4
••••• ••••••••••• ····••o,,, ················
------
------j,1/ ----7
;r 1-----I
Project Name: 4464 Adams St Excavation: B-2
Location: Carlsbad Depth: 10-10.5 ft
Project No.: 1901-03 Tested by: FV
Date:Reviewed by:
Samples Tested 1 2 3 Soil Type: Qop
Intial Moisture (%) 3.8 3.8 3.8 Test: Undisturbed
Initial Dry Density (pcf) 110.7 113.8 110.0 Method: Drained
Normal Stress (psf) 1000 2000 4000 Consolidation: Yes
Peak Shear Stress (psf) 840 1548 2724 Saturation: Yes
Ult. Shear Stress (psf) 672 1272 2484 Shear Rate (in/min):0.01
Strength Parameters Peak Ultimate
Friction Angle, phi (deg)32 31
Cohesion (psf)252 66
ADVANCED GEOTECHNICAL SOLUTIONS, INC.
DIRECT SHEAR - ASTM D3080
1/21/2020
‐0.02
‐0.01
0.00
0.01
0.02
0.03
0.04
0.05
0.00 0.10 0.20 0.30
Ve
r
t
i
c
a
l
De
f
o
r
m
a
t
i
o
n
(i
n
)
Displacement (in)
Vertical Deformation v. Displacement
4000
2000
10000
500
1000
1500
2000
2500
3000
0.00 0.10 0.20 0.30
Sh
e
a
r
St
r
e
s
s
(p
s
f
)
Displacement (in)
Shear Stress v. Displacement
4000
2000
1000
0
500
1000
1500
2000
2500
3000
0 500 1000 1500 2000 2500 3000 3500 4000 4500
Sh
e
a
r
St
r
e
s
s
(p
s
f
)
Normal Stress (psf)
Peak
Peak
Ultimate
Ultimate
FIGURE C-5
··········· ··············
' f ,, ' , ! ,
--... -... __
/'---~------------------------------------------
II J
ANAHEIM TEST LAB, INC
196 Technology Drive, Unit D
Irvine, CA 92618
Phone (949)336-6544
DATE: 01/10/2020
Advanced Geotechnical Solutions, Inc.
485 Corporate Ave., Suite B P.O. NO.: Chain of Custody
Escondido, CA 92029
LAB NO.: C-3479
SPECIFICATION: CTM-417/422/643
MATERIAL: Soil
Project No.: 1901-03
Project: 4464 Adams Street
Date sampled: 01/06/2020
Location: B-1 @ 0’-2.5’
ANALYTICAL REPORT
CORROSION SERIES
SUMMARY OF DATA
pH SOLUBLE SULFATES SOLUBLE CHLORIDES MIN. RESISTIVITY
per CT. 417 per CT. 422 per CT. 643
ppm ppm ohm-cm
7.7 240 92 1,500
RESPECTFULLY SUBMITTED
________________________________
WES BRIDGER, LAB MANAGER
FIGURE C-6
Project:
P/W 1901-03
Report:Date:
Jan. 2020
PLATE 1
Geologic and Exploration Location Plan
1901-03-B-2
LEGEND:
Approximate location of exploratory
borings (, 2017)AGS
B-3
afu Artificial Fill - Undocumented
Old Paralic Deposits
(Bracketed where buried)
Santiago Formation
(Bracketed where buried)
Existing Grade/Structures
Proposed Grade/Structures
Approximate Location of Geologic
Contacts (Queried were uncertain)
Approximate location of geologic
cross sections
A A’
Qop
Tsa
B-1
B-2
B-3
?
?
?
afu
(Qop)
((Tsa))
Qop
(Tsa)
aTYOF
ENCINITAS
PROJECT
SITE 4
~~TO
I
VICINITY MAP
NOT TO SCALE
EX. WLY PR. N"LY SLY SLY
R/W R/W R/W
~I -----------=5=5•---------,1,--r-1 -PROJECT
I ~ ~s'
VARIES
~10'
VARIES
~20' 5' RIW DEDICATION ONLY
NO FRONTAGE IMPROVEMENTS
2% 2% -2% --
HIGHLAND DRIVE
NOT TO SCALE: RESIDENTIAL STREET
'"LY EX. PR. " £'LY £'LY ir½ R/W R/W 55' l----------""'-------------:-1
1
--;--PROJECT
25" JO'
I
I
~
VARIES 25'
17'
f J'
1 SAW CUT-LINE ~
ADAMS STREET
NOT TO SCALE RESIDENTIAL STREET
5' R/W OED/CATION
PROPOSED MINOR ROAD WIDENING
PROVIDE NEW CURB & GUTTER 17'
FROM C/L W/ J' GRADED BENCH
-..... __.
206-)80-38
----92
"' C, q
1
<tr
9J
PROPOSED
"' CIJRB & q GUTTER
~ --· -'-----· -·
---------
,._ -~/{'
RES!Df:NCE
,: -~
PAD=92.00
fT=92.6q
a a
20p-192-0S
PROPOSEO
2" HPPE
STORM \ TER CE
EXISnNc 1 O"
ACP WAIER IMJN owe 149-B
DRAIN
EXlsnNc 8" 11:'P
SEWER IMJN PER
DWG 149-8
'
r
a
..,
1./AJN
Rf:S1otNcE
'
92.0 TW
8 .O FG
' },'-10.0'
' '
206-192-07
.lllBI
... s-,
.. ------==== .. ==-::!.-==-==-== ..... _•·~:=:_-===~··==-
r
PREPARED BY=
Fusion Eng Tech
4231 Balboa Ave #619
Ban Diego CA
(619) 736-2800
20 0 20 40 60 c-----
SCALE 1 "= 20'
~ACS
ADVANCED GEOTECHNICAL SOLUTIONS, INC
APN:
206-192-08
LEGAL DESCRIPTION:
LOT 13 PER SUBDIVISON MAP 2152
EARTHWORK QUANTITIES:
C.Y. CUT
-C.Y. FILL
-C.Y. IMPORT
-C.Y. EXPORT
-C.Y. REMEDIAL
DMA CALCS:
EXISTING ROOF =1,290 S.F.
EXISTING HARDSCAPE=7,734 S.F.
PROPOSED ROOF=B,436 S.F.
PROPOSED HARDSCAPE=3,965 S.F.
NET INCREASE 3,377 S.F.
PRELIMINARY SITE PLAN
FORESTER RESIDENCE
4464 ADAMS STREET
MAP
1
OF
CITY OF CARLSBAD, CALIFORNIA L_ _______________________________ ....l..,__ _____ ____.___ ________ ____.
1 ..
d
3i
ADVANCED GEOTECHNICAL SOLUTIONS, INC.
485 Corporate Drive, Suite B
Escondido, California 92029
Telephone: (619) 867-0487 Fax: (714) 786-5661
ORANGE AND L.A. COUNTIES INLAND EMPIRE SAN DIEGO AND IMPERIAL COUNTIES
(714) 786-5661 (619) 867-0487 (619) 867-0487
John Forester December 17, 2021
300 Carlsbad Village Drive, Suite 108a-335 P/W 1901-03
Carlsbad, California 92008 Report No. 1901-03-B-3
Attention: Mr. John Forester
Subject: Geotechnical Addendum and Response to Third-Party Geotechnical Review,
Proposed Single-Family Residence, 4464 Adams Street, Carlsbad, California
References: 1) Advanced Geotechnical Solutions, 2020, Geotechnical Investigation and Preliminary
Design Recommendations for Proposed Single-Family Residence, 4464 Adams Street,
Carlsbad, California, dated December 31, 2019, Report No. 1901-03-B-2.
2) Fusion Eng Tech, 2021, Grading and Improvement Plans for Forester Residence, 4464
Adams Street, plot dated September 1, 2021.
3) Hetherington Engineering, 2021, Third-Party Geotechnical Review Comments (First) 4464
Adams Street, Carlsbad, California, GR2021-0037/CDP2021-0037, their Project No.
9541.1, Log No. 21675, dated November 11, 2021.
Gentlepersons:
In accordance with your request, Advanced Geotechnical Solutions, Inc. (AGS) has prepared this response
to third party geotechnical review comments issued by Hetherington Engineering (2021) on behalf of the
City of San Carlsbad regarding the geotechnical investigation report prepared by AGS (2020) for the
proposed single-family residence project to be located on 4464 Adams Street. The review comments are
presented below followed by our responses. A copy of the review comment sheet is appended.
Comment 1: Due to the age of the geotechnical investigation, the Consultant should update the project
seismic, grading and foundation recommendations to comply with requirements of the 2019 California
Building Code and ASCE 7-16.
AGS Response – As noted in the project geotechnical investigation report by AGS (2020), the site
may be classified as Seismic Site Class D consisting of a stiff soil profile. Site coordinates of
Latitude 33.1456°N and Longitude 117.3272°W were utilized in conjunction with the USGS
Seismic Design Maps web-based ground motion calculator (https://seismicmaps.org/) to obtain the
2019 CBC seismic design parameters presented in Table 1.
~GS
December 17, 2021 Page 2
P/W 1901-03 Report No. 1901-03-B-3
ADVANCED GEOTECHNICAL SOLUTIONS, INC.
TABLE 1 - 2019 CBC SEISMIC DESIGN PARAMETERS
Seismic Site Class D
Mapped Spectral Acceleration Parameter at Period of 0.2-Second, Ss 1.058g
Mapped Spectral Acceleration Parameter at Period 1-Second, S1 0.383g
Site Coefficient, Fa 1.077
Site Coefficient, Fv N/A3
Adjusted MCER1 Spectral Response Acceleration Parameter at Short Period, SMS 1.139g
1-Second Period Adjusted MCER1 Spectral Response Acceleration Parameter, SM1 N/A3
Short Period Design Spectral Response Acceleration Parameter, SDS 0.759g
1-Second Period Design Spectral Response Acceleration Parameter, SD1 N/A3
Peak Ground Acceleration, PGAM2 0.528g
Seismic Design Category N/A3
Notes:1 Risk-Targeted Maximum Considered Earthquake
2 Peak Ground Acceleration adjusted for site effects
3 Requires Site Specific Ground Motion Hazard Analysis per ASCE 7-16 Section 11.4.8 except if CS is determined
by Equation 12.8-2 for values of T 1.5TS and taken as equal to 1.5 times the values computed with either
Equation 12.8-3 for TL ≥ T > 1.5Ts or Equation 12.8-4 for T > TL.
Comment 2: The Consultant should review the project grading and improvement plans (Reference 2), and
foundation plans, provide any additional geotechnical analyses/recommendations considered necessary,
and confirm that the plans have been prepared in accordance with the geotechnical recommendations.
AGS Response - AGS has reviewed the project grading and improvement plans prepared by Fusion
Eng Tech (2021). Based on our review, the project grading and improvement plans have been
prepared in accordance with the recommendations provided by AGS (2020) in the geotechnical
report for the project. Foundation and structural plans have not been provided to AGS for review
but will be reviewed when available.
Comment 3: The Consultant should provide an updated geotechnical map utilizing the current grading
plan for the project to clearly show (at minimum): a) existing site topography, b) proposed
structures/improvements, c) proposed finished grades, d) geologic conditions, e) locations of the subsurface
exploration, f) temporary construction slopes, g) remedial grading, etc.
AGS Response - AGS has prepared the attached Plate 1, Geologic Map and Exploration Location
Plan based on the current rough grading plan by Fusion Eng Tech (2021) which depicts the existing
site topography, proposed structures/improvements, proposed rough grades, geologic conditions
and locations of subsurface exploration by AGS. Recommendations for remedial grading were
provided by AGS (2020) in Section 6.1.2 of the geotechnical report as follows: “Topsoil, artificial
fill, and highly weathered old paralic deposits are considered to be compressible in their current
condition and should be removed in areas to receive fill and where settlement sensitive
improvements are planned...In general, it is anticipated that unsuitable soil removals will be on the
order of 2 to 5 feet deep. Localized areas may require deeper removals. The extent of removals can
best be determined in the field during grading when observation and evaluation can be performed
by the soil engineer and/or engineering geologist.” Recommendations for temporary slopes were
provided by AGS (2020) in Section 6.3 of the geotechnical report.
December 17, 2021 Page 3
P/W 1901-03 Report No. 1901-03-B-3
ADVANCED GEOTECHNICAL SOLUTIONS, INC.
Comment 4: The Consultant should provide geologic cross-sections utilizing the current grading plan to
clearly show (at minimum): a) existing topography, b) proposed structures/improvements, c) proposed
finish grades, d) geologic contacts, e) geologic structure, f) locations of the subsurface exploration, g)
temporary construction slopes, and h) remedial grading, etc.
AGS Response - AGS has prepared the attached geologic cross-section A-A in Plate 1 presenting
the requested information.
Comment 5: The Consultant should address the gross and surficial stability of the proposed slopes.
AGS Response - Fill slopes on the project are designed at 2:1 ratio (H:V). The highest proposed
2:1 fill slope is approximately fourteen (14) feet. Shear strength testing was conducted by AGS
(2021). Revised shear strength parameters used by AGS for slope stability analysis are presented
in Table 2.
TABLE 2
SHEAR STRENGTH PARAMETERS
Material Cohesion
(psf)
Friction Angle
(degrees)
Moist Density
(pcf)
Compacted Fill – afc 200 30 130
Old Paralic Deposits – Qop 200 32 125
Gross stability calculations for 2:1 fill slopes are presented in Figures 1 and 2. Surficial stability
calculations for a 2:1 fill slope are presented in Figure 3. Fill slopes constructed at 2:1 ratios or
flatter can be expected to perform satisfactorily when properly constructed with onsite materials
and maintained. Marginal surficial stability may exist if slopes are not properly maintained or are
subjected to inappropriate irrigation practices. Slope protection and appropriate landscaping will
improve surficial stability and should be considered.
Keyways should be constructed at the toe of all fill slopes toeing on existing or cut grade. Fill keys
should have a minimum width equal to fifteen (15) feet or one-half (1/2) the height of ascending
slope, whichever is greater. Where possible, unsuitable soil removals below the toe of proposed fill
slopes should extend outward from the catch point of the design toe at a minimum 1:1 projection
to an approved cleanout. Backcuts should be cut no steeper than 1:1 (H:V) or as recommended by
the geotechnical engineer.
Where possible, skin fills or thin fill sections against natural slopes should be avoided. If skin fill
conditions are identified in the field or are created by remedial grading, it is recommended that a
backcut and keyway be established such that a minimum fill thickness equal to one-half (1/2) the
remaining slope height [not less than fifteen (15) feet] is provided for all skin fill conditions. This
criterion should be implemented for the entire slope height. Drains are required at the heel of
keyways and will be designed based upon exposed conditions.
December 17, 2021 Page 4
P/W 1901-03 Report No. 1901-03-B-3
ADVANCED GEOTECHNICAL SOLUTIONS, INC.
Comment 6: The Consultant should address impacts to adjacent property and improvements as a result of
site grading and construction.
AGS Response – Based on AGS’ review, site grading and construction will not impact the adjacent
properties or improvements. Permission for offsite grading into Adams Street right-of-way and the
adjacent vacant lot to the east may be necessary to complete the keyway construction on the
southern limits of the project.
Comment 7: The Consultant should provide recommendations for fill keys, benching and subdrainage
(widths, depths, etc.).
AGS Response – Recommendations for fill keyways are provided above in AGS’ response to
Comment 5 and are presented in the attached geologic cross-section A-A.
Comment 8: The Consultant should provide a list of recommended testing and observation during grading
and construction.
AGS Response - Recommendations for testing and observation during grading and construction
remedial grading were provided by AGS (2020) in Section 8.2 - Observation During Construction
of the geotechnical report.
Conditions of the referenced report remain applicable unless specifically superseded herein.
Advanced Geotechnical Solutions, Inc., appreciates the opportunity to provide you with geotechnical
consulting services and professional opinions. If you have any questions, please contact the undersigned
at (619) 867-0487.
Respectfully Submitted,
Advanced Geotechnical Solutions, Inc.
___________________________________ ________________________________
ANDRES BERNAL, Sr. Geotechnical Engineer PAUL J. DERISI, Vice President
RCE 62366/GE 2715, Reg. Exp. 9-30-23 CEG 2536, Reg. Exp. 5-31-23
Distribution: (1) Addressee
Attachments: Plate 1 - Geologic Map and Exploration Location Plan
Figures 1 through 3 - Slope Stability Analyses
Third-Party Geotechnical Review Comments
EI. 82.5'
0-5' Afu
5'-21.5' Qop
No GW
EI. 81.8'
0-2.5' Afu
2.5'-21.5' Qop
T.D.=21.5'
No GW
EI. 94'
0-2.5' Afu
2.5'-21.5' Qop
AAA
Keyway
15x2x3
4
4
4
4
AAA
Tie-In 4" Heel Drain to 8" Storm Drain
Proposed Keyway
Location of Heel Drain
with size in inches4
z:
0
f----<( > LLI _J
LLI
A
100
90
Ir.
80 Adams
Street
70J-.--Y
Existing
Grade
J
206-180-38
Proposed
Wall Retaining Existing
Wall Residence Projected 23'
Proposed \:=:....::==--==j'.:'.t--===--==::....:====::-':::-i;::--:::::. Grode / -, _ -?--
L --/ ?-----
/ ,,-------------=-=-=-=-~==-=-=-=-=--===~i=-=-=-=-=___,,,,,;;::JBT-12 _____ ~-~--?-----.
afu ?--
Qop
a IJ..--
:-=:L----~?"---?-- --?-- - -
---
Qop T.D.=21.5'
Qop
r---PVC ~------/ 4" Drain Pipe
15x2x3
Keyway
60 T.D.=21.5'
CROSS-SECTION A-A'
SCALE: 1"=10'
11,-1
EXISTING l D" ACP WATER ~
MAIN P[R DWG 149-8
Highland A'
Drive
?/ .,,_
100
90
z:
0
f----
80 ;!
70
60
LLI _J
Lu
I
206-192-07
LEGEND:
A
B-3+
afu
Qop
Tsa
A'
Approximate Location of Boring
(AGS, 2017)
Artificial Fill -Undocumented
Old Paralic Deposits
(Bracketed where buried)
Santiago Formation
(Bracketed where buried)
Approximate Location of
Geologic Cross Section
-----?-'
Existing Grade/Structures
Proposed Grade/Structures
Approximate Location of Geologic
Contact (Queried were uncertain)
0--
10
PLATE 1
Geologic Map and Exploration Location Plan
ADVANCED GEOTECHNICAL SOLUTIONS, INC
Project:
P/W 1901-03
Report:
1901-03-B-3
a 10 20
SCALE 1 •-1 O'
FUSION ENG TECH
1810 GILLESPIE WAY #207
EL CAJON, CA 92020
(619) 736-2800
Date:
Dec. 2021
30
rfESS10
x-" s.Riv,: e ,
1'_,. ,ts
C 73878 ~
xp. os/30/23 SI •
CIVIL
C,-c;J>I..I<
"AS BUILT"
RCE EXP. DATE
REVIEWED BY:
INSPECTOR DATE
I SHEET I CITY OF CARLSBAD I SgETS I
ENGINEERING DEPARTMENT
FORESTER RESIDENCE
4464 ADAMS STREET
APPROVED: JASON S. GELDERT
CITY ENGINEER RCE 63912 EXPIRES 9/30/22 DATE
OWN BY:
I
PROJECT NO. I DRAWING NO. CHKD BY:
RVWD BY:
0 20 40 60 80 100
40
60
80
100
1901-03 Forester Residence 2:1 Fill Slope (Static)
k:\1901-03 forester residence\slope stability\highest fill - static.pl2 Run By: AGS 12/17/2021 04:55PM
1
2
3 4
5
6
7
2
1
1 2
2
2
2
bcdefghija
# FS
a 2.469
b 2.469
c 2.469
d 2.472
e 2.472
f 2.485
g 2.485
h 2.487
i 2.487
j 2.487
Soil
Desc.
afc
Qop
Soil
Type
No.
1
2
Total
Unit Wt.
(pcf)
130.0
125.0
Saturated
Unit Wt.
(pcf)
130.0
125.0
Cohesion
Intercept
(psf)
200.0
200.0
Friction
Angle
(deg)
30.0
32.0
Pore
Pressure
Param.
0.00
0.00
Pressure
Constant
(psf)
0.0
0.0
Piez.
Surface
No.
0
0
GSTABL7 v.2 FSmin=2.469
Safety Factors Are Calculated By The Modified Bishop Method
FIGURE 1
•
0 20 40 60 80 100
40
60
80
100
1901-03 Forester Residence 2:1 Fill Slope (Pseudo-static)
k:\1901-03 forester residence\slope stability\highest fill - pseudo static.pl2 Run By: AGS 12/17/2021 04:54PM
1
2
3 4
5
6
7
2
1
1 2
2
2
2
bcdefg hija
# FS
a 1.823
b 1.823
c 1.825
d 1.825
e 1.825
f 1.827
g 1.827
h 1.828
i 1.828
j 1.832
Soil
Desc.
afc
Qop
Soil
Type
No.
1
2
Total
Unit Wt.
(pcf)
130.0
125.0
Saturated
Unit Wt.
(pcf)
130.0
125.0
Cohesion
Intercept
(psf)
200.0
200.0
Friction
Angle
(deg)
30.0
32.0
Pore
Pressure
Param.
0.00
0.00
Pressure
Constant
(psf)
0.0
0.0
Piez.
Surface
No.
0
0
Load Value
Peak(A) 0.528(g)
kh Coef. 0.150(g)<
GSTABL7 v.2 FSmin=1.823
Safety Factors Are Calculated By The Modified Bishop Method
FIGURE 2
•
FORESTER RESIDENCE
SURFICIAL SLOPE STABILITY
Assume: (1) Saturation To Slope Surface
(2) Sufficient Permeability To Establish Water Flow
Pw = Water Pressure Head=(z)(cos^2(a))
Ws = Saturated Soil Unit Weight
Ww = Unit Weight of Water (62.4 lb/cu.ft.)
u = Pore Water Pressure=(Ww)(z)(cos^2(a))
z = Layer Thickness
a = Angle of Slope
phi = Angle of Friction
c = Cohesion
Fd = (0.5)(z)(Ws)(sin(2a))
Fr = (z)(Ws-Ww)(cos^2(a))(tan(phi)) + c
Factor of Safety (FS) = Fr/Fd
2:1 SLOPE - ARTIFICIAL FILL
Given:Ws z a phi c
(pcf)(ft) (degrees)(radians)(degrees)(radians)(psf)
130 4 26.565 0.464 30 0.5236 200
Calculations:
Pw u Fd Fr FS
3.20 199.68 208.00 324.89 1.56
ADVANCED GEOTECHNICAL SOLUTIONS, INC.FIGURE 3
SLOPE SURFACE
--------::--------J a
Fd< l 1 l
Ws-Ww I --------------~ --------------:,-----Fr-----' -------------------
FAILURE PATH
FLOW LINES
HETHERINGTON ENGINEERING, INC.
SOIL & FOUNDATION ENG INEERING • ENGINEERING GEOLOGY • HYDROGEOLOGY
November 11, 2021
Project No. 9 541. l
Log No. 21675
City of Carlsbad
Land Development Engineering
1635 Faraday Avenue
Carlsbad, California 92008-7314
Attentioa:
Subject:
Ms. Nichole Fine
THIRD-PARTY GEOTECHNICAL REVIEW (FIRST)
4464 Adams Street
Carlsbad, California
GR2021-003 7 /CDP202 l-003 7
References: I) "Geotecbnical Investigation and Preliminary Design Recommendations
Dear Ms. Fine:
for Proposed Single-Family Residence, 4464 Adams Street, Carlsbad,
Califomia", by Advanced Geotechnical Solutions, Inc., dated December
31 , 2019.
2) "Grading and Improvement Plans for: Forester Residence, 4464 Adams
Street", by Fusion Eng Tech, undated (9-sheets).
In accordance with your request, Hetherington Engineeiing, Tnc. has provided third-party
geotechnical review of Reference l. The following comments are provided for analyses
and/or response by the Geotechnkal Consultant.
I . Due to the age of the geotechnical investigation, the Consultant should update the
project seismic, grading and foundation recommendations to comply with requirements
of the 2019 Califonnia Building Code and ASCE 7-16.
2. The Consultant should review the project grading and improvement plans (Reference
2), and foundation plans, provide any additional geotechnical
analyses/recommerndations considered necessary, and confirm that the plans have been
prepared in accordance with the geotechnical recommendations.
3. The Consultant should provide an updated geotechnical map utilizi1ig the current
grading plan for the project to clearly show (at minimum): a) existing site topography,
b) proposed structures/improvements, c) proposed finished grades, d) geologic
conditions, e) locations of the subsurface exploration, t) temporary construction slopes,
g) remedial grading, etc.
5365 Avenida Encinas, Suite A • Carlsbad, CA 92008-4369 • (760) 931 -1917 • Fax (760) 931-0545
333 Third Street •· Laguna Beach, CA 92651 • (949) 715-5440 • Fax (949) 715-5442
www.hetheringtonengineering.com
THIRD-PARTY GEOTECHNICAL REVIEW (FIRST)
Project No 9541. l
Log No. 21675
November 11, 2021
Page 2
4. The Consultant should provide geologic cross-sections utilizing the current grading
plan to clearly show (at minimum): a) existing topography, b) proposed
sh1.1ctures/improvements, c) proposed finish grades, d) geologic contacts, e) geologic
structure, f) locations of the subsurface exploration, g) tempora1y construction slopes,
and h) remedial grading, etc.
5. The Consultant should address the gross and surficial stability of tbe proposed slopes.
6. The Consultant should address impacts to adjacent property and improvements as a
result of site grading and construction.
7. The Consultant should provide recommendations for fill keys, benching and
subdrainage (widths, depths, etc).
8. The Consultant should provide a list of recommended testing and observation during
grading and construction.
'
Please call if there are any questions.
Sincerely,
HETHERING
Paul A. Bogs
Professi01 Geol gist
Certified ngineering Geologist 1153
Certified Hydrogeologiist 591
(expires 3/31/22)
etherington
Civil Engineer 30488
Geotechnical Engineer 397
(expires 3/31/22)
Distribution: 1-via e-mail (Nicho1e.Finc@carlsbadca.gov)
1-via e-mail (1detrackingdesk@carlsbadca.gov)
1-via e-mail (Tim.Carroll@carlsbadca.gov)
HETHERINGTON ENGINEERING, INC.