HomeMy WebLinkAboutCT 2018-0003; MAGNOLIA BRADY; STORM WATER QUALITY MANAGEMENT PLAN; 2019-10-11CITY OF CARLSBAD
PRIORITY DEVELOPMENT PROJECT (PDP)
FINAL STORM WATER QUALITY MANAGEMENT PLAN (SWQMP)
FOR
Magnolia-Brady
PROJECT ID: GR2018-0047 / GR2019-0021
DWG 515-3A / 515-3B
ENGINEER OF WORK:
PREPARED FOR:
Magnolia A3, LLC
5 Hoya Street
Rancho Mission Viejo, CA 92694
(914) 584-2041
PREPARED BY:
Civil andworks
Civil Landworks Corporation
110 Copperwood Way Suite P,
Oceanside CA, USA 92058
760-908-87 45
DATE:
October 11 , 2019
lo -11-1
Date
RECEIVED
OCT i 5 2019
LAND DEVELOPMENT
ENGINEERING
Project Name: Magnolia-Brady
Project ID: CT2018-0003
CERTIFICATION PAGE
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 .
ark's Signature, RCE No . 70066, Exp 9-30-20
David Caron
Print Name
Civil Landworks Corp.
Company
Date
PROJECT VICINITY MAP
/'\ \ ~\ I
S ITE VIC I N ITY MAP
MAGNOLIA AVE
City's Storm Water Standard Questionnaire (Form E-34)
( Cilyof
Carlsbad
STORM WATER STANDARDS
QUESTIONNAIRE
Development Services
Land Development Engineering
1635 Fa ra day Avenue
(760) 602-2750
www.carlsbadca.gov
E-34
I 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 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: Magnolia-Brady PROJECT ID: CT2018-0003
ADDRESS: Brady Circle APN : 205-220-15 and 205-220-16
The project is (check one): D New Development ~ Redevelopment
The total proposed disturbed area is: 81 ,842 ft2 ( 1.879 ) acres
The total proposed newly created and/or replaced impervious area is: 30,100 ft2 ( 0.691 ) 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.
E-34 Page 1 of 4 REV 02/16
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 □ li1 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 5, mark the third 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; □ li1 b) Designed and constructed to be hydraulically disconnected from paved streets or roads;
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 □ li1 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? □ li1
If you answered "yes" to one or more of the above questions, provide discussion/justification below, then go to Step 5, mark
the second box stating "my project is EXEMPT from PDP ... " and complete applicant information.
Discussion to justify exemption ( e.g. the project redeveloping existing road designed and 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.
E-34 Page 2 of 4 REV02/16
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, □ Ill
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 Ill □ 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 facil ity that sells prepared foods and drinks for consumption, including stationary lunch counters and □ Ill
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 □ Ill
development project includes development on any natural slope that is twenty-five percent or Qreater.
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 park ing lot? A parking lot is □ Ill 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 surface collectively over the entire project site and supports a street, road , highway □ Ill freeway or driveway? A street, road, highway, freeway or driveway is any paved impervious surface
used for the transportation of automobiles, trucks, motorcycles, and other vehicles.
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 □ Ill
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 you r proj ect 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 □ Ill 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 □ Ill 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 you r project a new or redevelopment project that results in the disturbance of one or more acres of land IZI □ and are expected to generate pollutants post construction?
11 . Is you r 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 □ Ill
21.203.040)
If you answered "yes" to one or more of the above questions, your project is a PDP. If your project is a redevelopment
project, go to step 4. If your project is a new project, go to step 5, check the first box stating "My project is a PDP ... ,,
and complete applicant information.
If you answered "no" to all of the above questions, your project is a 'STANDARD PROJECT.' Go to step 5, check the
second box statinQ "My project is a 'STANDARD PROJECT' ... " and complete applicant information.
E-34 Page3of4 REV 02/16
STEP 4
i TO BE COMPLETED FOR REDEVELOPMENT PROJECTS THAT ARE PRIORITY DEVELOPMENT PROJECTS (PDP)
ONLY I C,..11"µiete the qJeS'.')rl':' tA:dow '01:Ji:1fd1·irJ )'OLlf •eJevelO[.l'' lj'lt OfOJ8'.'.1 (MS4 Pcnrnt Prr./v,SIC'I t ,:,.l;·(2),
r YfS
. DC<c'S the reaeveloprnont f.:,OJeCt 1esclt If' the creat,O·1 or replacerr<Jrl of 1mperv,ou::; SL,ffclCC fl an i::1111CJfl,
of less t11an 50% 0f thEc swfact°: area o' the rrev;ot.sly Ax•st1ng ClP.velonmeni? C:omr,IR'e i.-,., percent
1rnpe•v1ovs c.ak:ulat1or· DCJlow
Ex st ng 1mr,erv:O1.,s area (,/J,; cc --------• sq -'t
To:al Droposed ncw:y vealec ~lf repli::l(..er.1 ,rnperv,oL,s area (Bl= _,_l _,_1 __________ sq 1l
. .. 6 't Percent 111merv1ous acea created or replaced t81A1 ·oo . _ % ------------------------·
NO
1· you answered 'yes the structural BMPs reqJtred for PDP apply only to the crea•ion or replacen°ert of impervious
s,1rfacE: ar· d nc,t t:1e entire rlevAlopme0t Go to step 5, checi< the firs1 on:< stating My proJect is a PDP ·· ano r.ornple·e
apolicant nfo,mat1on
If you answe1ed no 'the str1.,ctural BMP s requ,red for PDP appiy •o tt·,e entire oeveluprnent Go to step 5 c11eck the
:hecv~ th~ first bg_x 3tat1n_g 'My_projec_::t s a PDP ' ar:id corrplete appl1car~_ 1nforma1!on
STEP5 _J
CHECK THE APPROPRIATE BOX AND COMPLETE APPLICANT INFORMATION
iZ] My p, OJect is a PDP and must comply with PDP sturrnwater requ1rerPer1ts ot tt10 BMP Mam,a, I wderstand I mu:;,t
prepared Storm Water Cluality r,.1c.rnagernen: Pia,·, (SWQMP) •or subm t'.al at t'lle of apol1cation
::J My p10JPr.t is a ·STANDARD PROJECT' OR EXEMPT 1rom PDP ano must only comply w1m STANDARD PROJECT'
~lorrnwater re3,u"er:·enl_s of the ,BMP Mi:lr'Ual As par: of these requirements, I Will submit a "Sta11(ll:lld Pl()_tf'l:t I
1-'or,'u,1t.11Y11t (. nC'ci,1,st r . .rm E 36 ancl 111<: ,)rpcra0e low ,l'·1pact dp,;elopment strategies tnrough0ut n,y oroJect
Note F 01 prcJects that are close to rnect.ng cr'e PDP triresttolc, s.aff rr 3/ reqc;trE: de,d1led 1rLpervi<.:ius area calcl.lat1ons
c,rvi exh1b1ts to venfv· tf STANDARD PROJFCT' storn-iwater reotwer· a.,ts applv
n My ProJed ,5 NOT a 'development project and IS not SUbjCG'. to the requremerrs 01 the ur-,,;p Manual.
Appl:cw,t lnfrJrnaMn anrl S1gnatcr1:: Box
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SITE INFORMATION CHECKLIST
Proiect Summarv Information
Project Name Magnolia-Brady
Project ID CT2018-0003
Project Address Brady Circle
Carlsbad, California 92008
Assessor's Parcel Number(s) (APN(s)) 205-220-15 and 205-220-16
Project Watershed (Hydrologic Unit) Carlsbad 904 -Encinas 904.4
Parcel Area
1.740 Acres ( 75 786 Sauare Feet)
Existing Impervious Area
(subset of Parcel Area) 0.115 Acres ( 5,031 Square Feet)
Area to be disturbed by the project
(Project Area) 1.915 Acres ( 83,417 Square Feet)
Project Proposed Impervious Area
(subset of Project Area) 0.691 Acres ( 30,100 Square Feet)
Project Proposed Pervious Area
(subset of Project Area) 1.076 Acres ( 45,686 Square Feet)
Note: Proposed Impervious Area + Proposed Pervious Area = Area to be Disturbed by the
Project.
This mav be less than the Parcel Area.
Description of Existing Site Condition and Drainage Patterns
Current Status of the Site (select all that apply):
l:8l Existing development
□ Previously graded but not built out
□ Agricultural or other non-impervious use
o Vacant, undeveloped/natural
Description/ Additional Information:
Existing area consist of a single-family residence.
Existing Land Cover Includes (select all that apply):
l:8l Vegetative Cover
l:8l Non-Vegetated Pervious Areas
l:8l Impervious Areas
Description/ Additional Information:
Existing site's pervious area is covered with dirt, cobble, and grasses.
Impervious area consists of building footprint and AC driveway.
Underlying Soil belongs to Hydrologic Soil Group (select all that apply):
D NRCS Type A
l:8l NRCS Type B
D NRCS Type C
l:8l NRCS Type D
Approximate Depth to Groundwater (GW):
D GW Depth < 5 feet
□ 5 feet < GW Depth < 10 feet
□ 10 feet< GW Depth< 20 feet
l:8l GW Depth> 20 feet
Existing Natural Hydrologic Features (select all that apply):
□ Watercourses
□ Seeps
□ Springs
□Wetlands
l:8l 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 existing site consists of a single-family residence with a partial paved AC driveway. The
eastern portion of the site slopes westerly, and the northern portion of the site slopes southerly.
All drainage onsite converges into an existing basin inlet at the middle of the site along the
westerly property line. The basin inlet connects to an existing storm system on Brady Circle.
There appears to be grading for the depression around the basin inlet. There is little offsite
run on from the slopes belonging to the adjacent school property to the east of the site.
Ultimately, all the stormwater onsite and runons from offsite are either captured via the basin
inlets onsite then discharge to existing storm system on Brady Circle. The existing storm
system empties into Agua Hedionda Lagoon which outlets to the Pacific Ocean.
Description of Proposed Site Development and Drainage Patterns
Project Description / Proposed Land Use and/or Activities:
The proposed project will include subdividing the parcel into eight lots to construct seven single-
family residences and one lot for storm water treatment and detention.
List/describe proposed impervious features of the project (e.g., buildings, roadways, parking
lots, courtyards, athletic courts, other impervious features):
The proposed impervious areas include building footprints and hardscape.
List/describe proposed pervious features of the project (e .g., landscape areas):
The proposed pervious areas include landscape areas, pervious pavement and a biofiltration
basins.
Does the project include grading and changes to site topography?
IZI Yes
D No
Description / Additional Information:
The project will change the existing slopes to create flat pads for the seven lots to incorporate
the new buildings. However, the proposed site will minimize grading to the maximum extent
possible to maintain similar topography and drainage as the existing condition.
Does the project include changes to site drainage (e.g., installation of new storm water
conveyance systems)?
IZI Yes
□No
Description / Additional Information:
The proposed development will maintain the same drainage pattern as the existing to the
maximum extent possible. Drainage from all eight new lots will consolidate into one, where it
will be treated and detained, then discharge into the existing storm system on Brady Circle. The
front yard will be compose of landscaping and pervious pavement. The landscape, in the front
of the residential lots and the pervious pavement will be considered self-retaining areas.
Installation of brow ditches along the easterly property line will collect all offsite runons to
prevent co-mingling with the onsite storm water. The offsite runons will be conveyed through
the site via a proposed storm drain system and discharge to the existing storm system on Brady
Circle.
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
D Pools, spas, ponds, decorative fountains, and other water features
D Food service
D 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
D Miscellaneous Drain or Wash Water
D 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):
The storm water from the site and offsite runons will be captured via onsite basin inlet, then
discharge to the existing public storm system on Brady Circle. The public storm system will
discharge the storm water into Agua Hedionda Lagoon which outlet to the Pacific Ocean.
List any 303(d) impaired water bodies within the path of storm water from the project site to the
Pacific Ocean (or bay, lagoon, lake or reservoir, as applicable), identify the
pollutant(s)/stressor(s) causing impairment, and identify any TMDLs for the impaired water
bodies:
303(d) Impaired Water Body Pollutant(s)/Stressor(s) TMDLs
Agua Hedionda Lagoon No Listings No Listings
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):
Also a Receiving
Not Applicable to Anticipated from the Water Pollutant of
Pollutant the Project Site Project Site Concern
Sediment X
Nutrients X
Heavy Metals X X
OrQanic Compounds X
Trash & Debris X
Oxygen Demanding
Substances X
Oil & Grease X
Bacteria & Viruses X
Pesticides X 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 reseNoirs, lakes, enclosed embayments, or the Pacific Ocean.
D No, the project will discharge runoff directly to conveyance channels whose bed and bank are
concrete-lined all the way from the point of discharge to water storage reservoirs, lakes,
enclosed embayments, or the Pacific Ocean.
□ 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 project discharges into an existing storm drain system that outlets into Agua Hedionda
Lagoon then the Pacific Ocean. The existing storm drain system is shown as an exempt
system. See Attachment 2a for mapping of exempt areas.
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?
D 6.2.1 Verification of Geomorphic Landscape Units (GLUs) Onsite
D 6.2.2 Downstream Systems Sensitivity to Coarse Sediment
D 6.2.3 Optional Additional Analysis of Potential Critical Coarse Sediment Yield Areas Onsite
D 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?
D No critical coarse sediment yield areas to be protected based on verification of GLUs onsite
D Critical coarse sediment yield areas exist but additional analysis has determined that
protection is not required. Documentation attached in Attachment 8 of the SWQMP.
D 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:
Flow Control for Post-Project Runoff"
*This Section only reauired if hvdromodification management reauirements 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.
The proposed project has one point of compliance located at the existing storm system on
Brady Circle. All onsite storm water, after treatment and detention, and offsite runons will be
directed toward this location.
Has a geomorphic assessment been performed for the receiving channel(s)?
~ No , the low flow threshold is 0.1 Q2 (default low flow threshold)
□ Yes, the result is the low flow threshold is 0.1 Q2
□ 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)
Other Site Requirements and Constraints
When applicable, list other site requirements or constraints that will influence storm water
management design, such as zoning requirements including setbacks and open space, or City
codes governing minimum street width, sidewalk construction, allowable pavement types, and
drainage requirements.
NIA
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.
NIA
(_ City of
Carlsbad
Project Name: Magnolia-Brady
Project ID: CT2018-0003
STANDARD PROJECT
REQUIREMENT
CHECKLIST
E-36
Project Information
DWG No. or Building Permit No.: DWG 515-3A
Source Control BMPs
Development Services
Land Development Engineering
1635 Faraday Avenu e
(760) 602-2750
www.carl sbadca.gov
All development projects must implement source control BMPs SC-1 through SC-6 where applicable and feasible. See
Chapter 4 and Appendix E.1 of the BMP Design Manual for information to implement source control BMPs shown in this
checklist.
Answer each category below pursuant to the following.
• "Yes" means the project will implement the source control BMP as described in Chapter 4 and/or Appendix E.1 of the
Model BMP Design Manual. Discussion/justification is not required.
• "No" means the BMP is applicable to the project but it is not feasible to implement. Discussion/justification must be
provided. Please add attachments if more space is needed.
• "N/A" means the BMP is not applicable at the project site because the project does not include the feature that is
addressed by the BMP (e .g., the project has no outdoor materials storage areas). Discussion/justification may be
provided.
Source Control Requirement Applied?
SC-1 Prevention of Ill icit Discharges into the MS4 ~ Yes O No ON/A
Discussion/justification if SC-1 not implemented:
SC-2 Storm Drain Stenciling or Signage ~ Yes □ No □ N/A
Discussion/justification if SC-2 not implemented:
SC-3 Protect Outdoor Materials Storage Areas from Rainfall , Run-On, Runoff, and Wind □ Yes □ No ~ N/A Dispersal
Discussion/justification if SC-3 not implemented:
No outdoor materials storage areas on proposed project.
E-36 Page 1 of 4 Revised 03/16
Source Control Requirement (continued) Applied?
SC-4 Protect Materials Stored in Outdoor Work Areas from Rainfall, Run-On, Runoff, and □ Yes □ No [Z] N/A Wind Dispersal
Discussion/justification if SC-4 not implemented:
No materials stored in outdoor work areas on project.
SC-5 Protect Trash Storage Areas from Rainfall, Run-On, Runoff, and Wind Dispersal □ Yes □ No [Z] N/A
Discussion/justification if SC-5 not implemented:
No outdoor trash storage areas on project.
SC-6 Additional BMPs based on Potential Sources of Runoff Pollutants must answer for each source listed below and
identify additional BMPs. (See Table in Appendix E.1 of BMP Manual for guidance).
[Z] On-site storm drain inlets [Z] Yes □ No □ N/A
□ Interior floor drains and elevator shaft sump pumps □ Yes □ No [Z] N/A
[Z] Interior parking garages [Z] Yes □ No □ N/A
□ Need for future indoor & structural pest control □ Yes □ No [Z] N/A
[Z] Landscape/Outdoor Pesticide Use [Z] Yes □ No □ N/A
□ Pools, spas, ponds, decorative fountains, and other water features □ Yes □ No [Z] N/A
□ Food service □Yes □ No [Z] N/A
□ Refuse areas □Yes □ No [Z] N/A
□ Industrial processes □ Yes □ No [Z] N/A
□ Outdoor storage of equipment or materials □ Yes □ No [Z] N/A
□ Vehicle and Equipment Cleaning □ Yes □ No [Z] N/A
□ Vehicle/Equipment Repair and Maintenance □ Yes □ No [Z] N/A
□ Fuel Dispensing Areas □ Yes □ No [Z] N/A
□ Loading Docks □ Yes □ No [Z] N/A
□ Fire Sprinkler Test Water □ Yes □ No [Z] N/A
□ Miscellaneous Drain or Wash Water □ Yes □ No [Z] N/A
□ Plazas, sidewalks, and parkinq lots □ Yes □No [Z] N/A
For "Yes" answers, identify the additional BMP per Appendix E.1. Provide justification for "No" answers.
On-ste storm drain in lets:
Mark all inlets with the words "No Dumping! Flows to Bay" or simi lar.
Interior parking garages:
All interior floor drains will be plumbed to sanitary sewer.
Landscape/Outdoor Pesticide Use:
Use low irrigated or drought tolerant plants.
E-36 Page 2 of4 Revised 03/16
Site Design BMPs
All development projects must implement site design BMPs SD-1 through SD-8 where applicable and feasible. See
Chapter 4 and Appendix E.2 thru E.6 of the BMP Design Manual for information to implement site design BMPs shown in
this checklist.
Answer each category below pursuant to the following.
• "Yes" means the project will implement the site design BMPs as described in Chapter 4 and/or Appendix E.2 thru E.6 of
the Model BMP Design Manual. Discussion/ justification is not required .
• "No" means the BMPs is applicable to the project but it is not feasible to implement. Discussion/justification must be
provided. Please add attachments if more space is needed.
• "N/A" means the BMPs is not applicable at the project site because the project does not include the feature that is
addressed by the BMPs (e .g., the project site has no existing natural areas to conserve). Discussion/justification may be
provided.
Source Control Requirement I Applied?
SD-1 Maintain Natural Drainaqe Pathwavs and Hydrologic Features I (;z] Yes I D No I D N/A
Discussion/justification if SD-1 not implemented:
SD-2 Conserve Natural Areas, Soils, and Vegetation I (;z]Yes I D No I D N/A
Discussion/justification if SD-2 not implemented:
SD-3 Minimize Impervious Area I (;z] Yes I D No I D N/A
Discussion/justification if SD-3 not implemented:
SD-4 Minimize Soil Compaction I (;z] Yes I D No I D N/A
Discussion/justification if SD-4 not implemented:
SD-5 Impervious Area Dispersion I (;z] Yes I D No I D N/A
Discussion/justification if SD-5 not implemented:
E-36 Page 3 of 4 Revised 03/16
Source Control Requirement (continued) I Applied?
SD-6 Runoff Collection I '21 Yes I D No ID N/A
Discussion/justification if SD-6 not implemented:
SD-7 Landscaping with Native or Drought Tolerant Species I '21 Yes I D No ID N/A
Discussion/justification if SD-7 not implemented:
SD-8 Harvestin!=) and Usin!=l Precipitation I D Yes I '21 No ID N/A
Discussion/justification if SD-8 not implemented:
Harvest and use is considered to be infeasible.
See Appendix 1 c for additional info.
E-36 Page 4 of4 Revised 03/16
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 co nstruction 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.
Harvest and use BMPs demand calculation are as follows:
The estimate anticipated average wet season demand over a period of 36 hours.
3 (residents per home) x 7 (homes) x 9.3 (flushes per resident) = 195.3 gal or 26.1 cf.
2.8 (avg. evapotranspiration) x [(0.2 plant factor x 44 ,740 SF landscape area)/ 90% irrigation
efficiency] x 0.015 = 417 cf
DCV per Worksheet B.2-1 = 1,660 cf.
Is the 36-hour demand greater than or equal to the DCV? NO
Is the 36-hour demand greater than 0.25DCV but less than the full DCV? NO
Is the 36-hour demand less than 0.25DCV? YES
Harvest and use is considered to be infeasible.
The following are factors when considering retention or infiltration. According to the USGS web
survey, the proposed development resides on soil Type "B" and Type "D". Type "B" soil have
moderate infiltration rates when thoroughly wet, while Type "D" soil have poor infiltration rates
when thoroughly wet. The majority of the site sits on Type "D" soil. Per the Geotechnical
Investigation performed by Geocon Inc. dated January 17, 2018, infiltration rates of 0.07 and
0.32 inches/hour were found on site, averaging to 0.20 inches/hour. Using a factor safety of 2,
a recommended average infiltration rate of 0.10 infiltration rate can be used for the site. Due to
the low infiltration rates , infiltration BMP are deemed infeasible for the proposed development.
Per Table D.5-1 City of Carlsbad BMPDM , a factor of safety was calculated to be 2.19. The
site, which resulted in an infiltration rate of 0.09 inches/hour. Due to such low infiltration rates,
full infiltration basin is deemed infeasible.
Biofiltration basin was chosen for this project. Since there is some appreciable rate of
infiltration , the bottom of the biofiltration basins will be unlined. All site drainage will surface flow
toward the biofiltration basins. The biofiltration basins will be equipped with a flow control
structure that will allow for infiltration, treatment and detention during smaller storm event, while
allowing larger storm events to bypass and discharge into the existing storm water system on
Brady Circle.
Permeable pavement for OMA -2A, 3A, 4A, SA , 6A, and 7 A are considered self-retaining
permeable pavement per SW Section 5.2.3 and SD-6B. Therefore no DCV will be treated.
Structural BMP Summary Information
[Copy this page as needed to provide information for each individual proposed
structural BMP]
Structural BMP ID No. BMP-1
DWG 515-3A Sheet No. 2
Type of structural BMP:
D Retention by harvest and use (HU-1)
D Retention by infiltration basin (I NF-1)
□ Retention by bioretention (INF-2)
D Retention by permeable pavement (INF-3)
~ Partial retention by biofiltration with partial retention (PR-1)
D 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
□ Other (describe in discussion section below)
Purpose:
~ Pollutant control only
D Hydromodification control only
□ Combined pollutant control and hydromodification control
D Pre-treatment/forebay for another structural BMP
D Other (describe in discussion section below)
Discussion (as needed):
Per BMP spreadsheet, the drawdown time of the surface has been met to comply with the DEH
drawdown guidelines for vector control.
Structural BMP Summary Information
[Copy this page as needed to provide information for each individual proposed
structural BMP]
Structural BMP ID No. BMP-2
DWG 515-3A Sheet No. _4'--'-5=----
Type of structural BMP:
□ Retention by harvest and use (HU-1)
□ Retention by infiltration basin (I NF-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
IZI Other (describe in discussion section below)
Purpose:
IZI Pollutant 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):
Pervious pavers for dri veways and walkways will be constructed for this project. Pervious
pavers will be for pollutant control only.
Attachment 1
BACKUP FOR PDP POLLUTANT CONTROL BMPS
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 Contents Checklist
Sequence
Attachment 1 a DMA Exhibit (Required) 1:81 Included
See DMA Exhibit Checklist on the
back of this Attachment cover sheet.
(24"x36" Exhibit typically required)
Attachment 1 b Tabular Summary of DMAs Showing 1:81 Included on DMA Exhibit in
DMA ID matching DMA Exhibit, DMA Attachment 1a
Attachment 1 c
Area, and DMA Type (Required)* □ Included as Attachment 1 b,
*Provide table in this Attachment OR
on DMA Exhibit in Attachment 1 a
Form 1-7, 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 1-7.
separate from DMA Exhibit
1:81 Included
□ Not included because the entire
project will use infiltration BMPs
Attachment 1d Form 1-8, Categorization of Infiltration 1:81 Included
Feasibility Condition (Required unless □ Not included because the entire
the project will use harvest and use project will use harvest and use
BMPaj BMPs
Refer to Appendices C and D of the
BMP Design Manual to complete
Form 1-8.
Attachment 1 e Pollutant Control BMP Design 1:81 Included
Worksheets/ Calculations (Required)
Refer to Appendices B and E of the
BMP Design Manual for structural
pollutant control BMP design
guidelines
Use this checklist to ensure the required information has been included on the OMA
Exhibit:
The OMA 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 (OMA) boundaries, OMA ID numbers, and OMA areas (square
footage or acreage), and OMA type (i.e., drains to BMP, self-retaining , or self-mitigating)
□ Structural BMPs (identify location and type of BMP)
Attachment la
OMA Exhibit
0, ---
·-j
DMA-1A L/
'
==========--s-o-~-s~~~---
3 1/8" MIN. THICKNESS
PAVERS W/ MIN. 3/8" VOID
BEDDING COURSE -1.5"
THICK OF 1 /8" TO 3/8"
(N0.8) AGGREGATE
6" CLASS 2 AGGREGATE
PIPE AT 1"
ABOVE SUBGRADE
/
•
VOID FILLER -1/8" TO 3/8" (NO. 8)
AGGREGATE IN VOIDS
4.5"
•
4
CONCRITT FOOTING
MIN. 12" IN SUBGRADE
.,_-'-'•~ 0~5'
3" PERFORATED PIPE
SCH 40, PVC
SOIL SUBGRADE
PERMEABLE PAVERS DETAIL OR EQUIVALENT
/ 6" MIN. FREEBOARD
I 148.80FG
N.T.S.
IMPERMEABLE LINER*
MIRAFI 140N OR EQUIV.
1:1 EXCAVATED
SLOPE
MIN. 18" MEDIA **~TH
MIN. 5 IN/HR
FILlRATION RATE
3" OF 3/8" GRAVEL
UNDER PERFORATED
PIPE
24"X24" OVERFLOW
RISER
12" WATER SURFACE
EXISTING
UNCOMPACTED SOILS
",· L====rt-1---fl
6" MIN. FREEBOARD 7 RIPRAP PER PLAN
148.30TG
149.00FG \ ~~~~~~Z!::,(_
L TERRA TEXN0.3 FILTER
BLANKET
3
ORIFICE PLATE
( 4.6" ORIFICE)
SEE DETAIL RIGHT
T = 2 BLANKETS
IMPERMEABLE LINER*
MIRAFI 140N OR EQUIV.
10" TOTAL OF 3/8" GRAVEL
PERVIOUS MICROFILTIER FABRIC AROUND
GRAVEL MIRAFI 140N "FILlRATION" OR
EQUIVALENT
12" SO OUTILET
144.971E
Civil Dandworks *IMPERMEABLE LINER TO BE PLACED ALONG THE SIDES OF THE BIORETENTION BASIN
110 COPPERWOOD WAY, SUITE P, OCEANSIDE, CA 92058
PH: 760-908-8745 • info@civillandworks.com
**BIORETENTION 'ENGINEERED SOIL?LAYER SHALL BE MINIMUM 18?DEEP 'iSANDY LOAM?SOIL MIX ~TH NO MORE THAN 5% CLAY
CONTENT. THE MIX SHALL CONTAIN 50-60% SAND, 20-30% COMPOST OR HARDWOOD MULCH, AND 20-30% TOPSOIL
DETAIL 1: BIOFILTRATION WITH
PARTIAL RETENTION BASIN
NTS
LOT SUMMARY
LOT 1 -DRAINS TO BILFILTRATION BASIN
SURFACE TYPE AREA (SF)
ROOF /PAVEMENT 4,300
LANDSCAPE-B 0
LANDSCAPE-0 4,065
PERVIOUS PAYERS 225
LOT 2 -DRAINS TO BILFILTRATION BASIN
SURFACE TYPE AREA (SF)
ROOF/PAVEMENT 4,300
LANDSCAPE-B 0
LANDSCAPE-D 4,249
PERVIOUS PAYERS ~ 103
LOT 3 -DRAINS TO BILFILTRATION BASIN
SURFACE TYPE AREA (SF)
ROOF /PAVEMENT 4,300
LANDSCAPE-B 0
LANDSCAPE-0 4,097
PERVIOUS PA VERS 118
LOT 4 DRAINS TO BIOFIL TRA TION BASIN
SURFACE TYPE AREA (SF)
ROOF/PAVEMENT 4,300
LANDSCAPE-B 0
LANDSCAPE-0 2,892
PERVIOUS PAYERS 105
LOT 5 -DRAINS TO BIOFIL TRA TION BASIN
SURFACE TYPE AREA (SF)
ROOF /PAVEMENT 4,300
LANDSCAPE-B 0
LANDSCAPE-D 2,710
wr.:,,===➔
/
LOT 1 -SELF MITIGATING / SELF RETAINING LOT 6 -DRAINS TO BIOFIL TRA TION BASIN
SURFACE TYPE AREA (SF) SURFACE TYPE AREA (SF)
PERVIOUS PAVEMENT -SELF RETAINING 855 ROOF /PAVEMENT 4,300
LANDSCAPE -SELF MITIGATING 1,297 LANDSCAPE-B 1,086
LANDSCAPE-0 1,807
PERVIOUS PAYERS 104
LOT 2 -SELF MITIGATING / SELF RETAINING LOT 7 -DRAINS TO BILFILTRATION BASIN
SURFACE TYPE AREA (SF) SURFACE TYPE AREA (SF)
PERVIOUS PAVEMENT -SELF RETAINING 655 ROOF /PAVEMENT 4,300
LANDSCAPE -SELF MITIGATING 1,501 LANDSCAPE-B 2,436
LANDSCAPE-0 1,096
PERVIOUS PA VERS 173
LOT 3 -SELF MITIGATING / SELF RETAINING LOT 8 -DRAINS TO BILFILTRATION BASIN
SURFACE TYPE AREA (SF) SURFACE TYPE AREA (SF)
PERVIOUS PAVEMENT -SELF RETAINING 790 ROOF/PAVEMENT 0
LANDSCAPE -SELF MITIGATING 1,365 LANDSCAPE-B 4,522
LANDSCAPE-D 2,518
LOT 4 -SELF MITIGATING / SELF RETAINING
SURFACE TYPE AREA (SF)
PERVIOUS PAVEMENT -SELF RETAINING 558
LANDSCAPE -SELF MITIGATING 1,227
LOT 5 -SELF MITIGATING / SELF RETAINING
SURFACE TYPE AREA (SF)
PERVIOUS PAVEMENT -SELF RETAINING 495
LANDSCAPE -SELF MITIGATING 1,290
♦
<
LOT 6 -SELF MITIGATING / SELF RETAINING
SURFACE TYPE AREA (SF)
PERVIOUS PAVEMENT -SELF RETAINING 558
LANDSCAPE -SELF MITIGATING 1,227
LOT 7 -SELF MITIGATING / SELF RETAINING
SURFACE TYPE
PERVIOUS PAVEMENT -SELF RETAINING
LANDSCAPE -SELF MITIGATING
20 0 20
GRAPHIC SCALE
SCALE: 1"= 20'
AREA (SF)
693
1,720
40
ATTACHMENT 1A
OMA EXHIBIT
LANDSCAPE
LEGEND
llEM
SUBDIVISION BOUNDARY
OMA-AREA
HYDROLOGIC SOIL GROUP LINE
HARDSCAPE/ROOF
DMA BOUNDARY
BIOFIL lRA TION BASIN
PERVIOUS PA'IEMENT
FLOW DIRECTION
NOlE:
SYMBOL
DIIA-X
r .... ·J . . . . .
--)
1. GROUNDWATER WAS NOT ENCOUNTER WITHIN 12 FEET OF BORING
EXPLORATION PER PRELIMINARY GEOTECHNICAL EVALUATION BY GEOCON
INC.
2. SITE SOIL TYPE INCLUDES TYPE "B" AND TYPE "D"
3. SEE OMA SUMMARY IN ATTACHMENT 1B
DMASUMMARY
DMA ID Type
DMA-1A Roof/Pa\e!llent
DMA-1 B Landscape-B
DMA-1 C Landscape-D
DMA-1 D PeNious pawnent
TOTAL
DMA ID Type
DMA-2A PeNious Pa\e!llent -Self Retaining
DMA-2B Landscape-Self Mitigating
TOTAL
DMA ID Type
DMA-3A PeNious Pa\ement -Self Retaining
DMA-3B Landscape-Self Mitigating
TOTAL
DMA ID Type
DMA-4A PeNious Pa\ement -Self Retaining
DMA-4B Landscape-Self Mitigating
TOTAL
DMA ID Type
DMA-SA PeNious Pa\e!llenl -Self Retaining
DMA-5B Landscape-Self Mitigating
TOTAL
DMAID
DMA-6A
DMA-6B
TOTAL
Type
PeNious Pa\e!llent -Self Retaining
Landscape-Self Mitigating
DMA ID Type
DMA-7 A PeNious Pa\e!llenl -Self Retaining
DMA-7B Landscape-Self Mitigating
TOTAL
DMA ID Type
DMA-BA PeNious Pa\e!llent -Self Retaining
DMA-8B Landscape-Self Mitigating
TOTAL
Total Area
SF
30,100
8,044
22,491
943
61,578
Total Area
SF
855
1,297
2,152
Total Area
SF
655
1,501
2,156
Total Area
SF
790
1,365
2,155
Total Area
SF
558
1,227
1,785
Total Area
SF
495
1,290
1,785
Total Area
SF
558
1,227
1,785
Total Area
SF
693
1,720
2,413
Total Area
Acres
0.691
0.185
0.516
0.022
1.414
Total Area
Acres
0.020
0.030
0.049
Total Area
Acres
0.015
0.034
0.049
Total Area
Acres
0.018
0.031
0.049
Total Area
Acres
0.013
0.028
0.041
Total Area
Acres
0.011
0.030
0.041
Total Area
Acres
0.013
0.028
0.041
Total Area
Acres
0.016
0.039
0.055
PERVIOUS PAYERS 115
~L_ _____________________________ ____::::====::::'.::::::====:::.._-------------------____:================================..J
n-
Attachment lb
Tabular Summary of DMAs and
Design Capture Volumes
Page intentionally blank
OMA SUMMARY
DMAID Type Total Area Total Area Runoff Factor C*A C Factor
SF Acres
DMA-1A Roof/Pavement 30,100 0.691 1.0 30,100
DMA-1B Landscape-B 8,044 0.185 0.1 804
DMA-1C Landscape-D 22,491 0.516 0.1 2,249
DMA-10 Pervious pavment 943 0.022 0.1 94
TOTAL 61 ,578 1.414 C= 33,248 0.54
DMAID Type Total Area Total Area Runoff Factor C*A C Factor
SF Acres
DMA-2A Pervious Pavement -Self Retaining 855 0.020 0.1 86
DMA-2B Landscape-Self Mitigating 1,297 0.030 0.1 130
TOTAL 2,152 0.049 C= 215 0.10
DMAID Type Total Area Total Area Runoff Factor C*A C Factor
SF Acres
DMA-3A Pervious Pavement -Self Retaining 655 0.015 0.1 66
DMA-3B Landscape-Self Mitigating 1,501 0.034 0.1 150
TOTAL 2,156 0.049 C= 216 0.10
DMAID Type Total Area Total Area Runoff Factor C*A C Factor
SF Acres
DMA-4A Pervious Pavement -Self Retaining 790 0.018 0.1 79
DMA-4B Landscape-Self Mitigating 1,365 0.031 0.1 137
TOTAL 2,155 0.049 C= 216 0.10
DMAID Type Total Area Total Area Runoff Factor C*A C Factor
SF Acres
OMA-SA Pervious Pavement -Self Retaining 558 0.013 0.1 56
DMA-5B Landscape-Self Mitigating 1,227 0.028 0.1 123
TOTAL 1,785 0.041 C= 179 0.10
DMAID Type Total Area Total Area Runoff Factor C*A C Factor
SF Acres
DMA-6A Pervious Pavement -Self Retaining 495 0.011 0.1 50
DMA-6B Landscape-Self Mitigating 1,290 0.030 0.1 129
TOTAL 1,785 0.041 C= 179 0.10
DMAID Type Total Area Total Area Runoff Factor C*A C Factor
SF Acres
DMA-7A Pervious Pavement -Self Retaining 558 0.013 0.1 56
DMA-7B Landscape-Self Mitigating 1,227 0.028 0.1 123
TOTAL 1,785 0.041 C= 179 0.10
DMAID Type Total Area Total Area Runoff Factor C*A C Factor
SF Acres
DMA-8A Pervious Pavement -Self Retaining 693 0.016 0.1 69
DMA-8B Landscape-Self Mitigating 1,720 0.039 0.1 172
TOTAL 2,413 0.055 C= 241 0.10
Attachment le
Harvest and Use Feasibility Screening
Page intentionally blank
Harvest and Use Feasibility Screening
The estimate anticipated average wet season demand over a period of 36 hours.
3 (residents per home) x 7 (homes) x 9.3 (flushes per resident)= 195.3 gal or 26.1 cf.
2.8 (avg. evapotranspiration) x [(0.2 plant factor x 44,740 SF landscape area)/ 90% irrigation
efficiency] x 0.015 = 417 cf
DCV per Worksheet B.2-1 = 1,660 cf.
ls the 36-hour demand greater than or equal to the DCV? NO
ls the 36-hour demand greater than 0.25DCV but less than the full DCV? NO
ls the 36-hour demand less than 0.25DCV? YES
Harvest and use is considered to be infeasible.
Page intentionally blank
Attachment ld
Form 1-8, Categorization of Infiltration Feasibility
Condition
Page intentionally blank
Appendix I: Forms and Checklists
A
Factor Category
Suitability
Assessment
Factor Description
Soil assessment methods
Predominant soil texture
Site soil variability
Depth to groundwater / impervious
layer
Assigned
Weight (w)
0.25
0.25
0.25
0.25
Suitability Assessment Sa fety Factor, SA = Ip
B Design
Level of pretreatment/
sediment loads
Redundancy/ resiliency
expected
Compaction during construction
Design Safety Factor, Ss = I p
Combined Safety Factor, S101a1 = SA x Ss
Observed Infiltration Rate, inch/hr, Kobscrvcd
(corrected for test-specific bias)
Design Infiltration Rate, in/hr, Nesign = Kobscrvcd / S,o,al
Supporting Data
Briefly describe infiltration test and provide reference to test forms:
0.5
0.25
0.25
Factor
Value (v)
2
2
2
1
1
2
1
Product (p)
p=wxv
0.50
0.50
0.50
0.25
1.75
0.50
0.50
0.25
1.25
2.19
0.20
0.09
See geotechnical report prepared by Geocon dated 1-17-18, Geotechnical
Report, "Appendix C" attached below.
Update letter dated 1-30-19 confirming applicability of design rate, attached below
I-7 February 2016
I I I
I
I I
I I
I
I '
I I
I 11
I I
I
GEOTECHNICAL INVESTIGATION
1534 MAGNOLIA AVENUE
CARLSBAD, CALIFORNIA
PREPARED FOR
ASTHON 3, LLC
RANCHO MISSION VIEJO, CALIFORNIA
JANUARY 17, 2018
PROJECT NO. G2192-52-01
GEOCON
INCORPORATED
GEOTECHNICAL ■
Project No. 02192-52-01
January 17, 2018
Ashton 3, LLC
5 Hoya Street
Rancho Mission Viejo, California 92694
Attention: Mr. Taylor Ashton
Subject: GEOTECHNICAL INVESTIGATION
1534 MAGNOLIA A VENUE
CARLSBAD, CALIFORNIA
Dear Mr. Ashton:
In accordance with your request, we performed this geotechnical investigation for the proposed 7-lot
residential development in Carlsbad, California. T he accompanying report presents the results of our
study and our conclusions and recommendations regarding the geotechnical aspects of project
development. The results of our study indicate that the site can be developed as planned, provided the
recommendations of this report are followed.
Should you have questions regarding this report, or if we may be of further service, please contact the
undersigned at your convenience.
Very truly yours,
GEOCON INCORPORATED
MRL:SFW :JH:dmc
(e-mail)
(3)
Addressee
Mr. Robert C. Ladwig
GE 2714
6960 Flanders Drive ■ San Diego, California 92121 -2974 ■ Telephone 858.558.6900 ■ Fax 858.558.6159
TABLE OF CONTENTS
1. PURPOSE AND SCOPE ................................................................................................................. I
2. SITE AND PROJECT DESCRIPTION ........................................................................................... 1
3. GEOLOGIC SETTING .................................................................................................................... 2
4. SOIL AND GEOLOGIC CONDITIONS ........................................................................................ 2
4.1 Undocumented Fill (Qudf) .................................................................................................... 2
4.2 Old Paralic Deposits (Qop) .................................................................................................... 2
5. GROUNDWATER .......................................................................................................................... 3
6. GEOLOGIC HAZARDS ................................................................................................................. 3
6.1 Faulting and Seismicity ......................................................................................................... 3
6.2 Ground Rupture ..................................................................................................................... 5
6.3 Liquefaction ........................................................................................................................... 5
6.4 Seiches and Tsunamis ............................................................................................................ 6
6.5 Landslides .............................................................................................................................. 6
7. CONCLUSIONS AND RECOMMENDATIONS ........................................................................... 7
7.1 General ................................................................................................................................... 7
7.2 Excavation and Soil Characteristics ...................................................................................... 8
7.3 Grading .................................................................................................................................. 9
7.4 Temporary Excavations ....................................................................................................... I 0
7.5 Seismic Design Criteria ....................................................................................................... I 0
7 .6 Shallow Foundations ........................................................................................................... 12
7. 7 Concrete Slabs-on-Grade ..................................................................................................... 13
7.8 Post-Tensioned Foundation System Recommendations ...................................................... 14
7 .9 Concrete Flatwork ............................................................................................................... 16
7.10 Retaining Walls ................................................................................................................... 17
7 .11 Lateral Loading .................................................................................................................... 18
7.12 Preliminary Pavement Recommendations ........................................................................... 19
7 .1 3 Site Drainage and Moisture Protection ................................................................................ 22
7.14 Grading, Improvement and Foundation Plan Review .......................................................... 22
LIMITATIONS AND UNIFORMITY OF CONDITIONS
MAPS AND ILLUSTRATIONS
Figure I, Vicinity Map
Figure 2, Geologic Map
Figure 3, Wall/Column Footing Dimension Detail
Figure 4, Typical Retaining Wall Drain Detai l
APPENDIX A
FIELD INYESTIGA TION
Figures A-1 -A-9, Exploratory Trench Logs
TABLE OF CONTENTS (Concluded)
APPENDIX B
LABORATORY TESTING
Table 8-I, Summary of Laboratory Maximum Density and Optimum Moisture Content Results
Table B-II, Summary of Laboratory Direct Shear Results
Table B-III, Summary of Laboratory Expansion Index Test Results
Table 8-IV, Summary of Laboratory Water-Soluble Sulfate Test Results
Table 8-V, Summary of Laboratory Resistance Value (R-Value) Test Results
Figure B-1, Gradation Curves
APPENDIX C
STORM WATER MANAGEMENT INVESTIGA TlON
APPENDIXD
RECOMMENDED GRADING SPECIFICATIONS
LIST OF REFERENCES
APPENDIX C
STORM WATER MANAGEMENT INVESTIGATION
FOR
1534 MAGNOLIA AVENUE
CARLSBAD, CALIFORNIA
PROJECT NO. G2192-52-01
APPENDIX C
STORM WATER MANAGEMENT INVESTIGATION
We understand storm water management devices wi ll be used in accordance with the BMP Design
Manual currently used by the City of Carlsbad. If not properly constructed, there is a potential for
distress to improvements and properties located hydrologically down gradient or adjacent to these
devices. Factors such as the amount of water to be detained, its residence time, and soil permeability
have an important effect on seepage transmission and the potential adverse impacts that may occur if
the storm water management features are not properly designed and constructed. We have not
performed a hydrogeological study at the site. If infiltration of storm water runoff occurs,
downstream properties may be subj ected to seeps, springs, slope instability, raised groundwater,
movement of foundations and slabs, or other undesirable impacts as a result of water infiltration.
Hydrologic Soil Group
The United States Department of Agriculture (USDA), Natural Resources Conservation Services,
possesses general information regarding the existing soil conditions for areas within the United
States. The USDA website also provides the Hydrologic Soil Group. Table C-1 presents the
descriptions of the hydrologic soil groups. If a soil is assigned to a dual hydrologic group (AID, BID,
or CID), the first letter is for drained areas and the second is for undrained areas. In addition, the
USDA website also provides an estimated saturated hydraulic conductivity for the existing soil.
TABLE C-1
HYDROLOGIC SOIL GROUP DEFINITIONS
Soil Group Soil Group Definition
Soils having a high infiltration rate (low runoff potential) when thoroughly wet. These consist
A mainly of deep, well drained to excessively drained sands or gravell y sands. These soi ls have a
high rate of water transmission.
Soils having a moderate infiltration rate when thoroughly wet. These consist chiefly of
B moderately deep or deep, moderately well drained or well drained soils that have moderately
fine texture to moderately coarse texture. These soil s have a moderate rate of water
transmission.
Soils having a slow infiltration rate when thoroughly wet. These consist chiefly of soils having a
C layer that impedes the downward movement of water or soils of moderately fi ne texture or fine
texture. These soils have a slow rate of water transmission.
Soi ls having a very slow infiltration rate (hi gh runoff potential) when thoroughly wet. These
D consist chiefly of clays that have a high shrink-swell potential, soils that have a high-water table,
soils that have a claypan or clay layer at or near the surface, and soils that are shallow over
nearly impervious material. These soils have a very slow rate of water transmission.
The property is underlain by natural materials consisting of undocumented fill and Old Paralic
Deposits and should be classified as Soil Group D. Table C-II presents the information from the
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USDA website for the subject property. The Hydro logic Soil Group Map, provided at the end of this
appendix, presents output from the USDA website showing the limits of the soil units.
TABLE C-11
USDA WEB SOIL SURVEY -HYDROLOGIC SOIL GROUP
Approximate ksAT of
Map Unit Name Map Unit Percentage Hydrologic Most Limiting
Symbol of Property Soil Group Layer
(inches/hour)
Chesterton-Urban Land Complex, CgC 83 D 0.00 -0.06 2 to 9 percent slopes
Marina Loamy Coarse Sand, MIC 17 B 0.57 -1.42 2 to 9 percent slopes
In-Situ Testing
The infiltration rate, percolation rates and saturated hydraulic conductivity are different and have
different meanings. Percolation rates tend to overestimate infiltration rates and saturated hydraulic
conductivities by a factor of 10 or more. Table C-III describes the differences in the definitions.
TABLE C-111
SOIL PERMEABILITY DEFINITIONS
Term Definition
The observation of the flow of water through a material into the ground
Infiltration Rate downward into a given soil structure under long term conditions. This is
a function of layering of soil, density, pore space, discontinuities and
initial moisture content.
The observation of the flow of water through a material into the ground
Percolation Rate downward and laterally into a given soil structure under long term
conditions. This is a function of layering of soil, density, pore space,
discontinuities and initial moisture content.
The volume of water that will move in a porous medium under a
Saturated Hydraulic hydraulic gradient through a unit area. This is a function of density,
Conductivity (ksAT, Permeability) structure, stratification, fines content and discontinuities. It is also a
function of the properties of the liquid as well as of the porous medium.
The degree of soil compaction or in-situ density has a significant impact on soil permeability and
infiltration. Based on our experience and other studies we performed, an increase in compaction
results in a decrease in soil permeability.
We performed 2 percolation tests within Trenches T-2 and T-3 at the locations shown on the attached
Geologic Map, Figure 2. The results of the tests provide parameters regarding the percolation rate and
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the saturated hydraulic conductivity/infiltration characteristics of on-site soil and geologic units.
Table C-IV presents the results of the estimated field saturated hydraulic conductivity and estimated
infiltration rates obtained from the percolation tests. The calculation sheets are attached herein. We
used a factor of safety applied to the test results on the worksheet values. The designer of storm water
devices should apply an appropriate factor of safety. Soil infiltration rates from in-situ tests can vary
significantly from one location to another due to the heterogeneous characteristics inherent to most
soil. Based on a discussion in the County of Riverside Design Handbook for Low Impact
Development Best Management Practices, the infiltration rate should be considered equal to the
saturated hydraulic conductivity rate.
TABLE C-IV
FIELD PERMEAMETER INFILTRATION TEST RESULTS
Test Depth Geologic Percolation Field-Saturated C.4-1 Worksheet
Test Location Rate Infiltration Rate, Infiltration Rate1, (feet) Unit (minutes/inch) ksat (inch/hour) ksat (inch/hour)
P-1 (T-2) 6 Qop 187.5 0.07 0.04
P-2 (T-3) 6 Qop 106.0 0.32 0.16
Average: 146.8 0.20 0.10
1 Using a factor of safety of 2.
Infiltration categories include full infiltration, partial infiltration and no infiltration. Table C-V
presents the commonly accepted definitions of the potential infiltration categories based on the
infiltration rates.
Infiltration Category
Full Infiltration
Partial Infiltration
No Infiltration (Infeasible)
1 Using a Factor of Safety of 2.
Groundwater Elevations
TABLE C-V
INFILTRATION CATEGORIES
Field Infiltration Rate, I
(inches/hour)
I > 1.0
0.10 <1_:S l.0
l <0.10
Factored Infiltration Rate1, I
(inches/hour)
I > 0.5
o.o5 < r .:s o.5
l < 0.05
We did not encounter groundwater or seepage during the site investigation. We expect groundwater
exists at depths greater than 50 feet below existing grades.
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New or Existing Utilities
Utilities will be constructed within the site boundaries. Full or partial infiltration should not be
allowed in the areas of the utilities to help prevent potential damage/distress to improvements.
Mitigation measures to prevent water from infi ltrating the utilities consist of setbacks, installing
cutoff wall s around the utilities and installing subdrains and/or installing liners. The horizontal and
vertical setbacks for infiltration devices should be a minimum of 10 feet and a I: I plane of I foot
below the closest edge of the deepest adjacent utility, respectively.
Existing and Planned Structures
Existing residential and roadway structures exist adjacent to the site. Water should not be allowed to
infiltrate in areas where it could affect the neighboring properties and existing adjacent structures,
improvements and roadway. Mitigation for existing structures consists of not allowing water
infiltration within a lateral distance of at least 10 feet from the new or existing fo undations.
Slopes Hazards
Slopes are not currently planned or exist on the property that would be affected by potential infiltration
locations. Therefore, infiltration in regards to slope concerns would be considered feasible.
Storm Water Evaluation Narrative
As discussed herein, the property consists of existing undocumented fill overlying Old Paralic
Deposits (Qop). Water should not be allowed to infiltrate into the undocumented or compacted fi ll
within the basins as it will allow for lateral migration to adjacent residences. We evaluated the
infiltration rates within the Old Paralic Deposits within the proposed basin areas to help evaluate if
infiltration is feasible.
We performed the infiltration tests at location where the basins would be practical based on the
topography of the property and discussions with the Client. We performed the percolation tests at the
lower elevations of the property and adjacent to the existing storm drain system. Our in-place
infiltration tests indicate an average of 0.10 inches/hour (including a factor of safety of 2); therefore,
the site is considered feasible for partial infiltration.
We do not expect geologic hazards to exist on the property. Therefore, partial infiltration may be
considered feasible within the Old Paralic Deposits.
Storm Water Management Devices
Liners and subdrains should be incorporated into the design and construction of the planned storm
water devices. The liners should be impermeable (e.g. High-density polyethylene, HOPE, with a
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thickness of about 30 mil or equivalent Polyvinyl Chloride, PVC) to prevent water migration. The
subdrains should be perforated within the liner area, installed at the base and above the liner, be at
least 3 inches in diameter and consist of Schedule 40 PVC pipe. The subdrains outside of the liner
should consist of solid pipe. The penetration of the liners at the subdrains should be properly
waterproofed. The subdrains should be connected to a proper outlet. The devices should also be
installed in accordance with the manufacturer's recommendations. Liners should be installed on the
side walls of the proposed basins in accordance with a partial infiltration design.
Storm Water Standard Worksheets
The BMP Design Manual requests the geotechnical engineer complete the Categorization of
Infiltration Feasibility Condition (Worksheet C.4-1 or I-8) worksheet information to help evaluate the
potential for infiltration on the property. The attached Worksheet C.4-1 presents the completed
information for the submittal process.
The regional storm water standards also have a worksheet (Worksheet D.5-1 or Form 1-9) that helps
the project civil engineer estimate the factor of safety based on several factors. Table C-VI describes
the suitability assessment input parameters related to the geotechnical engineering aspects for the
factor of safety determination.
TABLE C-VI
SUITABILITY ASSESSMENT RELATED CONSIDERATIONS FOR INFILTRATION FACILITY
SAFETY FACTORS
Consideration High Medium Low
Concern -3 Points Concern -2 Points Concern -1 Point
Use of soi l survey maps or Use of well permeameter
or borehole methods with simple texture analysis to accompanying Direct measurement with
estimate short-term localized (i.e. small-
infiltration rates. Use of continuous boring log. scale) infiltration testing Direct measurement of
Assessment Methods well permeameter or infiltration area with methods at relatively high
borehole methods without localized infiltration resolution or use of
accompanying continuous measurement methods extensive test pit
boring log. Relatively (e.g., Infiltrometer). infiltration measurement
sparse testing with direct Moderate spatial methods.
infiltration methods resolution
Predominant Soil Silty and clayey soils Loamy soils Granular to slightly
Texture with significant fines loamy soils
Highly variable soils Soil boring/test pits Soil boring/test pits indicated from site Site Soil Variability assessment or unknown indicate moderately indicate relatively
variability homogenous soils homogenous soils
Depth to Groundwater/ <5 feet below 5-15 feet below >15 feet below
Impervious Layer faci lity bottom facility bottom facility bottom
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Based on our geotechnical investigation and the previous table, Table C-VII presents the estimated
factor values for the evaluation of the factor of safety. This table only presents the suitability
assessment safety factor (Part A) of the worksheet. The project civil engineer should evaluate the
safety factor for design (Part B) and use the combined safety factor for the design infiltration rate.
TABLE C-Vll
FACTOR OF SAFETY WORKSHEET DESIGN VALUES -PART A1
Suitability Assessment Factor Category Assigned Factor Product
Weight (w) Value (v) (p = W X Y)
Assessment Methods 0.25 2 0.50
Predominant Soil Texture 0.25 2 0.50
Site Soil Variability 0.25 2 0.50
Depth to Groundwater/ Impervious Layer 0.25 l 0.25
Suitability Assessment Safety Factor, SA = LP 1.75
1 The project civil engineer should complete Worksheet D.5-1 or Form I-9 using the data on this table.
Additional information is required to evaluate the design factor of safety.
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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
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:
Yes No
X
Based on the USGS Soil Survey, the property possesses Hydrologic Soi l Group D classifications. In addition, we
encountered field infiltration rates of:
T-2/P-1: 0.07 inches/hour (0.04 with a FOS of2.0)
T-3/P-2: 0.32 inches/hour (0 .16 with a FOS of2.0)
This results in an average infiltration rate of 0.20 inches/hour (0 . IO with an FOS of 2.0).
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:
X
Undocumented fill and Old Paralic Deposits underlie the property. Water that would be allowed to infiltrate could
migrate laterally outside of the property limits to the existing right-of-ways (located to the south and west) and
toward existing and proposed structures (located to the north and east). However, we expect the basins would be
setback a sufficient distance from the existing and proposed utilities and structures to help alleviate seepage and
underground utility concerns. Additionally, the use of vertical cutoff walls or liners, as recommended herein, would
prevent lateral migration of water. The bottom of the basins should expose Old Paralic Deposits.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/ data source applicability.
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Criteria
3
Provide basis:
Screening Question
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.
Yes No
X
We did not encounter groundwater during the drilling operations on the property. We anticipate that groundwater is
present at depths of greater than 50 feet. Therefore, infiltration due to groundwater elevations would be considered
feasible. Additionally, we understand that contaminated soil or groundwater has not been documented or identified
at the property. Therefore, infiltration due to groundwater concerns would be considered feasible.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/ data source applicability.
4
Provide basis:
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.
X
We do not expect full infiltration would cause water balance issues including change of ephemeral streams or
discharge of contaminated water to surface waters.
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
Not Full
Infiltration
*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 to substantiate findings.
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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
5
Provide basis:
Screening Question
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.
Yes
X
No
Based on the USGS Soil Survey, the property possesses Hydro logic Soil Group D classifications. In addition, we
encountered fi eld infiltration rates of:
T-2/P-l : 0.07 inches/hour (0.04 with a FOS of 2.0)
T-3/P-2: 0.32 inches/hour (0.16 with a FOS of 2.0)
This results in an average infi ltration rate of 0.20 inches/hour (0.10 with an FOS of 2.0).
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
Provide basis:
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.
X
Undocumented fill and Old Paralic Deposits underlie the property. Water that would be allowed to infiltrate could
migrate laterally outside of the pro perty limits to the existing right-of-ways (located to the south and west) and
toward existing and proposed structures (located to the north and east). However, we expect the bas ins would be
setback a sufficient distance from the existing and proposed utilities and structures to help alleviate seepage and
underground utility concerns. Additionally, the use of vertical cutoff walls or liners, as recommend ed herein, would
prevent lateral mi gration of water. The bottom of the basins should expose Old Paralic Deposits.
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.
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Criteria
7
Provide basis:
Screening Question
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.
Yes No
X
We did not encounter groundwater during the drilling operations on the property. We anticipate that groundwater is
present at depths of greater than 50 feet. Therefore, infiltration due to groundwater elevations would be considered
feasible. Additionally, we understand that contaminated soil or groundwater has not been documented or identified
at the property. Therefore, infiltration due to groundwater concerns would be considered feasible.
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
Provide basis:
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.
X
We did not provide a study regarding water rights. However, these rights are not typical in the San Diego area.
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.
Part2
Result*
If all answers from row 1-4 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.
Partial
Infiltration
*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 to substantiate findings.
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OaEocoN
Excavation Percolation Test
Project Name: 1534 Magnolia Date: 9/27/2017 ---------Project Number: G2192-52-01 By: JML
Open-Pit Location: ---T---2...,.(P ___ l.,...) __ _ ---------
Test Hole Length (in.) 14.0 -----Test Hole Width (in.) 12.0 --------'--_;_----or
Test Hole Dia. (in.)
Test Hole Depth (in.) 10.5 Test Hole Area, A, (in. 2) 168.0 -----
t.t lt.D t:,.v/6.t (Q/A}*60
Depth of Cumulative Wetted Change in Percolation Flow Rate, Infiltration
Reading Time, t Water, D '1t(min) Time, t MJ (in.) Area, A wet Volume, Rate Q Rate, / t
(min) (in.) (min) (in .2) /':,. V (in.3) (min/in.) (in.3/min) (in./hr)
1 0.0 8.25 15.00 15.00 0.06 595.38 10.50 240.00 0.70 0.07 15.0 8.19
2 0.0
15.0
8.50
8.49 15.00 30.00 0.01 609.74 1.68 1500.00 0.11 0.01
3 0.0 8.50 15.00 45.00 0.25 603.50 42.00 60.00 2.80 0.28 15.0 8.25
4 0.0
15.0
8.50
8.49 15.00 60.00 0.01 609.74 1.68 1500.00 0.11 0.01
5 0.0 8.50 15.00 75.00 0.01 609.74 1.68 1500.00 0.11 0.01 15.0 8.49
6 0.0
15.0
8.50
8.44 15.00 90.00 0.06 608.38 10.50 240.00 0.70 0.07
7 0.0
15.0
9.00
8.99 15.00 105.00 0.01 635.74 1.68 1500.00 0.11 0.01
8 0.0 9.00 15.00 120.00 0.06 634.38 10.50 240.00 0.70 0.07 15.0 8.94
9 0.0
15.0
9.00
8.99 15.00 135.00 0.01 635.74 1.68 1500.00 0.11 0.01
10 0.0 9.00 15.00 150.00 0.07 634.18 11.76 214.29 0.78 0.07 15.0 8.93
11 0.0
15.0
9.00
8.92 15.00 165.00 0.08 633.92 13.44 187.50 0.90 0.08
12 0.0 9.25 15.00 180.00 15.0 9.20 0.05 647.70 8.40 300.00 0.56 0.05
13
14
2.00 QJ ... ra 1.50 Cl:
C ...
0 .s:: 1.00 ·-....... ... ra C ... ·-.::-0.50 .;::
.!: ...... 0.00 -----~... ~·---•-----'• .... --•----••-,,,,...-....... ---1•..---•------·
0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00 160.00 180.00 200.00
Time (min)
Percolation Rate (Minutes/Inch) = 187.5
0.07 Soil Infiltration Rate (Inches/Hour)
e>GEOCON
Excavation Percolation Test
Project Name: __ l_S_3_4_M_a....;g;;...n_o_li_a __
Project Number: G2192-52-01
Open-Pit Location: ---T---3"""(-P--2.,..) ---
Test Hole Length (in.) 14.0 -----
Test Hole Width (in.) 12.0 --------'--.;._----or
Test Hole Dia. (in.)
Test Hole Depth (in.)
Depth of Time, t Reading Water, D b.t (min) (min) (in.)
1 0.0 8.50 15.00 15.0 8.00
2 0.0 8.50 15.00 15.0 8.44
3 0.0 8.50 15.00 15.0 8.38
4 0.0 8.50 15.00 15.0 8.49
5 0.0 8.50 15.00 15.0 8.00
6 0.0 8.19 15.00 15.0 8.00
7 0.0 8.50 15.00 15.0 8.06
8 0.0 8.50 15.00 15.0 8.44
9 0.0 8.75 15.00 15.0 8.44
10 0.0 8.75 15.00 15.0 8.25
11 0.0 8.25 15.00 15.0 8.19
12
13
14
2.00 QJ +' ro 1.50 er::
C: ,_
0 .s:: 1.00 ·-...... +' ro c: ,_ ·-±: -0.50 ..:: .: 0.00
0.00 20.00 40.00
Percolation Rate (Minutes/Inch)
Soil Infiltration Rate (Inches/Hour)
11.0
Cumulative
Time,t
(min)
15.00
30.00
45.00
60.00
75.00
90.00
105.00
120.00
135.00
150.00
165.00
60.00
=
/ill (in.)
a.so
0.06
0.13
0.01
a.so
0.19
0.44
0.06
0.31
0.50
0.06
80.00
Time (min)
Date: 9/27/2017
By: JML
Test Hole Area, A, (in .2) 168.0 -----
.6.t /.6.D t,.v/1::i.t (Q/A)*60
Wetted Change in Percolation Flow Rate, Infiltration
Area, A wet Volume, Rate Q Rate, It
(in.2) !J. V (in.3) (min/in.) (in.3/min) (in./hr)
597.00 84.00 30.00 5.60 0.56
608.38 10.50 240.00 0.70 0.07
606.75 21.00 120.00 1.40 0.14
609.74 1.68 1500.00 0.11 0.01
597.00 84.00 30.00 5.60 0.56
588.88 31.50 80.00 2.10 0.21
598.63 73.50 34.29 4.90 0.49
608.38 10.50 240.00 0.70 0.07
614.88 52.50 48.00 3.50 0.34
610.00 84.00 30.00 5.60 0.55
595.38 10.50 240.00 0.70 0.07
100.00 120.00 140.00 160.00 180.00
106.0
0.32
t
N
HYDROLOGIC SOIL SURVEY
GEOCON
INCORPORAT ED
GEOTECHNICAL ■ ENVIRONMENTAL ■ MATERIALS
6960 FLANDERS DRIVE -SAN DIEGO, CALIFORNIA 92121 -297 4
PHONE 858 558-6900-FAX 858 558-6159
ML /CW I I DSK/GTYPD
1534 MAGNOLIA AVENUE
CARLSBAD, CALIFORNIA
DATE 01 -17 -2018 l PROJECT NO.G2192 -52-01 I FIG. C-1
Plotted:01/17/2018 8:10AM I By:JONATHAN WILKINS I FIie Locatlon:Y:IPROJECTS\G2192-52-01 1534 Magnolla Ave\DETAILSIG2192-52-01_HydrologlcSo11Survey.dwg
GEOCON
INCORPORATED
GEOTECHNICAL ■ ENVIRONMENTAL ■
Project No. 02192-52-0 I
January 30, 2019
Ashton 3, LLC
5 Hoya Street
Rancho Mission Viejo, California 92694
Attention: Mr. Taylor Ashton
Subject: RESPONSE TO CITY COMMENTS
1534 MAGNOLIA A VENUE
CARLSBAD, CALIFORNIA
References: 1. Geotechnical Investigation, 1534 Magnolia Avenue, Carlsbad, California, prepared
by Geocon Incorporated, dated January 17, 2017 (Project No. 02192-52-01 ).
2. Preliminary Permeable Pavement Recommendations, 1534 Magnolia Avenue,
Carlsbad, California, prepared by Geocon Incorporated, dated May 21, 2018
(Project No. 02192-52-01).
3. Grading Plans for Magnolia-Brady, 1534 Magnolia Avenue, Carlsbad, California,
prepared by Civil Landworks, dated November 27, 2018 (Drawing No. 515-3A).
4. Grading Plans -Plancheck #1 for "Magnolia-Brady", 1534 Magnolia Avenue,
Carlsbad, California, prepared by City of Carlsbad, dated January 25, 2019 (City
Project ID CT 2018-0003).
Dear Mr. Ashton:
We prepared this letter to address the referenced review comments provided by the City of Carlsbad for
the subject development. The reviewer's comments are listed herein with our response immediately
following.
Comment 1:
Response:
Comment 2:
Response:
Provide recommendations for permeable pavers.
We provided recommendations for permeable pavers in our letter dated May 21 ,
2018 for the proposed development (see Reference 2). A copy of that letter has
been appended herein.
Infiltration testing was conducted during outdated BMP layout. Provide a letter
verifying infiltration design rate is still applicable.
Based on our review of the project plans and the information contained within the
referenced geotechnical documents, we opine the plans and details have been
6960 Flanders Drive ■ Son Diego, California 92121-297 4 ■ Telephone 858.558.6900 ■ Fox 858.558.6 159
prepared in substantial conformance with the recommendations presented in the
referenced geotechnical reports. The recommendations and conclusions in the
referenced investigation remain valid for the proposed improvements, including
our recommendations regarding storm water BMP design. The design infiltration
rate we provided in the geotechnical documents remains applicable for the design
of the project.
We limited our review to geotechnical aspects of project development and the
review did not include other details on the referenced plans. Geocon Incorporated
has no opinion regarding other details found on the referenced plans, structural or
otherwise, that do not directly pertain to geotechnical aspects of site development.
If you have any questions regarding this correspondence, or if we may be of further service, please
contact the undersigned at your convenience.
Very truly yours,
GEOCONINCORPORATED
)lOL
Shawn Foy Weedon
GE 2714
MRL:dmc
Attachment: Preliminary Permeable Pavement
Recommendations Letter, dated May 21 , 2018
(e-mail) Addressee
(e-mail) Mr. Dave Lother
Project No. G2 I 92-52-0 I -2 -January 30, 2019
Attachment le
Pollution Control BMP Design
Worksheets/ Calculations
Page intentionally blank
Appendix B: Storm Water Pollutant Control H ydrologic Calculations and Sizing Methods
Worksheet B.2-1 DCV -DMA-1
•·
1 8S,1i percentile 24-hr storm depth from Figure B.1-1 d= 0.6 inches
2 Area tributary to BMP (s) A= 1.452 acres
3 Area weighted runoff factor (estimate using Appendix B.1.1 and B.2.1) C= 0.53 unitless
4 Tree wells volume reduction TCV= 0 cubic-feet
5 Rain barrels volume reduction RCV= 0 cubic-feet
6 Calculate DCV = (3630 x C x d x A) -TCV -RCV DCV= 1,676 cubic-feet
Storm \v'ater Standards
January 2016 Edition B-10
Appendix B: Storm Water Pollutant Control Hydrologic Calculations and Sizing Methods
Worksheet B.5-1: Simple Sizing Method for Biofiltration BMPs -DMA-1 ... --... --' 1n ~ filiiTITI lU'iTW: t , ■ .....
Remaining DCV after implementing retention BMPs 1,676
Partial Retention
2 Infiltration rate from Form 1-9 if partial infiltration is feasible 0.09
3 Allowable drawdown time for aggregate storage below the underdrain 36
4 Depth of runoff that can be infiltrated rLine 2 x Line 31 3.24
5 Aggregate pore space 0.40
6 Required depth of gravel below the underdrain rLine 4/ Line 51 8.1
7 Assumed surface area of the biofiltration BMP 1200
8 Media retained pore storage 0.1
9 Volume retained by BMP [[Line 4 + (Line 12 x Line 8)]/12] x Line 7 504
10 DCV that requires biofiltration [Line I -Line 9] 1,172
BMP Parameters
11 Surface Ponding r6 inch minimum, 12 inch maximuml 12
12 Media Thickness [18 inches minimum], also add mulch layer thickness to 18 this line for sizing calculations
13 Aggregate Storage above underdrain invert ( 12 inches typical) -use 0 inches
for sizing if the aggregate is not over the entire bottom surface area 3
14 Media available pore space 0.2
15 Media filtration rate to be used for sizing (5 in/hr. with no outlet control; if the
filtration is controlled by the outlet, use the outlet controlled rate) 5.00
Baseline Calculations
16 Allowable Routing Time for sizing 6
17 Depth filtered during storm [ Line 15 x Line 16] 30.00
18 Depth of Detention Storage
[Line 11 + (Line 12 x Line 14) + (Line 13 x Line 5)] 16.8
19 Total Depth Treated [Line 17 + Line 18] 46.80
Option 1-Biofilter "1.5" times the DCV
20 Required biofiltered volume [1.5 x Line 10] 1758.15
21 Required Footprint rLine 20/ Line 191 x 12 45 1
Option 2 -Store 0.75 of remaining DCV in pores and ponding
22 Required Storage (surface + pores) Volume ro .75 x Line 101 879.07626
23 Required Footprint [Line 22/ Line 18] x 12 628
Footprint of the BMP
24 Area draining to the BMP 63,234
25 Adjusted Runoff Factor for drainage area (Refer to Appendix B. l and B.2) 0.53
26 Minimum BMP Footprint [Line 24 x Line 25 x 0.03] 1,005
27 Footprint of the BMP = Maximum(Minimum(Line 21 , Line 23), Line 26) 1,150
cubic-
feet
in/hr.
hours
inches
in/in
inches
sq-ft
in/in
cubic-
feet
cubic-
feet
inches
inches
inches
in/in
in/hr.
hours
inches
inches
inches
cubic-feet
sq-ft
cubic-feet
sq-ft
sq-ft
sq-ft
sq-ft
DRAW DOWN for Biofiltration Basin
Infiltration rate 0.09 inches/ hour I
Qout =AV= A acres• 43560 sf/Acre (infiltration rate in/hr)* 1fl/12in (1 hr/3600 sec)
Orifice Flow:
g=
C=
Orifice-1
No. of openings
Elevation
diameter
A=
Water De11th (ftl
100.00
102.50
103.83
Q = C *A* sqrt(2gh)
32.20 sf/sec
0.60
100.67
4.6
0.12
Volume (c!J
0
47,150
120,443
inches
sf
Stage Storage
Area (Ac.ft}
0.000
1.082
2.765
0.38
Area of
Infiltration (ft}
N/A
1,150
1.150
Rate through Media = Q cfs • 12 in/fl• 3600 sec/ hour/ 1150 sf
fl
Q infill.
0.000
0.002
0.002
Effective Head Q_£fl! Q total Rate media
Orifice-1 Orifice-1 Q inf + Q orifice in/hr
NIA 0.00 0.000 0.00
1.64 0.71 0.714 27.19
2.97 0.96 0.960 36.56
BLANK PAGE
Attachment 2
BACKUP FOR PDP
HYDROMODIFICATION CONTROL MEASURES
Page intentionally blank
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 Contents Checklist
Sequence
Attachment 2a Hydromodification Management □ Included
Exhibit (Required)
See Hydromodification Management
Exhibit Checklist on the back of this
Attachment cover sheet.
Attachment 2b Management of Critical Coarse 1:8:1 Exhibit showing project drainage
Sediment Yield Areas (WMAA Exhibit boundaries marked on WMAA Critical
is required, additional analyses are Coarse Sediment Yield Area Map
optional) (Required)
See Section 6.2 of the BMP Design Optional analyses for Critical Coarse
Manual. 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 1:8:1 Not performed
Channels (Optional) □ Included
See Section 6.3.4 of the BMP Design
Manual.
Attachment 2d Flow Control Facility Design and 1:8:1 Included
Structural BMP Drawdown
Calculations (Required)
See Chapter 6 and Appendix G of the
BMP DesiQn Manual
Use this checklist to ensure the required information has been included on the
Hydromodification Management Exhibit:
The Hydromodification Management Exhibit must identify:
D Underlying hydrologic soil group
D Approximate depth to groundwater
o Existing natural hydrologic features ( watercourses, seeps, springs, wetlands)
D Critical coarse sediment yield areas to be protected (if present)
D Existing topography
o Existing and proposed site drainage network and connections to drainage offsite
D Proposed grading
D Proposed impervious features
D Proposed design features and surface treatments used to minimize imperviousness
D Point(s) of Compliance (POC) for Hydromodification Management
o Existing and proposed drainage boundary and drainage area to each POC (when necessary,
create separate exhibits for pre-development and post-project conditions)
D Structural BMPs for hydromodification management (identify location, type of BMP, and
size/detail)
Attachment 2a
Hydromodification Management Exhibit
N/A
Page intentionally blank
I
I
~
I
Legend
Watershed Boundaries
Q Municipal Boundaries
-Regional WMAA Streams
-Exempt Bodies:
Waler Storage Reservoirs, Lakes,
Enclosed Embaymenls, Pacific
Ocean, Buena Vista Lagoon
4!!!!!!!!!!!!!!Exempt River Reaches:
Reaches of San Luis Rey River, San
Dleguilo River, San Diego River,
Forester Creek, Sweetwater River,
Olay River
-Exempt Conveyance Systems:
Existing underground storm drains or
conveyance channels whose bed
and bank are concrete-lined,
discharging directly lo exempt waler
bodies, exempt rivers, or localized
areas of Agua Hedionda Lagoon and
Baliquilos Lagoon
Carlsbad Watershed Management Area
HU 904.00, 211 mi2
Receiving Waters and Conveyance Systems Exempt
from Hydromodification Management Requireme_nts
0 2.5 5
Exhibit Date: Sept. 8, 2014
Geosyntec P
consultants
RICK
.:1.,i;-
--·-~=-~
,;
Miles IT!
10 LU
a
E.\JGlt.'.EERl'lG COMPANY ~
Attachment 2b
Management of
Critical Coarse Sediment Yield Areas
Page intentionally blank
POTENTIAL CRITICAL
COARSE SEDIMENT YIELD
AREA
POTENTIAL CRITICAL
COARSE SEDIMENT YIELD
AREA
iiif.lE
Page intentionally blank
Attachment 2c
Geomorphic Assessment of Receiving Channels
N/A
Page intentionally blank
Attachment 2d
Flow Control Facility Design
NIA
Page intentionally blank
ATTACHMENT 3
Structural BMP Maintenance Thresholds and Actions
Page intentionally blank
Operation and Maintenance Plan for the Stormwater Quality BMP Facilities
for
MAGNOLIA-BRADY -SWQMP
May 2, 2019
I. PURPOSE
The primary purpose of this Operations & Maintenance Plan (O&M Plan) shall be to
provide a routine maintenance program that maintains the treatment facilities
effectiveness.
II. COVERAGE AREA
This project will utilize 1 primary treatment facility type and a secondary treatment
structure located on-site:
1. Biofiltration Basin -located along the easterly property line.
2. Pervious pavement -located in driveways for the 7 lots.
The biofiltration basin will treat stormwater runoff from the site and outlet it into the
public storm system on Brady Circle. The pervious pavement will treat any surface
runoff and provide a little volume for water storage beneath the surface. A perforated
pipe will be place below the pervious pavement to collect storm water and discharge it
into Brady Circle via sidewalk underdrains.
Ill. ROUTINE MAINTENANCE ACTIVITIES
Primary maintenance activities include vegetation management, trash and sediment
removal, irrigation maintenance and storm drain outlet inspections. The basins and
swales are designed to fully drain within 24-72 hours and not include permanent pools
or standing water. Routine maintenance activities, and the frequency at which they will
be conducted, are shown in Table 1 below.
NOTE: Landscape Maintenance Plan should also be reviewed for consistency with vegetation
maintenance and any applicable needs for specific plants, shrubs or trees.
Page 1
Table 1
Routine Maintenance Activities for Basins & Swales
No. Maintenance Task Frequency of Task
Conduct annual vegetation management during the summer,
1 removing weeds and harvesting vegetation. Remove all grass Once a year
cuttings and other green waste.
Trim vegetation at beginning and end of wet season to prevent
2 establishment of woody vegetation, and for aesthetics and Twice a year (spring and fall)
mosquito control.
3 Evaluate health of vegetation and remove or replace any dead or Twice a year dying plants. Remove all green waste and dispose of properly.
If turf grass is included in basin/swale design, conduct regular As necessary to not allow grass 4 mowing and remove all grass cuttings. Avoid producing ruts over-growth when mowing.
7 Remove accumulated trash and debris from the middle and end Twice a year (January and April) of the wet season and dispose of trash and debris properly.
8 Irrigate during dry weather. Per Landscape Plans
9 Inspect basins and swales using the attached inspection Quarterly, or as needed checklists.
IV. PROHIBITIONS
The use of pesticides and quick release fertilizers shall be minimized , and the principles
of integrated pest management (1PM) followed :
1. Employ non-chemical controls (biological, physical and cultural controls)
before using chemicals to treat a pest problem.
2. Prune plants properly and at the appropriate time of year.
3. Provide adequate irrigation for landscape plants. Do not over water.
4. Limit fertilizer use unless soil testing indicates a deficiency. Slow-release or
organic fertilizer is preferable. Check with municipality for specific
requirements.
5. Pest control should avoid harming non-target organisms, or negatively
affecting air and water quality and public health. Apply chemical controls only
when monitoring indicates that preventative and non-chemical methods are
not keeping pests below acceptable levels. When pesticides are required,
apply the least toxic and the least persistent pesticide that will provide
adequate pest control. Do not apply pesticides on a prescheduled basis.
6. Sweep up spilled fertilizer and pesticides. Do not wash away or bury such
spills.
7. Do not over apply pesticide. Spray only where the infestation exists. Follow
the manufacturer's instructions for mixing and applying materials.
8. Only licensed , trained pesticide applicators shall apply pesticides.
Page 2
9. Apply pesticides at the appropriate time to maximize their effectiveness and
minimize the likelihood of discharging pesticides into run off. With the
exception of pre-emergent pesticides, avoid application if rain is expected.
10. Unwanted/unused pesticides shall be disposed as hazardous waste.
V. INSPECTIONS
The attached Inspection and Maintenance Checklists shall be used to conduct
inspections monthly (or as needed), identify needed maintenance, and record
maintenance that is conducted.
Page 3
Basin Inspection and Maintenance Checklist
Property Address: __________________ _ Property Owner: _______________ _
Treatment Measure No.: Date of Inspection: Type of Inspection: □ Monthly □ Pre-Wet Season
□ After heavy runoff □ End of Wet Season
lnspector(s): □ Other: ______ _
Defect Conditions When Maintenance Comments (Describe maintenance Results Expected When Maintenance Is Performed
Maintenance Is Needed Needed? (Y/N) completed and if any needed maintenance was
not conducted, note when ii will be done.)
General
Trash & • Trash and debris Trash and debris cleared from site and disposed of
Debris accumulated in basin. properly.
• Visual evidence of
dumping.
Poisonous Poisonous or nuisance Use Integrated Pest Management techniques to control
Vegetation vegetation or noxious noxious weeds or invasive species.
and noxious weeds, e.g., morning glory,
weeds English ivy, reed canary
grass, Japanese knotweed,
purple loosestrife,
blackberry, Scotch broom,
poison oak, stinging nettles,
or devil's club.
Contaminants Any evidence of oil, No contaminants or pollutants present.
and Pollution gasoline, contaminants or
other pollutants.
Rodent Holes If facility acts as a dam or The design specifications are not compromised by
berm , any evidence of holes.
rodent holes, or any Any rodent control activities are in accordance with evidence of water piping applicable laws and do not affect any protected through dam, berm or into species. slopes via rodent holes.
Insects Insects such as wasps and Insects do not interfere with maintenance activities.
hornets interfere with
maintenance activities.
Page 4
Basin & Swales Inspection and Maintenance Checklist Date of Inspection: _______ _
Property Address: __________ _ Treatment Measure No.: _______ _
Defect Conditions When Maintenance Comments (Describe maintenance Results Expected When Maintenance Is Performed
Maintenance Is Needed Needed? (Y/N) completed and if any needed maintenance was
not conducted , note when it will be done.)
Tree/Brush • Growth does not allow • Trees do not hinder maintenance activities.
Growth and maintenance access or • Remove hazard trees as approved by the City . Hazard Trees interferes with
maintenance activity. (Use a certified Arborist to determine health of tree
• Dead, diseased, or dying or removal requirements).
trees/shrubs.
Drainage time Standing water remains in Correct any circumstances that restrict the flow of water
basin more than five days. from the system. Restore drainage to design condition.
If the problem cannot be corrected and problems with
standing water recur, then mosquitoes should be
controlled with larvicides, applied by a licensed
pesticide applicator.
Outfall Debris or silt build-up Remove debris and/or silt build-up and dispose of
structure obstructs an outfall structure. properly.
Side Slopes
Erosion • Eroded over 2 in. deep Cause of erosion is managed appropriately. Side
where cause of damage is slopes or berm are restored to design specifications, as
still present or where there needed.
is potential for continued
erosion.
• Any erosion on a
compacted berm
embankment.
Storage Area
Sediment Accumulated sediment Sediment cleaned out to designed basin shape and
>10% of designed basin depth; basin reseeded if necessary to control erosion.
depth or affects inletting or Sediment disposed of properly.
outletting condition of the
facility.
Liner (If Liner is visible and has more Liner repaired or replaced. Liner is fully covered.
Applicable) than three 1/4-inch holes in
it.
Emergency Overflow/ Spillway and Berms
Settlement Berm settlement 4 inches Dike is built back to the design elevation.
lower than the design
elevation.
Page 5
Basin & Swales Inspection and Maintenance Checklist Date of Inspection: _______ _
Property Address: __________ _ Treatment Measure No.: --------
Defect Conditions When Maintenance Comments (Describe maintenance Results Expected When Maintenance Is Performed
Maintenance Is Needed Needed? (Y/N) completed and if any needed maintenance was
not conducted, note when it will be done.)
Tree Growth Tree growth on berms or • Trees should be removed. If root system is small
emergency spillway >4 ft in (base less than 4 inches) the root system may be
height or covering more than left in place. Otherwise the roots should be
10% of spillway. removed and the berm restored.
• A civil engineer should be consulted for proper
berm/spillway restoration.
Emergency Rock is missing and soil is Rocks and pad depth are restored to design standards.
Overflow/ exposed at top of spillway or
Spillway outside slope.
Debris Barriers (e.g., Trash Racks)
Trash and Trash or debris is plugging Trash or debris is removed and disposed of properly.
Debris openings in the barrier.
Damaged/ Bars are missing, loose, bent Bars are repaired or replaced to allow proper
Missing Bars out of shape, or deteriorating functioning of trash rack.
due to excessive rust.
Inlet/Outlet Debris barrier is missing or Debris barrier is repaired or replaced to allow proper
Pipe not attached to pipe. functioning of trash rack.
Fencing and Gates
Missing or Any defect in or damage to Fencing and gate are restored to design specifications.
broken parts the fence or gate that
permits easy entry to a
facility.
Deteriorating Part or parts that have a Paint or protective coating is sufficient to protect
Paint or rusting or scaling condition structural adequacy of fence or gate.
Protective that has affected structural
Coating adequacy.
Flow Duration Control Outlet (if included in design to meet Hydromodification Management Standard)
Risers, orifices Any debris or clogging Restore unobstructed flow through discharge structure;
and screens to meet original design; dispose of debris properly.
Drawdown Noticeable ponding Restore infiltration and ponded waters permeate.
time exceeding 72-hours after a Scarification should only be performed when there are
design storm event signs of clogging rather than on a routine basis. Always
remove deposited sediments before scarification and
use a hand-guided rotary tiller.
Swales (in addition to general items listed above)
Page 6
Basin & Swales Inspection and Maintenance Checklist Date of Inspection: _______ _
Property Address: __________ _ Treatment Measure No.: _______ _
Defect Conditions When Maintenance Comments (Describe maintenance Results Expected When Maintenance Is Performed
Maintenance Is Needed Needed? (Y/N) completed and if any needed maintenance was
not conducted, note when it will be done.)
Impeded Flow Twice annually at beginning Trash and debris cleared from swale and disposed of
and end of wet season. After properly especially prior to mowing.
heavy runoff. Visible
blockage or impediments.
Landscaping Twice annually at beginning Maintained flow and healthy vegetation.
or Vegetative and end of wet season or as
Overgrowth needed for aesthetics.
Miscellaneous
Miscellaneous Any condition not covered Meets the design specifications.
above that needs attention
to restore infiltration basin to
design conditions.
Page 7
BMP MAINTENANCE FACT SHEET
FOR
STRUCTURAL BMP BF-1 BIOFILTRATION
BF-1
Biofiltration
Biofiltration facilities are vegetated surface water systems that filter water through vegetation, and soil or
engineered media prior to discharge via underdrain or overflow to the downstream conveyance system.
Biofiltration facilities have limited or no infiltration. They are typically designed to provide enough hydraulic head
to move flows through the underdrain connection to the storm drain system. Typical biofiltration components
include:
• Inflow distribution mechanisms (e.g., perimeter flow spreader or filter strips)
• Energy dissipation mechanism for concentrated inflows (e.g., sp lash blocks or riprap)
• Shallow surface ponding for captured flows
• Side slope and basin bottom vegetation selected based on climate and ponding depth
• Non-floating mulch layer
• Media layer (planting mix or engineered media) capable of supporting vegetation growth
• Filter course layer cons isting of aggregate to prevent the migration of fines into uncompacted native soils
or the aggregate storage layer
• Aggregate storage layer with underdrain(s)
• Impermeable liner or uncompacted native soils at the bottom of the facility
• Overflow structure
Normal Expected Maintenance
Biofiltration requires routine maintenance to: remove accumulated materials such as sediment, trash or debris;
maintain vegetation health; maintain infiltration capacity of the media layer; replenish mulch; and maintain
integrity of side slopes, inlets, energy dissipators, and outlets. A summary table of standard inspection and
maintenance indicators is provided within this Fact Sheet.
Non-Standard Maintenance or BMP Failure
If any of the following scenarios are observed, the BMP is not performing as intended to protect downstream
waterways from pollution and/or erosion . Corrective maintenance, increased inspection and maintenance, BMP
replacement, or a different BMP type will be required.
• The BMP is not drained between storm events. Surface ponding longer than approximately 24 hours
following a storm event may be detrimental to vegetation health, and surface ponding longer than
approximately 96 hours following a storm event poses a risk of vector (mosquito) breeding. Poor drainage
can result from clogging of the media layer, filter course, aggregate storage layer, underdrain, or outlet
structure. The specific cause of the drainage issue must be determined and corrected.
• Sediment, trash, or debris accumulation greater than 25% of the surface ponding volume within one
month. This means the load from the tributary drainage area is too high, reducing BMP function or
clogging the BMP. This would require pretreatment measures within the tributary area draining to the
BMP to intercept the materials. Pretreatment components, especially for sediment, will extend the life of
components that are more expensive to replace such as media, filter course, and aggregate layers.
• Erosion due to concentrated storm water runoff flow that is not readily corrected by adding erosion
control blankets, adding stone at flow entry points, or minor re-grading to restore proper drainage
according to the original plan. If the issue is not corrected by restoring the BMP to the original plan and
grade, the [City Engineer) shall be contacted prior to any additional repairs or reconstruction.
BF-1 Page 1 of 11
January 12, 2017
Other Special Considerations
BF-1
Biofiltration
Biofiltration is a vegetated structural BMP . Vegetated structural BMPs that are constructed in the vicinity of, or
connected to, an existing jurisdictional water or wetland could inadvertently result in creation of expanded waters
or wetlands. As such, vegetated structural BMPs have the potential to come under the jurisdiction of the United
States Army Corps of Engineers, SDRWQCB, California Department of Fish and Wildlife, or the United States Fish
and Wildlife Service. This could result in the need for specific resource agency permits and costly mitigation to
perform maintenance of the structural BMP. Along with proper placement of a structural BMP, routine
maintenance is key to preventing this scenario.
BF-1 Page 2 of 11
January 12, 2017
BF-1
Biofiltration
SUMMARY OF STANDARD INSPECTION AND MAINTENANCE FOR BF-1 BIOFILTRATION
The property owner is responsible to ensure inspection, operation and maintenance of permanent BMPs on their property unless responsibility has been formally transferred to
an agency, community facilities district, homeowners association, property owners association, or other special district.
Maintenance frequencies listed in this table are average/typical frequencies. Actual maintenance needs are site-specific, and maintenance may be required more frequently.
Maintenance must be performed whenever needed, based on maintenance indicators presented in this table. The BMP owner is responsible for conducting regular inspections
to see when maintenance is needed based on the maintenance indicators. During the first year of operation of a structural BMP, inspection is recommended at least once prior
to August 31 and then monthly from September through May. Inspection during a storm event is also recommended. After the initial period of frequent inspections, the
minimum inspection and maintenance frequency can be determined based on the results of the first year inspections.
Th res hold/In di ca tor Maintenance Action Typical Maintenance Frequency
Accumulation of sediment, litter, or debris Remove and properly dispose of accumulated materials, • Inspect monthly. If the BMP is 25% full* or more in
without damage to the vegetation or compaction of the one month, increase inspection frequency to monthly
media layer. plus after every 0.1-inch or larger storm event.
• Remove any accumulated materials found at each
inspection.
Obstructed inlet or outlet structure Clear blockage. • Inspect monthly and after every 0.5-inch or larger
storm event.
• Remove any accumulated materials found at each
inspection.
Damage to structural components such as weirs, inlet or Repair or replace as applicable • Inspect annually.
outlet structures • Maintenance when needed.
Poor vegetation establishment Re-seed, re-plant, or re-establish vegetation per original • Inspect monthly.
plans. • Maintenance when needed.
Dead or diseased vegetation Remove dead or diseased vegetation, re-seed, re-plant, • Inspect monthly.
or re-establish vegetation per original plans. • Maintenance when needed.
Overgrown vegetation Mow or trim as appropriate. • Inspect monthly.
• Maintenance when needed.
2/3 of mulch has decomposed, or mulch has been Remove decomposed fraction and top off with fresh • Inspect monthly.
removed mulch to a total depth of 3 inches. • Replenish mulch annually, or more frequently when
needed based on inspection.
*"25% full" is defined as¼ of the depth from the design bottom elevation to the crest of the outflow structure (e .g., if the height to the outflow opening is 12 inches from the
bottom elevation, then the materials must be removed when there is 3 inches of accumulation -this should be marked on the outflow structure).
BF-1 Page 3 of 11
January 12, 2017
BF-1
Biofiltration
SUMMARY OF STANDARD INSPECTION AND MAINTENANCE FOR BF-1 BIOFILTRATION (Continued from previous page)
Threshold/Indicator
Erosion due to concentrated irrigation flow
Erosion due to concentrated storm water runoff flow
Standing water in BMP for longer than 24 hours
following a storm event
Surface ponding longer than approximately 24 hours
following a storm event may be detrimental to
vegetation health
Presence of mosquitos/larvae
For images of egg rafts, larva, pupa, and adult
mosquitos, see
httr:1 :LLwww.mosguito.orgLbiologll
Underdrain clogged
Maintenance Action
Repair/re-seed/re-plant eroded areas and adjust the
irrigation system.
Repair/re-seed/re-plant eroded areas, and make
appropriate corrective measures such as adding erosion
control blankets, adding stone at flow entry points, or
minor re-grading to restore proper drainage according
to the original plan. If the issue is not corrected by
restoring the BMP to the original plan and grade, the
[City Engineer] shall be contacted prior to any additional
repairs or reconstruction.
Make appropriate corrective measures such as adjusting
irrigation system, removing obstructions of debris or
invasive vegetation, clearing underdrains, or
repairing/replacing clogged or compacted soils.
If mosquitos/larvae are observed: first, immediately
remove any standing water by dispersing to nearby
landscaping; second, make corrective measures as
applicable to restore BMP drainage to prevent standing
water.
If mosquitos persist following corrective measures to
remove standing water, or if the BMP design does not
meet the 96-hour drawdown criteria due to release
rates controlled by an orifice installed on the
underdrain, the [City Engineer] shall be contacted to
determine a solution. A different BMP type, or a Vector
Management Plan prepared with concurrence from the
County of San Diego Department of Environmental
Hea lth, may be required.
Clear blockage.
BF-1 Page 4 of 11
January 12, 2017
Typical Maintenance Frequency
• Inspect monthly.
• Maintenance when needed.
• Inspect after every 0.5-inch or larger storm event. If
erosion due to storm water flow has been observed,
increase inspection frequency to after every 0.1-inch
or larger storm event.
• Maintenance when needed. If the issue is not
corrected by restoring the BMP to the original plan
and grade, the [City Engineer] shall be contacted prior
to any additional repairs or reconstruction.
• Inspect monthly and after every 0.5-inch or larger
storm event. If standing water is observed, increase
inspection frequency to after every 0.1-inch or larger
storm event.
• Maintenance when needed.
• Inspect monthly and after every 0.5-inch or larger
storm event. If mosquitos are observed, increase
inspection frequency to after every 0.1-inch or larger
storm event.
• Maintenance when needed.
• Inspect if standing water is observed for longer than
24-96 hours following a storm event.
• Maintenance when needed.
References
American Mosquito Control Association.
http://www.mosquito.org/
California Storm Water Quality Association {CASQA). 2003. Municipal BMP Handbook.
https://www .casqa.org/resou rces/bm p-ha nd books/mu nici pa I-bm p-ha nd book
County of San Diego. 2014. Low Impact Development Handbook.
http://www.sandiegocounty.gov/content/sdc/dpw/watersheds/susmp/lid.html
San Diego County Copermittees. 2016. Model BMP Design Manual, Appendix E, Fact Sheet BF-1.
http://www.projectcleanwater.org/index.php?option=com content&view=article&id=250&Itemid=220
BF-1 Page 5 of 11
January 12, 2017
BF-1
Biofiltration
Page Intentionally Blank for Double-Sided Printing
BF-1 Page 6 of 11
January 12, 2017
BF-1
Biofiltration
Date:
Permit No.:
Property/ Development Name:
Property Address of BMP:
Threshold/Indicator
Accumulation of sediment, litter, or debris
Maintenance Needed?
0 YES
□ NO
□ N/A
Poor vegetation establishment
Maintenance Needed?
0 YES
0 NO
□ N/A
I Inspector: I BMP ID No.:
I APN(s):
Responsible Party Name and Phone Number:
Responsible Party Address:
INSPECTION AND MAINTENANCE CHECKLIST FOR BF-1 BIOFILTRATION PAGE 1 of 5
BF-1
Biofiltration
Maintenance Recommendation Date Description of Maintenance Conducted
D Remove and properly dispose of
accumulated materials, without damage
to the vegetation
D If sediment, litter, or debris accumulation
exceeds 25% of the surface ponding
volume within one month (25% full*},
add a forebay or other pre-treatment
measures within the tributary area
draining to the BMP to intercept the
materials.
D Other/ Comments:
D Re-seed, re-plant, or re-establish
vegetation per original plans
D Other/ Comments:
*"25% full" is defined as ¼ of the depth from the design bottom elevation to the crest of the outflow structure (e.g., if the height to the outflow opening is 12 inches from the
bottom elevation, then the materials must be removed when there is 3 inches of accumulation -this should be marked on the outflow structure).
BF-1 Page 7 of 11
January 12, 2017
Date: Inspector:
Permit No.: APN{s):
BMP ID No.:
BF-1
Biofiltration
INSPECTION AND MAINTENANCE CHECKLIST FOR BF-1 BIOFILTRATION PAGE 2 of 5
Threshold/Indicator
Dead or diseased vegetation
Maintenance Needed?
0 YES
0 NO
□ N/A
Overgrown vegetation
Maintenance Needed?
0 YES
0 NO
0 N/A
2/3 of mulch has decomposed, or mulch has
been removed
Maintenance Needed?
0 YES
0 NO
0 N/A
Maintenance Recommendation
0 Remove dead or diseased vegetation, re-
seed, re-plant, or re-establish vegetation
per original plans
D Other/ Comments:
D Mow or trim as appropriate
D Other/ Comments:
0 Remove decomposed fraction and top off
with fresh mulch to a total depth of 3
inches
D Other/ Comments:
BF-1 Page 8 of 11
January 12, 2017
Date Description of Maintenance Conducted
Date: Inspector:
Permit No.: APN(s):
BMP ID No.:
BF-1
Biofiltration
INSPECTION AND MAINTENANCE CHECKLIST FOR BF-1 BIOFILTRATION PAGE 3 of S
Threshold/Indicator
Erosion due to concentrated irrigation flow
Maintenance Needed?
□ YES
□ NO
□ N/A
Erosion due to concentrated storm water runoff
flow
Maintenance Needed?
□ YES
□ NO
□ N/A
Maintenance Recommendation
D Repair/re-seed/re-plant eroded areas and
adjust the irrigation system
D Other/ Comments:
D Repair/re-seed/re-plant eroded areas,
and make appropriate corrective
measures such as adding erosion
control blankets, adding stone at flow
entry points, or minor re-grading to
restore proper drainage according to
the original plan
D If the issue is not corrected by restoring
the BMP to the original plan and grade,
the [City Engineer] shall be contacted
prior to any additional repairs or
reconstruction
D Other/ Comments:
BF-1 Page 9 of 11
January 12, 2017
Date Description of Maintenance Conducted
Date: Inspector:
Permit No.: APN(s):
BMP ID No.:
BF-1
Biofiltration
INSPECTION AND MAINTENANCE CHECKLIST FOR BF-1 BIOFILTRATION PAGE 4 of S
Threshold/Indicator
Obstructed inlet or outlet structure
Maintenance Needed?
0 YES
□ NO
0 N/A
Underdrain clogged (inspect underdrain if
standing water is observed for longer than 24-96
hours following a storm event)
Maintenance Needed?
0 YES
□ NO
0 N/A
Damage to structural components such as weirs,
inlet or outlet structures
Maintenance Needed?
□YES
0 NO
0 N/A
Maintenance Recommendation
D Clear blockage
D Other/ Comments:
D Clear blockage
D Other/ Comments:
D Repair or replace as applicable
D Other/ Comments:
BF-1 Page 10 of 11
January 12, 2017
Date Description of Maintenance Conducted
Date: Inspector:
Permit No.: APN(s}:
BMP ID No.:
BF-1
Biofiltration
INSPECTION AND MAINTENANCE CHECKLIST FOR BF-1 BIOFILTRATION PAGES of 5
Threshold/Indicator
Standing water in BM P for longer than 24-96
hours following a storm event•
Surface ponding longer than approximately 24
hours following a storm event may be
detrimental to vegetation health
Maintenance Needed?
□ YES
□ NO
□ N/A
Presence of mesquites/larvae
For images of egg rafts, larva, pupa, and adult
mesquites, see
http://www.mosquito.org/biology
Maintenance Needed?
□ YES
□ NO
□ N/A
Maintenance Recommendation
D Make appropriate corrective measures
such as adjusting irrigation system,
removing obstructions of debris or
invasive vegetation, clearing
underdrains, or repairing/replacing
clogged or compacted soils
D Other/ Comments:
D Apply corrective measures to remove
standing water in BMP when standing
water occurs for longer than 24-96
hours following a storm event.••
D Other/ Comments:
Date Description of Maintenance Conducted
*Surface ponding longer than approximately 24 hours following a storm event may be detrimental to vegetation health, and surface ponding longer than approximately 96 hours
following a storm event poses a risk of vector (mosquito} breeding. Poor dra inage can result from clogging of the media layer, filter course, aggregate storage layer, underdrain,
or outlet structure. The specific cause of the drainage issue must be determined and corrected.
**If mesquites persist following corrective measures to remove standing water, or if the BMP design does not meet the 96-hour drawdown criteria due to release rates
controlled by an orifice installed on the underdrain, the [City Engineer] shall be contacted to determine a solution. A different BMP type, or a Vector Management Plan prepared
with concurrence from the County of San Diego Department of Environmental Health, may be required.
BF-1 Page 11 of 11
January 12, 2017
Attachment 4
City Standard Single Sheet
BMP (SSBMP) Exhibit
Page intentionally blank
BLANK PAGE
I
~'¼-d,
Cl
[
S;
-,-
20 0 20
'
40
./
/ /--w-,, -
6" MIN. FREEBOARD 6" MIN. FREEBOARD
i-----------5.00'-----------l
24"X24" OVERFLOW
RISER
12" WATER SURFACE
RIPRAP PER PLAN
148.75FG
3 1 /8" MIN. lHICKNESS
PAVERS W/ MIN. 3/8" VOID
BEDDING COURSE -1.5"
lHICK OF 1 /8" TO 3 /8"
(N0.8) AGGREGATE
6" QASS 2 AGGREGATE
PIPE AT 1"
ABOVE SUBGRADE
•
VOID FILLER -1 /8" TO 3/8" (NO. 8)
AGGREGATE IN VOIDS
4.5"
;,
1--"c..;•.i 0.5'
CONCRETE FOOTING
MIN. 12• IN SUBGRADE
__,---, 3" PERFORATED PIPE
SCH 40, PVC
SOIL SUBGRADE
-
~1 <
I "
BMP ID#
I
I
I
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.. _E
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BMPTYPE SYMBOL
TREATMENT CONTROL
BIOFIL TRA TION1 + + + + + + ♦ + +
PARTY RESPONSIBLE FOR MAINTENANCE:
NAME _ ___..M~AG~N~O~Ll~A~""'-'L~L~C __
ADDRESS 5 HOYA STREET CONTACT BEN RYAN
RANCHO MISSION VIEJO CA ---'"='-'-.W..C"-'---
PHONE NO. /858) 794-1900
PLAN PREPARED BY:
NAME_---"D'--'AVl,,,D"-'C"'-AR"-=ONc,___ __ _
COMPANY CIVIL LANDWORKS CORP.
ADDRESS 110 COPPERWOOD WAY, SUITE P
OCEANSIDE CA 92058
PHONE NO. 1760) 91&87 45
BMPNOTES: CERTIFICATION ____ _
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 CllY ENGINEER.
3. NO SUBSTITUTIONS TO THE MATERIAL OR TYPES OR PLANTING lYPES
WITHOUT PRIOR APPROVAL FROM THE CllY ENGINEER.
4. NO OCCUPANCY WILL BE GRANTED UNTIL TH E CllY INSPECTION STAFF
HAS INSPECTED THIS PROJECT FOR APPROPRIATE BMP CONSTRUCTION
AND INSTALLATION.
5. REFER TO MAINTENANCE AGREEMENT DOCUMENT.
6. SEE PROJECT SWMP FOR ADDITIONAL INFORMATION.
CONSTRUCTION NOTES:
G) CONSTRUCT BIOFILTRAllON BASIN PER DETAIL 1 SHEET 3 OF DWG. 515-3A
(I} INSTALL PERMEABLE PAVERS PER DETAIL SHEET 6 OF DWG. 515-3A
@ INSTALL BMP SIGN & DETAIL PER lHIS SHEET
PERMANENT WATER QUALITY
TREATMENT FACILITY
KEEPING OUR WATER WAYS a.EAN
MAINTAIN l'fllH CARE -NO MODIFICATIONS l'fllHOUT AGENCY APPROVAL
DETAIL
WATER QUALITY SIGN PLACED
CASQA NO.
TC-32
EACH BIOFIL TRATION BASIN
NOTE: All BIOFIL TRA TION AREAS 'Mll
HA VE A SIGN POSTED TO BE
VISIBLE AT ALL TIMES.
BMP TABLE
QUANTllY DRAWING NO. SHEET NO.(S)
1,150 SF. 515-3A 2
INSPECTION *
FREQUENCY
AT
MAINTENANCE *
FREQUENCY
GRAPHIC SCALE
SCALE: 1"= 20'
147.30FG
148.30TG PERMEABLE PAVERS DETAIL OR EQUIVALENT
N. T.S.
(!)
0
AREA + + + +
PERVIOUS Ell PAVEMENT
QUARTERLY SEMI-ANNUALLY
TC-10 6,507 SF. 515-3A 4, 5 SEMI-ANNUALLY ANNUALLY
IMPERMEABLE LINER*
MIRAA 140N OR EQUIV.
TERRA TEXN0.3 FILTER
BLANKET
T = 2 BLANKETS
1: 1 EXCAVATED
Civil Dandworks
SLOPE -
MIN. 18" MEDIA **1'11~ I
MIN. 5 IN/HR
FILTRATION RA TE
3" OF 3 /8" GRAVEL
UNDER PERFORATED
PIPE
6" PERFORATED
PIPE
EXISTING
UNCOMPACTED SOILS
ORIFICE PLATE
( 4.6" ORIFICE)
SEE DETAIL RIGHT
*IMPERMEABLE LINER TO BE PLACED ALONG lHE SIDES OF lHE BIORETENllON BASIN
IMPERMEABLE LINER*
MIRAFl 140N OR EQUIV.
10" TOTAL OF 3/8" GRAVEL
PERVIOUS MICROFILTER FABRIC AROUND
GRAVEL MIRAA 140N "FIL TRA llON" OR
EQUIVALENT
12" SD OUTLET
144.97IE
**BIORETENTION 'ENGINEERED SOIL"LAYER SHALL BE MINIMUM 18"DEEP 'SANDY LOAM"SOIL MIX l'fllH NO MORE lHAN 5%
CLAY CONTENT. lHE MIX SHALL CONTAIN 50-60% SAND, 20-30% COMPOST OR HARDWOOD MULCH, AND 20-30%
TOPSOIL
ORIFICE PLATE: MIN SQUARE
DIMENSIONS 1.0 FT. GREATER
lHAN PIPE DIA. HOT-DIP
GALVANIZED PLATE AFTER
HOLES HA VE BEEN DRILi.ED
MIN. 6"
INFLOW PIPE j_
.--+---'-----'---::io t
0
tlQlE:.
1. ORIFICE PLATE & FLANGE CONNECTION
TO CONCRETE SHALL BE FITTED l'fllH 30
DUROMETER NEOPRENE RING.
2 MAINTENANCE ACCESS FROM 24"X24"
RISER.
3. CLEARING OF ORIFICE TO BE CLEANED
\\llH WATER JET OR EQUIVALENT
MElHODS
ORIFICE 4.6" DIAMETER (DIA)
DETAIL 1: BIOFIL TRA TlON WITH
"' WAIL > 110 COPPERWOOD WAY, SUITE P, OCEANSIDE, CA 92058 PARTlAL RETENTlON BASIN FLOW CONJR(l. CffiCE PLAJE
Q) BMPSIGN -,:,-6 EA. 515-3A 3,4,5 SEMI-ANNUALLY ANNUALLY
fSHEETj CITY OF CARLSBAD I SHE1ETS I
~====~~====t================================t=====1====jt====1====j ~ ENGINEERING DEPARTh1ENT
l-----t--+-----------------11------+--+----I---I SINGLE SHEET BMP SITE PLAN
DA 1E INITIAL DAlE INITIAL
ENGINEER OF WORK REVISION DESCRIPTION OlliER APPROVAL
DA 1E INITIAL
CITY APPROVAL
MAGNOLIA
GR2019-0021
GR2018-0047
RECORD COPY
INITIAL DATE
BRADY
PROJECT NO.
DRAWING NO.
~ PH: 760-908-8745 • info@civillandworks.com NTS NTS _________________________________________ .,:;_iiiiiiiiiiiiii..:.;;;iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii.;._iiiiiiiiiiiiii~iiiiiiiiiiiiii~iiiiiiiiiiiiii~~~~~~~~