HomeMy WebLinkAboutHDP 2020-0001; COLLEGE BOULEVARD MITIGATION; PRELIMINARY STORM WATER QUALITY MANAGEMENT PLAN; 2019-10-31CITY OF CARLSBAD
STANDARD PROJECT
PRELIMINARY STORM WATER QUALITY MANAGEMENT PLAN (SWQMP)
FOR CEQA PURPOSES
RAYMOND L. MARTIN
ENGINEER OF WORK
COLLEGE BLVD HABITAT MITIGATION PLAN
[PROJECT ID]
[DRAWING No. (DWG _-_)]
ENGINEER OF WORK:
48670 6/30/20 10/31/2019
RCE EXP.UC.DATE DATE
PREPARED FOR:
WEST DEVELOPMENT
5800 Armada Drive, Suite 100
Carlsbad, CA 92008
(760)602-5827
PREPARED BY:
HUNSAKER & ASSOCIATES
San Diego, Inc.
9707 WAPLES STREET
San Diego, CA 92121
PH(858)558-4500 FX(858)558-1414
DATE:
10/31/2019
R•~::~ JVED
FEB 1 ! 2020
CITY OF CAR!...SBAD
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TABLE OF CONTENTS
Certification Page
Project Vicinity Map
FORM E-34 Storm Water Standard Questionnaire
FORM E-36 Standard Project Requirement Checklist
Attachment 1: OMA Exhibit
Attachment 2: Hydrologic Soil Group
0
CERTIFICATION PAGE
Project Name: College Blvd Habitat Mitigation Plan
Project ID:
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.
ff.c.E #: 48670, EXP.UC.DATE: 6/30/20
Engi · o Work's Signature, PE Number & Expiration Date
RAYMOND L. MARTIN
Print Name
HUNSAKER & ASSOCIATES San Diego, Inc
Company
10/24/2019
Date
C
PROJECT VICINITY MAP
PROJECT
SITE
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VICINITY MAP
NOT TO SCALE
C_cicyof
Carlsbad
STORM WATER STANDARDS
QUESTIONNAIRE
Development Services
Land Development Engineering
1635 Faraday Avenue
(760) 602-2750
www.carlsbadca.gov
E-34
j 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: College Blvd Habitat Mitigation Plan PROJECT ID:
ADDRESS: APN : 209-060-71 & 209-060-72
The project is (check one): D New Development 00 Redevelopment
The total proposed disturbed area is: 374616 ft2 ( 8.6 ) acres
The total proposed newly created and/or replaced impervious area is: 0 ft2 ( 0 ) 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 03/19
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 □ IX] 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.
STEP2
TO BE COMPLETED FOR ALL DEVELOPMENT PROJECTS
To determine if your project is exempt from PDP requirements pursuant to MS4 Permit Provision E.3.b.(3), please answer
the following questions:
Is your project LIMITED to one or more of the following :
YES NO
1. Constructing new or retrofitting paved sidewalks, bicycle lanes or trails that meet the following criteria:
a) Designed and constructed to direct storm water runoff to adjacent vegetated areas, or other non-
erodible permeable areas; OR □ IX] b) Designed and constructed to be hydraulically disconnected from paved streets or roads; OR
c) Designed and constructed with permeable pavements or surfaces in accordance with USEPA
Green Streets guidance?
2. Retrofitting or redeveloping existing paved alleys, streets, or roads that are designed and constructed in □ IX] 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? □ IX]
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 REV 03/19
STEP3
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, □ [XI
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 □ 00 more of impervious surface? This includes commercial, industrial, residential, mixed-use, and public
development projects on public or private land.
3. Is your project a new or redevelopment project that creates and/or replaces 5,000 square feet or more
of impervious surface collectively over the entire project site and supports a restaurant? A restaurant is
a facility that sells prepared foods and drinks for consumption, including stationary lunch counters and □ [Z]
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 □ 00
development proiect 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 parking lot? A parking lot is □ [XI a land area or facility for the temporary parking or storage of motor vehicles used personally for
business or for commerce.
6. Is your project a new or redevelopment project that creates and/or replaces 5,000 square feet or more
of impervious street, road, highway, freeway or driveway surface collectively over the entire project □ 00 site? A street, road, highway, freeway or driveway is any paved impervious surface used for the
transportation of automobiles, trucks, motorcycles, and other vehicles.
7. Is your project a new or redevelopment project that creates and/or replaces 2,500 square feet or more
of impervious surface collectively over the entire site, and discharges directly to an Environmentally
Sensitive Area (ESA)? "Discharging Directly to" includes flow that is conveyed overland a distance of □ [XI
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 comminaled with flows from adjacent lands).*
8. Is your project a new development or redevelopment project that creates and/or replaces 5,000 square
feet or more of impervious surface that supports an automotive repair shop? An automotive repair □ [XI 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 □ 00 RGO's that meet the following criteria: (a) 5,000 square feet or more or (b) a project Average Daily
Traffic (ADT) of 100 or more vehicles per day.
10. Is your project a new or redevelopment project that results in the disturbance of one or more acres of land □ IX] and are expected to generate pollutants post construction?
11 . Is your project located within 200 feet of the Pacific Ocean and (1) creates 2,500 square feet or more of
impervious surface or (2) increases impervious surface on the property by more than 10%? (CMC □ [X]
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 aoolicant information.
E-34 Page 3 of 4 REV 03/19
STEP4
TO BE COMPLETED FOR REDEVELOPMENT PROJECTS THAT ARE PRIORITY DEVELOPMENT PROJECTS (PDP)
ONLY
Complete the questions below regarding your redevelopment project (MS4 Permit Provision E.3.b.(2)):
YES NO
Does the redevelopment project result in the creation or replacement of impervious surface in an amount
of less than 50% of the surface area of the previously existing development? Complete the percent
impervious calculation below:
Existing impervious area (A) = sq . ft. □ Ix]
Total proposed newly created or replaced impervious area (8) = sq. ft.
Percent impervious area created or replaced (B/A)*100 = %
If you answered "yes", the structural BMPs required for PDP apply only to the creation or replacement of impervious
surface and not the entire development. Go to step 5, check the first box stating "My project is a PDP ... " and complete
applicant information.
If you answered "no," the structural BM P's required for PDP apply to the entire development. Go to step 5, check the
check the first box statinq "Mv project is a PDP ... "and complete aoolicant information.
STEPS
CHECK THE APPROPRIATE BOX AND COMPLETE APPLICANT INFORMATION
D My project is a PDP and must comply with PDP stormwater requirements of the BMP Manual. I understand I must
prepare a Storm Water Quality Management Plan (SWQMP) for submittal at time of application.
Ix] My project is a 'STANDARD PROJECT' OR EXEMPT from PDP and must only comply with 'STANDARD PROJECT'
stormwater requirements of the BMP Manual. As part of these requirements, I will submit a "Standard Project
Requirement Checklist Form E-36" and incorporate low impact development strategies throughout my project.
Note: For projects that are close to meeting the PDP threshold, staff may require detailed impervious area calculations
and exhibits to verify if 'STANDARD PROJECT' stormwater requirements apply.
D My Project is NOT a 'development project' and is not subject to the requirements of the BMP Manual.
Applicant Information and Signature Box
Applicant Name: Kurt K. Wickham Applicant Title:
Applicant Signature: Date:
.. .. • Environmentally Sensitive Areas include but are not limited to all Clean Water Act Section 303(d) 1mpa1red water bodies; areas designated as Areas of Special
Biological Significance by the State Water Resources Control Board (Water Quality Control Plan for the San Diego Basin (1994) and amendments); water bodies
designated with the RARE beneficial use by the State Water Resources Control Board (Water Quality Control Plan for the San Diego Basin (1994) and
amendments); areas designated as preserves or their equivalent under the Multi Species Conservation Program within the Cities and County of San Diego; Habitat
Management Plan; and any other equivalent environmentally sensitive areas which have been identified by the City.
This Box for Citv Use Onlv
YES NO
City Concurrence: □ □
By:
Date:
Project ID:
E-34 Page 4 of 4 REV 03/19
C cicyof
Carlsbad
STANDARD PROJECT
REQUIREMENT
CHECKLIST
E-36
Project Information
Project Name: College Blvd Habitat Mitigation Plan
Project ID:
DWG No. or Building Permit No.:
Source Control BMPs
Development Services
Land Development Engineering
1635 Faraday Avenue
(760) 602-2750
www.carlsbadca.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 (Volume 5 of City Engineering Standards) 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 Illicit Discharges into the MS4 □Yes □ No Iii N/A
Discussion/justification if SC-1 not implemented:
Project creates a wetland areas for habitat mitigation, has no impervious areas and does not
discharge any pollutants.
SC-2 Storm Drain Stenciling or Signage □Yes □ No Iii N/A
Discussion/justification if SC-2 not implemented:
Project creates a wetland areas for habitat mitigation and does not include any storm drains or inlets
for stenciling/signage.
SC-3 Protect Outdoor Materials Storage Areas from Rainfall, Run-On, Runoff, and Wind □Yes O No Iii N/A Dispersal
Discussion/justification if SC-3 not implemented:
E-36 Page 1 of 4 Revised 09/16
Source Control Reaulrement (continued) Applied?
SC-4 Protect Materials Stored in Outdoor Work Areas from Rainfall, Run-On, Runoff, and □Yes □ No lil NIA Wind Dispersal
Discussion/justification if SC-4 not implemented:
SC-5 Protect Trash Storage Areas from Rainfall, Run-On, Runoff, and Wind Dispersal □Yes □ No Iii N/A
Discussion/justification if SC-5 not implemented:
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 Quidance).
□ On-site storm drain inlets □Yes □ No lil N/A
□ Interior floor drains and elevator shaft sump pumps □Yes □ No lil N/A
□ Interior parking garages □Yes □ No lil N/A
□ Need for future indoor & structural pest control □Yes D No lil N/A
□ Landscape/Outdoor Pesticide Use □Yes D No lil N/A
□ Pools, spas, ponds, decorative fountains, and other water features □Yes □ No Iii N/A
□ Food service □Yes D No Iii N/A
□ Refuse areas □Yes □ No Iii N/A
□ Industrial processes □Yes □ No Iii N/A
□ Outdoor storage of equipment or materials □Yes □ No Iii N/A
□ Vehicle and Equipment Cleaning □Yes □ No Iii N/A
□ Vehicle/Equipment Repair and Maintenance □Yes D No lil N/A
□ Fuel Dispensing Areas □Yes □ No Iii N/A
□ Loading Docks □Yes 0 No Ii] N/A
□ Fire Sprinkler Test Water □Yes □ No Iii N/A
□ Miscellaneous Drain or Wash Water □Yes D No Iii N/A
□ Plazas, sidewalks, and parking lots □Yes □ No lil NIA
For "Yes" answers, identify the additional BMP per Appendix E.1. Provide justification for "No" answers.
E-36 Page 2 of 4 Revised 09/16
(=) -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 (Volume 5 of City Engineering Standards) 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.
Site Design Requirement I Applied?
SD-1 Maintain Natural Drainage Pathways and Hydrologic Features I □Yes I □ No I Iii N/A
Discussion/justification if SD-1 not implemented:
SELF-MIGIGATING AREA -NOT REQUIRED
SD-2 Conserve Natural Areas, Soils, and Vegetation I □Yes I □ No I Iii NIA
Discussion/justification if SD-2 not implemented:
SELF-MIGIGATING AREA -NOT REQUIRED
SD-3 Minimize Impervious Area I □Yes I □ No I ~ NIA
Discussion/justification if SD-3 not implemented:
SELF-MIGIGATING AREA -NOT REQUIRED
SD-4 Minimize Soil Compaction I □Yes I □ No I Iii NIA
Discussion/justification if SD-4 not implemented:
SELF-MIGIGATING AREA -NOT REQUIRED
SD-5 Impervious Area Dispersion I □Yes I □ No I Iii N/A
Discussion/justification if SD-5 not implemented:
SELF-MIGIGATING AREA-NOT REQUIRED
E-36 Page 3 of 4 Revised 09/16
Site Design Requirement (continued) I Applied?
SD-6 Runoff Collection I □Yes I □ No I Iii N/A
Discussion/justification if SD-6 not implemented:
SELF-MIGIGATING AREA -NOT REQUIRED
SD-7 Landscaping with Native or Drought Tolerant Species I □Yes I □ No I Iii N/A
Discussion/justification if SD-7 not implemented:
SELF-MIGIGATING AREA-NOT REQUIRED
SD-8 Harvesting and Using Precipitation I □Yes I □ No I Iii NIA
Discussion/justification if SD-8 not implemented:
SELF-MIGIGATING AREA-NOT REQUIRED
E-36 Page 4 of 4 Revised 09/16
ATTACHMENT 1
OMA EXHIBIT
RIP RAP SLOPE
PROTECTION
LEGEND
-··--------------
DMAX
Ill
I
I
I
PROJECT BOUNDARY
OMA BOUNDARY
PROPOSED BUFFER
L/MfTS OF WETLAND CREA noN
OMA/0 -·· OMA AREAS (SELF-MmGA nNG)
I ( -----/ _ ... 7 \ .. _::::: _) : --------
~PARCEL A ~
) ♦ /_/
♦
IOOYEARF}._~ _-,.•
P~N / c.O~
(P~OJECT) ~
~1:H~~JT
.. Tl<lATIOH PROJECT)
COUEGE !II.VO.
810oRETamoHIIASIN
(NOT A PART OF HASrfAT
.. TIQATIOH PROJECT)
PARCEL 8
(0.84 AC)
---"/'-----
EXIST SEWER LATERAL 1 ~
TO ee REMOVED CONSTRUCT----------
'--100 YEAR FLOOD PLAIN
(POST-PROJECT)
SEWER COOR f
MANHOLE ON
EXISTING MAIN
··---•■---·· ··-----• • ---r-100 YEAR FLOOD PLAIN
--------
(PRE-PROJECT") ----~
/PRE-PROJECT f: , FLOODWAY LINE
PARCEL D
(5.78 AC)
(NOT APART OF HABITAT
MmGATIOH PROJECT)
COLLEGE BLVD
FRONTAGE
IMPROVEMENTS
PER EIR 98-02
Bl.JI"~
PREPARED BY:
■HUNSAKER ~ .A~~C;~~ ;ES
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COLLEGE BLVD HABITAT
MITIGATION PLAN
CITY OF CARLSBAD, CALIFORNIA
R: 1Ht7 &Hyd
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ATTACHMENT 2
HYDROLOGIC SOIL GROUP
33" 8' SS"N
33" 8'45"N
~
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t
473300
~
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~ l
Hydrologic Soil Group-San Diego County Area, California
(1197-pr-<lma-bndy)
4734«) 473400 4735«) 473511) 473640 ,rr.mJ
Map Scale: 1:2,170 t prirted 00 A landscape (11" X 8.5") sheet ----=====---------=======:::,Mems o ~ ro m m ----=====--------========feet 0 100 200 400 ax,
Map projection: Web Mert:ator ComerCXlOldnates: 'IJGS84 Edge tics: UTM Zone 11N 'IJGS84
= Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
Q'.Ill{) ,m,gJ 47.3840
~ ~
!!l
t
~ ~
!!l
t
0 I 33" 8' 55" N
I
i
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~
Ii 33' 8' 45" N
10/24/2019
Page 1 of 5
Hydrologic Soil Group-San Diego County Area, California
(1197-pr-dma-bndy)
MAP LEGEND MAP INFORMATION
Area of Interest {AOI)
O Area of Interest (AOI)
Soils
Soll Rating Polygons
D A
□ ND
DB
0 8/D
□c
0 C/D
D D
D Not rated or not available
Soll Rating Lines
A
ND
-B
-8/D
C
CID
D
,. " Not rated or not available
Soll Rating Points
■ A
■ ND
■ B
■ 8/D
USOo\ Natural Resources am Conservation Service
• ■
C
CID
■ D
□ Not rated or not available
Water Features
Streams and Canals
Transportation
+++ Rails
-Interstate Highways
-us Routes
Major Roads
Local Roads
Background
• Aerial Photography
Web Soil Survey
National Cooperative Soil Survey
The soil surveys that comprise your AOI were mapped at
1:24,000.
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil
line placement. The maps do not show the small areas of
contrasting soils that could have been shown at a more detailed
scale.
Please rely on the bar scale on each map sheet for map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL:
Coordinate System: Web Mercator (EPSG:3857)
Maps from the Web Soil Survey are based on the Web Mercator
projection, which preserves direction and shape but distorts
distance and area. A projection that preserves area, such as the
Albers equal-area conic projection, should be used if more
accurate calculations of distance or area are required.
This product is generated from the USDA-NRCS certified data as
of the version date(s) listed below.
Soil Survey Area: San Diego County Area, California
Survey Area Data: Version 14, Sep 16, 2019
Soil map units are labeled (as space allows) for map scales
1 :50,000 or larger.
Date(s) aerial images were photographed: Nov 3, 2014-Nov
22, 2014
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor
shifting of map unit boundaries may be evident.
10/24/2019
Page 2 of 5
Hydrologic Soil Group-San Diego County Area, California
Hydrologic Soil Group
Map unit symbol Map unit name Rating
HrD Huerhuero loam, 9 to 15 D
percent slopes
>----------HrE2 Huerhuero loam, 15 to D
30 percent slopes,
eroded --------
Rm Riverwash D
--..... ---I-----
SbC Salinas clay loam, 2 to 9 C
percent slopes -TuB Tujunga sand, O to 5 A
percent slopes
I-
VaB Visalia sandy loam, 2 to A
5 percent slopes
Totals for Area of Interest ------~-
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
Acres inAOI
2.0
--·-
0.1
-
3.1
-
1.2
-
1.1
1.2
8.7 -
1197-pr-dma-bndy
Percent of AOI
--
-
23.4%
1.5%
35.9%
13.6%
12.3%
-
13.3%
---
100.0%
10/24/2019
Page 3 of 5
,-
Hydrologic Soil Group-San Diego County Ar~~alifornia ....,,
~
Description
Hydrologic soil groups are based on estimates of runoff potential. Soils are
assigned to one of four groups according to the rate of water infiltration when the
soils are not protected by vegetation, are thoroughly wet, and receive
precipitation from long-duration storms.
The soils in the United States are assigned to four groups {A, B, C, and D) and
three dual classes (AID, BID, and C/D). The groups are defined as follows:
Group A. Soils having a high infiltration rate (low runoff potential) when
thoroughly wet. These consist mainly of deep, well drained to excessively
drained sands or gravelly sands. These soils have a high rate of water
transmission.
Group B. Soils having a moderate infiltration rate when thoroughly wet. These
consist chiefly of moderately deep or deep, moderately well drained or well
drained soils that have moderately fine texture to moderately coarse texture.
These soils have a moderate rate of water transmission.
Group C. Soils having a slow infiltration rate when thoroughly wet. These consist
chiefly of soils having a layer that impedes the downward movement of water or
soils of moderately fine texture or fine texture. These soils have a slow rate of
water transmission.
Group D. Soils having a very slow infiltration rate (high runoff potential) when
thoroughly wet. These consist chiefly of clays that have a high shrink-swell
potential, soils that have a high water table, soils that have a claypan or clay
layer at or near the surface, and soils that are shallow over nearly impervious
material. These soils have a very slow rate of water transmission.
If a soil is assigned to a dual hydrologic group (AID, BID, or C/D), the first letter is
for drained areas and the second is for undrained areas. Only the soils that in
their natural condition are in group D are assigned to dual classes.
Rating Options
Aggregation Method: Dominant Condition
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Hydrologic Soil Group-San Diego County~. California 0
Aggregation is the process by which a set of component attribute values is
reduced to a single value that represents the map unit as a whole.
A map unit is typically composed of one or more "components". A component is
either some type of soil or some nonsoil entity, e.g., rock outcrop. For the
attribute being aggregated, the first step of the aggregation process is to derive
one attribute value for each of a map unit's components. From this set of
component attributes, the next step of the aggregation process derives a single
value that represents the map unit as a whole. Once a single value for each map
unit is derived, a thematic map for soil map units can be rendered. Aggregation
must be done because, on any soil map, map units are delineated but
components are not.
For each of a map unit's components, a corresponding percent composition is
recorded. A percent composition of 60 indicates that the corresponding
component typically makes up approximately 60% of the map unit. Percent
composition is a critical factor in some, but not all, aggregation methods.
The aggregation method "Dominant Condition" first groups like attribute values
for the components in a map unit. For each group, percent composition is set to
the sum of the percent composition of all components participating in that group.
These groups now represent "conditions" rather than components. The attribute
value associated with the group with the highest cumulative percent composition
is returned. If more than one group shares the highest cumulative percent
composition, the corresponding "tie-break" rule determines which value should
be returned. The "tie-break" rule indicates whether the lower or higher group
value should be returned in the case of a percent composition tie. The result
returned by this aggregation method represents the dominant condition
throughout the map unit only when no tie has occurred.
Component Percent Cutoff: None Specified
Components whose percent composition is below the cutoff value will not be
considered. If no cutoff value is specified, all components in the database will be
considered. The data for some contrasting soils of minor extent may not be in the
database, and therefore are not considered.
Tie-break Rule: Higher
The tie-break rule indicates which value should be selected from a set of multiple
candidate values, or which value should be selected in the event of a percent
composition tie.
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
1197-pr-dma-bndy
10/24/2019
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