HomeMy WebLinkAboutPRR24079 2015-03-31 Avocet Final Remediation PlanFINAL REMEDIAL ACTION PLAN
San Luis Obispo Tank Farm
276 Tank Farm Road
San Luis Obispo, California
March 31, 2015
PREPARED FOR
Chevron Environmental Management Company
276 Tank Farm Road
San Luis Obispo, California 93406
PREPARED BY
Avocet Environmental, Inc.
1 Technology Drive, Suite C515
Irvine, California 92618-5302
Robert Van Hyning, P.E.
Principal
Project No. 1306.005
FINAL REMEDIAL ACTION PLAN
San Luis Obispo Tank Farm
276 Tank Farm Road
San Luis Obispo, California
March 31, 2015
March 31, 2015 Project No. 1306.005
Mr. Andy Smith
CHEVRON ENVIRONMENTAL MANAGEMENT COMPANY
276 Tank Farm Road
San Luis Obispo, California 93401
Final Remedial Action Plan
San Luis Obispo Tank Farm
276 Tank Farm Road
San Luis Obispo, California
Dear Mr. Smith:
Enclosed is the Final Remedial Action Plan for the San Luis Obispo Tank Farm. The plan has
been revised to address comments from the Regional Water Quality Control Board, County Public
Health Department, County Air Pollution Control District, and California Department of Fish and
Wildlife.
If you have any questions or require additional information, please do not hesitate to call.
Respectfully submitted,
AVOCET ENVIRONMENTAL, INC.
Robert Van Hyning, P.E.
Principal
RVH:sh
Enclosure
P:\1306 ChevronEMC_SLOTF\RAP Update 2015\Final RAP_2015-03-31.docx
Final Remedial Action Plan
Chevron San Luis Obispo Tank Farm Page i
San Luis Obispo, California March 31, 2015
TABLE OF CONTENTS
Page
LIST OF TABLES ....................................................................................................................... iv
LIST OF FIGURES ...................................................................................................................... v
LIST OF ABBREVIATIONS AND ACRONYMS .................................................................. vii
1.0 INTRODUCTION ................................................................................................................ 1
1.1 REMEDIAL ACTION PLAN PURPOSE AND FRAMEWORK .................................................. 1
1.2 SCOPE OF THE REMEDIAL ACTION PLAN ........................................................................ 2
1.3 OTHER PLANS ................................................................................................................ 3
1.4 FINAL CERTIFICATION REPORT ...................................................................................... 3
2.0 BACKGROUND INFORMATION .................................................................................... 5
2.1 CURRENT CONDITION .................................................................................................... 8
2.1.1 Offsite Utilities.................................................................................................. 9
2.1.2 Operations Related Pipelines ............................................................................ 9
2.1.3 Potential Land Use ............................................................................................ 9
2.2 SITE HYDROLOGY ........................................................................................................ 10
2.3 WETLANDS AND RARE PLANT HABITAT ...................................................................... 11
2.4 SITE CHARACTERIZATION SUMMARY .......................................................................... 11
2.5 UPDATED HUMAN HEALTH RISK ASSESSMENT UPDATE .............................................. 14
3.0 OPERABLE UNITS, AREAS OF CONCERN, AND THE INTEGRATED
PREFERRED REMEDY ................................................................................................... 15
3.1 OU #1- FORMER NW OPERATIONS AREA .................................................................... 16
3.1.1 AOC #1 - Groundwater ................................................................................... 17
3.1.2 AOC #2 - Soil ................................................................................................. 18
3.2 OU #2- RESERVOIRS 5 AND 7 ....................................................................................... 18
3.3 OU #3- RESERVOIR 4 (EAST DEVELOPMENT AREA) .................................................... 19
3.4 OU #4- REMAINING SITE-WIDE TERRESTRIAL AND WATERS/WETLANDS AREAS ........ 20
3.4.1 AOC #1 - North Marsh Complex.................................................................... 21
3.4.2 AOC #2 - Reservoir 3 ..................................................................................... 22
3.4.3 AOC #3 - Pliable Surface Expressions of Petroleum ..................................... 22
3.4.4 AOC #4 – Arsenic ........................................................................................... 23
3.5 OU #5- SITE-WIDE GROUNDWATER ............................................................................ 23
4.0 GENERAL REMEDIAL ACTIONS ................................................................................ 25
4.1 LONG-TERM MONITORING ........................................................................................... 25
4.2 REMOVAL EXCAVATIONS ............................................................................................ 26
4.3 CAPS ............................................................................................................................ 28
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Page
5.0 EARTH CONSTRUCTION MATERIALS ..................................................................... 29
5.1 COMMON FILL ............................................................................................................. 29
5.2 STRUCTURAL FILL ....................................................................................................... 29
5.3 GRAVEL ....................................................................................................................... 29
5.4 TOPSOIL ....................................................................................................................... 30
5.5 EARTH MATERIAL SOURCES ........................................................................................ 30
5.5.1 Flower Mound/OU #3 ..................................................................................... 31
5.5.2 Berms .............................................................................................................. 31
5.5.3 Borrow No. 1 .................................................................................................. 32
5.5.4 Borrow No. 2 .................................................................................................. 32
5.5.5 Borrow No. 3 .................................................................................................. 32
5.5.6 Oxbow Borrow................................................................................................ 33
6.0 SITE-WIDE REMEDIAL ACTIONS .............................................................................. 34
6.1 MOBILIZATION, STAGING AREAS, AND SITE ACCESS ................................................... 34
6.2 BUILDING DEMOLITION ............................................................................................... 36
6.3 MISCELLANEOUS CLEANUP ......................................................................................... 36
6.4 PIPELINE REMOVAL AND ABANDONMENT ................................................................... 37
6.4.1 Pipeline Inventory ........................................................................................... 38
6.4.2 Pipeline Flushing and Pigging ........................................................................ 38
6.4.3 Pipeline Grouting ............................................................................................ 39
6.4.4 Pipeline Segment Removal ............................................................................. 39
6.5 MONITORING WELL DESTRUCTION .............................................................................. 40
6.6 HISTORICAL WATER WELLS ........................................................................................ 40
6.7 RESERVOIR 2 BERM REMOVAL .................................................................................... 41
6.8 LAND USE COVENANTS ............................................................................................... 41
6.9 VAPOR BARRIERS ........................................................................................................ 42
7.0 OPERABLE UNIT REMEDIAL ACTIONS ................................................................... 43
7.1 OU #1 - NW OPERATIONS AREA ................................................................................. 43
7.1.1 AOC #1 - Groundwater ................................................................................... 43
7.1.2 AOC #2 - Soil-Development Scenario ........................................................... 43
7.2 OU #2 - RESERVOIRS 5 AND 7 ...................................................................................... 50
7.3 OU #3 - RESERVOIR 4 .................................................................................................. 55
7.4 OU #4 - REMAINING SITE-WIDE TERRESTRIAL AND WETLAND AREAS ....................... 59
7.4.1 AOC #1 - North Marsh ................................................................................... 59
7.4.2 AOC #2 - Reservoir 3 ..................................................................................... 61
7.4.3 AOC #3 - Other Sticky Hydrocarbon Surface Expressions ............................ 64
7.4.4 AOC #4 - Arsenic ........................................................................................... 64
7.5 OU #5 - SITE-WIDE GROUNDWATER ........................................................................... 65
8.0 IMPACTS TO NATURAL RESOURCES AND MITIGATION .................................. 66
9.0 LONG-TERM MAINTENANCE ..................................................................................... 67
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Page
10.0 SCHEDULE ........................................................................................................................ 69
REFERENCES ............................................................................................................................ 70
TABLES
FIGURES
APPENDIX A: REPORT CD
APPENDIX B: MONITORING AND REPORTING PROGRAM 93-120 AND
SUPPORTING DOCUMENTS
APPENDIX C: REMEDIAL DESIGN DRAWINGS
APPENDIX D: RESERVOIR 2 – WALL DEMOLITION AND BERM GRADING
APPENDIX E: EARTH MATERIALS SPECIFICATIONS
APPENDIX F: QUANTITY CALCULATIONS
APPENDIX G: HYDROLOGY CALCULATIONS
APPENDIX H: SETTLEMENT CALCULATIONS
APPENDIX I: GEOSYNTHETIC CALCULATIONS
APPENDIX J: SOIL LOSS CALCULATIONS
APPENDIX K: MODIFICATIONS TO PROJECT DESCRIPTION TO ADDRESS
ELEVATED ARSENIC CONCENTRATIONS
APPENDIX L: PIPELINE QUANTITY ESTIMATE
APPENDIX M: VAPOR BARRIER ENGINEERING GUIDELINES
APPENDIX N: AGENCY COMMENTS REGARDING RAP AND RESPONSE TO
COMMENTS
APPENDIX O: UPDATED HUMAN HEALTH RISK ASSESSMENT,
JANUARY 30, 2013
APPENDIX P: NATURALLY OCCURRING ASBESTOS REPORT (PADRE 2012)
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LIST OF TABLES
Table No. Title
1 Summary of Operable Units and Preferred Remedies
2 List of Active Monitoring Wells and Wells Proposed for
Abandonment
3 Estimated Borrow Source Quantities
4 Estimated Remediation Construction Quantities
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LIST OF FIGURES
Figure No. Title
1 Site Location Map
2 Site Map
3 Northwest Operations Area Historical and Current Features
4 Existing Utilities
5 Chevron Pipelines
6 Detail Plan of Chevron Pipelines in Northwest Operations
Area
7 Existing San Luis Obispo County Land Use Plan
8 City of San Luis Obispo AASP Land Use Plan
9 Constraints to the Proposed City of San Luis Obispo Land
Use Plan
10 Proposed Land Use Concept
11 Hydrology Map
12 Wetlands, Fairy Shrimp, and Rare Plant Habitats
13 Summary of Environmental Impacts
14 Overview of Operable Units
15 Proposed Impacted Soil Stockpile Location
16 Borrow Source Location Map
17 Proposed Work Areas, Staging Areas, and Site Access
18 Preliminary Traffic Control Improvements
19 Miscellaneous Cleanup Areas
20 Monitoring Well Network Modifications
21 Northwest Operations Area (OU #1/AOC #2) Demolition
Plan
22 Northwest Operations Area (OU #1/AOC #2) Cap Grading
Plan
23 Northwest Operations Area (OU #1/AOC #2) Section A-A’
24 Northwest Operations Area (OU #1/AOC #2) Section B-B’
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25 Northwest Operations Area (OU #1/AOC #2) Section C-C’
26 Northwest Operations Area (OU #1/AOC #2) Section D-D’
27 Typical Survey Monument
28 Reservoir 5 (OU #2) Demolition Plan
29 Reservoir 7 (OU #2) Demolition Plan
30 Reservoir 5 (OU #2) Cap Grading Plan
31 Reservoir 7 (OU #2) Cap Grading Plan
32 Reservoirs 5 and 7 (OU #2) Typical Section
33 Reservoirs 5 and 7 (OU #2) Typical Cap Details
34 Reservoir 4 (OU #3), Flower Mound, and Borrow No. 2
Work Areas
35 Reservoir 4 (OU #3) Demolition Plan
36 Flower Mound Demolition Plan
37 Reservoir 4 (OU #3) Excavation and Geotextile Placement
Plan
38 Reservoir 4 (OU #3) Cap Grading Plan
39 Borrow Area No. 2 Grading Plan
40 Reservoir 4 (OU #3) Typical Cap Section and Details
41 North Marsh (OU #3/AOC #1) Demolition and Excavation
Plan
42 Reservoir 3 (OU #3/AOC #2) Demolition and Excavation
Plan
43 Reservoir 3 (OU #3/AOC #2) Grading Plan
44 Reservoir 3 (OU #3/AOC #2) Typical Section
45 Other PPSH-Impacted Areas
46 Areas of Habitat Impact
47 Preliminary Schedule
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LIST OF ABBREVIATIONS AND ACRONYMS
AASP San Luis Obispo Airport Area Specific Plan
amsl above mean sea level
AOC area of concern
APCO Air Pollution Control Officer
ARB Air Resources Board
AST aboveground storage tank
ASTM ASTM International
bgs below ground surface
BMP Best Management Practice
BTEX benzene, toluene, ethyl benzene, and total xylenes
Cal/OSHA California Division of Occupational Safety and Health
CD compact disc
CDFW California Department of Fish and Wildlife
CERCLA Comprehensive Environmental Response, Compensation and Liability Act
EC engineering control
ERWG Ecological Risk Working Group
FEIR Final Environmental Impact Report
FML flexible membrane liner
FS Feasibility Study
GIS Geographic Information System
GPS Global Positioning System
HDPE high density polyethylene
HHRA Human Health Risk Assessment
HHRWG Human Health Risk Working Group
IC institutional control
LNAPL light nonaqueous-phase liquid
MCL maximum contaminant level
MRP Monitoring and Reporting Program
NCP National Oil and Hazardous Substances Pollution Contingency Plan
NHIS Non-hazardous Hydrocarbon Impacted Soils
OSHA U.S. Occupational Safety and Health Administration
OU operable unit
PAH polynuclear aromatic hydrocarbon
PDF portable document format
PG&E Pacific Gas and Electric Company
PVC polyvinyl chloride
RAP Remedial Action Plan
RPZ runway protection zone
RTP Remediation Technology Panel
RWQCB California Regional Water Quality Control Board
SERRT Surface Evaluation, Remediation and Restoration Team
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SLO San Luis Obispo
SLOAPCD San Luis Obispo County Air Pollution Control District
SWPPP Storm Water Pollution Prevention Plan
TEPH total extractable petroleum hydrocarbons
TPH total petroleum hydrocarbons
TPPH total purgeable petroleum hydrocarbons
µg/L microgram per liter
USFWS U.S. Fish and Wildlife Service
UST underground storage tank
VPFS vernal pool fairy shrimp
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San Luis Obispo, California March 31, 2015
1.0 INTRODUCTION
Chevron 1 owns an approximate 332-acre former tank farm property south of the city of San Luis
Obispo (Figure 1), in San Luis Obispo County, which was constructed in 1910 to serve as the
accumulation point for a petroleum pipeline from the San Joaquin Valley. This property,
commonly referred to as the San Luis Obispo Tank Farm, SLO Tank Farm, or Tank Farm, was
slowly withdrawn from operation during the later decades of the twentieth century, and by the late
1990s, was formally decommissioned. A long history of industrial activity on the property,
however, has affected its environmental condition.
Chevron now intends to remediate the property and convert it to alternative uses that are consistent
with local planning, community needs, good environmental stewardship, regulatory requirements,
and efficient asset management. On March 15, 2007, Avocet Environmental, Inc. (Avocet)
published the Feasibility Study, Former San Luis Obispo Tank Farm (FS) addressing the nature of
the environmental impacts and recommending a set of preferred remedial alternatives. A Revised
Remedial Action Plan (RAP), dated August 13, 2014, was prepared to incorporate the final project
description from the Final Environmental Impact Report (FEIR) and update the anticipated
implementation of the preferred remedial alternatives.
The California Regional Water Quality Control Board (RWQCB) provided the August 2014
Revised RAP to agencies for a final review. Comments were received from three agencies:
• County of San Luis Obispo Health Agency, Public Health Department
• County of San Luis Obispo Air Pollution Control District
• California Department of Fish and Wildlife, Office of Spill Prevention and
Response
Appendix N includes correspondence and matrices with response to comments from each of the
three agencies.
The project description and details in this RAP will be further refined as detailed engineering plans
are prepared and land use and construction/grading permits are processed. The engineering plans
for remedial actions will be reviewed with the RWQCB prior to implementation.
1.1 REMEDIAL ACTION PLAN PURPOSE AND FRAMEWORK
This RAP is intended to provide federal, state, and local regulatory agencies, the municipalities
with jurisdiction over the site, and other stakeholders detailed information on how Chevron will
implement the preferred remedial alternative from the FS. It provides preliminary detailed
engineering, which is the basis for design of the preferred remedial alternative components. It also
1 This property is owned and was originally operated by Union Oil Company of California (Union Oil). Chevron
acquired Union Oil, including this property, in August 2005. Chevron personnel manage this project and “Chevron”
is used interchangeably with Union Oil in this document.
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provides conceptual-level information on ecosystem restoration to support preparation of the
grading plans, which will be necessary to permit this project.
This document is built upon a foundation of cooperative agreements and extensive vetting with
the regulatory community, stakeholders, and local municipalities. As with the FS, the RAP has
followed the general framework for developing site remediation documents found in the National
Oil and Hazardous Substances Pollution Contingency Plan (NCP). It has been adapted, however,
to meet the needs of a non-CERCLA (Comprehensive Environmental Response, Compensation
and Liability Act) site regulated by local agencies.
Working cooperatively with the various agencies to develop this plan has resulted in an approach
with broad consensus and support. Nevertheless, it is understood that approvals and permits must
be granted by these agencies independent of the cooperative process. Chevron will work with the
regulatory agencies and municipalities to obtain the permits and approvals required to conduct
remediation at the site.
This RAP describes the remedial actions in detail and also includes information for activities that
support or will be done in conjunction with remediation, but are not remedial actions themselves.
A primary purpose of the RAP is to define the remedial actions to be considered and approved by
the RWQCB. Although this RAP discusses the supporting and concurrent activities, the scope of
the RWQCB approval is limited to the remedial actions, which are summarized in Table 1.
1.2 SCOPE OF THE REMEDIAL ACTION PLAN
Ecological risks are the basis of remedial actions in the open space areas. Where remediation
coincides with developable areas, the remedial approach ensures compatibility with allowable
uses.
This report provides the reader with a brief background of the site, its current condition, and an
overview of the operable units (OUs) and the associated preferred remedies developed in the FS.
Subsequent sections of the report describe implementation of those remedies and present the
supporting engineering analyses. Preliminary engineering drawings and specifications are
included in the appendices. The drawings, which are presented as portable document format (PDF)
files on the CD in Appendix A, are included as both Arch D (24” x 36”) and tabloid (11” x 17”)
size format.
This RAP also describes closure activities that were not relevant to the FS, such as the approach
for abandoning pipelines or demolishing structures. These closure activities were not identified as
critical for evaluation in the FS or previous risk management documents, since they do not pose a
direct threat to human or ecological receptors. They are included in this RAP, as they affect
implementation of the remedies and how they will be conducted.
After publication of the FS, further environmental studies as well as an extension of Runway 11-29
at the nearby San Luis Obispo Regional Airport (Figure 1) resulted in some modifications to the
implementation approach proposed in the 2007 RAP (Avocet, December 18, 2007). The 2007
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RAP provided the basis for a project evaluation, Chevron Tank Farm Remediation and
Development Project, and the FEIR, prepared by Marine Research Specialists, dated December
2013, SCH #2009031001. This Revised RAP updates the remedial aspects of the project as
outlined in the FEIR project description, evaluation, and mitigation measures.
The project requires changes to the City of San Luis Obispo’s existing Airport Area Specific Plan
([AASP] 2005) to incorporate the proposed land uses, which are a combination of restoration, open
space, and development.
This report provides a brief overview of long-term maintenance items. It describes the general
activities that will be performed to ensure continued achievement of the remedial objectives. The
report also discusses the alternatives under consideration for future management of open space.
While the primary objective of this process has been to protect human and ecological receptors
from exposure to potentially harmful substances, a secondary objective has been to maintain and,
if possible, improve the function of various ecosystems and/or habitats that occur on the SLO Tank
Farm site. Key among these are the wetlands and other waters, vernal pool fairy shrimp (VPFS),
and rare plant habitats. The RAP provides preliminary information regarding the areas of these
various habitats anticipated to be impacted by project activities. The specific impacts will be
evaluated at the time of project implementation and requirements for habitat restoration and
mitigation will be determined in an agency-approved Restoration Plan.
1.3 OTHER PLANS
The RAP has been prepared to accompany other plans and guiding documents for remediation,
restoration, and permitting of this site. Other plans that support the RAP, which are either included
as appendices to this report or are incorporated in the Project Execution Plan (Padre, 2007b), are
conceptual or draft and will be finalized as needed for project permitting and implementation.
Documents that are discussed in the text include the Geotechnical Report (Padre, 2007a) and Land
Use Covenants. The Geotechnical Report supports the engineering basis for the cap designs. Land
Use Covenants are restrictions on the property recorded with the deed, making the requirements
binding upon future property owners. Specific Land Use Covenants will be developed for each
property by Chevron legal representatives and will be provided to the RWQCB for review in
consultation with the County of San Luis Obispo Environmental Health Services, concurrence,
and signature, as needed.
1.4 FINAL CERTIFICATION REPORT
Once remediation is complete, Chevron will submit a report documenting that the remedial action
objectives of this plan were met. It is anticipated that reports will be provided for individual areas
of the site as the remedial actions are completed in each area. For development areas, the report(s)
will include applicable post-remediation soil gas sampling (a work plan will be submitted prior to
beginning the work) and, based on sampling results, any recommended land use covenants and
engineering controls for specific parcels. Approval of the land use covenants will be coordinated
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through the RWQCB. Those parts of the covenants dealing with vapor intrusion issues will be
referred to the local agency with jurisdiction. Once the report is approved and the land use
covenants are recorded the RWQCB will issue a letter of concurrence that the remedial actions for
the area addressed in the report were properly implemented.
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2.0 BACKGROUND INFORMATION
The following section is intended to quickly acquaint the reader with the history, operations, and
general background information pertaining to the SLO Tank Farm. Information presented herein
is largely taken from the background discussion provided in the FS, but has been edited and is a
somewhat more brief summary. Readers desiring more detailed information are referred to the FS
and other background documents listed in the References section of this report.
Chevron’s approximately 332-acre Tank Farm is located at 276 Tank Farm Road in western San
Luis Obispo County, south of the city of San Luis Obispo and northwest of the municipal airport
(Figure 1). The site is divided into north and south sections by Tank Farm Road, and is bordered
by light commercial and industrial development, the San Luis Obispo County airport, agricultural
and pastoral lands, with scattered residences and a trailer park. The existing buildings in the
northwest part of the site currently serve as Chevron’s local offices for a variety of environmental
and remediation operations (Figure 2).
From 1910 until the early 1980s, the SLO Tank Farm was used for storing crude oil transported
via pipeline from the San Joaquin Valley. Storage facilities at the site included 6 large earthen
reservoirs, ranging in capacity between 775,000 and 1,350,000 barrels 2, and 21 steel aboveground
storage tanks (ASTs) capable of holding 55,000 barrels each. The reservoirs were constructed by
excavating a circular or elliptical depression, which was then lined with wire-mesh-reinforced
2 One barrel is equivalent to 42 gallons.
Construction of Reservoir 4 – August 25, 1910
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concrete. The walls were also reinforced concrete, but were constructed either vertically or
integrated into the sloping sides of the depression. The walls and floors of the ASTs were
constructed of heavy plate steel secured with rivets. The roofs of both the reservoirs and ASTs
were of wood and composition. All told, the site had the capacity to store over 6 million barrels
of petroleum.
On April 7, 1926, a lightning strike ignited a fire at the Tank Farm. At that time, there were
933,577 barrels of oil stored in the ASTs, and another 5,374,927 barrels of oil were stored in the
reservoirs. The total inventory was 6,308,504 barrels of oil of various grades. Eyewitnesses claim
that a lightning strike simultaneously ignited the vapors in Reservoirs 5, 6, and 7. The power of
the resulting explosion registered on the Weather Bureau barograph in downtown San Luis Obispo,
which recorded the time as 7:35 a.m. A second lightning strike ignited Reservoir 3 sometime
between 7:50 and 7:55 a.m.
Despite suppression efforts by the facility staff, the fire spread to the other reservoirs and to 12 of
the existing 15 steel ASTs over the course of the next four days by a combination of burning
embers and boil-overs, where the heated oil flowed out of the reservoirs and onto the ground
surrounding the tanks. By April 11, 1926, all but a few thousand of the six million barrels in
inventory had been burned to coke and spread across the site. This release is considered
responsible for most of the numerous surface occurrences (i.e., expressions) of highly weathered
and burned petroleum that cover the ground in topographically low areas of the Tank Farm.
Morning of April 9, 1926. Reservoir 4 (left) has been extinguished. Reservoir 2 and ASTs (right)
are still burning.
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Subsequent to the 1926 fire, Union Oil resumed operations at the Tank Farm, including
reconstructing ten of the steel ASTs and four of the reservoirs (Reservoirs 3, 4, 5, and 6).
Reservoirs 2 and 7 were never again used for petroleum storage. The reconstruction effort included
expanding the fire breaks and enlarging the containment areas surrounding the reservoirs, which
created numerous hydraulically closed depressions around the site. Many of these depressions
subsequently ponded and became wetlands.
In addition to the 6 reservoirs and 21 ASTs utilized for petroleum storage, the facility included a
series of pipelines for oil movement to and from the site and for movement between the onsite
tanks and facilities. Regional pipeline operations were also conducted at the site, primarily from
the northwest area of the property (Northwest Operations Area; Figure 3). Facilities to support
pipeline operations included a pumphouse, boilers (for heating crude oil to reduce viscosity) and
an associated blow-down area, a petroleum physical properties testing laboratory, and an electrical
equipment house (Figure 3). The Northwest Operations Area also included areas for general
equipment storage and maintenance, as well as underground storage tanks (USTs) that contained
diesel fuel and gasoline (England, Shahin & Associates, May 11, 1994). The USTs were removed
in 1987.
Other historical activities at the site include the operation of a fire training school in the unpaved
eastern portion of the Northwest Operations Area (Figure 3). The school consisted of several
simulated sumps, flares, and tanks where students would practice techniques for extinguishing
petroleum-fed fires. Off-specification gasoline and diesel fuel were fed to these fixtures from a
set of three ASTs via a system of buried metal pipes.
The four reservoirs repaired after the 1926 fire continued in service for several more decades, but
were progressively decommissioned beginning in the late 1950s and continuing into the mid-
1970s, according to the following schedule:
Reservoir
Date
Decommissioned
5 1959
3 1961
6 1961
4 1976
Field evidence suggests that decommissioning involved emptying the reservoirs of liquid
petroleum and removing the roofs and, at Reservoirs 3 and 4, the vertical walls. The reinforced
concrete covering the sloping slides and bottoms was left in place. In Reservoirs 2, 5, and 7, there
is evidence that the concrete bottoms were ripped by the shank of a bulldozer in perpendicular
directions. The bottoms of the remaining reservoirs have not been directly observed, so it is
uncertain whether these have been similarly ripped. It is anecdotally reported that the ripping was
done to prevent water from accumulating in the former reservoirs. Reservoirs 3 and 4 were largely
backfilled by bulldozing the berms into the center of the reservoirs. Reservoir 4 generally contains
5 to 6 feet of non-engineered fill and construction debris above the concrete bottom, and Reservoir
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3 is estimated to contain between 8 and 11 feet of non-engineered fill. To provide access, a portion
of the berms surrounding Reservoirs 5, 6, and 7 has been pushed into the reservoirs.
Approximately 1.5 feet of non-engineered fill and construction debris cover the bottoms of
Reservoirs 5 and 6, and in Reservoir 7 the berm debris was not distributed evenly across the
reservoir bottom, but rather was left as an apron near the notch. Most of the bottom of Reservoir
7 is covered by several inches of interlayered tar and organic debris.
A review of historical aerial photographs shows that the ten steel ASTs remaining or rebuilt after
the 1926 fire were decommissioned at various times. AST 522, located in the Northwest
Operations Area, was removed sometime between 1959 and 1965. Eight of the nine remaining
ASTs were removed in 1994, with the last AST being reserved for fire water storage. The final
AST was removed in August 2000. Fire school exercises were suspended at the Tank Farm in the
1970s and transferred to the Richmond refinery. The pumphouse, pipelines, and boilers were taken
out of service in the early 1990s and were demolished or decommissioned in the late 1990s. Of
the original Tank Farm structures, only three buildings in the operation remain.
For several years, approximately 2 acres of land near the center of the property north of Tank Farm
Road were leased to a recycling company. The site was used as a transfer station and accumulation
point for recyclable materials such as paper, glass, and aluminum. The operation was shut down
and removed in mid-2000, when the lease expired, and was not renewed (England Geosystem,
April 17, 2001).
2.1 CURRENT CONDITION
Aside from the current Chevron office buildings situated in the northwestern portion of the
property, the site presently consists of undeveloped land that supports native grasslands, riparian
areas, and riverine, depressional, and other wetland areas (waters/wetlands) (Figure 2). The site is
best characterized as open space, with cattle grazing for the purpose of fire prevention and weed
control. Adjacent land uses include light commercial and industrial development, the San Luis
Obispo County Regional Airport, agricultural and pastoral land with scattered residences, and a
trailer park.
The northeast corner of the site has been referred to as the Flower Mound and is an approximately
17.3-acre outcrop of the basement bedrock complex known as the Franciscan Formation
(Figure 2). Typically referred to as the “Franciscan mélange,” the Franciscan Formation is
comprised of a complex collection of various rock types. Although the Franciscan Formation
found at the Tank Farm includes localized occurrences of coarse to fine-grained clastic
sedimentary rocks, it more commonly consists of highly fractured and weathered metavolcanic
rocks and serpentinite.
Some modifications and improvements have been made to the Northwest Operations Area since
the last petroleum-dedicated ASTs were decommissioned in 1994. These include upgrades to the
front gate, the addition of a modular office building adjacent to the northernmost original building,
a new fire water tank to replace the water storage AST decommissioned in 2000, and various
upgrades to the electrical and telecommunication systems (Figure 3).
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2.1.1 Offsite Utilities
Utility companies as well as local municipalities provide natural gas, electricity,
telecommunication, and sewer service to the site or have lines that cross the site. The locations of
these lines and easements are shown in Figure 4. The Gas Company owns a 4-inch diameter gas
line located just north of Tank Farm Road. The line is buried in the shoulder of the road and
terminates approximately 400 feet from the west boundary of the Northwest Operations Area. A
2-inch diameter gas line tees off the main and runs underground along the western property line
for approximately 500 feet. That branch line provides natural gas service to the Northwest
Operations area. Aerial lines also run parallel to Tank Farm Road, offset to the north
approximately 100 feet from the road centerline. The aerial lines include electrical power provided
by Pacific Gas and Electric Company (PG&E), and telecommunications service provided by
AT&T. Electricity and telecommunications services also branch off the main lines at the west
boundary of the Northwest Operations area, run along the western property line, and serve the
ongoing operations.
2.1.2 Operations Related Pipelines
Historical operations at the site were served by approximately 25,125 feet of crude oil pipeline,
47,340 feet of water supply line, and 1,172 feet of other pipeline. The approximate locations of
these lines are shown in Figure 5. The analyses supporting the estimated lengths of pipeline are
found in Appendix L. It is believed that most of the lines were abandoned in place, although it is
reported anecdotally that much of the pipeline serving the ASTs was removed when the tanks were
removed. Since there is no record of final cleaning or abandonment procedures, it is presumed
that at least some of the lines still contain crude oil. Crude oil pipelines vary in diameter from 8 to
16 inches. It appears that the most common diameter is 8 inches, and using this as a nominal
diameter for the entire network suggests that the crude oil pipeline volume is on the order of
16,750 cubic feet. It is unlikely, however, that this volume of oil remains in the lines. Many of
the lines are demonstrably empty where they are exposed on the surface.
Much of the facility piping is found in the Northwest Operations Area, as shown in Figure 6. This
includes nearly 20 percent of the total crude oil pipe network (approximately 4,300 lineal feet).
This configuration allowed the operators to direct oil in and out of the facility and to transfer oil
between the various storage locations as needed. There are also 4,900 feet of water line, 1,120 feet
of dedicated Foamite fire-fighting lines, and leach and drain lines totaling slightly less than 1,200
feet. The estimated volume of the crude oil lines in the Northwest Operations Area is
approximately 3,260 cubic feet.
2.1.3 Potential Land Use
After remediation, Chevron intends to convert the site to new uses consistent with the revised land
use plans for the area. As noted previously in this report, the site is within unincorporated San
Luis Obispo county; however, annexation of the Tank Farm into the City as part of the AASP (City
of San Luis Obispo, 2005) may occur. Chevron is working with the City of San Luis Obispo, San
Luis Obispo County, and other stakeholders to ensure that the relevant land use plans and proposed
reuse are aligned. The SLO County General Plan envisions future development on portions of the
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Tank Farm (Figure 7). Potential land uses for the site under the City plan are shown in Figures 8
and 10 and detailed discussions can be found in Section 2.0 of the FEIR. Regardless of whether
the Tank Farm remains within San Luis Obispo County or becomes annexed into the City of San
Luis Obispo, remediation of the site will support the appropriate land use plans.
Cattle grazing may continue in the grassland areas of the future open space. Cattle are effective at
controlling invasive weeds and limiting the fuel available to a potential fire. It is expected that
cattle grazing would be excluded from upland and wetland restoration areas, but specific
requirements for continued cattle grazing will be coordinated with the Open Space Manager, the
California Department of Fish and Wildlife (CDFW), the U.S. Fish and Wildlife Service
(USFWS), and other appropriate agencies.
2.2 SITE HYDROLOGY
Regionally, the Tank Farm is within the Central Coast Hydrologic Area, a 6,600-square-mile
watershed that extends from Santa Barbara to the upper reaches of the Nacimiento River. More
specifically, the site is within the San Luis Obispo Hydrologic Subunit, a 44,370-acre component
of the larger San Luis Obispo Hydrologic Unit. The boundaries of these watersheds have been
defined by the California Department of Water Resources and are illustrated in Appendix G.
Locally, the Tank Farm is situated north of the East Fork of San Luis Obispo Creek, which is
tributary to San Luis Obispo Creek, and is illustrated in Figure 11. A small portion of the Tank
Farm discharges to this creek directly, referred to as Design Point B on Figure 11. However, most
of the Tank Farm consists of a closed catchment that retains storm water. This is a legacy of the
historical containment structures and other topographic modifications that were made to facilitate
operations.
Ditches along Tank Farm Road collect storm water from the frontage properties. A local high
point is located approximately 1,000 feet east of Higuera Road. Storm water collected east of this
point drains toward the Tank Farm and eventually discharges into the North Marsh wetland
complex (Figure 2).
A small channel, referred to by the City of San Luis Obispo as Tank Farm Creek, is located on the
western side of the property and collects storm water from a catchment approximately 485 acres
in size, including about 150 acres that are on the Tank Farm proper. Tank Farm Creek discharges
from the site at a concrete outlet works labeled Design Point A on Figure 11. Much of that
catchment is located north of the Tank Farm and currently enters the site as sheet flow, or
concentrated into natural channels, along the northern property line.
Recent development plans and construction in the Margarita Area north of the Tank Farm have
changed the upgradient hydrology slightly and have concentrated flow at the discharge location of
a newly constructed detention basin just north of the northwest corner of the site. Drainage from
this basin flows into the North Marsh, where it is stored and released to the south side of Tank
Farm Road through a series of culverts. Remediation and grading on the east side of the property
will also affect drainage into the North Marsh. Anticipated changes to the onsite hydrologic system
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as a result of remedial activities are discussed in subsequent chapters. Remediation and restoration
of the North Marsh may require further changes to the site hydrology. The details of these changes
will be developed as the Restoration Plan is finalized in conjunction with the regulatory agencies.
The natural retention capacity of the onsite waters/wetlands will be more than adequate to address
any foreseeable hydrologic changes (Avocet, 2009).
2.3 WETLANDS AND RARE PLANT HABITAT
The Tank Farm currently hosts waters/wetlands and rare plant habitats (Figure 12). Much of the
waters/wetlands ecosystems habitat has been established from the closed hydrologic conditions
onsite that are artifacts of the containment and fire suppression controls constructed after the 1926
fire. Several delineations of the waters/wetlands have been accompanied by supporting scientific
studies. This report focuses on the most current delineation, which includes Federal Wetlands
(those that are federally jurisdictional) as well as Other Wetlands (those that are isolated and not
federally jurisdictional). As described in the FEIR project description, the most recent delineation
identified approximately 73.2 acres of Other Wetlands (incorporating approximately 49 acres of
Federal Wetlands and approximately 3.9 acres categorized as Other Waters of the U.S.). This total
also includes approximately 32.6 acres of VPFS habitat. In addition, the site supports several other
rare plant habitats that are identified in Figure 12. Wetland delineation and existing VPFS habitat
will be further discussed in the Restoration Plan to be submitted to the resource agencies for review
and approval.
Remediation activities at the site will impact existing wetlands and other ecological resources.
Estimated impacts to those resources and their associated mitigation, as required by the FEIR, will
be discussed in detail in the Restoration Plan. It is possible that waters/wetlands, VPFS habitat,
and rare plant community estimates will change with subsequent surveys and conditions in the
field during project implementation. Modifications to these surveys will be addressed as part of
the onsite monitoring and restoration efforts.
2.4 SITE CHARACTERIZATION SUMMARY
Considerable effort has been expended to characterize the impacts due to historical industrial
operations at the site. The following is offered as a brief summary to orient the reader who is not
otherwise familiar with that characterization work. It focuses on those portions of the
characterization that are most relevant to the remedial action, including the key soil and water
impacts, waters/wetlands, VPFS, and rare plant habitats, and the environmental impacts considered
pertinent to risk management. For those readers desiring more detailed information on the site
characterization efforts, the documents listed in the reference section are useful.
Given that petroleum storage and handling facilities operated on the property for many decades, it
is not surprising that environmental issues at the site are generally petroleum-related. Crude oil is
found in soil as deep as 60 feet below the ground surface (bgs). Oil is also seen in surface
expressions ranging from solid asphalt-like coke to viscous liquid. The locations and nature of
these impacts are shown in Figure 13.
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Characterization of these impacts has included, in addition to their careful identification and
delineation, an evaluation of their importance relative to human and ecological health, and the
need for their remediation. Key to this effort has been the cooperative process between Chevron
and the regulatory community that has progressively reviewed existing data, evaluated
assessments, identified data gaps, established the risk associated with a given impact, and
determined which impacts require remediation.
In order to validate the characterization process, Chevron entered into two cooperative programs
resulting in regulatory agency participation and third-party expert review: the Remediation
Technology Panel (RTP) and the Surface Evaluation, Remediation and Restoration Team
(SERRT).
The first of these collaborative processes, the RTP, was established through a cooperative
agreement between Chevron and the RWQCB. The RTP consisted of three experts drawn from
academia with expertise in the characterization and remediation of petroleum-affected sites, whose
purview focused on soil- and groundwater-related issues. They identified data gaps within the
existing site characterization, guided and reviewed subsequent characterization activities, and
published a report summarizing their consensus understanding of subsurface issues at the site
(RTP, 2006).
A key finding of that report was that petroleum in the subsurface was effectively immobile and
that the migration of dissolved-phase constituents was controlled by natural biodegradation
processes. This finding, which was supported by a specific evaluation of natural attenuation
processes, formed the basis of evaluating monitored natural attenuation as an appropriate remedial
technology for impacted groundwater.
The second of the cooperative efforts, the SERRT, was established in 2002 at the suggestion of
staff at the RWQCB. This action was suggested in recognition of findings of studies that detailed
the extent of sensitive resources on the site, and the subsequent desire to consider a risk-based
remediation program for the property. As part of the SERRT process, Chevron, regulatory
agencies, and local municipalities have reviewed data, evaluated source, and determined the extent
of the remediation required for the site.
The SERRT formed two subgroups, the Human Health Risk Working Group (HHRWG) and the
Ecological Risk Working Group (ERWG). Both groups included Chevron, its representatives and
consultants, and the RWQCB. In addition, the HHRWG included representatives from the
California Office of Environmental Health Hazard Assessment, the San Luis Obispo County
Environmental Health Division, and the San Luis Obispo County Air Pollution Control District
(SLOAPCD). The ERWG in addition included representatives from the City, the County Planning
Department, CDFW, USFWS, and the U.S. Army Corps of Engineers.
In addition to preparing reports documenting the Human Health Risk Assessment (HHRA) and
Predictive Ecological Risk Assessment, the SERRT prepared a consensus summary document
listing its recommendations for risk management at the site, the Risk Management Summary
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(BBL, 2005). In order to focus risk assessment efforts, certain areas of the site, mainly those
affected by liquid or plastic hydrocarbon surface expressions, were excluded from the risk
assessments with the understanding that remediation of those areas was a “must,” and Chevron
would undertake remediation there without the need for further detailed characterization or
assessment.
Lead exceeding the Childhood Lead Poisoning Prevention Program 1,000 mg/kg threshold for
“areas where children may be present” was found in two shallow soil samples. The SERRT
recognized that these two exceedances were in VPFS habitat. They also determined that the two
lead soil exceedances are in areas of ecological habitat where young children are unlikely to be
exposed. With these two considerations, the consensus of the SERRT was that the risk of exposure
was so low that it did not warrant disturbing an established habitat for protected species. There
were no other areas where lead was a concern, so it was not carried forward for remedial action in
the RAP.
The culmination of Chevron’s characterization efforts was the Risk Management Summary, which
identified the contamination at the site requires remediation. The SERRT ratified the Risk
Management Summary on December 12, 2005. The Risk Management Summary also provided
recommendations on treatment strategies based on levels and types of contamination, the potential
ecological risks, and the potential impacts of clean-up. Contamination requiring remediation
included surface liquid hydrocarbons impacting seasonal wetlands in Reservoirs 5 and 7, plastic
surface hydrocarbons found across the site (mostly in low-lying areas), groundwater affected by
light nonaqueous-phase liquid (LNAPL) and benzene, arsenic in soil, asphalt affecting wetlands,
and the potential for vapor intrusion to affect buildings.
Based upon the Risk Management Summary, an FS was conducted that considered remedial
activities that supported development consistent with the land use plans available at that time. The
FS evaluated various remedial alternatives that addressed site contamination issues and selected a
preferred remedy. The study was ratified by the SERRT on March 15, 2007.
Following are the principal impacts identified in the various site studies, RTP report, or Risk
Management Plan that were further evaluated in the FS as well as studies developed subsequent to
the publication of the FS, including the updated Human Health Risk Assessment (uHHRA;
McDaniel Lambert, 2013).
• Liquid hydrocarbon surface expressions (red areas in Figure 13) impacting the
wetlands in the bottom of Reservoirs 5 and 7.
• Plastic surface hydrocarbon expressions (purple areas in Figure 13) found across
the site, but predominantly in low-lying areas (e.g., North Marsh, Reservoir 3) that
pose an entrapment hazard to small animals.
• Groundwater affected by LNAPL and benzene beneath the Northwest Operations
area.
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• Arsenic in shallow soil in and north of the Northwest Operations Area and northeast
of Reservoir 2.
• The potential for methane, hydrogen sulfide, and benzene to affect habitable
structures.
2.5 UPDATED HUMAN HEALTH RISK ASSESSMENT UPDATE
The HHRA was updated in 2013 (uHHRA). The uHHRA built on the process agreed upon by the
SERRT during the preparation of the 2004 Baseline HHRA, with modifications related to
incorporation of additional characterization data, the Development Plan exposure areas, and
relevant updates in risk assessment methodologies and toxicity factors. The update did not result
in significant changes to remedial actions already established.
The results of the uHHRA are summarized in Table ES-1, Summary of Potential Health Effects
Associated with Development Areas, included in Appendix O. Also included in Appendix O are
determination letters from the RWQCB, State Office of Environmental Health Hazard Assessment,
and San Luis Obispo County Health Agency, all of which were included in an appendix of the
FEIR.
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3.0 OPERABLE UNITS, AREAS OF CONCERN, AND
THE INTEGRATED PREFERRED REMEDY
Once the SERRT had reached a consensus on the objectives of remediation, it was necessary to
evaluate methods for achieving those goals. Chevron elected to generally follow the procedure
outlined in the NCP, which establishes the framework for evaluation of remedial actions used by
the U.S. Environmental Protection Agency. This procedure provided a transparent and credible
evaluation process for selecting remedial alternatives that was familiar to the regulatory
community.
Through that process, five OUs were developed for the Tank Farm. The four terrestrial OUs are
shown in Figure 14 (OU #5, site-wide groundwater, is not depicted). A brief description of each
OU is provided in the sections below and is accompanied by a discussion of the associated
preferred remedy. These descriptions are largely taken from the FS but have been edited to reflect
the current plan to pursue the development options where applicable, and to reflect refinement of
the AASP (City of San Luis Obispo, 2005) land use zones. Detailed proposals for implementing
the preferred remedies are provided in Sections 4 through 7. A summary list of the operable units,
areas of concern, the relevant constituents of concern, and the preferred remedies is provided in
Table 1.
As part of the preferred remedies, institutional and engineering controls (ICs and ECs) are
proposed to achieve the remediation goals. The various ICs and ECs applicable to specific
locations are listed in Table 1. They are summarized below and will be further discussed later in
this report.
Institutional Controls (ICs):
• Groundwater Use Restrictions – Recorded as negative covenants in the county
records, and would limit or prohibit uses of groundwater under parcels in identified
areas. This may be accomplished in a standalone document(s) and/or as part of the
deed(s) at the time of conveyance.
• Use Restrictions – Recorded as negative covenants in the county records, and would
limit the land use of specified parcels to specific purposes, in this case commercial,
industrial, or open space only. This may be accomplished in a standalone
document(s) and/or as part of the deed(s) at the time of conveyance.
• Notice of Subsurface Chemicals of Concern – Disclosures recorded in the county
records, and would notify all future landowners of present areas where subsurface
chemicals of concern are located to minimize the potential for future exposures
through soil excavation or disturbance. This may be accomplished in a standalone
document(s) and/or as part of the deed(s) at the time of conveyance.
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Engineering Controls (ECs):
• Vapor Barriers – Would be required for any new occupied building/structure
constructed in development areas where vapors from residual contamination could
be generated. Options will include construction on a raised foundation or, if
constructed at grade, a vapor barrier or other appropriate engineering controls.
Vapor barriers are further discussed in Section 6.9.
3.1 OU #1- FORMER NW OPERATIONS AREA
OU #1 encompasses approximately 5 acres in the northwest area of the site. Historically, this area
was used to support tank farm and pipeline operations and included equipment and processes not
found across the remainder of the site. Consequently, this area is affected, at least in part, by a
unique group of contaminants, namely arsenic in shallow soil and LNAPL with a significant lighter
fraction, including benzene, toluene, ethyl benzene, and total xylenes (BTEX), in the saturated
zone.
In addition, this area of the site is designated both by the City and San Luis Obispo County for
potential commercial development (Figure 7, Figure 8, and Figure 10). Although the area zoned
for commercial development in either land use plan includes all or portions of the northwest corner
of the property, including the former AST containment berms, the area of OU #1 excludes the AST
berms due to the VPFS habitat that they support (Figure 12). An additional concern to this operable
unit is that it lies within the 100-year floodplain (Figure 9), which affects how development can
be implemented.
OU #1 includes two media-focused areas of concern (AOCs), groundwater (AOC #1) and soil
(AOC #2). As stated previously, due to a set of conditions unique to the Northwest Operations
Area, the LNAPL in the saturated zone also contains a light fraction (C5-C20), including benzene.
This light fraction is responsible for the Northwest Operations Area being the only area of the site
identified by the RTP where groundwater containing dissolved contaminants (total petroleum
hydrocarbons [TPH] and benzene) at concentrations greater than maximum contaminant levels (or
frequently applied action levels) has migrated offsite. The LNAPL impact in the Northwest
Operations Area covers an area approximately 600 feet long by 300 feet wide and ranges in depth
from 4 to 28 feet bgs (Figure 14). The light fraction co-occurs with, and is dissolved in, the heavier
oil. Light-end hydrocarbons, including BTEX, are hundreds of times more soluble in oil than in
water. Therefore, this light fraction would be difficult to remove without also removing the heavier
residual oil. In the Northwest Operations Area, groundwater typically occurs at depths ranging
from 5 to 15 feet bgs.
Benzene is the most toxic constituent of BTEX and its presence in soil, groundwater, and soil gas
has the potential to pose the greatest potential risk to future users of the site. The FS describes the
circumstances surrounding the presence and discovery of the BTEX in detail. In summary, it was
determined that the BTEX does not pose a significant risk to building occupants, provided
adequate ICs and ECs (e.g., vapor barrier requirements) are in place.
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AOC #2 includes shallow soil in OU #1, which is impacted by arsenic and, to a more limited
extent, by TPH and polynuclear aromatic hydrocarbons (PAHs), and deeper (4 to 28 feet bgs) soil
impacted by the above-described LNAPL. Within the operable unit, the arsenic is relatively
widespread and limited to shallow (<2 feet) soil, which is consistent with its likely use as an
herbicide. Although not relevant to the development plans considered in this report, the metals
and PAHs have been identified as potential ecological risks and there could be issues if the area
were converted to open space 3. However, the proposed remedial cap will address this ecological
risk issue. The arsenic was identified as a potential human health risk for both open space and
commercial development land uses. It is assumed that the entire operable unit is impacted with
arsenic, subject to remediation given the available spatial distribution of data.
AOC #2 was subsequently expanded to include arsenic in an adjacent area approximately 0.21 acre
in size immediately north of the Northwest Operations Area (see Appendix K).
3.1.1 AOC #1 - Groundwater
It has been demonstrated that benzene dissolved in groundwater has historically migrated offsite
in the vicinity of Well SLOW-12, but rapidly attenuates and does not appear to threaten
downgradient water wells. The remedial action objectives for OU #1/AOC #1 established in the
FS are intended to prevent human contact with TPH- or benzene-impacted groundwater and ensure
that groundwater resources downgradient of existing impacts are not affected. Given that the
LNAPL is stable and unrecoverable, the dissolved phase is naturally contained, there is no
evidence of hydrocarbon impacts to downgradient groundwater beneficial uses, and groundwater
in the airport area is not used for drinking, it was concluded that monitored natural attenuation
is sufficiently protective to be adopted as the long-term remedy for groundwater in OU #1/AOC #1.
Therefore, the preferred remedial alternative for AOC #1 is monitored natural attenuation with
ICs, ECs and long-term monitoring. Monitored natural attenuation includes the following:
• Semiannual sampling of the existing groundwater monitoring network on and
surrounding AOC #1;
• Testing those samples for total extractable petroleum hydrocarbons (TEPH), total
purgeable petroleum hydrocarbons (TPPH), BTEX, and natural attenuation
parameters;
• Reporting findings to the RWQCB in accordance with an approved monitoring and
reporting program.
The proposed ICs and ECs for this OU are summarized in Table 1.
3 In its present condition, the Northwest Operations Area was not considered suitable habitat in the pERA.
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3.1.2 AOC #2 - Soil
AOC #2 includes shallow soil, which is impacted by arsenic and, to a more limited extent, by TPH
and PAHs, and deeper (4 to 28 feet bgs) soil impacted by LNAPL containing a light fraction. The
arsenic is relatively widespread and limited to shallow (<2 feet) soil, which is consistent with its
probable former use at the site as a herbicide. The arsenic and PAHs have been identified as
potential threats to human and ecological receptors (if the area were converted to open space).
With regard to the deeper soil, the LNAPL is not considered a direct contact risk, but vapor
intrusion by the volatile fraction may pose a risk to future onsite commercial workers. Remedial
action objectives are primarily focused on preventing human and eco-receptor contact with arsenic,
TPH, PAHs, and volatile hydrocarbons. Since the area is to be developed, it will not support
suitable ecological habitat, thereby mitigating the potential for ecological risks. Furthermore, the
proposed remedial cap will address this ecological risk issue in the event development does not
occur in this area.
The preferred remedy for OU #1/AOC #2 includes construction of a minimum 4-foot-thick soil
cap. The cap will provide a barrier between the impacted soil and potential receptors and also
provide a soil layer of sufficient thickness to facilitate foundation construction and utility
installation with a low potential of disturbing contaminated soil. AOC #2 was expanded to include
surface removal of additional arsenic from an area north of the Northwest Operations Area. The
removed arsenic-affected soil will be consolidated under the cap (see Appendix K).
The Northwest Operations Area is within the 100-year flood plain associated with Tank Farm
Creek. At its current grade, the southernmost structure within the Northwest Operations Area is
subject to inundation during periods of moderate to heavy rain. Raising the ground elevation by 4
feet and regrading appropriately would also satisfy the requirements for construction in floodplains
and help alleviate the current flooding problems. A geotextile would be placed between the cap
and the existing ground surface. It would act as an identifying marker to reduce the likelihood of
inadvertently excavating into the impacted soils. The cap will require long-term monitoring and
maintenance, ICs, and ECs. The proposed ICs and ECs for this OU are summarized in Table 1.
3.2 OU #2- RESERVOIRS 5 AND 7
OU #2 includes the former Reservoirs 5 and 7 (Figure 14). Measured from the outside toe of the
reservoir containment berms, the reservoirs cover a total area of 9.8 acres. The reservoirs contain
delineated wetlands and rare plant communities. Details of wetland and rare plant community
locations will be provided in the Restoration Plan.
Both reservoirs pond water during the winter, with the amount of water largely dependent on the
amount of rainfall. In years of heavy rainfall, it is not unusual for 2 to 3 feet of water to accumulate
in the reservoirs. The reinforced concrete bottoms, though ripped, are still present in both of the
reservoirs but are covered by 1 to 2 feet of tar, non-engineered fill, and construction debris. In all
land use plans, Reservoirs 5 and 7 are in areas designated as Open Space.
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Reservoirs 5 and 7 are unique in that they are the only areas of the site impacted by liquid-type
hydrocarbon surface expressions and these are the only surface expressions that are hydraulically
connected to subsurface LNAPL sources. The implication of this is that simple removal of the
shallow hydrocarbon-impacted soils will not effectively remediate the sheen that seasonally
develops on surface water in the reservoirs. The source of the hydrocarbon sheen is mobile
hydrocarbon extending to depths of up to 25 feet below the bottom of the reservoirs, which is
displaced vertically upward during periods of a rising water table. Elimination of the sheen will
require either removal of the mobile hydrocarbon at depth, making that hydrocarbon immobile, or
raising the bottom of the reservoirs to elevations above the seasonal water table highs (RTP, 2006).
The preferred remedy caps Reservoirs 5 and 7 and provides ICs and ECs and long-term monitoring.
Cap construction will involve removing existing non-engineered fill down to the existing concrete
floor in each reservoir. Gravel will be placed directly on top of the existing concrete floor in each
reservoir to a height of 1.5 feet above each reservoir’s historical (1990 to 2005) high water table
elevation. The gravel will be covered with a layer of geotextile and a combination of common
earth fill and topsoil to create the finished surface. The cap will be graded to encourage runoff,
thereby minimizing water infiltration into the gravel reservoir.
This approach requires removal of the existing wetlands. Mitigation for these impacts will be
outlined in further detail in the Restoration Plan.
Specific ICs and ECs will depend partially on the degree of public access, but are expected to
include that which is summarized in Table 1 to ensure that access to the site is controlled. Long-
term monitoring will include periodic inspections and maintenance (as needed) to ensure that the
ICs and cap remain effective.
3.3 OU #3- RESERVOIR 4 (EAST DEVELOPMENT AREA)
OU #3 includes approximately 30 acres in the eastern part of the site (Figure 14) and is also zoned
for possible future commercial development (Figure 7, Figure 8, and Figure 10). This operable
unit includes Reservoir 4, several surface expressions of sticky (“purple-type”) hydrocarbon that
collectively cover an area of about 2.3 acres, and the former recycling center. The floor of former
Reservoir 4 is covered with 5 to 6 feet of non-engineered, hydrocarbon-impacted soil and
construction debris. The Risk Management Summary (BBL Sciences [BBL], 2005) recommended
that soil within Reservoir 4 be left in place with no further action, assuming that the area remains
as open space. Due to the entrapment hazard posed by the sticky hydrocarbon surface expressions,
however, these areas, together with some proximal “blue”- and “green”-type expressions that are
not physical hazards, were identified by the ERWG for remediation. OU #3 contains several small
areas of wetlands and rare plant communities, which will be described in the Restoration Plan.
The ERWG also determined in 2005 that the former recycling center does not currently provide
suitable ecological habitat because it is paved and may be developed in the future. As such, the
Risk Management Summary concluded that no further remedial action was necessary as long as
the area does not revert to open space.
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For purposes of the FS evaluation, the development scenario was defined as including all of the
activities necessary to leave the operable unit in a condition such that a developer could undertake
construction. For OU #3, this is potentially significant since there are several feet of non-
engineered fill within Reservoir 4 anticipated to be incapable of supporting a conventional spread
footing building foundation without adverse differential settlement. Consequently, the FS
considered remedial alternatives that would support high foundation loads by removing and
replacing the non-engineered, hydrocarbon-impacted fill within Reservoir 4, as well as
development alternatives that would require minimal structural support, such as a parking lot.
Weathered, high-molecular weight TPH-impacted soil extends to depths of up to 50 feet below
Reservoir 4 (Figure 12). As no significant risk has been attributed to the presence of this material,
and considering the impracticability of contaminant removal, remedial measures targeting this
material were not considered in the FS.
Subsequent to the FS, a refinement of the land uses shown in the AASP has been proposed.
Consequently, the grading of the original preferred alternative was augmented to support this land
use concept. The approach is at least equally effective, in that surficial hydrocarbon exposures are
removed. In addition, the refined preferred alternative provides a soil cover over Reservoir 4 that
is at least 4 feet thick, and as much as 11-feet thick. The cover will provide a barrier between the
impacted soil and potential receptors and also sufficient structural support for future onsite
construction. A geotextile identifying layer, placed between the cap and the existing ground
surface, would serve to reduce the likelihood of inadvertently excavating into the impacted soils.
Landscaped areas of the cover would be planted with appropriate shallow-rooted vegetation to
prevent erosion without penetrating the cover as part of ICs.
Construction will unavoidably impact wetlands, VPFS habitat, and rare plant communities, which
will require mitigation. Details of impacts and proposed mitigation will be provided in the
Restoration Plan.
Since residual contamination will remain at depth, ICs and ECs will be used to minimize the
potential for future onsite exposures. Proposed ICs and ECs are summarized in Table 1. Long-
term monitoring will be used to assess compliance and effectiveness of the ICs and ECs.
3.4 OU #4- REMAINING SITE-WIDE TERRESTRIAL AND WATERS/WETLANDS AREAS
OU #4 includes all the remaining terrestrial and waters/wetlands areas of the Tank Farm not
considered in the first three OUs. OU #4 covers an area of about 270 acres, all but 24 acres of
which is planned open space. Three AOCs were defined in the operable unit corresponding to
“must-do” areas identified by the SERRT (Figure 14). These are:
• AOC#1 – North Marsh (including a portion of Tank Farm Creek) Complex
• AOC#2 – Reservoir 3
• AOC#3 – Other sticky hydrocarbon surface expressions.
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All three of these areas were identified by the SERRT due to the presence of sticky hydrocarbon
surface expressions. However, the conditions surrounding the occurrence of these surface
expressions in each area of concern are subtly different, necessitating separate consideration. A
large amount of wetlands occur in OU #4, including areas identified as VPFS habitat. Details of
existing wetland delineation and VPFS habitat will be discussed in the Restoration Plan. The OU
also includes substantial coverage by a variety of rare plant communities.
The Risk Management Summary also recommended two areas of surface hydrocarbon expressions
surrounding Reservoir 3, which were not identified as eco-risks, for ripping to facilitate
revegetation. However, ripping will be avoided in these two areas because ripping operations
would impact currently occupied VPFS habitat.
3.4.1 AOC #1 - North Marsh Complex
AOC# 1, the North Marsh complex, consists of waters/wetlands located east of the Northwest
Operations Area. The waters/wetlands include the most extensive coverage of pliable plastic (i.e.,
“blue” and “purple”) hydrocarbon surface expressions at the Tank Farm. When grouped into areas
based on proximity, these expressions cover about 7 acres. The extent in the shallow subsurface
soils, however, may be significantly larger. Based on the 1926 topography of the North Marsh
complex, these surface expressions may cover as many as 13 acres. The thickness of the
expressions varies but has been estimated to be 2 to 3 feet on average. Surveys of the North Marsh
complex have not identified VPFS habitat.
The preferred remedy is to excavate the plastic hydrocarbon surface expressions from the North
Marsh complex, dispose of the impacted material offsite, and restore (reestablish and rehabilitate)
remaining waters/wetlands areas. The area of excavation is estimated to be between 7 and 13 acres,
with an average assumed excavation depth of 3.5 feet. Given the areas and thickness, the
excavation may generate anywhere from 40,000 to 73,000 cubic yards of material. Any excavated
material suitable for reuse as specified in an agency-approved Soil Management Plan would be
stockpiled separately and used later as backfill for remediation or restoration activities. It is
anticipated that the soil would be disposed of as nonhazardous impacted soil at the Santa Maria
Landfill or another appropriate landfill. Depending on the feasibility and landfill used, trucks may
haul clean material from the landfill on their return trip to be used as backfill material for the North
Marsh complex. It is assumed that the upper 1 foot of backfill material would be comprised of an
appropriate organic-rich topsoil, to be specified in the Restoration Plan, consisting either of clean
soil from on site or imported to the site. The actual amount of topsoil required would be based on
the final soil balances from remedial and restoration grading operations. For the purposes of this
analysis, it is assumed that 1 foot of topsoil will need to be imported for backfilling and restoration.
Once the excavation, backfill, and final grading operations are complete, the North Marsh complex
would be replanted to restore and improve waters/wetlands function and will be described in the
Restoration Plan. Proposed ICs and ECs are summarized in Table 1. Long-term monitoring would
include a monitoring and maintenance program to ensure that those controls remain effective.
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3.4.2 AOC #2 - Reservoir 3
AOC #2 includes 8.4 acres within the footprint of former Reservoir 3. Much of the ground surface
within the former reservoir area is covered by pliable hydrocarbon surface expressions with
entrapment hazard potential. Studies have demonstrated that groundwater is not responsible for
the hydrocarbon surface expressions in this former reservoir. These studies have determined that
viscous oil is being slowly squeezed from the mixed reservoir fill as the soil slowly settles. The
reservoir is filled with 8 to 11 feet of non-engineered fill, including berm soils, construction debris,
and tar. A large portion of Reservoir 3 consists of precipitation/runoff-supported wetlands that are
occupied by VPFS, which will be described in the Restoration Plan.
The preferred remedy consists of constructing a soil cap with an impermeable geosynthetic liner
that will establish a permanent barrier between contaminated soil and potential human and eco-
receptors at the surface. The cap will attempt to reestablish wetlands in the same area and will be
described in the Restoration Plan. This was determined to be an acceptable approach due to the
fact that historical groundwater elevations suggest that Reservoir 3 is not fed by groundwater.
Conceptually, the cap will be constructed by removing a minimum amount of hydrocarbon-
impacted soil so that the cap can be installed without significantly changing the existing grades.
Non-hazardous Hydrocarbon Impacted (NHIS) soil will be disposed of at an appropriate landfill.
Since the remaining reservoir fill material is non-engineered and, at best, has poor bearing
capacity, it will be necessary to support the cap with various soil and geosynthetic materials. A
geotextile will be laid over the exposed work surface and anchored in a trench excavated around
the perimeter of the work area. A tri-directional geogrid anchored in a 1-foot-thick gravel layer
will be used to distribute loads as evenly as possible and to limit settlement to the cap center. A
flexible membrane liner protected above and below by geotextiles will create the impermeable
barrier. The primary function of the flexible membrane is to prevent downward migration of water,
which may help to support wetland habitat in a manner similar to the current condition. The final
component of the cap will be an overlying thickness of common fill and organic-rich topsoil, which
will be contoured to mimic the existing topography and wetland hydrology.
Remediation will unavoidably impact wetlands, which has also been identified as VPFS habitat,
and rare plant communities. Details of wetland, VPFS habitat, and rare plant community impacts
and their associated mitigation will be described in the Restoration Plan. Proposed ICs and ECs
for Reservoir 3 are summarized in Table 1 and are designed to ensure that access to the site is
limited and controlled. Long-term monitoring will include periodic inspections and maintenance
(as needed) to ensure that the institutional controls and cap remain effective.
3.4.3 AOC #3 - Pliable Surface Expressions of Petroleum
AOC #3 includes approximately 3 acres of sticky hydrocarbon surface expressions in six general
areas of the south Tank Farm (Figure 14). These surface expressions occur in topographically low
areas that accumulated petroleum during the 1926 fire. These expressions are limited in areal
extent by surrounding berms and are 2 to 3 feet thick on average. Because these expressions are
in topographically low spots, many occur within waters/wetlands, some of which include VPFS
habitat.
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The preferred remedy consists of excavating the plastic hydrocarbon surface expressions,
disposing of the impacted material offsite, and restoring the original grade. This alternative would
also restore (at a minimum) the existing waters/wetlands functions, establish ICs and ECs, and
provide long-term monitoring. It is anticipated that the initial restoration of the impacted wetlands
will occur at their current locations, but the final locations will be provided in the Restoration Plan.
Wetland, habitat, and plant mitigation details will be described in the agency-approved Restoration
Plan.
Proposed ICs and ECs for AOC #3 are summarized in Table 1 and are designed to limit and control
access. Long-term monitoring will include periodic inspections to ensure that those controls
remain effective.
3.4.4 AOC #4 – Arsenic
AOC #4 includes approximately 0.8 acre of arsenic-impacted shallow soil northeast of Reservoir 2
(Figure 14). The impacted soil has been identified to be limited to the upper 2 feet of soil
(Appendix K). This area supports wetlands, VPFS habit, and rare plant communities.
The preferred remedy consists of excavating the upper 1 to 3 feet of soil within the delineated area
and restoring the original grade. The excavated arsenic-impacted material will either be used as
backfill material within the Northwest Operations Area beneath the proposed cap or disposed of
offsite. Restoration, creation, or reestablishment of waters/wetlands impacted by remedial actions
will be described in the Restoration Plan.
3.5 OU #5- SITE-WIDE GROUNDWATER
OU #5 includes site-wide groundwater, exclusive of the Northwest Operations Area. Groundwater
flows toward the southwest at an average rate of about 100 feet per year. It travels primarily within
sandy interbeds in the largely fine-grained valley fill. The major potential source areas for
petroleum impacts to water quality in OU #5 are the LNAPL areas underlying the former
reservoirs.
Groundwater monitoring of OU#5 has been conducted continuously since 1990, both on and off
the property, through a network of monitoring wells. The entire network is comprised of more
than 80 monitoring wells. However, sufficient data has been collected during the 24-year program
that the RWQCB has approved actively monitoring 29 of these wells. The 29 wells are located in
key positions around the site that ensure any changes in the groundwater conditions could be
rapidly addressed.
Almost 1,000 groundwater samples were collected from the entire monitoring network from 1990
to 2007. For the most part, these samples were tested for TEPH and BTEX, although a significant
number were also tested for PAHs. With respect to TPH, there is no maximum contaminant level
(MCL); the RWQCB regulates this contaminant on a case-by-case basis but often ascribes 1,000
micrograms per liter (µg/L) as a reasonable action level. A study of the OU #5 monitoring record
indicates that 43 percent (414) of the samples tested for TEPH contained detectable (>100 µg/L)
concentrations. These concentrations range from 100 to 1,600 µg/L, with a median concentration
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of 220 µg/L. The vast majority of detected concentrations are in the 100 to 400 µg/L range, with
many fewer in the 400 to 1,000 µg/L. Only 2 out of the 966 samples tested for TPH have contained
concentrations greater than 1,000 µg/L, and neither of these was verified by resampling. Benzene
has never been detected (<0.5 µg/L) in an OU #5 monitoring well.
Therefore, in OU #5 there is no direct evidence of offsite migration of dissolved contaminants in
excess of MCLs or the frequently applied RWQCB TPH action level of 1,000 µg/L. These
findings, together with those of the groundwater natural attenuation monitoring program, suggest
that any dissolved hydrocarbons generated in OU #5 are being attenuated by natural processes
within distances of a few hundred feet from the source.
As such, the preferred remedial alternative for OU #5 is monitored natural attenuation with ICs
and long-term monitoring. Monitored natural attenuation includes semiannual sampling of the
existing groundwater monitoring network on and surrounding OU #5, testing those samples for
TEPH and natural attenuation parameters, and reporting these findings to the RWQCB in
accordance with an approved monitoring and reporting program.
Proposed ICs and ECs for OU #5 are summarized in Table 1. Land use restrictions may also be
required on the Betita Property, situated south of the Tank Farm, due to the localized presence of
petroleum in the subsurface (Figure 13).
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4.0 GENERAL REMEDIAL ACTIONS
Sections 4 through 7 provide detailed descriptions of the proposed remedial design. This section
focuses on the general remedial actions. That is, those actions applicable across the site,
irrespective of the operable unit. This includes long-term monitoring, excavation, and the general
approach used in capping.
Remedial actions implemented through this plan will be performed in accordance with the
mitigation measures in the certified FEIR (Marine Research Specialists, December 2013) and other
relevant regulations. The mitigation measures relevant to the remedial actions will be included as
Conditions of Approval in the permits issued by jurisdictional agencies. A Conditional Use Permit
with associated Conditions of Approval was issued by the County of San Luis Obispo Planning
Commission on October 23, 2014.
Another County agency, the SLOAPCD, will issue an Authority to Construct and Permit to
Operate with Conditions of Approval. These conditions will include submittal of supplemental
plans (Dust Control Plan, Hydrocarbon-Affected Soil Management Plan, Construction Activity
Management Plan, Blasting Plan, Asbestos Dust Control Plan, etc.) with requirements guiding the
conduct of work by the remedial contractor.
Other agencies with permit authority for aspects of the project include, but are not limited to, the
U.S. Army Corps of Engineers, USFWS, National Marine Fisheries Service, and CDFW.
4.1 LONG-TERM MONITORING
As described in the FS, remedial action includes various long-term monitoring activities. The
principal monitoring activity is groundwater sampling and reporting. The requirements of the
current program are described in Monitoring and Reporting Program (MRP) 93-120, which is
provided in Appendix B along with supporting documentation describing its evolution over the
last 15 years. The monitoring program currently requires sampling of onsite and offsite wells
according to the list provided in Table 2. As part of the remedial activities at the site, the MRP
will be updated to include monitoring of the integrity of the remedial caps, including the frequency
of monitoring and specific activities involved during the monitoring events.
Chevron currently samples all of the wells listed on a semiannual basis. Samples are tested for
extractable range hydrocarbons, and samples from wells monitoring OU #1 are also tested for
purgeable range hydrocarbons and BTEX. A few samples are analyzed for all three constituent
types.
Eleven monitoring wells, including 4 that are currently monitored (Table 2), are located in
remediation areas and will need to be abandoned as part of the overall remediation activities
(Figure 20). Replacement of wells needed for post-remediation monitoring will be determined in
consultation with the RWQCB.
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Another consideration for future MRP revisions will be reductions in the monitoring frequency if
post-remediation monitoring indicates that remedial objectives were achieved. Proposed post-
remediation monitoring details are discussed more thoroughly in Sections 7.1.1 and 7.5.
Long-term monitoring will also include periodic inspections of the caps and excavation areas to
ensure those remedies continue to function properly and are achieving the remedial action
objectives. Semiannual inspections are proposed, with one inspection event just prior to the rainy
season and the other during or just after the rainy season.
4.2 REMOVAL EXCAVATIONS
Some impacted near-surface soils, mostly those affected by petroleum with wildlife entrapment
potential, will be removed. These removal areas have been chosen to either improve the function
of a capping system or to mitigate an identified ecological risk. Where performed in conjunction
with construction of a cap, the excavation will remove a limited amount of material defined by an
excavation depth (e.g., 2 feet) or by exposure of some existing feature (e.g., a former reservoir
bottom).
Removal areas are described further in Sections 7.4.1 and 7.4.3, the North Marsh complex and
Other Sticky Hydrocarbon Surface Expression areas of concern, respectively. The remediation by
removal approach will be limited to pliable hydrocarbon material as originally identified in the FS.
Field surveys will be conducted during construction activities to determine if new pliable
hydrocarbon material has surfaced since the conclusion of the FS. Field determinations may also
occasionally be required in consultation with the appropriate regulatory agencies to determine the
need for removal of some hydrocarbon materials. Field determinations will be based on visual
inspections for indications of recent hydrocarbon material flow or existing material expansion.
Areas of expansion will be documented on field forms, and Global Positioning System (GPS)
locations and photos will be recorded prior to removal and disposal of the material.
Field investigations have shown that the isolated pockets of plastic hydrocarbon identified for
removal are the byproducts of the 1926 fire or operational spills and appear to be localized to
within 3 to 4 feet of the ground surface. In the event that these impacts are determined to extend
locally to depths greater than 5 feet, it is proposed that removal excavations will be limited to a
depth of 5 feet bgs. Four issues were evaluated in adapting this limitation: worker safety, the
potential to encounter groundwater, mitigating risk to burrowing animals, and ensuring that plastic
hydrocarbon does not resurface at some later date.
Excavations beyond 5 feet require special planning and support for worker safety, based on the
requirements of the U.S. Occupational Safety and Health Administration (OSHA) and the
California Division of Occupational Safety and Health (Cal/OSHA). In addition, excavations
beyond 5 feet in the low-lying areas of the site are likely to encounter groundwater. The FS
demonstrated that the risks of further environmental impact and the expense associated with the
handling and treatment of impacted groundwater did not warrant the effort.
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One objective of the remedial design is to ensure that future open space uses of the site do not pose
an unacceptable risk to potential ecological receptors, which includes burrowing animals. The
proposed limit for excavation is below the burrowing depths of most animals that are likely to be
encountered at the Tank Farm (California Department of Toxic Substances Control, 1998). Further
protection may be provided by using a 0.75-inch gravel for the first 6 inches of backfill to act as a
barrier to burrowing animals, if that is deemed necessary. Such measures will be provided in
consultation with the CDFW.
Based on previous expert experience, it is expected that 5 feet of compacted backfill will prevent
resurfacing of the plastic materials. The materials are viscous and generally appear to mobilize
only when exposed to the warming effects of direct sunlight (England Geosystem, Inc., 2000). By
removing material from the near-surface and replacing it with a well-compacted backfill, the
likelihood that the material will resurface is very low. Soil used for backfill will be compacted to
90 percent of its relative maximum density as determined by ASTM International (ASTM) Method
D1557. Remediation will include long-term monitoring and maintenance of the site. In the
unlikely event that plastic hydrocarbon were to resurface, it will be detected by the long-term
monitoring program and further remedial steps, in coordination with appropriate agencies, would
be taken as part of site maintenance.
Excavated materials suitable for reuse (e.g., those not impacted by plastic hydrocarbon) will be
segregated during excavation, stockpiled locally, and reused as common earth backfill. Common
earth may include solid asphaltic (e.g., green-type) hydrocarbon. Materials that are impacted by
plastic hydrocarbon will be disposed of offsite at an appropriate location. If feasible, impacted
soils will be loaded directly onto a truck and hauled offsite. An alternative will be to temporarily
stockpile the impacted material onsite. The Northwest Operations Area or another approved
location will be used as a staging area, if needed, to stockpile contaminated soil prior to loading
on trucks for offsite disposal (Figure 15). Based on known occurrences of plastic hydrocarbon
material, it is estimated that remedial actions could generate approximately 157,000 cubic yards
of impacted soil (Appendix F). An additional 39,000 cubic yards of impacted soil was included
in the FEIR evaluation as contingency for the potential to find additional impacted soil during
construction activities.
If necessary, a secondary stockpile could be located on the south side of the Tank Farm in an
approved location, most likely adjacent to the gate on the existing paved slab (Figure 15). This
area is planned for storage of equipment and materials.
Access routes to the proposed Northwest Operations Area stockpile location are shown in
Figure 17. The routes have been chosen to use existing roads and thereby avoid sensitive habitat.
These routes may require widening and drainage improvement, as discussed in Section 6.1. A
temporary signal, flagman, or other means of traffic control will be provided, as necessary, at the
Tank Farm Road crossing.
In operating a stockpile for impacted soil, it will be necessary to comply with local air quality and
traffic regulations. This will likely require covering the stockpile and periodic monitoring to keep
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volatile organic compound emissions within regulatory limits. It will also be necessary to control
dust and minimize stockpiling during the rainy season.
It is anticipated that most hydrocarbon-impacted soils will be disposed of at the NHIS facility
operated by the City of Santa Maria at their landfill. Chevron will provide representative sampling
data for characterization purposes to the disposal facility to ensure that the impacted soils meet the
acceptance criteria.
4.3 CAPS
Caps will be used to separate impacted materials from potential human and ecological receptors.
They will be constructed from earthen materials, but may also include various geosynthetic
materials for additional strength or material separation. In addition, caps will support either open
space or development land uses.
A key distinction between the open space and development caps is that the former will be more
varied due to differing design objectives and individual site constraints and will include a topsoil
layer that will be used to support restoration. The development caps will be constructed of
structural fill with a minimum thickness of 4 feet and will be managed to minimize soil erosion.
To help protect against bioturbation, or excessive mixing of soils by burrowing animals or
aggressive vegetation, monitoring of the caps will be conducted on a quarterly basis. Large
burrows or tunnels that might allow water infiltration into the cap will be flagged and repaired.
Each open space cap will include a gravel layer that is primarily intended to accommodate
groundwater table fluctuations during the rainy season. The gravel will also provide a barrier to
keep burrowing or tunneling animals from reaching the contamination beneath the cap.
If excessive bioturbation continues to be a problem, adaptive management measures will be
employed. These would be presented in the periodic monitoring reports in response to an identified
problem. They might include measures such as sub-surface fencing, fumigation, and the use of
rodenticides.
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5.0 EARTH CONSTRUCTION MATERIALS
There are four principal types of earth materials used for this project: common fill, structural fill,
gravel, and topsoil. Specifications regarding composition, grain size, and other relevant
parameters are provided in Appendix E. The following sections provide more detailed information
regarding each of these principal soil materials.
5.1 COMMON FILL
Common fill will be used for the majority of nonstructural and unspecialized fill needs for the
project. It is readily generated from the available onsite soils. It may consist of silt, clay, silty
sand, silty clay, clayey sand, or clayey silt. Common fill may have a wide gradation, as shown in
Appendix E. One hundred percent of the material must pass a 1-inch screen, and up to 30 percent
may pass the No. 200 sieve. The soil must not have any organic or otherwise decomposable or
deleterious materials. Fill material generated from onsite borrow sources may contain small
amounts of naturally occurring asbestos (Appendix P). If asbestos is detected in quantities greater
than or equal to 0.25 percent, that material will be considered deleterious material and will not be
used at the surface and will be restricted to use as fill material below an approved depth.
Common fill will generally be placed in lifts between 8 and 12 inches in thickness and compacted
to within 90 percent of its relative maximum density as measured by ASTM D1557.
5.2 STRUCTURAL FILL
Structural fill is physically identical to common fill, but will be used in areas where greater soil
strength is required, such as the caps that may support future development. The main difference
between common fill and structural fill is that it must be placed in lifts with a maximum thickness
of 8 inches and must be compacted to 95 percent of its relative maximum density per ASTM
D1557.
5.3 GRAVEL
Gravel will be primarily used during this remediation project in the caps that will be constructed
over Reservoirs 5 and 7. The gravel will provide a structural void space that will provide a low-
resistance accumulation space for rising groundwater and LNAPL. Gravel may also be used as a
bio-barrier (if needed) in excavations or shallow caps to prevent burrowing animals from exposing
or reaching contaminated materials.
Material used for this function must be hard, durable, and not susceptible to slaking when
immersed in water. An acceptable gradation envelope is provided in Appendix E. One hundred
percent of the material must pass a 0.75-inch sieve and no less than 75 percent must be retained
on a No. 4 sieve. Further, no more than 5 percent of the soil may pass a No. 200 sieve.
The gravel may be placed in lifts of up to 12 inches in thickness and compacted with two passes
of a 5,000-pound drum roller or similar piece of equipment.
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5.4 TOPSOIL
Topsoil will be needed in restoration areas to revegetate the surfaces of caps and backfilled
excavations. Topsoil layers will typically be 1-foot-thick organic-rich soils harvested onsite,
amended, or imported to meet the specifications. Specifics of topsoil collection, handling, and
storage will be discussed in the Restoration Plan.
Topsoil can be any combination of silt-based or clay-based soil found onsite or locally. Onsite
topsoil sources will be expected to contain at least 10 percent organic material. Onsite soils not
meeting this requirement can be amended by the addition of fertilizers and mulch. Amended soils,
however, must contain at least 15 percent organic matter.
Topsoil will be placed in lifts no greater than 12 inches thick. It is anticipated that topsoil may be
nominally compacted during placement, but will be scarified to a depth of at least 4 inches prior
to seeding or planting.
Additional soil requirements will be specified in the Restoration Plan if needed to achieve the
performance measures required for each habitat area. The suitability of topsoil relative to site
contaminants (e.g., TPH, arsenic) will be evaluated per soil sampling and testing protocols. The
protocols will use site-specific risk-based screening levels and programs for sampling both in-situ
and in stockpiles. The protocols will be included in the Soil Management Plan and submitted to
the RWQCB for approval in consultation with San Luis Obispo County Environmental Health
Services.
5.5 EARTH MATERIAL SOURCES
As many of the soil materials needed for remediation will be obtained onsite as feasible. The
following sections discuss the various proposed borrow sources, the types of materials available
in each, and the estimated quantity of potential borrow material. Figure 16 shows the location of
each of the borrow sources, and Table 3 summarizes the estimated material quantities available
from each. A discussion of proposed access routes is provided in Section 6.1.
A quick comparison of Table 3 with the soil material needs of Table 4 shows that there is ample
onsite soil for most of the project requirements. Numerous borrow sources are identified, to
minimize the need to import soil, to allow flexibility, given the many construction constraints, and
to maximize restoration opportunities. For instance, Borrow Sites No. 1 and No. 2 are located
adjacent to large existing wetland complexes, providing an opportunity to expand those
complexes.
Some borrow materials, especially the tank berms, may contain asphaltic materials that are
inseparably embedded into the soil matrix. SERRT determined that the asphaltic material does
not warrant remediation and its use for common and structural fills is consistent with the findings
and recommendations of the FS. Any plastic hydrocarbon encountered during borrow operations
will be removed and disposed.
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It is estimated that 65,700 cubic yards of topsoil (Table 4) will be required for remedial
construction. Any topsoil deficit will need to be closed by manufacturing topsoil from other
borrow materials or importing topsoil from offsite sources.
Use of the borrow sites may result in habitat impacts, which will be discussed in detail in the
Restoration Plan. Final impacts will be determined during field activities and restoration of these
areas will be further defined in the final Restoration Plan.
5.5.1 Flower Mound/OU #3
In order to provide onsite materials for remediation as well as to facilitate the City of San Luis
Obispo’s proposed extension of Santa Fe Road, borrow activities at the Flower Mound/OU #3
Area will generate as much as 350,000 cubic yards of material, with approximately 40 percent that
must be blasted and processed to use. A Blasting Plan will be prepared to guide the contractor in
execution of the work. The Blasting Plan will include an asbestos dust mitigation plan and an air
monitoring program plan to verify mitigation measures are being implemented properly and air
quality is within acceptable limits. Pursuant to Airborne Toxic Control Measure Section 93105(g),
an air monitoring plan for asbestos will be submitted to the SLO APCD for approval. Other
supplemental plans will be submitted as required to execute this project. Approximately
73,700 cubic yards are located on adjacent properties, which will require access agreements with
each property owner. For planning purposes, it is assumed that at least 26,300 cubic yards, and
potentially all, of the offsite material may be available.
Material produced from the Flower Mound will be crushed and screened to the material
specifications included in Appendix E. It is anticipated that the Flower Mound material will be
readily suitable for use as common, structural fill, or road base. However, preliminary testing
(Padre, 2007a) suggests that the Flower Mound material may not be sufficiently durable for use as
gravel in the caps that will be constructed over Reservoirs 5 and 7 (Section 7.2).
For the processing of the material from the Flower Mound potentially containing naturally
occurring asbestos, Chevron will comply with District Rules and Regulations, and Air Toxic
Control Measures 93105, Asbestos Airborne Toxic Control Measure for Construction, Grading,
Quarrying, and Surface Mining Operations, and 93106, Asbestos Airborne Toxic Control Measure
for Surfacing Applications. Chevron will work collaboratively with the SLOAPCD to develop a
plan with sampling criteria and frequency to determine the asbestos content of any aggregate
material to be used as surfacing material from the Flower Mound. The sampling criteria and
frequency will be submitted with the Authority to Construct application for the project for review
and approval by the SLOAPCD.
5.5.2 Berms
It is proposed to use the berms adjacent to Reservoirs 5 and 7 to supply the common fill required
for cap construction. If borrow from the berms is maximized, approximately 71,600 cubic yards
will be generated; 38,800 cubic yards at the Reservoir 5 site, and another 32,800 cubic yards at
Reservoir 7. Construction of both caps requires 37,000 cubic yards, which will result in
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approximately 34,600 cubic yards of excess material that can be used for other onsite common or
structural fill needs.
5.5.3 Borrow No. 1
Borrow No. 1 is an approximately 8.6-acre site located adjacent to the North Marsh (Figure 16).
It includes approximately 2.3 acres that may have been used as a disposal area for demolition
debris from the 1926 fire. Anecdotal reports suggest that the disposed materials consist mostly of
construction debris, such as concrete and wood. It is estimated that the disposal area contains
approximately 10,300 cubic yards, assuming an average depth of approximately 4 feet. As
described in Section 7.4.1, this material will be characterized, removed, and managed at an
appropriately permitted facility.
After removal of the debris, it is anticipated that further excavation will be done to expand the
wetland and borrow soil for onsite use. Soil suitable for use as common and structural fill, and
possibly as topsoil, could be removed from the borrow area. The nominal grading contours for
this area would begin at the existing floor of the wetland area and slope back to the east at
approximately 0.5 percent. Side slopes would be no greater than 4:1 (horizontal:vertical). This
grading approach would generate approximately 27,200 cubic yards of common or structural fill.
It is estimated that approximately 9,000 cubic yards of topsoil may be recovered from this borrow
area as well. Complete utilization of the borrow source and removal of the historical debris would
potentially generate additional wetland habitat. Final activities in this area will be determined in
consultation with resource agencies and will be addressed in the final Restoration Plan.
5.5.4 Borrow No. 2
Borrow No. 2 is located on the east portion of the site, south of Tank Farm Road (Figure 16). It
covers approximately 17.73 acres. This location is anticipated to provide topsoil for revegetation
purposes.
It is estimated that at least 20,700 cubic yards of topsoil may be recovered from this location. It is
assumed that the topsoil horizon is 2 feet thick, although the Geotechnical Report (Padre, 2007a)
suggests that as much as 4 feet of suitable material may be available. After borrow operations are
completed, the site will be regraded as shown in Figure 39. Excavation and restoration of Borrow
No. 2 will temporarily or permanently impact existing waters/wetlands, VPFS habitat, and
sensitive plant communities. Details of impacts to these ecological resources and their associated
mitigation will be discussed in the Restoration Plan.
5.5.5 Borrow No. 3
Borrow No. 3 has a similar function to Borrow No. 1. It provides a useful source for common fill
and structural fill, and possibly topsoil. It also provides an opportunity to expand the adjacent
wetland, which will be discussed in the Restoration Plan.
The proposed area is approximately 13.5 acres in extent (Figure 16). It is assumed that material
will be borrowed from this source starting at the wetland along the south boundary. The existing
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grade would be lowered to the elevation in the southwest corner and then allowed to slope up at
approximately 0.5 percent to the north. This approach will yield approximately 50,650 cubic yards
of total borrow (16,900 cubic yards of top soil and 33,750 cubic yards of common earth), and could
generate new wetland habitat if fully utilized. Final ecological impacts will be determined during
field activities, and restoration of these areas will be further defined in the final Restoration Plan.
5.5.6 Oxbow Borrow
The oxbow borrow provides a source for common fill as well as rich topsoil that may be used for
restoration throughout the site. This borrow area, similar to Borrow No. 3, provides an opportunity
to expand the oxbow channel system to allow for the creation of additional wetlands and increase
functionality of the existing system.
The proposed borrow area is approximately 1.75 acres in extent. Borrow will be taken from this
area to an average depth of approximately 10 feet to establish a functioning wetland within the
confines of the oxbow and will be discussed in the Restoration Plan. This approach will generate
approximately 25,500 cubic yards of common earth and 2,800 cubic yards of topsoil material.
Final restoration of this area will be further discussed in the Restoration Plan.
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6.0 SITE-WIDE REMEDIAL ACTIONS
There are several construction-related remedial actions that are not considered specific to a
particular OU. Those actions are discussed in this section and include mobilization and staging of
equipment and materials, demolition of the existing buildings, miscellaneous cleanup activities,
and abandonment of the remaining pipelines.
6.1 MOBILIZATION, STAGING AREAS, AND SITE ACCESS
Mobilization is the stage of construction when the contractor prepares the site to begin work. This
includes a variety of tasks including moving equipment and support trailers onsite, improving site
access, installing storm water and dust control Best Management Practices (BMPs), and natural
resource protection measures. To successfully accomplish this work, the contractor will require
ready access to the work areas with logical and ample traffic routes. At the same time, the
contractor must also minimize impacts to non-work areas and avoid sensitive habitat areas that
must be preserved. Figure 17 shows the anticipated work areas and the proposed staging areas and
access routes. Within the scope of the activities described in this Revised RAP, the contractor will
limit his activities to the areas identified in Figure 17. In the event unforeseen site conditions
require access to the off-limit areas, access shall be coordinated on an as-needed basis with the
appropriate regulatory authorities.
The work areas are the limits within which remediation activities will be conducted for a given
operable unit or area of concern. The work area limit is generally defined by the extent to which
a particular site must be cleared and grubbed to properly perform the work and provide the
contractor with sufficient room to move equipment and materials. The limits shown in Figure 17
are, however, only approximate. More precise delineations of the work areas are provided in the
drawings found in Appendix C, and these areas will continue to be refined as the project
progresses.
The contractor will use the former recycling area as his primary staging area. It is paved, readily
supplied with electrical power and telephone service, and is centrally located on the property with
reasonably convenient access across Tank Farm Road. Major maintenance (e.g., engine rebuilds,
fluid changes, fueling) may be performed at the primary staging area in specially prepared areas
with proper spill control measures in place.
Other local staging areas are also shown in Figure 17. These are located directly adjacent to the
work areas and would be used to stage materials, park equipment, and other support activities.
Vehicles and equipment can be fueled and minor maintenance (e.g., changing tires) may be
performed at the local staging areas.
Water is available onsite for construction purposes. Water wells are located just north of the
Northwest Operations Area, at the southwest corner of the site (south of Tank Farm Road), at the
southernmost tip of the site (also south of Tank Farm Road), and on the eastern edge of the site
south of Tank Farm Road (Figure 17). The contractor will supply pumps (as necessary), storage
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tanks, and stands to fill water trucks. One storage tank and fill stand is expected be in the primary
staging area (Figure 17), and another will likely be located south of Tank Farm Road, adjacent to
the entrance. The final locations will be determined by the contractor to best facilitate his work,
consistent with the work area constraints show in Figure 17. The contractor is responsible for
determining the adequacy of water supply and for making any upgrades to the supply
infrastructure. Prior to mobilization, the suitability of the existing water distribution network for
conveying water for construction purposes will be evaluated. If feasible, fill stations would be
located at readily accessible points such as the fire hydrants. Otherwise fill stations will be
supplied by temporary overland pipelines. At this time, it is expected that the southernmost well
will be the primary source of construction water at the site and that aboveground irrigation-grade
piping will be used for water conveyance to aboveground water holding tanks supplied with J-
stands.
Bottled water will be used for potable purposes and will be brought onsite and stationed at work
and staging areas as needed. The contractor will also supply sanitary facilities at needed locations.
The principal construction entrance to the site is anticipated to be located as shown in Figure 17.
This location utilizes the existing entrance to the site south of Tank Farm Road, but is also
reasonably close to the Primary Staging Area. It also consolidates access to the site at one point
along Tank Farm Road. A traffic study (Associated Transportation Engineer, 2007) recommended
a standard intersection with left-hand turn pockets and right-hand deceleration lanes at the site
entrance. The intersection should also include signalization to control traffic during the
construction period. A preliminary traffic control plan is shown in Figure 18. The plan will be
finalized with the SLO County Public Works Department. The conceptual plan moves the entrance
gate back approximately 100 feet from the road. Berms will also be removed to provide
deceleration lanes and to ensure adequate site distance. The greater distance from the road will
allow trucks to park at the gate without blocking traffic along Tank Farm Road. Other access
points will be provided as needed but controlled by the contractor. Access to the site will also be
maintained at the Northwest Operations Area, but will not be used as a primary access to the site.
The internal routes shown in Figure 17 are intended to provide the contractor with access to all
potential work and borrow areas across the site with as little impact to sensitive habitat as possible.
The access routes utilize existing dirt tracks. Those shown as solid lines in Figure 17 will be
required, while those shown as dashes will only be used if the borrow sources shown at the end of
those routes are developed. It is anticipated that most routes must be able to accommodate two-
way traffic. Existing dirt tracks will be widened, as necessary, to at least 24 feet in the direction
that is least likely to affect adjoining sensitive areas and habitats. Management procedures will be
used to minimize impacts from dust and erosion. Where necessary, the contractor will improve
the roadway by grooming the subgrade to provide a reasonably smooth and regular surface. In
areas potentially subject to inundation or rutting a geotextile will be placed over the subgrade and
will be used to provide separation between the subgrade and a 6-inch-thick (minimum) course of
compacted crushed miscellaneous base or gravel.
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The contractor will also provide traffic control to ensure the safe operation of vehicles and
equipment. One key component will be controlling traffic crossing Tank Farm Road. It is
anticipated that a temporary traffic signal will be used, but at a minimum the contractor will
provide a flagman and signs.
The contractor may suggest alternative access points onto and across the Tank Farm. Any
alternative routes must be approved by the Construction Manager and the appropriate regulatory
agencies prior to use. Access to the borrow areas will be provided on an as-needed basis. As noted
previously, some of the borrow sources may be used to facilitate other project needs such as
mitigating impacts to natural resources. The use of these locations, and the associated access
routes, will be determined at a later date.
6.2 BUILDING DEMOLITION
There are four buildings at the Tank Farm (Figure 3), located in the Northwest Operations Area,
that will be demolished during remediation. Three of these buildings were constructed to support
historical operations at the site. Two of these buildings have undergone asbestos and lead paint
abatement and are no longer used, and the third is used primarily as office space. The fourth, a
modular building installed adjacent to the northernmost original building, was constructed within
the last five years to provide additional office space. Chevron personnel and operations will be
removed from the site in conjunction with remediation; however, it is possible that building
demolition could precede implementation of the final RAP.
Before, or as the buildings are demolished, recyclable or potentially reusable materials will be
removed. It is anticipated that the buildings will be demolished using excavators. Some of the
buildings have metal structural elements or siding, which will be segregated for recycling as
feasible. Other materials will be loaded into haul trucks for disposal. Concrete foundations will
be broken apart using a hydraulic hammer and removed. It is possible that concrete will be crushed
and used as gravel elsewhere on the site.
Utility lines will be disconnected and abandoned. Where lines are aboveground, they will be
removed. Where utility service is brought to a building underground, the line will be cut at a point
at least 2 feet below grade and capped. Service lines that use pipes or conduits greater than
4I inches in diameter (e.g., water, sewer) will be filled with cement grout.
Voids created in the existing grade by demolition will be backfilled with structural fill or gravel.
6.3 MISCELLANEOUS CLEANUP
There are four locations onsite that have been identified as requiring cleanup or demolition that
are not part of one of the operable units or areas of concern. They are not generally “contaminated”
or impacted areas, although they may have some impacted soil associated with them. Rather, they
are comprised of debris or abandoned structures that are unsightly or possible physical hazards.
These are shown in Figure 19.
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Three of the locations are found on the parcel north of Tank Farm Road. There are two debris
piles along the north property line. They appear to contain mostly concrete debris. As with other
concrete debris, the contractor may crush this material and reuse it for gravel elsewhere on the site.
Otherwise, the concrete shall be hauled offsite for recycling or disposal.
The other area identified on the parcel north of Tank Farm Road is the historical debris disposal
area adjacent to the North Wetland. As discussed in Section 5.5.3, the material in this area will be
excavated and removed for disposal or recycling as appropriate. It is recommended that the limits
and characteristics of the waste be defined prior to excavation and disposal. Material removed
from the excavation will be segregated on the basis of how it will be managed. Concrete may be
recycled, as described previously. Other construction debris will be sent to a solid waste landfill
for disposal. Impacted soils will be removed, characterized, and managed at an appropriately
permitted facility. It is anticipated that the excavation will not be backfilled to expand the wetland
area.
The fourth miscellaneous cleanup location is found
south of Tank Farm Road, adjacent to Reservoir 6
(Figure 19). It is a concrete vault approximately 5 feet
wide, 12 feet long, and 8 feet deep. The crude oil supply
line serving Reservoirs 6 and 7 connected to it, but it is
not known if it was a separator, a valve box, or served
some other purpose. The vault is open and presents a
physical hazard to people and animals and a possible
entrapment hazard to small animals. The steel hand rail
will be removed and the upper 3 feet of the concrete
wall will be broken and used to fill the bottom of the
vault. A sand-cement slurry will be used to fill the void
spaces. The remaining depth of the vault will be
backfilled with common fill until the original grade is
reestablished.
6.4 PIPELINE REMOVAL AND ABANDONMENT
When operational, the Tank Farm required numerous pipelines to move oil between the pump
house, boilers, tanks, and reservoirs. The site was also served by water, natural gas, and septic
lines. Figure 5 shows pipeline locations based on historical facility drawings. It is estimated that
more than 25,000 feet of oil pipeline were installed onsite; approximately 4,500 feet are found in
the Northwest Operations Area (Figure 6). Much of that pipeline remains in place, as indicated in
Figures 5 and 6. Appendix L provides an analysis supporting assumptions, lengths of each type
of pipeline, and volume of liquids in each type of pipeline.
Chevron intends to remove and dispose of most of the pipeline located within work areas or found
aboveground. Figure L-2 shows the extent of pipelines within the work areas. By abandoning in
place the pipelines that are outside of the work areas, the overall project disturbance is minimized.
In addition, many of these areas are sensitive habitats (e.g., the rings of the former aboveground
Abandoned concrete vault adjacent to
Reservoir 6-to be abandoned
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storage tanks) that do not require any other remediation. In-place abandonment in these areas
preserves existing habitat. Finally, any of the pipelines are subject to abandonment in place if
removal were to create unsafe work conditions.
All pipelines will be flushed and, if possible, pigged to remove residual hydrocarbon and vapors
prior to abandonment. If a section of pipeline is in such poor condition that it cannot be adequately
cleaned, it will be excavated and removed in its entirety. These procedures of pipeline draining
and decommissioning will be modified based upon field conditions or improved methods.
A site-wide oil spill contingency plan will be prepared and implemented for the remediation
activities to outline response procedures for releases that may occur during this or other operations
(as recommended by CDFW in its comments on the Draft Final RAP emailed on September 22,
2014 to the RWQCB staff, see Appendix N).
6.4.1 Pipeline Inventory
The positions of the pipelines shown in Figure 5 and Figure 6 have not been field verified. While
these figures (and the similar engineering drawings found in Appendix C) are reasonable
approximations of their locations, final remediation will require more accurate information. It is
expected that prior to abandonment, a detailed field survey will be performed to locate the lines
and characterize their contents. Potholes will be dug at key locations (e.g., ends, transitions,
junctions, valves) to expose the pipe and determine its diameter and materials of construction.
Line tracing will be performed using an appropriate geophysical instrument operated by a trained
technician. The alignment of the pipeline will be flagged every 5 feet. Pothole and flag locations
will be recorded using a high-precision GPS unit and entered into a Geographic Information
System (GIS ) database. A detailed pipeline inventory, noting location, depth, size, materials of
construction, and condition, will be created to guide abandonment activities.
Given the interconnected, and possibly deteriorated, web of pipelines within the Northwest
Operations Area, Chevron may elect to cut the lines at the operable unit boundary and completely
remove them from its interior. In this case, the lines will be removed in accordance with
Section 6.4.4 after their positions have been confirmed.
6.4.2 Pipeline Flushing and Pigging
Water trucks attached to portable pumps would be connected via hose to each petroleum pipeline
segment within the facility. Additionally, several portable storage tanks or vacuum trucks would
be stationed and attached to the pipelines to receive and collect the flush water. Each pipeline
segment will be flushed with an adequate volume of water to remove residual oil from the
pipelines. Pipeline flushing operations will continue until no sheen is observed in the flush water.
The pipeline segments that may be suitable for pigging will be identified by Chevron during the
initial potholing activities or other field activities. The pigging operations will be basically the
same for each pigging run segment. The maintenance tool or pipeline pig is introduced into the
line via a pig trap, which includes a launcher and receiver. Without interrupting flow, the pig is
then forced through the pipe by fluid flow, or it can be towed by another device or cable. Usually
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cylindrical or spherical, pigs sweep the line by scraping the sides of the pipeline and pushing debris
ahead. Each segment will have a beginning location where the pig is “launched,” and an end
section where the pig is “received.” The pigging operation procedures are presented below.
First, the launching/receiving locations will be prepared for the procedure. Buried ends of the
pipeline will be excavated. The excavations will vary depending on the depth of the pipe, but
should not typically exceed an area larger than 7 feet wide by 12 feet long (84 square feet) and no
more than 5 feet in depth. A trench box may be used to minimize the area affected by the
excavation.
The pipeline fluids will be drained from the pipe and the pipe will then be cold-cut to gain access
to the pipe. The pig launcher/receiver will then be attached to the exposed pipe ends.
Once the pig launcher and receiver are attached to the pipeline, the subject pipe segment will be
pigged. The pigging operation will involve the use of scraper-type or foam pigs. The scraper pig
is constructed to help remove any remaining hydrocarbons from the inside walls of the pipeline as
it moves down the pipe. The pigs will be pushed through the piping segment using liquefied
nitrogen gas or compressed air.
At the receiving end, vacuum trucks will be used to remove any liquids from the pipe as the liquids
are pushed ahead of the pigs. Carbon filtration canisters will treat any vapor emissions generated
during pipeline purging operations, in accordance with San Luis Obispo County Air Pollution
Control District (SLOAPCD) requirements. Chevron will obtain approval from SLOAPCD for
the proposed activities. Recovered hydrocarbons and water from the pigging operation will be
properly disposed of or recycled at an appropriately permitted facility.
There is the possibility that a pig may become lodged in the pipe by an obstruction. If the pig
becomes obstructed along a pipe segment, the field crews will identify these locations. Excavation
activities may be required to remove the pig and the damaged/obstructed section of pipe.
6.4.3 Pipeline Grouting
Pipelines that are scheduled for abandonment in place with diameters greater than 4 inches will be
grouted with a cement-slurry to prevent any future ground subsidence from pipe wall collapse.
Site conditions may make grouting some pipe either impractical or undesirable. If accessing the
pipe would create unsafe work conditions, increase site disturbance, impact sensitive habitat, or
the pipe has deteriorated such that the grout would leak, the pipe will be abandoned in place
without grouting. A portable grout pump will be used to pump grout into the pipeline segments.
Following grouting, the pipeline segment ends will be backfilled with soil and the soil compacted.
6.4.4 Pipeline Segment Removal
Chevron proposes to remove piping that is located within remediation work areas or is
aboveground and readily accessible. If practical, the pipeline segments will be flushed or pigged
prior to removal. The pipeline segment endpoints will be isolated and cut. The pipeline segment
will then be uncovered by excavating a trench to the existing pipeline depth. As the pipeline is
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removed from the trench, a spill containment device will be placed under the pipeline end to catch
any residual fluids in the containment. All liquids drained from the piping into the containment
device will be removed using a vacuum truck and hauled to an approved facility for disposal or
recycling. The pipe segments will then be cut into manageable pieces, the pipe ends wrapped in
plastic to prevent spillage, the segments removed from the trench, and the trench backfilled. Scrap
pipe will be temporarily stored in bins and transported offsite for recycling.
6.5 MONITORING WELL DESTRUCTION
Remediation will require the destruction of 25 monitoring wells across the site. These wells are
listed in Table 2 and shown in Figure 20. Each of the affected monitoring wells is in an area that
will be excavated or over which a cap will be constructed. Post-remediation replacement
monitoring wells will be determined in consultation with the RWQCB and incorporated into the
MRP.
Well abandonment will be performed in accordance with California Department of Water
Resources Bulletin No. 74-81 and the applicable requirements of the San Luis Obispo County
Department of Environmental Health. Permits for this activity will be obtained from the San Luis
Obispo County Department of Environmental Health. Monitoring well monuments will be
removed and disposed of offsite. The wells will be drilled out using an auger slightly larger than
the original boring. Most of the wells consist of 4-inch casing in an 8-inch boring. In this case, a
10-inch-diameter auger would be used to drill out the well. Cuttings will be stored in drums and
disposed of offsite. The boring will be backfilled with hydrated bentonite. The boring will be
checked 24 hours after the initial abandonment. Additional hydrated bentonite will be added if
settlement of the initial fill is observed.
A completion report for the abandonment of monitoring wells will be submitted to the SLO County
Department of Environmental Health as required by the destruction permits and to the RWQCB
in the MRP.
6.6 HISTORICAL WATER WELLS
Review of historical operational records and facility drawings has identified the approximate
locations of three historical water wells. These approximate locations, which have not been
verified, are shown in Figure 19. Inspection of these areas has not revealed any surface features
associated with the wells. It is likely that the wells were abandoned many years ago and any other
record of them has long since been lost.
Chevron proposes to conduct a thorough field investigation to verify the location and condition
of the wells in an attempt to determine if the wells were properly abandoned. It is probable that
the wells were constructed with steel casings, and if they are still present, they could possibly be
detected by a magnetometer. A licensed geophysical contractor will sweep the approximate well
sites and will map and stake any magnetic detections. A backhoe will be used to expose the
detections and identify them. If the wells are located, the method of abandonment will be
investigated. If the method does not meet modern standards, a Well Destruction Plan will be
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prepared and submitted to RWQCB for approval. Upon approval, permits will be obtained from
the SLO County Department of Public Health and the well will be abandoned according to the
requirements of California Department of Water Resources Bulletin 74-81.
6.7 RESERVOIR 2 BERM REMOVAL
Reservoir 2 currently consists of a 600-foot-diameter circular berm approximately 15 feet in height
and is a significant feature within the runway protection zone (RPZ) (Figure 9). The SLO County
Airport Land Use Commission has identified this condition as a safety concern relative to
obstructions and limited access in the event an aircraft were to make an emergency landing within
the RPZ.
In conjunction with the site-wide remedial activities, the wall will be demolished and the
containment berm will be graded to present a generally smoother topography. The conceptual
approach and anticipated impacts are presented in Appendix D.
As shown in Figure 14, this area also contains shallow surface soil impacted by arsenic. The
remedial action for this AOC will involve excavating the upper 1 to 3 feet of soil within the
delineated area and restoring the original grade with clean backfill material. The excavated
arsenic-impacted material will either be used as backfill material within the Northwest Operations
Area beneath the proposed cap or disposed of offsite.
6.8 LAND USE COVENANTS
Land use covenants will be provided as needed for the final parcels. This will include not only
potentially developable parcels, but also the open space areas. A land use covenant is a legal
document that will accompany a parcel’s deed. It will be signed by representatives of Chevron
and the lead agencies (e.g., RWQCB, County of San Luis Obispo, City of San Luis Obispo), and
will be notarized and recorded with the County Clerk/Recorder. It is intended to ensure that future
owners of the properties understand what mechanisms are in place at the site to protect human
health and the environment, and to identify for future property owners their responsibilities in
maintaining those protections.
The specifics of the land use covenants for the Tank Farm will vary depending on which parcel is
under consideration. It will, however, identify the allowed land uses and will exclude uses that
might be allowed under current or future land use planning but are inappropriate for the site. The
land use covenants will list the various caps and other containment features that must be
maintained. It will be accompanied by various documents, such as the guidelines for vapor barriers
(Appendix M) and the final Restoration Plan. The land use covenant will also restrict the use of
groundwater in areas of impacted soil on the Tank Farm property. Chevron will work with
adjacent land owners to establish covenants regarding soil and groundwater on adjacent properties
affected by historical site activities.
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Draft land use covenants (as required) will be prepared by Chevron for review by the RWQCB
and the lead municipality after the RAP has been approved and final covenants will be recorded
prior to any land transfers.
6.9 VAPOR BARRIERS
The FS identified the need for vapor intrusion mitigation as an engineering control in habitable
structures built in some of the development areas. Decomposition of the underlying hydrocarbons
generates methane and possibly hydrogen sulfide. In addition, benzene in the southern portion of
the Northwest Operations Area currently (i.e., pre-remediation) poses a potential risk to human
health. The RAP specifies that development areas will be capped to provide separation between
the underlying constituents and potential receptors. It is possible that capping alone may mitigate
vapor intrusion by preventing vapors from reaching the surface and accumulating within future
inhabited buildings. However, the conditions after capping or other remediation actions are
complete will be evaluated to determine if vapor intrusion has been mitigated or if additional
engineering controls need to be established.
As discussed in Section 1.4, upon completion of remedial actions, Chevron will prepare a
Certification Report documenting that the remedial action objectives of this plan were met and
submit it to the RWQCB for concurrence. At least one year prior to submittal of any Certification
Report(s) by Chevron, a vapor intrusion mitigation program will be developed and submitted to
the RWQCB and San Luis Obispo County Environmental Health Services for review and approval.
The program will include soil gas sampling protocols and a methodology for data evaluation to
determine if engineering controls (which may include further vapor intrusion mitigation) are or are
not needed. If feasible, the protocol will be applied to each individual parcel. For any parcels
where it is determined that engineering controls are needed, a land use covenant will be established
for the parcel(s) as part of the final Certification Report documents.
The examples provided in Appendix M are illustrations of typical, commonly used approaches for
construction of vapor intrusion mitigation systems. These approaches have been used on other
projects subject to methane and/or volatile organic compound intrusion, and have been approved
by numerous regulatory agencies and municipalities. All applicable land use covenants will refer
to the approaches included in Appendix M. In addition, these covenants will require that future
developers adhere to the most current vapor intrusion mitigation guidance that exists at the time
development occurs. Because such guidance is not a substitute for actual construction documents,
however, it is expected that future developers will use appropriate guidance in preparation of
development plans and specifications that will ultimately be subject to approval by permitting
agencies with appropriate jurisdiction.
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7.0 OPERABLE UNIT REMEDIAL ACTIONS
This section presents the remedial actions specific to each operable unit. It provides detailed
descriptions of how the remedial actions will be implemented, as well as the engineering and
regulatory bases behind their design. This section includes numerous figures meant to illustrate
the remedial actions, and while they are based on the engineering drawings found in Appendix C,
they should still be considered only diagrams.
7.1 OU #1 - NW OPERATIONS AREA
As described in Section 3.0, OU#1 (the Northwest Operations Area) consists of two media-based
areas of concern. The first, AOC #1, is groundwater, and the second, AOC #2, is soil. The
preferred remedy for AOC #1 is monitored natural attenuation with long-term monitoring and
institutional controls. The preferred remedy for AOC #2 is construction of a soil cap, with a
minimum thickness of 4 feet, long-term monitoring, and institutional controls to manage soil that
may be exposed during development or maintenance of the site.
7.1.1 AOC #1 - Groundwater
Monitored natural attenuation will be implemented using the same parameters and methods as
specified in Monitoring and Reporting Program 93-120 (Appendix B). However, remediation will
require abandonment of several monitoring wells (Table 2). Post-remediation monitoring wells
will be determined in consultation with the RWQCB, which will also approve future revisions to
the MRP. At a minimum, it is anticipated that initial post-remediation monitoring requirements
will include sampling and analyzing groundwater for TPH and BTEX (consistent with
MRP 93-120) at the remaining perimeter monitoring wells MW-49, MW-50, MW-56, and
SLOW-17, and the offsite production wells 11Ea and 11Eb. Currently, monitoring is performed
on a semiannual basis. After three years, the RWQCB will evaluate the semiannual groundwater
data to determine if a reduction in the monitoring frequency is warranted.
A land use covenant will be prepared for the operable unit that includes restrictions on the use of
groundwater. Those restrictions will prohibit installation of groundwater wells within or
immediately downgradient of petroleum-impacted soils.
7.1.2 AOC #2 - Soil-Development Scenario
It has been presumed in this plan that AOC #2 will be developed at some point in the future and
will not be considered suitable habitat for flora or fauna. As such, the remedial objectives are to
prevent human contact with the arsenic, TPH, and PAHs that are found in the shallow soil in this
area. Construction of a 4-foot-thick soil cap was selected as the preferred remedial alternative in
that it not only satisfied the remedial objective, but also made future development feasible by
raising the grade out of the 100-year flood plain. The 4-foot-thick soil cap will also be protective
of ecological resources until such time as development occurs. The remedial action for this AOC
also includes the removal of the upper 2 feet of soil (an estimated total of 675 cubic yards)
impacted by arsenic, which will be consolidated under the cap.
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Prior to building the cap, the site must be prepared for construction. Figure 21 illustrates the
demolition plan and subgrade preparation proposed for AOC #2. It is assumed that prior to
demolition, surveys of the currently occupied buildings have been completed for lead- and
asbestos-containing materials, the pipelines within AOC #2 have been either abandoned in place
or have been removed as described in Sections 6.2 and 6.4, respectively, and the monitoring wells
within the AOC will have been abandoned per Section 6.5.
After surveys and abatement have been completed, the
buildings will be demolished. Demolition will also
include removal of the existing fences and gates along
the south and west boundaries of AOC #2.
Future development of the region around the San Luis
Obispo Airport envisions widening Tank Farm Road to
a 100-foot-wide (or greater) right-of-way (City of San
Luis Obispo, 2005). This will necessitate moving the
southern boundary of the Northwest Operations Area
north approximately 30 feet or more (Figure 21). To
ensure that the historical infrastructure does not
interfere with future road widening, Chevron will
remove any existing features from this area, including pipelines and concrete foundations, within
the future right-of-way.
Prior to any significant demolition work, the site must be cleared and grubbed within the limits
shown in Figure 21 and more thoroughly defined on the construction drawings provided in
Appendix C. Clearing and grubbing will consist of removing all vegetation from the site. Brush
and small trees will be cleared by cutting them down and pulling up the roots. The site will be
grubbed to a depth of at least 3 inches using a tractor or small dozer to remove grasses and other
low-lying vegetation.
Northwest Operations Area along Tank Farm
Road - looking west
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There are two underground pipelines along the west
boundary of the Northwest Operations Area. One is a
2-inch-diameter natural gas line and the other is a
4-inch-diameter water supply line. The gas line is fed
by the 4-inch-diameter gas main located in Tank Farm
Road and owned by Southern California Gas Company.
The water line is fed by the existing water well located
adjacent to the southwest-most former tank ring, but is
also connected to other water lines across the property.
A series of timber poles support both electrical and
telecommunication lines. Along that western boundary
are drops to electrical panels that feed service to the
buildings. Chevron will remove the utilities along this
property line prior to constructing the cap. The gas line
will be cut and capped at the 4-inch main under Tank Farm Road. It will be necessary to coordinate
this work with The Gas Company. Similarly, the aerial utilities will be disconnected at Tank Farm
Road in coordination with AT&T and PG&E. Underground electrical and telecommunication
conduits supplying service to the demolished buildings will also be removed. Excavations to
remove buried conduits and pipelines will be backfilled with structural fill.
It is likely that Chevron will retain the existing water
well located adjacent to the southwest-most former tank
ring (Figure 21). The well is also shown in the digital
image below. Electrical service will be provided to the
well via an underground conduit after construction of
the cap. The location and specifications for the conduit
are provided in the design drawings found in Appendix
C. The conduit will be made of 4-inch-diameter
polyvinyl chloride (PVC) and will be buried at a depth
of 5 feet, in accordance with applicable local rules and
regulations for providing electrical service.
Northwest Operations Area along west
property boundary – looking north.
Northwest Operations Area - existing water
well
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Two septic tanks with leach fields manage wastewater at the Northwest Operations Area. One
tank serves the southern building and the other serves the northern building, as shown in Figure 21.
The tanks and leach lines will be abandoned in place in accordance with the standards of San Luis
Obispo County (2006). This will require emptying the tank contents with a vacuum truck,
supplying a receipt of the work to the County Inspector,
and then filling the tank with a cement slurry or
concrete.
There are six overhead light standards located around
the paved portion of AOC #2. These will be removed
and recycled or disposed of as appropriate. Concrete
foundations for the lights will be broken apart to a depth
of at least 2 feet bgs. The resulting hole will be
backfilled with structural fill. Conduits providing
electrical power to the lights will be cut at least 2 feet
below the existing grade and capped. Conductors will
be pulled and recycled.
A 10,000-gallon polyethylene water tank stores water
for firefighting at AOC #2. Once the buildings are
demolished, the tank will no longer be needed and will
be removed from the site. Water is supplied to the tank
by the 2-inch-diameter water line that enters near the
top of the tank. The larger 4-inch-diameter line
connects to a booster pump and then to the water
distribution system that feeds various hydrants
surrounding the site. Water level in the tank is
maintained by electronic sensors that ensure that a
minimum depth of water is present at all times. The
tank sits on a 4-inch-thick cast-in-place concrete slab
and is protected by four bollards. Once the tank has
been removed, the bollards will be pulled and the holes backfilled with a cement slurry or concrete.
The concrete slab will be broken apart and recycled onsite along with other concrete debris for use
as gravel. Water lines and conduits will be cut 2 feet below the existing grade, capped, and any
excavations backfilled with structural fill. Electrical conductors will be removed from the conduit
and recycled.
As can be seen from the above images and as indicated on Figure 21, AOC #2 is partially paved.
The pavement will be left in place. Any valve boxes or other similar types of subterranean vaults
not otherwise removed during demolition activities will be filled with cement slurry. Detachable
parking curbs will be removed for recycling, and asphalt edge curbs will removed.
Northwest Operations Area - fire water tank
Northwest Operations Area - typical light
standard
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The former fire school used a concrete-and-asphalt-
lined pit for teaching and training techniques for
extinguishing petroleum-fed fires (Figure 21). The
remains of the pit are shown in the adjacent image. It
may be difficult to place and compact structural fill
within the pit, which might result in unwanted
differential settlement. It is, therefore, proposed to
remove the loose debris in the bottom of the trench until
a firm surface has been exposed. The trench will then
be backfilled with cement slurry to the existing grade.
The loose material will be drummed, profiled, and
managed at an appropriately permitted facility.
Figure 21 shows that AOC #2 has concrete vestiges of the historical petroleum operations. Some
of these foundations are flush with the ground surface, or nearly so, and can be abandoned in place,
such as the one shown in the image below. Other concrete structures that project more than
6 inches above the ground surface will protrude above the subgrade preparation layer described
below and will interfere with construction of the cap. Consequently, the contractor may leave in
place any concrete structure that projects above the existing ground surface less than 6 inches.
Concrete structures that project more than that distance must be removed. The concrete may be
broken up and recycled onsite for use as gravel. The
contractor may elect to remove the low-lying concrete
structures, as well, if that proves more economic for
gravel production. Voids produced during removal of
the concrete structures will be replaced by structural
fill to the existing ground surface.
Once the work area has been cleared and grubbed and
the demolition and abandonment activities have been
completed, the subgrade will be prepared. This will
include compacting the existing ground surface to the
specifications of structural fill. In addition, a 6-inch-
thick layer of backfill will be placed over the entire
work area and compacted to the specifications of
structural fill. The intent of this effort is to provide a uniform surface over which to place the
geotextile fabric described later in this section.
A 12-ounce geotextile will be used to identify the contact between the cap and former ground
surface. It is intended to warn future construction workers that the underlying soil layers are
potentially contaminated. Specific warnings and instructions will be provided in the land use
covenants. Along the sloped soil boundaries, an anchor trench will be cut beneath the location of
the slope break, which is the point on the cap surface where the grade switches from a gentle slope
to a steeper slope that eventually meets the existing grade. The anchor trench will be at least 1 foot
Northwest Operations Area - burn trench
used by former fire school
Northwest Operations Area - typical concrete
slab requiring removal
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wide and 3 feet deep, and will be backfilled with structural fill. These end details are illustrated
in Figure 26.
The cap itself covers approximately 6.4 acres and will be constructed of structural fill. To promote
proper drainage across the site, the cap thickness varies from a minimum of 4 feet to a maximum
of approximately 7 feet towards the center. It is estimated that 53,400 cubic yards of structural fill
will be necessary to achieve the lines and grades depicted in Figure 22. It is anticipated that this
material will be obtained from the Flower Mound borrow source (Figure 16) by crushing run-of-
pit material to meet the specifications for common earth provided in Appendix E. The proposed
cap is thicker, on average, than the nominal thickness specified in the FS to provide adequate
flexibility for future development layouts. The proposed grading allows for surface runoff.
The Geotechnical Report identified potentially soft soils typically between 6 and 25 feet bgs,
although the depth varies, beneath the Northwest Operations Area. The settlement analysis
(Appendix H) estimates that settlement due to the load of the cap could be on the order of 4 to
6 inches. The Geotechnical Report estimated that additional settlement due to foundation loads
could be on the order of 1 to 2 inches.
In general, it is not considered practical to remove the soil for recompaction. Groundwater is
relatively shallow (on the order of 10 to 15 feet bgs ). As was discussed in Section 7.1.1,
groundwater in this area is affected by LNAPL, benzene, as well as TPH in the soil. The site
would require significant dewatering, with treatment of the resulting effluent, and disposal of
contaminated soils.
To address settlement concerns outlined in the Geotechnical Report, some recompaction of the
soils beneath the pipelines will occur as they are removed. To the degree possible during
remediation, soils will be stockpiled over the Northwest Operations Area to promote settlement.
This has the effect of surcharging the existing soils to provide for further compaction. During
construction of the cap, the Northwest Operations Area may also be used as a location for
temporary construction activities or stockpiling of material from the Flower Mound or other
borrow sites to further surcharge and provide compaction for the cap.
Construction of the cap will include installation of three survey monuments at the locations shown
in Figure 22 to facilitate settlement monitoring of the cap. An illustration of a typical survey
monument is shown in Figure 27. Should low spots develop following construction, they would
be repaired as part of the long-term maintenance program until the property is sold.
Future building foundations will require consideration of the soil conditions that will be included
in the covenants. Use restrictions will require that specific and detailed geotechnical studies be
prepared for any work subsequent to cap construction, that geogrid reinforcement or piles be
considered for foundation designs, and that any work below the bottom of the cap be in accordance
with an agency-approved plan to manage potentially impacted soil.
Storm water management features for this cap are designed to handle a 100-year recurrence storm.
Runoff is handled as sheet flow off the cap surface. It is directed from a high point near the mid-
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point of the site to ditches along the perimeter. It is carried in ditches to hardened drop points at
the locations shown in Figure 22. Drop structures have rip-rap reinforced energy dissipaters to
prevent erosion. The calculations used to size the storm water management features are found in
Appendix G.
Runon occurs at two locations and is diverted away from the cap at each. Currently, storm water
drains from the north toward where the cap will be constructed. Although the amount of flow is
relatively small, it is undesirable to allow this water to pond at the cap toe. Consequently, a flow
line will be established along the toe of slope that drains toward the existing ditches and wetlands
to the east. Ditches along the toe of slope are hardened with gravel and cobbles to minimize
erosion at the transition between the slope and the existing wetlands.
The other principal source of runon is from the west, along Tank Farm Road. A local high point
is located on Tank Farm Road approximately 1,000 feet west of the Tank Farm. Surface runoff
from the surrounding properties is directed toward the Tank Farm in the swale that runs on the
north side of the road. At present, the runoff drains onto the agricultural property adjacent to the
Tank Farm. During heavy precipitation, the attenuation capacity of that land is exhausted and
water drains onto the Northwest Operations Area as sheet-flow. Runon then flows across the
property, collecting in numerous local low points (including the southernmost building) until
reaching the wetland complex. The cap will cut off this route for storm water flow, and as such, a
new drainage ditch is proposed at the toe of the southern graded slope. The flow line of the new
ditch will start at the existing grade at the western edge of the property and drop to the floor of the
wetland complex to the east and will be sized to accommodate up to 17.2 cubic feet per second of
flow (Appendix G). Rip-rap will provide erosion protection at the entrance to the wetland
complex. The alignment and slope of the ditch are illustrated in Figure 22, and a typical cross
section is shown in Figure 23.
In addition to the erosion control measures previously described, additional BMPs will be provided
to minimize the potential for erosion from the cap to the wetland as detailed in a regulatory-
approved Stormwater Pollution Prevention Plan (SWPPP) for the project. Unmitigated, soil
erosion could be as much as 0.2 ton per year (Appendix J). It is anticipated that the recommended
BMPs outlined in the SWPPP will substantially lower this total. The ditches along the top of slope
of the cap will be provided with sandbag chevrons to slow water flow and allow sediment to drop
out of suspension. During construction, soil cement may be used to help stabilize exposed slopes
from erosion. Further, the surface and slopes of the cap upon completion will be covered with a
spray-applied mulch/seed, which will be maintained until the property is developed.
As discussed in Section 2.2, this portion of the site is within the 100-year flood plain of Tank Farm
Creek. Construction of the pad will locally remove approximately 12.4 acre-feet of flood storage
capacity. It is estimated, however, that further downstream (south of Tank Farm Road) there is an
additional 27.9 acre-feet of available storage capacity. Further, restoration of the North Marsh will
include expanding the existing wetland complex to provide addition flood storage capacity. This
is further discussed in the Hydrology Study (Avocet, January 26, 2009).
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As described in Sections 6.8 and 6.9, institutional controls will be adopted to protect the integrity
of the cap. The land use covenant will strictly define appropriate uses for the property. Excavation
depths will be controlled, and excavations deeper than the bottom of the cap will be conducted
under the requirements of the Soil Mitigation Plan. Prior to development of the site, access will
be controlled through fences and gates. Additional fences will be installed around the interior
boundary of the operable unit with a locking gate, as shown in Figure 22, to control access between
the development area and the adjacent open space. Prior to development, the cap will be
periodically inspected and maintained, as necessary. Proposed ICs and ECs are summarized in
Table 1.
7.2 OU #2 - RESERVOIRS 5 AND 7
The primary remedial action objective for Reservoirs 5 and 7 (i.e., OU #2) is to prevent the
emergence of liquid hydrocarbon on the open water that accumulates at these locations. The sheen
produced by the liquid hydrocarbon may adversely affect ecological receptors such as water fowl.
The FS determined that the most feasible way to prevent contact is to cap the reservoirs in a manner
that allows groundwater (and the overlying hydrocarbon) to fluctuate naturally and not try to find
alternative (i.e., lower resistance) flow paths.
Prior to constructing the cap, it will be necessary to clear the work area. The demolition plans for
Reservoirs 5 and 7 are illustrated in Figure 28 and Figure 29, respectively. The detailed
engineering drawings for demolition are included in Appendix C. A proposed work area boundary
has been established for each reservoir. This boundary establishes where the contractor may
operate his equipment, disturb habitat, and where cleanup and construction will take place. The
contractor will identify the work boundary in the field and provide protective measures to prevent
impacts outside of the boundary. These will include cones, caution tape, temporary fencing (if
appropriate), silt fences, and other dust and erosion
control BMPs.
One of the first demolition tasks will be the removal of
the protective enclosures, an example of which is shown
in the adjacent image. These enclosures were installed
to ensure that small animals, such as birds, are not
entrapped in sticky plastic hydrocarbon surface
expressions. They occur both inside and outside of the
reservoir berms. Every location with a protective
enclosure is presumed to overlie a surface expression of
plastic hydrocarbon that requires removal. Those within
the limits of the former reservoir berm are addressed as
part of the cap construction. Outside of the berm limits soil beneath the protective enclosures will
be removed as described in Section 4.2. Note that there are some plastic hydrocarbon surface
expressions outside of the Reservoir 5 work area (Figure 28). Excavation and impacted soil
removal at this location is addressed in Section 7.4.3. The enclosure materials will be removed
from the site by the contractor and recycled (if feasible) or disposed of in a solid waste landfill.
Reservoir 5 - typical protective enclosures
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The protective enclosures will be removed immediately prior to construction activities within each
respective area so as to minimize exposure of surface expressions to wildlife to the extent practical.
Other site preparation activities will include the removal
of any pipeline remnants in the work area. The old 8-
inch-diameter crude oil distribution line is nearly tangent
to the southwest edge of the Reservoir 5 berm. A lateral
from this line appears to branch into Reservoir 5. The
remains of the lateral can be seen ending within the
reservoir in the above image. The remains of the 12-inch
and 8-inch lines that served Reservoir 7 may also still be
present underground. The concrete superstructure that
supported those lines is still visible in the reservoir (see
adjacent image). It is expected that the 4-inch-diameter
fire water line shown surrounding Reservoir 5 (Figure 5)
is still present. Since Reservoir 7 was abandoned after
the 1926 fire, an upgraded fire water line was never installed at that location.
If a pipeline is exposed or is encountered in grubbing, scarifying, or obtaining borrow soil, it will
be removed and disposed of as described in Section 6.4.4. Those portions of existing lines that lie
outside of the work area will be cut, flushed, pigged (if possible), and capped as described in
Section 6.4.2.
There is a lot of concrete and concrete debris within the
work boundary of each reservoir. This includes old
pump and lightning tower foundations, valve boxes,
vaults, and other supports that were used during
historical operations. There are also several small piles
of broken concrete on the floor of Reservoir 5 (Figure
28). It also includes the concrete walls of the reservoirs
that were cast on the berm slopes. The approximate
extent of the walls for Reservoirs 5 and 7 is illustrated
in Figure 28 and Figure 29, respectively. Although
there appears to be little of the original walls left in
Reservoir 5, much of the original walls remain in
Reservoir 7 (see adjacent photograph). Concrete debris will be removed from the work area. If
practical, it will be recycled to create crushed gravel for use on this project. Otherwise, it will be
hauled offsite for recycling. Concrete that is too impacted by petroleum for reuse will be hauled
away for disposal at an appropriate facility.
Two monitoring wells in OU #2, both located within Reservoir 5 (see Figure 28), will be destroyed.
The monitoring wells are within the proposed cap boundaries. The procedures described in
Section 6.5 will be used to abandon the monitoring wells.
Reservoir 5 – former oil pipeline
Reservoir 7 – overview of existing bottom and
concrete-lined slopes
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It will also be necessary to remove the seepage study equipment that was installed to determine
the process by which sheen formed on the open water of the reservoirs and which contributed to
the design of the caps proposed in this RAP. The structures were constructed by excavating holes
into the reservoir bottoms and installing large-diameter corrugated metal pipes on end. The
annular space between the corrugated metal pipes and the soil was sealed with grout. The interiors
were partially filled with clean sand and were instrumented to monitor water levels. Observations
of water and LNAPL levels within the structures and the surrounding monitoring wells provided
our current understanding on sheen formation.
Any remaining instrumentation will be removed from the structures and returned to Chevron for
final disposition. Any remaining PVC sounding tubes will be pulled from the ground and disposed.
The corrugated metal pipes will then be pulled from the ground using a backhoe or similar large
piece of equipment. Any resulting void space will be filled during placement of the gravel layer,
as described below.
Other debris, concrete, or metal that is discovered within the work area will also be removed. This
will include the metal posts that are encountered at various locations, wire, fire hydrants, and other
debris. Metal and concrete will be recycled where practical. Other materials will be disposed of
as appropriate to their characteristics.
The last step prior to constructing the cap will be to
expose the original concrete floor of the reservoirs. As
can be seen in the adjacent image, there is a variable
thickness of accumulated soil and organic matter. It is
estimated that Reservoir 5 will generate 15,300 cubic
yards and Reservoir 7 a further 11,000 cubic yards, for
a total of 26,300 cubic yards. This will be stripped and
disposed of at an appropriately permitted facility.
Equipment used to strip this material will be properly
decontaminated to remove any accumulated oily soil
before being used to move clean soil elsewhere onsite.
Material removed as part of the decontamination
process will be disposed of along with the stripped
reservoir material. Implementation of this part of the remediation will be most successful if
accomplished in the summer, fall, and possibly early winter if there is little precipitation that year.
Remediation may be postponed during periods of high groundwater levels and water in storage in
the reservoirs. Once construction has begun, it should be finished as quickly as possible to prevent
having to manage petroleum-impacted water.
The proposed grading plans for Reservoirs 5 and 7 are illustrated in Figure 30 and Figure 31,
respectively. A diagram of the cap profile is shown in Figure 32. The engineering drawings
(Appendix C) include the detailed designs for the caps.
Reservoir 7 – accumulated debris in reservoir
bottom
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Once the floor has been exposed, the reservoir bottom can be backfilled with gravel. As described
in Section 5.3, this material will be selected and placed so that it provides a low-resistance pathway
for groundwater and LNAPL to move into during their seasonal fluctuations. Consequently, it is
desirable to have a relatively uniform material with little to no fine material (i.e., particle size less
than No. 200 sieve). This will create large void spaces with little resistance to flow and a low
likelihood of future clogging. The gravel will be placed in lifts no greater than 12 inches thick and
will be nominally compacted by one pass of a steel drum roller.
Placement of the gravel will be controlled by the nominal top-of-layer elevation. These elevations,
119.20 feet above mean sea level (amsl) for Reservoir 5 and 123.50 feet amsl for Reservoir 7, are
based on the relative differences between the known concrete floor elevations and the highest
observed local groundwater elevation plus a 1.5-foot factor-of-safety. The top of the gravel is
above the downgradient ground surface of the reservoirs. Water cannot rise above this elevation
within the reservoir without daylighting outside the reservoir, thereby controlling water levels
within the reservoirs. The floor elevation of Reservoir 5 is 115.50 feet amsl, and the highest
measured groundwater elevation between 1999 and 2002 was 117.70 feet amsl. Similarly, the
floor elevation of Reservoir 7 is known to be 116.50 feet amsl, and the highest recorded
groundwater elevation was 122.00 feet amsl.
The top of the gravel layer can be no less than the specified design elevations, and results in a
minimum thickness of 3.7 and 7 feet for Reservoirs 5 and 7, respectively. It will be acceptable for
the contractor to allow the gravel layer to be thicker, but the final surface cannot have depressions
or low spots that dip below the nominal top-of-layer elevations. As shown in Table 4, it is
estimated that 20,100 cubic yards of gravel will be needed to fill Reservoir 5, and another 39,000
cubic yards will be needed for Reservoir 7.
A 12-ounce 4 geotextile will be placed over the gravel to prevent migration of fine soil particles
into the void spaces from the overlying soil layers. The geotextile will be anchored in a trench
dug around the original concrete floor. The trench will be dug into a shelf cut into the existing
berm. The shelf will be approximately 3 feet wide. It is anticipated that the trench will be dug by
a small pocket-size excavator with an arm that can be offset from the machine’s centerline. The
trench will be centered in the shelf and will be approximately 1 foot wide and 3 feet deep. The
configuration of the shelf and anchor trench is illustrated in Figure 33. The trench locations for
Reservoirs 5 and 7 are shown in Figure 30 and Figure 31, respectively. The geotextile will be
placed as required by the manufacturer. This will include trimming the edges that go into the
anchor trench and sewing adjacent rolls together at their overlapped edges. Pro-forma calculations
have been included in Appendix I that demonstrate the selected geotextile will prevent soil
migration, has adequate tensile strength, and that the anchor trench is sized appropriately to prevent
pull-out.
4 Geotextile is typically identified by its weight per square yard. Therefore, an 8-ounce fabric weighs 8 ounces per
square yard.
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The final grades shown in Figure 30 and Figure 31 will be achieved by placing common fill with
a 1-foot surface veneer of topsoil over the geotextile. The objective with these grading plans is to
produce as natural-looking of a landform as possible. The final grade will be nominally controlled
by grading from a control contour established near the top of the cap. The surface will slope at no
more than 4:1 (horizontal:vertical). Ditches will be established around the perimeter of the cap to
ensure proper runoff of storm water. The final configuration of the slopes and ditches will be
developed in the field to best integrate with the surrounding topography within the other
parameters of the design. It is estimated that Reservoir 5 will require 12,500 cubic yards of
common fill and 12,600 cubic yards of topsoil. As shown in Figure 30, the berm borrow around
Reservoir 5 could generate another 26,300 cubic yards of common earth that could be used for fill
around the site. This material will only be removed if needed elsewhere onsite. Reservoir 7 is
expected to require 24,500 cubic yards of common earth and 11,000 cubic yards of topsoil for cap
construction. An additional 8,300 cubic yards of soil are potentially available from the local berm
borrow if needed elsewhere onsite.
The slopes and ditches are designed to minimize potential erosion. The ditch slopes will vary
between 0.5 and 2 percent and are designed to accommodate the 100-year return period storm.
The discharge points of each ditch are provided with some type of energy dissipation. Where
velocities are less than 2 feet per second, a simple gravel mat is supplied. If the exit velocities are
greater than 2 feet per second, a reinforced rip-rap energy dissipater will be installed. The
hydrology and hydraulic calculations supporting the ditch dimensions and energy dissipaters are
found in Appendix G.
The U.S. Soil Conservation Service recommends limiting soil erosion to less than 2 tons per acre
per year. The calculations in Appendix J show that the estimated annual soil loss from the caps is
0.53 ton per acre and 0.77 ton per acre for Reservoirs 5 and 7, respectively.
The surfaces of the Reservoir 5 and 7 caps will be revegetated with an approved native plant seed
mix as determined in the Restoration Plan. The surface of the cap will be scarified to a depth of
at least 3 inches. Prior to the onset of the rainy season, and preferably as close as possible to the
season’s first rain, the seed mix will be applied. The caps will be protected after application of the
seed with jute net or spray-applied mulch that will minimize erosion until the vegetation can take
root.
As noted previously, remediation of the Tank Farm results in unavoidable impacts to existing
wetlands, some of which include desirable VPFS habitat. The demolition plans depict the wetlands
on and around Reservoirs 5 and 7. Impacted wetlands are shown in blue, while wetlands not
affected by construction are shown in green. Some of the wetland impacts will be temporary and
the existing wetlands will be reestablished after remediation is complete. Those impacts that are
permanent will be mitigated onsite. A summary of estimated habitat impacts will be provided in
the Restoration Plan.
Settlement is not anticipated to be a significant issue for the Reservoirs 5 and 7 caps. The caps
will be constructed over the original concrete floors, which will tend to evenly distribute the
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overlying soil loads. The cap is further reinforced by the geotextile, which, within limits, will also
distribute loads and provide a bridging support over localized weak spots. In addition, it is likely
that the soils directly beneath the reservoir are overconsolidated; that is, they have experienced
greater bearing stress than they currently experience. The reservoirs were loaded with a 20-foot
or more thickness of oil for many decades. That historical load will have worked to compress the
soils, and it is expected that additional settlement should be minimal.
To ensure proper performance of the caps, future settlement will be monitored in conjunction with
the MRP. Three monuments will be placed on and around the cap, as shown on the grading plans
for each of the caps. The monuments will be of a standard design acceptable to the City or County.
Typically, a survey monument will consist of a 5/8-inch-diameter steel or aluminum rod between
3 and 5 feet in length. The rod is driven into the ground and then topped with a domed cap that
threads onto the rod. One monument will be located on the top of the cap, another near the edge,
and a third at a location adjacent to the cap on native ground. Monitoring of the cap will be as
described in Section 9.0
7.3 OU #3 - RESERVOIR 4
OU #3 is located on the eastern side of the Tank Farm north of Tank Farm Road (Figure 14). As
noted in the FS, this area includes the remains of Reservoir 4, and has several plastic hydrocarbon
surface expressions that pose potential entrapment hazards. Chevron has elected to implement a
closure approach for this OU that supports future development in accordance with the proposed
land use plan (Figure 10). This entails excavation of the surface expressions and construction of
a cap over the former reservoir.
The work area boundaries for OU #3 are shown in Figure 34. Site disturbance associated with
remediation of OU #3 will be confined to this area. Preparation of the site for remediation will
include clearing, grubbing, removal of the protective enclosures and monitoring wells, and
demolition and removal of concrete debris and pipeline remnants. Protective enclosures will
remain in place for as long as practical to minimize exposure of wildlife to the existing surface
expressions. A demolition plan for the Reservoir 4 area is shown in Figure 35. Clearing and
grubbing will remove vegetation from the work area. Grubbed vegetation will be managed as
allowed by San Luis Obispo County, the RWQCB, and the SLOAPCD.
A chain link fence secures the property along Tank Farm Road and along the eastern property line.
A barbed-wire fence separates the Reservoir 4 area from other portions of the site. The barbed-
wire fences are used by ranchers to create paddocks suitable for cattle grazing. The chain link
fence will be maintained, except that minor modifications will be made in its alignment to
maximize the working area. The barbed-wire fence will be removed.
One monitoring well (TMW-9) will be abandoned within OU #3. This well is included on the list
in Table 2. The wells will be abandoned as described in Section 6.5. Two monitoring wells along
the southern boundary of OU #3, MW-17 and MW-18, may need to be either modified or removed
and replaced following completion of grading activities. Replacement of wells needed for post-
remediation monitoring will be determined in consultation with the RWQCB.
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There are four protective enclosures clustered adjacent to the northwest boundary of Reservoir 4.
These will be removed and recycled or disposed of as appropriate. It is presumed that plastic
surface expressions are beneath each of these enclosures.
The underlying soil will be excavated in accordance with
Section 4.2 and the more specific descriptions found later
in this section. Protective enclosures will remain in place
for as long as practical to minimize exposure of wildlife to
the existing surface expressions.
Concrete foundations for the lightning towers and pumps
are still found surrounding the reservoir (Figure 35). These
will be removed from the work area and crushed for use as
gravel elsewhere on the site, or will be sent offsite for
recycling. In addition, frames constructed of wood and
concrete (believed to be test plots from a previous study) are found on the west side of the reservoir.
These will be removed for disposal at a permitted facility.
The remains of the foundations for the reservoir roof and interior wall can be seen in the field and
are shown in Figure 35. The contractor can abandon these foundations in place if approved by the
Geotechnical Engineer and they do not interfere with achieving the lines and grades shown in
Figure 38. The contractor will also have the option of recovering the foundations to create gravel
for use elsewhere onsite if feasible.
Crude oil and water lines historically served Reservoir 4
(Figure 5). It appears that most of the crude oil line has
been removed (see adjacent image), or is possibly buried
within the reservoir. There are exposed portions of the
water line, but it is believed to be substantially intact due to
the hydrants that still surround the reservoir (Figure 35).
The remains of the crude oil line will be exposed and
removed to a point outside of the work area. Some of the
water line is exposed at the surface; other portions are
within the area that will be used as common earth borrow
for the cap construction. As such, the water line will be cut
at the three locations where it appears to enter the work
area. Those portions within the work area will be removed, while those sections outside of the
work area will be capped and managed as described in Section 6.4.
Figure 37 shows the areas where soil has been impacted by plastic hydrocarbon. This area is
approximately 8.35 acres and is estimated to contain as much as 40,400 cubic yards of impacted
soil. The contractor will segregate plastic-hydrocarbon-impacted soil from asphaltic material and
clean soil during the excavation. Those nonimpacted materials can be incorporated into the
structural fill for the cap. Excavation will be performed as described in Section 4.2. The remaining
Reservoir 4 – abandoned oil pipeline
Abandoned concrete lightening stand
foundation
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subgrade will be compacted to at least 95 percent of its relative maximum density per ASTM
D1557.
Geotextile will be used to identify the cap bottom and to provide some structural support in the
event of differential settlement. The potential for settlement is discussed later in this section.
Approximately 342,900 square feet of geotextile will be anchored in a trench positioned around
the former reservoir as shown in Figure 37. The trench will be 1 foot wide and 3 feet deep.
Calculations estimating the resistance to pull-out for this trench (including potential strain induced
by differential settlement) are provided in Appendix I.
The proposed grading plan for the Reservoir 4 cap and the Flower Mound is shown in Figure 38.
The grading plan ensures a minimum of 4 feet of cover over the former reservoir bottom. The
maximum thickness is approximately 11 feet, and the average thickness is just over 6 feet. On the
east side of the grading area, approximately 900 feet north of Tank Farm Road, is a small drainage
basin that collects runoff from the entire grading area.
It is estimated that this grading plan will require approximately 262,800 cubic yards of structural
fill. The Flower Mound borrow area is expected to generate at least 328,200 cubic yards, and up
to 402,000 cubic yards if Chevron has access to the offsite material, so there is adequate fill
material in the vicinity. Some of the excess may be used to regrade Borrow Area No. 2. After
topsoil removal, structural fill will be placed as shown in Figure 39.
Enhancement of existing drainages and the construction of new channels and detention features
are required to adequately manage storm water. The features shown in this RAP are conceptual
and intended to be temporary, although they may be used for several years. Final BMPs will be
coordinated with the restoration efforts and shown in the construction plans and SWPPP, which
will be submitted to the RWQCB for review in conjunction with permit processing.
Supporting hydrology and hydraulics calculations for the overland system are provided in
Appendix G. The hydrologic design point for the area north of Tank Farm Road is identified on
Figure 38. Overall, the peak flow to this point has been reduced, mostly due to the longer travel
path that water must flow over, which results in a longer time of concentration. The existing peak
flow at this point during the 100-year storm is estimated to be 67 cubic feet per second. The peak
flow for the same storm after grading is estimated to be approximately 51 cubic feet per second.
Most of the graded areas will drain by sheet flow to the rough graded interior roads. These roads
collect storm water and direct it to large, oversized, constructed swales along Tank Farm Road and
the north property boundary. The larger swale along Tank Farm Road discharges to an even larger
swale along the toe of the collector road slope. That swale and the swale along the northern
property line discharge to a small sediment removal basin just before the design point (Figure 38).
The swales are broad and will be roughened and vegetated to reduce flow velocities, minimize
erosion, and limit sediment transport.
Regrading of Borrow Area No. 2 will alter the hydrology. At present, precipitation is trapped in a
closed catchment. Rough grading of the City of San Luis Obispo’s proposed Santa Fe Road
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extension will permit 2.9 acres to discharge directly to the East Fork of San Luis Obispo Creek.
The peak flow of this discharge during the 100-year storm is estimated to be 5.1 cubic feet per
second. This is a relatively minor contribution to the overall flow of the creek, and is unavoidable
if Santa Fe Road is to be extended as described in the AASP (City of San Luis Obispo, 2005).
In addition to the erosion control measures previously described, additional BMPs will be provided
to minimize the potential for erosion from the cap to the wetlands. Unmitigated, soil erosion could
be as much as 1.38 tons per acre per year (Appendix J). It is anticipated that the BMP regime will
substantially lower this total. Possible BMPs include, but are not limited to, silt fences, sand bags,
and fiber rolls. Final BMPs will be coordinated with the restoration efforts and shown in the
construction plans and SWPPP, which will be submitted to the RWQCB for review in conjunction
with permit processing.
Remediation activities in OU #3 and the Flower Mound will affect wetlands, VPFS habitat, and
rare plant communities. A summary of impacts to wetlands, VPFS habitat, and rare plant
communities and corresponding mitigation will be provided in the Restoration Plan.
It was noted previously in this section that there is a potential for settlement to occur. It is believed
that decommissioning of Reservoir 4 included pushing berm material over the concrete floor. Field
inspections of this material indicate that it has not been compacted. The Geotechnical Report
(Padre, 2007a) estimated that settlement may be on the order of 3 to 4 inches. During construction,
the upper few feet of existing material will be compacted. It is not intended, however, to expose
and recompact petroleum impacted soils. The cap thickness of 11 feet is expected to address
settlement and support issues. In addition, a 12-ounce geotextile will be used to provide additional
tensile strength and load distribution capacity.
With respect to future building foundations, developers will be required to comply with land use
restrictions contained within the land use covenants. Covenants will require that specific and
detailed geotechnical studies be prepared for any work subsequent to cap construction, that geogrid
reinforcement or piles be considered for foundation designs, and that any work below the bottom
of the cap be in accordance with an approved plan to manage potentially impacted soil.
Potential settlement of the cap will be monitored through the use of survey monuments. It is
proposed that five monuments be installed in and around this operable unit. Their locations are
shown in Figure 38. A typical survey monument detail is shown in Figure 27. The survey
monument consists of a 5/8-inch-diameter steel or aluminum rod driven to a depth of between 4 to
6 feet bgs. The rod is topped with a threaded cap mounted flush with the ground that identifies the
monument. The monuments will be periodically surveyed as part of the long-term maintenance
requirements for the site.
In addition to possible high-load foundation requirements, the land use covenant will specify the
various ICs and ECs that will accompany title to the property. Proposed ICs and ECs are
summarized in Table 1. These will include limitations on excavation, impacted soil management
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requirements, and general guidelines on the use of vapor barriers for habitable structures. An
example of these guidelines is provided in Appendix M.
7.4 OU #4 - REMAINING SITE-WIDE TERRESTRIAL AND WETLAND AREAS
The remaining site-wide impacted terrestrial and wetland areas are addressed as OU #4. It includes
three areas of concern. The first, AOC #1, is the North Marsh adjacent to the Northwest Operations
Area. The second, AOC #2, is Reservoir 3, and AOC #3 is the remaining plastic (“sticky”)
hydrocarbon surface expressions.
7.4.1 AOC #1 - North Marsh
The North Marsh is a large (approximately 11.9-acre) wetland complex adjacent to the Northwest
Operations Area. The SERRT identified this area as requiring remediation as a result of the
numerous surface expressions that posed potential entrapment hazards to small animals. After
careful consideration, Chevron determined, and documented in the FS, that the preferred approach
to remediation would be to excavate the hydrocarbon material and restore the wetland in place
with improved function and environmental utility.
The anticipated work area for OU #4/AOC #1 is defined by the clear and grub line shown in Figure
41. Every attempt will be made to minimize working outside of the excavation limits. However,
it is also recognized that the excavation areas may expand in order to fully capture the hydrocarbon
materials within the wetland.
The contractor will, to the extent possible, stockpile and protect cleared wetland vegetation.
Greater detail regarding selecting, segregating, stockpiling, and maintaining vegetation will be
provided in the final Restoration Plan. One possible stockpile location is shown adjacent to the
North Marsh in Figure 41. Other locations can be used, as necessary, as long as they minimize
impacts to existing and otherwise unaffected habitat.
There are three protective enclosures within the work area. These will be dismantled and removed
for disposal or recycling, as appropriate. Since they are each within the wetland, the presumption
that they enclose plastic hydrocarbons is addressed by the excavation described later in this section.
Protective enclosures will remain in place for as long as practical to minimize exposure of wildlife
to the existing surface expressions.
As discussed in Section 5.5.4, the facility used a location adjacent to the wetland for debris disposal
following the 1926 fire (Figure 41). This material will be removed. It may be recycled into gravel
for use elsewhere on the site (if feasible), or it may be removed from the site for recycling.
There are two monitoring wells in the work area that will be abandoned, B-36 and SP-4. They are
more fully described in Table 2 and their locations are shown in Figure 41. The wells will be
abandoned as described in Section 6.5. There are three other monitoring wells (B-33, B-35, and
MW-16) that are immediately adjacent to the work area. These will be protected in place if
possible.
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PG&E and AT&T have utilities (power and telecommunications, respectively) that cross the work
area adjacent to Tank Farm Road (Figure 41). The contractor will be responsible for protecting
those utilities in place or relocating as needed.
Several of the old facility pipelines intrude into the excavation area, as shown in Figure 41. The
historical records indicate that there are a water line and two Foamite lines in the north part of the
excavation limits crossing in an east-west direction (approximately 400 lineal feet each in the work
area, approximately 1,200 lineal feet total). These lines appear to have been used for fire
suppression purposes at the 55,000-barrel ASTs. There are two former crude oil lines that cross
the excavation area in an east-west direction almost at the midpoint (approximately 860 lineal feet
each in the work area, 1,720 feet total). A water line and natural gas line (the latter is reported to
have been abandoned) run parallel to Tank Farm Road in the unpaved shoulder area
(approximately 270 lineal feet each in the work area). Another water line is found at the southwest
end of the excavation area crossing in a north-south direction. A stub off that line protrudes into
the excavation area approximately 60 feet in an easterly direction.
It is likely that pipeline abandonment will occur prior to remediation in the North Marsh. As such,
the lines will have been cleaned, as needed. If the lines are not exposed during excavation, they
will be abandoned in place as described in Section 6.4. If the lines are exposed during excavation
of the North Marsh, they will be removed for disposal. The lines will be cut approximately 10 feet
outside the work area. The exposed pipeline end will be capped and the local excavation will be
backfilled with common fill.
A preliminary excavation boundary is shown in Figure 41. It is believed that this boundary
includes all of the hydrocarbon expressions that affect the North Marsh. The boundary is
delineated in this way mostly for permitting purposes so that the potential maximum impact is
quantified in the environmental analysis. The entire excavation boundary, as shown in Figure 41,
covers over 13 acres. The FS estimated the average thickness of impacted soil to be 3.5 feet.
Excavating to this depth within the boundary would generate 75,300 cubic yards of soil, most of
which will require offsite management. The mapped hydrocarbon surface expressions, in contrast,
are only 7 acres (including the protective enclosures). Excavation limited to this area would result
in a correspondingly lower volume (approximately 40,000 cubic yards). The actual volume is
anticipated to be somewhere between these extremes, but the larger quantity will be used for
planning purposes.
Excavation is expected to proceed from the north to the south. This allows haul trucks to most
readily access either Tank Farm Road for offsite disposal or the temporary impacted soil stockpile
in the Northwest Operations Area. The potential haul routes are shown in Figure 17. The access
point from Tank Farm Road shown on the figure is preferred since the RAP envisions some form
of active traffic control at this location while work is in progress.
Although remediation of the North Marsh will create the single largest waters/wetlands impact for
the entire Tank Farm project, it does not affect any VPFS habitat, and the impacts are only
temporary. In fact, remediation is expected to increase the size of the habitat when the historical
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debris disposal area is cleaned up. Impacts to waters/wetlands and rare plant communities and
specifics for restoration of the North Marsh will be discussed in the Restoration Plan.
7.4.2 AOC #2 - Reservoir 3
Reservoir 3 was one of the largest reservoirs and one of the last to be decommissioned. Although
it contains a large wetland complex, it is unlike Reservoirs 5 and 7 in that the wetland is not of the
open water type. Rather, it is generally a wet-marsh-type, with areas of plastic hydrocarbon
exposed at the surface where it poses a physical, and possibly chemical, hazard to ecological
receptors. Further, the wetland does not appear to be fed by groundwater, again distinctly different
from the wetlands in Reservoirs 5 and 7. The preferred remedial alternative for this area of concern
is to remove a limited amount of impacted material and replace it with the cap components, which
will include geosynthetics that will create an impermeable barrier and help to support the overlying
cap materials. This is anticipated to allow replacement, and possibly expansion, of the existing
wetlands.
The work area for Reservoir 3 is shown in Figure 42. This work boundary includes the adjacent
wetland complex to the northwest that is impacted by plastic hydrocarbon surface expressions.
Preparation of this work area will include clearing, grubbing, removal of concrete debris for
recycling or disposal, dismantling and removal of the protective enclosures, and removal of
exposed pipelines. Protective enclosures will remain in place for as long as practical to minimize
exposure of wildlife to the existing surface expressions.
There appears to be less concrete debris surrounding this
reservoir than the others across the Tank Farm. There are
a couple of lightning tower stands and some other loose
concrete debris that will be removed for recycling. The
remains of the original concrete that lined the reservoir
berm slopes can also be observed at the ground surface
(see adjacent image). Those portions that are within the
excavation limits (Figure 42) will be removed for
recycling as well, assuming that they are not heavily
stained with hydrocarbon. Heavily stained concrete will
be removed for disposal at an appropriately permitted
facility.
Reservoir 3 – former concrete wall
foundation
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Reservoir 3 also contains the single largest protective
enclosure on the Tank Farm. This enclosure and the one
just outside the berm to the north of the reservoir will be
dismantled and removed from the work area. If practical,
the materials will be salvaged or recycled. If this proves
impractical, the contractor will dispose of the materials at
an appropriately permitted facility.
A single abandoned pipeline approaches the reservoir
from the north (Figure 42). It is uncertain if the line even
continues into the reservoir. The line will be flushed,
pigged (if practical), and abandoned in place (as described
in Section 6.4), assuming that it does not interfere with excavation or construction of the cap. If
this assumption proves incorrect, the pipeline will be cut outside the work area, capped, and the
portion inside the work area will be removed for disposal.
The water supply line that served Reservoir 3 appears to be well out of the proposed work area
and is not expected to affect the work in this area of concern. It does appear, however, that the
water line crosses several of the other plastic hydrocarbon surface expressions adjacent to the
reservoir. Managing the water line at these locations is described in Section 7.4.3, below.
The preferred remedy developed in the FS recommended removing approximately 2 feet of
existing material and replacing it with the components of the cap. Nominally, this would be
effective in that the work area is essentially flat, though slightly higher in the center and the east.
The resulting depression supports the wetland habitat in this area. The refined approach in this
RAP is to remove the minimum 2 feet of material at the outer edge of the excavation, but to deepen
the excavation in the center of the reservoir so that the excavated bottom has a 0.5 percent slope
toward the interior. It is anticipated that this excavation will generate approximately 26,700 cubic
yards of hydrocarbon-impacted soil that will require removal and disposal. The excavation will
start at elevation 134, which is also the elevation that the top of the cap ties into the existing ground
along the outer edge of the reservoir. The entire surface of the cap will then be approximately the
same elevation as the existing wetland complex, which should allow restoration and expansion of
the existing habitat.
The subgrade surface will be compacted to a depth of 6 inches to 90 percent of its relative
maximum density per ASTM D1557. Construction equipment may require decontamination after
compaction of the subgrade. Depressions in the subgrade resulting from compaction will be
restored to the lines and grades of the design with common fill. A liner system will be installed
over the subgrade to prevent the remaining hydrocarbon materials from migrating to the surface.
The liner system will consist of (from bottom to top): 12-ounce geotextile; a 12-inch layer of
gravel with a triaxial geogrid installed mid-thickness; 12-ounce geotextile; 40-mil high density
polyethylene (HDPE) liner; 12-ounce geotextile; variable thickness (0-18 inch) common fill; and
1-foot thickness of topsoil. An illustration of the liner section and the anchor trench detail is shown
in Figure 44.
Reservoir 3 – protective enclosure
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The lower portion of the liner system is intended to bridge potentially soft portions of the remaining
soils in the reservoir. A 12-ounce non-woven geotextile will be installed to ensure that fine soil
particles do not migrate into the gravel layer. A 6-inch thickness of gravel will be placed over the
geotextile. The initial 6-inch layer will be nominally compacted by at least one pass of a steel
drum roller. A triaxial geogrid (Tensar TX-160, or equivalent) will be installed per manufacturer’s
specifications and secured in an anchor trench around the perimeter of the original reservoir bottom
(Figure 43). The geogrid will be covered with an additional 6-inch layer of gravel.
As noted above, the purpose of this component of the liner system is support. For design purposes,
it has been assumed that the center of the cap tries to settle by approximately 2 feet, equivalent to
a 50 percent consolidation of the original impacted soil remaining between the excavation bottom
and the original reservoir bottom. While each of the geosynthetic materials can readily accept the
resulting strain, it is expected that the strain will be taken up first by the geogrid, which is designed
for this type of application. Further, the geogrid will better distribute loads across the foundation,
lessening the potential for differential settlement. This type of geogrid better at locking aggregate
materials and provides superior load distribution than bi-axial geogrids. Supporting calculations
for the geosynthetics are provided in Appendix I.
Three additional geosynthetic components will be placed on the compacted gravel. These will
consist of a 40-mil HDPE flexible membrane liner (FML) over a 12-ounce non-woven geotextile
and beneath a 12-ounce non-woven geotextile. The FML creates an impermeable barrier to future
migration of hydrocarbon-impacted soils. It also will minimize infiltration losses from the
overlying wetland. The primary purpose for the geotextiles is to protect the FML from punctures
and abrasions due to angular particles in the common fill. A secondary purpose for the geotextiles
is to assist in distributing soil loads and bridging soft soils. Since the subgrade slope is so mild
(0.5 percent), the use of smooth rather than a textured FML will be acceptable.
A variable thickness of common fill will be used to create a nominally level surface across the
reservoir. It will be as much as 18 inches thick in the center of the reservoir and will taper out as
it reaches the anchor trench bench (Figure 44). The common fill will be pushed onto the
geosynthetics from a minimum 1-foot-thick layer. Equipment will not be allowed to operate
directly on the geosynthetics. A 1-foot-thick layer of topsoil will be used to complete the cap. The
top soils will only be nominally compacted, and will be scarified prior to revegetation. Restoration
of the wetland habitat will be performed in accordance with the Restoration Plan.
A primary design objective of this remedial alternative has been to facilitate restoration and
improvement of the existing wetlands while removing the potential for contact with the
hydrocarbon-impacted soils. The liner system provides separation, and the design grades are
intended to direct water within the catchment of the reservoir (approximately 11.5 acres) to
accumulate in the wetland complex. Seasonally, approximately 12.5 acre-feet of water will
accumulate within the new 6.5-acre wetland complex.
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Remediation at Reservoir 3 will impact existing wetlands, VPFS habitat, and sensitive plant
species within the remediation boundary. Impacts and restoration to ecological resources will be
detailed in the Restoration Plan.
Some settlement is anticipated (and considered desirable) after construction of the cap. The
various geosynthetic elements of the cap are capable of withstanding the likely strains that may be
imposed during settlement and are reinforced with a geogrid designed to limit excessive
settlement. The excavation plan is designed to provide some additional weight over the center of
the reservoir and encourage the greatest relative amount of settlement at that location. This is
intended to encourage water to pool towards the center of the reservoir. Settlement will be
monitored by three settlement monuments, as shown in Figure 43. One will be located as near to
the center of the reservoir as practical, a second will be installed over the cap towards the perimeter,
and a third will be installed locally on undisturbed ground. These monuments will consist of the
typical cap section but will be cast into concrete blocks approximately 12 inches on a side.
Settlement will be monitored as part of the MRP to ensure that sufficient grade is maintained to
provide adequate drainage and reduce excess ponding on top of the cap.
7.4.3 AOC #3 - Other Sticky Hydrocarbon Surface Expressions
There are an additional 12 areas affected by plastic hydrocarbon surface expressions. These are
shown in Figure 45. It is proposed to excavate these areas as described in Section 4.2, and backfill
them with common fill and 1 foot of topsoil at the surface. Several of these areas are adjacent to
or within the work areas for other remedial activities, such as Reservoir 5 and Reservoir 3. As a
practical matter, those sites will be excavated in conjunction with preparing the work areas for the
larger remedial activities.
The 12 locations comprise 5.90 acres and are estimated to generate approximately 28,700 cubic
yards of potentially hydrocarbon-impacted soil requiring offsite disposal. Backfilling the
excavations will require 19,200 cubic yards of common earth and 9,500 cubic yards of topsoil.
Impacts to waters/wetlands, VPFS habitat, and sensitive plant species communities will be detailed
in the Restoration Plan. Each of the areas will be restored and revegetated as specified in the
Restoration Plan.
7.4.4 AOC #4 - Arsenic
The proposed actions for the arsenic in the open space area between Reservoir 2 and the
southeastern development area include removal of the upper 1 to 3 feet (approximately 2,000 cubic
yards of soil) with elevated arsenic concentrations and other metals in excess of background
concentrations. The area has wetlands, VPFS habitat, and Congdon’s tarplant that would
temporarily be affected by the remediation activities (see Appendix K).
The removed soil will be placed within the proposed soil cap in the Northwest Operations Area.
Excavation areas will be backfilled with onsite borrow soil to blend with surrounding topography.
The impacted VPFS habitat, wetlands, and sensitive plant populations will be restored according
to the guidelines of the project Restoration Plan.
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7.5 OU #5 - SITE-WIDE GROUNDWATER
Monitored natural attenuation will be implemented using the same parameters and methods as
specified in the MRP (Appendix B). However, remediation will require abandonment of several
monitoring wells (Table 2). Replacement of wells needed for post-remediation monitoring will be
determined in consultation with the RWQCB, which will also approve a revised MRP. At a
minimum, monitoring groundwater for TPH and BTEX (consistent with MRP 93-120) will be
performed at the remaining perimeter monitoring wells MW-49, MW-50, MW-56, and SLOW-17,
and the offsite production wells 11Ea and 11Eb. Currently, monitoring is performed on a
semiannual basis. After three years, the RWQCB will evaluate the semiannual groundwater data
to determine if a reduction in the monitoring frequency is warranted.
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San Luis Obispo, California March 31, 2015
8.0 IMPACTS TO NATURAL RESOURCES AND MITIGATION
The remedial actions described in this RAP will ultimately reduce potential human health and
ecological risks. While these actions are being implemented, however, waters/wetlands, VPFS
habitat, and other ecological resources will be impacted. The anticipated areas of impact and
mitigation procedures will be summarized in the Restoration Plan. Actual impacts and proposed
restoration will be detailed in surveys, monitoring, and the Restoration Plan.
Final Remedial Action Plan
Chevron San Luis Obispo Tank Farm Page 67
San Luis Obispo, California March 31, 2015
9.0 LONG-TERM MAINTENANCE
Once the caps and other short-term remedial actions have been implemented, the long-term
monitoring and maintenance phase of site remediation and closure will begin. Long-term
monitoring is the remedial action for various groundwater impacts, as discussed in Section 4.1.
Long-term maintenance is specified to ensure that those actions taken under this plan (e.g.,
excavations, cap construction) continue to achieve their remedial objectives.
Remediation inspections will include excavation areas and constructed caps. The frequency of
inspections will be established in consultation with the RWQCB and other appropriate regulatory
agencies and will be included in the MRP. Monitoring of restoration areas will be in accordance
with the Restoration Plan.
Typical remediation area inspections will, at a minimum, look at the following:
• signs of erosion or burrowing by animals
• recurrence or new surface expressions of plastic hydrocarbon
• successful erosion control features
• integrity of fencing and other onsite ICs and ECs
• settlement
Most of these activities will be visual inspections by trained technicians or subject experts.
Settlement will be measured by properly trained technicians under the supervision of a surveyor
or civil engineer licensed to practice in the state of California. Settlement measurements will
monitor movement in the various caps to ensure that proper drainage is maintained so that excess
ponding does not occur on top of the caps.
Inspections will look for resurfacing of plastic hydrocarbon expressions at the excavation
locations, especially if material at depths greater than 5 feet was left in place. Inspections will also
include other areas of the site overlying impacted soils and will look for new surface expressions.
In either case, resurfaced material will be removed using the standards and protocols described in
this plan. Further recurrence of a surface expression will prompt evaluation and a focused remedial
action. A contingency plan will be prepared and submitted to RWQCB for review (the RWQCB
may solicit comments from other natural resource agencies, as appropriate) and approval prior to
the implementation of long-term monitoring to ensure that resurfaced materials will be addressed
upon discovery.
The degree to which settlement is considered unacceptable will vary between caps. It is expected
that significant settlement may occur at the Reservoir 3 cap. The geosynthetics are designed to
accept strains of up to 2 feet. The caps to be built for Reservoirs 5 and 7 are somewhat more
sensitive to settlement, in that it could compromise the void space available for groundwater to
occupy. These caps can accept settlements up to 1 foot, measured at the former reservoir centers
before remedial activity would need to be considered.
Final Remedial Action Plan
Chevron San Luis Obispo Tank Farm Page 68
San Luis Obispo, California March 31, 2015
The caps in future development areas are not expected to experience significant settlement prior
to subsequent construction activities. It is anticipated, however, that any structures built on these
caps will include careful geotechnical engineering that incorporates the limits and constraints of
the caps as described in Sections 7.1.2 and 7.3.
Over time, the caps may require maintenance. It is expected that this will be minor in nature and
would include activities such as repairing drainages or discouraging bioturbation. It may also be
necessary to reseed or replace topsoil if erosion is greater than expected or vegetation is slow to
establish itself. More significant repairs would be made as needed, and would be based on
observations made during the periodic inspections. This would include regrading if low spots were
to develop in caps other than Reservoir 3.
While Chevron is committed to ensuring the long-term maintenance of this project, the mechanism
for implementation has not yet been determined. Chevron may utilize its own forces or out-source
the work to a third party with experience in habitat maintenance. The specifics of implementing
long-term site maintenance will be developed in concert with the project stakeholders, including
the lead municipalities, to ensure the long-term success of the project.
Final Remedial Action Plan
Chevron San Luis Obispo Tank Farm Page 69
San Luis Obispo, California March 31, 2015
10.0 SCHEDULE
A preliminary project schedule is shown in Figure 47. It provides a high-level view of the
anticipated timeline of the principal project components.
The project schedule anticipates the FEIR to be certified complete in the third quarter of 2014.
Once the FEIR is certified, the RWQCB can approve the RAP and SLO County can approve and
issue the Conditional Use Permit for remediation and restoration.
At present, it is anticipated that three years will be necessary to complete all of the remedial
actions. This schedule may be lengthened due to mitigation measures, weather impacts, or other
constraints. The schedule anticipates that remedial construction will be completed near the middle
of 2018.
Final Remedial Action Plan
Chevron San Luis Obispo Tank Farm Page 70
San Luis Obispo, California March 31, 2015
REFERENCES
American Public Works Association, Southern California Chapter, 1997, “Standard Plans for
Public Works Construction,” BNI Building News.
Associated Transportation Engineer, November 9, 2007, Chevron San Luis Obispo Remediation
Project, Traffic and Circulation Study.
Avocet Environmental, Inc., March 15, 2007, Feasibility Study, Former San Luis Obispo Tank
Farm, 276 Tank Farm Road, San Luis Obispo, California.
Avocet Environmental, Inc., December 18, 2007, Remedial Action Plan, Former San Luis Obispo
Tank Farm, 276 Tank Farm Road, San Luis Obispo, California.
Avocet Environmental, Inc., January 26, 2009, Hydrology Study, Former San Luis Obispo Tank
Farm, 276 Tank Farm Road, San Luis Obispo, California.
BBL Sciences, December 12, 2005, Risk Management Summary, Former Unocal San Luis Obispo
Tank Farm, San Luis Obispo, California (Version 2.0).
California Department of Toxic Substances Control, Human and Ecological Risk Division
(HERD), May 15, 1998, HERD Ecological Risk Assessment Note Number 1,
http://www.dtsc.ca.gov/AssessingRisk/upload/econote1.pdf
California Department of Transportation, 2003, Caltrans Storm Water Quality Handbooks, Project
Planning and Design Guide, April 2003.
Cleath & Associates, 2002, Well Construction and Testing, Groundwater Exploration, San Luis
Obispo Tank Farm Property, San Luis Obispo, California, September 30, 2002.
City of San Luis Obispo, 2005, San Luis Obispo Airport Area Specific Plan, City of San Luis
Obispo Community Development Department, August 2005.
England Geosystem, Inc., November 1, 2000, Seep Evaluation Trenching Report, Unocal San Luis
Obispo Tank Farm, San Luis Obispo County.
England Geosystem, Inc., April 17, 2001, Limited Site Assessment, Former SLOCO Recycling
Center, Former San Luis Obispo Tank Farm, San Luis Obispo County, California.
England Geosystem, Inc., October 15, 2001, Supplemental Site Characterization, Unocal San Luis
Obispo Tank Farm, 276 Tank Farm Road, San Luis Obispo, California.
England, Shahin & Associates, May 11, 1994, Supplemental Ground Water Investigation, Unocal
Tank Farm Facility, 276 Tank Farm Road, San Luis Obispo, California.
Final Remedial Action Plan
Chevron San Luis Obispo Tank Farm Page 71
San Luis Obispo, California March 31, 2015
Fifield, J.S., 2004, Designing for Effective Sediment and Erosion Control on Construction Sites,
Forester Communications, Inc., Santa Barbara.
Frederick R.H., and J.F. Miller, 1979, Short Duration Rainfall Frequency Relations for California,
Proceedings from the Third Conference on Hydrometrology, August 20-24, 1979, page 67.
Goldman, S.J., K. Jackson, and T.A. Bursztynysky, 1986, Erosion and Sediment Control
Handbook, McGraw-Hill, New York.
ICBO, 1994, Uniform Building Code Volume 2, International Conference of Building Officials.
Koerner, R.M., 1990, Designing with Geosynthetics, Prentice Hall, New Jersey.
Marine Research Specialists, December 2013, Chevron Tank Farm Remediation and Development
Project Final Environmental Impact Report (FEIR).
McDaniel Lambert, Inc., 2013, Updated Human Health Risk Assessment for the San Luis Obispo
Tank Farm Property, Version 2.0, January 30, 2013.
Padre Associates, Inc., 2007a, Geotechnical Feasibility Study, Tank Farm Property Tank Farm
Remedial Action Project San Luis Obispo, San Luis Obispo County, California,
October 23, 2007
Padre Associates, Inc., 2007b, Project Execution Plan, December 20, 2007.
Prussing, G. F., L.C. Hampton, and C.F. Lienesch, 1926, San Luis Obispo and Stewart Tank Farm
Fires, April 7 to 11, 1926: Union Oil Company of California, Los Angeles, California,
Engineering Department Report Dated November 1, 1926.
Remediation Technology Panel (RTP), May 9, 2006, Remediation Technology Panel (RTP)
Assessment of Off-Site Migration and On-Site Surface Expressions of Hydrocarbons at the
San Luis Obispo Tank Farm Site, prepared by Dr. David Huntley, San Diego State
University; Dr. Paul Johnson, Arizona State University; and Dr. Kent Udell, University of
California at Berkeley. Ratified May 9, 2006.
Renard, K.G., 1997, Predicting Soil Erosion by Water: A Guide to Conservation Planning with
the Revised Soil Loss Equation (RUSLE), USDA Agricultural Handbook No. 703. U.S.
Department of Agriculture, Washington, DC.
Schroeder, P.R., T.S. Dozier, P.A. Zappi, B.M. McEnroe, J.W. Sjostrom, and R.L. Peyton,
September 1994, The Hydrologic Evaluation of Landfill Performance (HELP) Model:
Engineering documentation for Version 3, EPA/600/9-94, U.S. Environmental Protection
Agency Risk Reduction Engineering Laboratory, Cincinnati, Ohio.
Final Remedial Action Plan
Chevron San Luis Obispo Tank Farm Page 72
San Luis Obispo, California March 31, 2015
San Luis Obispo County, 2006, Private Sewage Disposal System, San Luis Obispo County
Department of Planning and Building Department, July 6, 2006
U.S. Department of Transportation, 2001, Urban Drainage Design Manual, Hydraulic Circular
No. 22, Second Edition, August 2001.
Viessman W., and G.L. Lewis, 1996, Introduction to Hydrology, Fourth Edition, Page183.
Tables
Table 1
Summary of Operable Units and Preferred Remedies
Chevron San Luis Obispo Tank Farm
San Luis Obispo, California
AOC #1 - LNAPL/BTEX-Impacted
Groundwater Natural Attenuation + ICs + LTM Vapor Barriers
Groundwater Use Restrictions
AOC #2 - Surface Soils Capping + ICs + ECs + LTM
Vapor Barriers
Use Restrictions
Notice of Subsurface Chemicals of Concern
Groundwater Use Restrictions
OU #2 - Reservoirs 5 & 7 - Capping + ICs + LTM Use Restrictions
OU #3 - Reservoir 4 - Capping/Excavation + ICs + ECs + LTM
Vapor Barriers
Use Restrictions
Notice of Subsurface Chemicals of Concern
AOC #1 - North Marsh Area Excavation + ICs + LTM Use Restrictions
AOC #2 - Reservoir 3 Capping + ICs + LTM Use Restrictions
AOC #3 - PPSH Areas Excavation + ICs + LTM Use Restrictions
AOC #4 - Arsenic Excavation + ICs + LTM Use Restrictions
OU #5 - Site-Wide Groundwater - Natural Attenuation + ICs + LTM Use Restrictions
Groundwater Use Restrictions
Notes:
BTEX = benzene, toluene, ethyl benzene, and total xylenes
ICs = institutional controls
LNAPL = light nonaqueous-phase liquid
LTM = long-term monitoring
PPSH = pliable plastic surface hydrocarbon
Institutional and engineering controls are briefly discussed in Section 3.0
OU #4 - Remaining Site-Wide
Surface and Subsurface Soils
Operable Unit (OU) Area of Concern (AOC) Preferred Remedy
OU #1 - Northwest Operations Area
Proposed Institutional and
Engineering Controls
Table 2
List of Active Monitoring Wells and
Wells Proposed for Abandonment
Chevron San Luis Obispo Tank Farm
San Luis Obispo, California
Active
Monitoring
Well ID
Northing
(feet)
Easting
(feet)
Ground
Elevation
(feet)
Total Depth
(feet)
Proposed for
Abandonment
11Ea 2,286,403.33 5,766,242.72 120.12
11Eb 2,285,788.14 5,765,801.69 118.48
11Ec 2,285,291.33 5,765,508.27 116.83
11Ed 2,284,934.66 5,765,842.84 120.62
11La 2,284,552.74 5,766,755.02 114.77
MW-17 2,286,370.00 5,770,908.56 142.51 20.0 X
MW-18 2,286,168.77 5,770,163.88 142.48 21.5 X
MW-19 2,285,775.94 5,769,634.88 138.72 21.0
MW-26 2,285,032.40 5,766,234.06 117.84 21.0
MW-27 2,285,626.38 5,766,432.64 119.38 22.5
MW-29 2,284,254.39 5,768,615.77 132.06 23.0
MW-35 2,284,544.36 5,769,095.02 132.93 30.0
MW-38 2,284,771.55 5,767,041.29 113.77 30.0
MW-39 2,284,782.44 5,766,583.53 114.57 30.0
MW-40 2,286,140.64 5,766,491.67 117.04 30.0
MW-41 2,286,496.67 5,766,672.93 118.48 30.0
MW-43 2,284,257.98 5,768,184.71 130.61 25.0
MW-45 2,284,500.98 5,767,405.38 127.51 31.0
MW-46 2,284,071.49 5,767,817.56 131.14 30.0
MW-47 2,284,997.98 5,766,065.13 118.12 100.0
MW-48D 2,285,438.75 5,766,297.58 119.40 40.0
MW-48S 2,285,438.75 5,766,297.58 119.50 20.0
MW-49 2,286,660.91 5,766,079.56 122.55 40.0
MW-50 2,286,893.20 5,766,084.77 121.40 40.0
MW-53D 2,285,863.52 5,766,440.08 118.00 40.0
MW-53S 2,285,863.52 5,766,440.08 118.20 20.0
MW-56 2,286,751.61 5,766,088.21 120.67 41.5
SLOW-12 2,286,835.65 5,766,153.13 120.39 15.0 X
SLOW-17 2,286,602.27 5,766,284.93 120.46 28.0
SLOW-18 2,286,728.07 5,766,212.88 120.21 26.0 X
Table 3
Estimated Borrow Source Quantities
Chevron San Luis Obispo Tank Farm
San Luis Obispo, California
Area Topsoil
(cy)
Common
Earth
(cy)
Gravel
(cy)
Offsite Cut
(cy)
Borrow Area - 1 9,000 27,200 0 0
Borrow Area - 2 20,700 0 0 0
Borrow Area - 3 16,900 33,750 0 0
Oxbow Borrow 2,800 25,500 0 0
Borrow Area - Flower Mound(1)0 268,000 82,000 73,700
Reservoir 5 & 7 Berms 0 71,600 0 0
Total 49,400 426,050 82,000 73,700
Notes:
(1) The Flower Mound borrow volume consists of onsite material only. Grading
will generate approximately 73,700 cy of material outside of the property
boundary.
cy = cubic yard
Table 4Estimated Remediation Construction QuantitiesChevron San Luis Obispo Tank FarmSan Luis Obispo, CaliforniaGrading Area(1)(sf)Work Area(2)(sf)Geotextile 12oz.(sf)Geomembrane(sf)Geogrid(sf) OU #1 - Northwest Operations Area323,300 323,300- - 53,400- - 280,300- - OU #2 - Reservoir 5340,239 453,190 15,300 12,500- 20,100 12,600 340,239- - OU #2 - Reservoir 7295,939 349,815 11,000 24,500- 39,000 11,000 160,460- - OU #3 - Reservoir 42,290,570 2,290,570- - 262,800- - 342,886- - OU #4 - North Marsh Area580,800 678,988 75,300 53,800- - 21,500- - - OU #4 - Reservoir 3300,161 581,436 26,700 5,100- 10,500 11,100 871,002 290,334 290,334 OU #4 - Remaining PPSH256,873155,860(3). 28,700 19,200- - 9,500- - - OU #4 - Arsenic43,560 56,628 2,675 3,300- - 1,650- - - Reservoir 2(4)518,400 518,400- - - - - - - - Access Roads204,700 204,700- - - 3,800- - - - Nursery100,000 100,000- - - 4,300- - - - Contractor Staging Area174,200 174,200- - - 4,300- - - - Borrow Area 2527,389 527,389- - 57,900 - - - - - - Total5,956,131 6,414,476 159,675 118,400 374,100 82,000 67,350 1,994,887 290,334 290,334Notes: cy = cubic yard OU = operable unit PPSH = pliable plastic surface hydrocarbon sf = square foot (1) The grading area is defined by the cut or fill boundary of any given excavation or cap. (2) The work area, which is the entire area affected by remediation activities, includes all of the area within the identified clear and grub line. (3) Some of the work area for Remaining PPSH has already been accounted for in the work areas corresponding to Reservoirs 5, 7, and 3. (4) Grading will involve approximately 38,000 cubic yards of berm material, with the anticipation that no or minimal materials will be imported or exported relative to this activity. Some small areas of petroleum expressions within the grading boundaries will be excavated; volume is included in OU #4.Topsoil(cy)Geosynthetics AreaEstimated AreasEstimated Impacted Soil Volumes(cy)Common Fill(cy)Structural Fill(cy)Gravel(cy)
Figures
SAN LUIS OBISPO
COUNTY AIRPORT
TANK FARM ROADHIGUERA STREETS:\GIS\1306_SLOTF-EMC_Work_Activities\1306.003_2013_Work_Activities\ArcMapDocuments\020_1306.003_Site_Location_Map.mxd\4/10/2014FIGURE 1
SITE LOCATION MAP
REMEDIAL ACTION PLAN
SAN LUIS OBISPO, CALIFORNIA
PREPARED FOR
CHEVRON EMC
SAN LUIS OBISPO, CALIFORNIA
APPROXIMATE
SCALE
0 2,000 4,0001,000
Feet
EXPLANATION
CITY OF SAN LUIS OBISPO
RESERVOIR 4
NORTHWEST
AREA
RESERVOIR
5
RESERVOIR
6
RESERVOIR
7
RESERVOIR
3
RESERVOIR
2
FORMER
RECYCLING
AREA
FIRE SCHOOL AREAEXISTING
BUILDINGS
TANK FARM ROAD
NORTH
MARSH
SAN LUIS OBISPO COUNTY
REGIONAL AIRPORT
TRAILER
PARK
FLOWER MOUND
Tank Farm CreekEastForkSan LuisObispoCreekSANTA FE ROADAcacia CreekS:\GIS\1306_SLOTF-EMC_Work_Activities\1306.003_2013_Work_Activities\ArcMapDocuments\023_1306.003_Site_Map.mxd\4/22/2013FIGURE 2
SITE MAP
REMEDIAL ACTION PLAN
SAN LUIS OBISPO TANK FARM
PREPARED FOR
CHEVRON EMC
SAN LUIS OBISPO, CALIFORNIA
EXPLANATION
PROJECT AREA BOUNDARY
APPROXIMATE
SCALE
FEET
0 500 1,000250
REFERENCE:
AERIAL PHOTOGRAPH DATED FEBRUARY 4, 2008.
ORIGINAL
BUILDING
ORIGINAL
BUILDING
EXISTING FIRE
WATER TANK
TANK FARM ROAD
FORMER FIRE
SCHOOL
LOCATION TRENCH USED BY THE
FORMER FIRE SCHOOL
FORMER PUMP
STATION
LOCATION
(REMOVED)
MAIN ACCESS
GATE
B-33
B-35
B-36
SLOW-18
MW-50
MW-56
SLOW-12
MW-49 ACCESS ROADAPPROXIMATE
LOCATION OF
EXISTING
SEPTIC TANK &
LEACH LINES 6" WATER8" RELIEF LINE8"8" BYPASS10"3"8"8"16"6"
16"16"16"8"16"
3"10"
8" RELIEF
10"
16"
LOCATION OF ABANDONED AND
DEMOLISHED FORMER HEATER
FORMER GASOLINE
AST LOCATION
EXISTING
OIL LINE "A"
4" GAS LINE
2" GAS LINE 2" GAS LINE REPORTED
TO BE ABANDONED
STORAGE
CONTAINER
APPROXIMATE LOCATION
OF EXISTING SEPTIC TANK
PADS FOR
FORMER FIRE
PUMPS
APPROXIMATE LOCATION
OF ABANDONED WATER
SUPPLY WELL No. 2
16" PIPE LINE
FOUNDATION OF FORMER
ELECTRICAL HOUSE
VAULTS
VAULTS
FORMER LINE
No. 2 TO SANTA
MARGARITA
APPROXIMATE LOCATION
OF ABANDONED 12" DIA.
WELL No. 1
APPROXIMATE LOCATION OF
FORMER 55,000 BBL ABOVE
GROUND TANK - AST 522
(DEMOLISHED BETWEEN
1959 AND 1965)
FORMER FIRE SCHOOL
AST LOCATIONS
APPROXIMATE LOCATION OF
FORMER 55,000 BBL ABOVE
GROUND TANK
(NOT REBUILT AFTER 1926 FIRE)
APPROXIMATE LOCATION OF
FORMER 55,000 BBL ABOVE
GROUND TANK - USED FOR
FIRE WATER STORAGE FROM
APPROXIMATELY 1994-2004
(REMOVED AUGUST 2000)
APPROXIMATE LOCATION OF FORMER
55,000 BBL ABOVE GROUND TANK
(REMOVED 1994)
LEACH FEILD
NEW MODULAR
OFFICE BUILDING
PETROLEUM
TESTING
LABORATORY
OPERATIONAL WATER SUPPLY
WELL (SUPPLIES NON-POTABLE
WATER TO SITE)
FOUNDATION OF
FORMER BOILER AND
TANK LOCATIONS
SCALE
0 80 160 FEETV:\1212_Padre-Chevron_SLOTF\1212.001_Remedial_Design\013_1212.001_Historical_Operations_Area.dwg\04/17/14N
FIGURE 3
NORTHWEST OPERATIONS AREA
HISTORICAL AND
CURRENT FEATURES
REMEDIAL ACTION PLAN
SAN LUIS OBISPO TANK FARM
PREPARED FOR
CHEVRON EMC
SAN LUIS OBISPO, CALIFORNIA
SITE PROPERTY BOUNDARY
TOPOGRAPHIC CONTOUR
FENCEX
LEGEND
125
EXISTING LIGHT POLE
FIRE HYDRANT
EXISTING MONITORING / PRODUCTION WELL
WATER LINE
DRAIN LINE
CRUDE OIL
GAS - CRUDE OIL
GAS - OIL
GAS
GASOLINE
REFERENCE:
1. AERIAL PHOTOGRAPH BY CENTRAL COAST AERIAL PMAPPING,
DATED MARCH 2, 2007.
2. TOPOGRAPHIC CONTOURS AND FEATURES PROVIDED BY EDA,
DATED JULY 2007.
NOTES:
1. FIGURE ONLY SHOWS THE PRINCIPAL HISTORIC
ELEMENTS OF THE OPERATIONS AREA. THE AERIAL
PHOTOGRAPH ILLUSTRATES THE CURRENT
CONDITIONS. THE HIGHLIGHTED ELEMENTS WERE
IN-PLACE PRIOR TO 1994 (WHEN PETROLEUM
OPERATIONS CEASED). SHADED ELEMENTS HAVE
BEEN DEMOLISHED OR DISMANTLED.
2. FIRE SCHOOL OPERATIONS WERE RELOCATED TO
THE RICHMOND REFINERY IN THE 1970'S.
3. THE PUMP HOUSE BUILDINGS WERE DEMOLISHED
AND REMOVED IN THE LATE 1990'S.
RESERVOIR 4
NORTHWEST
AREA
RESERVOIR
5
RESERVOIR
6
RESERVOIR
7
RESERVOIR
3
RESERVOIR
2
FORMER
RECYCLING
AREA
T A N K F A R M R O A D
NORTH
MARSH
EXISTING
STRUCTURES
AERIAL ELECTRICAL SERVICE (PG&E)
AERIAL ELECTRICAL SERVICE (PG&E)
AND TELECOMM SERVICE (ATT)
AERIAL ELECTRICAL SERVICE (PG&E)
AND TELECOMM SERVICE (ATT)
UNDERGROUND 4" DIA. H.P.
GAS SERVICE (THE GAS CO.)
UNDERGROUND ELECTRICAL SERVICE (PG&E)
SEWER LIFT
STATION
S:\GIS\1212_Chevron_Padre_SLOTF\001_Remedial_Design\ArcMapDocuments\005_1212.001_Existing_Utilities_Easements.mxd\12/17/07FIGURE 4
EXISTING UTILITIES
REMEDIAL ACTION PLAN
SAN LUIS OBISPO TANK FARM
PREPARED FOR
CHEVRON EMC
SAN LUIS OBISPO, CALIFORNIA
APPROXIMATE
SCALE
FEET
0 500 1,000250
EXPLANATION
PROJECT AREA BOUNDARY
OVERHEAD AT&T LINES
OVERHEAD PG&E LINES
PG&E UNDERGROUND LINE
NATURAL GAS LINE
EXISTING SEWER ALIGNMENT
RESERVOIR 4
NORTHWEST
AREA
RESERVOIR
5
RESERVOIR
6
RESERVOIR
7
RESERVOIR
3
RESERVOIR
2
FORMER
RECYCLING
AREA
T A N K F A R M R O A D
NORTH
MARSH
OCCUPIED
OFFICE
STUCTURES
FORMER FIRE SCHOOL LOCATION
S:\GIS\1306_SLOTF-EMC_Work_Activities\1306.003_2013_Work_Activities\ArcMapDocuments\024_1306.003_Chevron_Pipelines.mxd\4/11/2014FIGURE 5
CHEVRON PIPELINES
REMEDIAL ACTION PLAN
SAN LUIS OBISPO TANK FARM
PREPARED FOR
CHEVRON EMC
SAN LUIS OBISPO, CALIFORNIA
EXPLANATION
PROJECT AREA BOUNDARY
CRUDE OIL PIPELINES
OTHER UNDERGROUND PIPELINES
APPROXIMATE
SCALE
FEET
0 500 1,000250
SEE FIGURE 6
FOR DETAIL
NOTES:
1) LEACH LINES AND DRAIN LINES ARE SHOWN AS
CRUDE OIL LINES ON THIS FIGURE FOR CLARITY.
SIMILIARLY FOAMITE LINES ARE SHOWN AS WATER
LINES DUE TO THEIR SIMILIAR FUNCTIONS DURING
OPERATIONS.
2) UTILITY LOCATIONS ARE APPROXIMATE. ACTUAL
LOCATION TO BE VERIFIED IN THE FIELD.
3) PORTIONS OF CRUDE OIL AND WATER LINES
EXTENDING ALONG THE NORTH SIDE OF TANK
FARM ROAD WERE REMOVED AS PART OF THE
CITY'S SEWER PROJECT IN 2008.
SUMMARY OF PIPELINE LENGTHS
LENGTH (FEET)
25,125
258
914
38,263
9,177
TYPES
CRUDE OIL
LEACH LINE
(SANITATION)
DRAIN LINES
WATER LINE
FOAMITE
REFERENCES:
1. AERIAL PHOTOGRAPH DATED FEBRUARY 4, 2008
2. GENERAL ARRANGEMENT SAN LUIS OBISPO TANK FARM, PRODUCERS PIPELINE,
UNION OIL COMPANY OF CALIFORNIA, DRAWING No. UNKNOWN, DATED APRIL 3, 1950.
GENERAL ARRANGEMENT SAN LUIS OBISPO TANK FARM NORTHERN DIVISION
PIPELINE UNION OIL COMPANY OF CALIFORNIA, DRAWING No. D2A180, DATED JULY 30, 1981.
ORIGINAL
BUILDING
ORIGINAL
BUILDING
TANK FARM ROADSTOPFORMER FIRE
SCHOOL
LOCATION TRENCH USED BY THE
FORMER FIRE SCHOOL
FOUNDATION OF
FORMER BOILER AND
TANK LOCATIONS
FORMER PUMP
STATION
LOCATION
(REMOVED)
MAIN ACCESS
GATE ACCESS ROADAPPROXIMATE
LOCATION OF
EXISTING
SEPTIC TANK &
LEACH LINES
EXISTING
OIL LINE "A"
4" GAS LINE
2" GAS LINE
STORAGE
CONTAINER
APPROXIMATE LOCATION
OF EXISTING SEPTIC TANK
PADS FOR
FORMER FIRE
PUMPS
16" PIPE LINE
VAULTS
VAULTS
FORMER LINE
No. 2 TO SANTA
MARGARITA
LEACH FEILD
OPERATIONAL WATER
SUPPLY WELL (SUPPLIES
NON-POTABLE WATER TO
SITE)
NEW MODULAR
OFFICE BUILDING
PETROLEUM
TESTING
LABORATORY
6" WATER8" RELIEF LINE8"8" BYPASS10"3"8"8"16"6"
16"16"16"8"16"
3"10"
8" RELIEF
10"
16"
LOCATION OF ABANDONED AND
DEMOLISHED FORMER HEATER
FORMER GASOLINE
AST LOCATION
2" GAS LINE REPORTED
TO BE ABANDONED
FOUNDATION OF FORMER
ELECTRICAL HOUSE
LEACH FEILD
APPROXIMATE
LOCATION OF
EXISTING
SEPTIC TANK &
LEACH LINES
APPROXIMATE
LOCATION OF
EXISTING PVC
WATER LINE
SCALE
0 80 160 FEETV:\1212_Padre-Chevron_SLOTF\1212.001_Remedial_Design\026_1212.001_Detail_Chevron_Pipelines_NW_Ops_Area.dwg\04/10/14N
FIGURE 6
DETAIL PLAN OF CHEVRON PIPELINES
IN NORTHWEST OPERATIONS AREA
REMEDIAL ACTION PLAN
SAN LUIS OBISPO TANK FARM
PREPARED FOR
CHEVRON EMC
SAN LUIS OBISPO, CALIFORNIA
SITE PROPERTY BOUNDARY
TOPOGRAPHIC CONTOUR
FENCEX
LEGEND
125
WATER LINE
DRAIN LINE
CRUDE OIL
GAS - CRUDE OIL
GAS - OIL
GAS
GASOLINE
REFERENCES:
1. AERIAL PHOTOGRAPH BY CENTRAL COAST AERIAL MAPPING.
DATED MARCH 2, 2007
2. TOPOGRAPHIC CONTOURS AND FEATURES PROVIDED BY EDA, INC.
DATED JULY 2007.
LEACH LINE
FOAMITE LINE
SUMMARY OF PIPELINE LENGTHS IN
NORTHWEST OPERATIONS AREA
TYPES LENGTH (FEET)
CRUDE OIL
LEACH
DRAIN
WATER
FOAMITE
4,327
258
914
4,898
1,121
RESERVOIR 4
NORTHWEST
AREA
RESERVOIR
5
RESERVOIR
6
RESERVOIR
7
RESERVOIR
3
RESERVOIR
2
FORMER
RECYCLING
AREA
16.85 ACRES
19.13 ACRES
258.19 ACRES
30.65 ACRES
15.18 ACRESS:\GIS\1306_SLOTF-EMC_Work_Activities\1306.003_2013_Work_Activities\ArcMapDocuments\025_1306.003_Existing_SLO_County_Land_Use_Plan.mxd\4/28/2013FIGURE 7
EXISTING SAN LUIS OBISPO COUNTY
LAND USE PLAN
REMEDIAL ACTION PLAN
SAN LUIS OBISPO TANK FARM
PREPARED FOR
CHEVRON EMC
SAN LUIS OBISPO, CALIFORNIA
APPROXIMATE
SCALE
FEET
0 500 1,000250
EXPLANATION
PROJECT AREA BOUNDARY
RESIDENTIAL
AGRICULTURAL
COMMERCIAL SERVICES
INDUSTRIAL
PUBLIC FACILITY
RECREATION
REFERENCE:
AERIAL PHOTOGRAPH DATED FEBRUARY 2, 2008
RESERVOIR 4
NORTHWEST
AREA
RESERVOIR
5
RESERVOIR
6
RESERVOIR
7
RESERVOIR
3
RESERVOIR
2
FORMER
RECYCLING
AREA
295.90 ACRES
7.8 ACRES
2.3
ACRES13.6 ACRES
COLLECTOR ROAD
UNOCAL COLLECTOR ROADS
A
N
T
A
F
E
R
O
A
D
(
E
X
T
E
N
S
I
O
N
)
18.2 ACRES
2.2 ACRES
REFERENCE: AERIAL PHOTOGRAPH
DATED FEBRUARY 4, 2008.
SOURCE: AIRPORT AREA SPECIFIC PLAN,
SAN LUIS OBISPO, JANUARY 2005
EXPLANATION
PROJECT AREA BOUNDARY
RESIDENTIAL
BUSINESS PARK
SERVICE & MANUFACTURING
PUBLIC
OPEN SPACE
APPROXIMATE
SCALE
FEET
0 500 1,000250S:\GIS\1306_SLOTF-EMC_Work_Activities\1306.003_2013_Work_Activities\ArcMapDocuments\026_1306.003_City_SLO_AASP_Land_Use_Plan.mxd\5/6/2013FIGURE 8
CITY OF
SAN LUIS OBISPO
AASP LAND USE PLAN
REMEDIAL ACTION PLAN
SAN LUIS OBISPO TANK FARM
PREPARED FOR
CHEVRON EMC
SAN LUIS OBISPO, CALIFORNIA
PROPOSED ROAD
RESERVOIR 4
NORTHWEST
AREA
RESERVOIR
5
RESERVOIR
6
RESERVOIR
7
RESERVOIR
3
RESERVOIR
2
FORMER
RECYCLING
AREA
S:\GIS\1306_SLOTF-EMC_Work_Activities\1306.003_2013_Work_Activities\ArcMapDocuments\029_1306.003_Constraints_Proposed_SLO_Land_Use.mxd\8/8/2014FIGURE 9
CONSTRAINTS TO THE
PROPOSED CITY OF SAN LUIS OBISPO
LAND USE PLAN
REMEDIAL ACTION PLAN
SAN LUIS OBISPO TANK FARM
PREPARED FOR
CHEVRON EMC
SAN LUIS OBISPO, CALIFORNIA
REFERENCE:
AERIAL DATED FEBRUARY 4, 2008.
SOURCE: AIRPORT AREA SPECIFIC PLAN, SAN LUIS OBISPO. DATED: JANUARY 2005
APPROXIMATE
SCALE
FEET
0 500 1,000250
EXPLANATION
RESIDENTIAL
BUSINESS PARK
SERVICE & MANUFACTURING
PUBLIC
OPEN SPACE
LAND USE
RUNWAY ADDITION
RUNWAY PROTECTION
S-1a
S-1b
S-1c
100 YEAR FLOODPLAIN
AVIATION SAFETY ZONES
PROJECT AREA BOUNDARY
5 ACRES
274 ACRES
15 ACRES
5 ACRES 5 ACRES
4 ACRES
21 ACRES
1 ACRE
2 ACRES
8 ACRES
COLLECTOR ROAD
S
A
N
T
A
F
E
R
O
A
D
(
E
X
T
E
N
S
I
O
N
)S:\GIS\1306_SLOTF-EMC_Work_Activities\1306.003_2013_Work_Activities\ArcMapDocuments\038_1306.003_Proposed_Land_Use.mxd\5/6/2013FIGURE 10
PROPOSED LAND USE CONCEPT
REMEDIAL ACTION PLAN
SAN LUIS OBISPO TANK FARM
PREPARED FOR
CHEVRON EMC
SAN LUIS OBISPO, CALIFORNIA
REFERENCE:
AERIAL PHOTOGRAPH DATED FEBRUARY 4, 2008.
EXPLANATION
PROJECT AREA BOUNDARY
BUSINESS PARK
SERVICE & MANUFACTURING
RECREATION
OPEN SPACE
APPROXIMATE
SCALE
FEET
0 500 1,000250
V:\1306_SLOTF_EMC_Work_Activities\1306.003_2013_Work_Activities\006_1306.003_Hydrology_Map.ai\04/28/13Small Tributary CreekTANK FARM ROADDESIGN POINT ADESIGN POINT ADESIGN POINT B2-30” DIAMETER2-30” DIAMETERCMP CULVERTSCMP CULVERTSB5,476AcresA485AcresEXPLANATIONFLOW PATHHYDROLOGIC BOUNDARYCLOSED CATCHMENTSSITEAcacia Creek2-30” DIAMETERCMP CULVERTSBOX CULVERTSBOX CULVERTSBOX CULVERTS2-30” DIAMETER2-30” DIAMETERCMP CULVERTSCMP CULVERTS2-30” DIAMETERCMP CULVERTSCLOSED CATCHMENTSCLOSED CATCHMENTSAPPROXIMATELY 150 Ac OFAPPROXIMATELY 150 Ac OFTANK FARM DISCHARGE OFFSITETANK FARM DISCHARGE OFFSITEAPPROXIMATELY 150 Ac OFTANK FARM DISCHARGE OFFSITEOrcutt CreekOrcutt CreekEast Fo r k S a n Luis Obispo CreekTank Farm Creek02,0004,000 FEETAPPROXIMATESCALENFIGURE 11PREPARED FORCHEVRON EMCSAN LUIS OBISPO, CALIFORNIAREMEDIAL ACTION PLANSAN LUIS OBISPO TANK FARMHYDROLOGY MAPREFERENCE:REFERENCE:7.5 MINUTE U.S.G.S. TOPOGRAPHIC MAPS OF7.5 MINUTE U.S.G.S. TOPOGRAPHIC MAPS OFARROYO GRANDE, LOPEZ MOUNTAIN, PISMO BEACH,ARROYO GRANDE, LOPEZ MOUNTAIN, PISMO BEACH,AND SAN LUIS OBISPO, CALIFORNIA.AND SAN LUIS OBISPO, CALIFORNIA.REFERENCE:7.5 MINUTE U.S.G.S. TOPOGRAPHIC MAPS OFARROYO GRANDE, LOPEZ MOUNTAIN, PISMO BEACH,AND SAN LUIS OBISPO, CALIFORNIA.
ıôóıôóıôóıôóıôóıôóıôóıôóıôóıôóıôóıôóıôóıôóıôóıôóıôóıôóıôóıôóıôóıôóıôóıôóıôóıôóıôóıôóıôóıôóıôóıôóıôóıôóıôóıôóıôóıôóıôóRESERVOIR 4NORTHWESTAREARESERVOIR5RESERVOIR6RESERVOIR7RESERVOIR3RESERVOIR2FORMERRECYCLINGAREAS:\GIS\1306_SLOTF-EMC_Work_Activities\1306.004_SLOTF_2014_Support-EMC\ArcMapDocuments\002_1306.004_Wetlands_Fairy_Shrimp_Rare_Plant.mxd\12/9/2014FIGURE 12WETLANDS, FAIRY SHRIMP, ANDRARE PLANT HABITATSREMEDIAL ACTION PLANSAN LUIS OBISPO TANK FARMPREPARED FORCHEVRON EMCSAN LUIS OBISPO, CALIFORNIA05001,000250FeetApproximateScaleSOURCE: BIOLOGICAL RESOURCES MAPPING CONDUCTED BYPADRE AND WSP. FIELD STUDIES PERFORMED 2008.REFERENCE: AERIAL PHOTOGRAPH BY CENTRAL COAST AERIAL MAPPING.DATED MARCH 2, 2007EXPLANATIONSITE PROPERTY BOUNDARYıôóSOUTHERN CALIFORNIA WALNUTHOOVER'S BUTTON CELERYPURPLE NEEDLEGRASS GRASSLANDSLO (CAMBRIA) MORNING GLORYSLO MORNING GLORY (2003 SURVEY)SLO OWL'S CLOVERSLO SERPENTINE DUDLEYACONGDON'S TARPLANTDELINEATED WETLAND (SEE NOTE 1)PROTECTED FAIRY SHRIMPPRESENT (32.56 ACRES)PROTECTED FAIRY SHRIMPNOT PRESENT (71.80 ACRES)NOTE:THE WATERS OF THE U.S., INCLUDING WETLANDSUNDER US FEDERAL JURISDICTION SHOWN IN THISFIGURE WERE IDENTIFIED AND DELINEATEDCONSISTENT WITH DEFINITIONS OF WATERS OF THEUS PROVIDED AT 33 CFR 328.3 (A) (1-8) AND 33 CFR328.4 (B). FIELD DELINEATION PROTOCOLS FOLLOWTHE 1987 UPDATED AND ONLINE VERSION OF THEU.S, ARMY CORPS OF ENGINEERS WETLANDSDELINEATION MANUAL
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RESERVOIR 4
NORTHWEST
AREA
RESERVOIR
5
RESERVOIR
6
RESERVOIR
7
RESERVOIR
3
RESERVOIR
2
FORMER
RECYCLING
AREA
BETITA
PROPERTY
801 mg/kg
1,151 mg/kg
488 mg/kg
WETLANDS IMPACTED BY
ASPHALTIC CRUST
T-8-0.5
T-2-0.5
T-17-0.5
S:\GIS\1306_SLOTF-EMC_Work_Activities\1306.003_2013_Work_Activities\ArcMapDocuments\031_1306.003_Summary_Environmental_Impacts.mxd\4/28/2013FIGURE 13
SUMMARY OF ENVIRONMENTAL IMPACTS
REMEDIAL ACTION PLAN
SAN LUIS OBISPO TANK FARM
PREPARED FOR
CHEVRON EMC
SAN LUIS OBISPO, CALIFORNIA05001,000250
Feet
Approximate
Scale
EXPLANATION
TPH IN SOIL > 100 mg/kg
EXTENT OF BTEX
LIQUID CRUDE OIL. CAPABLE OF GENERATING
"FREE" DROPLETS OF OIL. (EVALUATED FOR
REMEDIATION IN FEASIBILITY STUDY)
PLIABLE, HIGHLY WEATHERED CRUDE OIL.
EVIDENCE OF RECENT PLASTIC FLOW.
(EVALUATED FOR REMEDIATION IN
FEASIBILITY STUDY)
SOLID, FORMER CRUDE OIL
PLIABLE, HIGHLY WEATHERED CRUDE OIL.
NO EVIDENCE OF PLASTIC FLOW
LNAPL OCCURANCE
PROJECT AREA BOUNDARY
TPH IN SOIL > 1,000 mg/kg
!(SOIL SAMPLE SHOWING LEAD
CONCENTRATION IN mg/kg
REFERENCE: AERIAL PHOTOGRAPH DATED FEBRUARY 4, 2008.
AREA OF ASENIC IMPACT
(EVALUATED FOR REMEDIATION
IN THE FEASIBILITY STUDY)
AREA OF ARSENIC IMPACT
RESERVOIR 4NW OPERATIONSAREARESERVOIR5RESERVOIR6RESERVOIR7RESERVOIR3RESERVOIR2FORMERRECYCLINGAREAOPERABLE UNIT #4SURFACE SOILSOPERABLE UNIT #3OPERABLE UNIT #2OPERABLE UNIT #1OPERABLE UNIT #5SITE-WIDE GROUNDWATER(OUTSIDE OU#1)OU #1 AOCsAOC-1 GROUNDWATERAOC-2 SOILSOU #4 AOC 1NORTH MARSHOU #4 AOC 2RESERVOIR 3OU #4 AOC 3OTHER PLASTICHYDROCARBONSURFACE EXPRESSIONSOU #4 AOC 3OTHER PLASTICHYDROCARBONSURFACE EXPRESSIONSOU #4 AOC 3OTHER PLASTICHYDROCARBONSURFACE EXPRESSIONSS:\GIS\1306_SLOTF-EMC_Work_Activities\1306.004_SLOTF_2014_Support-EMC\ArcMapDocuments\003_1306.004_Overview_of_Operable_Units.mxd\11/20/2014FIGURE 14OVERVIEW OF OPERABLE UNITSREMEDIAL ACTION PLANSAN LUIS OBISPO TANK FARMPREPARED FORCHEVRON EMCSAN LUIS OBISPO, CALIFORNIAAPPROXIMATESCALEFEET05001,000250REFERENCE: AERIAL PHOTOGRAPH DATED FEBRUARY 4, 2008.EXPLANATIONLIQUID CRUDE OIL. CAPABLE OF GENERATING"FREE" DROPLETS OF OIL.PLIABLE, HIGHLY WEATHERED CRUDE OIL.EVIDENCE OF RECENT PLASTIC FLOW.PROJECT AREA BOUNDARYAREA OF CONCERN (AOC)PLIABLE, HIGHLY WEATHERED CRUDE OIL.NO EVIDENCE OF PLASTIC FLOWFEDERAL AND STATE DELINEATED WETLANDSOPERABLE UNIT BOUNDARY (OU)EXTENT OF BTEX IN LNAPLOU #4 AOC 4ARSENICEASTERN DEVELOPMENT AREAEASTERN DEVELOPMENT AREADEVELOPMENT AREASRECREATION/PUBLIC FACILITYSERVICE AND MANUFACTURINGBUSINESS PARKROAD RIGHT-OF-WAYEASTERN DEVELOPMENT AREA
RESERVOIR 4
NORTHWEST
AREA
RESERVOIR
5
RESERVOIR
6
RESERVOIR
7
RESERVOIR
3
RESERVOIR
2
FORMER
RECYCLING
AREA
T A N K F A R M R O A D
NORTH
MARSH
PROPOSED STOCKPILE LOCATION
7.41 AC
239,000 CY AT 20' AVERAGE HEIGHT
PROVIDE SILT FENCING AND
EROSION CONTROL ALONG
CREEK EDGE
ON SITE ACCESS TO
STOCKPILE AREA
AT THIS LOCATION
SECONDARY STOCKPILE LOCATION
(APPROXIMATELY 1 AC/±15,000 CY)S:\GIS\1306_SLOTF-EMC_Work_Activities\1306.003_2013_Work_Activities\ArcMapDocuments\033_1306.003_Proposed_Impacted_Soil_Stockpile_Location.mxd\4/28/2013FIGURE 15
PROPOSED IMPACTED SOIL
STOCKPILE LOCATIONS
REMEDIAL ACTION PLAN
SAN LUIS OBISPO TANK FARM
PREPARED FOR
CHEVRON EMC
SAN LUIS OBISPO, CALIFORNIA
APPROXIMATE
SCALE
FEET
0 500 1,000250
EXPLANATION
PROJECT AREA BOUNDARY
REFERENCE:
AERIAL PHOTOGRAPH DATED FEBRUARY 4, 2008.
NOTES:
1. THE STOCKPILE WILL ONLY BE USED IN THE EVENT
OFF-SITE TRUCK TRIPS ARE LIMITED, BUT
EXCAVATION OF IMPACTED SOILS NEEDS TO
BE COMPLETED AS QUICKLY AS POSSIBLE.
2. STOCKPILING WILL OCCUR AFTER
BUILDING DEMOLITION, PIPELINE
ABANDONMENT AND GENERAL CLEAN-UP,
BUT BEFORE CONSTRUCTION OF THE CAP.
3. STOCKPILED MATERIALS WILL BE REMOVED
PRIOR TO CAP CONSTRUCTION.
CONFIRMATION SAMPLING WILL NOT
BE NECESSARY.
RESERVOIR 4
NORTHWEST
AREA
RESERVOIR
5
RESERVOIR
6
RESERVOIR
7
RESERVOIR
3
RESERVOIR
2
FORMER
RECYCLING
AREA
T A N K F A R M R O A D
NORTH
MARSH
REPORTED HISTORIC
DISPOSAL AREA
GROSS AREA 1.57 AC
BORROW No. 1
GROSS AREA 8.6 AC
COMMON EARTH 27,200 CY
TOPSOIL 9,000 CY
RESERVOIR 5BORROW BERM
COMMON EARTH 38,800 CY
BORROW No. 3
EXISTING WETLANDS 6.4 AC
COMMON EARTH 33,750 CY
TOPSOIL 16,900 CY RESERVOIR 7BORROW BERM
COMMON EARTH 32,800 CY
BORROW No. 2
GROSS AREA 8.5 AC
TOPSOIL 20,700 CY
FLOWER MOUND
GROSS AREA 25 AC
COMMON EARTH 268.000 CY
GRAVEL 82,000 CY
OFF-SITE GRADING
GROSS AREA 4.1 AC
COMMON EARTH 73,660 CY
OXBOW BORROW
COMMON EARTH 25,500 CY
TOP SOIL 2800 CYS:\GIS\1306_SLOTF-EMC_Work_Activities\1306.003_2013_Work_Activities\ArcMapDocuments\034_1306.003_Borrow_Source_Location_Map.mxd\8/8/2014FIGURE 16
BORROW SOURCE LOCATION MAP
REMEDIAL ACTION PLAN
SAN LUIS OBISPO TANK FARM
PREPARED FOR
CHEVRON EMC
SAN LUIS OBISPO, CALIFORNIA
APPROXIMATE
SCALE
FEET
0 500 1,000250
REFERENCE:
AERIAL PHOTOGRAPH DATED FEBRUARY 4, 2008.
NOTE:
NEW WETLANDS ASSUME THAT THE ENTIRE
BORROW AREA IS USED TO CREATE NEW
HABITAT. THE ACREAGE LISTED IS THE
GROSS AREA LESS ANY PRE-EXISTING
WETLANDS.
EXPLANATION
BORROW AREAS
DISPOSAL AREA
SITE BOUNDARY
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
RESERVOIR 4
NORTHWEST
AREA
RESERVOIR
5
RESERVOIR
6
RESERVOIR
7
RESERVOIR
3
RESERVOIR
2
FORMER
RECYCLING
AREA
T A N K F A R M R O A D
NORTH
MARSH
EXISTING WATER
SUPPLY WELL
SUGGESTED
CONTRACTOR
WATER TANK
LOCATION
ACCESS GATE
IMPROVED ENTRANCE
AND NEW GATE
EXISTING GATE
ELECTRICITY AND TELEPHONE
AVAILABLE FROM OVERHEAD
SERVICE HERE
PRIMARY STAGING AREA INCLUDING
CONTRACTORS SUPPORT TRAILERS
AND EQUIPMENT MAINTENANCE YARD
!(!(!(!(WELL No. 2
WELL No. 3
WELL No. 1
OU#3 AND FLOWER MOUND
INTEGRATED DISTURBANCE AREA
TEMPORARY
WATERLINE
J-STANDPROTECT TEMPORARY
WATERLINE AT ENTRANCE
S:\GIS\1306_SLOTF-EMC_Work_Activities\1306.003_2013_Work_Activities\ArcMapDocuments\035_1306.003_Work_Areas_Staging_Areas_Access.mxd\8/13/2014FIGURE 17
PROPOSED WORK AREAS,
STAGING AREAS, AND SITE ACCESS
REMEDIAL ACTION PLAN
SAN LUIS OBISPO TANK FARM
PREPARED FOR
CHEVRON EMC
SAN LUIS OBISPO, CALIFORNIA
APPROXIMATE
SCALE
FEET
0 500 1,000250REFERENCE:
AERIAL PHOTOGRAPH BY COASTAL AERIAL MAPPING
DATED: 03/02/2007
NOTES:
1. PRIMARY STAGING AREA WILL BE
LOCATED AT THE FORMER RECYCLING
AREA TO TAKE ADVANTAGE OF EXISTING
PAVEMENT, ELECTRICAL, AND TELEPHONE
SERVICES.
2. ACCESS ROUTES WILL, TO THE EXTENT
PRACTICAL, USE EXISTING TRAILS. ROUTES
WILL BE WIDENED, AS NECESSARY, TO
SAFELY ACCOMODATE TWO-WAY TRAFFIC.
3. CONTRACTOR MAY SUGGEST
ALTERNATIVE ROUTES, ESPECIALLY IF ONE-
WAY TRAFFIC WILL PROVIDE SAFER
ACCESS. ALTERNATIVE ROUTES MAY NOT
CAUSE ADDITIONAL IMPACTS TO
PROTECTED OR SENSITIVE HABITAT NOT
OTHERWISE DESCRIBED FOR THIS
PROJECT.
4. CONSTRUCTION WATER MAY BE
OBTAINED FROM THE EXISTING WATER
SUPPLY WELL.
5. ONSITE WATER FROM THE EXISTING
WELLS ARE NOT POTABLE. CONTRACTOR
WILL SUPPLY BOTTLED WATER FOR
POTABLE USES.
6. CONTRACTOR WILL PROVIDE PORTABLE
SANITATION FACILITIES AT STAGING AND
WORK AREAS, AS NEEDED.
7. WELL Nos. 1, 2, AND 3 ARE
CONSTRUCTED BUT ARE NOT EQUIPED
WITH PUMPS OR OTHER ANCILLARY
PRODUCTION EQUIPMENT. THEY MAY BE
USED TO SUPPLY CONSTRUCTION WATER,
BUT THE CONTRACTOR WILL NEED TO
SUPPLY THE EQUIPMENT, POWER, AND
TEMPORARY PIPELINES NECESSARY TO
BRING THEM INTO SERVICE.
8. THE WORK AREA FOR OU#3 IS
CONTIGUOUS WITH THE DISTURBANCE
AREA FOR THE FLOWER MOUND BORROW
AND GRADING. AS SUCH, THEY ARE
SHOWN AS A SINGLE AREA.
EXPLANATION
PROJECT AREA BOUNDARY
ACCESS ROUTE
BORROW AREAS
WETLANDS
WETLANDS IMPACTED
STAGING AREA
WORK AREA
!!?!!?!!?RESERVOIR 4RESERVOIR5RESERVOIR6RESERVOIR7RESERVOIR3RESERVOIR2T A N K F A R M R O A DNORTHMARSHFLOWERMOUNDSAN LUIS OBISPOCOUNTY AIRPORTS A N T A F E R O A DCONSTRUCTION DEBRIS PILESREMOVE FILL DISPOSALFORMER PIPELINE VAULTDEMOLISH AND BACKFILLHISTORIC WATER WELLLOCATE AND ABANDONIF NECESSARYHISTORIC WATER WELLSLOCATE AND ABANDONIF NECESSARYS:\GIS\1306_SLOTF-EMC_Work_Activities\1306.003_2013_Work_Activities\ArcMapDocuments\036_1306.003_Miscellaneous_Clean-Up_Areas.mxd\4/30/2013FIGURE 19MISCELLANEOUS CLEANUP AREASREMEDIAL ACTION PLANSAN LUIS OBISPO TANK FARMPREPARED FORCHEVRON EMCSAN LUIS OBISPO, CALIFORNIAEXPLANATIONPROJECT AREA BOUNDARYAPPROXIMATESCALEFEET05001,000250REFERENCE:AERIAL PHOTOGRAPH DATED FEBRUARY 4, 2008.
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AREA
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RECYCLING
AREA
EW-1
B-57
B-36
B-35
B-33
11La
11Ed
11Eb
11Ea
OMW-6
OEW-2
TMW-9
TMW-8
MW-56
MW-47
MW-46
MW-45
MW-44
MW-43
MW-41
MW-40
MW-39 MW-38
MW-37
MW-35
MW-32
MW-29
MW-27
MW-26
MW-19
MW-18
MW-17
MW-12
MW-11
MW-50
MW-49
MW-53SMW-53D
MW-48SMW-48D
SLOW-12
SLOW-18/BIV-25
SLOW-17/BIV-24
11Ec
SLOW-16/BIV-30
OMW-2
OMW-7
S:\GIS\1306_SLOTF-EMC_Work_Activities\1306.003_2013_Work_Activities\ArcMapDocuments\037_1306.003_GW_Monitoring_Network_Modifications_.mxd\4/17/2014FIGURE 20
MONITORING WELL NETWORK
MODIFICATIONS
REMEDIAL ACTION PLAN
SAN LUIS OBISPO TANK FARM
PREPARED FOR
CHEVRON EMC
SAN LUIS OBISPO, CALIFORNIA
EXPLANATION
APPROXIMATE
SCALE
FEET
0 500 1,000250
PROJECT AREA BOUNDARY
WELL TO BE ABANDONED DURING REMEDIATION!B
GROUNDWATER MONITORING WELL LOCATION
INCLUDED IN SEMI-ANNUAL MONITORING
PROGRAM!(!(REFERENCE: AERIAL PHOTOGRAPH
DATED 2008
GROUNDWATER MONITORING WELL LOCATION!(
6" WATER8" RELIEF LINE8"8" BYPASS10"3"8"8"16"6"
16"16"16"8"16"
3"10"
8" RELIEF
10"
16"
BUILDING BUILDING
BUILDINGGUARD/OFFICE
BUILDING
TANK FARM ROADSTOPFORMER
FIRE
TRENCH)
FORMER BOILER AND
TANK LOCATIONS
FORMER PUMP
STATION FOUNDATION
B-33
B-35
B-36
SLOW-18
MW-50
MW-56
SLOW-12
MW-49 ACCESS ROADEXISTING OIL LINE "B"
ABANDON IN PLACE
EXISTING OIL LINE "A"
ABANDON IN PLACE
DISCONNECT
AND CAP
BRANCH OFF
EXISTING
4-INCH DIA.
GAS LINE
APPROXIMATE
LOCATION OF
EXISTING SEPTIC
TANK AND LEACH
LINES FORMER GASOLINE
AST LOCATION
STORAGE
CONTAINER TO
BE REMOVED BY
CHEVRON
PLANTER
DEMOLISH
CONCRETE
FOOTINGS
DEMOLISH
CONCRETE
PAD
APPROXIMATE
LOCATION OF
EXISTING SEPTIC
TANK
EXISTING FENCE,
REMOVE FOR
CONSTRUCTION
RETAINING
WALL
WORK
CORRIDOR
ELECTRICAL
PANELS
ELECTRICAL PANEL
REMOVE MAIN GATE
AND BOLLARDS
ELECTRICAL AND SIGNS
OIL/WATER
SEPERATOR
EXISTING FENCE
REMOVE FOR
CONSTRUCTION VAULTS - DEMOLISH
AND REMOVE
CONCRETE PAD
CONCRETE PAD WITH
RAISED WALLS,
DEMOLISH AND REMOVE
EXISTING
PRODUCTION
WELL
(PROTECT-IN-PLACE)
FORMER SHED
CONCRETE PADFORMER ELECTRICAL
HOUSE FOUNDATION,
DEMOLISH AND REMOVE
CLEAR AREA FOR FUTURE
TANK FARM ROAD R-O-W
FIRE HYDRANT
DEMOLISH
EXISTING
BUILDING
DEMOLISH
EXISTING
BUILDING
LIMIT OF EXISTING
ASPHALT PARKING LOT
EXISTING LIGHT
STANDARDS - REMOVE
CONCRETE
FOUNDATION
DEMOLISH
EXISTING
BUILDING
DEMOLISH
EXISTING
BUILDING
EXISTING
OVERHEAD
POWER
LINES
2" GAS LINE
REPORTED TO BE
ABANDONED2" GAS LINE CUT AND
CAPPED BELOW GROUND
4" GAS LINE
(PROTECT-IN-PLACE)
FENCE
EXISTING EDGE
OF PAVEMENT
EXISTING
WATER TANK
4" WATER
LINE
2" GAS LINE
(REMOVE)
APPROXIMATE LOCATION
OF EXISTING LEACH LINES
APPROXIMATE
LOCATION OF
EXISTING WATER
LINE
APPROXIMATE
LOCATION OF
OVERHEAD
POWER LINE
APPROXIMATE LOCATION
OF EXISTING OVERHEAD
POWER LINE
SCALE
0 80 160 FEET
LEGEND
V:\1212_Padre-Chevron_SLOTF\1212.001_Remedial_Design\017_1212.001_NW_Operations_Area_Demo_Subgrade_Plan.dwg\05/12/14N
FIGURE 21
NORTHWEST OPERATIONS AREA
(OU #1/AOC #2)
DEMOLITION PLAN
REMEDIAL ACTION PLAN
SAN LUIS OBISPO TANK FARM
PREPARED FOR
CHEVRON EMC
SAN LUIS OBISPO, CALIFORNIA
SITE PROPERTY BOUNDARY
TOPOGRAPHIC CONTOUR
FENCEX
EXISTING BUILDING
125
TREE / BRUSH LINE
OPERABLE UNIT BOUNDARY
EXISTING LIGHT POLE
FIRE HYDRANT
EXISTING MONITORING / SUPPLY WELL
WETLAND - PROTECT-IN-PLACE
EXISTING BUILDING / STRUCTURE TO BE DEMOLISHED
NOTE:
DEMOLITION ASSUMES THAT SUBSURFACE PIPELINES
HAVE BEEN ADDRESSED.
POWER POLE
POWER LINEE
FORMER FIRE
SCHOOL LOCATION
EXISTING
TRENCH
FORMER BOILER AND
TANK LOCATIONS
FORMER PUMP STATION
LOCATION - REMOVED
(SEE NOTE?)
EXISTING MAIN
ACCESS GATE
TANK FARM ROADSTOPEXISTING
PRODUCTION
WELL
OU #1
BOUNDARY
B-33
B-35
B-36
MW-50
MW-56
MW-49
50'
INLET 2 BOX CULVERTS
ANTICIPATED
FUTURE TANK
FARM ROAD ROW
PROVIDE 4" DIA.
UNDERGROUND
ELECTRICAL
CONDUIT
SLOPE
SIDES
4:1
TOE OF SLOPE
ENERGY
DISSIPATER
RR-1
121
120121122122
123
INLETS
2-24" DIA. CMP
CULVERTS
11
CLEAR AND
GRADE TO
DRAIN
(2) 18" DIA. CMP
CULVERTS
EROSION
CONTROL
REPLACE FENCE
12
ENERGY
DISSIPATER
RR-2
END OF (2) 18" DIA.
CMP CULVERTS
FL ELEV. 121.00
BEGIN (2) 18" DIA.
CMP CULVERTS
FL ELEV. 121.50
REPLACE FENCE
SM-3
SM-2
SM-1
DITCH NW-6DITCH NW-7
DITCH NW-10
DITCH NW-9
DITCH NW-8
DITCH NW-1 DITCH NW-2
DITCH NW-3
DITCH NW-5
DITCH NW-4
DITCH
NW-14
DITCH
NW-11
DITCH NW-13
CATTLE
CROSSING
DITCH NW-12
ENERGY
DISSIPATOR RR-1A
ENERGY
DISSIPATOR RR-2A
B-57 120124
120
SLOPE
SIDES
4:1
SCALE
0 80 160 FEET
LEGEND
V:\1212_Padre-Chevron_SLOTF\1212.001_Remedial_Design\018_1212.001_NW_Operations_Area_Final_Grade_Plan.dwg\05/12/14N
FIGURE 22
NORTHWEST OPERATIONS AREA
(OU #1/AOC #2)
CAP GRADING PLAN
REMEDIAL ACTION PLAN
SAN LUIS OBISPO TANK FARM
PREPARED FOR
CHEVRON EMC
SAN LUIS OBISPO, CALIFORNIA
REFERENCE:
TOPOGRAPHIC MAP PROVIDED BY CENTRAL COAST
AERIAL MAPPING, DATED MARCH 2, 2007.
SITE PROPERTY BOUNDARY
TOPOGRAPHIC CONTOUR
FENCEX
EXISTING BUILDING
125
TREE / BRUSH LINE
OPERABLE UNIT BOUNDARY
EXISTING MONITORING / SUPPLY WELL
NEW RETAINING WALL
WETLAND - PROTECT-IN-PLACE
CROSS SECTION LOCATION
B
B'
D
C
A
A'C'
SURVEY MONUMENT
D'
ELEVATION (ft)ELEVATION (ft)STATION
115.00
120.00
125.00
130.00
135.00
115.00
120.00
125.00
130.00
135.00
-0+50.00 0+00.00 1+00.00 2+00.00 3+00.00 4+00.00 5+00.00 6+00.00 6+50.00
SEE FIGURE 25
TIE INTO
EXISTING GRADE
SEE FIGURE 26
TIE INTO
EXISTING
GRADE
TOP OF CAP
STRUCTURAL BACKFILL
COMPACTED TO 95% RELATIVE
MAXIMUM DENSITY
12 oz.
NON-WOVEN
GEOTEXTILE
UNDISTURBED EARTH
4' MIN
EXISTING GROUND
SURFACE
B B'V:\1212_Padre-Chevron_SLOTF\1212.001_Remedial_Design\043_1212.001_Northwest_Operations_Area_Sections.dwg\05/12/14FIGURE 24
NORTHWEST OPERATIONS AREA
(OU #1/AOC #2)
SECTION B-B'
REMEDIAL ACTION PLAN
SAN LUIS OBISPO TANK FARM
PREPARED FOR
CHEVRON EMC
SAN LUIS OBISPO, CALIFORNIA
HORIZONTAL SCALE
0 50 100 FEET
VERTICAL SCALE
0 10 20 FEET
ELEVATION (ft)ELEVATION (ft)STATION
110.00
115.00
120.00
125.00
130.00
110.00
115.00
120.00
125.00
130.00
0+00.00 0+25.00 0+50.00 0+65.00
℄
TANK FARM ROAD
EDGE OF EXISTING
PAVEMENT
⅊
REPLACE
EXISTING
FENCE
ASSUMED DEPTH OF EXISTING 4"
DIA. GAS LINE, PROTECT-IN-PLACE
EXISTING WATER
LINE
(DEPTH UNKNOWN)
FUTURE
HIGHWAY
ROW
4'
1'
DITCH FLOW LINE
ELEV. 120.3
4
1
12 oz.
NON-WOVEN
GEOTEXTILE
SUBGRADE
PREPARATION
LAYER
STRUCTURAL BACKFILL COMPACTED
TO 95% RELATIVE MAXIMUM DENSITY
UNDISTURBED
EARTH
CONSTRUCTION
CONTROL LINE
2'
DITCH AND SLOPES TO
BE ROUGHENED AND
REVEGETATED
1' MIN
3' MIN
SCALE
0 5 10 FEETV:\1212_Padre-Chevron_SLOTF\1212.001_Remedial_Design\019_1212.001_NW_Operations_Area_Sections.dwg\05/12/14FIGURE 25
NORTHWEST OPERATIONS AREA
(OU #1/AOC #2)
SECTION C-C'
REMEDIAL ACTION PLAN
SAN LUIS OBISPO TANK FARM
PREPARED FOR
CHEVRON EMC
SAN LUIS OBISPO, CALIFORNIA
EW-1
MW-32
MW-41
215 FT
FOUNDATION OF LIGHTENING TOWER NO. 13
PROTECTIVE ENCLOSURE
REMOVE (TYPICAL)
CUT AND CAP
HERE
ABANDON EXISTING
MONITORING WELLS
CONCRETE FOUNDATION
REMOVE AND DISPOSE
APPROXIMATE
LOCATION OF
LATERAL FROM
10" CRUDE OIL LINE
TO RESERVOIR 5
FORMER 10" DIA CRUDE-OIL
LINE ABANDONED-IN-PLACE
REMAINS OF PIPELINE
REMOVE AND DISPOSE REMOVE EXISTING
FENCE AND NETTING
BARBED WIRE FENCE
REMOVE AND DISPOSE
CONCRETE RUBBLE
REMOVE AND DISPOSE
DATA LOGGER
REMOVE
HYDROCARBON SEEPAGE
TEST STRUCTURE- ABANDON
CONSTRUCT ANCHOR
TRENCH FOR GEOTEXTILE
STEEL HOOP
REMOVE AND
DISPOSE
FOUNDATION OF
LIGHTNING TOWER NO. 11
REMOVE AND DISPOSE
FOUNDATION OF
LIGHTENING
TOWER NO. 12
REMOVE AND DISPOSE
BARBED WIRE FENCE
REMOVE AND DISPOSE
APPROXIMATE EXTENT
OF CONCRETE WALL
CONCRETE ON SLOPE
REMOVE AND DISPOSE
EXCAVATE IMPACTED SOILS
TO EXPOSE ORIGINAL
CONRETE BOTTOM
(±EL 119.50)
CLEAR AND GRUB LINE
DEFINES LIMITS OF WORK AREA
WATER LINE - REMOVE IF EXPOSED
OTHERWISE ABANDON IN-PLACE
DATA LOGGER
REMOVE
SCALE
0 80 160 FEET
LEGEND
V:\1212_Padre-Chevron_SLOTF\1212.001_Remedial_Design\015_1212.001_Reservoir_5_Existing_Conds_Demo_Plan.dwg\05/12/14N
FIGURE 28
RESERVOIR 5 (OU #2)
DEMOLITION PLAN
REMEDIAL ACTION PLAN
SAN LUIS OBISPO TANK FARM
PREPARED FOR
CHEVRON EMC
SAN LUIS OBISPO, CALIFORNIA
FENCEX
APPROXIMATE LOCATION OF 4" WATERLINE
LIMIT OF CLEAR AND GRUB
HYDROCARBON SURFACE EXPRESSION
REMEDIATION REQUIRED
HYDROCARBON SURFACE EXPRESSION -
REMEDIATION NOT REQUIRED
GROUNDWATER MONITORING WELL
FEATURE TO BE DEMOLISHED OR REMOVED
WETLAND - PROTECT-IN-PLACE
WETLAND - IMPACTED BY CONTRUCTION
MONITORING WELL
(PROTECT IN PLACE)
MW-37
STANDPIPE
REMOVE AND DISPOSE
EXPOSED PIPELINE
REMOVE AND DISPOSE
CONCRETE DOWN-DRAIN FOR
PERIMETER ROOF GUTTER
REMOVE AND DISPOSE
EXCAVATE IMPACTED SOILS
TO EXPOSE ORIGINAL
CONCRETE BOTTOM (± EL
116.50)
PIPELINE AND CONCRETE
TROUGH
REMOVE AND DISPOSE
CUT AND CAP LINE
AT THIS LOCATION
APPROXIMATE LOCATION OF
ABANDONED 12-INCH DIA.
CRUDE OIL LINE
SCALE
0 80 160 FEETV:\1212_Padre-Chevron_SLOTF\1212.001_Remedial_Design\016_1212.001_Reservoir_7_Existing_Conds_Demo_Plan.dwg\04/17/14N
FIGURE 29
RESERVOIR 7 (OU #2)
DEMOLITION PLAN
REMEDIAL ACTION PLAN
SAN LUIS OBISPO TANK FARM
PREPARED FOR
CHEVRON EMC
SAN LUIS OBISPO, CALIFORNIA
LEGEND
FENCEX
APPROXIMATE LOCATION OF 4" WATERLINE
LIMIT OF CLEAR AND GRUB
WETLAND - PROTECT-IN-PLACE
WETLAND - IMPACTED BY CONSTRUCTION
HYDROCARBON SURFACE EXPRESSION
REMEDIATION REQUIRED
HYDROCARBON SURFACE EXPRESSION -
REMEDIATION NOT REQUIRED
GROUNDWATER MONITORING WELL
FEATURE TO BE DEMOLISHED OR REMOVED
ABANDON
EXISTING
SEEPAGE
STRUCTURE
R5-E
REMOVE
EXISTING
FENCE
AND
NETTING
MW-32
MW-41
MW-32
EW-1121120119 124
125
126
127
128
129
130
1
1
8 125124123122126BORROW
DAYLIGHT
PERIMETER DITCH R5-2
(SEE NOTE 1)
PERIMETER DITCH R5-1
(SEE NOTE 1)
CONTOUR GRADE
FINISH SLOPE
(SEE NOTE 2)
ENERGY
DISSIPATOR
RR-4
ENERGY
DISSIPATOR
RR-3 MAX SLOPE9 %END
DITCH
R5-2
END
DITCH
R5-1
TOE OF
FILL
SLOPE
WETLANDS TO
BE RESTORED
(SEE NOTE 3)
SM-1
SM-2
SM-3
REFERENCE:
TOPOGRAPHIC CONTOURS PROVIDED BY EDA, INC., DATED JULY 11, 2007.
SCALE
0 80 160 FEET
LEGEND
V:\1212_Padre-Chevron_SLOTF\1212.001_Remedial_Design\029_1212.001_Reservoir_5_Cap_Grading_Plan.dwg\05/12/14N
FIGURE 30
RESERVOIR 5 (OU #2)
CAP GRADING PLAN
REMEDIAL ACTION PLAN
SAN LUIS OBISPO TANK FARM
PREPARED FOR
CHEVRON EMC
SAN LUIS OBISPO, CALIFORNIA
NOTES:
1. ESTABLISH DITCH FROM HIGHPOINT.
ESTABLISH GENTLE CURVE FOR WATER
COURSE USING CONTROL POINTS PROVIDED.
DITCH SLOPE SHALL NOT BE GREATER THAN
2%, NOR LESS THAN 0.5%.
2. CONTRACTOR SHALL CONTOUR GRADE
BETWEEN THE CONTROL CONTOUR AND THE
PERIMETER DITCH. GRADING SHALL MIMIC, TO
THE EXTENT POSSIBLE, NATURAL CONTOURS.
SLOPES SHALL BE NO STEEPER THAN 4:1, AND
NO FLATTER THAN 0.5%.
3. EXISTING WETLANDS DISTURBED WITHIN THE
CLEAR AND GRUB AREA AND OUTSIDE THE
FINAL GRADING AREA SHALL BE RESTORED AS
DESCRIBED IN THE RESTORATION PLAN.
TOPOGRAPHIC CONTOUR
FENCEX
125
TREE / BRUSH LINE
HYDROCARBON SURFACE EXPRESSION
REMEDIATION REQUIRED
HYDROCARBON SURFACE EXPRESSION
REMEDIATION NOT REQUIRED
CUT/FILL LINE
RIDGE
LIMIT OF CLEAR AND GRUB
WETLAND-PROTECT-IN-PLACE
WETLAND-IMPACTED BY CONSTRUCTION
SURVEY MONUMENT
MONITORING WELL
(PROTECT IN PLACE)
MW-37
TREE
PROTECT-IN-PLACE
APPROXIMATE LOCATION
ABANDONED
8-INCH DIA. CRUDE OIL LINE
APPROXIMATE
LOCATION ABANDONED
12-INCH DIA. CRUDE OIL
LINE
CLEAR AND
GRUB LINE
FILL
CUT
START OF DITCH
R7-1 & R7-2
HP FL ELEV. 130.24
PERIMETER
DITCH R7-1
(SEE NOTE 2)
PERIMETER
DITCH R7-2
(SEE NOTE 2)
ENERGY
DISSIPATOR
RR-6
CONTOUR GRADE
FINISH SLOPE
(SEE NOTE 3)
END OF
DITCH R7-1
TOE OF
FILL SLOPE
END OF
DITCH R7-2
WETLANDS TO
BE RESTORED
(SEE NOTE 4)
HP ELEV.
133.50
ENERGY
DISSIPATOR
RR-5
SM-1
SM-3
SM-2
REFERENCE:
TOPOGRAPHIC CONTOURS PROVIDED BY EDA, INC., DATED JULY 11, 2007.
SCALE
0 80 160 FEET
LEGEND
V:\1212_Padre-Chevron_SLOTF\1212.001_Remedial_Design\030_1212.001_Reservoir_7_Cap_Grading_Plan.dwg\05/12/14N
FIGURE 31
RESERVOIR 7 (OU #2)
CAP GRADING PLAN
REMEDIAL ACTION PLAN
SAN LUIS OBISPO TANK FARM
PREPARED FOR
CHEVRON EMC
SAN LUIS OBISPO, CALIFORNIA
TOPOGRAPHIC CONTOUR
FENCEX
125
TREE / BRUSH LINE
EXISTING MONITORING / SUPPLY WELL
HYDROCARBON SURFACE EXPRESSION
REMEDIATION REQUIRED
HYDROCARBON SURFACE EXPRESSION
REMEDIATION NOT REQUIRED
CUT/FILL LINE
RIDGE
LIMIT OF CLEAR AND GRUB
WETLAND-ROTECT-IN-PLACE
WETLAND-IMPACTED BY CONSTRUCTION
NOTES:
1. ALL WETLANDS OUTSIDE THE CLEAR AND GRUB LINE
SHALL BE PROTECTED IN PLACE.
2. ESTABLISH DITCH FROM HIGHPOINT. ESTABLISH
GENTLE CURVE FOR WATER COURSE USING CONTROL
POINTS PROVIDED. DITCH SLOPE SHALL NOT BE
GREATER THAN 2%, NOR LESS THAN 0.5%.
3. CONTRACTOR SHALL CONTOUR GRADE BETWEEN THE
CONTROL CONTOUR AND THE PERIMETER DITCH.
GRADING SHALL MIMICK, TO THE EXTENT POSSIBLE,
NATURAL CONTOURS. SLOPES SHALL BE NO STEEPER
THAN 4:1, AND NO FLATTER THAN 0.5%.
4. EXISTING WETLANDS WITHIN THE CLEAR AND GRUB
AREA AND OUTSIDE THE FINAL GRADING AREA SHALL
BE RESTORED AS DESCRIBED IN THE RESTORATION
PLAN.
SURVEY MONUMENT
ELEVATION (ft)ELEVATION (ft)STATION
85.00
95.00
105.00
115.00
125.00
135.00
145.00
155.00
165.00
85.00
95.00
105.00
115.00
125.00
135.00
145.00
155.00
165.00
-1+00.00 0+00.00 1+00.00 2+00.00 3+00.00 4+00.00 5+00.00 6+00.00 7+00.00 8+00.00 9+00.00
FINISH GRADEEXTENT OF
GRAVEL LAYER
APPROXIMATE EXTENT
OF CONCRETE FLOOR
APPROXIMATE LOCATION
OF ORIGINAL BERM
EXISTING BERM
USE AS BORROW FOR
STRUCTURAL FILL
TIE INTO
EXISTING GRADE
EXISTING GROUND
SURFACE
REMOVE EXISTING MATERIAL
AND DEBRIS TO EXPOSE
CONCRETE FLOOR
EXPOSE AND REMOVE
ANY REMAINING
CONCRETE ON SLOPE
4 (MAX)1
STRUCTURAL FILL COMPACT
TO AT LEAST 90% RELATIVE
MAXIMUM DENSITY (ASTM D1557)
GOETEXTILE
ANCHOR TRENCH
12 oz. NON-WOVEN
GEOTEXTILE
1-FOOT THICK (MIN.)
GROWTH MEDIUM
(SEE NOTE 5)
DETAIL 1 ON FIGURE 33
DETAIL 2 ON FIGURE 33
0 80 160 FEET
0 40 80 FEETV:\1212_Padre-Chevron_SLOTF\1212.001_Remedial_Design\020_1212.001_Reservoir_5_Section_G.dwg\05/12/14FIGURE 32
RESERVOIRS 5 AND 7 (OU #2)
TYPICAL SECTION
REMEDIAL ACTION PLAN
SAN LUIS OBISPO TANK FARM
PREPARED FOR
CHEVRON EMC
SAN LUIS OBISPO, CALIFORNIA
HORIZONTAL SCALE
VERTICLE SCALE
3'
1'
12 oz. GEOTEXTILE LINER
GRAVEL
CONCRETE ON SLOPE
(REMOVED)
SHELF FOR
ANCHOR TRENCH
EXISTING GRADE
BACKFILL TO ANCHOR GEOTEXTILE AND
COMPACT TO 90% RELATIVE MAXIMUM DENSITY
(PER ASTM D1557)
3'
VARIES
2' (MIN.)
1' (MIN.)
GROWTH MEDIUM
STRUCTURAL FILL
GEOTEXTILE
GRAVEL
EXISTING CONCRETE
RESERVOIR BOTTOM
EXISTING SUBGRADE
1.5' (MIN.)
TOP OF GRAVEL ELEV.
RESERVOIR 5: 119.20
RESERVOIR 7: 123.50
HIGH GROUNDWATER ELEV.
RESERVOIR 5: 117.70
RESERVOIR 7: 122.00
TOP OF CONC. ELEV.
RESERVOIR 5: 116.00
RESERVOIR 7: 116.50
0 8 16 FEET
SCALEV:\1212_Padre-Chevron_SLOTF\1212.001_Remedial_Design\020_1212.001_Reservoir_5_Section_G.dwg\04/17/14FIGURE 33
RESERVOIRS 5 AND 7 (OU #2)
TYPICAL CAP DETAILS
REMEDIAL ACTION PLAN
SAN LUIS OBISPO TANK FARM
PREPARED FOR
CHEVRON EMC
SAN LUIS OBISPO, CALIFORNIA
0 5 10 FEET
SCALE
DETAIL 2
DETAIL 1
RESERVOIR 4
RESERVOIR
2
FORMER
RECYCLING
AREA
T A N K F A R M R O A D
BORROW No. 2GROSS AREA 8.54 ACTOPSOIL 20,700 CY
FLOWER MOUND/OU #3GROSS AREA 55.1 ACCOMMON EARTH 317,162 CY
OFF-SITE GRADINGGROSS AREA 4.1 ACCOMMON EARTH 73,660 CY
S:\GIS\1212_Chevron_Padre_SLOTF\001_Remedial_Design\ArcMapDocuments\022_1212.001_Res_4-OU3_Flower_Mound_Borrow_2_Work_Areas.mxd\12/18/07FIGURE 34
RESERVOIR 4 (OU #3),
FLOWER MOUND, AND BORROW No. 2
WORK AREAS
REMEDIAL ACTION PLANSAN LUIS OBISPO TANK FARM
PREPARED FORCHEVRON EMCSAN LUIS OBISPO, CALIFORNIA
REFERENCE:AERIAL PHOTOGRAPH BY CENTRAL COAST AERIAL MAPPING.DATED MARCH 2, 2007.
EXPLANATION
PROJECT AREA BOUNDARY
WORK AREAS
APPROXIMATE
SCALE
FEET
0 250 500125
TANK FARM ROAD
EXISTING FENCE
PROTECT-IN-PLACE NEW FENCE
EXISTING FENCE
REMOVE AND DISPOSE
EXISTING FENCE
PROTECT-IN-PLACE
ASPHALTIC MATERIAL
EXISTING WETLAND 0.068 Ac REMOVE
ASPHALTIC MATERIAL
ASPHALTIC MATERIAL
ASPHALTIC LOCATION OF
ROOF FOUNDATION
ASPHALTIC MATERIAL
EXISTING WETLAND 0.044 Ac REMOVE
EXISTING UTILITY POLES
PROTECT-IN-PLACE
FORMER PUMP-HOUSE CONCRETE FOUNDATIONS
REMOVE AND DISPOSE
FORMER 10-INCH CRUDE-OIL LINE
REMOVE AND DISPOSE
NEW FENCE
ABANDON FENCE
CUT AND CAP WATERLINE
EXISTING WETLAND 0.023 Ac REMOVE
APPROXIMATE LOCATION OF FORMER
CONCRETE FOUNDATION OF FORMER
RESERVOIR WALL
FORMER CRUDE-OIL PIPELINE
CONCRETE FOUNDATION
LIGHTNING TOWER No. 2
REMOVE AND DISPOSE
4" DIA. FIRE WATER
DISTRIBUTION LINE
CLEAR AND GRUB LINE
EXISTING BARBED-WIRE FENCE
REMOVE AND DISPOSE
REMOVE AND DISPOSE
BARBED-WIRE FENCE
REMOVE AND DISPOSE
EXISTING WETLAND 0.022 Ac REMOVEREMOVE AND DISPOSE
EXISTING WETLAND 0.053 Ac REMOVE
BARBED-WIRE FENCE
REMOVE AND DISPOSE
EXISTING WETLAND 0.316 Ac
REMOVE TO CLEAR AND GRUB LINE
WOOD FRAME TEST PLOT
REMOVE AND DISPOSE
WOOD FRAME TEST PLOT
REMOVE AND DISPOSE
REMOVE AND DISPOSE
WOOD FRAME TEST PLOTS
REMOVE AND DISPOSE
CONCRETE FOUNDATION
LIGHTENING TOWER No. 1
REMOVE AND DISPOSE
EXISTING WETLAND .0125 Ac REMOVE
EXISTING WETLAND
PROTECT-IN-PLACE
BARBED-WIRE FENCE
REMOVE AND DISPOSE
MONITORING WELL TMW-9 ABANDON
EXISTING PROPANE
CANON TO BE
REMOVED BY
CHEVRON
REMOVE AND DISPOSE
APPROXIMATE LOCATION
OF EXPOSED WATER LINE
REMOVE AND DISPOSE
APPROXIMATE LOCATION
OF FORMER TANK
GAUGING CABLE
CUT AND CAP
CRUDE-OIL LINE
EXISTING WETLAND .007 Ac REMOVE
REFERENCE:
TOPOGRAPHIC CONTOURS PROVIDED BY EDA, INC., DATED JULY 11, 2007.
SCALE
0 120 240 FEET
LEGEND
V:\1212_Padre-Chevron_SLOTF\1212.001_Remedial_Design\031_1212.001_Reservoir_4_Demolition_Plan.dwg\05/13/14N
FIGURE 35
RESERVOIR 4 (OU #3)
DEMOLITION PLAN
REMEDIAL ACTION PLAN
SAN LUIS OBISPO TANK FARM
PREPARED FOR
CHEVRON EMC
SAN LUIS OBISPO, CALIFORNIA
TOPOGRAPHIC CONTOUR
FENCEX
125
TREE / BRUSH LINE
EXISTING MONITORING / SUPPLY WELL
CUT/FILL LINE
RIDGE
LIMIT OF CLEAR AND GRUB
WETLAND-PROTECT-IN-PLACE
HYDROCARBON SURFACE EXPRESSION
REMEDIATION REQUIRED
HYDROCARBON SURFACE EXPRESSION -
REMEDIATION NOT REQUIRED
WETLAND-IMPACTED BY CONSTRUCTION
REMOVE FENCE
REMOVE FENCE EAST OF
THIS POINT (SEE NOTE 5)
REMOVE FENCE SOUTH OF
THIS POINT (SEE NOTE 5)
CLEAR AND GRUB
(SEE NOTE 1)
RELOCATE EXISTING OVERHEAD POWER AND
TELECOMMUNICATION LINES TO AN AREA
OUTSIDE GRADING FOOTPRINT (SEE NOTE 4)
REMOVE FENCE NORTH OF
THIS POINT (SEE NOTE 5)
WETLANDS TO BE REMOVED
(SEE NOTE 3)
REMOVE FENCE WEST OF
THIS POINT (SEE NOTE 5)
N
FIGURE 36
FLOWER MOUND DEMOLITION PLAN
REMEDIAL ACTION PLAN
SAN LUIS OBISPO, CALIFORNIA
PREPARED FOR
CHEVRON EMC
SAN LUIS OBISPO, CALIFORNIAV:\1212_Padre-Chevron_SLOTF\1212.001_Remedial_Design\046_1212.001_Flowermound_Demolition_Plan.dwg\05/12/14SCALE
0 150 300 FEET
NOTES:
1. CLEAR AND GRUB WITH THIS BOUNDARY. AREA WITHIN
THIS BOUNDARY IS CONSIDERED THE WORK AREA FOR
THIS PORTION OF THE PROJECT. CLEARING SHALL
INCLUDE, IN ADDITION TO VEGETATION AND UNLESS
OTHERWISE NOTED, REMOVAL AND DISPOSAL OF ALL
CONCRETE DEBRIS, STRUCTURES, FEATURES,
MONITORING WELLS, AND HYDROCARBON IMPACTED
SOIL.
2. MONITORING WELLS WITHIN THE WORK AREA SHALL BE
ABANDONED IN ACCORDANCE WITH THE REQUIREMENTS
OF SAN LUIS OBISPO COUNTY DEPARTMENT OF
ENVIRONMENTAL HEALTH AND WITH CALIFORNIA
DEPARTMENT OF WATER RESOURCES BULLETIN NO. 74-81.
3. WETLANDS WITHIN THE CLEAR AND GRUB BOUNDARY
SHALL BE PERMANENTLY REMOVED. WETLANDS OUTSIDE
THE CLEAR AND GRUB LINE SHALL BE
PROTECTED-IN-PLACE. THOSE WETLANDS ADJACENT TO
THE WORK AREA SHALL BE PROTECTED AS DESCRIBED IN
THE SPECIAL PROVISIONS.
4. THE EXISTING POWER POLES CARRY ACTIVE POWER LINES
BELONGING TO PG&E, AND TELECOMMUNICATION LINES
BELONGING TO AT&T OR CHARTER CABLE. CONTRACTOR
SHALL TEMPORARILY RELOCATE LINES OUTSIDE THE
WORK AREA DURING GRADING ACTIVITIES. THE
CONTRACTOR SHALL COORDINATE WITH PG&E AND AT&T
IF RELOCATION IS NECESSARY.
5. FENCE WITHIN THE CLEAR AND GRUB LINE SHALL BE
REMOVED. FENCE OUTSIDE THE WORK AREA SHALL BE
PROTECTED-IN-PLACE. GAPS IN THE FENCE ALLOWING
ACCESS TO THE PROPERTY FROM OFF-SITE SHALL BE
CLOSED BY NEW FENCE OUTSIDE THE WORK AREA.
REFERENCE:
TOPOGRAPHIC CONTOURS AND FEATURES
PROVIDED BY EDA, INC., DATED JULY 11, 2007.
X
LEGEND
125
HYDROCARBON SURFACE EXPRESSION -
REMEDIATION REQUIRED
HYDROCARBON SURFACE EXPRESSION -
REMEDIATION NOT REQUIRED
EXISTING MONITORING /
SUPPLY WELL
FIRE HYDRANT
LIMITS OF CLEAR AND GRUB
FENCE
TREE / BRUSH LINE
TOPOGRAPHIC CONTOUR
WETLAND - PROTECT-IN-PLACE
WETLAND - IMPACTED BY CONSTRUCTION
TANK FARM ROAD
EXTENT OF
SURFACE
EXPRESSION
EXCAVATION
ASPHALTIC MATERIAL
EXISTING PG&E OVERHEAD ELECTRICAL
PROTECT-IN-PLACE
APPROXIMATE LOCATION OF
FORMER CONCRETE FOUNDATION
OF FORMER RESERVOIR WALL APPROXIMATE EXTENT
OF GEOTEXTILE
ASPHALTIC MATERIAL
TMW-9
(TO BE ABANDONED)
REFERENCE:
TOPOGRAPHIC CONTOURS PROVIDED BY EDA, INC., DATED JULY 11, 2007.
SCALE
0 120 240 FEET
V:\1212_Padre-Chevron_SLOTF\1212.001_Remedial_Design\032_1212.001_Reservoir_4_Excavation_and_Geotextile_Placement_Plan.dwg\05/12/14N
FIGURE 37
RESERVOIR 4 (OU #3)
EXCAVATION AND GEOTEXTILE
PLACEMENT PLAN
REMEDIAL ACTION PLAN
SAN LUIS OBISPO TANK FARM
PREPARED FOR
CHEVRON EMC
SAN LUIS OBISPO, CALIFORNIA
LEGEND
TOPOGRAPHIC CONTOUR
FENCEX
125
TREE / BRUSH LINE
EXISTING MONITORING / SUPPLY WELL
APPROXIMATE EXTENT OF GEOTEXTILE
LIMIT OF CLEAR AND GRUB
HYDROCARBON SURFACE EXPRESSION
REMEDIATION REQUIRED
HYDROCARBON SURFACE EXPRESSION -
REMEDIATION NOT REQUIRED
WETLAND - PROTECT-IN-PLACE
WETLAND - IMPACTED BY CONSTRUCTION
TANK FARM ROAD
LIMIT OF
GRADING
LIMIT OF
GRADING
SANTA
F
E
RO
A
D
TANK FARM ROAD
REPLACE FENCE
16015515014514013513013013514016016
0 1651701551
5
0145
140 150
1
5
5
PROVIDE
STORMWATER
RETENTION BASIN
COLLECTOR LOOPCUTFILLCUT
FILL
CUT
FILL
CUTFILL
CUTFILLCUTFILLFIL
L
CU
T
CUT
FILL
CUTFILLCUT
FILL FILLCUTFILLCUT
DITCH ED-2
DITCH ED-4
DITCH ED-8
DITCH ED-7
DITCH ED-6
DITCH ED-1
DITCH ED-5
DITCH ED-10
DITCH ED-11
DITCH ED-12
DITCH ED-9
DITCH ED-3
TIE SANTA FE ROAD
INTO EXISTING
GROUND ELEV. 160.00
ENERGY DISSIPATOR
RR-7
ENERGY DISSIPATOR
RR-9
ENERGY DISSIPATOR
RR-8V:\1212_Padre-Chevron_SLOTF\1212.001_Remedial_Design\041_1212.001_Reservoir_4_Cap_Grading_Plan.dwg\05/12/14SCALE
0 200 400 FEET
FIGURE 38
RESERVOIR 4 (OU #3)
CAP GRADING PLAN
REMEDIAL ACTION PLAN
SAN LUIS OBISPO TANK FARM
PREPARED FOR
CHEVRON EMC
SAN LUIS OBISPO, CALIFORNIA
CUT/FILL LINE
LIMIT OF CLEAR AND GRUB
HYDROCARBON SURFACE EXPRESSION
REMEDIATION REQUIRED
HYDROCARBON SURFACE EXPRESSION -
REMEDIATION NOT REQUIRED
TOPOGRAPHIC CONTOUR
FENCEX
125
TREE / BRUSH LINE
N
LEGEND
REFERENCE:
TOPOGRAPHIC CONTOURS PROVIDED BY EDA, INC., DATED JULY 11, 2007.
J
J'
WETLAND - PROTECT-IN-PLACE
WETLAND - IMPACTED BY CONSTRUCTION
EXTENT OF PROPOSED TANK
FARM ROAD EXPANSION
EXTENT OF EXISTING
TANK FARM ROAD
TANK FARM ROAD
HP 147.40
HP 148.50
1
4
9
1
4
8
1
4
6
1
4
5
1
4
3
1
4
2
1
4
0 145144143151
152
1501
4
7
1
5
0145
140 150FIL
L
CU
T
CUT
FILLCUTFILL CUT
FILL
FILLCUT FILLCUTFILLCUTDITCH ED-6
DITCH BA-1
DITCH BA-2
DITCH BA-5
DITCH BA-3
DITCH BA-4
DITCH BA-8
DITCH BA-6
DITCH BA-7
ENERGY
DISSIPATOR RR-10
ENERGY
DISSIPATOR RR-12
ENERGY
DISSIPATOR RR-11
MW-17
(PROTECT IN PLACE OR
ABANDON AND REPLACE)
MW-18
(PROTECT IN PLACE OR
ABANDON AND REPLACE)
N
V:\1212_Padre-Chevron_SLOTF\1212.001_Remedial_Design\045_1212.001_BA2_Grading_Plan.dwg\05/12/14FIGURE 39
BORROW AREA NO. 2 GRADING PLAN
REMEDIAL ACTION PLAN
SAN LUIS OBISPO, CALIFORNIA
PREPARED FOR
CHEVRON EMC
SAN LUIS OBISPO, CALIFORNIA
SCALE
0 150 300 FEET
X
LEGEND
125
HYDROCARBON SURFACE EXPRESSION -
REMEDIATION REQUIRED
HYDROCARBON SURFACE EXPRESSION -
REMEDIATION NOT REQUIRED
EXISTING MONITORING /
SUPPLY WELL
FENCE
TREE / BRUSH LINE
TOPOGRAPHIC CONTOUR
WETLAND - PROTECT-IN-PLACE
WETLAND - IMPACTED BY CONSTRUCTION
SITE PROPERTY BOUNDARY
CUT/FILL LINE
10"
16"
B-36
B-35
B-33
(ABANDON)
PG&E ELECTRICAL POWER
POLE AND OVERHEAD
ELECTRICAL LINES,
PROTECT-IN-PLACE
(SEE NOTE 4)
MISC. CONCRETE
FOUNDATIONS,
REMOVE AND DISPOSE
BOTTOM OF
EXCAVATION
(SEE NOTE 5)
ABANDON EXISTING
MONITORING WELL
(SEE NOTE 4)
LIMIT OF CLEAR
AND GRUB
(SEE NOTE 1)
PROTECTIVE ENCLOSURE
REMOVE AND DISPOSE
(SEE NOTE 2)
EXISTING FENCE
PROTECT-IN-PLACE
3
2
1
PROTECTIVE ENCLOSURE
REMOVE AND DISPOSE
(SEE NOTE 2)
PROTECTIVE ENCLOSURE
REMOVE AND DISPOSE
(SEE NOTE 2)
SLOPE
SIDES
2:1
LIMIT OF
EXCAVATION
(SEE NOTE 5)
(ABANDON)
VEGETATION AND
CLEAN SOIL
STOCKPILE AREA
(SEE NOTE 6)
TANK FARM ROAD
EXISTING TRASH/RUBBLE PILE,
REMOVE AND DISPOSE
EXISTING WATER LINE
ABANDON-IN-PLACE
CRUDE OIL LINE
ABANDON-IN-PLACE EXISTING GAS LINE
ABANDON-IN-PLACE
EXISTING WATER LINE
REMOVE AND DISPOSE
EXISTING CRUDE OIL LINES
REMOVE AND DISPOSE
EXISTING WATER AND
FOAMITE LINES,
REMOVE AND DISPOSE
(ABANDON)
NOTES:
1. CLEAR AND GRUB WITHIN THIS BOUNDARY. CLEARING
SHALL INCLUDE REMOVAL AND DISPOSAL OF ALL
CONCRETE DEBRIS, STRUCTURES, FEATURES,
MONITORING WELLS AND HYDROCARBON IMPACTED
SOIL NOT NOTED IN THESE DRAWINGS. VEGETATION
REMOVED AS PART OF CLEARING AND GRUBBING
ACTIVITIES SHALL BE SAVED AND STOCKPILED IN
ACCORDANCE WITH THE WETLAND MITIGATION PLAN.
2.PROTECTIVE ENCLOSURES SHALL BE DISMANTLED
AND PROPERLY DISPOSED. IMPACTED SOIL BENEATH
ANY ENCLOSURE SHALL BE REMOVED AS DESCRIBED
IN THE SPECIFICATIONS.
3. THE CONTRACTOR SHALL TAKE ALL NECESSARY
PRECAUTIONS TO ENSURE THE EXISTING PG&E
ELECTRICAL POWER POLES AND OVERHEAD
ELECTRICAL LINES IN AND AROUND THE EXCAVATION
AREA ARE NOT DAMAGED OR DESTROYED.
4.MONITORING WELLS WITHIN THE WORK AREA SHALL BE
ABANDONED IN ACCORDANCE WITH CALIFORNIA
DEPARTMENT OF WATER RESOURCES BULLETIN No.
74-81.
5.EXCAVATION OF THE NORTH MARSH AREA SHALL BE
TO A MINIMUM DEPTH OF 3-FEET 6-INCHES AND TO A
MINIMUM EXTENT AS SHOWN ON THESE DRAWINGS. A
CALIFORNIA REGISTERED GEOLOGIST OR CIVIL
ENGINEER SHALL BE PRESENT AT ALL TIMES DURING
EXCAVATION. EXCAVATION SIDES SHALL BE SLOPED
AT A MAXIMUM OF 2:1. THE EXCAVATION LIMITS
SHOWN ON THESE DRAWINGS IS A MINIMUM
EXCAVATION LIMIT AND MAY INCREASE IF
CONTAMINATION IS FOUND TO EXIST BEYOND THE
LIMITS INDICATED.
6. VEGETATION AND CLEAN SOIL GENERATED BY THE
EXCAVATION SHALL BE STOCKPILED IN THIS AREA TO
BE USED AS CLEAN BACKFILL AND TO RE-VEGETATE
AFTER BACKFILL.
7.UTILITY LOCATIONS ARE APPROXIMATE. ACTUAL
LOCATIONS TO BE VERIFIED IN THE FIELD.
8.PORTIONS OF CRUDE OIL AND WATER LINES
EXTENDING ALONG THE NORTH SIDE OF TANK FARM
ROAD WERE REMOVED AS PART OF THE CITY'S SEWER
PROJECT IN 2008.
REFERENCE:
TOPOGRAPHIC CONTOURS PROVIDED BY EDA, INC., DATED JULY 11, 2007.
SCALE
0 120 240 FEET
V:\1212_Padre-Chevron_SLOTF\1212.001_Remedial_Design\034_1212.001_North_Marsh_Demolition_and_Excavation_Plan.dwg\05/12/14N
FIGURE 41
NORTH MARSH (OU #3/AOC #1)
DEMOLITION AND EXCAVATION PLAN
REMEDIAL ACTION PLAN
SAN LUIS OBISPO TANK FARM
PREPARED FOR
CHEVRON EMC
SAN LUIS OBISPO, CALIFORNIA
LEGEND
TOPOGRAPHIC CONTOUR
FENCEX
125
TREE / BRUSH LINE
EXISTING MONITORING / SUPPLY WELL
CUT/FILL LINE
LIMIT OF CLEAR AND GRUB
HYDROCARBON SURFACE EXPRESSION
REMEDIATION REQUIRED
HYDROCARBON SURFACE EXPRESSION -
REMEDIATION NOT REQUIRED
RIDGE
WETLAND - PROTECT-IN-PLACE
WETLAND - IMPACTED BY CONSTRUCTION
10" OIL LINE
ABANDON IN PLACE
TREE
PROTECT-IN-PLACE
HYDROCARBON
SURFACE EXPRESSION
EXCAVATION LIMIT
300'
VEGETATION AND
CLEAN SOIL
STOCKPILE AREA
HYDROCARBON
SURFACE EXPRESSION
EXCAVATION LIMIT
WETLANDS TO
BE RESTORED
LIMIT OF CLEAR
AND GRUB
4" DIA.
WATER LINE
LIMIT OF
RESERVOIR 3
EXCAVATION
REFERENCE:
TOPOGRAPHIC CONTOURS PROVIDED BY EDA, INC., DATED JULY 11, 2007.
SCALE
0 120 240 FEETV:\1212_Padre-Chevron_SLOTF\1212.001_Remedial_Design\035_1212.001_Reservoir_3_Demolition_and_Excavation_Plan.dwg\05/12/14N
FIGURE 42
RESERVOIR 3 (OU #3/AOC #2)
DEMOLITION AND EXCAVATION PLAN
REMEDIAL ACTION PLAN
SAN LUIS OBISPO TANK FARM
PREPARED FOR
CHEVRON EMC
SAN LUIS OBISPO, CALIFORNIA
LEGEND
TOPOGRAPHIC CONTOUR
FENCEX
125
TREE / BRUSH LINE
CUT/FILL LINE
LIMIT OF CLEAR AND GRUB
HYDROCARBON SURFACE EXPRESSION
REMEDIATION REQUIRED
HYDROCARBON SURFACE EXPRESSION -
REMEDIATION NOT REQUIRED
RIDGE
WETLAND - PROTECT-IN-PLACE
WETLAND - IMPACTED BY CONSTRUCTION
MW-35ACCESS ROAD
CENTER
OF
EXCAVATION
LIMIT OF CLEAR
AND GRUB
10" OIL LINE
ABANDON IN PLACE
TREE
PROTECT-IN-PLACE
300'
4" DIA.
WATER
LINE
135
134
WETLANDS
TO BE
RESTORED
GRADE TO A
MAXIMUM
ELEVATION OF
134.00 FT.
LIMIT OF
RESERVOIR 3
EXCAVATION
AND ANCHOR
TRENCH
WETLANDS
TO BE
RESTORED
N 2285072.87
E 5768516.42 SM-2
SM-3
V:\1212_Padre-Chevron_SLOTF\1212.001_Remedial_Design\037_1212.001_Reservoir 3_Final Grading Plan.dwg\05/12/14SCALE
0 120 240 FEET
N
LEGEND
TOPOGRAPHIC CONTOUR
FENCEX
125
TREE / BRUSH LINE
EXISTING MONITORING / SUPPLY WELL
LIMIT OF CLEAR AND GRUB
HYDROCARBON SURFACE EXPRESSION
REMEDIATION REQUIRED
HYDROCARBON SURFACE EXPRESSION -
REMEDIATION NOT REQUIRED
FIGURE 43
RESERVOIR 3 (OU #3/AOC #2)
GRADING PLAN
REMEDIAL ACTION PLAN
SAN LUIS OBISPO TANK FARM
PREPARED FOR
CHEVRON EMC
SAN LUIS OBISPO, CALIFORNIA
SURVEY MONUMENT
WETLAND - PROTECT-IN-PLACE
WETLAND - IMPACTED BY CONSTRUCTION
LIMIT OF CLEAR
AND GRUB
HYDROCARBON SURFACE
EXPRESSION EXCAVATION LIMIT
4" DIA.
WATER LINE
EXISTING FENCE
AND NETTING
REMOVE AND DISPOSE
REMOVE AND DISPOSE
LIMIT OF CLEAR AND GRUB
EXISTING
RESERVOIR 2
CONCRETE WALL
EXISTING PEBBLE
STRUCTURE
REMOVE AND DISPOSE
FORMER 2" DIA. GAS LINE
ABANDON-IN-PLACE
FORMER 10"
CRUDE-OIL LINE
ABANDON-IN-PLACE
FOUNDATION
OF LIGHTNING
TOWER No. 15
RESERVOIR
2
HYDROCARBON SURFACE
EXPRESSION EXCAVATION LIMIT
CUT AND CAP 10"
CRUDE-OIL LINE
HERE
FORMER 10" DIA.
CRUDE-OIL LINE
ABANDONED-IN-PLACE
FORMER 10" DIA.
CRUDE-OIL LINE
REMOVE AND DISPOSE
LIMIT OF CLEAR
AND GRUB
FORMER 8" DIA.
CRUDE-OIL LINE
ABANDONED-IN-PLACE
4" DIA. WATER LINE
FORMER 12" DIA.
CRUDE-OIL LINE
ABANDONED-IN-PLACE
EXISTING VALVE VAULT
REMOVE AND DISPOSE
CUT AND CAP
12" CRUDE-OIL
LINE HERE
FORMER 12" DIA.
CRUDE-OIL LINE
REMOVE AND DISPOSE
HYDROCARBON
SURFACE EXPRESSION
EXCAVATION LIMIT
HYDROCARBON
SURFACE EXPRESSION
EXCAVATION LIMIT
REFERENCE:
TOPOGRAPHIC CONTOURS PROVIDED BY EDA, INC., DATED JULY 11, 2007.
SCALE
0 120 240 FEETV:\1212_Padre-Chevron_SLOTF\1212.001_Remedial_Design\036_1212.001_Other_PPSH_Areas.dwg\05/12/14N
FIGURE 45
OTHER PPSH-IMPACTED AREAS
REMEDIAL ACTION PLAN
SAN LUIS OBISPO TANK FARM
PREPARED FOR
CHEVRON EMC
SAN LUIS OBISPO, CALIFORNIA
SCALE
0 60 120 FEETPLAN
SOUTH OF RESERVOIR 5
SCALE
0 100 200 FEETPLAN
WEST OF RESERVOIR 2
SCALE
0 100 200 FEETPLAN
RESERVOIR 2
LEGEND
TOPOGRAPHIC CONTOUR
FENCEX
125
TREE / BRUSH LINE
CUT/FILL LINE
LIMIT OF CLEAR AND GRUB
WETLAND - PROTECT-IN-PLACE
HYDROCARBON SURFACE EXPRESSION
REMEDIATION REQUIRED
HYDROCARBON SURFACE EXPRESSION -
REMEDIATION NOT REQUIRED
PPSH = PLIABLE PLASTIC SURFACE HYDROCARBON
WETLAND - IMPACTED BY CONSTRUCTION
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RESERVOIR 4
NORTHWEST
AREA
RESERVOIR
5
RESERVOIR
6
RESERVOIR
7
RESERVOIR
3
RESERVOIR
2
FORMER
RECYCLING
AREA
S:\GIS\1306_SLOTF-EMC_Work_Activities\1306.003_2013_Work_Activities\ArcMapDocuments022_1306.003_Areas_of_Habitat_Impact.mxd\11/21/13FIGURE 46
AREAS OF HABITAT IMPACT
REMEDIAL ACTION PLAN
SAN LUIS OBISPO TANK FARM
PREPARED FOR
CHEVRON EMC
SAN LUIS OBISPO, CALIFORNIA
0 500 1,000250
Feet
Approximate
Scale
NOTE:
CRLF = CALIFORNIA RED LEGGED FROG
SOURCE: BIOLOGICAL RESOURCES MAPPING CONDUCTED BY
RINCON CONSULTANTS INC., 2003. FIELD STUDIES PERFORMED
MAY THROUGH SEPTEMBER 2003.
REFERENCE: AERIAL PHOTOGRAPH BY CENTRAL COAST AERIAL MAPPING.
DATED: FEBRUARY 4, 2008
EXPLANATION
SITE PROPERTY BOUNDARY
ıôó SOUTHERN CALIFORNIA WALNUT
HOOVER'S BUTTON CELERY
PURPLE NEEDLEGRASS GRASSLAND
SLO (CAMBRIA) MORNING GLORY
SLO MORNING GLORY (2003 SURVEY)
SLO OWL'S CLOVER
SLO SERPENTINE DUDLEYA
CONGDON'S TARPLANT
DELINEATED WETLAND
PROTECTED FAIRY SHRIMP
PRESENT (32.56 ACRES)
PROTECTED FAIRY SHRIMP
NOT PRESENT (71.80 ACRES)
HABITAT IMPACT
!! !! !
Total Project Disturbance Area
STAGING AREA
BORROW AREAS
ACCESS ROUTE!! !! !
ID Task Name1Agency Permitting2Revision of Airport Area Specific Plan and General Plan3Approval of AASP and General Plan Revisions4RWQCB Review of RAP5RWQCB RAP Approval6Project Approval7Project Permitting8Remediation and Grading9Completion of Remediation (Sumittal of Closure Report)6/306/306/305/31Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q2Q3Q4Q1Q200720082009201020112012201320142015201620172018220092014TaskMilestoneFigure 47Preliminary ScheduleRemedial Action PLanChevron San Luis Obispo Tank Farm