LTLW Working Parties Amended Groundwater Investigation Work Plan 3-19-2018 (2)
EKI Environment & Water, Inc.
577 Airport Blvd, Suite 500
Burlingame, California 94010
(650) 292-9100
AMENDED
GROUNDWATER INVESTIGATION WORK PLAN
Former Lake Tahoe Laundry Works Site
1024 Lake Tahoe Boulevard,
South Lake Tahoe, California
(EKI A70020.03)
19 March 2018
577 Airport Blvd. Suite 500 Burlingame, CA 94010 (650) 292-9100 ekiconsult.com
formerly known as Erler & Kalinowski, Inc. Oakland, CA (510) 452-5700 ● Larkspur, CA (415) 464-9245 ● Los Angeles, CA (310) 857-1600 ● Centennial, CO (303) 796-0556
19 March 2018
Mr. Brian Grey, PG
Engineering Geologist
California Regional Water Quality Control Board, Lahontan Region
2501 Lake Tahoe Boulevard
South Lake Tahoe, California 96150
Subject: Amended Groundwater Investigation Work Plan
Former Lake Tahoe Laundry Works Site
1024 Lake Tahoe Boulevard, South Lake Tahoe, California
(EKI A70020.03)
Dear Mr. Grey:
Attached is EKI Environment & Water, Inc.’s (formerly Erler & Kalinowski, Inc.) (“EKI’s”) Amended
Groundwater Investigation Work Plan (“Work Plan”) for the former Lake Tahoe Laundry Works (“LTLW”)
site located at 1024 Lake Tahoe Boulevard in South Lake Tahoe, California (“Site”). EKI is submitting this
amended Work Plan on behalf of Seven Springs Limited Partnership (“Seven Springs”) and Fox Capital
Management Corporation (“Fox”) (collectively the “Working Parties”) as requested by the California
Regional Water Quality Control Board, Lahontan Region (“Water Board”) in its letter, dated
1 February 2018.
Please let us know if you have any questions or need further assistance.
Very truly yours,
EKI Environment & Water, Inc.
Paul B. Hoffey
Project Manager
Andrew N. Safford, PE
Project Engineer
AMENDED
GROUNDWATER INVESTIGATION WORK PLAN
Former Lake Tahoe Laundry Works Site
1024 Lake Tahoe Boulevard, South Lake Tahoe, California
CONTENTS
EKI A70020.03 i 19 March 2018
1. INTRODUCTION ................................................................................................................................... 1-1
2. GROUNDWATER INVESTIGATION DYNAMIC WORK STRATEGY .......................................................... 2-1
2.1 Investigation Approach .............................................................................................................. 2-1
2.2 Conceptual Site Model (CSM) .................................................................................................... 2-2
2.3 Decision Logic ............................................................................................................................ 2-3
2.4 Assessment of Potential Off-Site Sources ................................................................................. 2-4
3. METHODS AND PROCEDURES ............................................................................................................. 3-1
3.1 Field Preparation, Contracting, and Coordination .................................................................... 3-1
3.2 Recording Field Data .................................................................................................................. 3-1
3.3 Soil Gas Sampling ....................................................................................................................... 3-2
3.3.1 Passive Soil Gas Sampling ............................................................................................. 3-2
3.3.2 Active Soil Gas Sampling ............................................................................................... 3-3
3.4 CPT Soundings and MIP Testing ................................................................................................ 3-4
3.5 Manual Excavation .................................................................................................................... 3-5
3.6 Drilling Methods ........................................................................................................................ 3-5
3.6.1 Direct Push Technology ................................................................................................ 3-5
3.6.2 Hollow-Stem Auger ....................................................................................................... 3-6
3.6.3 Sonic ............................................................................................................................. 3-7
3.6.4 Dual-Wall Percussion Hammer ..................................................................................... 3-8
3.7 Lithologic Logging ...................................................................................................................... 3-8
3.8 Screening for Soil Contamination .............................................................................................. 3-9
3.9 Soil Samples Retained for VOC Analysis .................................................................................. 3-10
3.10 Grab Groundwater Sampling ................................................................................................... 3-10
3.11 Borehole Sealing ...................................................................................................................... 3-11
3.12 Permanent Isolation Casing for Groundwater Monitoring Wells ............................................ 3-11
3.13 Groundwater Monitoring Well Construction .......................................................................... 3-12
3.14 Groundwater Monitoring Well Development ......................................................................... 3-12
AMENDED
GROUNDWATER INVESTIGATION WORK PLAN
Former Lake Tahoe Laundry Works Site
1024 Lake Tahoe Boulevard, South Lake Tahoe, California
CONTENTS
EKI A70020.03 ii 19 March 2018
3.15 Groundwater Monitoring Well Sampling ................................................................................ 3-13
3.16 Surveying ................................................................................................................................. 3-14
3.17 Equipment Decontamination .................................................................................................. 3-14
3.18 Management of Investigation-Derived Waste ........................................................................ 3-15
3.19 Laboratory Analysis of Soil and Groundwater Samples for VOCs ........................................... 3-15
3.20 Quality Assurance/Quality Control Procedures ....................................................................... 3-16
3.20.1 Precision ..................................................................................................................... 3-16
3.20.2 Accuracy...................................................................................................................... 3-17
3.20.3 Sample Representativeness........................................................................................ 3-18
3.20.4 Completeness ............................................................................................................. 3-18
3.20.5 Comparability ............................................................................................................. 3-19
3.20.6 Sensitivity .................................................................................................................... 3-19
4. GROUNDWATER INVESTIGATION SCHEDULE ...................................................................................... 4-1
FIGURES
1 Site Location Map
EKI A70020.03 1-1 19 March 2018
1. INTRODUCTION
In accordance with Provision 2.1 of Cleanup and Abatement Order No. R6T-2017-0022 (“CAO” or “Order”),
this revised Groundwater Investigation Work Plan (“Work Plan”) proposes a groundwater investigation
for the former Lake Tahoe Laundry Works (“LTLW”) tenant space located at 1024 Lake Tahoe Boulevard
within the South Y area of South Lake Tahoe, California (“Site;” see Figure 1).
On 12 May 2017, the Water Board issued the Order to Seven Springs Limited Partnership (“Seven
Springs”), Fox Capital Management Corporation (“Fox”), Bobby Pages, Inc., and Connolly Development,
Inc. (collectively, the “Responsible Parties”), which pertains to contamination resulting from historical
releases of perchloroethylene (“PCE”) at the Site. Bobby Pages, Inc. and Connolly Development, Inc. have
not responded to the Order and have not participated in the development of this Work Plan.
Paragraph 2.1 of the Order requires the Responsible Parties to determine the lateral and vertical extent
of PCE and other chlorinated volatile organic compounds (“VOCs”) in groundwater originating from the
Site. This Work Plan presents a dynamic and iterative approach to further define the vertical and lateral
extent of groundwater contamination associated with the Site.
Seven Springs and Fox (collectively the “Working Parties”) submitted an initial Work Plan to the Water
Board for approval on 26 July 2017. The Water Board determined that initial Work Plan was incomplete
but conditionally accepted Phase I of the groundwater investigation described in the initial Work Plan.
The Water Board requested that other sections be modified to address its written comments 1 and that
the revised Work Plan be submitted for acceptance by the agency. The Water Board did not concur with
the conceptual site model (“CSM”), groundwater investigation work strategy, or schedule presented in
the Work Plan because, according to the Water Board, “those elements do not consider CAO findings or
comply with the requirement for a dynamic and iterative strategy to define the PCE plume.” 2
EKI Environment & Water, Inc. (“EKI”) revised the Work Plan following consultation with Water Board staff
and in light of input from South Tahoe Public Utility District (“STPUD”), Lukins Brothers Water Company,
Inc., and Tahoe Keys Property Owners Association (“TKPOA”), which are collectively referred to as the
“Stakeholders.” In particular, the initial Work Plan was revised to address comments provided by the
Water Board in its 11 August 2017 letter and subsequent email correspondence, 3 and those given orally
by the Water Board during a meeting with Seven Springs and Fox representatives on 22 August 2017 and
Stakeholders at the public information meeting held at Water Board offices on 23 August 2017.
1 See Water Board. 11 August 2017. Notice of Incomplete Submittal with Request for Revised Work Plan, Cleanup
and Abatement Order R6T-2017-0022, Lake Tahoe Laundry Works, South Lake Tahoe, El Dorado County, Site Cleanup
Program Case No. T6S043.
2 Id. p. 4.
3 Grey, B. (Water Board). 5 September 2017. Email to S. Reisch (Hogan Lovells) Re Informal Comments on Draft
Decision Tree.
EKI A70020.03 1-2 19 March 2018
The revised Work Plan was submitted to the Water Board on 11 September 2017. The Water Board
solicited Stakeholder review of the revised Work Plan until 10 October 2017. 4 The Stakeholders provided
comments on the revised Work Plan 5,6,7,8,9 to which the Working Parties responded in detail. 10
Following a meeting with Water Board staff on 24 January 2018 at which the parties discussed their
respective views of the Work Plan and its compliance with the Order, on 1 February 2018, the Water Board
issued a notice of continued non-compliance with the Order stating its reasons for concluding that the
Work Plan did not comply with the Order. 11
EKI has revised this Work Plan to address comments included in the Notice of Non-Compliance and to be
consistent with discussions between the Working Parties and Water Board staff during a meeting on
28 February 2018, and subsequent email correspondence and conference calls. As agreed during the
28 February 2018 meeting, EKI has simplified the Work Plan by removing items not requested under
Paragraph 2.1 of the Order.
4 Grey, B. (Water Board). 28 September 2017. Email to interested parties Re Lake Tahoe Laundry Works - Revised
Work Plan and Off-Site Groundwater Investigation Data Report.
5 STPUD. 10 October 2017. South Tahoe Public Utility District’s Comments on the Revised Groundwater Investigation
Work Plan, Former Lake Tahoe Laundry Works Site, CAO R6T-2017-0022. (“STPUD Revised Work Plan Comments”)
6 TRC Solutions, Inc. 27 September 2017. Comments on Revised Groundwater Investigation Work Plan, Lake Tahoe
Laundry Works Site. Prepared on behalf of Lukins Brothers Water Company, Inc.
7 TRC. 9 October 2017. Supplemental Comments on Revised Groundwater Investigation Work Plan, Lake Tahoe
Laundry Works Site. Prepared on behalf of Lukins Brothers Water Company, Inc. (“Lukins Revised Work Plan
Supplemental Comments”)
8 Ground Zero Analysis, Inc. 27 September 2017. Comments on the September 11, 2017 EKI Revised Groundwater
Investigation Workplan. Prepared for TKPOA. (“TKPOA Revised Work Plan Comments”)
9 Ground Zero Analysis, Inc. 24 October 2017. Additional information and comments on the September 11, 2007 EKI
Revised Groundwater Investigation Workplan. Prepared for TKPOA.
10 PES Environmental, Inc. (“PES”) and EKI. 11 January 2018. Responses to Comments Regarding Revised
Groundwater Investigation Work Plan, Former Lake Tahoe Laundry Works Site, 1024 Lake Tahoe Boulevard, South
Lake Tahoe, California. p. 2.
11 Water Board. 1 February 2018. Notice of Continued Non-Compliance with Cleanup and Abatement Order (CAO)
No. R6T-2017-0022, Lake Tahoe Laundry Works (LTLW), South Lake Tahoe, El Dorado County, Site Cleanup Program
Case No. T6S043. Letter to Responsible Parties from Scott C. Ferguson, PE, Supervising Water Resource Control
Engineer. (“Notice of Non-Compliance”) p. 2.
EKI A70020.03 2-1 19 March 2018
2. GROUNDWATER INVESTIGATION DYNAMIC WORK STRATEGY
Under the Order, the objective of the proposed groundwater investigation is to characterize the lateral
and vertical extent of VOCs originating from the Site to an individual concentration of 0.5 micrograms per
liter (“µg/L”). This Work Plan proposes a dynamic work strategy that is predicated on evaluating multiple
lines of evidence, such as site use history, preferential pathways, groundwater flow direction, subsurface
stratigraphy, evidence of releases (e.g., surface staining, reported disposal practices, and soil or soil gas
contamination), and lateral and vertical distributions of VOCs in groundwater.
2.1 Investigation Approach
According to the United States Environmental Protection Agency (“U.S. EPA”), a dynamic work strategy
allows data to be obtained in real time as part of an integrated field effort. The actual number of field
mobilizations depends on the complexity and constraints of a project but is always fewer than would be
required under a static work plan design. 12 Important features of a dynamic work strategy include:
• Flexible and adaptable approach to data collection that can be adjusted and refined in the field
as new data are obtained and data gaps are identified.
• Analytical quality control program that is also adaptive in nature, collecting quality control
samples that focus on the principal sources of uncertainty and incorporating real-time quality
control review of data. 13
• Clear decision logic that will be followed to guide dynamic work strategy. The decision logic is
intended to determine when: (1) full geometry of the chlorinated VOC plume attributable to the
release(s) at LTLW has been delineated, (2) VOC transport along preferential pathways must be
evaluated, (3) additional phases of investigation need to be conducted to address data gaps, and
(4) sampling methods and procedures must be modified to obtain representative data.
Unlike work plans developed under traditional approaches, U.S. EPA states a dynamic work strategy does
not attempt to identify all sample types, locations, and quantities at the outset of an investigation. 14 The
dynamic work strategy may identify general sampling approaches (e.g., statistical or judgmental) or initial
sampling locations within planning documents (e.g., work plan), but it leaves the details of the data
collection approach to be developed and adapted in the field. This adaptive strategy also extends to the
12 U.S. EPA. September 2005. Use of Dynamic Work Strategies Under a Triad Approach for Site Assessment and
Cleanup – Technology Bulletin. Office of Solid Waste and Emergency Response. EPA 542-F-05-008. (“U.S. EPA
Dynamic Work Strategies”) p. 1.
13 Quality assurance relates to how a process is performed, whereas quality control is more the inspection aspect
of quality management. Inspection refers to measuring, examining, and testing to confirm data obtained through
implementation of the Work Plan are usable.
14 U.S. EPA Dynamic Work Strategies. supra n. 12, p. 2.
EKI A70020.03 2-2 19 March 2018
analytical methods, quality assurance/quality control procedures, communication program, and other
project elements. 15
2.2 Conceptual Site Model (CSM)
Characterization of VOCs in groundwater is a dynamic and iterative process. Each additional phase of
investigation will be based upon the findings of all preceding phases of investigations that are used to
define the lateral and vertical extent of VOCs originating from the Site and refine the CSM. A CSM is a
scientifically defensible foundation for decision-making that evolves as site characterization progresses.
The Department of Toxic Substances Control (“DTSC”) states that the CSM process is necessarily
iterative.16 The CSM is updated as data are collected. 17 Site characterization is complete when the CSM
is sufficiently detailed for remedy evaluation and selection.
The Order does not require inclusion of a CSM in the Work Plan. Moreover, the Water Board states that
the CSM presented in previous versions of the Work Plan lacks sufficient information to support
development of investigation strategies and decision logic to satisfy Paragraph 2.1 of the CAO. 18 The
Stakeholders expressed similar viewpoints in their written comments on the Work Plan. The Stakeholders
recommend that existing data be used to establish the CSM and to delineate the existing groundwater
PCE plume, and geologic and hydraulic conditions in the South Y area. 19,20,21
Accordingly, the Working Parties are compiling lithologic information and chemical data needed to fulfill
Order requirements and to address Stakeholder concerns. The CSM will incorporate newly obtained data
(e.g., groundwater flow direction measured in on-Site monitoring wells and, potentially, off-Site
monitoring wells, and VOC concentrations detected in background/upgradient groundwater samples), as
well as other relevant existing data and hydrogeological analysis, including, but not limited to: estimated
range of groundwater flow velocity(ies), direction(s), and vertical gradients; lithology; mass removed;
effects of historical pumping; and groundwater chlorinated VOC concentration trends. The Working
Parties will present the CSM to the Water Board once it has been sufficiently developed to guide the
groundwater investigation.
15 Id.
16 DTSC. June 2012. Guidelines for Planning and Implementing Groundwater Characterization of Contaminated Sites.
(“DTSC Groundwater Characterization Guidelines”). p. 12.
17 Id.
18 Water Board Notice of Non-Compliance. supra n. 11, Enclosure 1, Water Board Staff Comments and
Recommendations on the Revised Work Plan. p. 4.
19 Lukins Revised Work Plan Supplemental Comments. supra n. 7, p. 1.
20 STPUD Revised Work Plan Comments. supra n. 5, p. 5.
21 TKPOA Revised Work Plan Comments. supra n. 8, p. 1.
EKI A70020.03 2-3 19 March 2018
2.3 Decision Logic
The groundwater investigation decision logic is as follows:
1. Perform depth-discrete groundwater sampling at on- and off-Site locations as guided by available
data (and CSM once it is developed) to further delineate lateral and vertical extent of VOCs in
groundwater originating from LTLW and to refine understanding of groundwater flow direction.
2. If the lateral (horizontal) extent of VOCs originating from Site has not been defined, collect
additional samples (i.e., grab groundwater and/or groundwater monitoring well samples) from
the area(s) downgradient from locations with VOC concentrations greater than 0.5 µg/L.
Additionally, if the vertical extent of VOCs has not been defined, collect additional samples deeper
within the aquifer. Continue with lateral and vertical assessment of VOCs originating from the
Site, as guided by the evolving CSM, until the lateral and vertical extent of the VOCs originating
from the Site has been defined to 0.5 µg/L. If sampling to delineate lateral and vertical impacts is
warranted on non-public properties, seek access to those properties from the relevant
landowner(s), and, if unsuccessful, document efforts made to obtain access and seek assistance
from the Water Board. Complete relevant sampling upon obtaining access.
3. Consider the potential for contaminant migration along man-made (e.g., inside pipelines or fill
surrounding subsurface utilities) or natural (e.g., high transmissivity deposits) preferential
pathways from the Site, and collect data to support or reject preferential pathway contaminant
transport as a means for impact of groundwater. If data support preferential pathway transport
of VOCs, collect additional samples from implicated area(s) until delineation of lateral and vertical
extent of VOC migration through such pathways from the Site.
4. If application of the source identification criteria described in Section 2.4 indicates that a
non-LTLW source of VOCs may be contributing VOCs to groundwater in excess of 0.5 µg/L, assess
the potential source through additional soil, soil gas, and/or groundwater sampling. As necessary
to accomplish this sampling, seek access to the potential source property from the relevant
landowner, and, if unsuccessful, document efforts made to obtain access and seek assistance
from the Water Board. Upon obtaining access, complete relevant sampling.
5. If an additional source of VOCs to groundwater appears to have been identified, present the
results to the Water Board for appropriate Water Board action.
6. Evaluate potential data gaps, determine scope of work to address any data gaps, and perform
additional investigations (e.g., CPT/MIP, grab groundwater sampling, groundwater monitoring
wells installation, etc.) and/or modeling to address any data gaps.
EKI A70020.03 2-4 19 March 2018
2.4 Assessment of Potential Off-Site Sources
Source characterization requires identifying the contaminants present, affected media, and
concentrations of contaminants in various media. 22 DTSC states potential sources of contamination
should be identified based on historical records of operations, aerial photographs, site reconnaissance,
and previous sampling, features, and site activities. 23,24 The Working Parties will review this information
as it relates to new data obtained through implementation of the Work Plan. Off-Site PCE sources, if any,
will be identified by applying the below source identification criteria:
• Site-specific information such as chemical use inventories, disposal records, soil samples with
detections of VOCs, and/or elevated VOC concentrations in soil gas samples;
• Site use history commonly associated with PCE applications, such as dry cleaning or degreasing
metal parts in conjunction with automotive and other metalworking operations;
• VOC concentrations in groundwater samples collected from locations downgradient of the
potential source are significantly higher than VOC concentrations in groundwater samples
collected in the same hydrogeological unit from locations upgradient of the potential source;
• Elevated VOC concentrations in samples of first-encountered shallow groundwater collected from
locations downgradient of the potential source; and
• Concentrations of VOCs in groundwater samples collected from locations downgradient of the
potential source that suggest the presence of dense non-aqueous phase liquid (“DNAPL”).
The Working Parties will use the results of the assessment of potential off-Site sources to further
understand groundwater conditions within the South Y area in accordance with Section 2.3 and to develop
the CSM.
22 DTSC Groundwater Characterization Guidelines. supra n. 16, p. 37.
23 Id.
24 DTSC. October 2015. Preliminary Endangerment Assessment Guidance Manual. pp. 75-77.
EKI A70020.03 3-1 19 March 2018
3. METHODS AND PROCEDURES
This section describes the methods and procedures that will be used to complete investigative activities
required by the Order. Activities described herein may be performed or coordinated by EKI, PES, or other
qualified company retained by the Working Parties.
3.1 Field Preparation, Contracting, and Coordination
Preparatory tasks related to each investigation phase will be completed before commencing field
activities. The company retained by the Working Parties to implement the investigation will perform the
below tasks, as appropriate:
• Arrange access to private property, as needed;
• Inspect proposed test and grab groundwater sampling locations to evaluate access constraints
and field logistics, and to mark planned test locations on pavement surfaces;
• Obtain an Encroachment Permit from City of South Lake Tahoe and/or California Department of
Transportation (“Caltrans”) for work planned on public streets or right-of-ways;
• Engage services of a traffic control contractor to prepare traffic control plans and to assist, as
needed, with preparation of an Encroachment Permit application with the City of South Lake
Tahoe and/or Caltrans for work planned on public streets or right-of-ways;
• Obtain a Drilling Permit from El Dorado County Environmental Management Department for
planned boreholes and monitoring wells;
• Prepare or update a Site-specific Health and Safety Plan for field personnel;
• Retain a private utility locating company to screen for the presence of buried utilities at the
planned test locations and accompany the locator in the field;
• Retain a firm, possessing a valid C-57 water well contractor license issued by the State of
California, to provide drilling and groundwater sampling services;
• Contact Underground Services Alert (“USA”) and coordinate with South Tahoe Public Utility
District representatives, City of South Lake Tahoe officials, and/or Caltrans representatives, as
needed, for clearance at each test location; and
• Coordinate with a California-certified analytical testing laboratory regarding delivery of sample
containers and transport of collected samples to the laboratory for subsequent analysis.
3.2 Recording Field Data
Observations and data obtained during field activities will be recorded in log books or on forms specific
to tasks being conducted (e.g., borehole log, monitoring well construction log, and monitoring well
EKI A70020.03 3-2 19 March 2018
purge/sample forms). Data entries will be performed in ink and with sufficient detail that a particular
situation or event is described sufficiently. If a change is needed to be made within a log book or form, a
single strikethrough line will be used to mark out incorrect information. The individual making the change
will initial and date the strikeout and correction.
Company personnel will calibrate field instruments according to manufacturer procedures. In general,
field instruments will be calibrated each day prior to use. In addition, prior to use, each instrument will be
checked for damage and contamination, and will be repaired or cleaned, as needed. Calibration records
shall include the following:
• Name of person calibrating instrument
• Instrument name, model, and serial number
• Date and time of calibration
• Standard(s) used
• Results of calibration (raw data and summary)
• Corrective actions taken, if appropriate
Personnel calibrating the instrument will be trained in its proper operation. The instrument calibration
will be checked after the final use at the end of the day. Instruments will be periodically checked during
the day by briefly exposing instruments (i.e., “bump test”) to the chemicals or parameters of interest to
verify that the sensors respond and the instruments function accordingly. Instruments will be maintained
and repaired in accordance with manufacturer specifications.
3.3 Soil Gas Sampling
Soil gas sampling provides measures of VOCs contained in air within interstitial spaces (i.e., pores) of soil,
as opposed to directly sampling the soil matrix above the groundwater surface (i.e., water table). 25 Soil
gas sampling may entail passive and/or active techniques.
3.3.1 Passive Soil Gas Sampling
Passive soil gas sampling can be an effective method to identify VOC source areas in the vadose zone and
delineate the extent of contamination. By collecting samples in a grid, the method allows for an increase
in data density and, therefore, provides a high-resolution depiction of the nature and extent of
contamination across the survey area. By comparing the results, as qualitative or quantitative, from one
location to another, the relative distribution and spatial variability of VOCs in the subsurface can be
25 The saturated zone is the zone below the water table in which the pores of sediments are completely filled with
water. The zone between ground surface and the water table is termed the unsaturated zone or vadose zone. The
unsaturated zone includes the capillary fringe and also may include localized perched groundwater.
EKI A70020.03 3-3 19 March 2018
determined, thereby improving the CSM. Areas of the site where no VOCs are detected can be removed
from further investigation, while subsequent sampling can be focused in areas determined from the
passive soil gas survey to be impacted.
Passive sampling devices containing an adsorbent material are placed in the subsurface and left to collect
VOCs. Sites having coarse-grained, dry soil, high VOC concentrations, shallow groundwater or soil
contamination or both, typically require shorter exposure periods. Sites with fine-grained, moist soil or
deep contaminant sources, typically require longer exposure periods. Exposure periods typically range
from days to weeks. VOCs are amassed onto the adsorbent material. The sampling devices are then
retrieved and transported to the laboratory for VOC analysis. Passive soil gas sampling will be conducted
in accordance with ASTM International (“ASTM”) Standard D7758 – 17. 26
3.3.2 Active Soil Gas Sampling
Soil gas probe installation and sampling procedures will be in accordance with DTSC guidance. 27 Soil gas
sampling will not be performed if significant precipitation (greater than ½ inch in a 24 hour period) has
occurred within the previous five days. The soil gas probe sample tubing will be connected from the Vapor
Pin™ probe barbed fitting or equivalent to the sample manifold system via threaded SwageLok™
connectors.
The Working Parties’ consultant will collect soil gas samples in laboratory prepared 1-liter capacity Summa
canisters. Prior to soil gas purging and sample collection, a vacuum leak shut-in test of the flow-
controller/gauge manifold assembly will be performed for a minimum of 2 minutes, with a maximum
allowable vacuum drop of 0.2 inches of mercury (“in Hg”). If the maximum allowable vacuum drop is
exceeded, the manifold fittings will be tightened or the manifold will be replaced and the shut-in test will
be redone. Vacuum gauge sensitivity will register a minimum of 0.2 in Hg. Prior to sample collection,
approximately three sampling system volumes of soil gas will be purged at a flow rate of approximately
150 to 200 milliliters per minute (“mL/min”) from each soil gas probe (approximately 200 mL per in Hg
vacuum). A 3-way valve (with the handle mounted outside the leak detection shroud) will be opened to
divert the flow of purged soil gas from the probe to the purge Summa canister, after opening the purge
Summa valve.
A leak detection test will be conducted using helium or other suitable gas (e.g., isopropyl alcohol or
difluoroethane) as a tracer inside a plastic shroud covering the entire sampling apparatus. 28 The tracer
gas will be infused into the shroud before purging and sample collection activities. Tracer gas
concentrations in purged soil gas may be monitored using a gas detection meter connected to the sample
tubing by a “T” fitting and 3-way valve. One ambient air sample per day will be collected using a 1-liter
26 ASTM. 1 June 2017. Standard Practice for Passive Soil Gas Sampling in the Vadose Zone for Source Identification,
Spatial Variability Assessment, Monitoring, and Vapor Intrusion Evaluations. Designation: D7758 – 17.
27 DTSC. July 2015. Advisory – Active Soil Gas Investigations. Prepared in collaboration with Los Angeles Regional
Water Quality Control Board and San Francisco Bay Regional Water Quality Control Board.
28 Id. Appendix C.
EKI A70020.03 3-4 19 March 2018
Summa canister inside the leak detection shroud during sampling of one soil gas probe to measure tracer
gas concentrations inside the shroud.
Flow rates of approximately 150 to 200 mL/min are used to fill the Summa canisters. The canisters are
filled to approximate 80 percent of capacity (approximately 5 in Hg vacuum remaining). All pertinent field
observations, pressure, times and readings are recorded. After filling and closing the sample valve, all
Summa canisters are removed from the manifold, labeled with sample information, including initial and
final vacuum pressures, placed in a dark container, and transported under chain-of-custody protocols to
a California-certified analytical laboratory. The analytical laboratory will record the final Summa canister
vacuum upon receipt.
3.4 CPT Soundings and MIP Testing
CPT soundings are conducted by hydraulically pushing a set of threaded steel pipes (“rods”) into the
ground using a heavy (15-30 ton) truck-mounted rig. The tips of the rods are equipped with a
pressure-sensitive electronic piezocone penetrometer. Measurements of tip resistance, sleeve resistance
(i.e., local friction), and dynamic pore water pressure are recorded as the piezocone is pushed through
the soil strata. Data are recorded on a continuous depth-versus-response plot that can be interpreted to
reveal grain-size and composition characteristics of the various soil units penetrated. CPT data can identify
the depths and thickness of likely permeable units from which grab groundwater samples can be obtained.
MIP provides semi-quantitative assessment of VOC concentrations in groundwater or saturated soil. MIP
consists of a downhole permeable membrane probe, a stream of carrier gas, and chemical detectors
[e.g., flame ionization detector (“FID”), photoionization detector (“PID”), and a halogen specific detector
(“XSD”)] at the surface. VOCs in groundwater diffuse across the membrane driven by a concentration
gradient, and partition into the carrier gas where they are moved to one or more chemical detectors. MIP
produces a log of detector response in microvolts versus depth of the probe, providing a continuous
measure of relative VOC concentrations with depth. MIP data can identify specific depths where the
highest VOC concentrations in groundwater are present, thus, targeting groundwater sample collection
at those depths.
MIP is capable of detecting PCE in groundwater if present at concentrations equal to or greater than
approximately 200 µg/L. 29,30 Different investigative methods will be required when delineating VOC
concentrations to MCLs or the analytical laboratory method reporting or quantitation limit of 0.5 µg/L for
individual chlorinated VOCs.
29 Geoprobe Systems. 2017. MIP FAQs. http://geoprobe.com/mip-faqs. Accessed 3 September 2017.
30 Ravella, M., R. Fiacco, Jr., J. Frazier, D. Wanty, and L. Burkhardt. 2007. Application of the Membrane Interface
Probe (MIP) to Delineate Subsurface DNAPL Contamination. Environmental Engineer: Applied Research and Practice.
Vol. 1.
EKI A70020.03 3-5 19 March 2018
3.5 Manual Excavation
Mechanical drilling equipment will not be used to expose buried utilities for the purpose of sampling fill
surrounding the lines. The State of California Government Code defines a tolerance zone that refers to
24 inches from each side of a field marking denoting the presence of a subsurface installation [Cal Gov
Code §4216(u)]. According to Cal Gov Code §4216.4 (a)(1), manual excavation shall be employed to
determine the exact location of a subsurface installation before using any power-driven excavation or
boring equipment within the tolerance zone of the subsurface installation. Manual excavation may be
performed with hand tools (e.g., shovels, axes, picks), or with “air” or “hydo” excavation that utilize
compressed air or water, respectively, to dislodge soil without damaging buried utilities or other
infrastructure.
The company retained by the Working Parties shall obtain all necessary permits and will coordinate its
activities with the owners of the buried utilities. Surface materials covering the utilities shall be replaced
as directed by the owners of the buried utilities and owners of properties under which the sections of
utilities excavated are situated, if different from the owners of the buried utilities.
3.6 Drilling Methods
Various methods, including direct push technology, hollow-stem auger, sonic technology, or dual-wall
percussion hammer, may be used to complete boreholes for accomplishing soil sampling or constructing
monitoring wells. The drilling method will depend upon the objectives of the investigation, and the need
to minimize the potential for downward vertical migration of VOC-containing groundwater, and DNAPL in
the subsurface. The company retained by the Working Parties shall be responsible for selecting the
appropriate drilling method for a particular investigation phase.
The purpose of collecting soil samples is to acquire samples that are representative of subsurface
conditions. How well this purpose is met is determined in part by soil core recovery (i.e., percentage of
attempted sample length that is actually obtained). Sample recovery depends on the interaction of drilling
and sampling procedures with the specific characteristics of subsurface sediments. Company personnel
will be responsible for working with drillers to maximize soil core recovery. Changing sampling tools,
adding sand catchers, varying drilling or sampling rates, and/or adjusting the sample interval length may
be required to improve sample recovery.
3.6.1 Direct Push Technology
Direct push technology is preferred when subsurface conditions allow use of a Geoprobe® or similar type
rig because soil sampling is expedited and the amount of investigation-derived waste is minimized.
However, direct push technology may not be feasible if soil samples are to be obtained at depths greater
than 150 feet bgs, or if coarse, consolidated, cemented, or lithified deposits are encountered.31
31 DTSC Groundwater Characterization Guidelines. supra n. 16, p. 48.
EKI A70020.03 3-6 19 March 2018
Direct push technology (also known as “direct drive,” “drive point,” or “push technology”) refers to a
group of tools used for performing subsurface investigations by driving or pushing, small-diameter hollow
steel rods into the ground. Direct push technology allows for cost-effective, rapid sampling and data
collection from unconsolidated sediments. 32 The drill stem and bit can be advanced using a hammer or
the weight of the vehicle to which it is mounted. Continuous soil cores and discrete groundwater and soil
gas samples can be collected. Direct push technology equipment is highly mobile and can be small enough
for access within buildings.
Drag-down of contamination is considered to be less of a problem with direct push technology than with
conventional well drilling techniques, such as hollow-stem auger, where contaminants have a better
chance of sticking to the augers as they advance. 33 As direct push technology rods are advanced, the
action of pushing the drive rods generally wipes away sediments through which the rods have already
passed.
Care must be taken to avoid creating conduits that allow downward flow of groundwater and
contaminants along the borehole annulus (i.e., space between borehole wall and direct push technology
hollow steel rods). Hydraulic conduits are of particular concern when the borehole intercepts previously
unconnected permeable units, or when DNAPL is present that can migrate downward along the conduit.
Techniques recommended by DTSC or U.S. EPA will be followed to minimize the borehole annulus. These
techniques include using dual tube soil sampling systems, employing a drive tip that is the same diameter
or smaller than the rods, and using rods and samplers with the same diameter. 34
3.6.2 Hollow-Stem Auger
The hollow-stem auger method consists of a truck-mounted drill rig that rotates tubular steel augers into
the subsurface. The augers have a hollow axle with steel flights spirally welded on the outside. A hollow
drill bit is attached to the first or lead hollow-stem auger that is advanced into the ground. The hole in this
bit is plugged during drilling with a blank steel plug or a continuous core barrel sampler. As the augers are
rotated into the ground, the sediments encountered in the middle of the borehole are forced into the
continuous core barrel sampler (unless a blank steel plug has been inserted), and the sediments
encountered on the outer edges of the bit and lead auger are cut and conveyed to the ground surface by
the outer flights of the auger. The sampler is connected to steel drill rods or cable and is extracted from
the lead auger whenever a new section of auger is added (typically every 5 feet) or more often depending
on the soil sampling procedures and recovery success experienced. Soil cuttings generated during drilling
activities will be temporarily stored on-Site in roll-off bins, tri-wall boxes, or 55-gallon drums until
32 DTSC June 2013. Drilling, Logging, and Sampling at Contaminated Sites. (“Drilling at Contaminated Sites”) p. 10.
33 U.S. EPA. August 2005. Groundwater Sampling and Monitoring with Direct Push Technologies. Solid Waste and
Emergency Response. EPA 540/R-04/005. p. 40.
34 Id. p. 41.
EKI A70020.03 3-7 19 March 2018
arrangements are made for proper disposal. Maximum depth of drilling is approximately 200 to
300 feet bgs. 35
The hollow-stem augers keep the borehole open, which allows soil sampling and monitoring wells to be
constructed inside of them. While drilling with a hollow-stem auger rig, soil samples for lithologic logging
and chemical analysis will be collected in a split-spoon sampler or similar device that is advanced ahead
of the augers in accordance with ASTM D1586-11. 36 The hollow-stem augers act as a temporary casing
to minimize downhole contamination of samples by sloughing of material from borehole walls. The
split-spoon sampler may be used with or without liners. The number of blows applied to the split-spoon
sampler to drive it each 6-inch depth increment is counted and recorded on the borehole log form.
Drilling progress using hollow-stem auger in sand formations can be affected by heaving of formation
sediments. Heave occurs as a result of hydrostatic pressures forcing sand inside the augers. The presence
of sand in the augers limits the ability to insert a sampler to the bottom of the augers to obtain a sample
of undisturbed material ahead of the auger. Alleviating heaving sand inside the auger will depend on the
purpose of the borehole. If the borehole is being drilled to obtain soil samples, then the augers will be
raised to allow them to empty. Afterwards, the augers will be flooded with clean, potable water to
surcharge the formation sediments at the lead auger tip. Drilling will continue to the depth where the soil
sample is desired. If no sampling is required and the borehole is being drilled to construct a monitoring
well, then the augers will be removed from the borehole and a wooden or Teflon knock-out plug will be
attached to the bottom of the lead auger. When the target depth is reached, the plug will be dislodged
and the monitoring well will be constructed.
3.6.3 Sonic
Sonic drilling employs use of high frequency resonant energy to advance a core barrel and casing into
subsurface formations. Sonic drill rigs can penetrate cobbles, boulders, and rock. Direct push technology
or hollow-stem auger may be favored over sonic if the objective is to observe detailed lithology or
measure VOC concentrations in soil samples. Soil samples can be distorted when extruding them from the
sonic core barrel. The sonic method also can create elevated temperatures, which may promote loss of
VOCs from soil samples. 37 Sonic technology may be desired when drilling deeper than 150 feet bgs or
investigating areas where DNAPL is suspected. Sonic technology employs telescopic casing, which
minimizes the potential for cross-contamination when constructing monitoring wells through confining
layers separating permeable units. 38
35 DTSC Drilling at Contaminated Sites. supra n. 32, p. 8.
36 ASTM International. 2011. Standard Test Method for Standard Penetration Test (SPT) and Split-Barrel Sampling
of Soils. ASTM D1586-11.
37 DTSC. Drilling at Contaminated Sites supra n. 32, p. 9.
38 DTSC states that direct push technology single-wall and dual-walled probes, CPT and MIP real-time measurement
tools, and Hydropunch™ samplers also are suitable for penetrating confining layers. Id. pp. 4-5.
EKI A70020.03 3-8 19 March 2018
The sonic method involves drilling a nominal 8-inch diameter borehole to the base of the target permeable
unit. A hydraulically powered drill head transmits rotary power, hydraulic down pressure, and vibratory
power directly to dual-wall steel drill pipe. The dual-wall drill pipe consists of a 6-inch diameter inner core
barrel and 8-inch diameter outer drive casing. The inner core barrel will be advanced ahead of the drive
casing to provide continuous core samples to the total depth of the borehole. The outer drive casing is
then advanced to prevent collapse of the borehole wall and to facilitate construction of groundwater
monitoring wells. Soil cuttings generated during drilling activities will be temporarily stored on-Site in
roll-off bins, tri-wall boxes, or 55-gallon drums until arrangements are made for proper disposal.
The sonic method is generally recognized as effective for minimizing the potential for hydraulic
communication between separate permeable units during borehole drilling. However, a potential exists
for the method to form irregular surfaces (or cavities) along the borehole wall under some lithologic
conditions (e.g., gravel or conglomerate zones). Accordingly, the need to implement additional measures
to minimize hydraulic communication between permeable units will be assessed during field activities
based on: (1) occurrence and nature of permeable units; (2) borehole lithology; and (3) drilling conditions.
If deemed appropriate and warranted, the procedures to minimize the potential for the borehole wall to
provide a conduit for hydraulic communication during drilling will include one of the following:
• Installing a temporary bentonite seal at the base of the shallow permeable unit. The temporary
bentonite seal will be completed by raising the drill pipe approximately 5 feet and placing
bentonite grout within the open borehole beneath the drill pipe. Drilling then will continue
through the bentonite grout leaving a 5-feet thick bentonite seal between the drive casing and
borehole wall at the base of the shallow permeable unit; or
• Converting to a smaller diameter drill bit and drive casing at the base of the shallow permeable
unit. This procedure will involve leaving the larger 8-inch diameter drive casing in place across the
shallow permeable unit to serve as a temporary seal during drilling and “telescoping” down to a
nominal 6-inch diameter drill pipe inside the larger diameter drive casing.
3.6.4 Dual-Wall Percussion Hammer
The dual-wall percussion hammer method will consist of driving a drill string of nominal 6-inch inside
diameter by 10-inch outside diameter dual-wall steel pipe using an above-ground pile hammer.
Compressed and filtered air is circulated down the annular space between the 10-inch and 6-inch
diameter pipes and returns to the surface along with soil cuttings through the inside of the 6-inch diameter
pipe. Soil cuttings are continuously returned to the surface with air through a cyclone separator. Soil
cuttings generated during drilling activities will be temporarily stored on-Site in roll-off bins or 55-gallon
drums until arrangements are made for proper disposal.
3.7 Lithologic Logging
Borehole logs will be prepared under the supervision of a State of California-licensed Professional
Geologist to document subsurface conditions encountered during drilling operations. Borehole logs for
EKI A70020.03 3-9 19 March 2018
natural undisturbed soil will include the following descriptions of sediment texture, fabric, structure,
moisture content, and color:
• Unified Soil Classification System (“USCS”) group symbols [e.g., SM (silty sand)] of primary soil
components or dual and borderline symbols
• Name and adjective narrative of primary, secondary, and minor grain size components
• Relative density for non-cohesive soil or consistency for cohesive soil
• Gradation and soil structure for non-cohesive soil or structure and plasticity for cohesive soil
• Moisture condition
• Color
• Other observations such as presence of stains or odors and VOC field measurements
(e.g., headspace analysis) using a hand-held PID or FID
Descriptions of fill materials are similar to those of natural undisturbed soil except that they are identified
as fill and not classified by a USCS group, relative density, or consistency.
Descriptions include the relative angularity, roundness, and sorting of particles, as well as their grain size
range. Sediment classification will be standardized to the grade scale described by Wentworth. 39
Soil texture will be classified according to the USCS. Descriptions of soil fabric and structure should include
whether the particles are flat or bulky and whether the particles are stratified, laminated, varved, etc. The
size, type, and condition of rock fragments, if present, also should be included (e.g., granite, basalt,
sandstone, limestone, decomposed and friable, etc.). Description of moisture content includes terms such
as dry, moist, or wet.
Soil color descriptions will reference Munsell color charts. Variations in color (e.g., mottling) can provide
information on the extent of groundwater table fluctuations and geochemical conditions (e.g., aerobic or
anaerobic) or formation changes. Color changes may indicate the presence of contaminants. For example,
soil may become darker in a reducing environment (“gleying”) caused by the presence of petroleum
hydrocarbons. Final versions of borehole logs to be included in reports shall be prepared using a
commercially available geologic software package.
3.8 Screening for Soil Contamination
During borehole logging, soil samples will be screened for VOCs using a calibrated hand-held organic vapor
meter (“OVM”). The OVM will be used to screen soil core as it is removed from the sampling device. At
39 Wentworth, C. 1922. A Scale of Grade and Class Terms for Clastic Sediments. Journal of Geology. Vol. 30.
pp. 377-392.
EKI A70020.03 3-10 19 March 2018
1-foot lengths along the core, the OVM reading will be recorded. At the discretion of the company’s
geologist, individual soil samples may be monitored for headspace. To obtain headspace readings, soil
samples will be placed in small re-sealable plastic bags for approximately 10 minutes and the headspace
will be monitored using the OVM. OVM readings will be recorded in the field and may be used to aid
selection of samples for laboratory analysis. The OVM may be either a hand-held FID, or PID equipped
with a minimum 10.6 electron Volt (“eV”) lamp, as the ionization potential for PCE is 9.32 eV. 40
The geologist also will inspect each soil core for visible evidence of potential soil contamination. This
examination will include color changes due to gleying, as described in Section 3.7. The soil core also will
be inspected for the presence of DNAPL and a separate recording of specific DNAPL-related field
observations will be made on the borehole log. A field aid that may be used to help identify DNAPL
presence is a shake test. This test involves mixing an aliquot of soil with water and a small amount of
hydrophobic dye powder such as Oil Red O. DNAPL will turn a separate color if present. A soil sample will
be collected for chemical analysis, as described in Section 3.9, if visual signs of contamination are noted
or elevated OVM readings are obtained.
3.9 Soil Samples Retained for VOC Analysis
Soil samples retained for laboratory analysis of VOCs will be collected utilizing EnCore™, Terra Core
samplers, or field preserved in 40-milliliter volatile organic analysis (“VOA”) vials, in accordance with
U.S. EPA Method 5035. 41 Soil samples retained for chemical analysis will be labeled and placed in a
chilled cooler and couriered or overnight air shipped to a California-certified analytical testing laboratory
under chain-of-custody protocols the same day or following day the samples are collected.
3.10 Grab Groundwater Sampling
Depth-discrete grab groundwater samples will be collected at the designated depth intervals using a
Hydropunch-type sampling technique. This technique involves advancing a water-tight assembly of
threaded drill pipe (“water rods”) with a short (e.g., 4-foot long) internal section of slotted polyvinyl
chloride (“PVC”) screen attached to an expendable steel cone tip. The tip fits into the rods with an O-ring
seal, preventing inflow of groundwater as the rods are advanced. After hydraulically pushing the rods to
the targeted sampling depth, the rods are checked to ensure that the interior is dry. The rods are then
retracted to expose the internal PVC screen, allowing groundwater to flow into the rods at the target
depth interval. Sampling will be accomplished using stainless-steel bailers decontaminated between
sampling events using a hot-water pressure washer and/or Liquinox solution, followed by a double
potable-water rinse. Alternatively, weighted disposable polyethylene bailers may be used; one per
sample. Downhole rods will be decontaminated using the procedures described in Section 3.17. Grab
40 National Institute for Occupational Safety and Health (“NIOSH”). 11 April 2016. NIOSH Pocket Guide to Chemical
Hazards. https://www.cdc.gov/niosh/npg/npgd0599.html. Accessed 1 September 2017.
41 U.S. EPA. December 1996. SW-846 Test Method 5035: Closed-System Purge-and-Trap and Extraction for Volatile
Organics in Soil and Waste Samples. https://www.epa.gov/hw-sw846/sw-846-test-method-5035-closed-system-
purge-and-trap-and-extraction-volatile-organics-soil. Accessed 1 September 2017.
EKI A70020.03 3-11 19 March 2018
groundwater samples at 5 feet bgs or shallower, or from fill surrounding utilities will be collected using
the above methods or obtained with a Teflon™ bailer.
Grab groundwater samples will be collected into laboratory-supplied glass containers (i.e., 40-milliliter
VOAs), preserved as appropriate for the analyses to be performed. The samples will be labeled and placed
in a chilled cooler and couriered or overnight air shipped to a California-certified analytical testing
laboratory under chain-of-custody protocols the same day or following day the samples are collected.
3.11 Borehole Sealing
After collecting soil and grab groundwater samples, boreholes that will not be converted to monitoring
wells will be decommissioned by sealing them to avoid creating conduits for contaminant migration,
either from the surface to the subsurface or between permeable units. The objective of sealing a borehole
is to prevent migration of contaminants through the borehole.
Each borehole will be sealed by retraction grouting. This method allows the water rods to act as a tremie
pipe for grout that is placed in the borehole, which facilitates complete sealing of the borehole. Retraction
grouting involves pumping a high-solids bentonite slurry or a neat cement grout through the rod and tool
string and out the bottom of the sampling tool as the tool is withdrawn from the hole. To use this method,
a port is needed at the end or sides of the tool and/or an expendable tip is necessary on the terminal end
of the tool through which the grout can be pumped. Retraction grouting is generally considered the most
reliable borehole sealing technique. 42
3.12 Permanent Isolation Casing for Groundwater Monitoring Wells
Permanent isolation casing will be used for monitoring wells that are to be constructed to depth intervals
beneath confining layers or an identified DNAPL zone to prevent the downward vertical migration of
contaminants. A nominal 10- to 12-inch diameter borehole for installation of isolation casing will be
advanced to a depth of at least one-foot beneath the identified DNAPL zone.
The isolation casing shall consist of 6-inch diameter low carbon steel. Sections of the casing shall be
threaded or welded together. The casing will be fitted with a drillable plug and welded, as needed. The
casing will be set by driving it approximately one or more feet into the confining layer or one or more feet
deeper than the bottom of the DNAPL zone. The top of the casing will be no higher than approximately
2 feet bgs.
The driller will form a seal to reduce the potential for grout seepage into the isolation casing by pouring
approximately 2 feet of bentonite chips into the casing after its placement and adding water to hydrate
the seal. The entire annular space between the casing and borehole wall will be grouted using neat cement
or cement/bentonite mixture. The driller will seal the annular space by placing grout with a tremie pipe
starting from the bottom of the borehole and finishing at ground surface.
42 DTSC Drilling at Contaminated Sites supra n. 32, p. 3.
EKI A70020.03 3-12 19 March 2018
3.13 Groundwater Monitoring Well Construction
Groundwater monitoring wells will be constructed using 2-inch diameter or 4-inch diameter new stainless
steel or PVC blank casing, with flush-joint threaded connections and 2-inch diameter or 4-inch diameter
wire-wrapped 0.020-inch aperture stainless steel well screens or 0.020-inch aperture factory-slotted PVC
well casing. The lower end of stainless steel screens will be closed with a welded plate or threaded plug
equipped with O-rings. The lower end of PVC well screens will be plugged with a threaded end cap
equipped with O-rings, or a slip cap permanently attached to the screen using three stainless steel screws.
No solvents or glues will be used. The top of the well casing will be set no higher than approximately
1 foot bgs.
A continuous filter pack will be placed in the annular space between the screen and borehole wall. The
well casing will be suspended in the borehole during filter pack placement. The filter pack will consist of
pre-washed, graded, packaged #3 silica sand or equivalent. Following placement of the filter pack, the
well will be swabbed to facilitate sand settlement, and additional sand will be added as necessary. Levels
of all annular space materials except grout will be continuously monitored using a weighted tape during
filling activities. Hollow-stem augers, or sonic or dual-wall percussion hammer casing will be slowly
withdrawn as annular materials are placed, and sonic casing will be vibrated as it is withdrawn. The depth
to top of sand will be confirmed, and topped off if necessary, after augers or casing are withdrawn above
the level of sand.
Above the filter pack, a transition seal of bentonite pellets or chips will be placed and hydrated (if above
groundwater surface), and neat cement grout will be placed using a tremie pipe, from the top of transition
seal to the planned depth of surface completion. Traffic-rated well vaults will be used for surface
completion of wells, and will be set in concrete, with the rim level set slightly above grade.
3.14 Groundwater Monitoring Well Development
Following construction of each monitoring well, grout and concrete will be allowed to cure for at least
72 hours. After curing, the well will be developed to remove fine-grained materials inside the filter pack
and casing, to stabilize the filter pack around the well screen, and to help produce more representative
samples from the water-bearing zone. Bailing, pumping, surging, swabbing, or a combination of these
methods will be used to develop the wells. The particular methods of development used will depend on
the yield of the well being developed.
A pump-service and well development rig will be used for development. The well will be checked with a
weighted tape, to confirm total casing depth and estimate the level of sediment accumulated in the
bottom of the well, if any. Excess sediment will be bailed from the well before surging.
Using a surge block with a soft rubber flange sized to fit snugly inside the vertical rods for wire-wrapped
screens or inside surface for slotted screens of the perforated casing, the well will be surged in stepwise
fashion, starting at the top of the screen, and moving toward the bottom. Surging will be accomplished
using smooth 2 to 4 foot long strokes.
EKI A70020.03 3-13 19 March 2018
After surging the entire screen, the surge block will be removed, and the well will be bailed or pumped to
remove sediment and water. The well will be alternately surged and pumped or bailed in this manner until
one of the following development criteria have been met:
• Field parameters have stabilized for three successive readings at 5 minute intervals, according to
the criteria provided below;
Parameter Maximum Change Between Measurements
pH +/- 0.1 pH unit
Temperature +/- 0.2 ⁰C
Conductivity +/- 3%
Dissolved Oxygen (“DO”) +/- 10% (if practicable)
Oxidation/Reduction Potential (“ORP”) +/- 10 mV
Turbidity
+/- 10% or a final value of less than
10 nephelometric turbidity units (“NTU”)
• At least 10 casing volumes have been removed; or
• The well dewaters and after 30 minutes has not recovered enough to allow additional surging or
bailing. Redevelopment of the well will be performed if conditions indicate that such action may
improve the ability of the well to provide representative, unbiased chemical and hydraulic data.
3.15 Groundwater Monitoring Well Sampling
Monitoring wells will not be sampled until at least 72 hours have elapsed since development. Before
sampling, the groundwater level in the well will be measured using a water level meter. The groundwater
level will be measured to the nearest 0.01 foot from the designated reference point on top of the PVC
well casing.
Groundwater samples will be collected using low-flow sampling techniques, as described by DTSC 43 and
U.S. EPA. 44 A bladder or submersible pump, and new polyethylene tubing will be used to purge and
sample each monitoring well at a flow rate of approximately 100 to 200 milliliters per minute (“mL/min”).
During purging, drawdown in the monitoring well and field parameters listed in Section 3.14 will be
measured at least every five minutes. Purging will be considered complete when field parameters have
stabilized as specified in Section 3.14 or when three casing volumes had been removed from the well.
43 DTSC. February 2008. Representative Sampling of Groundwater for Hazardous Substances, Guidance Manual for
Groundwater Investigations.
44 U.S. EPA. April 1996. Ground Water Issue: Low Flow (Minimal Drawdown) Groundwater Sampling Procedures.
Office of Research and Development. EPA/540/S-95/504.
EKI A70020.03 3-14 19 March 2018
The monitoring well will be sampled at the approximate flow rate used to purge the well. Groundwater
will be collected directly into laboratory-supplied glass containers (i.e., 40-milliliter VOAs), preserved as
appropriate for the analyses to be performed. The samples will be labeled and placed in a chilled cooler
and couriered or overnight air shipped to a California-certified analytical testing laboratory under
chain-of-custody protocols the same day or following day the samples are collected.
3.16 Surveying
Elevations and horizontal coordinates of groundwater monitoring wells will be established by a
California-licensed land surveyor. Vertical elevations will be surveyed relative to mean sea level based on
the North American Vertical Datum (“NAVD”) of 1988. Horizontal coordinates will be surveyed relative to
the California State Plane Zone 2 Coordinate System with the North American Datum (“NAD”) of 1983, as
realized by U.S. Department of Commerce National Oceanic and Atmospheric Administration (“NOAA”)
National Geodetic Survey (“NGS”) Continuously Operating Reference Station (“CORS”) in 2011.
Positions of boreholes and other temporary sample locations will be surveyed, if practicable; otherwise,
consistent with DTSC guidance, 45 the locations will be established by: (1) measuring distances from
permanent improvements such as streets, buildings, utility poles, or similar infrastructure; or (2) using
differential global positioning system (“DGPS”) receivers. DGPS involves the cooperation of two receivers,
one that is stationary and another that is roving making position measurements. DPGS provides improved
location to the global positioning system (“GPS”).
3.17 Equipment Decontamination
All downhole drilling and reusable sampling equipment will be cleaned upon mobilization to the South Y
area and between uses at different locations. Company personnel will inspect equipment for cleanliness
prior to use.
A three-stage decontamination process consisting of: (1) an initial potable water rinse, (2) an Alconox or
similar wash, and (3) a final distilled water rinse will be used for drilling and reusable sampling equipment.
Decontamination of equipment will be conducted at temporary decontamination pads established at
LTLW or other suitable locations.
Downhole drilling and reusable sampling equipment to be decontaminated will be transported to the
decontamination pad, as needed, and will be temporarily contained in plastic sheeting during transport.
Following decontamination, the clean equipment will be wrapped in new plastic sheeting until use.
Following completion of drilling activities at each location, company personnel will inspect the drilling rig
to determine if the rig shows signs of contact with potentially impacted soil and requires decontamination
prior to moving to the next drilling location. Any portion of the rig that comes in contact with
contaminated materials will be cleaned. Decontamination of the rig will be performed by: brushing with
non-phosphate detergent solution, as necessary, to remove foreign matter; (2) washing with a high
45 DTSC Drilling at Contaminated Sites. supra n. 32, p. 2.
EKI A70020.03 3-15 19 March 2018
pressure hot wash using a non-phosphate detergent/potable water solution; and (3) rinsing thoroughly
with potable water.
3.18 Management of Investigation-Derived Waste
Soil cuttings resulting from drilling operations will be stored in roll-off bins, tri-wall boxes, or 55-gallon
drums. Groundwater generated during development or purging of monitoring wells will be containerized
in 55-gallon drums or temporary tanks. Drums, roll-off bins, and temporary tanks containing investigation-
derived waste will be stored at LTLW until the waste is disposed at an off-site permitted waste
management facility.
A label with the following information will be applied to each investigation-derived waste (“IDW”)
container:
• Generator or representative contact information
• Container identification (“ID”) number
• Date(s) IDW was generated
• Location(s) where IDW was generated
• IDW description [e.g., used personal protective equipment (e.g., nitrile gloves, Tyvek™ overalls),
decontamination liquids and solids, soil cuttings, monitoring well development and/or purge
water]
The Working Parties will arrange for removal and off-Site disposal of investigation-derived waste.
Disposition of investigation-derived waste will be described in technical memoranda or reports submitted
to the Water Board.
3.19 Laboratory Analysis of Soil and Groundwater Samples for VOCs
Soil and groundwater samples will be analyzed for VOCs by U.S. EPA Method 8260 by a California-certified
analytical testing laboratory. Samples will be analyzed on a standard turnaround time from receipt of the
samples at the laboratory. Section 3.20 describes quality assurance/quality control procedures that will
be performed to confirm data obtained as part of this Work Plan are scientifically defensible, properly
documented, of known quality, and meet investigative objectives.
EKI A70020.03 3-16 19 March 2018
3.20 Quality Assurance/Quality Control Procedures
Consistent with U.S. EPA guidance, overall usability of the data for the investigation will be assessed by
evaluating the precision, accuracy, representativeness, comparability, completeness, and sensitivity of
the data set. 46
3.20.1 Precision
Precision of field sample collection will be evaluated by assessing the relative percent difference (“RPD”)
data from field duplicate samples. Field duplicates are a second sample collected at the same time as the
investigative (i.e., original) sample using identical sampling techniques. For grab groundwater sampling,
field duplicates will be collected at a 10 percent frequency of all grab groundwater samples collected. 47
At a minimum, one duplicate sample will be collected for each grab groundwater sampling event. For
groundwater monitoring well sampling, one field duplicate will be collected for each monitoring event.
Field duplicates will be analyzed for the same VOCs as the original sample. A RPD of 30 percent will be
used as an advisory limit for VOCs detected in both the investigative and field duplicate groundwater
samples at concentrations greater than or equal to 5 times their quantitation limits (i.e., analytical method
reporting limits).
Analytical precision will be evaluated by assessing the RPD data from duplicate spiked sample analyses or
duplicate laboratory control sample (“LCS”) analyses. The RPD between two measurements is calculated
using the following formula:
RPD = |R1- R2| �(R1+ R2)
2 � x 100
where:
R1 = value of first result
R2 = value of second result
RPD data will provide the means to evaluate the overall variability attributable to the sampling procedure,
sample matrix, and laboratory procedures. The RPD of two measurements can be high when the
concentrations approach the quantitation limit of an analysis. RPDs will be calculated only when the
concentrations of a chemical detected in both samples are greater than or equal to 5 times the
quantitation limit for the chemical.
46 See U.S. EPA. July 2014. SW-846 Compendium: Project Quality Assurance and Quality Control, U.S. EPA.
December 2002. Guidance for Quality Assurance Project Plans, EPA QA/G-5. Office of Environmental Information.
EPA/240/R-02/009, and U.S. EPA. March 2001. EPA Requirements for Quality Assurance Project Plans, EPA QA/G-5.
Office of Environmental Information. EPA/240/B-01/003.
47 U.S. EPA. May 2014. Sampling and Analysis Plan Guidance and Template. Version 4, General Projects.
R9QA/009.1. p. 58.
EKI A70020.03 3-17 19 March 2018
3.20.2 Accuracy
Data from method blank samples, equipment and trip blank samples, matrix spike/matrix spike
duplicate (“MS/MSD”) samples, surrogate compound spikes, and LCSs will be used to determine accuracy
and potential bias of the sample data.
Data from method blank samples provide an indication of laboratory contamination that may result in
bias of sample data. Sample data associated with method blank contamination will have been identified
during the data verification/validation process. Sample data associated with method blank contamination
are evaluated during the data validation procedure to determine if chemicals detected in samples
associated with contaminated method blanks are “real” or are the result of laboratory contamination. The
procedure for this evaluation involves comparing the concentration of the chemical in the sample to the
concentration in the method blank sample taking into account adjustments for sample preparation and
dilution factors. In general, sample data are qualified as not detected if the sample concentration is less
than 5 times (10 times for common laboratory contaminants) the method blank concentration. If the
affected sample result is less than the quantitation limit, the quantitation limit will be reported. If the
affected sample result is greater than the quantitation limit, the quantitation limit will be elevated to the
concentration detected in the sample.
Data from equipment and trip blank samples provide an indication of field conditions that may result in
bias of sample data. The evaluation procedure and qualification of sample data associated with equipment
and trip blank contamination is performed in a similar manner as the evaluation procedure for method
blank sample contamination.
Equipment blank results will be used to assess the effectiveness of equipment decontamination. An
equipment blank consists of distilled water poured over or pumped through equipment and into sample
containers. Equipment blanks will be collected at a 5 percent frequency of all grab groundwater samples
collected and at a frequency of 5 percent of all newly installed monitoring wells and will be analyzed for
VOCs.
Trip blanks are used to assess the potential introduction of contaminants resulting from sample handling
or shipment. Trip blanks are prepared by the analytical laboratory and consist of VOA vials filled with
laboratory water in the laboratory. Trip blanks are sent to the site with the sample containers, kept with
samples during sample collection, and shipped back to the laboratory for analysis with the collected
samples. For grab groundwater sampling, one trip blank will be submitted per batch of water samples and
will be analyzed for VOCs. For groundwater monitoring well sampling, one trip blank will be collected for
each monitoring event and will be analyzed for VOCs.
Matrix spike sample data provide information regarding the accuracy of the analytical methods relative
to the sample matrix. Matrix spike samples are field samples that have been fortified with target
compounds prior to sample preparation and analysis. The percent recovery data provide an indication of
the effect that the sample matrix may have on the preparation and analysis procedure. Sample data
exhibiting matrix effects will have been identified during the data verification/validation process.
EKI A70020.03 3-18 19 March 2018
Surrogate spike recoveries provide information regarding the accuracy/bias of organic analyses on an
individual sample basis. Surrogate compounds are not expected to be found in the samples and are added
to every sample prior to sample preparation. The percent recovery data provide an indication of the effect
that the sample matrix may have on the preparation and analysis procedure. Sample data exhibiting
matrix effects will have been identified during the data verification/validation process.
Analytical accuracy/bias will be determined by evaluating the percent recovery data of LCSs. LCSs are
artificial samples prepared in the laboratory using a blank matrix fortified with target compounds from a
standard reference material that is independent of the calibration standards. LCSs are prepared and
analyzed in the same manner as the field samples. The percent recovery data from LCS analyses will
provide an indication of the accuracy and bias of the VOC analytical method.
Percent recovery is calculated using the following formula:
Percent Recovery = SSR - SR
SA x 100
where:
SSR = Spiked Sample Result
SR = Sample Result or Background
SA = Spike Added
Percent recovery for surrogate compounds and LCSs are determined by dividing the measured value by
the true value and multiplying by 100.
3.20.3 Sample Representativeness
Representativeness of the samples will be assessed by reviewing sample holding times and data from field
duplicate samples. Sample representativeness will be considered acceptable if holding time periods are
met and field duplicate RPD data are acceptable.
3.20.4 Completeness
Completeness will be assessed by comparing the number of valid (usable) sample results to the total
possible number of results within a specific sample matrix and/or analysis. Percent completeness will be
calculated using the following formula:
Percent Completeness = Number of Valid (Usable) Measurements
Number of Measurements Planned x 100
Completeness will be considered acceptable if 90 percent of the data are determined to be valid after
performance of the data validation procedures. Data qualified as estimated will be deemed usable.
EKI A70020.03 3-19 19 March 2018
3.20.5 Comparability
Comparability of data sets will be evaluated by reviewing the sampling and analysis methods used to
generate the data for each data set. Comparability will be determined to be acceptable if the sampling
and analysis methods specified in this Work Plan and any approved Work Plan revisions or amendments
are used for generating the data.
3.20.6 Sensitivity
Laboratory reports will adopt a method quantitation limit (i.e., reporting limit) that is equal to the
non-detection value of 0.5 µg/L for individual chlorinated VOCs specified in the Order (at 13 ¶ 49).
Sensitivity will be considered acceptable if the quantitation limit for the samples is sufficient to achieve
the detectability requirements for the investigation.
Quantitation limits may be elevated as a result of high concentrations of target compounds, non-target
compounds, and matrix interferences (collectively known as sample matrix effects). In these cases, the
sensitivity of the analyses will be evaluated on an individual sample basis relative to the applicable
evaluation criteria. The need to investigate the use of alternate analytical methods may be required if the
sensitivity of the analytical methods identified in this Work Plan cannot achieve the evaluation criteria as
a result of sample matrix effects.
EKI A70020.03 4-1 19 March 2018
4. GROUNDWATER INVESTIGATION SCHEDULE
As specified in Paragraph 2.2 of the Order, the Working Parties will implement the groundwater
investigation for determining the lateral and vertical extent of VOCs in groundwater originating from the
Site within 30 days of Work Plan acceptance by Water Board staff. The Working Parities will notify Water
Board staff at least 3 working days before implementing the investigation.
Consistent with Paragraph 2.3 of the Order, every 6 months after initiating implementation of the
groundwater investigation until all phases of the investigation are completed, the Working Parties will
submit technical reports to the Water Board summarizing the groundwater investigation activities
conducted during the prior 6 months in accordance with the accepted Work Plan. The technical reports
will include the information specified in Paragraphs 2.3.1 through 2.3.7 of the Order, presented below.
• A narrative description of work performed and information obtained.
• Boring logs and analytical data.
• Site map(s) showing the location of all borings (i.e. soil sampling points and depth discrete
groundwater sampling points) and Site monitoring wells. All figures will be drawn to scale, be in
color, and label relevant features, such as roads, relevant property boundaries, etc. The site maps
will also show the location of all identified preferential pathways (e.g. fill within utility corridors)
and relevant municipal/private water supply wells.
• An iso-concentration map showing all sampling locations and data points with boundary lines of
chlorinated hydrocarbons in groundwater drawn to 0.5 µg/L. Question marks will indicate areas
where boundaries are unknown.
• Description of the geology encountered within the investigation area footprint. Include geologic
cross sections extending from the Site to the limits of groundwater sampling that show depth
discrete groundwater sampling results.
• Depth of first encountered groundwater at all points sampled. State whether perched zones were
encountered and the basis for this finding. Describe whether or not the contaminants are
following preferential pathways and the basis for that conclusion.
• Description and schedule of anticipated future work.
Once a CSM is sufficiently developed, it will be discussed in the technical reports as well. In addition to
required submittal of technical reports, the Working Parties will provide more frequent updates, as
warranted, to Water Board staff by email and telephone calls. We anticipate that such updates will be
undertaken to communicate the progress of field work and interim investigative findings, and to obtain
any input Water Board staff wish to offer regarding planned follow-on activities.
When the Working Parties believe the Order investigation requirements have been fulfilled, we will meet
with the Water Board to obtain staff concurrence and to initiate remedial action planning, as needed. In
EKI A70020.03 4-2 19 March 2018
accordance with Section 4 of the Order, within 90 days of the due date of the final investigation technical
report, the Working Parties will submit a Corrective Action Plan (“CAP”) or equivalent remedial planning
document to the Water Board to cleanup or abate contamination origination from the Site. The CAP will
evaluate at least three cost-effective remedial technologies, state the selection basis for the
recommended technology, and provide a schedule for implementation of the recommended alternative.
Path: X:\A70020\Maps\2017\09\Fig1_SiteLocationMap.mxd0 1,800 3,600
(Scale in Feet)
Notes1. All locations are approximate.
SourcesWorld Topographic Map basemap provided by ESRI's ArcGIS Online, obtained 27 February 2018.
Site Location Map
South Lake Tahoe, CAMarch 2018EKI A70020.03Figure 1
±
LTLW Site
Former Lake Tahoe Laundry Works Site1024 Lake Tahoe Boulevard