DERR-2025-004764

Cover Page
Site Characterization Work
Plan, Revision 3
The Other Side Village Phase 2
Approximately 1882 West Indiana Avenue
Salt Lake City, Salt Lake County, Utah
June 25, 2025 | Terracon Project No. 61257031
Prepared for:
The Other Side Academy and Salt Lake City Corporation
Salt Lake City, Utah
6952 South High Tech Dr. Ste. B
Midvale, Utah 84047
P [phone]
Terracon.com
Facilities | Environmental | Geotechnical | Materials i
June 25, 2025
The Other Side Academy
and
Salt Lake City Corporation Department of Sustainability
Attn: Mr. Tim Stay, The Other Side Academy
P: [phone]
E: [e-mail]
Ms. Catherine Wyffels, Salt Lake City Corporation
P: [phone]
E: [e-mail]
Re:Site Characterizaiton Work Plan, Revision 3
The Other Side Village, Phase 2
VCP Site C136
Approximately 1882 West Indiana Avenue, Salt Lake City, Utah
Terracon Project No. 61257031
Dear Mr. Stay and Ms. Wyffels,
Terracon Consultants, Inc. (Terracon) is pleased to submit this Site Characterization Work
Plan on behalf of The Other Side Academy and Salt Lake City Corporation designed to
characterize soil, groundwater, surface water, and soil gas at the above-referenced site. We
understand a Voluntary Cleanup Agreement has been signed for enrollment in the Utah
Division of Environmental Response and Remediation’s (DERRs) Voluntary Cleanup Program
(VCP) and the site is designated as Site C136.
Sincerely,
Terracon Consultants, Inc.
Jill Hernandez, P.E.Amy Austin
Project Manager Authorized Project Reviewer
Amy Austin
Facilities | Environmental | Geotechnical | Materials ii
Table Of Contents
1.0 Introduction .................................................................................. 1
1.1 Project Background ..................................................................................... 1
2.0 Site Characterization Strategy ......................................................... 1
2.1 Utility Clearance and Safety .......................................................................... 2
2.2 Soil Characterization Method ........................................................................ 2
2.3 North Ditch Surface Water Characterization .................................................... 4
2.4 Groundwater Investigation Method ................................................................ 4
2.5 Soil Gas Investigation .................................................................................. 5
2.6 Investigation Derived Wastes........................................................................ 6
3.0 Analytical Program ......................................................................... 6
4.0 Regulatory Screening Levels ............................................................ 6
5.0 Quality Assurance/Quality Control .................................................... 7
6.0 Report .......................................................................................... 7
7.0 Contingency Plan............................................................................ 8
Appendices
Appendix A Exhibit
Exhibit 1 TOSV Phase 2 Boundary
Exhibit 2 TOSV Phase 2 Sampling Plan
Appendix B Table
Table 1 Sampling and Analytical Program
Site Characterization Work Plan, Revision 3
TOSV Phase 2 | Salt Lake City, Utah
June 25, 2025 | Terracon Project No. 61257031
Facilities | Environmental | Geotechnical | Materials 1
1.0 Introduction
The site comprises approximately 29.4 acres, located at approximately 1882 West
Indiana Avenue, Salt Lake City, Utah (Exhibit 1; Appendix A). Salt Lake City Corporation
(SLCC) owns the property. The Other Side Academy (TOSA) is seeking to lease the
property from SLCC to develop the property as a tiny home development to serve the
city’s unsheltered population. This development will be referred to as The Other Side
Village (TOSV), Phase 2.
The site is enrolled in the Utah Division of Environmental Response and Remediation’s
(DERR’s) Voluntary Cleanup Program (VCP) and is designated by DERR as VCP Site
C136.
This Site Characterization Work Plan (Work Plan) is designed to conduct an evaluation of
site soil, groundwater, surface water, and soil gas for environmental impacts prior to
development. Additional site characterization is required after a review of the initial
characterization results to further define and delineate impacts identified in this
investigation. Further investigation may be warranted, depending on the results of the
site characterization
1.1 Project Background
The Site is included within the boundaries of the Redwood Road Dump CERCLA facility
(Facility ID UTD980961502). TOSA is currently in the process of completing
development of a Pilot Phase of TOSV on the 8-acre parcel adjoining this property to the
east. That property was also enrolled in DERRs VCP and is designated by DERR as VCP
Site C121. Phase 2 of the TOSV is proposed to encompass the approximately 29.4 acres
adjoining the Pilot Phase.
Previous investigations conducted on the Redwood Road Dump site and the Phase 1
development identified the potential for elevated concentrations of metals and polycyclic
aromatic hydrocarbons (PAHs) in soil, dissolved metals and per- and poly-fluoroalkyl
substances (PFAS) in groundwater, and elevated concentrations of chloroform and
methane in soil gas.
2.0 Site Characterization Strategy
Terracon has developed this Work Plan outlining the proposed approach to gather
sufficient information to characterize soil, groundwater, surface water, and soil gas at
the Site. The property boundaries of Phase 2 will be surveyed by TOSA and marked at
the Site.
Site Characterization Work Plan, Revision 3
TOSV Phase 2 | Salt Lake City, Utah
June 25, 2025 | Terracon Project No. 61257031
Facilities | Environmental | Geotechnical | Materials 2
Standard Operating Procedures (SOPs) to be followed during the implementation of the
site characterization field work are described in detail in the Quality Assurance Project
Plan (QAPP) (Terracon, May 5, 2025), which were approved for the Phase 1, and are
summarized in the following sections. Soil, fill material, and surface water sampling
equipment will be cleaned using an Alconox wash and potable water before beginning
the project and before collecting each soil sample. The samples will be placed in
laboratory-prepared containers, labeled, and soil, fill material, groundwater, and surface
water samples will be placed on ice in a cooler. The sample coolers and completed
chain-of-custody forms will be relinquished to the analytical laboratory for analysis on a
standard turnaround time.
The following sections outline our field investigation methods. Exhibit 2 (Appendix A)
shows the locations of proposed sampling points. Table 1 (Appendix B) presents the
sampling strategy, rationale, analytes, and analytical methods.
2.1 Utility Clearance and Safety
Following receipt of a notice to proceed and no later than 72 hours prior to intrusive
activities, the selected drilling and excavation subcontractors will contact the public
utility locating service (Blue Stakes) to arrange for underground utility locates at the
site. Terracon will also subcontract with a private utility locating service to clear the
sample locations.
Terracon has a 100% commitment to the safety of all its employees. As such, and in
accordance with our Incident and Injury Free® safety culture, Terracon will develop a
safety plan to be used by our personnel during field services. Prior to commencement of
on-site activities, Terracon will hold a meeting to review health and safety needs for this
specific project. At this time, we anticipate performing fieldwork in United States
Environmental Protection Agency (EPA) Level D work uniforms consisting of hard hats,
safety glasses, protective gloves, and steel-toed boots.
2.2 Soil Characterization Method
This Work Plan includes the evaluation of fill material, native soil, and the soil within the
North Ditch. It does not include surface soil samples as the development plan for the site
includes the removal of all non-native imported material prior to development.
Test pits/trenches will be excavated within one-acre sampling grids, similar to the
approximate initial sample spacing conducted within TOSV Phase 1, to evaluate the soil
profile and collect environmental samples. Soils from the test pits/trenches will be
logged to document general lithology, color, and the presence or absence of fill and
debris. The test pit/trench logs will define the type and depth of fill material, presence of
municipal waste and/or landfill debris, if present, and the native soil depth. Soils will be
Site Characterization Work Plan, Revision 3
TOSV Phase 2 | Salt Lake City, Utah
June 25, 2025 | Terracon Project No. 61257031
Facilities | Environmental | Geotechnical | Materials 3
field screened using a photoionization detector (PID) to qualitatively evaluate the
presence of volatile organic compounds (VOCs).
Excavated materials will be placed back into the excavation in the approximate order it
was removed. No debris or suspect contaminated materials will be left on the surface of
the site after excavation.
2.2.1 Characterization of Fill Material
One soil sample will be collected from each test pit/trench within the observed fill
material. The sample to be submitted for VOC analysis will be a grab sample from the
6-inch interval with the greatest impacts, such as elevated PID readings and/or staining.
If evidence of impacts is not observed, the grab sample will be collected from a 6-inch
interval in the approximate center of the vertical profile. Samples analyzed for non-
volatile analytes, such as metals, SVOCs, PAHs, and polychlorinated biphenyls (PCBs),
will be composited from the material encountered from the surface to the total depth of
the observed fill material using a hand trowel for soil sample collection.
Materials excavated from the test pits will be examined for the presence of potential
Asbestos-Containing Building Materials (ACBM) by a Certified Asbestos Building
Inspector, as required by the Utah Division of Air Quality rules (UAC R307-801). If
suspect materials are observed, a sample will be collected of each material type to
assess the asbestos content.
2.2.2 Characterization of Native Soil
One soil sample will be collected from each test pit/trench from the observed native soil
profile, below observed fill material. The grab soil sample will be collected from the top 6
inches to 1 foot of the native soil interval.
2.2.3 North Ditch Soil Characterization
The location of the North Ditch alignment through the property will be mapped. Surface
soil samples will be collected along the North Ditch to characterize potential impacts in
soils within the ditch. A total of three soil samples will be collected from the shallow
soil/sediments in the North Ditch within the site boundary. Shallow soil samples will be
collected from the sediments/surficial soils from 0 to 4 inches below the surface using a
hand trowel.
2.2.4 Characterization of Hummocks and Stockpiles
Hummocks, mounds of debris, and stockpiles were observed throughout the site. The
contents of the hummocks, mounds and stockpiles will be evaluated using a backhoe
and visually observed for the contents. The contents of the hummock/stockpile will be
Site Characterization Work Plan, Revision 3
TOSV Phase 2 | Salt Lake City, Utah
June 25, 2025 | Terracon Project No. 61257031
Facilities | Environmental | Geotechnical | Materials 4
logged. Up to 10 hummocks/stockpiles will be selected during the site walk to be
evaluated for the content. Up to 5 samples may be collected from hummocks and/or
stockpiles at the discretion of the field technician and the Terracon and DERR Project
Managers for any material deemed suspect of impacts.
2.2.5 Leachate Sample Collection
If leachate or other suspect sheen or discoloring is observed in groundwater during the
excavation of test pits, a sample of the leachate will be collected from the test pit using
a disposable bailer or remote sampling device.
2.2.6 Opportunity Samples
This Work Plan provides an opportunity to collect up to five samples from any suspect fill
material or soil in the test pits/trenches, hummocks, or other features of potential
environmental concern observed at the site. The samples may be collected at the
discretion of the field technician and the Terracon and DERR Project Managers for any
material deemed suspect of impacts and not covered under any other sampling protocol.
The samples will be collected as described for the characterization of fill material in
Section 2.2.1, unless other analyses appear appropriate, such as for ACBM, petroleum
staining, suspect materials, etc. The analytical methods may be adjusted, if regulatory
approval is received, based on item or feature encountered and the anticipated impacts.
2.3 North Ditch Surface Water Characterization
Surface water samples will be collected from North Ditch, if sufficient surface water is
present during the investigation to collect a sample, to characterize potential impacts in
surface water within the ditch. A total of two surface water samples will be collected
from the northwest and southeast portions of North Ditch within the site boundary.
Surface water samples will be collected from the using a decontaminated remote
sampling device with a collection cup attached to a pole. Samples for analysis of metals
will be filtered through an in-line, disposable, 0.45-micron pore filter.
2.4 Groundwater Investigation Method
Groundwater conditions will be evaluated through the installation of six temporary
monitoring wells installed on the site. Permanent monitoring wells will not be installed as
the site will be significantly redeveloped. These temporary wells will be used to evaluate
potential groundwater impacts and develop a remedial action plan. The monitoring wells
will be surveyed, and water level measurements will be collected to calculate the
direction of groundwater flow in the shallow groundwater aquifer.
Site Characterization Work Plan, Revision 3
TOSV Phase 2 | Salt Lake City, Utah
June 25, 2025 | Terracon Project No. 61257031
Facilities | Environmental | Geotechnical | Materials 5
Soil borings for the temporary groundwater monitoring points will be advanced with
direct push (“Geoprobe”)drilling equipment outfitted with 3.75-inch rods to allow for the
installation of 1.5-inch pre-packed well screens. The mechanized drilling services will be
performed by a Utah-licensed well driller. Terracon environmental personnel will select
the boring locations and visually observe the drilling activities, but soils will not be
logged or sampled.
2.4.1 Monitoring Well Development
The temporary groundwater sampling wells will be developed using a peristaltic pump.
Approximately five well casing volumes of water will be removed from each well prior to
sampling.
2.4.2 Groundwater Sample Collection
Groundwater samples will be collected from each groundwater sampling point using low-
flow sampling methods as described in the QAPP (SOP E 1940). In general, the wells will
be purged using a low-flow peristaltic pump with the inlet placed within the top foot of
the water column. The peristaltic pump will be set to pump water at a rate of 200
milliliters per minute (mL/min) or less. The wells will be purged until groundwater
quality parameters of pH, temperature, conductivity, dissolved oxygen, and turbidity
stabilize to within 10% over three consecutive readings.
In some cases, it may not be possible to achieve stabilization of the water quality
parameters. In those cases, the well will be purged until either three casing volumes are
removed or the well pumps dry. If the well purges dry before water quality parameters
stabilize, the well will be allowed to recharge, and a sample will be directly collected
from the well using the low-flow method.
Once the sampling criteria has been met, the sample will be collected while the well
purging pump is still in place. The laboratory-supplied sample containers will be filled out
of the pump discharge line maintaining the low-flow setting.
Samples collected for analysis of PFAS compounds require special handling procedures,
as detailed in SOP 12 included in the QAPP. In general, Terracon will employ the “Clean
Hands—Dirty Hands” protocol, developed by the EPA for sampling low level metals and
can be used for other contaminants that are analyzed in the parts per trillion range.
Samples for analysis of metals will be filtered through an in-line, disposable, 0.45-
micron pore filter.
2.5 Soil Gas Investigation
To evaluate soil gas, nine soil gas sampling points will be installed using direct-push
drilling equipment to advance a boring to an approximate depth up to 5 feet below
Site Characterization Work Plan, Revision 3
TOSV Phase 2 | Salt Lake City, Utah
June 25, 2025 | Terracon Project No. 61257031
Facilities | Environmental | Geotechnical | Materials 6
ground surface (bgs) for installation of the sampling point probes. The sampling point
probes will consist of a 6-inch long stainless steel disposable screen anchored to Teflon®
tubing that extended to the surface. A one-foot 10–20 silica sand pack will be placed
around the probe and the remainder of the anulus will be filled with hydrated bentonite
chips. Care will be taken to ensure adequate hydration of the chips to avoid air flow
through the bentonite which might dilute the soil gas sample.
The soil gas probes will be allowed to equilibrate for a minimum of 20 hours before
sampling. Prior to sample collection, Terracon will conduct leak detection tests at the
sample locations.
After sample collection, the soil gas probes will be capped and remain in the ground for
future sampling events.
2.6 Investigation Derived Wastes
Soils excavated from the test pits/trenches will be returned to the pit from which they
were removed. Groundwater from well development and sampling and surface water
from North Ditch sampling will be thin spread in the vicinity of the sampled well or ditch
sampling location.
3.0 Analytical Program
The samples will be submitted to a Utah-certified laboratory for analysis. Table 1
(Appendix B) presents the proposed sample analyses for this site characterization event.
4.0 Regulatory Screening Levels
The laboratory analytical results will be compared to current Environmental Protection
Agency (EPA) regulatory guidance and standards. Soil sample results will be compared
to EPA Regional Screening Levels (RSLs) for residential and industrial use scenarios.
Groundwater sample results will be compared to the EPA Federal Maximum Contaminant
Levels (MCLs) for drinking water and the EPA Vapor Intrusion Screening Level (VISL)
Target Groundwater Concentrations (TGC). Soil gas samples will be compared to the US
EPA VISLs. If an MCL is not established for an analyte, the results will be screened
against the US EPA RSL for tapwater.
Methane is a common product of decomposition of organic matter at landfill sites. The
EPA has not established a VISL for methane, but a general industry practice is to use an
Action Level of 5 percent of methane’s Lower Explosive Limit (LEL). The LEL represents
the lowest concentration of methane in air that can ignite or explode when an ignition
source is present. The LEL for methane is 5 percent, which is equivalent to 50,000 parts
Site Characterization Work Plan, Revision 3
TOSV Phase 2 | Salt Lake City, Utah
June 25, 2025 | Terracon Project No. 61257031
Facilities | Environmental | Geotechnical | Materials 7
per million by volume (ppmv); therefore, the methane Action Level will be considered as
5 percent of 50,000 ppmv (2,500 ppmv).
5.0 Quality Assurance/Quality Control
The sample analyses will be conducted by Pace Analytical Laboratories under a QC
Program, which includes the final analytical report with qualifiers where necessary; case
narratives, chain-of-custody records; and results for method blanks, a matrix spike and
matrix spike duplicate analyses with control limits; laboratory control sample and
laboratory control sample duplicate summary with control limits; reporting limits listed
on all reports; and surrogate recoveries..
Field duplicates will be selected at random and collected at a rate of 10 percent of soil
and groundwater samples.
Trip blank samples will be collected at a rate of 10 percent for groundwater samples,
which are analyzed for VOCs and PFAS. One field blank sample will be collected and
included in the sample transport for groundwater samples analyzed for PFAS.
Soil boring logs, groundwater sample forms, and field notes will be completed during the
field work. The work will be conducted following Terracon’s Standard Operating
Procedures, which were included in the QAPP.
Site-specific conditions may require an adjustment to the field program and a deviation
from this Work Plan to accommodate site-specific needs. If an adjustment or deviation
becomes necessary, the activities and reasoning will be documented and implemented.
Such adjustments (for example, adjustments in sampling locations) may introduce some
degree of variability, which will be reconciled with project information by evaluating
whether contaminant levels may be underestimated or overestimated, and how this may
affect eventual site management or cleanup approaches, if applicable.
6.0 Report
A report will be prepared and submitted within 30 days of receipt of laboratory analytical
data. Following the validation of field and laboratory data, the data and information will
be reconciled with the project objectives to assess the overall success of sampling
activities. The report will include, at a minimum, site observations (e.g., subsurface
lithology, distribution of impacts, boring and test pit logs) comprehensive analytical
results and QA/QC tables, deviations from this Work Plan, and sample location maps.
Site map development will include mapping of likely boundaries and thickness of
municipal waste originating from the former Redwood Road landfill and general debris.
Site Characterization Work Plan, Revision 3
TOSV Phase 2 | Salt Lake City, Utah
June 25, 2025 | Terracon Project No. 61257031
Facilities | Environmental | Geotechnical | Materials 8
7.0 Contingency Plan
If unidentified environmental concerns are encountered during the site investigation,
work will stop in the area of the concern until TOSA, SLCC, DERR and Terracon can
determine an appropriate course of action.
Appendix A
Exhibits
DraftDraft
G:
\
0
0
6
1
\
6
1
2
1
7
2
5
5
_
T
O
S
A
\
6
1
2
1
7
2
5
5
_
T
O
S
A
.
a
p
r
x
Exhibit
terracon.comPH. 801-545-8500
6952 S High Tech Dr, Ste B
Midvale, UT
Reviewed By:
Drawn By:
Jun 2025
Date:
61257031
Project No.:
Approximately 1882 West Indiana Avenue
Salt Lake City, Utah
TOSV Phase 2 Sampling Plan
2
NMS
AST
215
Indiana Ave
22
Indiana Ave I n d i a n a A v e
0 300 600150
Feet
Proposed Temporary Monitoring
Well
Proposed Soil Sample
Proposed Surface Water Sample
Proposed 2025 Soil Gas Sample
Location
Proposed 2025 Test Pit
Sewer Line with 30-Foot Buffer
High Energy Gas Line
Approximate Underground
Water Line
Approximate North Ditch
Alignment
Sample Grid
Phase I VCP Site Boundary
Phase 2 Boundary
Appendix B
Table
Sample/Field ID Type and
Designation
Purpose
REC/Site Concern
Collection
Method Sample Type Target Interval/Depth Analytical1
Characterize fill material
and depth of fill
Grab (VOCs) or
Composite (Non-VOCs)
of observed fill profile
Fill Material
VOCs, RCRA Metals,
SVOCs, PAHs, PCBs,
ACBM if suspect material
observed
Characterize native soil
directly beneath fill material
Grab sample of native
soil within
6-inches to 1 foot below
fill
Native Soil VOCs, RCRA Metals,
SVOCs, PAHs, PCBs
SP-1 to SP-10
Characterization of the
contents of
hummocks/stockpiles
TBD in field with
agency
Up to 5 opportunity
samples to characterize
locations or items of
potential environmental
concern
Grab (VOCs) or
Composite (Non-VOCs)
of observed fill profile
or other item/feature of
concern
Appropriate Depth
Based on Field
Observations and
Item/Feature
Encountered
VOCs, RCRA Metals,
SVOCs, PAHs, PCBs,
ACBM if suspect material
observed2
Opportunity Test Pits
TP-31 to TP-35
TBD in field with
agency
Opportunity samples to
characterize locations or
items of potential
environmental concern
Grab (VOCs) or
Composite (Non-VOCs)
of observed fill profile
or other item/feature of
concern
Fill Material or Other
Appropriate Depth
Based on Field
Observations and
Item/Feature
Encountered
VOCs, RCRA Metals,
SVOCs, PAHs, PCBs,
ACBM if suspect material
observed2
ND-1 to ND-3 Surface Soil Evaluate soils and
sediments in North Ditch Hand Trowel Composite 0-4 inches VOCs, RCRA Metals,
SVOCs
NDSW-1 to NDSW-2 Surface Water Evaluate surface water in
North Ditch, if present
Remote Sampling
Device Surface Water Within Surface Water
Depth
VOCs, RCRA Metals*
hexavalent chromium*,
1,4-dioxane, SVOCs,
pesticides, PFAS
Leachate Opportunity
Samples Water
Evaluate of suspect
water/leachate
encountered in test
pits/subgrade excavation
Remote Sampling
Device Water/Leachate TBD in field VOCs, RCRA Metals*
hexavalent chromium*
Table 1 - Sampling and Analytical Program
The Other Side Village - Phase 2
Approximately 1882 West Indiana Ave, Salt Lake City, Utah
Terracon Project No. 61257031
Soil Characterization
North Ditch
TP-1 to TP-30
ExcavatorTest Pit/Trench
Leachate
Page 1 of 2
Draft
Sample/Field ID Type and
Designation
Purpose
REC/Site Concern
Collection
Method Sample Type Target Interval/Depth Analytical1
Table 1 - Sampling and Analytical Program
The Other Side Village - Phase 2
Approximately 1882 West Indiana Ave, Salt Lake City, Utah
Terracon Project No. 61257031
SG-1 to SG-9 Soil Gas Evaluate soil gas Geoprobe - Soil
Gas Probe Soil Gas between
3 to 5 feet bgs VOCs, Methane
TGP-1 to TGP-6 Groundwater Evaluate current
groundwater conditions
1.5" Pre-packed
PVC Screen Groundwater up to 15 feet bgs
VOCs, RCRA Metals*
hexavalent chromium*,
1,4-dioxane, SVOCs,
pesticides, PFAS, TDS
Notes:TP-Test Pit. ND-North Ditch. NDSW - North Ditch Surface Water. SG-Soil Gas. TGP - Temporary Groundwater Point.TBD - To be determined.
1Analytical Methods:
ACBM - Asbestos-containing building materials by EPA Method 600/R-93/116
PAHs by EPA Method 8270 SIM; PCBs - Polychlorinated Biphenyls by EPA Method 8082; PFAS - Per- and poly-fluoroalkyl substances by EPA Method 1633
RCRA Metals - Arsenic, Barium, Cadmium, Chromium, Lead, Mercury, Selenium, and Silver by EPA Method 6000 and 7000 series, *Dissolved
SVOCs - Semi-volatile Aromatic Hydrocarbons by EPA Method 8270; 1,4 Dioxane by EPA Method 8260 SIM
TDS-Total dissolved solids by EPA SM 2540 C; VOCs - Volatile organic compounds by EPA Method 8260 (soil and groundwater) and TO-15 (soil gas)
2Analytical methods may be adjusted with regulatory approval based on item or feature encountered.
bgs - below ground surface
Groundwater Assessment
Soil Gas
Page 2 of 2
Draft