DSHW-2024-008068

WASATCH ENVIRONMENTAL, INC.
ENVIRONMENTAL SCIENCE AND ENGINEERING
AMENDED SITE MANAGEMENT PLAN
FORMER GSA MOTOR POOLPROPERTY
330 EAST 200 SOUTH
SALT LAKE CITY, UTAH
Project No. 2201-001G
To:
Mr. Douglas Hansen, Director
Utah Department of Environmental Quality
Division of Waste Management and Radiation Control
195 North 1950 West, 2nd Floor
P.O. Box 144880
Salt Lake City, Utah 84114-4880
Prepared For:
Mr. Ryan Heath
Cottonwood Residential O.P., LP
6340 South 3000 East, Suite 500
Cottonwood Heights, Utah 84121
Prepared By:
Wasatch Environmental, Inc.
2410 West California Avenue
Salt Lake City, Utah 84104
July 26, 2019
Revised August 23, 2024
2410 WEST CALIFORNIA AVENUE
SALT LAKE CITY, UTAH 84104
PHONE [phone]
FAX [phone]
e-mail: [e-mail]
www.wasatch-environmental.com
TABLE OF CONTENTS
Section Page No.
1.INTRODUCTION 1
1.1 Site Description 1
1.2 Site Background 1
2.RISK ASSESSMENT 3
3.SITE MANAGEMENT 3
3.1 Activity and Use Limitations 3
3.1.1 Site Management Plan 4
3.1.2 Land Use Limitations 4
3.1.3 Groundwater Limitations 4
3.1.4 Disturbance Limitations 4
3.1.5 Construction Dewatering Limitation 4
3.1.6 Vapor Intrusion Limitations 4
3.1.7 Groundwater Monitoring Requirements 4
3.1.8 Indoor Air Monitoring Requirements 4
4.CONSTRUCTION MANAGEMENT 4
4.1 Discovery of Unknown Contamination During Construction 4
4.2 Management of Groundwater During Construction 4
4.3 Construction Worker Health and Safety 4
5.MAINTENANCE, ACCESS AND INSPECTIONS 4
5.1 Notice 5
5.2 Disruption 5
5.3 Environmental Covenant 5
6.SITE MANAGEMENT CONTACTS 5
Figures
Figure 1 – Property Location Map
Figure 2 – Parcel Map
Figure 3 – Site Map
Appendices
Appendix A – Amended Environmental Covenant
Wasatch Environmental, Inc.Table of Contents
Page i
Page 3
AMENDED SITE MANAGEMENT PLAN
FORMER GSA MOTOR POOL PROPERTY
330 EAST 200 SOUTH
SALT LAKE CITY, UTAH
1.INTRODUCTION
Wasatch Environmental, Inc. (Wasatch), prepared a Site Management Plan, dated July 26, 2019, and
later revised on August 12, 2019 (SMP) to present the planned long-term approach for managing
chlorinated solvent impacts to groundwater at the Former GSA Motor Pool facility (Property). Based on
the results of subsequent groundwater sampling and indoor air monitoring at the Property, and with the
consent of the Utah Department of Environmental Quality (UDEQ), Division of Waste Management and
Radiation Control (DWMRC), Wasatch has prepared this amended SMP which revises various of the
Activity and Use Limitations and other requirements as reflected below (Amended SMP).
The SMP and this Amended SMP have been prepared in accordance with the requirements of R315-
101 “Cleanup Action and Risk-Based Closure Standards” that establishes information requirements to
support risk-based cleanup and closure standards at facilities for which remediation or removal of
hazardous constituents to background levels is not expected to be achieved. Except as set forth in the
Amended Environmental Covenant (Amended EC) recorded with the Salt Lake County Recorder’s
Office, the property owner and the Amended EC “Holder” (as defined in the Amended EC) shall comply
with this Amended SMP. Provisions of the Amended SMP relating to the land use limitations, however,
shall be the responsibility of the “Owner” (as defined in the Amended EC) of the Property.
The Owner shall notify DWMRC within 20 days after each transfer of ownership of all or any portion of
the Property. The Owner’s notice to DWMRC shall include the name, address and telephone number of
the transferee, a copy of the deed or other documentation evidencing the transfer, and an unsurveyed
plat that shows the boundaries of the property being transferred.
The original EC was recorded by the General Services Administration (GSA), but the Property was
shortly thereafter purchased by Cottonwood Residential O.P., LP (Cottonwood Residential), who has
redeveloped the Property with an underground parking structure and residential apartments above the
parking structure. The Amended EC was recorded by Cottonwood Residential.
1.1 Site Description
The Property is 1.54 acres in size and consists of one parcel (parcel number: 16-06-252-01) located at
330 East 200 South in Salt Lake City, Utah. The entire Property is included in the restrictions described
below, as detailed therein. The legal description obtained from the Salt Lake County Assessor’s website
is presented below.
Beginning at the Northeast corner of Lot 6, Block 49, Plat “B”, Salt Lake City Survey, and running thence
South 20 rods; thence West 4 rods; thence South 10 rods; thence West 39.0 feet; thence South 166.4
feet to the North line of Third South Street; thence West 60.0 feet, thence North 385.4 feet; thence East
50.0 feet; thence North 34.31 feet; thence East 6.0 feet; thence North 39.03 feet; thence West 6.0 feet;
thence North 202.66 feet; thence East 115 feet to place of beginning.
The Property is accessed by 200 South along the northern boundary and 300 South along the southern
boundary.
A Property Location Map, a Parcel Map, and a Site Map are presented as Figures 1, 2 and 3,
respectively.
1.2 Site Background
Our research indicates the Property was originally occupied by residential, church, and school structures
from at least 1889 through the 1940s. Residences remained on the Property until at least 1962. GSA
Page 4
purchased the majority of the Property in 1965 and constructed the northern portion of the GSA
maintenance building in 1966. A southern addition to the GSA building was constructed in 1982. GSA
used the Property as a fueling location for the Federal Bureau of Investigations (FBI) fleet vehicles and as
an automotive service facility.
The GSA Motor Pool was a Federal Government Motor Pool, which performed vehicle maintenance and
supplied fuel. The site had seven hydraulic lifts, two oil water separators, trench drains, two underground
storage tanks (USTs), both initially used for the storage of fuel, however, one was used as a waste oil
tank during later years of operation at the facility.
In November and December 2016, Wasatch conducted subsurface investigation activities which included
the collection of numerous surficial soil, subsurface soil, and groundwater samples at the Property in
areas of potential concern or features of interest, as noted by Hao Zhu, P.E., DWMRC. Soil and
groundwater samples were analyzed for volatile organic compounds (VOC), semi- volatile organic
compounds (SVOC), polynuclear aromatic hydrocarbons (PAH), and Total Petroleum Hydrocarbons
(TPH).
After the soil removal action was completed in October 2017 and February 2018, soil analytical results
indicated no areas of soil impacts remained above the United States Environmental Protection Agency
(U.S. EPA) Regional Screening Levels (RSL) for residential soils.
VOCs, specifically PCE, trichloroethene (TCE), and cis-1,2 dichloroethene (cis-1,2-DCE), were detected
in groundwater samples at concentrations that exceed their Federal Maximum Contaminant Levels
(MCLs); however, it is Wasatch’s opinion that the elevated groundwater concentrations of these
compounds at the Property are likely representative of VOC concentrations in groundwater which are due
to an upgradient off-site, adjacent former dry cleaning facility and not the result of GSA activities at the
Property. DWMRC concurred with this conclusion and issued the current owner a “Comfort Letter” dated
January 27, 2017.1
During February 2018, the GSA, at the request of UDEQ, began the process to excavate and remove the
facility subsurface equipment, hydraulic lifts, waste management apparatus, oil water separators and
trench drains, and storage tanks and ancillary equipment (USTs and fuel island pad locations) and limited
amounts of soil, and then sampled the soil from the associated excavation. Most of the soil from each of
the excavations was sampled and screened for VOCs with a photoionization detector (PID). Soil samples
were analyzed for total petroleum hydrocarbons as diesel range organics (TPH-DRO), VOCs which
included total petroleum hydrocarbons as gasoline range organics (TPH-GRO), SVOCs, and PAHs. Soil
from the hoist location was analyzed slightly differently with N-Hexane Extractable Material (HEM or
O&G), metals, and VOCs to primarily be used for waste characterization.
During this process, only two features, the two former fuel island pad locations, showed signs of soil
contamination (staining and/or odor). Though both of these exhibited positive VOC measurements on the
PID, only the northern location had significant odor and staining. From the two former fuel island location
excavations, GSA removed and disposed over 600 tons of primarily TPH contaminated soil.
Since the primary source of visible contamination was from a former fuel island pad, GSA and Wasatch
contacted the UDEQ leaking underground storage tank (LUST) program to ensure the Property would be
closed under this program as well. Though there were detections of PAHs, TPH-DRO, VOCs (primarily
TPH-GRO, PCE, and methyl tertiary butyl ether (MTBE)) for soils which remain on-site, all but the MTBE
were below either the LUST Program Initial Screening Level (ISL) or U.S. EPA RSLs for residential soils.
MTBE has been analyzed in soil and groundwater with over 100 samples and has only one detection
(0.35 mg/kg) which exceeds the ISL of 0.3 mg/kg. GSA received a No Further Action letter dated July 10,
2018 from the Utah Division of Environmental Remediation and Response, for the petroleum hydrocarbon
release associated with the past GSA operations. The SMP and this Amended SMP address PCE related
contamination.
1 That upgradient, adjacent former dry cleaning facility has completed remediation, and on January 23, 2024, DWMRC
issued a Corrective Action Complete with Controls Approval for that facility.
Page 5
2.RISK ASSESSMENT
No formal human health risk assessment or ecological risk assessment has been performed for the
Property. However, the US EPA Vapor Intrusion Screening Level (VISL) calculator was used in
assessing the potential vapor intrusion risk at site as a result of the presence of volatile organic
compounds (VOCs) detected in groundwater at the site.
Detected VOCs at the site consisted of the chlorinated solvents (PCE, TCE, cis-1,2-DCE and vinyl
chloride). Concentrations of VOCs in groundwater at some monitoring well locations exceeded the
U.S.EPA MCLs as well as the groundwater VISL values for both residential and commercial/industrial
dwelling.
PCE concentration in monitoring wells ranged from 1,000 micrograms per liter (ug/L) in MW-3 to <2.00
ug/L in monitoring wells MW-6 and MW-7. Monitoring well MW-3 is located along the eastern boundary of
the property and is hydraulically down-gradient from the former dry-cleaning facility which was located on
the adjoining east property.
Using the maximum detected PCE and TCE concentrations of 1000 ug/l and 23.0 ug/l respectively in
MW-3 as input into the VISL calculator indicates an indoor air PCE concentration of 724 ug/m3 and TCE
indoor air concentration of 9.26 ug/m3. The cumulative inhalation cancer risk under residential dwelling,
due to the presence of the two VOCs indoor, is 8.6x10-5. The Hazard Index for PCE indoor air non
carcinogenic risk in MW-3 was 22. Since this value is greater than one, corrective action or the use of
post-construction site specific data to calculate indoor air concentrations and resulting inhalation risk
was to be conducted.
Maximum TCE concentration in MW-5 was 120 ug/l, while MW-1, MW-6, and MW-7 reported
concentrations less than 2.0 ug/l. MW-5 is located hydraulically down-gradient of MW-3. Maximum PCE
concentration in MW-5 was reported at 526 ug/l. At these concentrations, calculated indoor TCE
concentration was 48.3 ug/m3 and PCE indoor concentration was 381ug/m3.
The cumulative residential inhalation cancer risk due to the presence of PCE and TCE in indoor air was
calculated to be 1.4x10-4. MW-5 is the only well on site with VOC concentrations exceeding indoor
inhalation cancer risk of 1x10-4. The Hazard Index for PCE indoor air non carcinogenic risk from MW-5
was 32. Since this value is greater than one, corrective action or additional assessment of vapor intrusion
pathway, including the use of post-construction site specific data to calculate indoor air concentrations
and resulting risk was to be conducted.
The Hazard Index for Commercial land use indoor air for PCE and TCE in MW-3 was 5 and for MW-5 was
approximately 8. Since these values are greater than one, corrective action or further assessment of
vapor intrusion pathway, including the use of post-construction site specific data to calculate indoor air
concentrations and resulting risk was to be conducted. On April 12-13, 2023, Wasatch collected indoor air
quality data for PCE, TCE and other daughter products prior to leasing office occupancy to demonstrate
that the vapor mitigation system installed is working as designed. Although the leasing office is
commercial space, the samples were collected for 24-hours and compared to EPA Regional Screening
Levels (RSLs) for residential use. The results were below laboratory method detection limits for five of the
six samples, and the results for the remaining sample contained a trace concentration of PCE well below
the RSL for indoor air at residential sites, indicating that there is not a vapor intrusion concern for indoor
air quality and that the vapor mitigation system is functioning as designed. Based on these results, the
leasing office area qualifies for residential or commercial/industrial land use provided that the vapor
barriers are maintained.
3.SITE MANAGEMENT
3.1 Activity and Use Limitations
The Amended EC recorded against the Property imposes the following activity and use limitations on the
Restricted Property:
Page 6
3.1.1 Site Management Plan
The Owner shall comply with this Amended SMP.
3.1.2 Land Use Limitations
The Property is suitable for residential, commercial and industrial use consistent with applicable
local zoning laws; provided that residential land use and land use involving sensitive populations
is restricted to areas located above the parking structure, or an active or passive vapor mitigation
system (unless the Director approves an alternative method that adequately mitigates vapor
intrusion risk). Planting crops or fruit trees for consumption by humans or livestock is prohibited.
3.1.3 Groundwater Limitations
Groundwater from the shallow unconfined aquifer shall not be used for drinking water, irrigation,
or bathing purposes. Other uses of groundwater from the shallow unconfined aquifer on the
Restricted Property shall be subject to review and approval by the Director prior to
implementation.
3.1.4 Disturbance Limitations
Appropriate care shall be exercised during remodeling, and maintenance activities related to
human-occupied structures in direct contact with site soils (not above the parking structure) as
to prevent damage to any installed vapor mitigation measures which have been installed, and
to ensure appropriate repairs are promptly made in the event that damage does occur.
If activities are undertaken that access or disturb soils or groundwater under the Property,
onsite workers and/or construction workers may be exposed to VOC contaminated soil or
groundwater at the Property. The Property Owner shall ensure that steps are taken to prevent
worker exposure to contamination. This includes any dewatering of the aquifer. Management
and disposal of impacted media from the Property must be consistent with all pertinent federal
and state environmental laws.
3.1.5 Vapor Intrusion Limitations
The Director has approved engineering controls consisting of an underground parking
structure which is open to the atmosphere and properly ventilated, and a vapor barrier system
in areas which are constructed directly above site soil. The April 2023 indoor air vapor
sampling data has confirmed that Cottonwood’s vapor mitigation system is working effectively.
For enclosed structures intended for human occupancy on the ground floor (whether commercial
or residential), vapor intrusion mitigation measures are required to be maintained to mitigate
exposure risks from the vapor intrusion pathway. Changes to the vapor mitigation measures shall
be subject to review and approval by the Director prior to implementation.

4.MAINTENANCE, ACCESS AND INSPECTIONS
Under the Amended EC, the Owner of any portion of the Property, shall be responsible for the
continued maintenance of any engineering controls implemented under this Amended SMP and the
Amended EC, on the portion of the Property which it owns.
The property owner under the Amended EC and the Director of the DWMRC (Director) and their
respective authorized agents, employees, and contractors shall have rights of reasonable access to the
Property at any time after the effective date of the Amended EC for inspections and monitoring of the
compliance with the Amended EC, and for complying with the terms and conditions of the Amended EC
and this Amended SMP. Nothing in this Amended SMP shall be construed as expanding or limiting any
access and inspection authorities of the DWMRC and Director under the law.
Page 7
4.1 Notice
Any party or person desiring to access the Property under authority of the Amended EC shall provide
notice to the then current Owner of the affected portion of the Property not less than 48 hours in advance
of accessing the Property, except in the event of an emergency condition which reasonably requires
immediate access. In the event of any such emergency condition, the party exercising this access right
will provide notice to the then current owner of the affected portion of the Property as soon thereafter as
is reasonably possible. The DWMRC, the Director, and their authorized officers, employees, or
representatives may, at any reasonable time and upon presentation of appropriate credentials, have
reasonable access to the Property.
4.2 Disruption
To the extent that the owner, the Director or their authorized representatives, conduct any activities on or
within any portion of the Property, they will use reasonable efforts to comply with the then current Owner’s
security needs and requirements, and will conduct such activities so as to cause the least amount of
disruption to the use of the affected portion of the Property as may be reasonably possible. Any person
who conducts any activities shall repair or replace any improvements damaged on the affected portion of
the Property by such activities.
4.3 Environmental Covenant
An Amended EC containing the above referenced institutional controls, was filed for recording in the
same manner as a deed to the property, with the Salt Lake County Recorder’s Office. A copy of the
recorded Amended EC is attached as Appendix A.
5.SITE MANAGEMENT CONTACTS
Inquiries concerning the Amended SMP should be directed to the following:
Cottonwood Residential O.P., LP
1245 Brickyard Rd, Suite 250
Salt Lake City, Utah 84106 (801)
278-0700
And
Utah Department of Environmental Quality
Director - Division of Waste Management and Radiation Control
P.O. Box 144880
Salt Lake City, Utah 84114-4880
[phone]
Page 8
Approximate
Location of
Subject Property
Property Location Map Figure 1
Page 9
16-06-252-001
16-06-251-007
16
-
0
6
-
2
5
2
-
0
0
8
Approximate
Location of
Subject Property
Parcel Map Figure 2
Page 10
Approximate
Location of
Subject Property
Former
Big Lots
) E 200 S(370
200 South
Liberty Midtown
Apartments
) S 300 E(225
Fres
h
Life
C
h
u
r
c
h
(320
E 2
0
0

S
)
Salt Lake City
Public
Safety Building
(321 E 200 S)
Vacant Twilite
Lounge
) E 200 S(347
E
a
s
t
40
0
E
a
s
t
30
0
300 South/Broadway
Ox
f
o
r
d

P
l
a
c
e

Ap
a
r
t
m
e
n
t
s
(3
3
5
)
E

3
0
0

S
Me
t
r
o

N
a
t
i
o
n
a
l

T
it
l
e
B
r
o
a
d
w
a
y
(3
4
5
)
Lol
i
e

E
c
c
l
e
s

E
a
r
l
y
Edu
c
a
t
i
o
n

C
e
n
t
e
r
E
3
0
0

S
(34
4
)
YW
C
A
Ut
a
h
E
3
0
0

S
)
(32
2
Sal
t

L
a
k
e

Are
a
Fam
i
l
y

J
u
s
t
i
c
e

C
e
n
t
e
r
(31
0
)
E
3
0
0

S
A-
C
a
r

W
as
h
E

3
0
0

S
)
(3
0
3
Paradise Palm
(307 Broadway)Boozetique & E3 Modern
)(315 Broadway
Utah State
Wine Store
) S 300 E(255
Silverado
Apartments
)(243 S 300 E
The Rainier
) S 300 E(215
Former
Convenient Loan
E 200 S(350 )
Site Map Figure 3