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PFAS Preliminary Assessment Report

Gowen Field, Idaho

i

Table of Contents

Executive Summary .................................................................................................................... 1

1. Introduction ........................................................................................................................ 5

1.1 Authority and Purpose .............................................................................................. 5

1.2 Preliminary Assessment Methods ............................................................................. 5

1.3 Report Organization .................................................................................................. 6

1.4 Facility Location and Description............................................................................... 6

1.5 Facility Environmental Setting ................................................................................... 6

1.5.1 Geology ......................................................................................................... 7

1.5.2 Hydrogeology ................................................................................................. 7

1.5.3 Hydrology ....................................................................................................... 8

1.5.4 Climate ........................................................................................................... 8

1.5.5 Current and Future Land Use ......................................................................... 8

2. Fire Training Areas ........................................................................................................... 13

3. Non-Fire Training Areas ................................................................................................... 15

3.1 AASF ...................................................................................................................... 15

3.2 Central Drainage Ditch ............................................................................................ 15

4. Emergency Response Areas ............................................................................................ 19

5. Adjacent Sources ............................................................................................................. 21

5.1 IDANG Former FTA #1 ............................................................................................ 21

5.2 IDANG Former FTA #2 ............................................................................................ 21

5.3 City Burn Pit ............................................................................................................ 21

5.4 IDANG Hangar 148 ................................................................................................. 21

5.5 IDANG Hangars 1529 & 1530 ................................................................................. 22

5.6 IDANG Hangar 155 ................................................................................................. 22

5.7 Fire Station (Building 138)....................................................................................... 22

5.8 IDANG AFFF Dump 2 ............................................................................................. 22

5.9 2012 Plane Crash ................................................................................................... 22

6. Preliminary Conceptual Site Model .................................................................................. 25

6.1 AOI 1 AASF ............................................................................................................ 25

6.2 AOI 2 Central Drainage Ditch .................................................................................. 26

6.3 AOI 3 IDANG AFFF Dump 1 ................................................................................... 26

7. Conclusions ..................................................................................................................... 31

7.1 Findings .................................................................................................................. 31

7.2 Uncertainties ........................................................................................................... 32

7.3 Potential Future Actions .......................................................................................... 33

8. References ...................................................................................................................... 37
PFAS Preliminary Assessment Report

Gowen Field, Idaho

ii

Figures

Figure ES-1 Summary of Findings

Figure ES-2 Preliminary Conceptual Site Model

Figure 1-1 Facility Location

Figure 1-2 Groundwater Features

Figure 1-3 Surface Water Features

Figure 3-1 Non-Fire Training Areas

Figure 5-1 Adjacent Sources

Figure 6-1 Area of Interest

Figure 6-2 Preliminary Conceptual Site Model, AOI 1

Figure 6-3 Preliminary Conceptual Site Model, AOI 2

Figure 6-4 Preliminary Conceptual Site Model, AOI 3

Figure 7-1 Summary of Findings

Tables

Table ES-1: AOIs at Gowen Field

Table 7-1: AOIs at Gowen Field

Table 7-2: Uncertainties within the PA

Table 7-3: PA Findings Summary

Appendices

Appendix A Data Resources

Appendix B Preliminary Assessment Documentation

B.1 Interview Records

B.2 Visual Site Inspection Checklists

B.3 Conceptual Site Model Information

Appendix C Photographic Log
PFAS Preliminary Assessment Report

Gowen Field, Idaho

iii

Acronyms and Abbreviations

°F

AASF

degrees Fahrenheit

Army Aviation Support Facility

AECOM AECOM Technical Services, Inc.

AFFF aqueous film forming foam

amsl

ANG

above mean sea level

Air National Guard

AOI area of interest

ARNG Army National Guard

bgs below ground surface

CERCLA Comprehensive Environmental Response, Compensation, and Liability

Act

CSM conceptual site model

FTA

gpm

HEF

IDANG

IDARNG

fire training area

gallons per minute

High-Expansion Foam

Idaho Air National Guard

Idaho Army National Guard

IED Installations and Environment Division

PA Preliminary Assessment

PFAS per- and poly-fluoroalkyl substances

PFOA perfluorooctanoic acid

PFOS perfluorooctanesulfonic acid

SI Site Inspection

US United States

USACE United States Army Corps of Engineers

USEPA

USAF

United States Environmental Protection Agency

United States Air Force

VSI visual site inspection
PFAS Preliminary Assessment Report

Gowen Field, Idaho

1

Executive Summary

The United States (US) Army Corps of Engineers (USACE) Baltimore District on behalf of the

Army National Guard (ARNG) Installations & Environment Division, Cleanup Branch contracted

AECOM Technical Services, Inc. (AECOM) to perform Preliminary Assessments (PAs) and Site

Inspections (SIs) for Perfluorooctanesulfonic acid (PFOS) and Perfluorooctanoic acid (PFOA)

Impacted Sites at ARNG Facilities Nationwide. The ARNG is assessing potential effects on human

health related to processes at facilities that used per- and poly-fluoroalkyl substances (PFAS) (a

suite of related chemicals), primarily in the form of aqueous film forming foam (AFFF) released

during firefighting activities or training, although other PFAS sources are possible.

AECOM completed a PA for PFAS at the IDARNG managed portion of Gowen Field (also referred

to as the “installation”), Boise, Idaho, to assess potential PFAS release areas and exposure

pathways to receptors. Gowen Field is leased from the city of Boise by the Idaho ARNG (IDARNG)

and the Idaho Air National Guard (IDANG). The Army Reserves, Navy, and Marine Reserves are

IDARNG tenants. The IDANG-managed portion of Gowen Field is directly adjacent to the

IDARNG installation.

The performance of this PA included the following tasks:

 Reviewed data resources to obtain information relevant to suspected PFAS releases

 Conducted a site visit on 2 February 2019

 Interviewed current IDANG and IDARNG Gowen Field personnel during the site visit including

environmental managers, the IDANG Fire Chief, facility maintenance staff, Army Aviation

Support Facility (AASF) staff, flight operations staff, and other operations staff

 Completed visual site inspections (VSIs) at known or suspected PFAS release locations and

documented with photographs

 Developed a preliminary conceptual site model (CSM) to outline the potential release and

pathway of PFAS for the Areas of Interest (AOIs) and the facility

Three AOIs related to potential PFAS releases were identified at Gowen Field during the PA. The

AOIs are shown on Figure ES-1 and described in Table ES-1 below:

Table ES-1: AOIs at Gowen Field

Area of Interest Name Used by Potential Release

Dates

AOI 1 AASF IDARNG 1990s to 2000s

AOI 2 Central Drainage Ditch IDARNG/IDANG 1970s to 1980s

AOI 3 IDANG AFFF Dump 1 IDANG 2014 - present

Based on documented potential PFAS releases at these AOIs, there is potential for exposure to

PFAS contamination in media at or near the facility. The preliminary CSM for Gowen Field, which

presents the potential receptors and media impacted, is shown on Figure ES-2. Based on the

USEPA Unregulated Contaminant Monitoring Rule 3 data, it was indicated that no PFAS were

detected in a public water system above the United States Environmental Protection Agency

Lifetime Health Advisory level within 20 miles of the facility.
AOI 1

AOI 2

AOI 3

Fivemile Creek

Ridenbaugh Canal

New York Canal

ID ANG AFFF Dump 2

ID ANG AFFF Dump 1 AASF

ID ANG Former FTA #1

ID ANG Hangars 1529 and 1530

Fire Station (Building 138)

ID ANG Hangar 148

ID ANG Hangar 155

2012 Plane Crash

ID ANG Former FTA #2

Central Drainage Ditch

City Burn Pit

Legend

Area of Interest

Potential PFAS Release

Facility Boundary

Water Body

River/Stream

Canal/Ditch

Underground Culvert

0 1,700 3,400 850

Feet

Summary of Findings

Figure ES-1

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SOURCE PATHWAY RECEPTOR

AOI 1 & 2

Human

Activities

Precipitation/

Run-Off

Leaching/

Infiltration

Airborne Soil

particulate

Surface Soil

at AOI

Surface

Water/

sediment

Subsurface

Soil

Shallow

Groundwater

Source Release

Mechanism Media Transportand Migration Media ExposureRoutes

Inhalation of

Dust

Ingestion

Ingestion

Ingestion

Ingestion

Human Receptors:

Current/ Future

Flow-Chart Continues

Partial / Possible Flow

Flow-Chart Stops

Incomplete Pathway

Potentially Complete Pathway

Complete Pathway

Site

Worker

Construction

Worker Resident Trespasser

Site

Worker

Construction

Worker Resident Trespasser

/ / /

/ / /

LEGEND

/ /

/ / /

Figure ES-2

Preliminary Conceptual Site Model

Gowen Field, Idaho

/

/ /

/

/

/

/

PFAS in

Surface and

Subsurface

Soil

Potential

Off-Facility

Source Not

under

Control of

ARNG

/ / /

Nozzle testing and

fuel spill response

Notes:

1. The resident receptor refers to an

off-site resident.

/ / /

3
PFAS Preliminary Assessment Report

Gowen Field, Idaho

4
PFAS Preliminary Assessment Report

Gowen Field, Idaho

5

1. Introduction

1.1 Authority and Purpose

The United States (US) Army Corps of Engineers (USACE) Baltimore District on behalf of the

Army National Guard (ARNG) Installations & Environment Division, Cleanup Branch contracted

AECOM Technical Services, Inc. (AECOM) to perform Preliminary Assessments (PAs) and Site

Inspections (SIs) for Perfluorooctanesulfonic acid (PFOS) and Perfluorooctanoic acid (PFOA)

Impacted Sites at ARNG Facilities Nationwide under Contract Number W912DR-12-D-0014, Task

Order W912DR17F0192, issued 11 August 2017. The ARNG is assessing potential effects on

human health related to processes at their facilities that used per- and poly-fluoroalkyl substances

(PFAS), primarily releases of aqueous film forming foam (AFFF) although other sources of PFAS

are possible. In addition, the ARNG is assessing businesses or operations adjacent to the ARNG

facility (not under the control of ARNG) that could potentially be responsible for a PFAS release.

PFAS are classified as emerging environmental contaminants that are garnering increasing

regulatory interest due to their potential risks to human health and the environment. PFAS

formulations contain highly diverse mixtures of compounds. Thus, the fate of these PFAS

compounds in the environment will vary. The regulatory framework at both federal and state levels

continues to evolve. The US Environmental Protection Agency (USEPA) issued Drinking Water

Health Advisories for PFOA and PFOS in May 2016 (70 parts per trillion), but there are currently

no promulgated national standards regulating PFAS in drinking water. In the absence of federal

maximum contaminant levels, some states have adopted their own drinking water standards for

PFAS. The state of Idaho does not currently have promulgated standards for PFAS in drinking

water.

Gowen Field is occupied by both the Idaho Air National Guard (IDANG) and the Idaho Army

National Guard (IDARNG). This report presents findings of a PA for PFAS at the IDARNG

occupied parcel of Gowen Field (also referred to as the “installation”) in Boise, Idaho, in

accordance with the Comprehensive Environmental Response, Compensation, and Liability Act

(CERCLA), as amended, the National Oil and Hazardous Substances Pollution Contingency Plan

(40 Code of Federal Regulations Part 300), and USACE requirements and guidance.

This PA documents the known fire training areas (FTAs) as well as additional locations where

PFAS may have been released into the environment at Gowen Field. The term PFAS will be used

throughout this report to encompass all PFAS chemicals being evaluated, including PFOS and

PFOA, which are key components of AFFF.

1.2 Preliminary Assessment Methods

The performance of this PA included the following tasks:

 Reviewed data resources to obtain information relevant to suspected PFAS releases

 Conducted a site visit on 2 February 2019

 Interviewed current IDANG and IDARNG Gowen Field personnel during the site visit including

environmental managers, the IDANG Fire Chief, facility maintenance staff, Army Aviation

Support Facility (AASF) staff, flight operations staff, and other operations staff

 Completed visual site inspections (VSIs) at known or suspected PFAS release locations and

documented with photographs

 Developed a preliminary conceptual site model (CSM) to outline the potential release and

pathway of PFAS for the Areas of Interest (AOIs) and the facility
PFAS Preliminary Assessment Report

Gowen Field, Idaho

6

1.3 Report Organization

This report has been prepared in accordance with the USEPA Guidance for Performing

Preliminary Assessments under CERCLA (USEPA, 1991). The report sections and descriptions

of each are:

 Section 1 – Introduction: identifies the project purpose and authority and describes the

facility location, environmental setting, and methods used to complete the PA.

 Section 2 – Fire Training Areas: describes the FTAs at the facility identified during the site

visit.

 Section 3 – Non-Fire Training Areas: describes other locations of potential PFAS releases

at the facility identified during the site visit.

 Section 4 – Emergency Response Areas: describes areas of potential PFAS release at the

facility, specifically in response to emergency situations.

 Section 5 – Adjacent Sources: describes sources of potential PFAS release adjacent to the

facility that are not under the control of ARNG.

 Section 6 – Conceptual Site Model: describes the pathways of PFAS transport and

receptors at each AOI.

 Section 7 – Conclusions: summarizes the data findings and presents the conclusions of the

PA.

 Section 8 – References: provides the references used to develop this document.

 Appendix A – Data Resources

 Appendix B – Preliminary Assessment Documentation

 Appendix C – Photographic Log

1.4 Facility Location and Description

The Boise Airport is located in Ada County within the boundary of the city of Boise, in western

Idaho (Figure 1-1). The Gowen Field property is leased from the city of Boise by the IDARNG

and the IDANG. The Army Reserves, Navy Reserves, and Marine Reserves are IDARNG tenants.

The IDANG-managed portion of Gowen Field is directly adjacent to the IDARNG installation.

In 1941, construction at Boise Air Base began. Later that year, the installation officially became

Gowen Field, which remained an active Army Air Corps Base during WWII. After the end of the

war, Gowen Field was turned back over to the city of Boise in 1946. The IDANG was established

concurrently with the United States Air Force (USAF) in 1947 and moved to Gowen Field shortly

after. The IDARNG currently occupies approximately 240 acres of Gowen Field on the

southwestern portion (Idaho National Guard, 2019).

1.5 Facility Environmental Setting

Gowen Field is in the Boise River Valley, on a generally flat plot of land with an average elevation

of about 2,800 feet above mean sea level (amsl). Mountains to the south and north of the

installation rise up to elevations of 8,500 feet amsl. The Boise River is to the north and northeast

of the site, at distances varying between 3.5 – 4 miles. The Snake River is to the southwest of the

site at distances greater than 20 miles.
PFAS Preliminary Assessment Report

Gowen Field, Idaho

7

1.5.1 Geology

Gowen Field is located in the Boise River Valley, within the broader Western Snake River Plain,

just south of the foothills of the mountainous terrain of central Idaho. The Western Snake River

Plain is a fault bounded intracontinental rift basin (Wood & Clemens, 2002). The Pliocene and

Pleistocene geologic history of the Boise Valley includes crustal rifting, basin filling, river incision,

eruptions of lava flows, and major flooding.

The Chalk Hills Formation constitutes the earliest sedimentation in the basin, characterized by a

succession of fluvio-lacustrine sediments resulting from interconnected lakes, meandering

streams, and lacustrine delta deposits. These lake levels declined, resulting in erosion of part of

the Chalk Hills Formation in the Boise area. A subsequent rise in lake level led to the deposition

of another lacustrine sequence which includes shoreline sands, small deltas, and lacustrine mud

in the deeper parts of the basin. These deposits are mapped as the Terteling Springs Formation

(Wood & Clemens, 2002).

Spillover of this ancient lake system resulted in a slow lowering of the lake level and filling of the

shrinking lake basins with interbedded mud and sand of lacustrine delta systems of the Glenns

Ferry Formation (Wood & Clemens, 2002).

In more recent geologic history, terraces were formed by rapid fluvial downcutting followed by

coarse gravel deposition (Othberg, 1994).

Gowen Field sits above the Pleistocene terrace gravel deposits (Figure 1-2), which consist of

unconsolidated silt, sand, and well-sorted gravel beds characterized by cut-and-fill channels,

inclined bedding, and cross-bedding.

1.5.2 Hydrogeology

Groundwater beneath the installation has been reported to range from as shallow as 120 feet

below ground surface (bgs) to depths greater than 200 feet bgs. The installation is currently

supplied potable water by Suez Water Idaho, Inc. (Suez), a local provider, although some wells

on-site were reported as being used for irrigation. The base has used both shallow and deep

aquifers for its water supply in the past.

The aquifer system in the Boise area consists of complex series of interbedded, tilted, faulted,

and eroded sediments extending to depths of over 6,000 feet. These sedimentary aquifers contain

shallow, local flow systems, and a deeper, regional groundwater system (Petrich, 2004).

Within the Boise area, multiple wells have tapped into a deep aquifer (at 660 feet bgs). These

wells are capable of yielding 180 to 1,400 gallons per minute (gpm). Suez Water wells are located

approximately 2 miles north of the installation and have a 9.1-million-gallons-per-day capacity

(Leidos, 2014). Several wells listed for domestic use are located 2-3 miles to the north of the 1-3

miles to the east of the installation. Many wells of unknown use are located around the installation

within a 1-mile buffer (IDWR, 2019). It is possible that some of these wells are used for potable

purposes.

Results of groundwater characterization and modeling in this area show that the deeper aquifer

flows south toward the Snake River (Figure 1-2) (Petrich, 2004 and Petrich & Urban, 2004). This

work suggests that recharge to the deep aquifer occurs primarily in the eastern portion of the

Boise River Valley where parts of the Idaho Group are exposed at the earth’s surface, and ultimate

discharge occurs into major rivers. In the area of Gowen Field, discharge to the Snake River

drives the deep groundwater flow direction to the south. No portion of the recharge zone for the

deep aquifer is coincident with Gowen Field.
PFAS Preliminary Assessment Report

Gowen Field, Idaho

8

Recharge to the shallow groundwater systems in the Boise River Valley occurs primarily from

seepage from the canals and infiltration, mostly associated with irrigation. This creates variable

shallow groundwater flow directions across the Boise River valley (Petrich & Urban, 2004).

Previous studies in the Gowen Field area have suggested that shallow groundwater flows in a

northeast to easterly direction (Leidos, 2019).

1.5.3 Hydrology

Gowen Field is located within the Boise River drainage basin, a semi-arid area that receives

annual precipitation of 11.73 inches (NOAA, 2019). Surface drainage at Gowen Field is controlled

both by the local surface topography and a system of drainage ditches. The most important

drainage ditch generally traverses the installation with flow from east to west. This drainage ditch

originates as the remnant of an intermittent stream on the adjacent IDANG property, before

traversing the IDARNG property and discharging to an off-installation retention pond, a

stormwater control feature that maintains a permanent pool of water (Figure 1-3). The retention

pond is not owned by the IDARNG.

Fivemile Creek, an intermittent stream that flows only during periods of heavy rainfall or snowmelt

runoff, runs parallel to and south of West Gowen Road. The creek originates in the mountains,

approximately 3 miles away and discharges into the New York Canal, approximately 1 mile

downstream of the property. This canal eventually discharges into the Boise River, which is used

for crop irrigation (Leidos, 2014). None of these surface water features are used for drinking water

in Boise.

1.5.4 Climate

Gowen Field is located within Ada County, Idaho, which has a semi-arid climate, with hot and dry

summers and moderately cold winters. The average annual temperature is 52.5 degrees

Fahrenheit (°F), ranging from an average winter low of 25.6°F, to an average summer high of

87.5°F. The mean annual precipitation in Boise is approximately 11.73 inches, with most of the

precipitation occurring from November through May each year (NOAA, 2019). The average

number of days with over 0.1 inches or more of precipitation is over 39. Ada County only receives

an annual snowfall average of 12.48 inches (Leidos, 2019).

1.5.5 Current and Future Land Use

At present, the IDARNG property at Gowen Field consists of approximately 240 acres and is

located adjacent to the Boise Airport and IDANG property. The IDARNG installation consists

mostly of operations and support buildings, as well as an AASF. Access to the installation is

controlled. Land surrounding the installation to the north, east, and west is used for industrial

purposes and airport operations. Land to the south of the installation is used for agricultural

purposes and livestock grazing. Residential areas are not located immediately adjacent to the

installation. The closest residential areas are located approximately 0.75 miles to the north of the

northern edge of the installation.

Gowen Field is located entirely within Ada County, within the city of Boise, Idaho. Based on official

2017 estimates from the US Census Bureau, Boise’s population is 226,570, and it is the largest

city in Idaho (USCB, 2017). The IDARNG has been operating at Gowen Field since 1946, and

land use is not expected to change in the future.
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Surface Water Features

Base Map: Source: Esri, DigitalGlobe, GeoEye,

Earthstar Geographics, CNES/Airbus DS, USDA, USGS,

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Legend

Facility Boundary

Water Body

River/Stream

Canal/Ditch

Underground Culvert

Surface Water Flow

Direction

Watersheds

Crane Creek-Boise

River

Eightmile Creek

Fivemile Creek

0 0.5 1 0.25

Miles

1
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2. Fire Training Areas

No FTAs were identified at the IDARNG Gowen Field installation during the PA. According to

interviews with the Fire Chief at the installation, IDARNG fire training activities have only occurred

at the city of Boise burn pit, which is located off-site, about 1.6 miles away, from at least 1998 to

present. This burn pit is discussed in detail in Section 5. The IDARNG has been in operation at

the installation since the early 1946however, no information was obtained about fire training

activities associated with the IDARNG or the IDANG prior to 1998.
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3. Non-Fire Training Areas

Two non-FTAs where PFAS was potentially released was identified during the PA. A description

of the non-FTA is presented below, and the non-FTA is shown on Figure 3-1. Interview records

appear in Appendix B, and photographs appear in Appendix C.

3.1 AASF

The Gowen Field AASF hangar, flight line, and apron are located in the southeast corner of the

IDARNG Gowen Field installation. Information on AFFF storage and use at the AASF prior to the

1990s was not obtained. The geographic coordinates of the center of the AASF hangar are

43°33'22.6"N 116°13'00.1"W (Figure 3-1). The AASF consists of a main hangar, built in 2002 –

2003, a smaller hangar built in 2016 – 2017, a wash rack, flightline, small maintenance building,

and an adjacent drainage field (Figure 3-1 inset).

A 200-gallon Tri-MaxTM AFFF unit is currently stored inside the small hangar at the AASF and

contains the only AFFF still on IDARNG property at Gowen Field. The AFFF unit is a hoseoperated system and is not connected to a suppression system in the building. There was no

reported usage of this unit, and no evidence of spills or leaking in the vicinity. Another 200 to 225-

gallon Tri-MaxTM unit is stored outside of the main hangar, on the east end of the AASF. This unit

is currently empty. Five empty extinguishers of various sizes (30-gallons or less) are also stored

in this outdoor area. It is unclear what the contents of these extinguishers once were. According

to observations made during the PA site visit and a technical memorandum for a sewer

investigation provided by IDARNG (Murraysmith, 2019), storm and floor drains on the flight line

and inside the AASF hangars drain to the east and eventually discharge to the drain field adjacent

to the AASF or to the sanitary sewer system. Water entering the drain field flows through one of

two grease/sand traps and is discharged to the subsurface via a ‘seepage trench,’ which is a lined

gravel pit (Figure 3-1). A valve system is also in place that can direct water off-site to the sanitary

sewer system.

Historically, Tri-MaxTM 30-gallon units containing AFFF were discharged in the vicinity of the AASF

from 2005 – 2015. There were about 12 to 15 30-gallon Tri-MaxTM units on the flight line during

this time. It was reported that these units were fully expended before they were removed from the

site, although the exact location of the foam discharge is unknown. Additionally, nozzle testing of

the Tri-Max units was conducted about once every three years from 2005 to 2015 on the wash

rack area and over the fence from the east compound into the adjacent grassy area. A staff

member at the AASF reported that AFFF was also discharged on the flight line to clean up fuel

spills on multiple occasions. The number of fuel spills and the quantity of AFFF used during these

fuel spills is unknown.

3.2 Central Drainage Ditch

The Gowen Field Central Drainage Ditch begins on IDANG property off the northeast corner of

the facility. The drainage ditch crosses onto IDARNG property at approximate geographic

coordinates 43°33'28.6"N 116°13'05.9"W. The ditch flows to the west and briefly crosses back

onto IDANG property for approximately 500-ft, after which it crosses back onto IDARNG property

and continues west across the north half of the installation until it drains into a retention pond

adjacent to the west boundary of the installation (Figure 3-1).

Documented IDANG activities including historical AFFF releases have potentially entered the

Central Drainage Ditch on IDARNG property. In particular, fire training activities at IDANG Former

FTA #1, which is discussed in detail in Section 5, may have had an impact on the Central

Drainage Ditch. AFFF discharges at the IDARNG AASF building discussed in Section 3.1 would
PFAS Preliminary Assessment Report

Gowen Field, Idaho

16

not have impacted the Central Drainage Ditch. There is no surface water flow pathway from the

AASF to the Central Drainage Ditch.
Fivemile Creek

ID ANG AFFF Dump 1

AASF

Central Drainage Ditch

Legend

Potential PFAS Release

Facility Boundary

Water Body

River/Stream

Canal/Ditch

Underground Culvert

0 900 1,800 450

Feet

Non-Fire Training Area

Figure 3-1

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DS, USDA, USGS, AeroGRID, IGN, and the GIS User Community

Drain Field

Maintenance

Building

Wash Rack

Apron

Seepage Trench

AASF

1
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4. Emergency Response Areas

Information obtained during the PA identified no instances of emergency responses at the

IDARNG Gowen Field installation from 1998 to present. Information on emergency responses

prior to this time was not obtained. The AFFF tank in the enclosed aircraft wash rack has

reportedly never been used, and Tri-MaxTM units were never used for emergency response from

at least 1998 to present.

The Gowen Field Fire Department covers emergency response to the IDARNG, IDANG, and

municipal airport at Gowen Field. None of the staff interviewed during the PA site visit were aware

of any event at the IDARNG part of the installation in which the Gowen Field Fire Department

responded and used AFFF. Interview records appear in Appendix B.
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5. Adjacent Sources

Nine potential off-facility sources of PFAS not under control of the IDARNG were identified during

the PA. The sources are mentioned in the Final Preliminary Assessment Report for Perfluorinated

Compounds at Boise Air National Guard Boise, Idaho which details the PFAS investigation

conducted by the adjacent IDANG facility. A description of each potential off-facility source is

presented below, and locations are shown on Figure 5-1.

5.1 IDANG Former FTA #1

The 230-foot diameter Former FTA #1 was in use from 1974 to 1989 as an unlined training area

at which AFFF was released directly to the ground surface. Soils from the burn pit were disposed

of at an off-facility landfill (CH2M Hill, 2015). Soil and groundwater samples taken at this location

showed detections of PFAS (Leidos, 2019). The Former FTA #1 is located approximately 370 feet

cross-gradient of the assumed regional groundwater flow direction but is located directly adjacent

to the Central Drainage Ditch that eventually flows onto IDARNG property.

5.2 IDANG Former FTA #2

The Former FTA #2 was used for training activities from 1953 to 1974, with an average of 16

firefighting events held each year (HAZWRAP, 1994). Documentation reviewed during this PA

does not specifically mention the use of AFFF at this location. However, given the documented

use of AFFF for similar activities at the Former FTA #1, it is possible that AFFF was discharged at

the Former FTA #2 from 1970 to 1974. The Former FTA #2 is located upgradient of the installation

in terms of deep regional groundwater flow and downgradient of the installation in terms of shallow

groundwater flow.

5.3 City Burn Pit

The installation Fire Chief reported Gowen Field fire personnel conducted semi-regular training

activities using AFFF at the City Burn Pit, located approximately 1.6 miles to the east of Gowen

Field, from at least 1998 to 2015. The Fire Chief also indicated that municipal fire departments

used AFFF at this location. The amount and type of AFFF used is unknown, and documentation

is not maintained by the installation fire department. The City Burn Pit is located downgradient of

the shallow groundwater flow in this area and cross-gradient of the deep regional groundwater

flow (HAZWRAP, 1994).

5.4 IDANG Hangar 148

The IDANG Hangar 148 has been equipped with an AFFF fire suppression system, including a

400-gallon AFFF tank, since 1982. Testing of the suppression system has occurred historically.

AFFF was either allowed to enter the floor drains, which lead to the city of Boise waste water

treatment plant, or on occasion, foam was vacuumed up and disposed of at the AFFF Dump 2

(Section 5.8). It was reported that no AFFF releases have escaped the confines of the hangar.

PFAS were detected in soil, sediment, and surface water samples collected during a subsequent

PFAS Site Inspection (SI) at this location (Leidos, 2019). IDANG Hangar 148 is located upgradient

of the installation in terms of deep regional groundwater flow and downgradient of the installation

in terms of shallow groundwater flow.
PFAS Preliminary Assessment Report

Gowen Field, Idaho

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5.5 IDANG Hangars 1529 & 1530

The IDANG Hangars 1529 & 1530 are attached and share a fire suppression system with a 600-

gallon AFFF tank. Testing of the suppression system has occurred, after which the AFFF either

drained to the central floor drain that connects to the city of Boise waste water treatment plant, or

on occasion, AFFF was vacuumed up and disposed of at the AFFF Dump 2 (Section 5.8) location.

It was reported that no AFFF releases have escaped the confines of the hangars. PFAS were

detected in sediment samples collected during a PFAS SI at this location (Leidos, 2019). IDANG

Hangars 1529 & 1530 are located upgradient of the installation in terms of deep regional

groundwater flow and downgradient of the installation in terms of shallow groundwater flow.

5.6 IDANG Hangar 155

The IDANG Hangar 155 has two large bays with floor drains that lead to an oil/water separator

that discharges to the city of Boise waste water treatment plant. The fire suppression system in

the building was charged with a 600-gallon AFFF tank until 2005, when it was replaced with highexpansion foam (HEF). No reported releases have escaped the confines of the hangar. PFAS

were detected in soil and sediment samples collected during a PFAS SI at this location (Leidos,

2019). IDANG Hangar 155 is located upgradient of the installation in terms of deep regional

groundwater flow and downgradient of the installation in terms of shallow groundwater flow.

5.7 Fire Station (Building 138)

The Fire Station has been operational since 1994 and serves the IDANG and the IDARNG at

Gowen Field. AFFF is carried on four engines in the station, with between 55 and 210 gallons on

each vehicle. An additional 880 gallons of AFFF are stored in 55-gallon drums with secondary

containment measures in place. Trench drains in the building lead to the city of Boise waste water

treatment plant. No reported AFFF releases have escaped the confines of the building (CH2M

Hill, 2015). PFAS were detected in soil, groundwater, and sediment samples collected during a

PFAS SI at this location (Leidos, 2019). The Fire Station (Building 138) is located upgradient of

the installation in terms of deep regional groundwater flow and downgradient of the installation in

terms of shallow groundwater flow.

5.8 IDANG AFFF Dump 2

AFFF released at IDANG hangars was occasionally disposed of in two locations, and one is the

IDANG AFFF Dump 2. It is unknown how much AFFF was moved to Dump 2. AFFF Dump 2 is

located approximately 240 feet south of IDARNG property, down-gradient of the assumed regional

groundwater flow direction, and upgradient of the IDARNG facility relative to assumed shallow

groundwater flow. PFAS were detected in soil and groundwater samples collected during a PFAS

SI at this location (Leidos, 2019).

5.9 2012 Plane Crash

In February 2012, IDANG responded to a private plane crash located on the south side of the

main runway, about 0.4 miles from IDARNG property, during which, an unknown quantity of AFFF

was used to extinguish the flames (Leidos, 2019). The 2012 Plane Crash Location is located

upgradient of the installation in terms of deep regional groundwater flow and downgradient of the

installation in terms of shallow groundwater flow.
Fivemile Creek

New York Canal

ID ANG AFFF Dump 2

ID ANG Former FTA #1

ID ANG Hangars 1529 and 1530

Fire Station (Building 138)

ID ANG Hangar 148

ID ANG Hangar 155

2012 Plane Crash

ID ANG Former FTA #2

City Burn Pit

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Legend

Potential PFAS Release

Facility Boundary

Water Body

River/Stream

Canal/Ditch

Underground Culvert

0 1,700 3,400 850

Feet

Adjacent Sources

Figure 5-1

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Preliminary Assessment for PFAS at Gowen Field, ID

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1:20,400 ­ 12420 Milestone Center Drive

Germantown, MD 20876

Base Map: Source: Esri, DigitalGlobe, GeoEye, Earthstar Geographics, CNES/Airbus

DS, USDA, USGS, AeroGRID, IGN, and the GIS User Community


PFAS Preliminary Assessment Report

Gowen Field, Idaho

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PFAS Preliminary Assessment Report

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6. Preliminary Conceptual Site Model

Based on the PA findings, three AOIs were identified at Gowen Field: AOI 1 AASF, AOI 2 Central

Drainage Ditch, and AOI 3 IDANG AFFF Dump 1. The AOIs are shown on Figure 6-1. The

following sections describe the CSM components and the specific CSMs developed for each AOI.

The CSM identifies the three components necessary for a potentially complete exposure pathway:

(1) source, (2) pathway, (3) receptor. If any of these elements are missing, the pathway is

considered incomplete.

In general, the potential PFAS exposure pathways are ingestion and inhalation. Human exposure

via the dermal contact pathway may occur, and current risk practice suggests it is an insignificant

SDWKZD\ FRPSDUHG WR LQJHVWLRQ KRZHYHU H[SRVXUH GDWD IRU GHUPal pathways is sparse and

continues to be the subject of PFAS toxicological study. Receptors for Gowen Field include site

workers, construction workers, residents, and trespassers. The CSMs for each AOI indicate which

specific receptors could potentially be exposed to PFAS.

6.1 AOI 1 AASF

AOI 1 is the AASF. PFAS releases to the soil and pavement by the IDARNG occurred multiple

times during nozzle testing from 2005 to 2015. The AASF is located on the eastern boundary of

the installation. No remediation activities have occurred at AOI 1.

PFAS are water soluble and can migrate readily from soil and pavement to groundwater, which is

estimated to begin at 120 to 200 feet bgs. Because PFAS releases to surface soil at AOI 1 have

occurred, PFAS may migrate from the surface soil to the groundwater via leaching. PFAS releases

to the pavement would enter the storm drains and release to the subsurface soil via the drain field

adjacent to the AASF. Drinking water for Gowen Field is supplied by a local supplier, Suez Water,

which has two wells located 2 miles north of the installation, and one well 4,000 feet to the west

of the installation. The entire Suez Water system supplies about 214,000 people in addition to

Gowen Field (Leidos, 2019). As of the date of this report, AECOM does not have knowledge of

any testing for PFAS done on Suez supplied water. According to the Idaho Department of Water

Resources data, hundreds of private wells are located within a 3-mile radius of the installation,

with screen intervals at varying depths (IDWR, 2019). Figure 6-1 shows two water supply wells

within the installation footprint, however, these wells are no longer active and do not represent a

potential groundwater receptor.

Ground-disturbing activities to surface soil at AOI 1 may result in site worker, construction worker,

and trespasser exposure to potential PFAS contamination. The pathway for inhalation of airborne

soil particulates is potentially complete for the same receptors. Ground-disturbing activities to

subsurface soil could result in potential construction worker exposure. Based on information

gathered during the PA, three public supply wells are located within 2 miles of the facility

boundary+RZHYHUUHFKDUJHIRUWKHGHHSDTXLIHUGRHVQRWRFFXULQWKH*RZHQ)LHOGIRRWSULQW

and it is unlikely that these wells will be impacted. Therefore, the deep groundwater pathway to

all receptors is incomplete. However, many private water wells are located downgradient of AOI

1. These private drinking water wells may be screened in shallow aquifers and could potentially

be impacted by PFAS releases at AOI 1. Therefore, the exposure pathway for groundwater to offinstallation residents is potentially complete. 1R VXUIDFH ZDWHUIHDWXUHVIORZ WKURXJKWKLV$2,

therefore, surface water and sediment exposure pathways are incomplete for AOI 1. The

preliminary CSM for AOI 1 is shown on Figure 6-2.
PFAS Preliminary Assessment Report

Gowen Field, Idaho

26

6.2 AOI 2 Central Drainage Ditch

AOI 2 is the Central Drainage Ditch. AFFF releases to the soil and pavement from off-facility

IDANG sources discussed in Section 5 may have flowed to the Central Drainage Ditch within

Gowen Field. AFFF discharges at the IDARNG AASF building discussed in Section 6.1 would

not have impacted the Central Drainage Ditch. There is no surface water flow pathway from the

AASF to the Central Drainage Ditch. No remediation activities have occurred at AOI 2.

During a 2019 PFAS SI (Appendix A) conducted by the IDANG, PFAS were detected in soil and

groundwater at the IDANG Former FTA #1, which is adjacent to the easternmost portion of the

central drainage ditch (Leidos, 2019). PFAS were also detected in surface water and sediment

samples taken from the outfall of the Central Drainage Ditch at the western boundary of the

IDARNG Gowen Field facility during the 2019 IDANG PFAS SI. Many portions of the Central

Drainage Ditch on the IDARNG facility are unlined, and there is the potential for PFAS present in

the surface water or sediment within the ditch to leach into the groundwater at Gowen Field.

Ground disturbing activities to surface soil and sediment at AOI 2 may result in site worker,

construction worker, and trespasser exposure to potential PFAS contamination. The pathway for

airborne soil particulates to those receptors is also potentially complete. Ground-disturbing

activities to subsurface soil could result in construction worker exposure, and this pathway is

potentially complete. Recharge to the deep aquifer which feeds public drinking water supply

does not occur in the Gowen Field footprint. Therefore, the deep groundwater pathway to all

receptors is incomplete. Private wells located near Gowen Field have the potential to be

impacted by PFAS contamination leaching from sediment and soil to shallow groundwater at

AOI 2. Therefore, the exposure pathway for shallow groundwater to off-installation residents is

potentially complete. Given the detections of PFAS in surface water and sediment at the Central

Drainage Ditch during the 2019 IDANG PFAS SI, the exposure pathways for site workers,

construction workers, and trespassers is potentially complete for these media. The preliminary

CSM for AOI 2 is shown on Figure 6-3.

6.3 AOI 3 IDANG AFFF Dump 1

AOI 3 is the IDANG AFFF Dump 1. AFFF releases to the soil as a result of IDANG dumping of

used AFFF have occurred at least six times from 2014 – present. This area is located on the

eastern boundary of the installation. No remediation activities have occurred at AOI 3.

During a 2019 PFAS SI (Appendix A) conducted by the IDANG, PFAS were detected in soil and

groundwater samples collected (Leidos, 2019). This SI report shows the dump location at least

partially on IDARNG property.

Ground disturbing activities to surface soil at AOI 3 may result in site worker, construction worker,

and trespasser exposure to potential PFAS contamination. The pathway for airborne soil

particulates to those receptors is potentially complete. Ground-disturbing activities to subsurface

soil could result in construction worker exposure, and this pathway is potentially complete.

Recharge to the deep aquifer which feeds public drinking water supply does not occur in the

Gowen Field footprint. Therefore, the deep groundwater pathway to all receptors is incomplete.

Private wells located near Gowen Field have the potential to be impacted by PFAS contamination

leaching from soil to shallow groundwater at AOI 3. Therefore, the exposure pathway for shallow

groundwater to off-installation residents is potentially complete. Surface water and sediment

exposure pathways are incomplete at AOI 3, given the absence of these media. The preliminary

CSM for AOI 3 is shown on Figure 6-4.
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AOI 3

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Fivemile Creek

New York Canal

Legend

Area of Interest

Potential PFAS Release

Facility Boundary

Water Body

River/Stream

Canal/Ditch

Underground Culvert

Surface Water Flow

Direction

Inferred Shallow

Groundwater Flow

Direction

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Figure 6-1

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2
Media

SOURCE PATHWAY RECEPTOR

AOI 1 Nozzle testing and

fuel spill response

Human

Activities

Precipitation/

Run-Off

Leaching/

Infiltration

Airborne Soil

particulate

Surface Soil

at AOI

Surface

Water/

sediment

Subsurface

Soil

Shallow

Groundwater

Source Release

Mechanism Media Transportand Migration Media ExposureRoutes

Inhalation of

Dust

Ingestion

Ingestion

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Ingestion

Human Receptors:

Current/ Future

Flow-Chart Continues

Partial / Possible Flow

Flow-Chart Stops

Incomplete Pathway

Potentially Complete Pathway

Complete Pathway

Site

Worker

Construction

Worker Resident Trespasser

Site

Worker

Construction

Worker Resident Trespasser

/ / /

/ /

LEGEND

/ /

/ / /

Figure 6-2

Preliminary Conceptual Site Model

AOI 1

Gowen Field, Idaho

/ /

/

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PFAS in

Surface and

Subsurface

Soil

Potential

Off-Facility

Source Not

under

Control of

ARNG

Notes:

1. The resident receptor refers to an

off-site resident.

/ /

/

/

2
SOURCE PATHWAY RECEPTOR

AOI 2

No ARNG

Source at

AOI 2

Human

Activities

Precipitation/

Run-Off

Leaching/

Infiltration

Airborne Soil

particulate

Surface Soil

at AOI

Surface

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sediment

Subsurface

Soil

Shallow

Groundwater

Source Release

Mechanism Media Transportand Migration Media ExposureRoutes

Inhalation of

Dust

Ingestion

Ingestion

Ingestion

Ingestion

Human Receptors:

Current/ Future

Flow-Chart Continues

Partial / Possible Flow

Flow-Chart Stops

Incomplete Pathway

Potentially Complete Pathway

Complete Pathway

Site

Worker

Construction

Worker Resident Trespasser

Site

Worker

Construction

Worker Resident Trespasser

/ / /

/ / /

LEGEND

/ /

/ / /

Figure 6-3

Preliminary Conceptual Site Model

AOI 2

Gowen Field, Idaho

/

/ /

/

/

/

/

PFAS in

Surface Soil

Potential

Off-Facility

Source Not

under

Control of

ARNG

/ / /

Notes:

1. The resident receptor refers to an

off-site resident.

/ / /

2
SOURCE PATHWAY RECEPTOR

AOI 3

No ARNG

Source at

AOI 3

Human

Activities

Precipitation/

Run-Off

Leaching/

Infiltration

Airborne Soil

particulate

Surface Soil

at AOI

Surface

Water/

sediment

Subsurface

Soil

Shallow

Groundwater

Source Release

Mechanism Media Transportand Migration Media ExposureRoutes

Inhalation of

Dust

Ingestion

Ingestion

Ingestion

Ingestion

Human Receptors:

Current/ Future

Flow-Chart Continues

Partial / Possible Flow

Flow-Chart Stops

Incomplete Pathway

Potentially Complete Pathway

Complete Pathway

Site

Worker

Construction

Worker Resident Trespasser

Site

Worker

Construction

Worker Resident Trespasser

/ / /

/ / /

LEGEND

/ /

/ / /

Figure 6-4

Preliminary Conceptual Site Model

AOI 3

Gowen Field, Idaho

/

/ /

/

/

/

/

PFAS in

Surface Soil

Potential

Off-Facility

Source Not

under

Control of

ARNG

Notes:

1. The resident receptor refers to an

off-site resident.

/ / /


PFAS Preliminary Assessment Report

Gowen Field, Idaho

31

7. Conclusions

This report presents a summary of available information gathered during the PA on the use and

storage of AFFF and other PFAS-related activities at Gowen Field. The PA findings are based on

the information presented in Appendix A and Appendix B.

7.1 Findings

Three AOIs related to potential PFAS release were identified (Table 7-1) at Gowen Field during

the PA (Figure 7-1).

Table 7-1: AOIs at Gowen Field

Potential Release

Area Used By Determination Rationale

AOI 1 AASF IDARNG Reported AFFF releases

AFFF releases occurred between

2005 and 2015 multiple times per

year during nozzle testing, fuel

spills, and to empty Tri-Max units

prior to disposal. Water and AFFF

captured by storm drains at AOI 1 is

released to the adjacent drain field

via a subsurface seepage trench.

AOI 2 Central

Drainage Ditch

IDARNG

& IDANG

Reported AFFF releases at

adjacent off-facility IDANG

location

AFFF releases occurred during the

1970s and 1980s at the off-facility

IDANG Former FTA #1 which is

adjacent to the most upgradient

portion of the Central Drainage

'LWFK 3)$6 ZHUH GHWHFWHG in

environmental media during a 2019

IDANG PFAS SI at the former FTA

and at the outfall of the Central

Drainage Ditch. AFFF releases at

the IDARNG AASF have not

impacted the Central Drainage

Ditch.

AOI 3 IDANG AFFF

Dump 1

IDARNG

& IDANG

Reported AFFF dumping by

IDANG

Dumping of AFFF occurred at least

6 times from 2014 - present.

Numerous potential off-facility sources of PFAS were considered in the local area surrounding

Gowen Field. These include:

 IDANG Former FTA #1 – AFFF was used as a part of fire training activities for 14 years,

and a PFAS SI at the base reported detections of PFAS in soil and groundwater,W LV

possible that AFFF entered the adjacent Central Drainage Ditch which flows onto the

IDARNG facility

 IDANG Former FTA #2 – Given the time period of operation, AFFF was potentially used in

this location

 Current FTA – AFFF was used for training activities by IDANG, IDARNG, and municipal

firefighting personnel for over 15 years
PFAS Preliminary Assessment Report

Gowen Field, Idaho

32

 IDANG Hangar 148 – testing of the AFFF-charged fire suppression system has occurred

multiple times

 IDANG Hangars 1529 & 1530 – testing of the AFFF-charged fire suppression system has

occurred multiple times

 IDANG Hangar 155 – the AFFF suppression system, which was operational until 2005,

may have been released inside the hangar

 Fire Station (Building 138) – AFFF is carried on trucks and stored in drums inside the fire

station

 IDANG AFFF Dump 2 – AFFF has been dumped in this area by the IDANG at least 1 time

 2012 Plane Crash – an unknown quantity of AFFF was used to respond to a private plane

crash 0.4 miles to the north of the installation

Based on documented potential PFAS releases at AOI 1 and the documented PFAS presence at

AOI 2 and AOI 3, there is potential for exposure to PFAS contamination in media at or near the

facility. The preliminary CSM for Gowen Field is shown on Figure 6-2, which presents the potential

receptors and media impacted.

7.2 Uncertainties

A number of information sources were investigated during this PA to determine the potential for

PFAS-containing materials to have been present, used, or released at the facility. Historically,

documentation of PFAS use was not required because PFAS were considered benign. Therefore,

records were not typically kept by the facility or available during the PA on the use of PFAS in

training, firefighting, or other non-traditional activities, or on its disposal.

The conclusions of this PA are predominantly based on the information provided during interviews

with personnel who had direct knowledge of PFAS use at the facility. However, interview

information only extended back to 1995. Gathered information has a degree of uncertainty due to

the absence of written documentation, the limited number of personnel with direct knowledge due

to staffing changes, the time passed since PFAS was first used (1969 to present), and a reliance

on personal recollection. Previous environmental reports and data resources were used to

supplement the information gathered during interviews (Appendix A). Inaccuracies may arise in

potential PFAS release locations, dates of release, volume of releases, and the concentration of

AFFF used. There is also a possibility the PA has missed a source of PFAS, as the science of

how PFAS may enter the environment continually evolves.

In order to minimize the level of uncertainty, readily available data regarding the use and storage

of PFAS were reviewed, current personnel were interviewed, multiple persons were interviewed

for the same potential source area, and potential source areas were visually inspected. Table 7-

2 summarizes the uncertainties associated with the PA:

Table 7-2: Uncertainties within the PA

Area of Interest Source of Uncertainty

General Interviewees direct knowledge of fire training activities

only extended back to 1998 and to 1995 for general site

operations. IDARNG occupancy began in 1946, leaving

at least a 20-year gap in information relative to the
PFAS Preliminary Assessment Report

Gowen Field, Idaho

33

approximate earliest use of AFFF by the military (about

1970).

General There are varying flow directions in the deep and

shallow aquifers in the Boise area, and the exact

groundwater flow directions were not determined in this

PA.

AOI 1 AASF The amount and type of AFFF released in this area is

unknown.

AOI 2 Central Drainage

Ditch

The amount of AFFF that entered the drainage ditch

from the adjacent IDANG sources is unknown.

AOI 3 IDANG AFFF Dump

1

The frequency and volume of AFFF dumped from 2014

– present is unknown.

7.3 Potential Future Actions

Interviews and records (covering 1990s to present) indicate that current or former IDARNG

activities may have resulted in potential PFAS releases at AOI 1, and former IDANG activities

have resulted in potential PFAS releases to AOI 2 and AOI 3. Based on the CSM developed for

the AOIs, there is potential for receptors to be exposed to PFAS contamination in soil,

groundwater, surface water, and sediment. The following table summarizes the rationale used to

determine if the AOI should be considered for further investigation under the CERCLA process

and undergo a Site Inspection (SI).

Table 7-3: PA Findings Summary

Area of

Interest AOI Location Rationale Potential FutureAction

AOI 1 AASF 43°33'22.6"N

116°13'00.1"W

Unknown quantity of AFFF

released during nozzle

testing activities and fuel

spill response from 2005 to

2015.

Proceed to an SI, focus

on soil, and shallow

groundwater.

AOI 2 Central

Drainage Ditch

Enters facility at

43°33'28.6"N

116°13'05.9"W

Exits facility at

43°33’38.7’’N

116°14’11.4’’W

Unknown quantity of AFFF

entered the ditch during

IDANG fire training activities

adjacent to the facility in the

1970s and 1980s.

Proceed to an SI, focus

on soil, shallow

groundwater, surface

water, and sediment.1

AOI 3 IDANG

AFFF Dump 1

43°33’24’’ 1

116°12’43’’ W

Unknown quantity of AFFF

dumped by IDANG from

2014 – present.

Proceed to an SI, focus

on soil, shallow

groundwater, surface

water, and sediment.1

1

 = ARNG and ANG will evaluate the need for an SI at AOI 2 and AOI 3 pending a decision on which entity will conduct

future investigations at these locations.
PFAS Preliminary Assessment Report

Gowen Field, Idaho

34

ARNG will evaluate the need for an SI at AOI 1 at Gowen Field based on the potential receptors,

the potential migration of PFAS contamination off the facility, and the availability of resources.

ARNG and ANG will evaluate the need for an SI at AOI 2 and AOI 3 pending a decision on which

entity will conduct future investigations at these locations.
AOI 1

AOI 2

AOI 3

Fivemile Creek

Ridenbaugh Canal

New York Canal

ID ANG AFFF Dump 2

AASF ID ANG AFFF Dump 1

ID ANG Former FTA #1

ID ANG Hangars 1529 and 1530

Fire Station (Building 138)

ID ANG Hangar 148

ID ANG Hangar 155

2012 Plane Crash

ID ANG Former FTA #2

Central Drainage Ditch

City Burn Pit

Legend

Area of Interest

Potential PFAS Release

Facility Boundary

Water Body

River/Stream

Canal/Ditch

Underground Culvert

0 1,700 3,400 850

Feet

Summary of Findings

Figure 7-1

CLIENT

REVISED

SCALE

10/29/2019 MS

PD

10/29/2019

10/29/2019

ARNG

GIS BY

CHK BY

TITLE

PROJECT Preliminary Assessment for PFAS at Gowen Field, ID

Q:\Projects\ENV\GEARS\GEO\ARNG PFAS\900-CAD-GIS\920-GIS or Graphics\MXD\ID\Gowen_Figures\Fig_7-1_Gowen_Field_Summary.mxd

PM RG 10/29/2019

1:20,400 ­ 12420 Milestone Center Drive

Germantown, MD 20876

Base Map: Source: Esri, DigitalGlobe, GeoEye, Earthstar Geographics, CNES/Airbus

DS, USDA, USGS, AeroGRID, IGN, and the GIS User Community


PFAS Preliminary Assessment Report

Gowen Field, Idaho

36
PFAS Preliminary Assessment Report

Gowen Field, Idaho

37

8. References

CH2M Hill. 2015. Final Preliminary Assessment Report for Perfluorinated Compounds at Boise

Air National Guard Boise, Idaho. August.

HAZWRAP (Hazardous Waste Remedial Actions Program) 1994. Site Inspection Addendum,

Gowen Field, Boise Idaho, January.

Idaho Department of Water Resources (IDWR). 2019. Available at https://dataidwr.opendata.arcgis.com/pages/popular-maps (Accessed March 2019).

Idaho National Guard. 2019. Available at https://imd.idaho.gov/idaho-national-guard/our-history/

(Accessed March 2019).

Leidos. 2014. Preliminary Assessment/Site Inspection for Eleven Areas of Concern at Idaho Air

National Guard, Gowen Field, Boise, ID. May.

Leidos. 2019. Final Site Inspection Report for Perfluorooctane Sulfonate and Perfluorooctanoic

Acid at Gowen Field Boise, Idaho. February.

National Ground Water Association (NGWA). 2018. Groundwater and PFAS: State of

Knowledge and Practice. January.

National Oceanic and Atmospheric Administration. National Centers for Environmental

Information Data. Available at https://www.ncdc.noaa.gov/cdo-web/datatools/normals.

Accessed May 2019.

Othberg, Kurt L. 1994. Geology and Geomorphology of the Boise Valley and Adjoining Areas,

Western Snake River Plain, Idaho. January 1994.

Petrich, Christian R. 2004. Simulation of Ground Water Flow in the Lower Boise River Basin.

Idaho Water Resources Research Institute and Idaho Department of Water Resources.

February 2004. Available at https://idwr.idaho.gov/files/projects/treasure-valley/TVHPModel.pdf.

Petrich, Christian R. and Urban, Scott M. 2004. Characterization of Ground Water Flow in the

Lower Boise River Basin. Idaho water Resources Research Institute and Idaho Department

of Water Resources. February 2004. Available at

https://idwr.idaho.gov/files/projects/treasure-valley/TVHP-Characterization.pdf.

United States Environmental Protection Agency (USEPA). 1991. Guidance for Performing

Preliminary Assessments under CERCLA. September.

United States Census Bureau (USCB). 2017. www.census.gov.

U.S. Climate Data. 2019. Climate – Boise Idaho. Available at

https://www.usclimatedata.com/climate/boise/idaho/united-states/usid0463. Accessed August

2019.

Wood, Spencer H. and Clemens, Drew M. 2002. Geologic and Tectonic History of the Western

Snake River Plain, Idaho and Oregon. 2002.