B.08 GFI JB CHS PBR DA017 (SWMU 17) Draft UIC Permit App for Supplemental Injection redline2.pdf

DRAFT

UNDERGROUND INJECTION CONTROL PERMIT

APPLICATION FOR SUPPLEMENTAL INJECTION

PERFORMANCE-BASED REMEDIATION

Solid Waste Management Unit 17 (DA017) Joint Base Charleston Weapons

SOUTH CAROLINA

Contract FA8903-15-C-0016 December 2021January 2022

Revision 00

Prepared for:

AFCEC/CZRE

US Air Force Civil Engineer Center

772nd ESS/PKS 2261 Hughes Avenue, Suite 155 JBSA Lackland, TX 78236-9853

Prepared by:

AECOM

4016 Salt Pointe Parkway, Charleston, South Carolina 29405

With Teaming Partners:

Underground Injection Control Permit Application for Supplemental Injection

SWMU 17 (DA017)

Joint Base Charleston Weapons, South Carolina

Contract FA8903-15-C-0016 i BWJ140078

Table of Contents SCDHEC UIC Permit Application Form I Attachment A: Activity for Review Attachment B: Well Construction Details Attachment C: Operating Data Attachment D: Monitoring Program Attachment E: Existing or Pending State/Federal Permits Attachment F: Description of Business Attachment G: Area of Review Attachment H: Maps of Wells and Area of Review Attachment I: Cross Sections/Diagrams Attachment J: Names and Depth of Underground Sources of Drinking Water Attachment K: Hydraulic Control

List of Tables

Table 1 Injection Well Construction Details Table 2 Summary of Sampling Equipment Table 3 Summary of Sampling Events Table 4 Summary of Sampling Protocol Table 5 Monitoring Well Construction Details

List of Figures

Figure 1 SWMU 17 Injection Well Locations Figure 2 SWMU 17 Location Map Figure 3 SWMU 17 Supplemental Injection Area of Review Figure 4 SWMU 17 Topographic Map Figure 5 SWMU 17 Shallow Groundwater Contours - High Tide (October 2020) Figure 6 SWMU 17 Shallow Groundwater Contours - Low Tide (October 2020) Figure 7 SWMU 17 Deep Groundwater Contours - High Tide (October 2020) Figure 8 SWMU 17 Deep Groundwater Contours - Low Tide (October 2020) Figure 9 SWMU 17 Cross Section Location Map Figure 10 SWMU 17 Cross Section C-C’

Joint Base Charleston Weapons, South Carolina

Contract FA8903-15-C-0016 ii BWJ140078

Acronyms and Abbreviations AQ ................. aqueous bgs ................. below ground surface CaCO3 ........... calcium carbonate CMI ................ corrective measures implementation CT .................. carbon tetrachloride DCA ............... dichloroethane DCE ............... dichloroethene DHB ............... Dehalobacter DHC ............... dehalococcoides DO ................. dissolved oxygen EVO ............... emulsified vegetable oil ft .................... foot/feet gpm ................ gallons per minute GW ................ groundwater JBC ................ Joint Base Charleston MI................... Microbial Insights mL .................. milliliter MNA ............... monitored natural attenuation msl ................. mean sea level ORP ............... oxidation-reduction potential PCA ............... tetrachlorethane PCE ............... tetrachlorethene psi .................. pounds per square inch qPCR ............. quantitative polymerase chain reaction SCDHEC ........ South Carolina Department of Health and Environmental Control SOP ............... standard operating procedure SWMU ........... solid waste management unit TCA ............... trichloroethane TCE ............... trichloroethene TOC ............... total organic carbon UFP-QAPP .... Uniform Federal Policy – Quality Assurance Project Plan UIC ................ underground injection control USEPA .......... United States Environmental Protection Agency VC .................. vinyl chloride VOC ............... volatile organic compound ZVI ................ zero valent iron

Joint Base Charleston Weapons, South Carolina

Contract FA8903-15-C-0016 1 BWJ140078

SCDHEC UIC Permit Application Form I

Joint Base Charleston Weapons, South Carolina

Contract FA8903-15-C-0016 2 BWJ140078

Attachment A: Activity for Review

This Underground Injection Control (UIC) Permit Application is being submitted for a supplemental injection of emulsified vegetable oil (EVO), sodium bicarbonate, and zero valent iron (ZVI) at Solid Waste Management Unit (SWMU) 17, Joint Base Charleston (JBC) Weapons.

The objective of the injection is to stimulate bioremediation to remediate contaminated groundwater.

A previous pilot study consisting of direct injection of buffered EVO through standard Geoprobe® direct push technology rods was conducted from May 2004 through October 2007. The results of that pilot study demonstrated the effectiveness of the EVO for treatment of chlorinated volatile organic compounds in groundwater; however, the permeability of the shallow aquifer was reduced following the injection.

In order to prevent aquifer smearing and provide greater substrate distribution, another pilot study was conducted in early 2017 injecting through two permanent 2-inch diameter injection wells. In addition, sodium bicarbonate was used as the buffering agent in the second pilot study.

Sodium bicarbonate is relatively soluble, and therefore has the potential to react quickly. The post-injection pH in the aquifer remained neutral (between 6 and 7.5) throughout the pilot study, indicating that the sodium bicarbonate was successful in buffering the substrate. During the 2017 pilot study, the injection substrate was injected into the aquifer at a steady flow rate and minimal daylighting occurred. Although the post-injection slug test results indicated some impact to the aquifer permeability in the immediate vicinity of the injection wells, results from nearby monitoring wells 17MW05S and 17MW07S indicated that these impacts are limited in their extent. Groundwater elevations increased significantly from baseline directly following the injection but returned to baseline elevation by the fourth post-injection monitoring event. This indicates that the injections did not cause significant or prolonged aquifer plugging. These data suggested that the use of 2-inch diameter permanent injection wells minimized impacts to aquifer permeability and that they are suitable for remedy implementation. Therefore, 2-inch diameter injection wells and EVO buffered with sodium bicarbonate were proposed for the full-scale remediation (AECOM, 2016).

For the full-scale injection, 28 injection wells (17IW01-17IW28; Figure 1) with screened intervals from approximately 10 to 25 feet (ft) below ground surface (bgs) were installed. Approximately 1,249 pounds of SRS-SD (SRS - small droplet) EVO and approximately 539 pounds of sodium bicarbonate were injected into each of the 28 injection wells for a total of approximately 34,972 pounds of EVO and 15,092 pounds of sodium bicarbonate. The substrate was diluted with tap water and injected into the injection wells. Approximately 3,000 gallons of solution were injected into each injection well, followed by approximately 1,000 gallons of chase water. If daylighting occurred or the injection pressure increased substantially and the injection flow rate of substrate into a well decreased significantly, then injection into that well was stopped and injection hose was connected to the next injection well. If daylighting began or injection pressure increased significantly and injection flow rate decreased in a well prior to 1,000 gallons of chase water being injected, the chase water injection into that well was considered to be complete. A total of 103,050 gallons (82,708 gallons of substrate and a total of 20,302 gallons of chase water) were injected into the groundwater during the full-scale injection event (AECOM, 2018).

It is proposed that a supplemental injection event be conducted. The proposed supplemental injection event would include the injection of approximately 1,249 pounds of EVO (equivalent to three 55-gallon drums of SRS-SD), 539 pounds of sodium bicarbonate, and 270 pounds of ZVI injected into each of the following six injection wells: 7IW08, 17IW09, 17IW10, 17IW12, 17IW14, and 17IW17 (Figure 1). Therefore, for the supplemental injection event, a total of approximately

Joint Base Charleston Weapons, South Carolina

Contract FA8903-15-C-0016 3 BWJ140078

7,494 pounds of EVO, 3,234 pounds of sodium bicarbonate, and 1,620 pounds of ZVI will be injected. The proposed supplemental injection substrate is similar to the full-scale injection substrate with the addition of approximately 270 pounds of ZVI per injection well. In 2017, ZVI was used as an approved groundwater amendment at the site as part of the soil remediation activities (excavation of “hot spots”). Prior to backfilling, SRS®-Z (an EVO product containing ZVI) and sodium bicarbonate were added to the open excavations to stimulate additional reductive dechlorination in the groundwater beneath the “hot spots” (AECOM, 2018). For this supplemental injection event, similar to the full-scale injection event, the substrate will be diluted with tap water from a nearby fire hydrant. Substrate batches will be prepared 500 gallons at a time, with approximately 0.5 drum of EVO and 90 pounds of sodium bicarbonate, and 39 pounds of ZVI per batch. It is proposed that 3,000 gallons of solution followed by 1,000 gallons of chase water be injected into each of the six injection wells (total of 24,000 gallons injected into the groundwater).

Attachment B: Well Construction Details Six existing injection wells (Figure 1) will be used for the purpose of injecting aqueous suspensions of EVO, sodium bicarbonate, and ZVI. The construction details for existing injection wells to be used during this supplemental injection are provided on Table 1.

Table 1 Injection Well Construction Details

Well Number Ground

Elevation (ft msl)

Top of Riser Elevation (ft msl)

Screen Interval (ft bgs)

Top of Screen Elevation (ft msl)

Bottom of Screen Elevation (ft msl)

17IW08 10.98 14.03 10-25.5 0.98 -14.52

17IW09 9.98 13.73 10-25.5 -0.02 -15.52

17IW10 9.63 12.74 10-25.5 -0.37 -15.87

17IW12 11.01 14.24 10-25.5 1.01 -14.49

17IW14 9.73 12.92 10-25.5 -0.27 -15.77

17IW17 10.66 14.35 10-25.5 0.66 -14.84

Notes:

bgs – below ground surface ft – feet msl – mean sea level

Attachment C: Operating Data The fluid to be injected: Aqueous suspension of EVO, sodium bicarbonate, and ZVI Number of injection wells: Six injection wells

1) Average and maximum daily rate and volume to be injected:

The average injection rate for each injection well is anticipated to be approximately three gallons per minute (gpm). Injection is anticipated to occur for approximately 10 hours per day, resulting in an expected average daily rate of approximately 1,800 gallons per day per well. The maximum injection rate will be five gpm for a maximum daily rate of approximately 3,000 gallons per day per well.

Approximately 3,000 gallons of EVO, sodium bicarbonate, and ZVI solution and up to 1,000 gallons of potable water will be injected into each of six injection wells for the supplemental injection.

2) Average and maximum daily rate and volume of air/groundwater to be withdrawn from each recovery well:

Joint Base Charleston Weapons, South Carolina

Contract FA8903-15-C-0016 4 BWJ140078

No air or groundwater will be withdrawn from the injection wells.

3) Average and maximum injection pressure:

Average expected injection pressure: 10-25 pounds per square inch (psi); maximum:

90 psi.

4) Pumping schedule:

Continuous delivery of the EVO solution for approximately 10 hours per day is planned, until the planned volume has been injected. Field changes and adjustments to the planned delivery schedule may be required to improve the effectiveness of the proposed injection work.

5) Proposed ranges in the concentration of all contaminant constituents within the injection fluid:

None

6) Length of time the project is expected to require injection remediation:

It is anticipated that the supplemental injection would occur over a period of approximately one week.

Attachment D: Monitoring Program A groundwater monitoring event was conducted in April 2021 to serve as the injection baseline.

Following the supplemental injection, semi-annual corrective measures implementation (CMI) groundwater monitoring events will resume with the current sampling scheduled for the second and fourth quarter of each year. Groundwater samples will be collected from 12 monitoring wells during second quarter and 21 monitoring wells during fourth quarter, as previously approved in the CMI Progress Report 6 (AECOM, 2021).

Groundwater samples will be collected using a peristaltic pump attached to dedicated Teflon® tubing that will be eliminate the potential for cross-contamination. Low-flow purging and sampling methods will be utilized at the site in accordance with the Uniform Federal Policy – Quality Assurance Project Plan (UFP-QAPP) for Performance-Based Remediation Basewide Groundwater, Surface Water, and Land Use Control Monitoring, JBC Weapons and JBC Air (Bay West, 2016) and relevant United States Environmental Protection Agency (USEPA) standard operating procedures (SOPs). Field equipment is listed in Table 2.

Table 2 Summary of Sampling Equipment Equipment Required Calibration

Keck oil water interface probe, or equivalent X Peristaltic pump X YSI 556 water quality meter, or equivalent

- pH, specific conductivity, temperature, dissolved oxygen (DO), and oxidation-reduction potential (ORP)

X X

HF Scientific® DRT-15 turbidity meter, or equivalent X X DO – dissolved oxygen; ORP – oxidation-reduction potential

All groundwater samples collected during the semi-annual monitoring events will be submitted to Pace Analytical Gulf Coast, LLC, a South Carolina Department of Health and Environmental Control (SCDHEC)-certified laboratory. All groundwater samples collected during the monitoring events will be analyzed for the following:

Joint Base Charleston Weapons, South Carolina

Contract FA8903-15-C-0016 5 BWJ140078

Table 3 Summary of Sampling Events

Frequency Wells Analytes Analytical Methods

Second Quarter

17MW05S

17MW06S

17MW07S*

17MW19S

17MW20S

17MW42

17MW65

17MW66*

17MW67*

17MW68

17MW69

17-PS-2

Select VOCs

(1,1,2,2-PCA, 1,1,2-

TCA, 1,1-DCE, 1,2-

DCA, cis-DCE, CT, chloroform, methylene chloride, PCE, TCE, and VC);

MNA parameters (anions; dissolved gases [methane, ethane, and ethene];

Alkalinity as CaCO3;

TOC; sulfide; and orthophosphate);

and microbial (DHC & DHB, select locations*).

SW-846 8260B,

SW-846 9056A,

RSK-175,

SM 2320B,

SW-846 9060A,

SW-846 9030,

SM 4500P_E,

MI SOP qPCR

Fourth Quarter

17MW02S

17MW03S

17MW05S*

17MW06S

17MW07S*

17MW12S

17MW15S

17MW16S

17MW17S

17MW18S

17MW19S

17MW20S

17MW21S

17MW23S

17MW42

17MW65

17MW66*

17MW67*

17MW68

17MW69

17-PS-2

Select VOCs

(1,1,2,2-PCA, 1,1,2-

TCA, 1,1-DCE, 1,2-

DCA, cis-DCE, CT, chloroform, methylene chloride, PCE, TCE, and VC);

MNA parameters (anions; dissolved gases [methane, ethane, and ethene];

Alkalinity as CaCO3;

TOC; sulfide; and orthophosphate);

and microbial (DHC & DHB, select locations*).

SW-846 8260B,

SW-846 9056A,

RSK-175,

SM 2320B,

SW-846 9060A,

SW-846 9030,

SM 4500P_E,

MI SOP qPCR

Notes:

CaCO3 – calcium carbonate

CT – carbon tetrachloride DCA – dichloroethane DCE – dichloroethene DHB – dehalobacter DHC – Dehalococcoides MNA – monitored natural attenuation PCA – tetrachloroethane PCE- tetrachloroethene TCA – trichloroethane TCE – trichloroethene TOC – total organic carbon VC – vinyl chloride VOC – volatile organic compound MI SOP – Microbial Insights Standard Operating Procedure

Additionally, water quality parameters (pH, temperature, specific conductance, DO, and ORP) will be measured in the field and recorded during well purging activities. The sampling protocol, Joint Base Charleston Weapons, South Carolina

Contract FA8903-15-C-0016 6 BWJ140078 including the sample containers, sample volume, sample preservation, and sample holding times for each analytical method is presented in Table 4.

Table 4 Summary of Sampling Protocol

Matrix Analytical Group

USEPA

Analytical / Preparation Method SOP Reference

Containers (number, size, and type)

Preservation Requirements

(chemical, temperature, light protected)

Maximum Holding Time (preparation / analysis)

AQ VOCs

SW-846

5030B/8260B

GCMSV-003

3 x 40 milliliters

(mL) VOC vial

Cool, ≤6°C, hydrochloric acid, pH<2, no headspace

14 days

AQ Anions SW-846 9056A

WL-042

1 x 250 poly bottle Cool, ≤6°C 28 days

AQ Dissolved Gases

RSK-175

GCV-024

2 x 40 mL VOC vial

Cool, ≤6°C, No headspace 14 days

AQ TOC SW-846 9060A

WL-043

2 x 40 mL VOC vial

Cool, ≤6°C, pH <2 28 days

AQ Alkalinity SW-846 2320B/

WL-063

1 x 250 poly bottle Cool, ≤6°C 14 days

AQ Sulfide

SW 9034

1 x 125 poly bottle

Cool, ≤6°C, Zinc Acetate, NaOH, pH>9 7 days

AQ Ortho-phosphate

SM 4500P_E

WL-048

1 x 1000 poly bottle Cool, ≤6°C 48 Hours

GW MICRO MI SOP qPCR 1 liter poly or Bio-flo filter (4±2) °C 24-48 hours

Notes:

°C – degrees Celsius mL – milliliter qPCR – quantitative polymerase chain reaction SOP – standard operating procedure TOC – top of casing VOC – volatile organic compound AQ – Aqueous GW - Groundwater

Attachment E: Existing or Pending State/Federal Permits The work at JBC Weapons will be conducted under Resource Conservation and Recovery Act Part B permit number SC8 170 022 620, effective 22 September 2011 through 22 September 2021 (renewal pending). SCDHEC is the primary regulatory contact. Prior to injection activities and as standard practice, SCDHEC will issue a UIC Permit to Operate.

Attachment F: Description of Business JBC Weapons is located 10 miles north of Charleston, South Carolina, approximately 16 miles inland from the Atlantic Ocean. The facility is situated in two counties, Berkeley and Charleston, and occupies 16,868 acres. The eastern section of the facility is bordered by the Cooper River and the Back River; the western section is bordered by the CSX Railroad. The facility, formerly Naval Weapons Station Charleston, has been under Air Force direction since October 1, 2010, and is referred to as JBC Weapons.

Joint Base Charleston Weapons, South Carolina

Contract FA8903-15-C-0016 7 BWJ140078

JBC Weapons is divided into three sections: the northernmost section (referred to as Northside and formerly referred to as the Polaris Missile Facility Atlantic Fleet Area), the central section (referred to as Southside), and the southernmost section (referred to as the South Annex). The areas are collectively referred to as JBC Weapons.

SWMU 17 is located in the southern part of JBC Weapons (Figure 2), immediately east and across Wilkinson Way from SWMU 16 (Figure 1). SWMU 17 is generally rectangular (approximately 500 ft long and 200 ft wide) and covers approximately 2.1 acres. The site was used primarily for surface disposal of solid waste between 1950 and 1978, but oils and missile components were also disposed at the site. An estimated 3,000 to 4,000 gallons of engine oil were disposed of at SWMU 17 between 1965 and 1966, and a thorium-alloy missile nose cone exhibiting low level radioactivity was removed from the site in 1984.

Attachment G: Area of Review The supplemental injection area of review, shown in Figure 3, includes the area ¼-mile around the injection area.

Attachment H: Maps of Wells and Area of Review

1) A topographic map extending one mile beyond the property boundaries is attached as Figure 4. There is no hazardous waste treatment, storage, or disposal facility associated with SWMU 17. Areas of known soil and/or groundwater contamination (SWMUs) within a one-mile radius of SWMU 17 are also shown on Figure 4. SWMU 17 existing injection well locations are provided on Figure 1.

2) All monitoring wells within the area of review are shown on Figure 3. There are no existing production wells or abandoned and dry wells within the area of review. The well construction details for the monitoring wells at SMWU 16 and SMWU 17 are provided in Table 5.

3) Potentiometric maps of the shallow and deep aquifers at high and low tide at SWMU 17 in October 2020 are provided in Figures 5 through 8. Site wells were separated into shallow unconfined aquifer wells and deep unconfined aquifer wells based on a minor lithologic transition (AGVIQ-CH2MHILL, 2010). Shallow aquifer wells are screened between approximately -16 to +1 ft mean sea level (approximately 4 to 20 ft bgs). Deep aquifer wells are screened between approximately -38 to -9 ft mean sea level (approximately 15 to 42 ft bgs).

Table 5 Monitoring Well Construction Details

Well Number Ground

Elevation (ft msl)

Top of Riser Elevation (ft msl)

Screen Interval (ft bgs)

Top of Screen Elevation (ft msl)

Bottom of Screen Elevation (ft msl)

16MW01S 4.89 7.83 4-14 0.89 -9.11

16MW02S 0.65 4.91 3-13 -2.35 -12.35

16MW03S 2.08 4.92 3-13 -0.92 -10.92

16MW04S 1.51 4.39 3-13 -1.49 -11.49

16MW05S 1.63 4.61 3-13 -1.37 -11.37

17MW01S 7.23 10.51 4-14 3.23 -6.77

17MW02S 4.56 7.72 5-15 -0.44 -10.44

17MW03SR 6.04 8.74 5-15 1.04 -8.96

17MW04S 4.39 7.20 5-15 -0.61 -10.61

17MW05S 5.31 7.83 8-18 -2.69 -12.69

17MW06D 5.37 7.69 18-23 -12.63 -17.63

Joint Base Charleston Weapons, South Carolina

Contract FA8903-15-C-0016 8 BWJ140078

Well Number Ground

Elevation (ft msl)

Top of Riser Elevation (ft msl)

Screen Interval (ft bgs)

Top of Screen Elevation (ft msl)

Bottom of Screen Elevation (ft msl)

17MW06S 5.49 7.95 8-18 -2.51 -12.51

17MW07S 5.44 7.99 8-18 -2.56 -12.56

17MW11S 7.36 9.78 10-20 -2.64 -12.64

17MW12D 5.38 7.30 18-28 -12.62 -22.62

17MW12S 5.41 7.48 4-14 1.41 -8.59

17MW13S 5.39 7.56 4-14 1.39 -8.61

17MW14D 4.05 6.66 15-25 -10.95 -20.95

17MW14S 3.95 6.27 4-14 -0.05 -10.05

17MW15D 3.45 5.92 29-39 -25.55 -35.55

17MW15S 3.76 6.01 10-20 -6.24 -16.24

17MW16D 3.48 5.92 32-42 -28.52 -38.52

17MW16I 3.66 6.05 15-25 -11.34 -21.34

17MW16S 3.52 5.83 5-15 -1.48 -11.48

17MW17D 3.52 6.00 27-37 -23.48 -33.48

17MW17I 3.42 6.07 13-23 -9.58 -19.58

17MW17S 3.37 6.19 4-14 -0.63 -10.63

17MW18D 3.59 5.48 15-22 -11.41 -18.41

17MW18S 3.76 5.41 4-14 -0.24 -10.24

17MW19S 5.50 7.81 8-18 -2.50 -12.50

17MW20S 4.89 7.38 4-14 0.89 -9.11

17MW21S 7.99 10.47 8-18 -0.01 -10.01

17MW22S 7.77 10.28 10-20 -2.23 -12.23

17MW23S 4.76 7.18 9-19 -4.24 -14.24

17MW36 5.10 7.72 15-25 -9.90 -19.90

17MW42 5.00 7.62 15-25 -10.00 -20.00

17MW65 4.74 7.59 15-25 -10.26 -20.26

17MW66 6.53 9.17 15-25 -9.47 -19.47

17MW67 6.00 8.82 15-25 -9.00 -19.00

17MW68 5.10 7.68 15-25 -9.99 -19.99

17MW69 4.44 7.32 15-25 -10.56 -20.56

Notes:

bgs – below ground surface ft – feet msl – mean sea level

Attachment I: Cross Sections/Diagrams The location of the geologic cross section of SWMU 17 is shown in Figure 9 and a geologic cross section through the portion of the site where injection wells were installed is shown on Figure 10 (AGVIQ-CH2MHILL, 2010). This cross section shows the site prior to injection well installation.

The lithology of the surficial aquifer beneath the site consists of a clay unit at the ground surface to about 5 to 10 ft bgs. Beneath the clay unit is a silt and sand unit that coarsens downward to a shelly sand unit with a combined thickness of 17 to 32 ft. Beneath the shelly sand in the western portion of the site is a distinct silt and clay unit. The silt and clay unit changes laterally into a sand unit that extends from the central portion of the site to beyond the eastern boundary. A thick, low-permeability silt/clay unit underlies both the silt and clay unit and the sand unit, sloping from 16 ft bgs in the northern half of the site, to 42 ft bgs in the southern half of the site

(AGVIQ-CH2MHILL, 2010).

Joint Base Charleston Weapons, South Carolina

Contract FA8903-15-C-0016 9 BWJ140078

The surficial aquifer beneath the site displays the characteristics of an unconfined to semi-confined system. Typically, the groundwater is encountered just beneath the upper clay unit which occurs between 5 and 12 ft bgs; however, upon monitoring well completion, the static water level equilibrates at levels of approximately 3 to 6 ft bgs. Groundwater flows east toward the tributary of Goose Creek and is tidally influenced.

Attachment J: Names and Depth of Underground Sources of Drinking Water No underground sources of drinking water will be affected by the EVO injection solution. EVO will be injected in the deeper portion of the surficial aquifer (Ladson Formation).

Attachment K: Hydraulic Control The average hydraulic gradient at SWMU 17 is 0.0074 ft/ft, calculated from the November 2017 baseline gauging event. The geometric average hydraulic conductivity was calculated to be approximately 1.39 ft/day (i.e., 4.91 × 10-4 centimeters per second) from the pre-injection slug tests performed in October 2017. The effective porosity of the upper surficial aquifer is estimated to be 0.30. The average seepage velocity (groundwater flow velocity) is calculated to be 0.034 ft/day (i.e., 12.41 ft/year).

Joint Base Charleston Weapons, South Carolina

Contract FA8903-15-C-0016 10 BWJ140078

REFERENCES

AECOM, 2016. Uniform Federal Policy – Quality Assurance Project Plan and Corrective

Measures Implementation Work Plan, SWMU 17, Joint Base Charleston - Weapons, Charleston, South Carolina. April.

AECOM, 2018. Draft Final Construction Completion Report for SWMU 17, Joint Base

Charleston Weapons, Charleston, South Carolina. August.

AECOM, 2021. Draft Final Semi-Annual Corrective Measures Implementation Progress Report

#6 for SWMU 17, Joint Base Charleston Weapons, Charleston, South Carolina. May.

AGVIQ-CH2MHILL, Joint Venture, 2010. Technical Memorandum: Optimization of Soil and

Groundwater Remedy at SWMU 17, Naval Weapons Station Charleston, Charleston, South Carolina. October.

Bay West, 2016. Uniform Federal Policy - Quality Assurance Plan for Performance-Based

Remediation Basewide Groundwater, Surface Water, and Land Use Control Monitoring, Joint Base Charleston Weapons and Joint Base Charleston Air, South Carolina.

December.

SCDHEC, 2012. Conditional Approval, SWMU 16 and 17 RTCs and Final Corrective Measures

Study, Joint Base Charleston Weapons, SC8 170 022 620. June.

Joint Base Charleston Weapons, South Carolina

Contract FA8903-15-C-0016 BWJ140078

FIGURES

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17IW04

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17IW09

17IW10 17IW11

17IW12

17IW13

17IW14

17IW15

17IW16

17IW17

17IW18

17IW19 17IW20

17IW21 17IW22

17IW23

17IW24 17IW25 17IW26

17IW27 17IW28

17IW01

17IW02

Figure 1

SWMU 17

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Figure 2

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SWMU 17

Joint Base Charleston- Weapons Boundary

60214949

Site Location

GA

SC

NC

0 90 18045 Miles

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17MW23S

17MW21S

17MW20S

17MW19S

17MW18S

17MW17S

17MW16S

17MW15S

17MW07S

17MW06S

17MW05S

17MW04S

17MW03S 17MW02S

17-PS-217IW02

17IW01

17-PS-7

17-PS-6

17-PS-517-PS-4

16MW05S

16MW04S

16MW03S

16MW02S

SWMU 17

SWMU 17

SWMU 51

SWMU 18

SWMU 16

AOC-L

Figure 3

SWMU 17

Pilot Study Area of Review

Drawn By: Date Drawn/Revised: Project No.

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A re a of

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0 200 400100 Feet

0 80 16040 Meters µ Joint Base Charleston Weapons Charleston, South Carolina

!A Proposed Injection Well

!. Proposed Temporary Monitoring Well

@A Existing Monitoring Well

!A New Injection Well

Groundwater Target Treatment Zone (TTZ)

Current SWMU 17 Boundary

Original Site Boundary

SWMU 16 & 17 LUC Boundary

Area of Review (1/4 Mile)

AOC-L

SWMU 51

SWMU 18

SWMU 16

Depression Area

(R-1/19/2022)LLM 60444074

Note:

Current SWMU 17 Boundary based on 2012 Annual Monitoring Report, SWMU 17, March 2014, TEC-BSC Joint Venture.

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W ilk in so n W ay

17MW02s

17MW03s

17MW05s

17MW06d 17MW06s

17MW07s

17MW11s

17MW12d

17MW12s

17MW16d 17MW16i

17MW16s

17MW17d

17MW17i

17MW17s

17MW18d

17MW18s

17MW19s

17MW20s

17MW23s

17MW36

17MW42

17MW65

17MW66

17MW67

17MW68

17MW69

17MW22s

Service Layer Credits: Source: Esri, Maxar, GeoEye, Earthstar Geographics, CNES/Airbus DS, USDA, USGS, AeroGRID, IGN, and the GIS User Community Enlargement

See Enlargement

0 100 20050 Feetµ

SWMU 81

AOC L

SWMU 17

SWMU 83

SWMU 68

SWMU 67

SWMU 79

SWMU 80

AOC O

AOC N

SWMU 25

SWMU 23

SWMU 40

SWMU 16

SWMU 18

SWMU 22

SWMU 20

SWMU 29

SWMU 28

Copyright:© 2013 National Geographic Society, i-cubed

Figure 4

SWMU 17

Topographic Map

Drawn By: Date Drawn/Revised: Project No.12/28/2021

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CSB

0 3,000 6,0001,500 Feet

0 1,000 2,000500 Meters µ Joint Base Charleston Weapons Charleston, South Carolina

1 Mile Radius

Joint Base Charleston- Weapons Boundary

SWMU/AOC Location

60214949

Basemap Source: Esri World Imagery http://services.arcgisonline.com/arcgis/services/World_Imagery

© 2011 Esri, i-cubed, USDA FSA, USGS, AEX, GeoEye, AeroGRID, Getmapping, IGP

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17-PS-4

(NM)

17-PS-6

(NM)

17MW02S

(4.59)

17MW03S

(4.19)

17MW04S

(NM)

17MW05S

(4.19)

17MW06S

(4.21)

17MW07S

(4.21)

17MW11S

(4.29)

17MW12S

(4.25)

17MW13S

(NM)

17MW14S

(3.77)

17MW15S

(3.75)

17MW16S

(3.65)

17MW17S

(3.77)

17MW18S

(3.67)

17MW19S

(4.17)

17MW20S

(4.07)

17MW21S

(4.29)

17MW23S

(4.29)

17-PS-1

(NM)

17-PS-2

(4.23)

17-PS-3

(NM)

17MW22s

(NM)

4.3

4.5

3.6

3.7

4.4

3.8 3.94

4.1

4.3

4.2

Figure 5

SWMU 17

Shallow Groundwater Contours - High Tide

(October 2020)

Drawn By: Date Drawn/Revised: Project No.

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-H -.m xd

0 50 10025 Feet

0 20 4010 Meters µ Joint Base Charleston Weapons Charleston, South Carolina

@A Shallow Monitoring Well

@A Intermediate Monitoring Well

@A Deep Monitoring Well !. Deep Temporary Monitoring Well

Potentiometric Contour - 10/2020 Current SWMU 17 Boundary Former Depression Area

(R-9/23/2021)LLM 60444074

(3.10)

(NM) Not Measured Groundwater Flow Direction

Groundwater Elevation feet above mean sea level

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17-PS-4

(NM)

17-PS-6

(NM)

17MW02S

(4.40)

17MW03S

(4.20)

17MW04S

(NM)

17MW05S

(4.12)

17MW06S

(4.13)

17MW07S

(4.13)

17MW11S

(4.53)

17MW12S

(4.25)

17MW13S

(NM)

17MW14S

(3.73)

17MW15S

(3.69)

17MW16S

(3.98)

17MW17S

(4.05)

17MW18S

(4.07)

17MW19S

(4.17)

17MW20S

(4.11)

17MW21S

(4.21)

17MW23S

(4.26)

17-PS-1

(NM)

17-PS-2

(3.68)

17-PS-3

(NM)

17MW22s

(NM)

3.7

4.5

3.7 3.8

4.4

3.9

4.3 3.8 4.3

3.9

4.1 4.2

Figure 6

SWMU 17

Shallow Groundwater Contours - Low Tide

(October 2020)

Drawn By: Date Drawn/Revised: Project No.

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0 50 10025 Feet

0 20 4010 Meters µ Joint Base Charleston Weapons Charleston, South Carolina

@A Shallow Monitoring Well

@A Intermediate Monitoring Well

@A Deep Monitoring Well !. Deep Temporary Monitoring Well

Potentiometric Contour - 05/2020 Current SWMU 17 Boundary Former Depression Area

(R-9/23/2021)LLM 60444074

Groundwater Flow Direction

(3.10)

(NM) Not Measured

W ilk in so n W ay

17MW06D

(4.14)

17MW66

(4.07)

17MW12D

(3.70)

17MW14D

(3.48)

17MW15D

(3.69)

17MW16D

(NM)

17MW17D

(3.53)

17MW18D

(3.52)

17MW36

(3.96)

17MW42

(3.87)

17MW65

(3.77)

17MW67

(4.17)

17MW68

(3.85)

17MW69

(3.99)

17-PS-4

(NM)

17-PS-5

(NM)

17-PS-6

(NM)

17-PS-7

(NM)

4.0

3.9

3.8

3.7 3.6

4.1

3.8

3.9

3.8 3.5

Figure 7

SWMU 17

Deep Groundwater Contours - High Tide

(October 2020)

Drawn By: Date Drawn/Revised: Project No.

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.m xd

0 40 8020 Feet

0 10 205 Meters µ Joint Base Charleston Weapons Charleston, South Carolina

Potentiometric Contour - 10/2020 Current SWMU 17 Boundary Former Depression Area

(R-9/23/2021)LLM 60444074

Groundwater Flow Direction

(2.91)

(NM) Not Measured

W ilk in so n W ay

17MW06D

(4.02)

17MW66

(3.89)

17MW12D

(4.42)

17MW14D

(3.73)

17MW15D

(3.80)

17MW16D

(NM)

17MW17D

(3.82)

17MW18D

(3.74)

17MW36

(4.40)

17MW42

(3.84)

17MW65

(3.77)

17MW67

(4.04)

17MW68

(3.59)

17MW69

(4.01)

17-PS-4

(NM)

17-PS-5

(NM)

17-PS-6

(NM)

17-PS-7

(NM)

4.4

4.3 4.2

4.1

4.0

3.9

3.8 3.7

Figure 8

SWMU 17

Deep Groundwater Contours - Low Tide

(October 2020)

Drawn By: Date Drawn/Revised: Project No.

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0 40 8020 Feet

0 10 205 Meters µ Joint Base Charleston Weapons Charleston, South Carolina

@A Shallow Monitoring Well

@A Intermediate Monitoring Well

@A Deep Monitoring Well !. Deep Temporary Monitoring Well

Potentiometric Contour - 10/2020 Current SWMU 17 Boundary Former Depression Area

(R-9/23/2021)LLM 60444074

Groundwater Flow Direction

(2.91) (NM) Not Measured

Reference:

CH2MHILL

Figure 9

SWMU 17

Cross Section Location Map

Drawn By: Date Drawn/Revised: Project No.12/28/2021

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CSB

0 20 4010 Meters µ Joint Base Charleston Weapons Charleston, South Carolina

60214949

0 50 10025 Feet

!H

Monitoring Well

Temporary Well

MIP/TW

Figure 10

SWMU 17

Cross Section C-C'

Drawn By: Date Drawn/Revised: Project No.9/23/2021

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0 10 205 Meters µ Joint Base Charleston Weapons Charleston, South Carolina

60214949

0 20 4010 Feet

Reference:

CH2MHILL

Figure 2-2b Optimization Plan for Implementation of Groundwater Remedy at SWMU17