Ft. Drum Wells Field Final D-B RFP - Appendix C - Volume 3.pdf

Appendix C Vol. 3

HRGS Borehole Geophysical Logging – Data Report

HAGER-RICHTER GEOSCIENCE

Atkinson, NH & Fords, NJ

BOREHOLE GEOPHYSICAL LOGGING – DATA REPORT

FORT DRUM ERCIP WELL FIELD EXPANSION PROJECT

FORT DRUM ARMY AIRBASE, NEW YORK

Prepared for:

Arcadis U.S., Inc One Lincoln Center, 110 West Fayette Street Syracuse, New York 13202

Prepared by:

Hager-Richter Geoscience, dba HR Geological Services in New York 2 Industrial Way S/2 846 Main Street Atkinson, New Hampshire 03811 Fords, New Jersey 08863

Robert L. Garfield, P.G. (NY 000041) Owner / Principal Borehole Geophysicist

File 24RG60 January 2025

© 2025 Hager-Richter Geoscience, Inc., dba HR Geological Services in New York

HRGS

GEOPHYSICS FOR THE ENGINEERING & ENVIRONMENTAL COMMUNIITIES

2 Industrial Way S/2, Atkinson, NH 03811 (603.893.9944) 846 Main Street, Fords, NJ 08863 (732.661.0555) www.hager-richter.com

HAGER-RICHTER GEOSCIENCE, INC.

Atkinson, NH & Fords, NJ

January 7, 2025 File 24RG60

Suzie Bower Arcadis U.S., Inc One Lincoln Center 110 West Fayette Street Syracuse, New York 13202

Tel: 315.671.9147 Mob: 315.569.1663 Email: Suzie.Bower@arcadis.com

RE: Borehole Geophysical Logging Fort Drum ERCIP Well Field Expansion Project Fort Drum Army Airbase, New York

Dear Ms. Bower:

Hager Richter Geoscience, dba HR Geological Services in New York, (HRGS) is pleased to submit this data report to Arcadis U.S., Inc for borehole geophysical logging services provided in support of the Fort Drum ERCIP Well Field Expansion Project at the Fort Drum Army Airbase in New York.

BOREHOLE GEOPHYSICAL LOGGING SCOPE OF WORK

Borehole geophysical logging was conducted December 17-19, 2024, in the following seven (7) boreholes for the Fort Drum ERCIP Well Field Expansion Project at the Fort Drum Army Airbase in New York.

• A4-OBS-01D • A4-OBS-14

• A4-OBS-11 • Well-3R

• A4-OBS-12 • Well-4R

• A4-OBS-13

The borehole geophysical logging program consisted of the following in each of the logged boreholes. At the time of the borehole geophysical logging field work, each borehole was cased with 4-inch steel casing through the overburden and unstable shallow bedrock, and each borehole had 3.8-inch diameter open bedrock below the casing available for the borehole geophysical logging.

• Optical Televiewer (OTV)

• Acoustic Televiewer (ATV)

• Caliper

• Fluid Temperature

• Fluid Conductivity

• Heat Pulse Flow Meter (HPFM) Under Ambient Conditions

Borehole Geophysical Logging Fort Drum ERCIP Well Field Expansion Project Fort Drum Army Airbase, New York File 24RG60 January 2025

HRGS

EXPLANATION OF THE BOREHOLE GEOPHYSICAL DATA INTERPRETATION AND PRESENTATION

The datum for depths in this report is the top of the steel casing of each borehole. The optical televiewer (OTV) data and acoustic televiewer (ATV) data are referenced to true north using a magnetic declination of 12° west. The data report consists of the following.

Borehole Geophysical Logging Figure – The borehole geophysical logging figure is meant to be printed on standard portrait 8.5-inch x 11-inch paper and consists of the following.

Figure 1. Televiewer explanation figure o Borehole Geophysical Logs – The borehole geophysical logs are provided at a scale of 1-inch to 2-feet, are meant to be printed on 11-inch-wide paper, and consist of the following.

Track # Log & Description

1. OTV Image

2. Depth

3. ATV Amplitude

4. ATV Travel Time

5. Caliper – borehole diameter in inches

6. Fluid Temperature & Fluid Conductivity

7. Depth

8. HPFM Under Ambient Conditions

Borehole Flow Interpretation o Summary of Borehole Flow Tables – The borehole flow tables summarize the borehole flow conditions in each borehole individually, are meant to be printed on standard portrait 8.5-inch x 11-inch paper, and consists of the following.

Column # Description

1. Depth

2. Comments o Borehole Conditions/Construction o Borehole Flow Interpretation

BOREHOLE GEOPHYSICAL LOGGING RESULTS

Summary of Borehole Flow. The borehole flow interpretation is based primarily on the HPFM data acquired under ambient conditions along the with fluid properties (temperature and conductivity) and the presence of open bedrock fractures evident in the borehole televiewer (OTV and ATV) data. The tables provided in this data report summarize the borehole flow condition in each borehole at the time of logging, specifically the approximate depths and rates where flow was detected with the HPFM into and out of the boreholes from hydraulically transmissive bedrock fractures under ambient conditions.

Fort Drum Army Airbase, New York File 24RG60 January 2025

LIMITATIONS ON USE OF THIS REPORT

This data report was prepared for the exclusive use of Arcadis U.S., Inc. No other party shall be entitled to rely on this Report, or any information, documents, records, data, interpretations, advice, or opinions given to Client by Hager Richter Geoscience, dba HR Geological Services in New York, (HRGS) in the performance of its work. The report relates solely to the specific project for which HRGS has been retained and shall not be used or relied upon by Client or any third party for any variation or extension of this project, any other project, or any other purpose without the express written permission of HRGS.

Any unpermitted use by Client or any third party shall be at Client's or such third party's own risk and without any liability to HRGS.

HRGS has used reasonable care, skill, competence, and judgment in the performance of its services for this project consistent with professional standards for those providing similar services at the same time, in the same locale, and under like circumstances. Unless otherwise stated, the work performed by HRGS should be understood to be exploratory and interpretational in character and any results, findings or recommendations contained in this report or resulting from the work proposed may include decisions which are judgmental in nature and not necessarily based solely on pure science or engineering. It should be noted that our interpretations may be modified if additional information is provided to HRGS.

Except as expressly provided in this Limitations section, HRGS makes no other representation or warranty of any kind whatsoever, oral or written, expressed or implied; and all implied warranties of merchantability and fitness for a particular purpose, are hereby disclaimed.

If you have any questions or comments on this data report, please contact us at your convenience. It has been a pleasure to work with Arcadis U.S., Inc. on this project. We look forward to working with you again in the future.

Sincerely, HAGER-RICHTER GEOSCIENCE, INC.

Robert L. Garfield, P.G.

Owner / Principal Borehole Geophysicist

Fort Drum Army Airbase, New York File 24RG60 January 2025

BOREHOLE GEOPHYSICAL LOGGING FIGURE

Figure 1. Televiewer explanation. The image on the left depicts a planar structure in red, such as a fracture or bedding plane, intersected by a borehole. The image on the right depicts the same structure unwrapped as it would be displayed in an optical televiewer (OTV) or acoustic televiewer (ATV) log.

Figure modified from: Garfield, R.L., Day-Lewis, F.D., Gray, M.B., Johnson, C.D., Williams, J.H. and Day-Lewis, A.D.F., 2003, Fractured-Rock Aquifer Characterization within a Regional Geologic Context:

Results from the Bucknell University Hydrogeophysics Test Site, GSA Northeastern Section, 38th Annual Meeting, Paper No. 25-19.

HRGS

Atkinson, NH & Fords, NJ

Fort Drum Army Airbase, New York File 24RG60 January 2025

BOREHOLE GEOPHYSICAL LOGS

LOG DATUM:

BOREHOLE DIAMETER:

TOP OF CASING:

LOGS PROCESSED BY:

PROJECT REP(S) ON-SITE:

DATE(S) LOGGED:

PROJECT:

LOCATION:

LOGGING GEOPHYSICIST(S): ORIENTATION REFERENCE:

WATER LEVEL DEPTH:

HRGS FILE:CLIENT:

HRGS

dba HR Geological Services in New York

3.8 Inches (HQ-Cored)

Top of the 4-Inch Steel Casing

A4-OBS-01D - BOREHOLE GEOPHYSICAL LOGSAtkinson, NH (603.893.9944) Fords, NJ (732.661.0555) www.hager-richter.com

True North (Magnetic Declination = 12° West)

Josh Miller

Robert Garfield, P.G. & Nick DeCristofaro

December 17 & 19, 2024

Nick DeCristofaro & Vanja Dezelic

24RG60

4.9 Feet

3.0 Feet Above the Ground Surface

ARCADIS U.S.

Fort Drum ERCIP Well Field Expansion Project

Fort Drum Army Airbase, New York

A4-OBS-01D - Borehole Geophysical Logs

Depth

(Feet)

Depth

(Feet)

ATV Amplitude

0° 0°180°90° 270°

ATV Travel Time

0° 0°180°90° 270°

OTV Image

0° 0°180°90° 270°

Caliper

3 6(Inches)

Heat Pulse Flow Meter Under Ambient Conditions

-2 2(gpm)

Fluid Temperature

8 11(Degrees C)

Fluid Conductivity

250 1000(uS/cm) Negative = Flow Down Positive = Flow Up

Bottom of Casing flow into & down the borehole flow out of the borehole possible minor flow into or out of the borehole based on the fluid cond data no flow detected below ~47 feet with the HPFM no flow detected in the casing no flow detected flow dow n the borehole at~1 gpm

TOP OF CASING:

LOGS PROCESSED BY:

PROJECT REP(S) ON-SITE:

DATE(S) LOGGED:

PROJECT:

LOCATION:

LOGGING GEOPHYSICIST(S): ORIENTATION REFERENCE:

WATER LEVEL DEPTH:

HRGS FILE:CLIENT:

HRGS

dba HR Geological Services in New York

3.8 Inches (HQ-Cored)

Top of the 4-Inch Steel Casing

A4-OBS-11 - BOREHOLE GEOPHYSICAL LOGSAtkinson, NH (603.893.9944) Fords, NJ (732.661.0555) www.hager-richter.com

True North (Magnetic Declination = 12° West)

Josh Miller

Robert Garfield, P.G. & Nick DeCristofaro

December 18 & 19, 2024

Fort Drum ERCIP Well Field Expansion Project

Nick DeCristofaro & Vanja Dezelic

Fort Drum Army Airbase, New York

24RG60

12.6 Feet

2.9 Feet Above the Ground Surface

ARCADIS U.S.

A4-OBS-11 - Borehole Geophysical Logs

Depth

(Feet)

Depth

(Feet)

ATV Amplitude

0° 0°180°90° 270°

ATV Travel Time

0° 0°180°90° 270°

OTV Image

0° 0°180°90° 270°

Caliper

3 6(Inches)

Heat Pulse Flow Meter Under Ambient Conditions

-2 2(gpm)

Fluid Temperature

9 10.5(Degrees C)

Fluid Conductivity

700 1900(uS/cm) Negative = Flow Down Positive = Flow Up

Bottom of Casing flow into & down the borehole flow out of the borehole no flow detected below ~64.5 feet no flow detected in the casing no flow detected flow dow n the borehole at~1

TOP OF CASING:

LOGS PROCESSED BY:

PROJECT REP(S) ON-SITE:

DATE(S) LOGGED:

PROJECT:

LOCATION:

LOGGING GEOPHYSICIST(S): ORIENTATION REFERENCE:

WATER LEVEL DEPTH:

HRGS FILE:CLIENT:

HRGS

dba HR Geological Services in New York

A4-OBS-12 - BOREHOLE GEOPHYSICAL LOGS

Top of the 4-Inch Steel Casing

3.8 Inches (HQ-Cored)

Atkinson, NH (603.893.9944) Fords, NJ (732.661.0555) www.hager-richter.com

True North (Magnetic Declination = 12° West)

Robert Garfield, P.G. & Nick DeCristofaro

Josh Miller

December 18, 2024

Fort Drum ERCIP Well Field Expansion Project

Fort Drum Army Airbase, New York

Nick DeCristofaro & Vanja Dezelic

35.5 Feet

24RG60

2.9 Feet Above the Ground Surface

ARCADIS U.S.

NOTES: Acoustic caliper data can only be acquired in the water-filled portion of the borehole. The caliper data plotted in the logs below are 3-arm caliper data in the air-filled portion of the borehole and acoustic caliper data in the water-filled portion of the borehole.

A4-OBS-12 - Borehole Geophysical Logs

Depth

(Feet)

Depth

(Feet)

ATV Amplitude

0° 0°180°90° 270°

ATV Travel Time

0° 0°180°90° 270°

OTV Image

0° 0°180°90° 270°

Caliper

3 6(Inches)

Heat Pulse Flow Meter Under Ambient Conditions

-2 2(gpm)

Fluid Temperature

8.1 8.7(Degrees C)

Fluid Conductivity

250 550(uS/cm) Negative = Flow Down Positive = Flow Up no ATV, fluid conductivity, fluid temperature, and HPFM data above the water

Bottom of Casing

Water Level minor flow into & down the borehole flow into & down the borehole possible minor flow into or out of the borehole based on staining evident in the OTV image flow out of the borehole minor flow out of the borehole possible minor flow into or out of the borehole based on the fluid cond data no flow detected below ~58 feet with the HPFM no flow detected flow dow n at 0.03 gpm flow dow n the borehole at~1 gpm flow dow n the borehole at~1 gpm flow dow n

0.02

TOP OF CASING:

LOGS PROCESSED BY:

PROJECT REP(S) ON-SITE:

DATE(S) LOGGED:

PROJECT:

LOCATION:

LOGGING GEOPHYSICIST(S): ORIENTATION REFERENCE:

WATER LEVEL DEPTH:

HRGS FILE:CLIENT:

HRGS

dba HR Geological Services in New York

3.8 Inches (HQ-Cored)

Top of the 4-Inch Steel Casing

A4-OBS-13 - BOREHOLE GEOPHYSICAL LOGSAtkinson, NH (603.893.9944) Fords, NJ (732.661.0555) www.hager-richter.com

True North (Magnetic Declination = 12° West)

Josh Miller

Robert Garfield, P.G. & Nick DeCristofaro

December 17 & 18, 2024

Fort Drum ERCIP Well Field Expansion Project

Nick DeCristofaro & Vanja Dezelic

Fort Drum Army Airbase, New York

24RG60

31.6 Feet

3.1 Feet Above the Ground Surface

ARCADIS U.S.

NOTES: Acoustic caliper data can only be acquired in the water-filled portion of the borehole. The caliper data plotted in the logs below are 3-arm caliper data in the air-filled portion of the borehole and acoustic caliper data in the water-filled portion of the borehole.

A4-OBS-13 - Borehole Geophysical Logs

Depth

(Feet)

Depth

(Feet)

ATV Amplitude

0° 0°180°90° 270°

ATV Travel Time

0° 0°180°90° 270°

OTV Image

0° 0°180°90° 270°

Caliper

3 6(Inches)

Heat Pulse Flow Meter Under Ambient Conditions

-2 2(gpm)

Fluid Temperature

8.6 9.8(Degrees C)

Fluid Conductivity

150 600(uS/cm) Negative = Flow Down Positive = Flow Up no ATV, fluid conductivity, fluid temperature, and HPFM data above the water

Bottom of Casing

Water Level flow into & down the borehole flow into & down the borehole possible minor flow into or out of the borehole based on the fluid cond data flow out of the borehole no flow detected below ~60.5 feet flow dow n the borehole at~1.2 gpm flow dow n the borehole at~1.8 gpm flow dow n the borehole at~1.8 no flow

TOP OF CASING:

LOGS PROCESSED BY:

PROJECT REP(S) ON-SITE:

DATE(S) LOGGED:

PROJECT:

LOCATION:

LOGGING GEOPHYSICIST(S): ORIENTATION REFERENCE:

WATER LEVEL DEPTH:

HRGS FILE:CLIENT:

HRGS

dba HR Geological Services in New York

A4-OBS-14 - BOREHOLE GEOPHYSICAL LOGS

Top of the 4-Inch Steel Casing

3.8 Inches (HQ-Cored)

Atkinson, NH (603.893.9944) Fords, NJ (732.661.0555) www.hager-richter.com

True North (Magnetic Declination = 12° West)

Robert Garfield, P.G. & Nick DeCristofaro

Josh Miller

December 17 & 18, 2024

Fort Drum ERCIP Well Field Expansion Project

Fort Drum Army Airbase, New York

Nick DeCristofaro & Vanja Dezelic

27.4 Feet

24RG60

2.0 Feet Above the Ground Surface

ARCADIS U.S.

A4-OBS-14 - Borehole Geophysical Logs

Depth

(Feet)

Depth

(Feet)

ATV Amplitude

0° 0°180°90° 270°

ATV Travel Time

0° 0°180°90° 270°

OTV Image

0° 0°180°90° 270°

Caliper

3 6(Inches)

Heat Pulse Flow Meter Under Ambient Conditions

-2 2(gpm)

Fluid Temperature

8.6 9.5(Degrees C)

Fluid Conductivity

210 300(uS/cm) Negative = Flow Down Positive = Flow Up

Bottom of Casing flow into & down the borehole flow out of the borehole flow out of the borehole no flow detected below ~60.5 feet no flow detected in the casing no flow detected flow dow n the borehole at~1 gpm flow dow n the borehole at0.38

TOP OF CASING:

LOGS PROCESSED BY:

PROJECT REP(S) ON-SITE:

DATE(S) LOGGED:

PROJECT:

LOCATION:

LOGGING GEOPHYSICIST(S): ORIENTATION REFERENCE:

WATER LEVEL DEPTH:

HRGS FILE:CLIENT:

HRGS

dba HR Geological Services in New York

WELL-3R - BOREHOLE GEOPHYSICAL LOGS

Top of the 4-Inch Steel Casing

3.8 Inches (HQ-Cored)

Atkinson, NH (603.893.9944) Fords, NJ (732.661.0555) www.hager-richter.com

True North (Magnetic Declination = 12° West)

Robert Garfield, P.G. & Nick DeCristofaro

Josh Miller

December 17 & 18, 2024

Fort Drum ERCIP Well Field Expansion Project

Fort Drum Army Airbase, New York

Nick DeCristofaro & Vanja Dezelic

17.4 Feet

24RG60

2.8 Feet Above the Ground Surface

ARCADIS U.S.

Well-3R - Borehole Geophysical Logs

Depth

(Feet)

Depth

(Feet)

ATV Amplitude

0° 0°180°90° 270°

ATV Travel Time

0° 0°180°90° 270°

OTV Image

0° 0°180°90° 270°

Caliper

3 6(Inches)

Comments

Fluid Temperature

8.6 9.5(Degrees C)

Fluid Conductivity

270 360(uS/cm)

An obstruction encountered in the borehole at the time of logging prevented acquisition of borehole geophysical data below 24.5 feet with all of the logging probes other than the fluid temp/fluid cond probe, which advanced to the reported total depth of ~53 feet.

Bottom of Casing possible flow into or out of the borehole based on the fluid temp & fluid cond data possible flow into or out of the borehole based on the fluid cond data possible flow into or out of the borehole based on the fluid temp data possible flow into or out of the borehole based on the fluid cond data

TOP OF CASING:

LOGS PROCESSED BY:

PROJECT REP(S) ON-SITE:

DATE(S) LOGGED:

PROJECT:

LOCATION:

LOGGING GEOPHYSICIST(S): ORIENTATION REFERENCE:

WATER LEVEL DEPTH:

HRGS FILE:CLIENT:

HRGS

dba HR Geological Services in New York

WELL-4R - BOREHOLE GEOPHYSICAL LOGS

Top of the 4-Inch Steel Casing

3.8 Inches (HQ-Cored)

Atkinson, NH (603.893.9944) Fords, NJ (732.661.0555) www.hager-richter.com

True North (Magnetic Declination = 12° West)

Robert Garfield, P.G. & Nick DeCristofaro

Josh Miller

December 17 & 18, 2024

Fort Drum ERCIP Well Field Expansion Project

Fort Drum Army Airbase, New York

Nick DeCristofaro & Vanja Dezelic

32.4 Feet

24RG60

2.2 Feet Above the Ground Surface

ARCADIS U.S.

NOTES: Acoustic caliper data can only be acquired in the water-filled portion of the borehole. The caliper data plotted in the logs below are 3-arm caliper data in the air-filled portion of the borehole and acoustic caliper data in the water-filled portion of the borehole.

Well-4R - Borehole Geophysical Logs

Depth

(Feet)

Depth

(Feet)

ATV Amplitude

0° 0°180°90° 270°

ATV Travel Time

0° 0°180°90° 270°

OTV Image

0° 0°180°90° 270°

Caliper

3 6(Inches)

Heat Pulse Flow Meter Under Ambient Conditions

-2 2(gpm)

Fluid Temperature

7.5 8.7(Degrees C)

Fluid Conductivity

250 550(uS/cm) Negative = Flow Down Positive = Flow Up no ATV, fluid conductivity, fluid temperature, and HPFM data above the water

Bottom of Casing

Water Level flow into & down the borehole possible minor flow into or out of the borehole based on the fluid cond data flow out of the borehole minor flow into & up the borehole flow into & down the borehole from near/above the water level no flow detected below ~65 feet flow dow n 0.24 gpm flow dow n the borehole at~1.5 gpm flow dow n the borehole at~1.5 gpm flow up the borehole at0.03

Fort Drum Army Airbase, New York File 24RG60 January 2025

SUMMARY OF BOREHOLE FLOW TABLES

CLIENT ARCADIS U.S.

PROJECT Fort Drum ERCIP Well Field Expansion Project LOCATION Fort Drum Army Airbase, New York

HRGS FILE 24RG60

DATE LOGGED December 17 & 19, 2024 LOG DATUM Top of the 4‐Inch Steel Casing

Depth (Feet)

0.0 Top of the 4‐Inch Steel Casing

3.0 Ground Surface

4.9 Water Level

4.9 ‐ 25.0 no flow detected in the casing

25.0 Bottom of the 4‐Inch Steel Casing

25.0 ‐ 29.1 no flow detected

29.1 ‐ 30.6 flow into & down the borehole

30.6 ‐ 46.6 flow down the borehole at ~1 gpm

46.6 ‐ 46.9 flow out of the borehole

46.9 ‐ 54.5 no flow detected

54.5 ‐ 55.8 possible flow into or out of the borehole based on the fluid cond data

55.8 ‐ 122.8 no flow detected

122.8 Bottom of the Borehole (based on the geophysical logging)

Comments

HRGS

dba HR Geological Services in New York

A4‐OBS‐01D ‐ Summary of Borehole Flow Under Ambient Conditions

A4‐OBS‐01D ‐ Summary of Borehole Flow Under Ambient Conditions

LOCATION Fort Drum Army Airbase, New York

HRGS FILE 24RG60

DATE LOGGED December 18 & 19, 2024 LOG DATUM Top of the 4‐Inch Steel Casing

Depth (Feet)

0.0 Top of the 4‐Inch Steel Casing

2.9 Ground Surface

12.6 Water Level

12.6 ‐ 31.5 no flow detected in the casing

31.5 Bottom of the 4‐Inch Steel Casing

31.5 ‐ 43.5 no flow detected

43.5 ‐ 43.9 flow into & down the borehole

43.9 ‐ 63.2 flow down the borehole at ~1 gpm

63.2 ‐ 64.4 flow out of the borehole

64.4 ‐ 72.4 no flow detected

72.4 Bottom of the Borehole (based on the geophysical logging)

Comments

HRGS

dba HR Geological Services in New York

A4‐OBS‐11 ‐ Summary of Borehole Flow Under Ambient Conditions

A4‐OBS‐11 ‐ Summary of Borehole Flow Under Ambient Conditions

LOCATION Fort Drum Army Airbase, New York

HRGS FILE 24RG60

DATE LOGGED December 18, 2024 LOG DATUM Top of the 4‐Inch Steel Casing

Depth (Feet)

0.0 Top of the 4‐Inch Steel Casing

2.9 Ground Surface

28.9 Bottom of the 4‐Inch Steel Casing

35.5 Water Level

35.5 ‐ 37.4 no flow detected

37.4 ‐ 37.5 minor flow into & down the borehole

37.5 ‐ 40.3 flow down the borehole at 0.03 gpm

40.3 ‐ 40.7 flow into & down the borehole

40.7 ‐ 47.0 flow down the borehole at ~1 gpm

47.0 ‐ 47.2 possible minor flow into or out of the borehole based on staining evident in the OTV image

47.2 ‐ 53.9 flow down the borehole at ~1 gpm

53.9 ‐ 56.1 flow out of the borehole

56.1 ‐ 57.6 flow down the borehole at 0.02 gpm

57.6 ‐ 57.8 minor flow out of the borehole

57.8 ‐ 64.5 no flow detected

64.5 ‐ 64.6 possible flow into or out of the borehole based on the fluid cond data

64.6 ‐ 68.1 no flow detected

68.1 Bottom of the Borehole (based on the geophysical logging)

Comments

HRGS

dba HR Geological Services in New York

A4‐OBS‐12 ‐ Summary of Borehole Flow Under Ambient Conditions

A4‐OBS‐12 ‐ Summary of Borehole Flow Under Ambient Conditions

LOCATION Fort Drum Army Airbase, New York

HRGS FILE 24RG60

DATE LOGGED December 17 & 18, 2024 LOG DATUM Top of the 4‐Inch Steel Casing

Depth (Feet)

0.0 Top of the 4‐Inch Steel Casing

3.1 Ground Surface

21.0 Bottom of the 4‐Inch Steel Casing

31.6 Water Level

31.6 ‐ 32.4 no flow detected

32.4 ‐ 33.1 flow into & down the borehole

33.1 ‐ 40.5 flow down the borehole at ~1.2 gpm

40.5 ‐ 40.7 flow into & down the borehole

40.7 ‐ 46.8 flow down the borehole at ~1.8 gpm

46.8 ‐ 47.0 possible minor flow into or out of the borehole based on the fluid cond data

47.0 ‐ 57.5 flow down the borehole at ~1.8 gpm

57.5 ‐ 60.5 flow out of the borehole

60.5 ‐ 62.6 no flow detected

62.6 Bottom of the Borehole (based on the geophysical logging)

Comments

HRGS

dba HR Geological Services in New York

A4‐OBS‐13 ‐ Summary of Borehole Flow Under Ambient Conditions

A4‐OBS‐13 ‐ Summary of Borehole Flow Under Ambient Conditions

LOCATION Fort Drum Army Airbase, New York

HRGS FILE 24RG60

DATE LOGGED December 17 & 18, 2024 LOG DATUM Top of the 4‐Inch Steel Casing

Depth (Feet)

0.0 Top of the 4‐Inch Steel Casing

2.0 Ground Surface

27.4 Water Level

27.4 ‐ 30.0 no flow detected in the casing

30.0 Bottom of the 4‐Inch Steel Casing

30.0 ‐ 34.1 no flow detected

34.1 ‐ 34.6 flow into & down the borehole

34.6 ‐ 45.3 flow down the borehole at ~1 gpm

45.3 ‐ 48.0 flow out of the borehole

48.0 ‐ 57.7 flow down the borehole at 0.38 gpm

57.7 ‐ 60.4 flow out of the borehole

60.4 ‐ 66.6 no flow detected

66.6 Bottom of the Borehole (based on the geophysical logging)

Comments

HRGS

dba HR Geological Services in New York

A4‐OBS‐14 ‐ Summary of Borehole Flow Under Ambient Conditions

A4‐OBS‐14 ‐ Summary of Borehole Flow Under Ambient Conditions

LOCATION Fort Drum Army Airbase, New York

HRGS FILE 24RG60

DATE LOGGED December 17 & 18, 2024 LOG DATUM Top of the 4‐Inch Steel Casing

0.0 Top of the 4‐Inch Steel Casing

2.8 Ground Surface

17.4 Water Level

21.9 Bottom of the 4‐Inch Steel Casing

23.0 ‐ 25.5 possible flow into or out of the borehole based on the fluid temp & fluid cond data

29.5 ‐ 33.0 possible flow into or out of the borehole based on the fluid cond data

39.5 ‐ 42.0 possible flow into or out of the borehole based on the fluid cond data

50.5 ‐ 52.5 possible flow into or out of the borehole based on the fluid cond data

52.7 Bottom of the Borehole (based on the geophysical logging)

Comments An obstruction encountered in the borehole at 24.5 feet prevented acquisition of HPFM data.

The flow interpretation is based on the fluid temp & fluid cond data.

Depth

(Feet)

HRGS

dba HR Geological Services in New York Well‐3R ‐ Summary of Borehole Flow

Well‐3R ‐ Summary of Borehole Flow

LOCATION Fort Drum Army Airbase, New York

HRGS FILE 24RG60

DATE LOGGED December 17 & 18, 2024 LOG DATUM Top of the 4‐Inch Steel Casing

Depth (Feet)

0.0 Top of the 4‐Inch Steel Casing

2.2 Ground Surface

25.9 Bottom of the 4‐Inch Steel Casing

27.2 ‐ 32.4 flow into & down the borehole from fractures near or above the water level

32.4 Water Level

32.4 ‐ 33.9 flow down the borehole at 0.24 gpm

33.9 ‐ 36.6 flow into & down the borehole

36.6 ‐ 42.3 flow down the borehole at ~1.5 gpm

42.3 ‐ 42.7 possible minor flow into or out of the borehole based on the fluid cond data

42.7 ‐ 48.4 flow down the borehole at ~1.5 gpm

48.4 ‐ 48.7 flow out of the borehole

48.7 ‐ 61.7 flow up the borehole at 0.03 gpm

61.7 ‐ 64.9 minor flow into & up the borehole

64.9 ‐ 66.6 no flow detected

66.6 Bottom of the Borehole (based on the geophysical logging)

Comments

HRGS

dba HR Geological Services in New York

Well‐4R ‐ Summary of Borehole Flow Under Ambient Conditions

Well‐4R ‐ Summary of Borehole Flow Under Ambient Conditions

Arcadis. Improving quality of life.

Arcadis U.S., Inc.

One Lincoln Center, 110 West Fayette Street, Suite 300

Syracuse

New York 13202

Phone: 315 446 9120

Fax: 315 449 0017 www.arcadis.com

Colby Company Engineer ing

GEOTECHNICAL REPORTS

GEOTECHNICAL ENGINEERING REPORT

ENERGY RESILIENCE AND CONSERVATION INVESTMENT PROGRAM (ERCIP)

WELL FIELD EXPANSION PROJECT

UNITED STATES ARMY GARRISON - FORT DRUM, NEW YORK

Prepared for:

Colby Co. Engineering 47A York Street Portland, Maine

Prepared by:

Ransom Consulting, LLC

Pease International Tradeport 112 Corporate Drive

Portsmouth, New Hampshire 603.436.1490

Project 181.05025.005 November 27, 2023

Brian R. Pettingill, P.G.

Vice President Jay P. Johonnett P.E.

Consulting Geotechnical Engineer

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EXECUTIVE SUMMARY

Ransom Consulting, LLC (Ransom) has prepared this Geotechnical Engineering Report for Colby Co.

Engineering (Colby) for the proposed Energy Resilience and Conservation Investment Program (ERCIP) Well Field Expansion Project at Fort Drum, New York (the Site). This geotechnical report has been prepared in general accordance with the Scope of Work for ERCIP Well Field Expansion Project prepared by the United States Army Corps of Engineers, New York District for Contract W912DS19D0012, dated April 2022, “Geotechnical Survey” section, as well as our executed Purchase Order (P.O.) agreement with Colby (P.O. 408.007,001-5), dated January 30, 2023. This geotechnical engineering evaluation was performed to obtain site-specific subsurface soil information in support of design and construction of the water main for the proposed wellfield expansion project.

The proposed wellfield expansion project (Site) is located along the northwest periphery of the Wheeler- Sack Army Airfield at Fort Drum, New York. We understand that the proposed well field expansion project includes design and installation of approximately 22,500 linear feet of 18-inch HDPE water supply piping and access roads to new well houses along the route. The well field is located in the area of the intersection of Pleasant Street and Elm Lane, northwest of the airfield. The proposed water main is planned to be installed underground following the route of Elm Lane southeast to the intersection of Main Tank Trail, continuing southwest along Main Tank Trail to the water treatment plant.

The test borings were advanced to depths of approximately 12 to 14 feet below grade. Subsurface explorations generally encountered surficial layers of topsoil, underlain by either fine sand or silt.

Generally, borings conducted in areas adjacent to the airfield encountered sand, and borings conducted in the area of the well field encountered silt.

Water-saturated soils, inferred to be representative of groundwater, were not encountered in the test borings conducted. Groundwater levels at the Site will fluctuate due to season, temperature, precipitation, nearby underground utilities, and construction activity. Therefore, water levels at other times may differ from the observations made during this evaluation.

The naturally occurring sand and silt soils will likely be suitable for reuse as backfill in the water main trench. The sand soils will also likely be suitable for use as pipe bedding material. Gravel will likely need to be imported for base course materials in areas where the trench is located below road and driveway pavements.

Refusal, the depth at which the drilling equipment was not able to penetrate the deeper geologic formations, was encountered at test borings B4, B5, and B7 at a depth of 12 feet below grade. The bedrock surface is irregular, and it may be encountered at shallower depths along the path of the proposed water main. Excavation of one to two feet of bedrock could likely be excavated using mechanical and/or hydraulic methods, such as a hoe ram, without the need for blasting. If bedrock/boulder removal requires blasting, the techniques, and methods in the latest edition of the New York State Department of Transportation Standard Specifications should be followed. Blasting should also be performed in accordance with all local blasting ordinances. We recommend conducting additional test probes to evaluate the depth to bedrock along the proposed route. The additional probes should be located at offsets on either side of borings B4, B5, and B7 to evaluate the depth to bedrock between locations of prior shallow refusals. In addition, we recommend probes at locations midway between borings B1 through B4. The probes should be conducted by advancing the drilling equipment to the refusal depth or 15 feet, whichever is shallower. Soil sampling is not needed.

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The soils encountered in the boring program are considered to be frost susceptible (frost group S2 and F4 in accordance with UFC 3-260-02 Pavement Design for Airfields). The anticipated frost penetration is six feet below paved areas in accordance with Figure 20-5 of UFC 3-260-02, based on a design freezing index of 1,500-degree Fahrenheit days for Fort Drum, New York. Utilities planned with burial depths shallower than six feet should be designed with additional methods of frost protection.

In the event that changes in the design or location of the water main are made, the conclusions and recommendations contained in this report should not be considered valid unless they have been reviewed and modified or verified in writing by Ransom.

TABLE OF CONTENTS

1.0 INTRODUCTION

2.0 SITE AND PROJECT DESCRIPTIONS

2.1 Proposed Development

3.0 SUBSURFACE INVESTIGATION

3.1 Subsurface Explorations

3.2 Laboratory Testing

4.0 SUBSURFACE CONDITIONS

4.1 Subsurface Soils

4.1.1 Topsoil

4.1.2 Sand

4.1.3 Silt

4.2 Drilling Refusal/Bedrock

4.3 Groundwater

5.0 ENGINEERING EVALUATIONS

6.0 DESIGN RECOMMENDATIONS

6.1 Bedrock

6.2 Groundwater

6.3 Frost and Freezing Protection

7.0 EARTHWORK AND CONSTRUCTION RECOMMENDATIONS

7.1 Temporary Excavations

7.2 Dewatering and Runoff Control

7.3 Bedrock Excavation

7.4 Excavation and Backfilling

7.5 Reuse of Site Soils

7.6 Construction Monitoring

8.0 ADDITIONAL EXPLORATIONS

9.0 CLOSING COMMENTS

FIGURES:

Figure 1: Site Location Map Figure 2: Subsurface Exploration Location Plan

APPENDICES:

Appendix A: Exploration Logs Appendix B: Laboratory Test Report

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1.0 INTRODUCTION

Ransom Consulting, LLC (Ransom) has prepared this Geotechnical Engineering Report for Colby Co.

Engineering (Colby) for the proposed Energy Resilience and Conservation Investment Program (ERCIP) Well Field Expansion Project water main at Fort Drum, New York (the Site). This geotechnical report has been prepared in general accordance with the Scope of Work for ERCIP Well Field Expansion Project prepared by the United States Army Corps of Engineers, New York District for Contract W912DS19D0012, dated April 2022, “Geotechnical Survey” section, as well as our executed Purchase Order (P.O.) agreement with Colby (P.O. 408.007,001-5), dated January 30, 2023. The general location of the Site can be seen on Figure 1.

This geotechnical engineering evaluation was performed to obtain site-specific subsurface soil information in support of design and construction of the proposed wellfield expansion project water main.

As completed, Ransom’s scope of services included the following items:

1. Subcontracting and coordinating with a drilling contractor. Driller responsibilities included contacting the Dig Safely utility clearance system as required by New York law.

2. Providing technical monitoring for the subsurface explorations, collecting soil samples, and preparing exploration logs.

3. Submitting selected soil samples for laboratory geotechnical soil testing.

4. Evaluating the field and laboratory data with respect to the proposed development and preparing this report of our findings, evaluations, and recommendations for the proposed design and construction.

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2.0 SITE AND PROJECT DESCRIPTIONS

The proposed wellfield expansion project (Site) is located along the northwest periphery of the Wheeler- Sack Army Airfield at Fort Drum, New York. Based on the Black River, New York United States Geological Survey (USGS) 7.5-minute Quadrangle, topography in the area of the Site generally slopes down gently away from the airfield to the north at an elevation of around 680 feet above Mean Sea Level (MSL) to 550 feet above MSL at the northern extent of the proposed wellfield expansion area. A Site Location Map and Subsurface Exploration Plan are provided as Figures 1 and 2, respectively.

2.1 Proposed Development

We understand that the proposed well field expansion project includes design and installation of approximately 22,500 linear feet of 18-inch HDPE water supply piping and access roads to new well houses along the route. The well field is located in the area of the intersection of Pleasant Street and Elm Lane, north of the airfield. The proposed water main is planned to be installed underground following the route of Elm Lane southeast to the intersection of Main Tank Trail, continuing southwest along Main Tank Trail to the water treatment plant. The approximate area of the proposed well field and water main route are depicted on Figure 2.

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3.0 SUBSURFACE INVESTIGATION

The geotechnical subsurface exploration program was conducted for the Site from September 5-7, 2023, and consisted of 10 test borings (designated B1 through B10), as shown on Figure 2. The explorations were not surveyed; their locations should be considered approximate.

3.1 Subsurface Explorations

The test borings were performed by Atlantic Testing Laboratories of Watertown, New York, with a track-mounted drill rig using a combination of hollow-stem auger and washed rotary drilling techniques. Split barrel sampling with standard penetration testing was conducted using an automatic drive hammer.

A Ransom representative monitored subsurface exploration activities, prepared field boring logs, and measured the depths to groundwater saturated soils when encountered. Soil samples were placed in sealed containers and returned to Ransom’s office for further evaluation and laboratory testing. Soil samples were visually classified using modified Burmister Soil Classification System descriptors.

Exploration logs are included in Appendix A.

3.2 Laboratory Testing

The geotechnical soil index testing was performed on select samples by Civil Connection of Canterbury, New Hampshire. The samples were submitted for one or more of the following geotechnical laboratory tests performed in general accordance with the applicable ASTM procedures:

1. Grain size by ASTM D6913; and

2. Hydrometer analysis by ASTM D7928.

The results of the laboratory analytical tests are presented in the laboratory report included in Appendix B.

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4.0 SUBSURFACE CONDITIONS

Subsurface conditions at the Site were characterized by advancing test borings into the unconsolidated overburden soil formations at accessible locations at the Site. Figure 2 illustrates the proposed Site features and approximate test boring locations.

4.1 Subsurface Soils

The test borings were advanced to depths of approximately 12 to 14 feet below grade. Subsurface explorations generally encountered surficial layers of topsoil, underlain by either fine sand or silt.

Generally, borings conducted in areas adjacent to the airfield encountered sand, and borings conducted in the area of the well field encountered silt. The general characteristics of the subsurface layers are described below.

4.1.1 Topsoil

A thin layer of topsoil was encountered at the ground surface at each boring location. The topsoil generally consisted of dark brown silty sand with organics. The topsoil ranged in thickness from approximately one to four inches.

4.1.2 Sand

A fine to medium-grained sand deposit was encountered beneath the topsoil in borings B1 through B5 of the soil borings. This unit generally consisted of light brown fine to medium sand with varying amounts of silt. The sand was generally observed to be in a loose to very dense condition, with density generally increasing with depth. Visual classification and laboratory grain-size distribution tests indicate that this soil is classified as silty sand (SM) in general accordance with the United Soil Classification System (USCS).

4.1.3 Silt

A silt deposit was encountered beneath the topsoil in borings B6 through B10 and also in boring B4 beneath the sand unit. The silt unit generally consisted of light brown silt with some clay.

The silt was observed to be in a stiff to hard condition at borings B6 through B8. The silt at borings B9 and B10 was generally observed to be in a soft to medium stiff condition. A layer of sand and gravel was observed beneath the silt at boring B10. Visual classification and laboratory grain-size distribution tests indicate that this soil is classified as silt (ML) in general accordance with the USCS.

4.2 Drilling Refusal/Bedrock

Refusal, the depth at which the drilling equipment was not able to penetrate the deeper geologic formations, was encountered at test borings B4, B5, and B7 at a depth of 12 feet below grade.

4.3 Groundwater

Water-saturated soils, inferred to be representative of groundwater, were not encountered in the test borings conducted. Groundwater levels at the Site will fluctuate due to season, temperature, precipitation, Project 181.05025.005 Page 5 \\portsmth-fp01\Projects\2018\181.05025\005 - Well Field Expansion\Report\Text.docx November 27, 2023 nearby underground utilities, and construction activity. Therefore, water levels at other times may differ from the observations made during this evaluation.

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5.0 ENGINEERING EVALUATIONS

The subsurface explorations generally encountered surficial layers of topsoil overlying sand and/or silt.

The controlling geotechnical features for the construction of the proposed well field expansion water main are:

1. Reuse of Site Soils. The naturally occurring sand and silt soils will likely be suitable for reuse as backfill in the water main trench. The sand soils will also likely be suitable for use as pipe bedding material. Gravel will likely need to be imported for base course materials in areas where the trench is located below road and driveway pavements.

2. Bedrock. Drilling refusal was encountered in borings B4, B5, and B7 at a depth of 12 feet below grade which we infer to be the competent bedrock surface. The bedrock surface is irregular, and it may be encountered at shallower depths along the path of the proposed water main.

Geotechnical engineering evaluations for this project are based on the subsurface conditions interpreted from widely spaced subsurface explorations along the water main path, laboratory testing, and the project design information currently available. Should differing information become known prior to or during construction, the following evaluations and recommendations should be reviewed by Ransom and modifications to these evaluations may be necessary.

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6.0 DESIGN RECOMMENDATIONS

Based on the subsurface explorations and our geotechnical evaluations, Ransom presents the following recommendations for the proposed well field expansion water main at Fort Drum, New York.

6.1 Bedrock

Drilling refusal was encountered in borings B4, B5, and B7 at a depth of 12 feet below grade which we infer to be the competent bedrock surface. The bedrock surface is irregular and bedrock and/or large boulders could be encountered at shallower depths along the path of the proposed water main. Additional test probes could be conducted to evaluate the depth to bedrock along the proposed route. The depth to bedrock should be considered when designing the water main to minimize the amount of bedrock removal that could be required where possible.

Where bedrock is encountered above design pipe elevations, undercutting of the bedrock should be performed in accordance with the pipe manufacturer’s recommendations and a minimum of 6 inches below the proposed pipe invert.

Excavation of one to two feet of bedrock could likely be accomplished using mechanical and/or hydraulic methods, such as hoe rams, without the need for blasting. Removal of greater bedrock thicknesses could require blasting.

6.2 Groundwater

Groundwater, believed to be representative of the stabilized groundwater table, was not observed during subsurface explorations advanced to a maximum depth of 14 feet below ground surface. We understand that several stream crossings will be required. The elevations of existing culverts or bridge structures should be considered when designing the water main.

6.3 Frost and Freezing Protection

The soils encountered in the boring program are considered to be frost susceptible (frost group S2 and F4 in accordance with UFC 3-260-02 Pavement Design for Airfields). The anticipated frost penetration is six feet below paved areas in accordance with Figure 20-5 of UFC 3-260-02, based on a design freezing index of 1,500-degree Fahrenheit days for Fort Drum, New York. Utilities planned with burial depths shallower than six feet should be designed with additional methods of frost protection.

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7.0 EARTHWORK AND CONSTRUCTION RECOMMENDATIONS

Based on the subsurface explorations and our geotechnical evaluations, Ransom presents the following recommendations for the construction of the proposed well field expansion water main at Fort Drum, New York.

7.1 Temporary Excavations

We have assumed that the utility excavations will be through cut-and-cover methods using trench boxes to provide temporary support to the deepest stretches of open trenches. It has been our experience that the ground surface around trench boxes could settle, leading to subsidence of adjacent roadways, sidewalks, and the ground without adequate engineering design. Lateral excavation support should be designed by a New York licensed Professional Engineer. The design should be submitted to Ransom as a shop drawing for review.

All temporary excavations should be performed according to Occupational Safety and Health Administration (OSHA) Standards (29 CFR 1926 Subpart P). The contractor’s competent person will be responsible for monitoring the height, slope, and depths of the excavations in accordance with these regulations.

7.2 Dewatering and Runoff Control

Groundwater, believed to be representative of the stabilized groundwater table, was not observed during subsurface explorations advanced to a maximum depth of 14 feet below ground surface. Groundwater levels at the Site will fluctuate due to seasonal effects, temperature, precipitation, nearby underground utilities, and construction activity. Therefore, water levels at other times may differ from the observations and measurements made during drilling. Construction dewatering should be provided where water is encountered so as to allow construction to be accomplished “in the dry.”

It is our opinion that groundwater from these types of soils and anticipated excavation depths could potentially be controlled through pumping from open sumps. Should free-draining soils be encountered, pumping from sumps might not provide sufficient groundwater control.

Surface water runoff should be directed away from excavations to reduce dewatering efforts and to protect subgrades from becoming soft and unstable. The contractor should anticipate the need for controlling runoff during wet periods.

The contractor should be aware that the presence of groundwater can destabilize trench walls. This potential should be taken into account in determinations of the stability of the trenches, as well as the trench heights and lateral support methods.

7.3 Bedrock Excavation

Excavation of one to two feet of bedrock could likely be excavated using mechanical and/or hydraulic methods, such as a hoe ram, without the need for blasting. If bedrock/boulder removal requires blasting, the techniques, and methods in the latest edition of the New York State Department of Transportation Standard Specifications should be followed. Blasting should also be performed in accordance with all local blasting ordinances.

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7.4 Excavation and Backfilling

Excavation within fine grained soils (naturally occurring silt soils) should be accomplished using a smooth-edged bucket to minimize disturbance to the underlying subgrade soils; disturbance from toothed buckets could increase settlement of the backfilled soils after construction. Disturbed soils should be removed or compacted prior to placing pipe bedding materials. Boulders and loose bedrock should be removed prior to placing pipe bedding.

The soils that will be excavated from the utility trench could require control of the moisture content before being approved for use as backfill. Where subgrades become saturated, unstable, and/or difficult to compact, crushed stone should be placed and compacted in lieu of structural fill. Crushed stone, when used, should be wrapped in a geotextile filter fabric, such as Mirafi 140N or equal.

All backfill soils should be placed in 12-inch maximum loose lifts and should be compacted to a minimum of 95 percent of the material’s maximum dry density, as determined by ASTM D1557 (modified Proctor test) and verified with field density testing (ASTM D6938 or equivalent method). Lift thickness should be a maximum of 6-inch loose lifts when compacted with hand-guided equipment.

Compaction to less than 95 percent could result in settlement of the backfills within the trench, which could damage the overlying pavement.

Bedding placed below utilities should be in accordance with the utility and manufacturer requirements. In general, utilities may be supported directly on a minimum 6-inch-thick layer of compacted fill, crushed stone, or other suitable pipe bedding materials.

7.5 Reuse of Site Soils

Excavations will encounter sand, silt, and potentially bedrock in areas. These materials should generally be suitable for backfills within the trenches. The sand soils will also likely be suitable for use as pipe bedding material. If crushed stone is used for backfilling, a geotextile separator fabric (Mirafi 140N, for example) should be placed between the crushed stone and the in-place soils. Gravel will likely need to be imported for aggregate base and subbase course materials in paved roadway areas.

Representative samples of all proposed fills should be submitted for testing during construction to compare their gradation characteristics to the requirements of the project specifications, and to establish their optimum water contents and maximum dry densities (modified Proctor testing, ASTM D1557). The geotechnical engineer must approve use and reuse of on-site or borrow soils for fill materials. Use of fills assumes that the moisture content of the material will be strictly controlled in order to allow for proper placement and compaction.

7.6 Construction Monitoring

Ransom should be provided the opportunity to review the final design and specifications to ensure our recommendations presented herein have been properly interpreted and applied. Ransom recommends that all fill, backfill, and compaction be inspected and tested by a qualified firm to make sure the proper materials are placed and adequately compacted. Ransom should review all soil inspection and testing reports. Ransom should be retained to provide construction observation and documentation for the following aspects of site development:

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1. Observe soil subgrade conditions as they are exposed and confirm that the exposed conditions are consistent with those in this report;

2. Document the preparation of foundation bearing surfaces and other subgrades;

3. Determine the need for additional cut, backfill, or stabilization of subgrades; and

4. Confirm that the soils used as fills and backfills conform to the project specifications.

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8.0 ADDITIONAL EXPLORATIONS

Drilling refusal was encountered in borings B4, B5, and B7 at a depth of 12 feet below grade which we infer to be the competent bedrock surface. The bedrock surface is irregular and bedrock and/or large boulders could be encountered at shallower depths along the path of the proposed water main. We recommend conducting additional test probes to evaluate the depth to bedrock along the proposed route.

The additional probes should be located at offsets on either side of borings B4, B5, and B7 to evaluate the depth to bedrock between locations of prior shallow refusals. In addition, we recommend probes at locations midway between borings B1 through B4.