GLAC307440_Final_CD_ProjectManual_Division_2-43.pdf

National Park Service (NPS) Replace Headquarters Wastewater System & Backup Power System for Main Building

GLAC 307440

Construction Documents Project Manual Division 2 - 43

APRIL 2023

HDR Project No. HQ10355285

GLAC - 307440

SEALS AND SIGNATURES

Owner Name: National Park Service

Facility or Site Name: Glacier National Park

Project Name: Headquarters Wastewater System and Backup Power System

Project or Contract Designation: GLAC 307440

Engineers: HDR & DJ&A

Rickey Schultz, PE

License No. 18171

The seal and signature to the left applies to the following Specifications divisions and sections of this project manual:

• 02 06 13 and 02 41 00

Jarrett Moran, PE

License No. 75162

• 05 50 00, 07 90 00, 08 31 00, 09 96

00, 10 14 00, 33 75 00, 40 05 00, 40 05 07, 40 05 19, 40 05 31, 40 05

51, 40 05 52, 40 05 61, 40 05 62, 40 05 66, 40 71 00, 40 72 00, 40 73

00, 43 21 00, and 43 25 13

GLAC - 307440

Terrance Stulc, PE

License No. 63196

The seal and signature to the left applies to

• 26 05 00, 26 05 19, 26 05 26, 26 05

33, 26 05 43, 26 08 13, 26 09 16, 26 22 13, 26 24 16, 26 24 19, 26 27

26, 26 28 00, 26 28 16, 26 28 17, 26 29 23, 26 32 15, 26 36 00, 26 43

13, 40 63 43, 40 66 05, 40 66 40, 40 67 00, 40 67 63, 40 68 13, and

40 68 63

Michael Whelehon, PE

License No. 16888

The seal and signature to the left applies to

• 02 21 13, 31 10 00, 31 23 00, 31 23

33, 32 01 01, 32 11 23, 32 12 16, 32 13 13, 32 91 13, 32 92 19.23, 33

05 16, and 33 31 11

Christopher Yarn, PE

License No. 72708

• 03 00 05 and 03 35 00

Engineer’s seal and signature does not apply to the documents that comprise Division 00, Bidding and Contracting Requirements.

It is a violation of applicable laws and regulations governing professional licensing and registration for any person, unless acting under the direction of the licensed and registered design professional(s) indicated above, to alter in any way the Specifications in this project manual.

HDR Project No. HQ10355285 National Park Service - Headquarters Construction Documents April 2023

Table of Contents

00 01 10 - 1

TABLE OF CONTENTS

DIVISION 02 — EXISTING CONDITIONS

02 06 13 - GEOTECHNICAL BASELINE REPORT

02 41 00 - DEMOLITION

DIVISION 03 — CONCRETE

03 00 05 - CONCRETE

03 15 19 - ANCHORAGE TO CONCRETE

03 35 00 - CONCRETE FINISHING AND REPAIR OF SURFACE DEFECTS

03 41 33 - PRECAST AND PRESTRESSED CONCRETE

DIVISION 05 — METALS

05 50 00 - METAL FABRICATIONS

DIVISION 07 — THERMAL AND MOISTURE PROTECTION

07 92 00 - JOINT SEALANTS

DIVISION 08 — OPENINGS

08 31 00 - ACCESS DOORS

DIVISION 09 — FINISHES

09 96 00 - HIGH PERFORMANCE INDUSTRIAL COATINGS

DIVISION 10 — SPECIALTIES

10 14 00 - IDENTIFICATION DEVICES

DIVISION 26 — ELECTRICAL

26 05 00 - ELECTRICAL - BASIC REQUIREMENTS

26 05 09 - MOTORS

26 05 19 - WIRE AND CABLE - 600 VOLT AND BELOW

26 05 26 - GROUNDING AND BONDING

26 05 33 - RACEWAYS AND BOXES

26 05 43 - ELECTRICAL - EXTERIOR UNDERGROUND

26 08 13 - ACCEPTANCE TESTING

26 09 13 - ELECTRICAL METERING DEVICES

26 09 16 - CONTROL EQUIPMENT ACCESSORIES

26 22 13 - DRY-TYPE TRANSFORMERS

26 24 16 - PANELBOARDS

26 24 19 - MOTOR CONTROL EQUIPMENT

26 27 26 - WIRING DEVICES

26 28 00 - OVERCURRENT AND SHORT CIRCUIT PROTECTIVE DEVICES

26 28 16 - SAFETY SWITCHES

26 28 17 - SEPARATELY MOUNTED CIRCUIT BREAKERS

26 29 23 - VARIABLE FREQUENCY DRIVES - LOW VOLTAGE

26 32 15 - ENGINE GENERATOR - NATURAL GAS

26 36 00 - TRANSFER SWITCHES

26 43 13 - SURGE PROTECTION DEVICES FOR LOW-VOLTAGE ELECTRICAL POWER

CIRCUITS

DIVISION 31 — EARTHWORK

31 10 00 - SITE CLEARING

31 23 00 - EARTHWORK

31 23 33 - TRENCHING, BACKFILLING, AND COMPACTING FOR UTILITIES

DIVISION 32 — EXTERIOR IMPROVEMENTS

32 11 23 - AGGREGATE BASE COURSE

32 12 16 - ASPHALTIC CONCRETE VEHICULAR PAVING

32 91 13 - TOPSOILING AND FINISHED GRADING

Table of Contents

00 01 10 - 2

DIVISION 33 — UTILITIES

33 05 16 - PRECAST CONCRETE STRUCTURES

33 31 11 - GRAVITY SEWER PIPELINE AND MANHOLE CONSTRUCTION

33 75 00 - TEMPORARY WASTEWATER BYPASS PUMPING SYSTEMS

DIVISION 40 — PROCESS INTERCONNECTIONS

40 05 00 - PIPE AND PIPE FITTINGS - BASIC REQUIREMENTS

40 05 07 - PIPE SUPPORT SYSTEMS

40 05 19 - PIPE - DUCTILE IRON

40 05 31 - PIPE - PLASTIC

40 05 51 - VALVES - BASIC REQUIREMENTS

40 05 52 - MISCELLANEOUS VALVES

40 05 61 - GATE VALVES

40 05 62 - PLUG VALVES

40 05 66 - CHECK VALVES

40 63 43 - PROGRAMMABLE LOGIC CONTROLLERS

40 67 00 - CONTROL SYSTEM EQUIPMENT PANELS AND RACKS REV

40 67 63 - UNINTERRUPTIBLE POWER SUPPLY

40 68 63 - CONFIGURATION OF HMI SOFTWARE AND REPORTS

40 71 00 - FLOW INSTRUMENTATION

40 72 00 - LEVEL INSTRUMENTATION

40 73 00 - PRESSURE INSTRUMENTATION

DIVISION 43 — PROCESS GAS AND LIQUID HANDLING, PURIFICATION AND STORAGE

EQUIPMENT

43 21 00 - PUMPING EQUIPMENT - BASIC REQUIREMENTS

43 25 13 - PUMPING EQUIPMENT - SUBMERSIBLE END-SUCTION SEWAGE PUMPS

D I V I S I O N 0 2

EXISTING CONDITIONS

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GEOTECHNICAL BASELINE REPORT

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SECTION 02 06 13

GEOTECHNICAL BASELINE REPORT

PART 1 - GENERAL

1.1 SUMMARY

A. Section Includes:

1. The Project’s Geotechnical Baseline Report (GBR), which is attached to this Specifications section.

2. Contractual requirements associated with the GBR and related documents and information.

B. Provisions of the Geotechnical Baseline Report apply to all contractors engaged by Contracting

Officer under the Project.

1.2 REFERENCES

A. Definitions: The following terms are defined for use in this Specifications section and are indicated herein using initial capital letters. The terms have the associated meaning regardless of whether indicated in singular or plural:

1. Baseline Conditions: Has the meaning indicated in Paragraph 1.3.E of this Specifications

Section.

2. Geotechnical Baseline Report (GBR): The interpretive report prepared by or for

Contracting Officer regarding subsurface conditions at the Site, and containing specific baseline geotechnical conditions that may be anticipated or relied upon for bidding and contract administration purposes, subject to the controlling provisions of the Contract

Documents, including the GBR’s own terms. The GBR is a Contract Document.

3. Geotechnical Data Report (GDR): The factual report that collects and presents data regarding actual subsurface conditions at or adjacent to the Site, including Technical Data and other geotechnical data, prepared by or for Contracting Officer in support of the

Geotechnical Baseline Report. The GDR’s content may include logs of borings, trenches, and other site investigations, recorded measurements of subsurface water levels, the results of field and laboratory testing, and descriptions of the investigative and testing programs.

The GDR does not include an interpretation of the data. If opinions, or interpretive or speculative non-factual comments or statements appear in a document that is labeled a

GDR, such opinions, comments, or statements are not operative parts of the GDR and do not have contractual standing. Subject to that exception, the GDR is a Contract Document.

4. Technical Data: For this Specifications section, the term “Technical Data” has the same meaning as set forth in the General Conditions, as may be modified by the Supplementary

Conditions.

1.3 SUBSURFACE AND PHYSICAL CONDITIONS

A. Reports and Drawings: This article hereby identifies:

1. Those reports of explorations and tests of subsurface conditions at or adjacent to the Site

(other than any Geotechnical Data Report or Geotechnical Baseline Report) that contain

Technical Data. Such reports are as follows:

a. Report Title: Preliminary Geotechnical Report, Glacier National Park Headquarters and Swiftcurrent Utility Improvements.

1) Date of Report: December 2022.

2) Technical Data in report upon which Contractor may rely: Preliminary geotechnical engineering recommendations.

2. Those Drawings of existing physical conditions at or adjacent to the Site, including those drawings depicting existing surface or subsurface structures at or adjacent to the Site (except

Underground Facilities), that contain Technical Data.

GEOTECHNICAL BASELINE REPORT

02 06 13 - 2

B. Underground Facilities: Underground Facilities are shown or indicated on the Drawings, pursuant to the General Conditions, and not in the drawings referred to in Paragraph 1.3.A.2 of this Specifications section. Information and data regarding the presence or location of

Underground Facilities are not intended to be categorized, identified, or defined as Technical

Data.

C. Reliance by Contractor on Technical Data Authorized:

1. Contractor may rely upon the accuracy of the Technical Data expressly identified in

Paragraph 1.3.A of this Specifications section with respect to such reports and drawings, but such reports and drawings are not Contract Documents.

D. Limitations of Other Data and Documents: Except for such reliance on Technical Data, Contractor may not rely upon or make any claim against Contracting Officer or Contracting officer Representative, or any of their officers, directors, members, partners, employees, agents, consultants, or subcontractors, with respect to:

1. the completeness of such reports and drawings for Contractor’s purposes, including, but not limited to, any aspects of the means, methods, techniques, sequences, and procedures of construction to be employed by Contractor, and safety precautions and programs incident thereto; or.

2. other data, interpretations, opinions, and information contained in such reports or shown or indicated in such drawings; or.

3. the contents of other Site-related documents made available to Contractor, such as record drawings from other projects at or adjacent to the Site, or Contracting Officer’s archival documents concerning the Site; or.

4. any Contractor interpretation of or conclusion drawn from any Technical Data or any such other data, interpretations, opinions, or information.

E. Geotechnical Baseline Report:

1. This Contract includes a Geotechnical Baseline Report (“GBR”), identified as follows:

Preliminary Geotechnical Report, Glacier National Park Headquarters and Swiftcurrent

Utility Improvements.

2. GBR and GDR are incorporated as Contract Documents as attachments to this

Specifications section. Use the GBR and GDR in conjunction with other Contract

Documents, including the Drawings and Specifications. If there is a conflict between the terms of GBR and GDR, the GBR’s terms prevail.

3. GBR describes certain, select subsurface conditions that are anticipated to be encountered by Contractor during construction in specified locations (referred to in this Specifications section as “Baseline Conditions”). These may include ground, geological, groundwater, and other subsurface geotechnical conditions, and baselines of anticipated Underground

Facilities or subsurface structures.

4. Baseline Conditions will be used to assist in administration of the Contract’s differing site conditions clause at locations where subsurface conditions have been baselined. If a condition is baselined in the GBR, then only the pertinent Baseline Conditions will be used to determine whether there is a differing site condition; and no other indication of that condition in the Contract Documents or Technical Data, or of a condition that describes, quantifies, or measures a similar characteristic of the subsurface, will be used for the differing site condition determination.

5. Baseline Conditions will not be used to make differing site conditions determinations at locations that have not been baselined in the GBR, or at any location with respect to subsurface conditions that Baseline Conditions do not address. If Underground Facilities or

Hazardous Environmental Conditions are expressly addressed in Baseline Conditions, then comparison to such Baseline Conditions will be the primary means of determining (a) whether an Underground Facility was shown or indicated with reasonable accuracy, as provided in the General Conditions, or (b) whether a Hazardous Environmental Condition was shown or indicated in the Contract Documents as indicated in the General Conditions.

GEOTECHNICAL BASELINE REPORT

02 06 13 - 3

As indicated in Article1.4 of this Specification section, GDR will be the primary resource for differing site conditions determinations in cases in which the GBR is inapplicable.

6. Descriptions of subsurface conditions in the GBR are based on geotechnical investigations, laboratory tests, interpretation, interpolation, extrapolation, and analyses. Neither

Contracting Officer, Contracting Officer Representative, nor any geotechnical or other consultant or subcontractor warrants or guarantees that actual subsurface conditions will be as described in the GBR, nor is the GBR intended to warrant or guarantee the use of specific means, methods, procedures, techniques, or sequences of construction.

7. Behavior of the ground during construction depends substantially upon Contractor’s selected means, methods, techniques, sequences, and procedures of construction. If ground behavior conditions are baselined in GBR, they are based on stated assumptions regarding construction means, methods, procedures, techniques, and sequences of construction.

8. GBR will not reduce or relieve Contractor of Contractor’s responsibility for planning, selection, and implementation of safety precautions and programs incident to Contractor’s means, methods, techniques, sequences, and procedures of construction, or to the Work.

1.4 DIFFERING SUBSURFACE AND PHYSICAL CONDITIONS

A. Notice: If Contractor believes that any subsurface condition that is uncovered or revealed at the

Site:

1. differs materially from conditions shown or indicated in GBR; or.

2. differs materially from conditions shown or indicated in GDR, to the extent GBR is inapplicable; or.

3. differs materially from conditions shown or indicated in the Contract Documents other than the GBR or GDR, to the extent the GBR and GDR are inapplicable; or.

4. to the extent the GBR and GDR are inapplicable, is of such a nature as to establish that any

Technical Data on which Contractor is entitled to rely as provided in Paragraph 1.3.A of this

Specification section is materially inaccurate; or.

5. to the extent the GBR and GDR are inapplicable, is of such a nature as to require a change in the Drawings or Specifications; or.

6. to the extent the GBR and GDR are inapplicable, is of an unusual nature, and differs materially from conditions ordinarily encountered and generally recognized as inherent in work of the character provided for in the Contract Documents; or.

7. Contractor encounters human remains, recognizes the existence of burial markers, archaeological sites, historical sites, artifacts of potential archaeological or historical interest, or wetlands not shown or indicated in the Contract Documents, Contractor shall immediately cease operations that may disturb such area(s) and secure the adjacent Work;

and Contracting Officer shall promptly take any action necessary to obtain governmental authorization required to resume the operations (Contractor shall continue to suspend such operations until otherwise instructed by Contracting Officer but shall continue with all other operations that do not affect those remains or features);

8. then Contractor shall, promptly after becoming aware thereof and before further disturbing the subsurface conditions or performing any Work in connection therewith notify

Contracting Officer and Contracting Officer Representative in writing about such condition.

Contractor shall not further disturb such condition or perform any Work in connection therewith (except with respect to an emergency) until receipt of a written statement permitting Contractor to do so.

B. Contracting Officer Representative’s Review:

1. After receipt of written notice as required by Paragraph 1.4.A of this Specifications Section, Contracting Officer Representative will promptly:

a. review the subsurface or physical condition in question;

b. determine the necessity of Contracting Officer’s obtaining additional exploration or tests with respect to the condition;

c. conclude whether the condition falls within any one or more of the differing site condition categories in Paragraph 1.4.A of this Specifications section;

d. obtain any pertinent cost or schedule information from Contractor;

GEOTECHNICAL BASELINE REPORT

02 06 13 - 4

e. prepare recommendations to Contracting Officer regarding the Contractor’s resumption or continuation of Work in connection with the subsurface or physical condition in question and the need for any change in the Drawings or Specifications; and

f. advise Contracting Officer in writing of Contracting Officer Representative’s findings, conclusions, and recommendations.

C. Contracting Officer’s Statement to Contractor Regarding Site Condition: After receipt of

Contracting Officer Representative’s written findings, conclusions, and recommendations, Contracting Officer shall issue a written statement to Contractor (with a copy to Contracting

Officer Representative) regarding the subsurface or physical condition in question, addressing the resumption or continuation of Work in connection with such condition, indicating whether any change in the Drawings or Specifications will be made, and adopting or rejecting

Contracting Officer Representative’s written findings, conclusions, and recommendations, in whole or in part.

D. Early Resumption of Work: If at, any time, Contracting Officer Representative determines that

Work in connection with the subsurface or physical condition in question may resume prior to completion of Contracting Officer Representative’s review or Contracting Officer’s issuance of its statement to Contractor, because the condition in question has been adequately documented, and evaluated on a preliminary basis, then Contracting Officer Representative may, at

Contracting Officer Representatives’ discretion, instruct Contractor to resume such Work.

E. Possible Price and Times Adjustments:

1. Contractor shall be entitled to an equitable adjustment in Contract Price, Contract Times, or both to the extent that the existence of a differing subsurface or physical condition, or any related delay, disruption, or interference, causes an increase or decrease in Contractor’s cost of, or time required for, performance of the Work; subject, however, to the following:

a. such condition must fall within any one or more of the categories described in

Paragraph 1.4.A of this Specifications Section;

b. with respect to Work that is paid for on a unit price basis, any adjustment in Contract

Price will be subject to the provisions of the General Conditions; and.

c. Contractor’s entitlement to an adjustment of the Contract Times is subject to the provisions of the General Conditions.

2. Contractor shall not be entitled to any adjustment in either the Contract Price or Contract

Times with respect to a subsurface or physical condition if:

a. Contractor knew of the existence of such condition at the time Contractor made a commitment to Contracting Officer with respect to Contract Price and Contract Times by the submission of a Bid or becoming bound under a negotiated contract, or otherwise; or.

b. the existence of such condition reasonably could have been discovered or revealed as a result of any examination, investigation, exploration, test, or study of the Site and contiguous areas expressly required by the Bidding Requirements or Contract

Documents to be conducted by or for Contractor prior to Contractor’s making such commitment; or.

c. Contractor failed to give the written notice as required by Paragraph 1.4.A of this

Specifications section.

3. If Contracting Officer and Contractor agree regarding Contractor’s entitlement to and the amount or extent of any adjustment in the Contract Price, Contract Times, or both, then any such adjustment shall be set forth in a Change Order.

4. Contractor may submit a Change Proposal regarding its entitlement to or the amount or extent of any adjustment in the Contract Price, Contract Times, or both, not later than 30 days after Contracting Officer’s issuance of the Contracting Officer’s written statement to

Contractor regarding the subsurface or physical condition in question.

F. Underground Facilities; Hazardous Environmental Conditions: the General Conditions governs rights and responsibilities regarding the presence or location of Underground Facilities. The

General Conditions governs rights and responsibilities regarding Hazardous Environmental

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Conditions. The provisions of Articles 1.3 and 1.4 of this Specifications section are not applicable to the presence or location of Underground Facilities, or to Hazardous Environmental

Conditions.

PART 2 - PRODUCTS - (NOT USED)

PART 3 - EXECUTION

3.1 ATTACHMENTS

A. The documents listed below, and attached following this Specification section’s “End of

Section” designation, are part of this Specifications section.

1. Geotechnical Baseline Report, titled, Preliminary Geotechnical Report, Glacier National

Park Headquarters and Swiftcurrent Utility Improvements.

END OF SECTION

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SUBMITTED TO:

HDR Engineering, Inc.

700 SW Higgins Ave., Suite 200 Missoula, MT 59803

BY:

Shannon & Wilson 1321 Bannock Street, Ste 200 Denver, CO 80204

(303) 825-3800 www.shannonwilson.com

PRELIMINARY GEOTECHNICAL REPORT

NPS Glacier National Park Headquarters and Swiftcurrent Utility Improvements

FLATHEAD & GLACIER COUNITES, MONTANA

December 2022

Shannon & Wilson No: 107857-001

Headquarters and Swiftcurrent

Preliminary Geotechnical Report

107857-001 December 2022 ii

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CONTENTS

1 Introduction

2 Site Description

2.1 Headquarters Site

2.2 Swiftcurrent Site

3 Project Description

3.1 GLAC 307440 Replace Headquarters Wastewater & Backup Power Systems

3.2 GLAC 307606 Swiftcurrent Water Distribution System Improvements

4 Field Explorations and Laboratory Testing

5 Geologic Setting and Subsurface Conditions

5.1 Regional Geology

5.1.1 Headquarters Site

5.1.2 Swiftcurrent Site

5.2 Subsurface Conditions

5.2.1 Headquarters Site

5.2.2 Swiftcurrent Site

5.3 Groundwater

5.4 Subsurface Variation

6 Geologic Hazard Evaluation

6.1 Seismic Hazards

6.2 Corrosive Soil and Bedrock

7 Preliminary Geotechnical Engineering Recommendations

7.1 Seismic Design Considerations

7.2 Below Grade Water Tank

7.2.1 Foundations

7.2.2 Lateral Earth Pressures

7.2.3 Lateral Resistance

7.2.4 Drainage

7.3 Pipelines and Manholes

7.3.1 Loads on Pipes

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7.3.2 Thrust Restraint

7.3.3 Manhole Foundations

8 Additional Explorations

9 Construction Considerations

9.1 Dewatering

9.2 Earthwork

9.2.1 Site Preparation

9.2.2 Excavation and Rippability

9.2.3 Temporary Slopes and Shoring

9.2.3.1 Temporary Slopes

9.2.3.2 Temporary Shoring

9.2.4 Foundation Subgrade Preparation

9.2.5 Fill Placement and Compaction

9.3 Pipeline and Manhole Considerations

9.3.1 Trench Excavation

9.3.2 Subgrade Preparation

9.3.3 Pipe and Manhole Bedding and Backfill

9.3.4 Pipe Trench and Manhole Backfill

9.4 Horizontal Directional Drilling (HDD)

9.4.1 Trenchless Construction

9.4.2 Anticipated Ground Conditions

9.4.3 Potential Risks

9.4.3.1 Inadvertent Drilling Fluid Release

9.4.3.2 Obstructions

10 Closure

11 References iv

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Exhibits Exhibit 4-1: Site Conditions in June 2022 during drilling at boring SW-15 Exhibit 5-1: Geologic Map of the Headquarters Site Exhibit 5-2: Geologic Map of the Swiftcurrent Site Exhibit 5-3: Summary of Groundwater Depths During Drilling Exhibit 6-1: Corrosivity Ratings Based on Soil Resistivity Exhibit 6-2: Corrosivity Ratings Based on Water Soluble Sulfate Exposure Exhibit 7-1: Seismic Design Parameters Exhibit 7-2: Recommended Lateral Earth Pressures Exhibit 9-1: Bedding and Embedment Material Gradation

Figures Figure 1: Vicinity Map Figure 2: Headquarters Site and Exploration Plan Figure 3: Swiftcurrent Site and Exploration Plan Figure 4: Recommended Surcharge Load for Temporary and Permanent Walls

Appendices Appendix A: Subsurface Explorations Appendix B: Laboratory Test Results Important Information

Utility Improvements Preliminary Geotechnical Report

107857-001 December 2022

1 INTRODUCTION

This preliminary geotechnical report presents the results of our geotechnical explorations and provides our preliminary geotechnical engineering recommendations for the Glacier National Park Headquarters Wastewater System Improvements (GLAC 307440), and the Swiftcurrent Water Distribution System Replacement Project (GLAC 307606) (the Project) in Flathead and Glacier Counties, Montana. Our work was completed in accordance with our signed Geotechnical Subconsultant Agreement Number 1000100068490 with HDR Engineering, Inc. (HDR).

Our activities under this scope of services included the following:

Completing geotechnical explorations within the two Project areas, Conducting laboratory testing on select soil/rock samples, and

Preparing this preliminary report, which summarizes the results of our explorations and laboratory testing and provides our preliminary geotechnical engineering recommendations for the proposed improvements.

If a service is not specifically indicated in this report, do not assume it was performed.

2 SITE DESCRIPTION

The Project is located at two sites: at the West Glacier Headquarters site in Flathead County and the Swiftcurrent area in Glacier County, Montana, inside Glacier National Park (the Park), (Figure 1).

2.1 Headquarters Site

The Headquarters site is located at 64 Grinnel Drive, West Glacier, in Flathead County, near the West Entrance to the Park. The Headquarters site is generally bordered to the north and west by Going-to-the-Sun Road, to the east by Belton Hills, and to the south by the Middle Fork Flathead River. The site is occupied by the Headquarters Building, residential housing and apartment buildings, maintenance facilities, and asphalt paved roadways (Figure 2).

The terrain with the Headquarters Site is relatively flat and sloped gently to the west.

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107857-001 December 2022

2.2 Swiftcurrent Site

The Swiftcurrent site is generally located approximately 25 miles northeast of the Headquarters site and ½ mile west of Swiftcurrent Ridge Lake, near the east side of the Park. The Swiftcurrent site is bordered to the south by Swiftcurrent Creek, to the west by Wilbur Creek, and to the north by Altyn Peak. The site is occupied by the Swiftcurrent Motor Inn and lodging area, the Many Glacier Campground, and a National Park Service (NPS) administrative area, with asphalt paved roadways throughout (Figure 3). A service road extends northwest from the loop road north of the Swiftcurrent Motor Inn to the location where the existing water storage tank is buried. Large boulders and rock outcrops are exposed at the surface near the tank site and along the service road. This location lies approximately 100 feet above the remainder of the site, which slopes gently to the south and east.

3 PROJECT DESCRIPTION

We based our understanding of the Project improvements on the HDR plans for the GLAC 307440 Headquarters Improvements and plans for the GLAC 307606 Swiftcurrent Improvements, dated March 2022. HDR is currently preparing design-build procurement documents for the Project and limited information was available for the planned final design and construction at the time we prepared our report.

3.1 GLAC 307440 Replace Headquarters Wastewater & Backup

Power Systems

The Project improvements will include a new sanitary sewer system to service the existing facilities at the Headquarters site. More than 8,700 feet of sanitary sewer pipeline will be installed via open trench construction methods, generally following the existing roadway alignments. The minimum depth of cover of the pipeline will be 7 feet. The sewer pipeline is expected to consist of 8-inch inside diameter (I.D.) Polyvinyl chloride (PVC) pipe. The sanitary sewer system will also include 57 manholes.

Trench cuts in asphalt paved roadways are expected to be patched with 6 inches of crushed base course and 3 inches of asphalt pavement.

Other improvements are expected to include mechanical improvements at the lift station building and a new backup generator at the Headquarters Building.

Utility Improvements Preliminary Geotechnical Report

107857-001 December 2022

3.2 GLAC 307606 Swiftcurrent Water Distribution System Improvements

The Project improvements at the Swiftcurrent site will include a new precast or cast-in-place concrete (CIP), below-grade water storage tank, with dimensions of approximately 17 feet by 17 feet (20,000 gallons). The proposed water storage tank will be located near the existing 40 by 40-foot (125,000 gallons) below-grade water storage tank at the north end of the site (see Figure 3).

More than 11,000 feet of water pipeline will be installed primarily via open trench construction methods. The new water pipeline will begin at the storage tank and flow south at grades ranging from < 1% to > 13%. The pipeline alignments will generally parallel the existing roadway alignments. The water pipeline is expected to consist of 6- to 10-inch I.D.

high-density polyethylene (HDPE) pipe. The water lines will be installed in trench excavations with a minimum embedment depth of 3 feet for seasonal (winterized) operations.

Trench cuts in asphalt paved roadways are expected to be patched with 6 inches of crushed base course and 3 inches of asphalt pavement.

While the majority of the water pipelines will be installed via open trench constructions, a relatively short section (~475 feet) of pipeline is expected to be installed by horizontal directional drilling (HDD) at the east end of the site in the picnic area to reduce surface disturbance and potential impacts to cultural resources. In addition, a new water well is planned in the administrative area at the east end of the site.

Other improvements are expected to include a new generator at the ranger station and mechanical improvements at the Chlorination Building.

4 FIELD EXPLORATIONS AND LABORATORY TESTING

Shannon & Wilson conducted a subsurface exploration program between June 6 and 9, 2022 to evaluate the subsurface conditions at the Headquarters and Swiftcurrent sites. The exploration program consisted of the following:

8 borings (SW-01 through SW-08) were completed at the Headquarters site, along the proposed sanitary sewer line alignments to depths of approximately 21.5 feet below ground surface (bgs), 8 borings (SW-09 through SW-16) were completed at the Swiftcurrent site. Borings SW- 10 through SW-15 were drilled along the proposed water line alignments to depths of

Utility Improvements Preliminary Geotechnical Report

107857-001 December 2022 approximately 11.5 feet bgs. Boring SW-09 was drilled to 77 feet bgs at the proposed water well location and boring SW-16 was drilled to a depth of 40 feet bgs for the proposed water storage tank.

The locations of the borings are shown on Figure 2. Exhibit 4-1 shows site conditions at boring SW-15 at the time of our field exploration program.

Exhibit 4-1: Site Conditions in June 2022 during drilling at boring SW-15 (view approximately southeast).

Appendix A describes the procedures used to complete the drilling and sampling of the geotechnical borings and presents the individual exploration logs along with an explanation of the symbols and terminology used on the logs.

We completed geotechnical laboratory testing to determine index and engineering properties of selected soil and rock samples retrieved from the borings. Laboratory tests included natural water content, moist unit weight, Atterberg limits, grain-size distribution, corrosion testing, Hveem Stabilometer (R-value), and unconfined compressive strength

Utility Improvements Preliminary Geotechnical Report

107857-001 December 2022

(UCS) on rock cores. Laboratory test methods and results are provided in Appendix B. The natural water contents, Atterberg limits, and fines content are also indicated on the individual boring logs in Appendix A.

5 GEOLOGIC SETTING AND SUBSURFACE CONDITIONS

We based our understanding of the geology and subsurface conditions at the site on regional geologic maps, our field reconnaissance, and the results of our field exploration program.

5.1 Regional Geology

Based on geologic mapping by Whipple (1992), the Project traverses multiple geologic units as described below and presented Exhibit 5-1 and Exhibit 5-2.

5.1.1 Headquarters Site

Alluvium (Qal) – Holocene-age deposits of gravel, sand, and silt in canyon bottoms.

Helena Formation (Yh) – middle Proterozoic-age, interbedded limestone, dolomite, and quartz arenite.

Empire Formation (Ye) – middle Proterozoic-age argillite and siltite with lesser amounts of arenite and dolomite.

N

Exhibit 5-1: Geologic Map of the Headquarters Site (adapted from Whipple, 1992) (not to scale)

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5.1.2 Swiftcurrent Site

Glacial and fluvioglacial deposits (Qg) – Holocene and upper Pleistocene age deposits of unsorted boulder rubble with lesser amounts of sand, silt, and clay (till).

Appekunny Formation (Yap) – middle Proterozoic-age, interlaminated siltite and argillite.

N

Exhibit 5-2: Geologic Map of the Swiftcurrent Site (adapted from Whipple, 1992) (not to scale)

5.2 Subsurface Conditions

The subsections below present summaries of the subsurface conditions encountered at each project location. Soil density and consistency and bedrock strength terminology are defined on Figure A-1 and A-2, respectively.

5.2.1 Headquarters Site

The overburden soils generally consisted of: (1) loose to medium dense, clayey/silty sand to poorly graded sand with clay/silt and gravel, and (2) medium dense to very dense, poorly graded gravel with clay/silt and sand (alluvium). Cobbles were inferred in the subsurface from drilling action in the borings. Bedrock was not encountered to the depths explored.

5.2.2 Swiftcurrent Site

The overburden soils generally consisted of: (1) poorly graded gravel with clay/silt and sand, and (2) clayey/silty sand with gravel (till). The soils were predominantly medium

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107857-001 December 2022 dense to very dense; however, very loose to loose deposits were encountered in four borings (SW-10, SW-11, SW-13, and SW-14).

Claystone and siltstone boulders were inferred in boring SW-09 from depths of approximately 29 to 38 feet bgs and 44 to 59 feet bgs, respectively. Siltite bedrock was encountered in boring SW-16 at a depth of 5.5 feet bgs; the upper 10 feet of bedrock was drilled by ODEX methods and described as weak to medium strong (see Figure A-2 for a definition of strength descriptions). NQ2 double tube wireline coring methods were used to advance the boring to a total depth of 40 feet. Laboratory test results indicate the core samples tested were very strong. Completely weathered siltstone bedrock was encountered in boring SW-15 at a depth of 9.5 feet.

5.3 Groundwater

As indicated in Exhibit 5-3, groundwater was measured in five borings during drilling at depths between 5 feet and 19 feet. Groundwater measurements were recorded using an electronic water level indicator.

Exhibit 5-3: Summary of Groundwater Depths During Drilling

Boring No.

Groundwater

Depth1 Measurement

Date

SW-01 19.0 6/9/2022

SW-09 16.9 6/7/2022

SW-10 8.2 6/8/2022

SW-13 5.3 6/8/2022

SW-15 6.1 6/8/2022

NOTES:

Depth values are in feet.

Groundwater fluctuations are possible and will depend on many factors, including seasonal variations, local precipitation, runoff, snow melt, and stage of the Middle Fork Flathead River, Swiftcurrent Creek, and Wilbur Creek.

5.4 Subsurface Variation

The explorations were performed to evaluate geotechnical soil and bedrock conditions at the Project sites. Our observations are specific to the locations, depths, and times noted on our boring logs and may not be applicable to all areas of the Project. No amount of exploration or testing can precisely predict the characteristics, quality, or distribution of subsurface and site conditions. Potential variation includes, but is not limited to:

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The conditions between explorations may be different.

The passage of time or intervening causes (natural and manmade) may result in changes to site and subsurface conditions.

Penetration test results in gravelly soils may be unrealistic. Actual soil relative density may be lower than estimated if the test was performed on gravel or cobbles.

6 GEOLOGIC HAZARD EVALUATION

6.1 Seismic Hazards

Based on geologic mapping, the nearest fault to the Project site is the South Fork Flathead Fault. The northern terminus of the mapped fault trace is shown approximately 2 miles south of the Headquarters site and approximately 27 miles southwest of the Swiftcurrent site (USGS, 2021 and Haller, 2006). Haller (2006) notes that the fault has not been studied in detail, but that no scarps (e.g., ground ruptures) have been identified along this fault, suggesting that there have not been movements on the fault in the Holocene (more recently than about 11,000 years before present). Other workers (Bryant and others, 1984 and Erdmann, 1944) concluded that there is no evidence of fault movements causing ground ruptures since the Tertiary Period (more than about 2.5 million years before present). In our opinion, the above sources suggest that the Project site is unlikely to be affected by ground ruptures related to fault movements.

Liquefaction can occur in loose, saturated, cohesionless soils when subjected to earthquake ground shaking. Seismic compression may occur when loose, granular soils above the groundwater table are rearranged into a tighter packing configuration during seismic shaking, which can cause settlement. Based on subsurface soil and groundwater conditions encountered in the borings, it is our opinion there is a risk of liquefaction and seismic compression along the pipeline alignment. The risk cannot be fully understood because most of the pipeline borings were only drilled to depths of 10 or 20 feet. However, the risk of liquefaction and seismic compression at the proposed water tank is nil because of the presence of shallow bedrock. NPS will need to determine if seismic hazards beneath the pipeline will need to be addressed during final design and, if so, provide direction as to what degree.

6.2 Corrosive Soil and Bedrock

The soil/rock encountered at the Project site can be corrosive to substructure elements. To assist in estimating the corrosion potential at the site, selected samples were tested for pH, Utility Improvements Preliminary Geotechnical Report

107857-001 December 2022 resistivity, water soluble sulfates, and chlorides. The results are presented in Table B-1 in Appendix B.

The resistivity measured in the samples was 2,200 to 3,800 ohm-centimeters. Based on correlations developed by Roberge (2012) as shown in Exhibit 6-1, these values suggest corrosive to highly corrosive subsurface conditions for metallic pipe in contact with subsurface materials across the site.

Exhibit 6-1: Corrosivity Ratings Based on Soil Resistivity

Soil Resistivity (ohm-cm)

Corrosivity Rating

>20,000 Essentially Noncorrosive

10,000-20,000 Mildly Corrosive

5,000-10,000 Moderately Corrosive

3,000-5,000 Corrosive

1,000-3,000 Highly Corrosive

<1,000 Extremely Corrosive

The concentration of water-soluble sulfates measured in the samples was 0.02% by weight.

Based on classifications as defined by ACI-318-19 (ACI, 2019) as shown in Exhibit 6-2, these test results suggest an exposure class S0 on concrete exposed to site soils.

Exhibit 6-2: Corrosivity Ratings Based on Water Soluble Sulfate Exposure

Water Soluble Sulfate in Soil (Percent by Weight)

Sulfate Severity (Class)

<0.10 Negligible (S0)

0.10-<0.20 Moderate (S1)

0.20-2.00 Severe (S2)

>2.00 Very Severe (S3)

The test results and the above discussion are provided to assist the designer in the selection of project materials, concrete type, or other features with respect to corrosion. As appropriate, the designer should consider protective measures, such as coatings, upsizing for section loss, or using alternative materials to reduce the corrosion potential.

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7 PRELIMINARY GEOTECHNICAL ENGINEERING

RECOMMENDATIONS

The preliminary recommendations presented in the following sections are based on our understanding of the Project based on information provided by HDR and our subsurface exploration and laboratory testing program.

7.1 Seismic Design Considerations

We understand that design ground motion parameters will be based on the requirements of the 2021 International Building Code (International Code Council, 2020), which has adopted the ASCE 7-16 design code for minimum design loads on buildings (ASCE, 2017). These design loads are in turn based on the USGS National Seismic Hazard Maps that were updated in 2008 (Petersen and others, 2008). Based on the soil and rock conditions encountered at the water storage tank location, the site can best be described as Site Class A (hard rock). The following exhibit provides seismic design parameters for the Project.

Exhibit 7-1: Seismic Design Parameters

Design Parameter Value

Peak Ground Acceleration (PGAB)¹ 0.183 g

Short-period Spectral Acceleration, SS 0.4 g

Long-period Spectral Acceleration, S1 0.127 g

Site Class A

Site Factor, FPGA 0.8

Site Factor, Fa 0.8

Site Factor, Fv 0.8

Site Modified Peak Ground Acceleration, PGAm 0.146 g

Site Modified Spectral Acceleration (0.2 s), SMS 0.320g

Site Modified Spectral Acceleration (1.0 s), SM1 0.102 g

Seismic Design Value (0.2 s), SDS 0.214 g

Seismic Design Value (1.0 s), SD1 0.068 g

NOTES:

PGAB refers to peak ground acceleration for a site underlain by Site Class B soil (rock).

g = gravity; sec. = seconds

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7.2 Below Grade Water Tank

7.2.1 Foundations

The proposed 20,000-gallon water storage tank is expected to be a buried structure bearing at depth of approximately 15 to 20 feet bgs. A mat foundation is suitable for the water storage tank. We anticipate that the tank will be bearing on siltite bedrock and will essentially fully compensated (i.e., the weight of the structure will be less than the excavated soil/rock). Therefore, we anticipate only nominal settlement to occur (less than approximately ½ inch).

Allowable bearing capacity for the mat foundation will be high because of the presence of rock and should not control the design. For preliminary design of the mat foundation, we recommend using an allowable service bearing pressure of 10,000 pounds per square foot (psf), which corresponds to estimated total settlement of 1 inch, or a service bearing pressure of 5,000 psf, with an estimated total settlement of 0.5 inches. These values assume a 17-foot square water tank. Settlement should occur essentially as load is applied.

7.2.2 Lateral Earth Pressures

The lateral earth pressures on structure walls depend on many factors, including surcharge loads, the soil type, excavation extents and backfill type, and whether the top of the wall can yield or deflect laterally during and after excavation. If the top of the wall is free to yield a minimum of 0.1% of the wall height (i.e., 0.001 times the height [H]), the soil pressures will generally be lower (i.e., active condition), than if the wall is not able to yield this amount due to stiffness or resistance of the wall (i.e., at-rest condition). We anticipate that at-rest earth pressures will be appropriate for the buried tank.

For preliminary design purposes, we assumed that the tank will be excavated such that a 1H:1V (horizontal to vertical) zone extending upward from the base of the structure from a point 1.5 feet behind the wall zone will need to be backfilled. We further assumed that the overburden soils encountered in boring SW-16 (silty gravel with sand with any cobbles and boulders removed) would be used as backfill and that water does not accumulate in the backfill. Excavated rock should not be used for backfill. Exhibit 7-2 provides recommended lateral earth pressures values for these conditions. These pressures also assume a vertical wall face and a flat backslope.

Seismic active lateral earth pressure coefficients were determined based on the Mononabe- Okabe method (AASHTO, 2020), and seismic at-rest earth pressure coefficients were determined based on methods developed by Zhang and others (1998). Per AASHTO (2020), Utility Improvements Preliminary Geotechnical Report

107857-001 December 2022 the pressure distribution shape for dynamic active earth pressures is triangular, with the resultant force (PAE) acting at the lower third of the wall height (h/3). The parameters are provided in Exhibit 7-2.

Exhibit 7-2: Recommended Lateral Earth Pressures

Design Parameter Coefficient Equivalent Fluid Density (pcf)

Static At-Rest Earth Pressure Coefficient, ko 0.44 60

Dynamic At-Rest Earth Pressure Coefficient, koe 0.51 68

NOTES:

Based on granular soil with an assumed unit weight of 135 pcf and a friction angle of 34 degrees for the retained soil.

Values assume a vertical face and flat backslope.

pcf = pounds per cubic foot

Surcharge loads from motor vehicles/traffic and construction equipment will induce additional lateral loads on structure walls. The pressures provided above do not account for surcharge loads. Lateral loads due to various types of surcharges may be calculated by multiplying the surcharge by the at-rest earth pressure coefficient (k0). Surcharge loads should be applied as recommended in Figure 4.

The values in Exhibit 7-2 could be significantly reduced if the excavation for the tank is less than the assumed 1H:1V zone assumed in developing the above values.

7.2.3 Lateral Resistance

Lateral loads can be resisted by friction along the base of the foundation using an allowable coefficient of sliding resistance of 0.3 for concrete sliding on siltite bedrock. This allowable value for coefficient of sliding resistance includes a factor of safety of 1.5.

7.2.4 Drainage

As indicated in Section 7.2.2, we assume that groundwater will not accumulate in the backfill around the tank. Groundwater was not encountered while drilling in boring SW-16, near the proposed water storage tank. As such, groundwater is not anticipated to impact design of the structure. However, surface water from rainfall and snowmelt can make its way into the backfill materials and result in increased pressure on walls and potential uplift conditions. As such, we recommend that the design-build contractor consider this potential in the design and either account for the potential for saturation of backfill to result in higher lateral pressures/uplift, provide for subsurface drainage, or take measures to prevent the infiltration of surface water into backfill materials.

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7.3 Pipelines and Manholes

We anticipate that foundation soils at pipeline invert elevations will consist of primarily granular overburden soils with varying amounts of silt and clay. Based on the Project descriptions presented in Section 3 of this report, bedrock is not expected to be encountered in the trench excavations at both Project areas (except near the proposed water tank).

Groundwater is not expected to be encountered at the Headquarters site, but it may be within a foot or two below the bottom of trench in portions of the Swiftcurrent site, which could result in unstable trench subgrade.

7.3.1 Loads on Pipes

The structural design of the pipeline should consider the loads acting on the pipe. The earth load that will be imposed on a buried pipe depends on the subsurface soil and groundwater conditions, the type of backfill, the height of backfill above the pipe, the method of installation, the relative rigidity of the pipe, and the pipe dimensions. Because the proposed pipeline across the alignment is flexible pipe (PVC or HDPE) we anticipate that the loading will be transferred through the pipe and carried by the bedding and subgrade soils beneath the pipe.

Loads on flexible pipes are supported by the passive resistance of the soil as the pipe deflects and the sides move outward and downward into the soil. To estimate the potential settlement of flexible pipes under loading, the Modified Iowa Formula (ASCE and Water Pollution Control Federation, 1982) is typically used. The soil parameter required in this formula is the modulus of subgrade reaction (E’). Based on the recommendations made in the American Water Works Association (AWWA) PVC Pipe Design and Installation Manual (AWWA, 2002) and the AWWA’s PE Pipe – Design and Installation Manual (AWWA, 2006), we recommend a modulus of soil reaction (E') of 3,000 psi for slightly compact granular soils and 5,000 psi for compact granular soil.

7.3.2 Thrust Restraint

Thrust restraint for the pipelines may be provided through the use of restrained joints or thrust blocks. Thrust blocks bearing against the native soils and used to encase tee connections and bends may be designed using an allowable passive earth pressure of 375 pcf, with an average pressure over the face of the thrust block not to exceed 2,000 psf. For restrained joints, a coefficient of friction of 0.25 may be used between the pipe and pipe bedding material in combination with a soil unit weight of 125 pcf. These values include a factor of safety of 1.5 on ultimate soil strengths.

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7.3.3 Manhole Foundations

We recommend the use of a structural mat (raft) foundation for manholes. We recommend a gross allowable bearing capacity of 1,500 psf for soil or overburden and 2,000 psf for bedrock. Settlement of the manholes is anticipated to be about ½ inch. The at-rest earth pressures provided in Section 7.2.2 can be used for manhole design. Uplift pressure on manhole foundations should be considered at the Swiftcurrent site based on the relatively shallower groundwater conditions encountered in the borings during drilling. Because a long-term groundwater monitoring system was not completed as part of the Project, we recommend assuming a groundwater level at the ground surface for this evaluation.

Sufficient mass or uplift resistance will be required to counteract uplift loads created by hydrostatic forces acting on the bottom of the foundation.