16-008_Geotech_Report.pdf

i

GEOTECHNICAL REPORT

GEOTECHNICAL REPORT FOR:

U.S. Fish and Wildlife Service Red Rock Lakes National Wildlife Refuge

Bridge

Lima, Montana

May 2016

Project 16-048

TABLE OF CONTENTS

INTRODUCTION AND PROJECT DESCRIPTION

SCOPE OF WORK

GEOLOGY

Geology of the Upper Red Rock Lakes Area

Geology of the Site

EXPLORATIONS AND SUBSURFACE CONDITIONS

Subsurface Explorations

Subsurface Conditions

GEOTECHNICAL RECOMMENDATIONS

Foundation Design

Option 1

Option 2

Recommended Foundation Bearing Pressures

Lateral Earth Pressures

Seismic Design Factors

FOUNDATION-RELATED FILL MATERIAL RECOMMENDATIONS

Re-use of Embankement Fill

Structural Fill

Rock Backfill

Road Mix Gravel for Culver Road

FILL PLACEMENT AND COMPACTION

COLD/WINTER WEATHER CONSTRUCTION

LIMITATIONS

REFERENCES

List of Figures

Figure 1 – Vicinity Map 1

Figure 2 – Vicinity Map 2

Figure 3 – Geology Map

Figure 4 – Approximate Borehole Locations

Figure 5 – Option 1 Foundation Detail

Figure 6 – Option 2 Foundation Detail

List of Appendices

Appendix A – Boring Logs

Appendix B – Laboratory Testing

Appendix C – USGS Earthquake Design Spectral Response

Appendix D – Photographs

Appendix E – Limitations of Your Geotechincal Report

INTRODUCTION AND PROJECT DESCRIPTION

This report presents our geotechnical assessment for the U.S. Fish and Wildlife Service (FWS) proposed bridge installation project over Elk Springs Creek in Red Rock Lakes National Wildlife

Refuge. The information contained herein is based on an investigation and analysis of the site’s subsurface conditions, a review of geologic maps and literature for the project area, and previous experience gained during our involvement with other similar projects.

Red Rock Lakes National Wildlife Refuge is located in the high-elevation Centennial Valley in southwestern Montana approximately 25 miles west of West Yellowstone, Montana. Two separate spring channels converge about 650 feet above the old Culver Road Crossing (site of the proposed bridge), which form the headwaters of Elk Springs Creek. Elk Springs Creek is generally wide (relative to its depth) with a gentle stream bed slope as it flows southwest from

Swan Lake and eventually into Red Rock Lakes. Significant wetland and riparian areas abut the stream along nearly the entire stretch from the headwaters to its outlet at Swan Lake. Please refer to Appendix D for photographs of the project site.

We understand from the report prepared by Dominick (2015) that this work is part of a much larger project to restore approximately 3,500 feet of Elk Springs Creek and provide suitable spawning habitat for Arctic Grayling. In 1954, much of the creek’s historic drainage was impounded by an earthen dam (MacDonald Pond) in an effort to create waterfowl open water habitat. This impoundment was located just southwest of the Culver Road Crossing.

In an effort to restore suitable spawning habitat in Elk Springs Creek, the NWR drained

MacDonald Pond as well as a second impoundment (Buck Pond) in 2009 and 2010, respectively.

In 2011, they removed the Culver Road Culvert Crossing from Elk Springs Creek. However, we understand that the accumulation of lake deposits (primarily silt and fine sand) from the former impoundments pose a challenge to restore the Arctic Grayling spawning habitat through this reach.

The goal of this project is therefore to re-establish a more natural stream morphology by narrowing and deepening the current creek. Narrowing will be accomplished by removing

Matt Shafer May 27, 2016

USFWS Red Rock Lakes NWR Bridge

Allied Engineering Services, Inc. Page 2 accumulated silt/sand from the active channel and building new narrower bank margins using this material in combination with wetland sod taken from on-site borrow areas. Narrowing the channel will help increase stream velocity, hence aid in removing the deposited sand and silt and ultimately creating habitat for fish.

The intent of this portion of the project is to replace the former Culver Road Culvert Crossing with a bridge to be re-located from another location. The bridge consists of a pre-engineered steel beam structure with a concrete deck. The bridge will be a single span measuring approximately 20 feet wide by 38 feet in length and supported on pre-cast concrete sills/abutments at each end.

SCOPE OF WORK

Our Scope of Services for this project included:

Drilling of 2 boreholes (one at each abutment location).

Laboratory testing of select soil samples.

Providing foundation support options and allowable lateral and vertical bearing criteria as well as associated anticipated settlements.

Site-specific seismic classification and analysis.

Backfill material and compaction recommendations.

General site earthwork and construction recommendations.

The results of the above scope of work are summarized in this geotechnical report. The purpose of the report is to inform the U.S. Fish and Wildlife Service of the subsurface conditions underlying the site; and to present geotechnical recommendations for consideration and implementation during the planning, design, and construction of the bridge.

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GEOLOGY

Geology of the Upper Red Rock Lakes Area (from Pierce et al, 2014)

In general, the surficial geology of the Upper Red Rock Lakes region is comprised of deposited sediment from the surrounding Centennial Valley. Originally, the Centennial Valley drained to the northeast through a series of lakes (starting with Elk Lake). Later, landslides blocked and dammed the drainage just above Elk Lake, which created glacial Lake Centennial. Fine-grain sediments deposited in Lake Centennial now cover much of the valley floor and overlie the more coarse grained sand and gravel that were deposited prior to the damming of the valley.

As Lake Centennial lowered over time to the elevation of the present day Upper and Lower Red

Rock Lakes, low-energy streams brought fine-grain alluvial sediments down to the valley floor and in some instances covered the older lake deposits. In addition, eolian or windblown deposits of fine sand carried from the west and south were deposited on the northern side of the valley. Early Pleistocene deposits of basalt and tuff (pre-date Lake Centennial) are also present to the north and east of the proposed bridge site.

Geology of the Site

According to the “Geologic Map of the Southern Part of the Upper Red Rock Lake Quadrangle, Southwestern Montana and Adjacent Idaho” prepared by Witkind (1976), the proposed bridge site is mapped as alluvial deposits (Qal). These more recent alluvial deposits likely cover the original Centennial Lake Deposits which are mapped just to the west of the site. Our observations from the borings are consistent with the mapped geology.

EXPLORATIONS AND SUBSURFACE CONDITIONS

Subsurface Explorations

Subsurface conditions were investigated on May 3, 2016 by Ron Orton with Allied Engineering

Services Inc., under the direction of Craig Madson, PE – Principal Geotechnical Engineer. A total of two soil boring explorations (SB-1 and SB-2) were drilled on the site using a Mobile B-61 drill rig provided by O’Keefe Drilling of Butte, Montana. One boring was completed at each abutment location in the existing road embankment. Each boring was completed to a depth of approximately 20.5 feet. Standard Penetration Testing was performed at regular intervals to gather samples and to determine the consistency of the soil. A Standard Penetration Test (SPT) involves driving a 2-inch diameter split spoon sampler in 6-inch increments (18 inches total)

Allied Engineering Services, Inc. Page 4 using a 140 pound hammer dropped 30 inches. The number of blows required to drive the sampler each of the 6-inch increments are recorded and the last two increments are added to determine the “N value” which can be correlated to a number of other soil characteristics.

During the explorations, soil and groundwater conditions were visually characterized, measured, and logged. Copies of our borehole logs are attached. Each of these logs provides assorted field information, such as soil depths and descriptions, groundwater conditions, and a sketch of the soil stratigraphy. Please be aware that the detail provided on the logs cannot be accurately summarized in a paragraph; therefore, it is important to review the logs in conjunction with this report. Following completion of the fieldwork, the borehole locations were backfilled and cleaned up to the extent possible.

Subsurface Conditions

As noted earlier, both boreholes were located within the existing road embankment. Following is a general description of the subsurface conditions encountered:

Crushed Road Mix: In both soil borings, the upper 6 to 8 inches generally consisted of a crushed road mix gravel from the existing road. The road mix was medium dense, sandy gravel that was slightly moist.

Embankment Fill: Approximately 6.0 to 6.5 feet of road embankment fill was encountered in

SB-1 and SB-2. This material consisted of a mixture of loose to medium dense, brown to dark brown, sand with silt, gravel and some cobbles. Small pockets of organics intermixed with the embankment fill were also found.

Buried Wetland (Native Organic Topsoil): In both soil borings, a layer of very moist, loose to medium dense, fine sand with organics was encountered at approximately the 6.0 to 7.0 foot depth. The color ranged from gray to very dark brown. This material is the original organic topsoil layer prior to the placement of the embankment for Culver Road. In SB-1 the organics were about 12 inches thick while in SB-2, the organics were closer to 20 inches thick.

Alluvial and Lacustrine Deposits: Underlying the original organic topsoil were the native mapped alluvial and lacustrine deposits. This material generally consisted of very moist to wet, medium dense, silty sand with seams of sandy silt and fine sand. In SB-1, this material was encountered starting at 7.0 feet and extended to the bottom of the borehole at 20.5 feet.

Pockets of heaving sand were found at the 14.0 to 15.0 foot depth and at 17.0 feet. In SB-2, the

Allied Engineering Services, Inc. Page 5 underlying alluvial and lacustrine deposits were encountered starting at 8.2 feet and extended to the bottom of the borehole (20.5 feet). Pockets of heaving sand were found at 14.0 feet in

SB-2.

Groundwater

Groundwater was encountered at both soil boring locations. In SB-1, groundwater was found at a depth of about 8.5 feet and at 8.9 feet in SB-2. These observations were made in May of 2016 and are likely subject to change seasonally.

GEOTECHNICAL RECOMMENDATIONS

Foundation Design

We understand the intent of the bridge is to enable traffic to cross Elk Springs Creek. A description of the bridge was provided earlier.

In this report, we have proposed two foundation design options to support the bridge for consideration by the U.S. Fish and Wildlife Service (FWS). Both options consider the remoteness of the site and associated difficulties with transporting materials and equipment to the site. Please refer to the attached foundation details for both options.

Option 1

Option 1 is summarized in Figure 5 attached. Under this option, we propose to re-use the embankment fill as a structural fill. During our explorations, we generally found this material to be in a relatively loose state. Therefore, we recommend excavating through the embankment fill and native organic wetland soils down to the native materials. Assuming the moisture content of the embankment fill materials is near optimum, we propose to compact this material in controlled lifts to 97 percent of its Standard Proctor density based on ASTM D-698 back up to the elevation of the concrete sill/abutment. Please note that some drying of this material may be required depending on moisture content. The reuse of organics should be avoided. If possible, we suggest compacting the subgrade prior to the placement of the fill.

If groundwater or wet conditions are encountered at the bottom of the excavation, a layer of 6-inch diameter angular rock (non-moisture sensitive material) may be used to bring the excavation up to where the on-site materials may be used. If rock is placed, we suggest lining

Allied Engineering Services, Inc. Page 6 the trench and covering the rock with an 8-ounce non-woven geotextile separator fabric to prevent the overlying materials or soils on the side from being washed into the rock.

The minimum width of the trench at the base should be the width of the concrete sill plus the depth down to the target bearing below the bottom of the sill. For instance, if the sill width is

1.5 feet and the depth to the native target bearing soils is 6 feet measured from the bottom of the sill, the trench should be 7.5 feet wide at the base. This width will allow the load transfer to take place completely within the structural fill. The sill should be centered on the trench width.

If there is any potential for scour, we suggest covering the banks above the estimated water level with an 8-ounce non-woven geotextile separator fabric and angular rock with a D50 of 6 inches. We further suggest the rock be keyed into a trench back from the edge of the stream to a point of 1 foot below the design bed elevation of the stream or to the anticipated scour depth

(whichever is deeper). To avoid impacts to the Artic Grayling, no rock would be placed on the stream banks below the estimated water level as depicted in Figure 5. The intent of the rock would be solely to protect the bridge from scour in the event of a significant flood event. The

6-inch rock we depicted is an estimate only and we suggest the potential for scour be further evaluated.

Please recognize that Figure 5 is a schematic only and the final configuration will be dependent on the final design of the bridge.

Option 2

A second option to support the bridge (as shown on Figure 6) is to excavate down through the road fill and native organic soils to the underlying alluvial soils (target bearing). The trench would be lined with an 8-ounce non-woven geotextile separator fabric to prevent fines infiltration from the surrounding soils and then filled with angular rock with a D50 of 6 inches.

The rock should be placed in lifts and compacted with the bucket of the excavator. Again, the minimum trench width would be the width of the concrete sill plus the distance from the bottom of the sill to the target bearing soils measured to the bottom of the excavation. If possible, we suggest compacting the native subgrade prior to the placement of the rock. The sill should be centered on the trench width.

The advantage of this option is that the trench of rock will also serve dually to protect against scour in the event of flooding. Again, the D50 of the rock is an estimate only and we suggest a scour analysis to confirm the appropriate rock sizing.

Allied Engineering Services, Inc. Page 7

Recommended Foundation Bearing Pressures

As long as the above abutment foundation support recommendations are followed, we recommend using a bearing pressure for the foundation design of 3,500 pounds per square foot

(psf). The recommendation is applicable to either option assuming the over-excavation is completed as shown in Figures 5 and 6 as described earlier. We estimate the above referenced bearing pressure will result in total settlement of less than 1-inch.

Surface drainage should be directed away from the concrete sills in all directions.

Lateral Earth Pressures

The allowable lateral earth pressures against structures can be assumed to have an equivalent fluid pressure of 65 pounds per cubic foot (pcf) for an “at rest” soil condition. An “active” equivalent fluid pressure can be assumed to be 45 pcf provided slight outward movement of the structure occurs. The lateral earth loads provided are for static conditions and should be factored appropriately to represent lateral earth pressures during seismic events. Lateral forces from wind, seismic loadings, or from earth pressures will be resisted by passive earth pressure against the buried portions of the structure (concrete sills) and by friction against the bottom. Passive earth pressures in compacted backfill can be assumed to have a maximum equivalent fluid pressure of 280 pcf.

We recommend that a coefficient of friction of 0.35 be used between the concrete sill and the underlying structural fill or rock. Actual foundation loads (not factored or allowable loads) should be used in calculating frictional resistance to sliding at the base. The above values have no built in factor of safety, so an appropriate factor of safety for each particular load case should be used in all subsequent calculations.

Seismic Design Factors

Site-specific seismic design factors for the Red Rock Lakes area were found utilizing the USGS

Seismic Design Maps. This report is provided in Appendix C. Based on our on-site explorations and knowledge of the underlying geology, the site class for the project site should be considered to be Site Class D. The site-specific recommended response spectrum that encompasses the expected range of ground motions at the site has the following IBC design coefficients:

Allied Engineering Services, Inc. Page 8

Ss = 1.626 S1 = 0.483

SMS = 1.626 SM1 = 0.733

SDS = 1.084 SD1 = 0.488

FOUNDATION-RELATED FILL MATERIAL RECOMMENDATIONS

Re-use of Embankment Fill

To minimize import of material to the site, we believe the existing road embankment fill found on site can be re-used as structural fill under the abutments (for Option 1) assuming this material can be properly compacted. Any organics found in the fill should be separated. Some drying may be required depending on the moisture content. However, we believe this material will generally dry quickly given its relatively granular composition.

Structural Fill

Any granular structural fill needed for the project should consist of organic free, well-graded 3-inch minus uncrushed gravel or 1.5-inch minus crushed road mix gravel. The gravel courses shall meet the material and gradation specifications as presented in the Montana Public Works

Standard Specifications (MPWSS) for sub-base course and base course gravel.

Rock Backfill

Rock used for the trench backfill to support the concrete abutments/sills (for Option 2) should consist of angular rock. The rock can also be used to protect the stream banks against scour and erosion as discussed earlier. The rock should be angular with a D50 of 6 inches (or as deemed necessary for scour protection) and be resistant to weathering and water action. The minimum unit weight of the rock shall be 155 pounds per cubic foot (pcf).

Road Mix Gravel for Culver Road

We anticipate some crushed road mix gravel will be required for the completion of the approaches to the bridge. We suggest the use of 1.5 inch minus crushed gravel meeting the

Montana Public Works Standard Specification for base course gravel. We recommend a minimum of 12 inches of crushed road mix compacted to 95 percent of its Standard Proctor

Density based on ASTM D-698.

Allied Engineering Services, Inc. Page 9

FILL PLACEMENT AND COMPACTION

All fill materials should be placed in uniform, horizontal lifts and compacted to an unyielding condition. The “loose” thickness of each layer of fill prior to compaction should not exceed 12 inches for self-propelled rollers, 8 inches for remote-controlled trench rollers, and 6 inches for plate compactors. The moisture content of any fill material to be compacted should be within 2 percent of its optimum value. Provided in Table 1 below are compaction recommendations for general site applications. These recommendations apply to all fill materials and are presented as a percentage of the maximum dry density of the material being placed as defined by ASTM

D-698.

Table 1. Compaction Recommendations (Application vs. Percent Compaction).

APPLICATION % COMPACTION

Reuse of Road Embankment Fill for General

Grading and Road Mix Gravel for Culver Road

Reuse of Road Embankment Fill Under the

Concrete Sill supporting the Bridge Deck

Rock in the Trench Under the Concrete Sill Compaction with Excavator Bucket

COLD/WINTER WEATHER CONSTRUCTION

If construction will occur during the cold/winter weather season, the Contractor shall take all necessary precautions to prevent the earthwork from freezing and/or from being contaminated with snow. Exposed subgrade and fill materials should be adequately covered with concrete insulation blankets to prevent frost penetration and to protect them from snow. All soils that are used for fill under or around the concrete sills should be relatively dry, free of intermixed snow and frozen clods, and must not be placed when it is snowing. Fill materials to be placed under the concrete sills supporting the bridge should not be placed over frozen soils, which may be in a “frost-heaved condition”, or layers of snow.

When earthwork will proceed during the non-optimal times of the year, we recommend that it be performed in an expeditious manner; thereby minimizing the time that the foundation excavation is open and exposed to the elements. In addition, positive drainage must be established away from the excavation in order to prevent the entry of surface water runoff and the saturation of the underlying soils. Please be aware that carelessness with respect to any of

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REFERENCES

1. Dominick, D., (2015). “Elk Springs Creek Geomorphic Reconnaissance Report” by Point Bar Resources, LLC.

2. International Code Council, 2012. “International Building Code”.

3. Irving I.J., 1976 “Geologic Map of the Southern Part of the Upper Red Rock Lake Quadrangle, Southwestern Montana and Adjacent Idaho”, U.S. Geological Survey, Denver, CO.

4. Montana Contractors Association, April 2010. “Montana Public Works Standard

Specifications”, Sixth Edition.

5. Pierce K.L., Chelsey-Preston, T.L., and Sojda, R.L., 2014. “Surficial Geologic Map of the Red Rock Lakes Area, Southwest Montana”. U.S. Geological Survey Open-File Report 2014-1157, 22 p., scale 1:24,000, http://dx.doi.org/10.3133/ofr20141157

P:\2016\16-048 FWS Red Rock Lakes NWR Bridge\05 Design\Geotech\Report\FWS Red Rock Lakes NWR Bridge Geotech Report.docx

LIST OF FIGURES

FFiigguurree 11 –– VViicciinniittyy MMaapp 11

FFiigguurree 22 –– VViicciinniittyy MMaapp 22

FFiigguurree 33 –– GGeeoollooggyy MMaapp

FFiigguurree 44 –– AApppprrooxxiimmaattee BBoorreehhoollee LLooccaattiioonnss

FFiigguurree 55 –– OOppttiioonn 11 FFoouunnddaattiioonn DDeettaaiill

FFiigguurree 66 –– OOppttiioonn 22 FFoouunnddaattiioonn DDeettaaiill

FIGURECivil Engineering

Geotechnical Engineering

Land Surveying

32 DISCOVERY DRIVE . BOZEMAN, MT 59718

PHONE (406) 582-0221 . FAX (406) 582-5770

www.alliedengineering.com

FWR RED ROCK LAKES NWR BRIDGE

VICINITY MAP 1

WEST YELLOWSTONE, MT

Miles

N

Land Surveying

32 DISCOVERY DRIVE . BOZEMAN, MT 59718

PHONE (406) 582-0221 . FAX (406) 582-5770

www.alliedengineering.com

FWS RED ROCK LAKES NWR BRIDGE

VICINITY MAP 2

WEST YELLOWSTONE, MT

N Feet

Land Surveying

32 DISCOVERY DRIVE . BOZEMAN, MT 59718

PHONE (406) 582-0221 . FAX (406) 582-5770

www.alliedengineering.com

FWS RED ROCK LAKES NWR BRIDGE

GEOLOGY MAP

WEST YELLOWSTONE, MT

N

Land Surveying

32 DISCOVERY DRIVE . BOZEMAN, MT 59718

PHONE (406) 582-0221 . FAX (406) 582-5770

www.alliedengineering.com

FWS RED ROCK LAKES NWR BRIDGE

APPROXIMATE BOREHOLE LOCATIONS

WEST YELLOWSTONE, MT.

NFeet

SB-1

SB-2

Civil Engineering

Land Surveying

32 DISCOVERY DRIVE

BOZEMAN, MT 59718

PHONE (406) 582-0221

FAX (406) 582-5770

www.alliedengineering.com

FIGURE

FWS RED ROCK LAKES NWR BRIDGE

OPTION 1 FOUNDATION DETAIL

RED ROCK LAKES, MT

RED ROCK LAKES BRIDGE

Civil Engineering

Land Surveying

32 DISCOVERY DRIVE

BOZEMAN, MT 59718

PHONE (406) 582-0221

FAX (406) 582-5770

www.alliedengineering.com

FIGURE

FWS RED ROCK LAKES NWR BRIDGE

OPTION 2 FOUNDATION DETAIL

RED ROCK LAKES, MT

RED ROCK LAKES BRIDGE

LIST OF APPENDICES

AAppppeennddiixx AA –– BBoorriinngg LLooggss

AAppppeennddiixx BB –– LLaabboorraattoorryy TTeessttiinngg

AAppppeennddiixx CC –– UUSSGGSS EEaarrtthhqquuaakkee DDeessiiggnn SSppeeccttrraall RReessppoonnssee

AAppppeennddiixx DD –– PPhhoottooggrraapphhss

AAppppeennddiixx EE –– LLiimmiittaattiioonnss ooff YYoouurr GGeeootteecchhnniiccaall RReeppoorrtt

APPENDIX A

BBoorriinngg LLooggss

16-048 5/3/2015 1 of 1SB-1

Refer to Site Map

NA 20.5'

8" HSA/Std 140lb/Split Spoon

Steve from O'Keefe Drilling (Butte, MT) RCO, AESI (Bozeman, MT)

D E

P T

H

F

T

G E

O L

O G

I C

L O

G

DESCRIPTION OF MATERIALS

S A

M P

L E

S

N

U

N C

O R

B L

O W

S F

T

M O

I S

T U

R E

C O

N T

E N

T

OTHER FIELD OR

SAMPLE INFORMATION

10.0

20.0

30.0

32 DISCOVERY DRIVE

BOZEMAN, MT 59718

FAX (406) 582-5770

PHONE (406) 582-0221

Red Rock Lakes NWR

(Culver Bridge), MT.

Mobile B-61

8.5'

S1-A @

0.0' - 1.5'

(SSS)

7.4%

{0.0' - 0.7'}: (Road Mix)

Medium dense; brown; sandy

GRAVEL; slightly moist.

Notes:

- SSS - 2.0'' O.D. Split Spoon

Sample

- The beginning and ending depths of the individual soil layers are approximate.

LOG OF BORING

{0.7' - 1.3'}: (Embankment Fill)

Medium dense; dark brown; silty

SAND; slightly moist.

{1.3' - 1.6'}: (Embankment Fill)

Loose to medium dense; dark brown; cobbley SAND with gravel;

slightly moist.

{1.6' - 6.0'}: (Embankment Fill)

Loose to medium dense; brown;

sandy SILT with gravel; moist to very moist with depth.

{6.0' - 7.0'}: (Buried Wetland)

Loose; dark brown; fine SAND and sandy SILT with organics; moist.

{7.0' - 20.5'}: (Alluvium)

Medium dense; tan to brown;

SAND with seams of brown to dark brown silty fine SAND or fine sandy

SILT; very moist to saturated.

S1-B @

2.0' - 3.5'

(SSS)

S1-C @

4.0' - 5.5'

(SSS)

S1-D @

7.0' - 8.5'

(SSS)

S1-E @

10.0' - 11.5'

(SSS)

S1-F @

12.0' - 13.5'

(SSS)

S1-G @

14.0' - 15.5'

(SSS)

S1-H @

17.0' - 18.5'

(SSS)

11.2%

15.3%

24.4%

30.8%

21.3%

24.1%

S1-I @

19.0' - 20.5'

(SSS)

Very moist from 4.0' to

6.0'

Moist to 7.0' then very moist to wet

Groundwater at 8.5'

Heaving sand at 14.0' to

15.0'

Heaving sand at 17.0'

21.3%

22.3%

16-048 5/3/2015 1 of 1SB-2

Refer to Site Map

NA 20.5'

8" HSA/Std 140lb/Split Spoon

Steve from O'Keefe Drilling (Butte, MT) RCO, AESI (Bozeman, MT)

D E

P T

H

F

T

G E

O L

O G

I C

L O

G

DESCRIPTION OF MATERIALS

S A

M P

L E

S

N

U

N C

O R

B L

O W

S F

T

M O

I S

T U

R E

C O

N T

E N

T

OTHER FIELD OR

SAMPLE INFORMATION

10.0

20.0

30.0

32 DISCOVERY DRIVE

BOZEMAN, MT 59718

FAX (406) 582-5770

PHONE (406) 582-0221

Red Rock Lakes NWR

(Culver Bridge), MT.

Mobile B-61

8.9'

S2-A @

0.0' - 1.5'

(SSS)

33.4%

25.2%

10.4%

{0.0' - 0.5'}: (Road Mix)

Medium dense; brown; sandy

GRAVEL; slightly moist.

Notes:

- SSS - 2.0'' O.D. Split Spoon

Sample

- The beginning and ending depths of the individual soil layers are approximate.

LOG OF BORING

{0.5' - 3.5'}: (Embankment Fill)

Loose to medium dense; brown to dark brown; gravelly SAND with angular limestone cobble; slightly moist.

S2-I @

19.0' - 20.5'

(SSS)

{3.5' - 6.5'}: (Embankment Fill)

Loose to medium dense; very dark brown; silty fine SAND; moist to wet.

Groundwater at 8.9'

{6.5' - 7.5'}: (Buried Wetland)

Medium dense; black; silty, mucky fine SAND with organics; moist to very moist.

{7.5' - 8.2'}: (Buried Wetland)

Medium dense; gray; clayey fine

SAND; very moist to saturated.

S2-B @

2.0' - 3.5'

(SSS)

S2-C @

4.0' - 5.5'

(SSS)

S2-D @

7.0' - 8.5'

(SSS)

S2-E @

10.0' - 11.5'

(SSS)

S2-F @

12.0' - 13.5'

(SSS)

S2-G @

14.0' - 15.5'

(SSS)

S2-H @

17.0' - 18.5'

(SSS)

22.7%

26.1%

29.8%

{8.2' - 20.5'}: (Alluvium)

Medium dense; tan to brown;

SAND with seams of brown to dark brown silty fine SAND or fine sandy SILT; very moist to saturated.

Heaving sand at 14.0'

26.4%

28.0%

APPENDIX B

LLaabboorraattoorryy TTeessttiinngg

MOISTURE CONTENT DETERMINATION (ASTM D-2216)

Project: FWS Red Rock Lakes NWR Bridge

Project Number: 16-048

Sample Identification: BH-1 and BH-2

Soil Classification: Varies

Date Sampled: 5/3/16

Date Tested: 5/9/16

Tested By: EGS

Sample Identification: S1-A S1-B S1-C S1-D S1-E S1-F S1-G S1-H S1-I

Exploration Location: BH-1 BH-1 BH-1 BH-1 BH-1 BH-1 BH-1 BH-1 BH-1

Sample Depth (ft): 0.0-1.5 2.0-3.0 4.0-5.5 7.0-8.5 10.0-11.5 12.0-13.5 14.0-15.5 17.0-18.5 19.0-20.5

Container Number: O M W AA GG R Z Y CC

Weight of Container: 48.96 50.62 50.58 48.98 48.30 51.86 49.59 50.95 49.88

Container + Wet Soil: 165.76 209.00 181.08 227.16 299.37 301.61 306.68 221.52 334.77

Container + Dry Soil: 157.69 192.99 163.81 192.19 240.28 253.03 261.54 190.42 284.75

Weight of Water: 8.07 16.01 17.27 34.97 59.09 48.58 45.14 31.10 50.02

Weight of Dry Soil: 108.73 142.37 113.23 143.21 191.98 201.17 211.95 139.47 234.87

Moisture Content: 7.4% 11.2% 15.3% 24.4% 30.8% 24.1% 21.3% 22.3% 21.3%

Sample Identification: S2-A S2-B S2-D S2-E S2-F S2-G S2-H S2-I

Exploration Location: BH-2 BH-2 BH-2 BH-2 BH-2 BH-2 BH-2 BH-2

Sample Depth (ft): 0.0-1.5 2.0-3.0 7.0-8.5 10.0-11.5 12.0-13.5 14.0-15.5 17.0-18.5 19.0-20.5

Container Number: BB DD Q N T EE U HH

Weight of Container: 48.54 48.58 50.99 50.69 51.99 49.12 51.15 48.43

Container + Wet Soil: 221.33 227.42 259.58 215.97 264.40 196.93 279.06 196.77

Container + Dry Soil: 205.05 194.29 216.36 178.05 221.61 166.09 229.26 159.60

Weight of Water: 16.28 33.13 43.22 37.92 42.79 30.84 49.80 37.17

Weight of Dry Soil: 156.51 145.71 165.37 127.36 169.62 116.97 178.11 111.17

Moisture Content: 10.4% 22.7% 26.1% 29.8% 25.2% 26.4% 28.0% 33.4%

Reviewed By:

32 Discovery Drive Bozeman, MT 59718

Phone (406) 582-0221 Fax (406) 582-5770

Moisture Content Determinations

Craig R. Madson

GRAIN SIZE DISTRIBUTION (ASTM D-422)

Project Number: 16-048

Sample Identification: BH-2 at 7.0'

Soil Classification: sandy SILT

Date Sampled: 5/3/16

Date Tested: 5/9/16

Tested By: EGS

Natural Moisture Content: 0.0%

Gravel Portion (retained on #4 sieve): 1.0%

Sand Portion (passing # 4 & retained on #200 sieve): 47.6% Fines Portion (passing #200 sieve): 51.3%

Sieve Percent

Size Passing

4" 100.0%

3" 100.0%

2" 100.0%

1.5" 100.0%

1" 100.0%

3/4" 100.0%

3/8" 99.9%

#4 99.0%

#10 97.9%

#20 97.2%

#40 96.6%

#60 94.0%

#100 68.3%

#140 55.7% #200 51.3%

Reviewed By: ___________

Summary of Lab Test Data

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0.010.1110100

P e rc e n t P a s s in g

GRAIN SIZE DISTRIBUTION

Grain Size (mm)

23 1" 1/2" #4 #1 #20 #40 #100 #200

Gravels Fines

#60

Sands

4"

32 Discovery Drive

Bozeman, MT 59718 Phone (406) 582-0221

Fax (406) 582-5770

ATTERBERG LIMITS DETERMINATION (ASTM D-4318)

Project Number: 16-048

Sample Identification: BH-2

Soil Classification: sandy SILT

Date Sampled: 5/3/16

Date Tested: 5/11/16

Tested By: EGS

Test Results

Plastic Limit: 30.3

Liquid Limit: 42.2

Plasticity Index: 11.9

Reviewed By:_________________

0 10 20 30 40 50 60 70 80 90 100

P la s ti c it y I n d e x

Liquid Limit

PLASTICITY CHART

A-Line

CL- ML

ML

CL

ML or OL

MH or OH

CH

32 Discovery Drive Bozeman, MT 59718

Phone (406) 582-0221

APPENDIX C

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APPENDIX D

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Photograph 1: Downstream view of Elk Springs Creek at proposed bridge location.

Photograph 2: View of existing fill and location for proposed foundation.

Photograph 3: Upstream view of Elk Springs Creek at proposed bridge location.

Photograph 4: View of Elk Springs Creek crossing at proposed bridge location.

Photograph 5: View looking to the southeast at proposed bridge location along Culver Road.

APPENDIX E

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LIMITATIONS OF YOUR GEOTECHNICAL REPORT

GEOTECHNICAL REPORTS ARE PROJECT AND CLIENT SPECIFIC

Geotechnical investigations, analyses, and recommendations are project and client specific. Each project and each client have individual criterion for risk, purpose, and cost of evaluation that are considered in the development of scope of geotechnical investigations, analyses and recommendations. For example, slight changes to building types or use may alter the applicability of a particular foundation type, as can a particular client’s aversion or acceptance of risk. Also, additional risk is often created by scope-of-service limitations imposed by the client and a report prepared for a particular client (say a construction contractor) may not be applicable or adequate for another client (say an architect, owner, or developer for example), and vice-versa. No one should apply a geotechnical report for any purpose other than that originally contemplated without first conferring with the consulting geotechnical engineer. Geotechnical reports should be made available to contractors and professionals for information on factual data only and not as a warranty of subsurface conditions, such as those interpreted in the exploration logs and discussed in the report.

GEOTECHNICAL CONDITIONS CAN CHANGE

Geotechnical conditions may be affected as a result of natural processes or human activity. Geotechnical reports are based on conditions that existed at the time of subsurface exploration. Construction operations such as cuts, fills, or drains in the vicinity of the site and natural events such as floods, earthquakes, or groundwater fluctuations may affect subsurface conditions and, thus, the continuing adequacy of a geotechnical report.

GEOTECHNICAL ENGINEERING IS NOT AN EXACT SCIENCE

The site exploration and sampling process interprets subsurface conditions using drill action, soil sampling, resistance to excavation, and other subjective observations at discrete points on the surface and in the subsurface. The data is then interpreted by the engineer, who applies professional judgment to render an opinion about over-all subsurface conditions. Actual conditions in areas not sampled or observed may differ from those predicted in your report. Retaining your consultant to advise you during the design process, review plans and specifications, and then to observe subsurface construction operations can minimize the risks associated with the uncertainties associated with such interpretations.

The conclusions described in your geotechnical report are preliminary because they must be based on the assumption that conditions revealed through selective exploration and sampling are indicative of actual

Allied Engineering Services, Inc. Page 2 conditions throughout a site. A more complete view of subsurface conditions is often revealed during earthwork; therefore, you should retain your consultant to observe earthwork to confirm conditions and/or to provide revised recommendations if necessary. Allied Engineering cannot assume responsibility or liability for the adequacy of the report’s recommendations if another party is retained to observe construction.

EXPLORATIONS LOGS SHOULD NOT BE SEPARATED FROM THE REPORT

Final explorations logs developed by the consultant are based upon interpretation of field logs (assembled by site personnel), field test results, and laboratory and/or office evaluation of field samples and data.

Only final exploration logs and data are customarily included in geotechnical reports. These final logs should not be redrawn for inclusion in Architectural or other design drawings, because drafters may commit errors or omissions in the transfer process.

To reduce the likelihood of exploration log misinterpretation, contractors should be given ready access to the complete geotechnical report and should be advised of its limitations and purpose. While a contractor may gain important knowledge from a report prepared for another party, the contractor should discuss the report with Allied Engineering and perform the additional or alternative work believed necessary to obtain the data specifically appropriate for construction cost estimating purposes.

OWNERSHIP OF RISK AND STANDARD OF CARE

Because geotechnical engineering is much less exact than other design disciplines, there is more risk associated with geotechnical parameters than with most other design issues. Given the hidden and variable character of natural soils and geologic hazards, this risk is impossible to eliminate with any amount of study and exploration. Appropriate geotechnical exploration, analysis, and recommendations can identify and lesson these risks. However, assuming an appropriate geotechnical evaluation, the remaining risk of unknown soil conditions and other geo-hazards typically belongs to the owner of a project unless specifically transferred to another party such as a contractor, insurance company, or engineer. The geotechnical engineer’s duty is to provide professional services in accordance with their stated scope and consistent with the standard of practice at the present time and in the subject geographic area. It is not to provide insurance against geo-hazards or unanticipated soil conditions.

The conclusions and recommendations expressed in this report are opinions based our professional judgment and the project parameters as relayed by the client. The conclusions and recommendations assume that site conditions are not substantially different than those exposed by the explorations. If during construction, subsurface conditions different from those encountered in the explorations are observed or appear to be present, Allied Engineering should be advised at once such that we may review those conditions and reconsider our recommendations where necessary.

RETENTION OF SOIL SAMPLES

Allied Engineering will typically retain soil samples for one month after issuing the geotechnical report.

If you would like to hold the samples for a longer period of time, you should make specific arrangements to have the samples held longer or arrange to take charge of the samples yourself.

E. Environmental Litigation: Time lost due to work stoppage because of failure of the Contractor to comply with these requirements may not be the subject of a claim for extension of time, for additional costs, or damages.