GM_05-17_Mt_Baker_NF_ERFO_Drilling_Plan.pdf

Memorandum

Western Federal Lands Highway Division 610 E. Fifth Street

Vancouver, WA 98661-3801

Subject: GEOTECHNICAL INFORMATION: Date: March 22, 2017

Subsurface Investigation Plans for the

Darrington District Emergency Repairs, Mount Baker Emergency Repairs, & Skykomish Emergency Repairs Projects

From: Robert Kraig, Geotechnical Engineer Reply to: HFL-17, Geotechnical Services GM 05-17

To: Betty Chon, Project Manager; Mount Baker Emergency Repairs

WA ERFO 2016(1)-20(1)

Project Manager; Darrington District Emergency Repairs, PH-I

WA FS ERFO 2016(1)-20(3)

Matt Miller

Project Manager; Skykomish Emergency Repairs 2016

WA FS ERFO 2016(1)-20(2)

Introduction

The purpose of this memorandum is to provide the Subsurface Investigation Plan for the Mt. Baker

Emergency Repairs, Darrington District Emergency Repairs, and the Skykomish Emergency Repairs

2016 projects for the Mt. Baker Snoqualmie National Forest, WA (the Forest). The projects have

WFLHD Project Numbers WA FS ERFO 2016(1)-20(1), WA FS ERFO 2016(1)-20(3), and WA FS

ERFO 2016(1)-20(2), respectively. See Figure 1 for a Google Earth image showing the rough limits of the project locations of the individual project sites described below.

The Mt. Baker Emergency Repairs project consists of three locations located in Whatcom County along

Forest Roads (FR) 3100, 3140, and 1130/1144 at mileposts (MP) 6.7, 0.5, and 4.1/0.1. The sites are designated as 3100 MP 6.7, 3140 MP 0.5, and 1130 MP 4.1/1144 MP 0.1. These sites are shown in

Figure 2 and contained in Table 1, which lists the project site locations, designations, and approximate driving distance from the nearest referenced town.

The Darrington District Emergency Repairs project contains two sites that are located along FR 2700 and FR 2800, at MP 6.9 and MP 5.3, respectively. The sites are designated as 2700 MP 6.9 and 2800

MP 5.3. The 2700 MP 6.9 site is located in Darrington County and the 2800 MP 5.3 site is located in

Skagit County. These sites are shown in Figure 2 and also contained in Table 1.

Figure 1: Projects location limits (approx.) relative to Seattle, WA

Figure 2: Locations of the Mt. Baker Emergency Repairs & the Darrington District

Emergency Repairs, PH-I projects

Seattle

Victoria

Portland

Spokane

Washington

Projects Location Boundary (approx.)

Whatcom County

Snohomish County

Skagit County

The Skykomish Emergency Repairs 2016 project contains four sites in King County along FRs 6500, 6066, 5700, and 5200 at MP 0.15, MP 5.59, MP 23.034, and MP 6.1, respectively. These sites are designated as 6500 MP 0.15, 6066 MP 5.59, 5700 MP 23.034, and 5200 MP 6.1. This project also contains a site on FR 6300 at MP 17.2 that is located in Snohomish County, and designated as 6300 MP

17.2. See Figure 3 for the locations of the Skykomish Emergency Repairs 2016 project site locations.

For convenience, the project site locations, designations, and approximate driving distance from the nearest referenced town are provided in Table 1.

Figure 3: Locations of the Skykomish Emergency Repairs 2016

Table 1: Site Location Details Project National

Forest

Road

Milepost

(MP)

1.

Site

Designation

Driving

Distance, mi. /

Referenced

Town

Coordinates (from DSRs) 1., 2.

M

t. B ak er

E m erg en cy

R ep airs

3100 6.7 3100 MP 6.7 46 / Bellingham N 48.942513, W -121.941242

3140 0.5 3140 MP 0.5 50 / Bellingham N 48°56'55.07", W -121°56'24.88"

1130 &

4.1 &

0.1

1130 MP 4.1 &

1144 MP 0.1

65 / Bellingham N 48.76445, W -121.67248

D arrin g to n

D istrict

E m erg airs, P h ase I

2700 6.9 2700 MP 6.9 65 / Everett N 48°11'55.01", W -121°22'39.68"

2800 5.3 2800 MP 5.3 10 / Darrington N 48.3512, W -121.62463

Snohomish County

King County

Table 1: Site Location Details (cont.)

Project National

Forest

Road

Milepost

(MP)

1.

Site

Designation

Driving

Distance, mi. /

Referenced

Town

Coordinates (from DSRs) 1., 2.

S k y k o m ish

E erg airs

6500 0.15 6500 MP 0.15 51 / Everett N 47°43'1.11", W -121°20'34.43”

6066 5.59 6066 MP 5.59 59 / Everett N 47.724950, W -121.282599

5700 23.034 5700 MP 23.034 41 / Redmond N 47°39'10.03”, W -121°34'8.26”

5200 6.1 5200 MP 6.1 66 / Federal Way N 47.193566, W -121.403258

6300 17.2 6300 MP 17.2 67 / Everett N 47.913033, W -121.313317

1. Coordinates considered approximate.

2. Coordinates for the 2700 MP 6.9 site inferred from information provided by the DSR and review of

Google Earth imagery.

Anticipated repairs to the sites described above will include construction of Reinforced Soils Slopes

(RSSs), Special Rock Embankments, or Mechanically Stabilized Earth (MSE) walls, depending on the particular site conditions and/or limitations relative to a site. Other repair types may be recommended following the results of the subsurface investigations.

Damage site reports (DSRs) have been prepared for the projects sites described above. The DSRs are provided as an attachment to this memorandum.

Drilling Overview

Up to seven test holes may be drilled for the Mt. Baker Emergency Repairs project with designations of

B17-01 through B17-07. Up to three test holes could be drilled for the Darrington District Emergency

Repairs, PH-I project with designations of B17-08 through B17-10, and up to seven test holes might be drilled for the Skykomish Emergency Repairs 2016 project with designations of B17-11 through

B17-17. Planned test hole locations are discussed in the following sections. All test holes will be drilled within the disturbed road or shoulder areas. At the time of memorandum release, with the exception of the 6500 MP 0.15 site, it appears that all test hole drilling locations are located within

Forest boundaries. The 6500 MP 0.15 site appears to be located slightly outside of the Forest Boundary near Sykomish.

Test holes may reach depths of 75 feet below ground surface (BGS), or terminated 5 to 20 feet into competent bedrock, if encountered first. Test holes located within the existing roadway will be advanced through the existing driving surface, embankment fill, and into the native in-situ materials.

A track mounted drill rig or a truck mounted drill rig will advance the test hole borings. If a track mounted drill rig is used, measures will be taken to protect the driving surfaces. Maximum 8-inch outer diameter (OD) hollow stem auger system or a 4.6-inch O.D. HW casing advancer system will be used to advance the test holes through soil and rocky materials, respectively. HQ3 (3.8-inch O.D.) or NQ3

(3.0-inch O.D.) wireline coring systems will be used when rock is encountered. Soil and rock samples will be taken, when possible, at regular depth intervals. Soil samples will be taken using 3-inch

(maximum) OD split spoon samplers. Water will be required if rock is encountered and wireline coring systems are used. Drilling fluids will be prevented from entering creeks and streams using containment systems. Shelby tube samples may be taken if cohesive soils are encountered. The test hole will be backfilled in accordance with State regulations and patched using a cold-mix asphalt patch when drilled through pavement.

We do not anticipate that trees and/or shrubs will need to be removed for the drilling operations. We do not anticipate any off-road work. We did not observe overhead utilities during the site visit;

however, we anticipate that a utility locate will be required. At the time of memorandum release, it is not clear as to whether all of the sites are currently closed, or will be closed to the public during drilling operations; therefore, it is not known which sites, if any, that traffic control will be needed.

We anticipate that drilling would occur in the late spring or early summer of 2017. We understand that the date might be affected by the environmental approval process, contractor availability, and the duration of the contracting acquisition process. Factors such as the Contractor’s consecutive working days, or the length of daylight hours and time required to mobe to and from and (or) between the sites might affect the duration of the overall drilling operation. Excluding unforeseen circumstances, we estimate that a total of 13 to 14 days will be required for the onsite drilling work. However, the drilling operation may require a few additional days if difficult subsurface conditions are encountered, equipment breakdowns happen, or other unexpected events should occur.

Table 2 contains information regarding the possible test hole borings. Location information and test hole locations are discussed in the following sections.

Table 2: Test Hole Details

Project Designation

(NF Road & MP)

Test Hole

Designation

Estimated.

Depth (max), ft

Estimated Drilling

Duration, days

M

t. B ak er

E m erg airs

3100 MP 6.7 B17-01

B17-02

B17-03

3140 MP 0.5 B17-04

B17-05

1130 MP 4.1 &

1144 MP 0.1

B17-06

B17-07

1.25

D arrin g to n D istrict

E m erg en cy R ep airs, P H

-I

2700 MP 6.9 B17-08

B17-09

2800 MP 5.3 B17-10 40 1

S k y k o ish

E erg airs 2

6500 MP 0.15 B17-11 35 0.75

6066 MP 5.59 B17-12 45 0.75

5700 MP 23.034 B17-13

B17-14

0.75

5200 MP 6.1 B17-15

B17-16

6300 MP 17.2 B17-17 25 0.75

Drill Sites (Mt. Baker Emergency Repairs Project)

3100 MP 6.7

National Forest Road 3100 at MP 3.7. Number of holes = 3. Depth = 45’ for all test holes.

Figure 4: Location 3100 MP 6.7 Vicinity Map

Figure 5: Location 3100 MP 6.7 Site Plan

Site

B17-01 B17-02

B17-03 v v v v

3140 MP 0.5

National Forest Road 3140 at MP 0.5. Number of test holes = 2. Depth = 75’ for both test holes.

Figure 6: Location 3140 MP 0.5 Vicinity Map

Figure 7: Location 3140 MP 0.5 Site Plan

B17-04

B17-05

1130 MP 4.1 & 1144 MP 0.1

National Forest Road 1130 at MP 4.1 and National Forest Road 1144 at MP 0.1. Number of test holes = 2. Depth = 65’ for the 1130 MP 4.1 test hole (B17-06) & 35’ for the 1144 MP 0.1 test hole

(B17-07).

Figure 8: Location 1130 MP 4.1 & 1144 MP 0.1 Vicinity Map

Figure 9: Location 1130 MP 4.1 & 1144 MP 0.1 Site Plan

B17-06

B17-07 v

FR 1144

FR 1130

Drill Sites (Darrington District Emergency Repairs Project)

2700 MP 6.9

National Forest Road 2700 at MP 6.9. Number of test holes = 2. Depth = 55’ for both test holes.

Figure 10: Location 2700 MP 6.9 Vicinity Map

Figure 11: Location 2700 MP 6.9 Site Plan

B17-08 B17-09

2800 MP 5.3

National Forest Road 2800 at MP 5.3. Number of test holes = 1. Depth = 40’.

Figure 12: Location 2800 MP 5.3 Vicinity Map

Figure 13: Location 2800 MP 5.3 Site Plan

B17-10

Drill Sites (Skykomish Emergency Repairs 2016 Project)

6500 MP 0.15

National Forest Road 6500 at MP 0.15. Number of test holes = 1. Depth = 35’.

Figure 14: Location 6500 MP 0.15 Vicinity Map

Figure 15: Site view of Location 6500 MP 0.15

B17-11 v

6066 MP 5.59

National Forest Road 6066 at MP 5.59. Number of test holes = 1. Depth = 45’.

Figure 16: Location 6066 MP 5.59 Vicinity Map

Figure 17: Location 6066 MP 5.59 Site Plan (from DSR)

B17-12

5700 MP 23.034

National Forest Road 5700 at MP 23.034. Number of test holes = 2. Depth = 20’ for both test holes.

Figure 18: Location 5700 MP 23.034 Vicinity Map

Figure 19: Site View of Location 5700 MP 23.034

B17-13

B17-14

5200 MP 6.1

National Forest Road 5200 at MP 6.1. Number of test holes = 2. Depth = 30’ for both test holes.

Figure 20: Location 5200 MP 6.1 Vicinity Map

Figure 21: Site View of Location 5200 MP 6.1

B17-15

B17-16

6300 MP 17.2

National Forest Road 6300 at MP 17.2. Number of holes = 1. Depth = 25’.

Figure 22: Location 6300 MP 17.2 Vicinity Map

Figure 23: Site View of Location 6300 MP 17.2

B17-17