lake whatcom tunnel condition assessment report

Lake Whatcom Tunnel

Condition Assessment Report

DRAFT July 2015

Prepared for:

Prepared by

1100 ‐ 112th Avenue NE, Suite 500

Bellevue, WA, 98004‐4504

LAKE WHATCOM TUNNEL CONDITION ASSESSMENT REPORT

Contents 1. Introduction ................................................................................................................................ 1

2. Description of Tunnel ................................................................................................................... 1

3. Summary of Prior Inspections ....................................................................................................... 3

4. Field Inspection Methods and Approach ....................................................................................... 4 4.1 Defect Coding, Scoring, and Rehabilitation Priority .................................................................. 4 4.2 Inspection Plan and Safety ......................................................................................................... 4 4.3 Tunnel Stationing ....................................................................................................................... 5

5. Inspection Results ........................................................................................................................ 5

6. Summary of Key Results ............................................................................................................... 7

7. Recommendations ....................................................................................................................... 9 7.1 Regular Tunnel Monitoring and Maintenance ........................................................................... 9 7.2 Investigate and Repair Structural Defects ................................................................................. 9 7.3 Develop Secondary Supply ...................................................................................................... 10

Appendices A Lake Whatcom Tunnel Drawings B Summaries of Prior Condition Assessments C Defect Coding, Scoring, and Rehabilitation Priority D Inspection Plan E Lake Whatcom Tunnel Defect Distribution F Summary of Locations of Holes and Voids Contributing to High Priority Rating G Tunnel Inspection Reports

Tables

1 Lake Whatcom Tunnel Design Summary ................................................................................................ 2 2 Tunnel Liner Rating, Rehabilitation Priority, and Defects Per 100 foot Tunnel Segment ...................... 6

Figure

1 Alignment of Lake Whatcom Tunnel ...................................................................................................... 2

Exhibits

1 Screen House (Downstream End of Tunnel) ........................................................................................... 3 2 Gate House (Upstream End of Tunnel) ................................................................................................... 3 3 Permanent Station Markers .................................................................................................................... 5 4 Offset Longitudinal Fracture in Tunnel Liner .......................................................................................... 8 5 Typical Holes Found in the Tunnel Liner ................................................................................................. 8 6 Deteriorated Concrete Tunnel Liner ....................................................................................................... 9

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1. Introduction The City of Bellingham has been underway with assessing the condition of its water supply facilities that include its wood stave intake pipe, the Gate House just upstream of the tunnel, the Screen House just downstream of the tunnel, and the concrete cylinder supply pipelines downstream of the Screen House. The tunnel extends on its upstream end from the Gate House on the shore of Lake Whatcom to the Screen House on the downstream end where traveling screens remove fish and debris from the flow stream.

This condition assessment report documents activities from the inspection and evaluation of the Lake Whatcom Tunnel, performed in April 2015. The City of Bellingham (City) completed assessments of the tunnel on three previous occasions starting with the first inspection in 1988, then again in 1990, and finally a two-phased approach in 2012 and 2014. A summary and assessment of the 1988, 1990, and 2012 efforts are documented in a technical memorandum completed by CH2M HILL titled, City of Bellingham Lake Whatcom Tunnel: Preliminary Condition Assessment and Improvement Report (Task 2.2.2), November 7, 2014.

The 2014 tech memo focused primarily review of the data produced as part of the remote inspection (laser scanning and video) completed in 2012. That review guided the recent manned inspection work completed in April 2015. The manned inspection in April 2015 and the associated condition assessment presented herein are intended to begin a program of more-frequent, regular such efforts to extend the useful life of the tunnel for as long as practical.

2. Description of Tunnel The Lake Whatcom Water Supply Tunnel is located in Bellingham Washington, extending from Lake Whatcom to the City’s Screen House, as shown in Figure 1. It is a horseshoe-shaped tunnel constructed in 1939 with a length of 7,560 linear feet (LF) and a diameter of 6.5 ft. It has a capacity of approximately 100 million gallons per day (mgd). It appears the tunnel was constructed using drill and blast methods. It is fitted with a cast-in-place concrete lining. The tunnel conveys raw water from the upstream Gate House on the west shore of Lake Whatcom to the downstream Screen House in Whatcom Falls Park. A summary of the tunnel design is presented in Table 1.

Up until the closure of the Georgia Pacific Pulp and Paper Mill, which occurred over time between 2001 and 2007, the Lake Whatcom tunnel conveyed in excess of 50 mgd at times and regularly conveyed over 30 mgd for decades. Currently, flow through the tunnel is primarily to serve the City’s municipal needs, which range from peak daily usage of 20 mgd to an average daily usage of 10 mgd. Other average daily water usage through the tunnel includes approximately 1 mgd associated with the downstream Puget Sound Energy Encogen power generating facility and leakage. The leakage is the result of drainage valve in the Screen House stuck in the open position. It is unclear what the leakage rate is, but is believe to be approximately 5 mgd. The resulting current average flow through the tunnel is approximately 16 mgd, which equates to a tunnel velocity of approximately 1 foot per second.

Two photographs each of the Gate House and Screen House are presented as Exhibits 1 and 2, respectively. Drawings from the original design and construction of the tunnel are presented in Appendix A. These drawings include a plan and profile, typical sections, tunnel details, shaft structure design details, geologic information, and progress chart from the original tunnel construction showing the geology encountered along the alignment.

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FIGURE 1 Alignment of Lake Whatcom Tunnel

TABLE 1 Lake Whatcom Tunnel Design Summary

Parameter Description

Designer Baar and Cunningham

Contractor B.H Sheldon (Tunnel Contractor)

Construction Completed 1939

Tunnel length 7,560 feet (1.4 miles)

Upstream Elevation 298.5 feet

Downstream Elevation 290.94 feet

Tunnel slope 0.1%

Cross section per plan Horseshoe; 5.0 feet bottom width × 6.25 feet high

Cross section (lined) as observed Horseshoe; 6.3 feet Spring line width × 6.5 feet high

Intermediate Shaft Gate House

Screen House Lake Whatcom

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EXHIBIT 1

Screen House (Downstream End of Tunnel)

EXHIBIT 2 Gate House (Upstream End of Tunnel)

3. Summary of Prior Inspections The tunnel was formally inspected on three separate occasions starting with the first inspection in April 1988 by Hart Crowser and then again in 1990 by Hart Crowser. A third inspection was completed in 2012 by iPi using a remotely operated vehicle (ROV). A review of these inspections was completed by CH2M HILL in 2014. These reports are listed below and described in the following subsections:

• 1988 Tunnel Liner Observation and Preliminary Geotechnical Engineering Assessment, Hart Crowser

• 1990 Geotechnical Engineering Assessment, Tunnel Observations, Repairs, Tests and Exploratory Work, Hart Crowser

• 2012 ROV Inspection Report, iPi: Laser scanning data (discussed further below); ROV camera inspection video; Support diver helmet camera video

• 2014 City of Bellingham Lake Whatcom Tunnel: Preliminary Condition Assessment and Improvement Report (Task 2.2.2), November 7, 2014, CH2M HILL

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Review of the reports summarizing the prior inspection and condition assessment efforts aided the work planning for the April 2015 tunnel inspection. Brief summaries of these prior inspections are presented in Appendix B.

4. Field Inspection Methods and Approach The inspection of the Lake Whatcom Tunnel liner was completed on April 22, 2015 in conformance with industry accepted practices and standards. The inspection approach implemented was based on practices and standards defined by the National Association of Sewer Service Companies (NASSCO) Pipe Assessment Condition Program (PACP) for small diameter pipelines. These practices and standards were modified for the Lake Whatcom tunnel inspection, as there is no similar defined condition assessment standards for large diameter tunnels in the United States

4.1 Defect Coding, Scoring, and Rehabilitation Priority Defect terminology, associated defect codes, and concrete liner rating used during the field inspection is presented Appendix C. Also presented Appendix C, are associated rehabilitation priorities associated with the defect scoring. An understanding of the defect coding, liner rating values, and rehabilitation priority presented in Appendix C is necessary to understand the inspection results presented in Section 5.

The standard inspection defect coding used for this project is grouped into three main categories: structural, operational, and other. In general, severe defects warrant rehabilitation. Most severe defects are of a structural nature.

Structural defects consist of the fractures, cracks, collapse, breaks, and surface damage. Definitions of the structural codes used for this inspection are presented in Appendix C. Operational defects include debris, deposits, protruding structures, and infiltration. Definitions of the operational codes used for this inspection are presented in Appendix C. Other “defects” are in some cases minor defects and in other cases simply observations of conditions within the tunnel related to operations or other activities.

Each 100-foot length of the concrete liner of the tunnel (from station to station) was rated or “scored” with respect to defects in conformance with the rating methodology presented in Appendix C. The priority for rehabilitation of each of the 100-foot lengths was then developed based on the NASSCO standardized approach.

4.2 Inspection Plan and Safety The Inspection Plan for Lake Whatcom Tunnel, dated March 5, 2015 included in Appendix D was prepared to guide the tunnel inspection, which was completed over the course of a single day between the hours of 8am and 6pm.

The tunnel was entered under confined space entry safety procedures in conformance with a tunnel entry safety plan that was developed under separate cover. Life Rescue, Inc provided safety support for the tunnel entrants based on the safety plan. Pre-entry safety coordination meetings were conducted several weeks prior to the tunnel entry, the day before the tunnel entry, and the morning prior to the tunnel entry. Confined space entry attendants (two each; 6 total plus one supervisor) were stationed the upstream, intermediate, and downstream tunnel access points, and the inspection team was equipped with air monitors. CH2M’s safety manager was present on site throughout the day to serve as the overall safety lead for the tunnel entry.

Air flow through the tunnel was enhanced using a 10,000 cfm blower at the Gate House opening. The blower system appeared to provide more than adequate ventilation. As the inspection team neared the Gate House, as they completed the inspection, the blower was turned off. Even after the blower was turned

4 WT0622151047SEA


off there was noticeable air flow through the tunnel. Even during this time air quality was measured continually. Oxygen levels remained above 20.5 percent; there was no detection of carbon monoxide; no detection of hydrogen sulfide; no detection of methane.

4.3 Tunnel Stationing Permanent markers were placed every 100 feet on the south side of the tunnel to aid location of inspection documentation and to aid future inspections. The permanent markers consist of an aluminum washer stamped with the year “2015” and the corresponding station number, as shown in Exhibit 3. Washers were affixed to stainless steel friction anchors that were pounded into holes drilled with a rotary hammer drill.

EXHIBIT 3 Permanent Station Markers

5. Inspection Results Key results of the April 2015 inspection of the concrete tunnel liner are presented in Table 2. The liner rating was computed and the rehabilitation priority developed on a per-100-foot section based on the methodology presented in Appendix B. The major defect types contributing to the “high” rehabilitation priority are presented in Table 2 given the need to address these portions of the tunnel soon. The “high” rehabilitation priority rows are highlighted. A graphical representation of the rehabilitation priority is presented in Appendix E. In addition to presenting distribution of rehabilitation priority along the tunnel, the figure in Appendix E presents the location of tunnel defects with a score or weighting of 4 (no tunnel defects with a score of 5 were observed).

As noted in Table 2, the vast majority of the major defects that impact rehabilitation priority are holes. Holes in the liner are of particular concern because they often indicate the presence of voids behind the liner as well as enable the migration of fines from behind the line, which enables growth in voids. As a result, the specific locations of hole defects observed during the inspection are presented in the table in Appendix F.

The specific defects contributing to the “low” and “medium” rehabilitation priority are not presented in Table 2, but instead can be reviewed in the tunnel inspection reports included in Appendix G. The tunnel inspection reports included in Appendix G present detailed descriptions of each of the tunnel liner defects, as observed in the field.

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TABLE 2 Tunnel Liner Rating, Rehabilitation Priority, and Defects Per 100 foot Tunnel Segment

Start Station End Stations Concrete Tunnel Liner Rating Rehabilitation Priority Major Defect Noted

0+00 1+00 2 Low Refer to Appendix G 1+00 2+00 2 Low Refer to Appendix G 2+00 3+00 3 Medium Refer to Appendix G 3+00 4+00 3 Medium Refer to Appendix G 4+00 5+00 0 Not required Refer to Appendix G 5+00 6+00 2 Low Refer to Appendix G 6+00 7+00 0 Not required Refer to Appendix G 7+00 8+00 3 Medium Refer to Appendix G 8+00 9+00 3 Medium Refer to Appendix G 9+00 10+00 3 Medium Refer to Appendix G

10+00 11+00 3 Medium Refer to Appendix G 11+00 12+00 3 Medium Refer to Appendix G 12+00 13+00 3 Medium Refer to Appendix G 13+00 14+00 0 Not required Refer to Appendix G 14+00 15+00 3 Medium Refer to Appendix G 15+00 16+00 3 Medium Refer to Appendix G 16+00 17+00 4 High Hole Soil Visible 17+00 18+00 4 High Hole Soil Visible 18+00 19+00 3 Medium Refer to Appendix G 19+00 20+00 3 Medium Refer to Appendix G 20+00 21+00 4 High Hole Soil Visible 21+00 22+00 4 High Hole Soil Visible 22+00 23+00 3 Medium Refer to Appendix G 23+00 24+00 4 High Hole Soil Visible 24+00 25+00 3 Medium Refer to Appendix G 25+00 26+00 3 Medium Refer to Appendix G 26+00 27+00 3 Medium Refer to Appendix G 27+00 28+00 4 High Hole Soil Visible 28+00 29+00 3 Medium Refer to Appendix G 29+00 30+00 3 Medium Refer to Appendix G 30+00 31+00 3 Medium Refer to Appendix G 31+00 32+00 3 Medium Refer to Appendix G 32+00 33+00 4 High Fracture Longitudinal, Offset 33+00 34+00 3 Medium Refer to Appendix G 34+00 35+00 4 High Hole Soil Visible 35+00 36+00 0 Not required Refer to Appendix G 36+00 37+00 3 Medium Refer to Appendix G 37+00 38+00 1 Not required Refer to Appendix G 38+00 39+00 4 High Hole Soil Visible 39+00 40+00 2 Low Refer to Appendix G 40+00 41+00 4 High Hole Soil Visible 41+00 42+00 0 Not required Refer to Appendix G 42+00 43+00 3 Medium Refer to Appendix G 43+00 44+00 3 Medium Refer to Appendix G 44+00 45+00 2 Low Refer to Appendix G 45+00 46+00 0 Not required Refer to Appendix G 46+00 47+00 4 High Hole Soil Visible 47+00 48+00 4 High Hole Soil Visible 48+00 49+00 3 Medium Refer to Appendix G

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TABLE 2 Tunnel Liner Rating, Rehabilitation Priority, and Defects Per 100 foot Tunnel Segment

Start Station End Stations Concrete Tunnel Liner Rating Rehabilitation Priority Major Defect Noted

49+00 50+00 4 High Hole Soil Visible 50+00 51+00 4 High Hole Soil Visible 51+00 52+00 3 Medium Refer to Appendix G 52+00 53+00 0 Not required Refer to Appendix G 53+00 54+00 0 Not required Refer to Appendix G 54+00 55+00 0 Not required Refer to Appendix G 55+00 56+00 0 Not required Refer to Appendix G 56+00 57+00 0 Not required Refer to Appendix G 57+00 58+00 4 High Hole Soil Visible 58+00 59+00 3 Medium Refer to Appendix G 59+00 60+00 4 High Hole Soil Visible 60+00 61+00 4 High Fracture Longitudinal, Offset 61+00 62+00 3 Medium Refer to Appendix G 62+00 63+00 4 High Hole Soil Visible 63+00 64+00 4 High Hole Soil Visible 64+00 65+00 4 High Hole Soil Visible 65+00 66+00 3 Medium Refer to Appendix G 66+00 67+00 2 Low Refer to Appendix G 67+00 68+00 4 High Hole Soil Visible 68+00 69+00 0 Not required Refer to Appendix G 69+00 70+00 0 Not required Refer to Appendix G 70+00 71+00 0 Not required Refer to Appendix G 71+00 72+00 4 High Hole Soil Visible 72+00 73+00 3 Medium Refer to Appendix G 73+00 74+00 2 Low Refer to Appendix G 74+00 75+00 0 Not required Refer to Appendix G 75+00 76+00 2 Low Refer to Appendix G

Note: 100-foot segments with a “High” priority rating are highlighted in blue.

6. Summary of Key Results In general, the Lake Whatcom tunnel liner is in good condition and appears to be stable. Seventy-one (71) percent of the tunnel has a rehabilitation priority of “Not Required” to “Medium” (liner rating levels of 0 to 3). These portions of the tunnel require further monitoring and repairs that should be implemented within 5 to 10 years. However, twenty nine (29) percent of the tunnel was assigned a rehabilitation priority of “High” (liner rating level of 4). These portions of the tunnel warrant repairs within the one year to prevent the damage associated with these defects from becoming worse. No sections of the tunnel were given a rehabilitation priority of “Immediate” (liner rating level of 5). As presented in the table in Appendix F, a total of 52 locations within the tunnel were identified as either a hole with a visible void (Hole Void Visible) or a hole with visible migration of soil (Hole Soil Visible). A particularly large void was discovered behind the liner at station 75+11 to 75+14. The void appeared to be approximately 3-feet in diameter and at least 7-inches deep, but have extended further. The liner was still intact over the void. The inspection identified 103 locations with longitudinal fracturing of the concrete tunnel liner. Five of these fractures had offsets of up to 0.19 inches. An example of one of these offset fractures is presented in Exhibit 4. Longitudinal fracturing that is offset can be a significant structural defect that could indicate

WT0622151047SEA 7


uneven bearing of the tunnel liner on the rock and soil behind the liner. The shale rock through which the tunnel is constructed could have potential for swelling and creating the conditions for fracture. The importance of these fractures is dependent on the extent to which there is change (if any) in their size and offset. There were several tunnel liner locations (5+47 to 5+49, 30+45, 33+01 to 33+02, and 33+06 to 33+07) where the liner was thin or deteriorating to a point where the concrete could easily be scraped away at the surface. One example of this deterioration is presented in Exhibit 6.

EXHIBIT 4 Offset Longitudinal Fracture in Tunnel Liner

EXHIBIT 5 Typical Holes Found in the Tunnel Liner

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EXHIBIT 6 Deteriorated Concrete Tunnel Liner

7. Recommendations As stated above, the Lake Whatcom tunnel is generally in good condition, able to continue providing beneficial service to the City, and worthy of capital expenditure to keep it in a useful condition into the future. Although the tunnel has provided relatively minimal to low cost service since 1940, rehabilitation of the tunnel is necessary and regular monitoring are essential to extend its useful life. Replacement of the tunnel would far exceed the cost of rehabilitation. Specific recommendations presented in the sections below relate to:

• Regular Tunnel Monitoring and Maintenance. This regular, programmatic approach will enhance the long-term viability of the tunnel.

• Investigate and Repair Structural Defects. This targeted effort is necessary to address specific structural defects that are a threat to the integrity of the concrete tunnel liner.

• Develop Secondary Supply. This capital improvement project will enable effective repair of defects in the tunnel but will also enable repair of critical pipeline damage at the Screen House.

7.1 Regular Tunnel Monitoring and Maintenance The City should implement a program over the long-term future to conduct manned-entry inspections of the tunnel at a minimum of every five years. These regular inspections should make use of the new, permanent station markers to enable re-examination of key areas with structural and operational defects. The regular tunnel monitoring program should track structural and operation defects and the effectiveness and condition of rehabilitation improvements. Maintenance and repair activities should be implemented on a regular basis in direct response to the findings of the monitoring program.

7.2 Investigate and Repair Structural Defects The structural defects (holes and fractures) observed in the liner represent the greatest threat to its integrity and continued use of the tunnel. These structural defects contributed to 29 percent of the liner receiving a “High” rehabilitation priority, meaning that these defects should be repaired within the next year.

The following actions are recommended within the next year:

• Large Void at 75+11 to 75+14. Investigate and repair the large void behind the liner at station 75+11 to 75+14. This void is large enough that it warrants removal of a portion of the liner over the void,

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evaluating the extent of the void, and identifying flow conditions. After this investigation, the void should be filled and the liner replaced to match existing.

• Longitudinal Fracturing with Offsets. Investigate longitudinal fractures, especially the fractures with offsets to determine the catalyst. Core samples of the liner and rock behind the line should be collected. The rock sample should be characterized and tested for swell potential. Consider using crack gauges at specific locations to track any changes over time to fracture offset.

• Repair of Holes. As noted above, there were 52 locations in the tunnel liner where holes were identified. These holes should be investigated and repaired. Left unrepaired, these holes will allow for the continued migration of fine grained material and the growth of voids behind the concrete tunnel liner. The result could be instability of the liner and potentially collapse.

7.3 Develop Secondary Supply To effectively implement rehabilitation of the tunnel liner to correct structural defects, it will be necessary for the tunnel to be taken out of service for an extended period of time. Currently, it’s not possible to have access to the tunnel for more than approximately 12 continuous hours at any given time. This is because the tunnel is the sole means of getting water from Lake Whatcom to the City’s Whatcom Falls Water Treatment Plant. Without being able to take the tunnel out of service for an extended period of time, investigating and repairing holes and voids would require many short shut downs of the tunnel, which would be costly and severely impact the City’s water system operations staffing.

Consequently, it is recommended the City expedite and accelerate its plans to develop the existing 100-year-old City-owned supply that is currently supplying the fish hatchery owned by the Washington State Department of Fish and Wildlife next to the Screen House. This secondary supply could be placed into temporary service over the course of several weeks or even months to enable critical rehabilitation to the City’s Screen House that has previously been identified, as well as enabling comprehensive examination and rehabilitation the tunnel.

Of the recommendations presented herein for monitoring, maintaining, and rehabilitation of the tunnel, development of the City’s old Lake Whatcom supply as a temporary supply alternative and as an emergency backup supply to the City’s current Lake Whatcom supply should be considered as its highest priority. This second supply must be developed and able to be placed into service before rehabilitation of the tunnel can be implemented effectively.

Further supporting the high priority of developing the old Lake Whatcom supply is the fact that the City’s 72-inch diameter wood stave intake pipeline is under a moderate risk of failure with the potential consequence of that failure being high. An emergency backup supply would help to mitigate this potential issue. Refer to the November 7, 2014 technical memorandum entitled City of Bellingham Wood-Stave Intake Pipeline: Condition Assessment (Task 2.1.5), documenting the condition assessment of the wood stave intake pipeline.

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Appendix A Lake Whatcom Tunnel Drawings

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3'~5''Laqqlng5paced4"apart oras dose asnecessary to holdmaterial.

4'~4"5trut5. To be removedbefore concre~ing

Lonairudinai BarsVi'~ 2'-0"%.

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qravei fi\led trend,.

6"to Ie" 5 ewer Pipeas required ingravel filled trench

SECTION 0Scale:·r· }:O"

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Skeleton 5ets may be used omiHing Lagging-

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Skeleton Sets may be used omitting Lagging

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WA1~R~ORKS IMPROVeMeNT

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LOCAT!ON MAP OF

LAKE WHATCOMI WATER TUNNEL

FROM WATKINS POINTTO WHATCOM FALLS PARK

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Appendix B Summaries of Prior Condition Assessments

Appendix B

Summary of Prior Condition Assessments

Brief summaries of the prior inspections and condition assessments from 1988, 1990, 2012, and 2014 are presented in the sections below. Other inspections and condition assessments of the tunnel may have been undertaken prior to those listed below. However, no documentation was available describing any such efforts.

B.1 Hart Crowser Manned Inspection – 1988 The tunnel was first inspected in 1988 by the consultant Hart Crowser. The report documenting this inspection was titled: “Tunnel Liner Observation and Preliminary Geotechnical Engineering Assessment Lake Whatcom Water Tunnel Watkins Point to Whatcom Falls Park Bellingham, Washington”, dated June 10, 1988. The consultant assembled two inspection teams for a manned entry tunnel inspection that included member from the City, Diversified Diving Services, and Hart Crowser. The two teams inspected separate sections of the tunnel given the time constraints. The inspection focused on collecting data associated with structural damage of the liner, assessing concrete strength, and documenting inflow.

Results of the inspection indicated that there were signs of distress in the tunnel liner, but that these signs did not pose a significant risk of immediate collapse of the tunnel under normal operating conditions. It was noted that the quality of the concrete was questionable and should be more thoroughly evaluated. Voids and major cracks were noted allowing seepage paths for the flow of water and were contributing to flow in the underdrains and likely flow outside the tunnel liner.

The consultant recommended that future investigation include taking a series of cores of the concrete liner for testing in the laboratory to determine the quality of the concrete. They proposed an investigation of the liner / rock interface through additional rock coring and borehole photography to determine the effectiveness of the liner and to determine if flow outside the liner was having an impact on the long term stability of the tunnel. It was suggested that repair options to the existing tunnel liner be evaluated to extend the life of the tunnel.

B.2 Hart Crowser Manned Inspection – 1990 Hart Crowser completed a supplemental investigation in April 1990. A report was prepared documenting this work, titled: “Geotechnical Engineering Assessment Tunnel Observation, Repair, Tests, and Exploratory Work Lake Whatcom Water Tunnel Bellingham, Washington”, dated September 21, 1990. The purpose of the inspection was to assess the condition of the existing liner and tunnel /liner interface as well as to perform trial repair methods so that they could assess the procedures and evaluate the performance during a subsequent tunnel shutdown.

The consultant assembled a team for the manned entry tunnel inspection that included members from the City’s Department of Public Works, National Concrete Cutting, Gelco, and Hart Crowser. The team inspected separate sections of the tunnel given the time constraints. The inspection focused on collecting data along the entire length of the tunnel using video, coring the liner in 2 separate locations for laboratory testing, contact grouting at predetermined locations, and patching of know defect to reduce seepage.

The report noted that the tunnel was generally in good condition; however there were about 10 locations where serious problems were evident. These problems included offset cracks and poor quality concrete, which indicate a high potential for future instability at these locations. Recommendations from the report

WT0622151047SEA B-1

APPENDIX B SUMMARY OF PRIOR CONDITION ASSESSMENTS

noted that more significant repairs at other locations could realistically be accomplished and that advance planning and timely progressive maintenance would be the best means for avoiding future lining failure.

B.3 Interactive Pipe Inspection (iPi) ROV Inspection – 2012 Interactive Pipe Inspection, Inc. (iPi) completed an unmanned inspection of the Lake Whatcom Water Supply Tunnel in 2012. A report was prepared to document this work, and it is titled: “Water Filtration Raw Water Tunnel Inspection”, dated December, 2012. iPi used a Robotic Crawler & High Definition CCTV unit, fitted with the Underwater Laser at the bottom of the submersed tunnel allowing for audio, video feed and recording. The laser scanning was performed as an alternative to dewatering and man-entry tunnel inspection. Although unable to provide a comprehensive visual inspection of the tunnel due to floating material in the tunnel which obscured the CCTV unit, the laser scanning could identify major defects and deformation in the tunnel by providing a cross-sectional profile measurement. Observations made during the inspection were reviewed and evaluated by CH2M HILL.

The laser scanning data from the 2012 ROV inspection included 3D point clouds collected approximately every 9 linear feet along the length of the tunnel. The laser scanning technology combines laser illumination (similar to LIDAR) with computer processing to provide empirical data of the tunnel inner wall surface. The laser itself is an independent tool that was attached to a treaded platform and the point clouds were post-processed after the inspection. The point clouds each include a scanned portion of the tunnel approximately 5 to 6 linear feet long. Unlike the previous inspection reports from 1988 and 1990, no detailed analysis of the scanning data was prepared.

B.4 CH2M HILL Preliminary Condition Assessment – 2014 In 2014 CH2M HILL completed a “preliminary” condition assessment of the Lake Whatcom tunnel by reviewing the data produced as part of the iPi ROV inspection in 2012. That assessment was “preliminary” to the manned-inspection that was planned for 2015. The intention was to review the iPi data to guide the scope of the 2015 inspection work. Additionally, given the lengthy time since the prior manned inspections of 1988 and 1990, those efforts and the results of those efforts were summarized.

The 2012 report included development of a series of three dimensional surface models from the laser scan data. From these models, the following could be observed:

• Cross-sectional deformation of the tunnel liner • Discrete areas of build-up or voids in the tunnel liner • Longitudinal deformation/shifting of the tunnel liner

The data only included scan sections 5 to 6 feet long, spaced every 9 feet on center. The result was a data gap of 3 to 4 feet between scans. Limitations to the laser scanning and associated modeling include the fact that the laser can only reflect off the nearest solid surface it encounters. As a result, cannot distinguish the type of material it scans. This means that it is not possible to definitively determine if the observed anomalies that are intruding into the liner are a result of ingressing soil/fines through cracks in the tunnel liner – or simply build-up or patching material on the tunnel liner wall. That stated, the anomalies observed provided excellent guidance on focus areas for the manned inspection that was completed in April 2015.

B-2 WT0622151047SEA

Appendix C Defect Coding, Scoring, and Rehabilitation Priority

Appendix C

Defect Coding, Scoring, and Rehabilitation Priority

Presented herein is a discussion of some of the key tunnel liner defect coding definitions relative to the defects encountered in the Lake Whatcom tunnel. Also included is a discussion of defect coding, an example calculation of how segments of the tunnel lining were rated, and a discussion of liner rehabilitation priority. At the end of this appendix is a table listing the defect codes and their relative scoring or weighting.

C.1 Tunnel Liner Defect Coding The NASSCO PACP method consists of structural and operational type defects that are weighted and then are scored. The types of defects used in this inspection are discussed below.

C.1.1 Structural Defect Coding Definitions There are two categories of defects: structural and operational. Structural defects generally result in rehabilitation of the liner result in maintenance of the liner. Key structural defects are defined below.

C.1.1.1 Fractures A fracture is a crack that is open more than 0.015 inch wide and is sometimes accompanied by deformation or evidence of infiltration. It is challenging to differentiate a crack on the interior of the liner from fractures when the fractures are closed. If inspection methods are used that are suited for only above the flow line, fractures below the flow line may not be detected unless the pipe is fully dewatered. There are several types of typical fractures. Fractures observed in the Lake Whatcom tunnel include: longitudinal, circumferential, and diagonal.

C.1.1.2 Cracks A crack is a defect in the liner that is closed at the surface. The distinction between cracks and fractures is necessary so that consecutive inspection data can be used to determine the progress of deterioration. There are several types of cracks that are typically observed. Fractures in the Lake Whatcom tunnel include: longitudinal, circumferential, and diagonal.

C.1.1.3 Hole The classification of a hole is used if the defect in the liner wall is less than 12 inches in diameter or if it is rectangular in shape less than 12-inch by 12-inches or equivalent area. A hole in a liner generally warrants repair, particularly if there is evidence of infiltration or migration of fines from behind the line.

C.1.1.4 Surface Damage Surface damage to a liner occurs on the inner portion of the liner and is caused by chemical attack, biological attack or wear. For a concrete tunnel liner, surface damage includes spalling of the material, and or exposure and corrosion of the reinforcement.

C.1.2 Operational Defect Coding Definitions Operational defects generally result in the maintenance of the liner. The primary operational defects identified as part of the investigation are defined below.

C.1.2.1 Debris Debris is a deposit of soils, rock, or other materials that may disrupt flow. If debris consists of construction-related materials, it may be an indication that a more severe condition may exist upstream. A reduction in tunnel or pipe diameter is used to determine severity. This was not an issue in the Lake Whatcom tunnel.

WT0622151047SEA C-1

APPENDIX C DISCUSSION OF TUNNEL LINER DEFECT CODING, DEFECT SCORING, LINER RATING, AND REHABILITATION PRIORITY

C.1.2.2 Infiltration Infiltration is the ingress of groundwater into a tunnel or pipe through a defect. Mineral deposits on the liner often indicate infiltration. Infiltration can disrupt the stability of the mass behind the liner.

C.2 Defect Scoring or “Weighting” NASSCO PACP identifies the scoring of the liner as a rating system and uses a numerical grading system to define the severity of each pipe defect. Defect severity grades for structural defects and operation and maintenance (O&M) defects are assigned by NASSCO PACP based on the risk of further deterioration or failure. The numerical scores or “weights” rank defects on a scale of 1 to 5, with 1 being best (least risk) and 5 being worst (highest risk). A table summary of these scores are presented at the end of this appendix.

C.3 Example Calculation for Liner Rating PACP uses several methods for scoring the condition of the liner: segment grade scoring, overall pipe rating, structural pipe rating, O&M pipe rating, structural pipe rating index, O&M pipe rating index, and overall pipe rating index. All methods offer their own unique approach for characterizing the condition of the liner. The overall pipe rating index was used for representing the condition of the Lake Whatcom tunnel liner on a per-100-foot segment basis.

The overall pipe rating index is an expression of the defect severity found in the pipe over a 100-foot segment of the tunnel. The index is calculated scoring each defect then adding up the total score. The total is then divided by the number of defects encountered in a defined 100-foot segment. As an example, a pipe segment from Stations 1+00 to 2+00 contains the following defects and associated scores:

1. 5 circumferential cracks = 5 (PACP assigns a score of 1 to each circumferential crack) 2. 2 circumferential fractures = 6 (PACP assigns a score of 3 to each circumferential fracture) 3. 3 longitudinal cracks = 6 (PACP assigns a score of 2 to each longitudinal crack) 4. The sum of defects between Stations 1+00 to 2+00 = 17, calculated by adding 5 + 6 + 6 5. The total number of defects in the 100 foot segment = 10, calculated by adding 5 + 2 + 3

Therefore, in this example the overall pipe rating index for the liner between Stations 1+00 and 2+00 is 2, which is calculated by dividing 17 by 10 and rounding up to 2.

C.4 Rehabilitation Priority The scores calculated for each 100-foot tunnel segment, as described in the example above, are a rehabilitation priority. NASSCO has established a priority for rehabilitation efforts based on calculated scoring for each segment of the liner. The rehabilitation ranges from “immediate” where the liner has failed, to “not required” where the tunnel is in good or excellent condition. Timelines associated with the rehabilitation priority range from immediate to more than 10 years, depending on the defect(s). Rehabilitation efforts may include everything from replacing the liner to simply monitoring observed defects over time. Rehabilitation priority and timing is presented in the below.

Rehabilitation Priority from NASSCO PACP

Condition Rating Implication Rehabilitation Priority Recommended Timing

5 Failed or failure imminent Immediate —

4 • Very poor condition • High structural risk

High 1 year

3 • Poor condition • Moderate structural risk

Medium 5 years

C-2 WT0622151047SEA

APPENDIX C DISCUSSION OF TUNNEL LINER DEFECT CODING, DEFECT SCORING, LINER RATING, AND REHABILITATION PRIORITY

Rehabilitation Priority from NASSCO PACP

Condition Rating Implication Rehabilitation Priority Recommended Timing

2 • Fair condition • Minimal structural risk

Low 5 to 10 years

1 or 0 Good or excellent condition not required >10 years

WT0622151047SEA C-3

Defect Group Name Defect Group Code Defect Weight Group

Access Point Blind Shaft ABS 1 Operational

Access Point Cleanout ACO 1 Operational

Access Point Discharge Point ADP 1 Operational

Access Point Drift Tunnel ADT 1 Operational

Access Point Junction Box AJB 1 Operational

Access Point Meter AM 1 Operational

Access Point Manhole AMH 1 Operational

Access Point Other Special Chamber AOC 1 Operational

Access Point Drill Hole ( < 3' ) APDH 1 Operational

Access Point Shaft Hole ( 3' or > ) APSH 1 Operational

Access Point Tee Connection ATC 1 Operational

Access Point WW Access Device AWA 1 Operational

Access Point Wet Well AWW 1 Operational

Pipe Failure Broken B 5 Structural

Brickwork Displaced BDB 5 Structural

Brickwork Dropped Invert BDI 5 Structural

Brickwork Missing BMB 4 Structural

Brickwork Missing Mortar BMM 3 Structural

Broken Soil Visible BSV 5 Structural

Broken Void Visible BVV 5 Structural

Crack C 1 Structural

Crack Angular CA 2 Structural

Crack Circumferential CC 1 Structural

Crack Longitudinal CL 2 Structural

Crack Multiple CM 3 Structural

Crack Spiral CS 2 Structural

Deposits Attached Encrustation DAE 1 Operational

Deposits Attached Grease DAGS 1 Operational

Deposits Attached Ragging DAR 1 Operational

Deposits Attached Other DAZ 1 Operational

Deformed Brick DB 5 Structural

Deposits Ingress Fines Silt/Sand DNF 1 Operational

Deposits Ingress Gravel DNGV 1 Operational

Deposits Ingress Other DNZ 1 Operational

Deformed Pipe DP 5 Structural

Deposits Settled Hard/Compacted DSC 1 Operational

Deposits Settled Fine DSF 1 Operational

Deposits Settled Gravel DSGV 1 Operational

Deposits Settled Other DSZ 1 Operational

Fracture F 3 Structural

Fracture Angular FA 3 Structural

Fracture Circumferential FC 3 Structural

Fracture Longitudinal FL 4 Structural

Fracture Multiple FM 4 Structural

Fracture Spiral FS 4 Structural

Geologic Feature GF 1 Other

Defect Code Summary Table


Pipe Failure Hole H 2 Structural

Hole Soil Visible HSV 4 Structural

Hole Void Visible HVV 4 Structural

Infiltration Dripper ID 1 Operational

Infiltration Gusher IG 1 Operational

Infiltration Runner IR 1 Operational

Intruding Seal Material Grout ISGT 1 Operational

Intruding Seal Material Sealing Ring ISSR 1 Operational

Intruding Seal Material Other ISZ 1 Operational

Infiltration Weeper IW 1 Operational

Joint Angular JA 2 Structural

Joint Offset JO 3 Structural

Joint Separated JS 4 Structural

Line Down LD 1 Other

Lining Failure Abandoned Connection LFAC 1 Other

Lining Failure Blistered LFB 1 Other

Lining Failure Buckled LFBK 1 Other

Lining Failure Service Cut Shifted LFCS 1 Other

Lining Failure Detached LFD 1 Other

Lining Failure Defective End LFDE 1 Other

Lining Failure Overcut Service LFOC 1 Other

Lining Failure Undercut Service LFUC 1 Other

Lining Failure Wrinkled LFW 1 Other

Lining Failure Other LFZ 1 Other

Line Left LL 1 Other

Line Left/Down LLD 1 Other

Line Left/Up LLU 1 Other

Line Right LR 1 Other

Line Right/Down LRD 1 Other

Line Right/Up LRU 1 Other

Line Up LU 1 Other

Miscellaneous Camera Underwater MCU 1 Other

Miscellaneous Direction Change MDC 1 Other

Miscellaneous General Observation MGO 1 Other

Miscellaneous General Photograph MGP 1 Other

Miscellaneous Joint Length Change MJL 1 Other

Miscellaneous Lining Change MLC 1 Other

Miscellaneous Material Change MMC 1 Other

Miscellaneous Repair Recommendation MRR 1 Other

Miscellaneous Survey Abandoned MSA 1 Other

Miscellaneous Dimension/Diam/Shape

Change MSC 1 Other

Miscellaneous Survey End MSE 1 Other

Miscellaneous Survey Start MSS 1 Other

Miscellaneous Tunnel Condition - Fair MTC 1 Other

Miscellaneous Tunnel Condition - Good MTG 1 Other


Miscellaneous Tunnel Condition - Poor MTP 1 Other

Miscellaneous Water Level MWL 1 Other

Miscellaneous Water Mark MWM 1 Other

Miscellaneous Dye Test MY 1 Other

Obstacles/Obstructions Brick or Masonry OBB 1 Operational

Obstacles/Obstructions Object Thru

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Obstacles/Obstructions Object Protruding

Thru Wall OBI 1 Operational

Obstacles/Obstructions Object Wedged in

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Obstacles/Obstructions Pipe Material in

Invert OBM 1 Operational

Obstacles/Obstructions Construction Debris OBN 1 Operational

Obstacles/Obstructions External Pipe/Cable

In Sewr OBP 1 Operational

Obstacles/Obstructions Rocks OBR 1 Operational

Obstacles/Obstructions Built Into Structure OBS 1 Operational

Obstacles/Obstructions Other Objects OBZ 1 Operational

Obstacles/Obstructions Drop Pipe ODP 1 Operational

Roots Ball RB 1 Operational

Roots Fine RF 1 Operational

Roots Medium RM 1 Operational

Point Repair Localized Lining RPL 1 Other

Point Repair Patch Repair RPP 1 Other

Point Repair Pipe Replaced RPR 1 Other

Point Repair Other RPZ 1 Other

Roots Tap RT 1 Operational

Settlement S 1 Structural

Surface Damage Aggregate Missing SAM 4 Operational

Surface Damage Aggregate Projecting SAP 3 Operational

Surface Damage Aggregate Visible SAV 3 Operational

Surface Damage (Metal Pipes) Corrosion SCP 3 Operational

Surface Damage Missing Wall SMW 5 Operational

Surface Damage Reinforcement Corroded SRC 5 Operational

Surface Damage Roughness Increased SRI 1 Operational

Surface Damage Reinforcement Visible SRV 5 Operational

Surface Damage Surface Spalling SSS 2 Operational

Surface Damage Other SZ 1 Operational

Tap Break-In/Hammer TB 1 Other

Tap Factory Made TF 1 Other

Tap Saddle TS 1 Other

Vermin Cockroach VC 1 Other

Vermin Rat VR 1 Other

Vermin Other VZ 1 Other


Weld Failure Circumferential WFC 4 Structural

Weld Failure Longitudinal WFL 5 Structural

Weld Failure Multiple WFM 5 Structural

Weld Failure Spiral WFS 5 Structural

Collapse Brick XB 5 Structural

Collapse Pipe XP 5 Structural

Appendix D Inspection Plan

1

D R A F T T E C H N I C A L M E M O R A N D U M

Inspection Plan for Lake Whatcom Tunnel PREPARED FOR: City of Bellingham

PREPARED BY: CH2M HILL

DATE: March 04, 2015

Introduction The purpose of this memorandum is to present the Tunnel Inspection Plan for the City of Bellingham’s Lake Whatcom Tunnel. The tunnel inspection is a key element in assessing the condition of the tunnel. The tunnel inspection is planned for April 22, 2015, beginning at 7am and will continue over the course of the day for up to 12 hours. The results of the tunnel inspection will be documented in a subsequent Condition Assessment Report that will identify and describe defects and present approaches and estimated costs for rehabilitation.

In support of the inspection effort, the City of Bellingham will close and lock out the slide gate at the Gate House at the upstream end of the tunnel the day prior to the inspection. Shutting the water off will leave the tunnel free of water and available for the inspection team. Once the inspection team is out of the tunnel, the City will open the slide gate to re‐establish supply to its downstream water treatment plant. The total duration the City can discontinue the water supply is approximately 24 hours.

This inspection plan addresses the following key topics:

Background Description of Tunnel

Inspection Methods and Approach

Key Inspection Activities and Chronology

Inspection and Safety Team

Equipment Requirements

Safety Concerns

Background Description of Tunnel The Lake Whatcom Water Supply Tunnel was constructed in 1939 and has been in continuous operation with only periodic shutdowns for maintenance and has a design capacity of 98 MGD. The tunnel is approximately 7,560 feet long and is constructed through sedimentary rock consisting primarily of shale. Record drawings indicate the tunnel was constructed using drill and blast methods forming a 6.5 foot horseshoe shape and has a cast‐in‐place concrete lining. The upstream invert elevation of the intake pipe is at 298.5 feet above sea level, and the downstream invert at the screening plant is at 290.94. The tunnel slopes at a uniform rate of 0.1%.

The function of the tunnel is to convey raw water from the Gate House at Watkins Point on the West shore of Lake Whatcom near the intersection of Lakeway Drive and Lake Whatcom Boulevard and extends approximately 1.5 miles west to the Screen House in Whatcom Falls Park on Silver Beach Road. Both tunnel entrances will be used in the field inspection and emergency access may be required for each. There is a shaft located on Euclid Road that may also be used for emergency access if required.

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Inspection Methods and Approach The inspection team shall employ the methods and approaches for inspection of the tunnel, as described in the subsections below. The inspection will begin at the downstream end of the tunnel (Screen House) and proceed to the upstream end of the tunnel (Gate House) as shown in Figure 1.

The inspection will be comprised of visual and non‐destructive methods. Tunnel defects will be documented using either paper inspection forms or electronic forms installed on an iPad or Tablet. Photographs will also be taken to document conditions in the tunnel.

The inspection will generally follow industry accepted practices and standards defined by the National Association of Sewer Service Companies (NASSCO) for documenting defects. In addition to visually identifying and documenting, the inspection will include the following specific tasks:

Identify changes in the tunnel lining material and/or geometry, if any.

Perform sounding of lining using a 5 pound maul to determine void or separation from rock in locations where visual indications suggest this may be occurring.

Identify locations of water infiltration either through weep holes constructed for that purpose (if any) or through defects in the lining.

The inspection team will make continuous measurement of distance from the tunnel entrance at the Screen House by use of 100 foot tape or laser tape measure and markings applied by lumber crayon or by paint (if necessary and deemed safe) on the tunnel wall. Survey pins will be set on 100 foot stations to provide a permanent set of reference points – to aid future tunnel inspections or repairs.

FIGURE 1 Lake Whatcom Tunnel Alignment

Screen House

Gate House Intermediate Shaft

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Key Inspection Activities and Chronology The tunnel inspection will be conducted on April 22, 2015 and will continue throughout the day. The key

activities associated with the tunnel inspection on April 22, 2015 are presented below:

March 31, 2015 (3pm to 5pm) – Conduct a Pre‐Inspection Coordination Conference Call to cover safety issues, equipment needs, staffing needs, communications, schedule, and other topics related to the tunnel inspection.

April 21, 2015 (2:00pm at Screen House) – Conduct a Pre‐Inspection Coordination Meeting to review the same topics as addressed in the Pre‐Inspection Coordination Conference Call and undertake any necessary last‐minute tasks in order to ensure that the inspection begins promptly the following day.

April 22, 2015 (7:00am – 7:30am at the Screen House) – Arrival, unloading, and equipment check and organization at Screen House.

April 22, 2015 (7:30am – 7:45am at the Screen House) – Pre‐entry meeting covering safety, communications, schedule, coordination, and equipment checks.

April 22, 2015 (7:45am – 8:00am at the Screen House) – Complete final check of survey team and inspection team equipment prior to entering the tunnel.

April 22, 2015 (8:00am – 8:30am Screen House Tunnel Entrance) – Tunnel inspection and survey teams enters tunnel to evaluate, test, and select method for installing permanent stationing markers.

April 22, 2015 (8:30am – Complete) – Survey Team will install permanent stationing ahead of Inspection team in the tunnel.

April 22, 2015 (9:00am – Complete) – Inspection team completes final organization and begins inspection at Screen House while allowing survey team to get 30 minutes ahead regarding installing stationing.

Inspection and Safety Team The inspection and safety team are comprised of CH2M HILL staff, City of Bellingham staff, and Life Rescue staff. The technical inspection will be lead by CH2M HILL with monitoring and support from City of Bellingham staff. Life Rescue staff will continuously monitor each of the three tunnel access locations with two attendants, as described in the Tunnel Entry Safety Plan for the Lake Whatcom Tunnel Inspection. The tunnel inspection and survey support team entering the tunnel will be comprised of the following individuals, along with their roles:

Robert Martin/CH2M HILL – lead tunnel inspector

Dan Buonadonna/CH2M HILL – tunnel inspector

Jake Stick/CH2M HILL – permanent station installer

Josh Kennedy/CH2M HILL – permanent station installer

Bill Miller – City of Bellingham monitoring and support

Equipment Requirements The Lake Whatcom Tunnel inspection will require the equipment listed in the table below. In addition to the inspection, sustenance, and safety equipment listed in the table, it should be noted that each tunnel entrant shall be responsible for handling, removing, and packing out any human waste (urine, defecation, or

4

mucous) that must be expelled within the tunnel. Individuals shall use sealable plastic bags for containing solid waste and toilet paper and re‐sealable bottles for urine.

Item Equipment Type Responsible Party 1 Copies of Bellingham Tunnel Design Drawings CH2M HILL 2 iPad or Tablet with 10 hour battery life and backup battery charger CH2M HILL

3 Metal Clipboards with Hinged Covers (4) plus hard copies of field inspection forms and NASSCO codes as contingency CH2M HILL

4 Field Book - water resistant paper (each individual on site) CH2M HILL 5 Camera with backup batteries and charger (2 per inspection team) CH2M HILL 6 Backpack (each individual on site) Individual 7 Pencils and Pens (2 per individual on site) CH2M HILL 8 Black Felt Tip Permanent Marker (2 per inspection team) CH2M HILL 9 Steel 100-ft Measuring Tape or chain CH2M HILL 10 Steel, 20-ft Measuring Tape CH2M HILL 11 6-ft Folding Ruler - Optional (1 per inspection team) CH2M HILL 12 Large Plastic Heavy Duty Ziploc Bags (2 per inspection team) CH2M HILL 13 Garbage Bags (2 per inspection team) CH2M HILL 14 Yellow Kiel Chalk (2 per inspector) CH2M HILL 15 Florescent Orange and White Spray-paint (24 cans) CH2M HILL 16 Rock Hammer (1 per inspection team) CH2M HILL 17 5 pound maul (1 per inspection team) CH2M HILL 18 Pre-Labeled (100 ft increments) Survey Tags and anchors (2 sets) CH2M HILL

19 Cordless Hammer Drill with (4) 0.375 inch concrete drill bits and (2) additional batteries CH2M HILL

20 Survey Label Anchors CH2M HILL 21 VHF Radio (one plus spare for sentinels) Life Rescue 22 Hand held radios for use in the tunnel CH2M HILL 23 Air Horns (for each team in the tunnel and each portal) CH2M HILL 24 4-Gas Air Monitors (minimum of 2 in tunnel. One with each team) Life Rescue 25 Hard Hats, safety glasses, gloves Individual

26 Head Lamps and extra batteries (1 for each individual entering the tunnel, and 2 spare) CH2M HILL

27 High Powered Spot Lights with backup batteries (2 total) and LED stick flashlights (one per person) CH2M HILL

28 First Aid Kit CH2M HILL 29 Cyalume Glow Sticks (12 Hour) CH2M HILL 30 Hip Waders or rubber boots (1 per individual entering the tunnel ) CH2M HILL 31 Lunch and minimum 1 liter water (1 per individual on site per day) Individual 32 Hilti DX E72 Powder Actuated Nail Gun or Similar CH2M HILL

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Safety Concerns The Lake Whatcom tunnel is a confined space and manned inspection of the tunnel includes potential risks commonly associated with confined spaces. All tunnel entrants will have confined space training and confined space entry procedures will be followed. Personal protective equipment will be used.

The specific potential risks associated with the tunnel inspection include the following:

Hazardous air quality

Inundation from water

Lack of natural light

Limited radio and air horn communication

Emergency access/egress due to the long length of the tunnel and small openings at each terminus to the tunnel.

A detailed Tunnel Entry Safety Plan for the Lake Whatcom Tunnel Inspection document, which includes a Job Hazard Analysis (JHA) for the inspection are prepared under separate cover. This document contains the detailed safety procedures and issues associated with project and must be reviewed by each tunnel entrant and member of the safety team prior to the inspection.

Hazardous Air Quality. Mitigation measures to help reduce the risk include the use of hand held (4 Gas) air monitors. Air will be forced into the tunnel at the upstream end of the tunnel at the Gate House via a 10,000 cfm diesel powered blower. The diesel generator exhaust will be situated to avoid entry to the tunnel. If air quality falling below established action levels is encountered, the team will immediately exit the tunnel in the direction from which it entered.

Inundation. Flowing water in the tunnel is considered a low risk hazard. Water can only enter the tunnel via the upstream slide gate at the Gate House. The slide gate will be closed and locked out the day before the inspection to ensure the tunnel is free of water. The slide gate has previously been tested for water‐tightness and has proven to be water tight. The Owner and the PM will each have a lockout key. No locks shall be removed until all parties and equipment are accounted for that have entered the tunnel.

It is possible that groundwater via liner defects could be entering the tunnel. This condition would be mitigated with rubber boots. Rain jackets are advised to mitigate dripping water within the tunnel.

Lack of Natural Light. The tunnel will be totally dark for its entire length and artificial lighting will be needed to perform the work, navigate the tunnel, and recognize potential hazards. To mitigate this hazard, the following equipment will be used.

All entrants will have LED head lamps. Experience has shown that battery life is sufficient to last a typical work day, but fresh batteries will be installed each day and a full set of spare batteries will be carried by each entrant.

Inspectors will carry Rechargeable LED work lights with 4‐hour battery life. These lights won’t be used continuously, but will be used to assist examination of observed defects and for other purposes as needed.

Inspectors will carry smaller LED work lights as backup. These lights are energized by AAA batteries and carry a 4 to 8 hour charge life depending upon the setting.

Limited Radio and Air Horn Communication. Experience from previous tunnel inspections suggests that the range for radio communication will be quite limited, likely less than 700 feet. The ability for the inspection team to communicate with tunnel entrants using air horns for emergency signaling will also likely be limited. Nonetheless, the inspection team will carry air horns as a form of communication.

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Prior to entering the tunnel the inspection team and the tunnel entrants will agree upon a target time for the inspection team to finish their work for the day and exit the tunnel. Should the inspection team exceed the target time by more than one (1) hour, and no communication is established between the above‐grade safety team and the internal inspection, then emergency rescue procedures shall commence. Communication shall be made by each team and above‐grade safety team at the intermediate shaft when passing to give a status of the work.

Emergency Access and Egress. While the initial entry for inspection will be from the downstream end a the Screen House, emergency access and egress can be either from the Screen House, the intermediate access shaft in Euclid Park at (roughly 4,400 feet from the Screen House and 3,200 feet from the Gate House), and/or the upstream end of the tunnel at the Gate House. Access to the tunnel at each of these locations will include temporary ladders, a safety tripod/hoist, and rope to aid potential emergency extraction.

All members of the team are required to complete confined space entry training prior to arrival on site and entry into the tunnel. Orientation to the site will be completed at the beginning of the day along with a review of safety procedures and emergency procedures and required actions inside the tunnel.

Appendix E Lake Whatcom Tunnel Defect Distribution

488508

0+00 1+00 2+00 3+00 4+00 5+00 6+00 7+00 8+00 9+00 10+00 11+00 12+00 13+00 14+00 15+00 16+00 17+00 18+00 19+00 20+00 21+00 22+00 23+00 24+00 25+00 26+00

26+00 27+00 28+00 29+00 30+00 31+00 32+00 33+00 34+00 35+00 36+00 37+00 38+00 39+00 40+00 41+00 42+00 43+00 44+00 45+00 46+00 47+00 48+00 49+00 50+00 51+00 52+00

52+00 53+00 54+00 55+00 56+00 57+00 58+00 59+00 60+00 61+00 62+00 63+00 64+00 65+00 66+00 67+00 68+00 69+00 70+00 71+00 72+00 73+00 74+00 75+00 75+54

LEFT TOE

SPRING LINE

CROWN CL

SPRING LINE

RIGHT TOE

PLAN - STA 0+00 TO STA 26+00

LEFT TOE

SPRING LINE

CROWN CL

SPRING LINE

RIGHT TOE


26+00

26+00 52+00

SCREEN HOUSE

LEGEND

NOT REQUIRED

LOW

MEDIUM

HIGH

IMMEDIATE

LEFT TOE

SPRING LINE

CROWN CL

SPRING LINE

RIGHT TOE


REHABILITATION PRIORITY DEFECT SYMBOLS

HOLE VOID VISIBLE

HOLE SOIL VISIBLE

FRACTURE SPIRAL

FRACTURE MULTIPLE

FRACTURE LONGITUDINAL

52+00

MA

TC

H LIN

E S

TA 2

6+00, S

EE B

EL

OW

MA

TC

H LIN

E S

TA 2

6+00, S

EE A

BO

VE

MA

TC

H LIN

E S

TA 5

2+00, S

EE B

EL

OW

MA

TC

H LIN

E S

TA 5

2+00, S

EE A

BO

VE

GATE HOUSE

STA 0+00 TO STA 75+54

ACCESS SHAFT

INTERMEDIATE

DEFECT DISTRIBUTION

LAKE WHATCOM TUNNEL

Appendix F Summary of Locations of Holes and Voids

Contributing to High Priority Rating

Appendix F Summary of Locations of Holes and Voids Contributing to High Priority Rating

The specific locations of hole defects within the 100-foot segments contributing to the “high” rehabilitation priority are presented in in the table below.

Locations of Holes and Voids Tunnel Liner Station

Hole Defect Observed Start End 0+96 0+96 Hole Void Visible

15+32 15+33 Hole Void Visible 15+39 15+40 Hole Void Visible 16+28 16+29 Hole Void Visible 16+72 16+74 Hole Soil Visible 16+97 16+98 Hole Soil Visible 18+50 18+50 Hole Soil Visible 19+95 19+98 Hole Soil Visible 22+60 22+61 Hole Soil Visible 24+32 24+34 Hole Soil Visible 25+04 25+15 Hole Void Visible 25+05 25+05 Hole Void Visible 25+18 25+19 Hole Void Visible 25+43 25+43 Hole Void Visible 27+40 27+43 Hole Soil Visible 27+82 27+82 Hole Soil Visible 33+90 33+96 Hole Void Visible 34+56 34+57 Hole Void Visible 36+18 36+21 Hole Soil Visible 38+68 38+68 Hole Void Visible 42+96 43+02 Hole Void Visible 44+00 44+05 Hole Soil Visible 47+09 47+09 Hole Void Visible 47+59 47+59 Hole Soil Visible 47+96 47+96 Hole Soil Visible 48+21 48+22 Hole Soil Visible 48+23 48+23 Hole Void Visible 49+09 49+09 Hole Void Visible 49+60 49+60 Hole Void Visible 50+40 50+40 Hole Void Visible 50+47 50+47 Hole Void Visible 50+50 50+50 Hole Void Visible 50+60 50+60 Hole Void Visible 50+61 50+61 Hole Soil Visible 50+67 50+67 Hole Void Visible 50+97 50+97 Hole Soil Visible 51+06 51+10 Hole Void Visible 51+16 51+17 Hole Soil Visible 57+32 57+32 Hole Void Visible 58+20 58+20 Hole Soil Visible 59+17 59+17 Hole Void Visible 59+23 59+23 Hole Void Visible 61+73 61+75 Hole Soil Visible 62+75 62+75 Hole Void Visible 62+96 62+96 Hole Void Visible 63+25 63+25 Hole Soil Visible 64+52 64+53 Hole Soil Visible 67+43 67+44 Hole Void Visible 71+50 71+50 Hole Soil Visible 72+59 72+60 Hole Void Visible 72+64 72+64 Hole Void Visible 75+11 75+14 Hole Void Visible

WT0622151047SEA F-1

Appendix G Tunnel Inspection Reports

Tunnel Inspection Report For: Lake Whatcom Tunnel

Report Number: 1

Inspection Date: 04/23/2015

Start Time: 0907

End Time: 1800

Inspector Name: Robert Martin

1Tunnel Number:

Inspection

Station Start

Inspection

Station End

Code

Descriptor Modifier

Value

Inches

L

Circumferential

Location

At/From To

Image

Referance

Remarks

D WH

135 South 84th Street, Suite 400

Milwaukee, WI 53214

RECORD COPY

0 0 Miscellaneous Survey Start Time, 09:07

1 1 Miscellaneous Lining Change CIP Concrete

2 2 Miscellaneous Dimension/Diam/Shape Change 78 Horseshoe75.6

2 2 Access Point Other Special Chamber Screen House

3 300 Deposits Settled Other .5 Sand and Gravel

3 600 Surface Damage Aggregate Visible Surface Damage Mechanical Aggregate Visible 6 6

16 17 Fracture Longitudinal 4 40.3

16 17 Infiltration Dripper 4 4

17 17 Fracture Angular 11 50.3

35 35 Obstacles/Obstructions Built Into Structure 4 6 6 Plug









96 96 Hole Void Visible 1 1 12 12


96 96 Miscellaneous General Photograph 1 Hole


101 101 Obstacles/Obstructions Built Into Structure 4 3 3 1 Plug



138 138 Obstacles/Obstructions Object Protruding Thru Wall 9 3 12 12 Steel pipe

140 149 Fracture Angular 9 7 20.3

Report Printed 6/4/2015 Page 1 of 16


Report Number: 1


Start Time: 0907

End Time: 1800


1Tunnel Number:

Inspection

Station Start

Inspection

Station End

Code

Descriptor Modifier

Value

Inches

L

Circumferential

Location

At/From To

Image

Referance

Remarks

D WH


Milwaukee, WI 53214

RECORD COPY

202 208 Fracture Spiral 9 40.2




240 241 Lining Failure Other 1 12 3 4 Honeycomb6

240 241 Infiltration Runner 3 3 0.25 gpm


250 250 Fracture Circumferential 7 50.1

250 250 Infiltration Weeper 7 7











501 501 7 50.1

501 501 Infiltration Runner 4 4 3 0.25 gpm

508 509 Infiltration Weeper 5 5 Honeycomb


547 549 Lining Failure Other 24 12 12 4 Soft Concrete6


580 580 Fracture Circumferential 7 5




Report Number: 1


Start Time: 0907

End Time: 1800


1Tunnel Number:

Inspection

Station Start

Inspection

Station End

Code

Descriptor Modifier

Value

Inches

L

Circumferential

Location

At/From To

Image

Referance

Remarks

D WH


Milwaukee, WI 53214

RECORD COPY

730 730 Infiltration Weeper 1 5 Cold Joint














900 900 Miscellaneous General Photograph 5















Report Number: 1


Start Time: 0907

End Time: 1800


1Tunnel Number:

Inspection

Station Start

Inspection

Station End

Code

Descriptor Modifier

Value

Inches

L

Circumferential

Location

At/From To

Image

Referance

Remarks

D WH


Milwaukee, WI 53214

RECORD COPY






























Report Number: 1


Start Time: 0907

End Time: 1800


1Tunnel Number:

Inspection

Station Start

Inspection

Station End

Code

Descriptor Modifier

Value

Inches

L

Circumferential

Location

At/From To

Image

Referance

Remarks

D WH


Milwaukee, WI 53214

RECORD COPY






1532 1533 Hole Void Visible 2 12 5 5 66

1539 1540 Infiltration Gusher 7 7 1 gpm









1628 1629 Hole Void Visible 3 74




1658 1663 Fracture Spiral 9 50.1

1672 1674 Hole Soil Visible 4 24 5 5 7 Moving fines9



1697 1698 Hole Soil Visible 2 5 5 Moving fines8






Report Number: 1


Start Time: 0907

End Time: 1800


1Tunnel Number:

Inspection

Station Start

Inspection

Station End

Code

Descriptor Modifier

Value

Inches

L

Circumferential

Location

At/From To

Image

Referance

Remarks

D WH


Milwaukee, WI 53214

RECORD COPY




1848 1851 Point Repair Patch Repair 7 7 8


























Report Number: 1


Start Time: 0907

End Time: 1800


1Tunnel Number:

Inspection

Station Start

Inspection

Station End

Code

Descriptor Modifier

Value

Inches

L

Circumferential

Location

At/From To

Image

Referance

Remarks

D WH


Milwaukee, WI 53214

RECORD COPY















2432 2434 Hole Soil Visible 2 8 7 7 Moving fines5

2432 2434 Point Repair Patch Repair 6 7 7





2504 2515 Hole Void Visible 1.5 7 73

2505 2505 Hole Void Visible 4 3 32




2505 2505 Lining Failure Other 6 4 43

2507 2510 Lining Failure Other 7 24 7 8 8 Honeycomb15



Report Number: 1


Start Time: 0907

End Time: 1800


1Tunnel Number:

Inspection

Station Start

Inspection

Station End

Code

Descriptor Modifier

Value

Inches

L

Circumferential

Location

At/From To

Image

Referance

Remarks

D WH


Milwaukee, WI 53214

RECORD COPY



2543 2543 Miscellaneous General Observation 6 6 Pressurized water





2598 2608 Fracture Multiple 3 30.2













2740 2743 Hole Soil Visible 1 1 7 7 Moving fines









Report Number: 1


Start Time: 0907

End Time: 1800


1Tunnel Number:

Inspection

Station Start

Inspection

Station End

Code

Descriptor Modifier

Value

Inches

L

Circumferential

Location

At/From To

Image

Referance

Remarks

D WH


Milwaukee, WI 53214

RECORD COPY


2861 2861 Infiltration Gusher 12 12 0.5 gpm



















3045 3045 Lining Failure Other 9 9 3 3 9 Thin, Exposed Shale7









Report Number: 1


Start Time: 0907

End Time: 1800


1Tunnel Number:

Inspection

Station Start

Inspection

Station End

Code

Descriptor Modifier

Value

Inches

L

Circumferential

Location

At/From To

Image

Referance

Remarks

D WH


Milwaukee, WI 53214

RECORD COPY




3214 3259 Fracture Longitudinal 8 8 Offset, 0.1250.3








3292 3297 Lining Failure Other 4 6 65



3301 3302 Lining Failure Other 1 1 Soft Concrete4


3306 3306 Lining Failure Other 0.75 5 2 2 Honeycomb12

3306 3307 Lining Failure Other 12 10 11 Thin7












Report Number: 1


Start Time: 0907

End Time: 1800


1Tunnel Number:

Inspection

Station Start

Inspection

Station End

Code

Descriptor Modifier

Value

Inches

L

Circumferential

Location

At/From To

Image

Referance

Remarks

D WH


Milwaukee, WI 53214

RECORD COPY



3618 3621 Hole Soil Visible 6 5 5 Shale6



3646 3646 Miscellaneous General Observation Time, 15:07
























Report Number: 1


Start Time: 0907

End Time: 1800


1Tunnel Number:

Inspection

Station Start

Inspection

Station End

Code

Descriptor Modifier

Value

Inches

L

Circumferential

Location

At/From To

Image

Referance

Remarks

D WH


Milwaukee, WI 53214

RECORD COPY











4359 4359 Line Left

4359 4370 Point Repair Other 7 5 10 Chemical Grout

4375 4375 Access Point Shaft Hole ( 3' or > ) 36 Time, 15:38






4403 4403 Point Repair Other 7 7 Chemical Grout

4405 4405 Infiltration Gusher 7 7 11 1 gpm, Moving fines

4408 4408 Infiltration Gusher 7 7 12 video 0.75 gpm

4449 4449 Point Repair Other 3 5 Chemical Grout

4453 4453 Obstacles/Obstructions Built Into Structure 3 3 Plug

4453 4453 Obstacles/Obstructions Built Into Structure 5 5 Plug






Report Number: 1


Start Time: 0907

End Time: 1800


1Tunnel Number:

Inspection

Station Start

Inspection

Station End

Code

Descriptor Modifier

Value

Inches

L

Circumferential

Location

At/From To

Image

Referance

Remarks

D WH


Milwaukee, WI 53214

RECORD COPY






4796 4796 Hole Soil Visible 2 6 5 5 Moving Fines3

4821 4822 Hole Soil Visible 2 12 5 5 Moving Fines5








5047 5047 Hole Void Visible 2 6 6 Under slab5



5050 5050 Hole Void Visible 2 6 6 12 Under slab5












Report Number: 1


Start Time: 0907

End Time: 1800


1Tunnel Number:

Inspection

Station Start

Inspection

Station End

Code

Descriptor Modifier

Value

Inches

L

Circumferential

Location

At/From To

Image

Referance

Remarks

D WH


Milwaukee, WI 53214

RECORD COPY

















5900 5900 Miscellaneous General Observation Time, 17:03













Report Number: 1


Start Time: 0907

End Time: 1800


1Tunnel Number:

Inspection

Station Start

Inspection

Station End

Code

Descriptor Modifier

Value

Inches

L

Circumferential

Location

At/From To

Image

Referance

Remarks

D WH


Milwaukee, WI 53214

RECORD COPY










6250 6250 Surface Damage Aggregate Visible Surface Damage Mechanical Aggregate Projecting 3 3 3 Spalled8









6522 6545 Fracture Multiple 3 30.2











Report Number: 1


Start Time: 0907

End Time: 1800


1Tunnel Number:

Inspection

Station Start

Inspection

Station End

Code

Descriptor Modifier

Value

Inches

L

Circumferential

Location

At/From To

Image

Referance

Remarks

D WH


Milwaukee, WI 53214

RECORD COPY





7511 7511 Point Repair Patch Repair 7 5 Recent ?


7511 7514 Hole Void Visible 7 9 11 Large Void

7545 7545 Miscellaneous Dimension/Diam/Shape Change 65 Flare out

7553 7553 Access Point Shaft Hole ( 3' or > ) 30 Gate House

7554 7554 Access Point WW Access Device 72 Slide gate70

7554 7554 Miscellaneous Survey End Time 18:00


lake whatcom tunnel condition assessment report

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