Condition Assessment: City of Bellingham Supply System · 2015-06-16 · Condition Assessment: City...

Condition Assessment: City of Bellingham Supply System 2015 PNWS-AWWA Conference

2 Presentation Title

Presentation Topics

1. Background

2. Condition Assessment

1. Wood Stave Intake

2. Tunnel

3. Screen House

4. Pipelines

1. Industrial (48” CCP)

2. Municipal (66” steel)

3. Acknowledgements/

Questions

3 PNWS-AWWA 2015

City of Bellingham

• Population = 83,000

• 13 pump stations

• 13 storage tanks

• 400 miles of pipelines

• One supply system

– Lake Whatcom

– Wood stave intake pipeline

– Tunnel

– Screen House

– Industrial supply pipeline

– Municipal supply pipeline

Lake Whatcom

Supply

Facilities

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Water Supply System

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Wood Stake Pipe Intake

Wood

Stave

Pipe

Intake

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Wood Stave Intake

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Wood Condition

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Original Steel Rods and SST Bands

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Condition of Steel Rods

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Flange

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Sponge Inside Intake Pipe

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Wood Stave Intake: Results

• Wood in good condition

– Support structural components

– Stave pipe (interior and exterior)

• SST bands in good condition

• Original steel fasteners in fair condition

• Some original steel rods corroded to failure

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Tunnel

Tunnel

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Tunnel Inspection Activities

• Underwater Laser Scanning (2012)

• Man-Entry Inspection (2015)

• Tunnel Data Analysis

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Tunnel Profile

7,600 LF

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Tunnel Section

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Laser Scanning: Field Photos

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Laser Scanning: Data Gathered

5 ft

9 ft

3 ft

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Laser Scanning: Example Output

REFLECTION OF CRAWLER

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Laser Scanning: Interpretation

West

No Defect

s 81%

Mild 12%

Moderate 5%

Severe

2%

East

No Defect

s 68%

Mild 17%

Moderate 13%

Severe

2%

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Man-entry Tunnel Inspection

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Man-entry Tunnel Inspection

Stationing Crew

Inspection Crew

Insertio

n P

oin

t

Extra

ctio

n P

oin

t

23 PNWS-AWWA 2015

Man-entry Tunnel Inspection

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Tunnel: Results

• No major deformation

• Isolated liner defects

• Limited, minor fracture acceleration

• Next Step: Point repairs, monitoring plan

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Screen House

Screen

House

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Screen House

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Screen House Inspection Elements

• Traveling screen

• Slide gates

• Concrete structure

• Steel pipes

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Travelling Screens

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Slide Gate

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Internal Steel Pipe Condition

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External Steel Pipes Condition

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Screen House: Results

• Concrete structure in good condition

• Travelling screens in good condition

• Slide gates

– Heavy tuberculation

– Some corrosion loss

– Replacement needed

• Steel pipes (3) need rehabilitation

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Industrial Pipeline

Industrial

Pipeline

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Tiered and Adaptive Plan (TAP)

• Visual

• Corrosion Survey

Tier 1

• Test Pits

• Destructive Testing

Tier 2

• Specialty Tools

Tier 3

Lowest Cost, Identify Issues Higher Cost, Design Data

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Soil Corrosivity Mapping Along Industrial Pipeline

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Existing Cathodic Protection System

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Existing CP Test Stations

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Industrial Pipeline: Results

• Existing CP system is operational and

effective

• Condition assessment complete after Tier 1

• No further condition assessment warranted

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Municipal Supply Pipeline

Municipal

Pipeline

(Raw

Water)

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Tier 1 External - Soil Corrosivity

1,800

49,200

1,800

1,300

3,600

2200

16,300

2900

5600

1,000

10,000

100,000

0+00 2+00 4+00 6+00 8+00 10+00 12+00 14+00

Soil

Res

isti

vity

(o

hm

-cm

)

Pipeline Station

5 to 7.5 ft depth

Slightly Corrosive

Moderately Corrosive

Very Corrosive

Extremely Corrosive (<1,000)

Screen House

Trail at Silver Beach Road

Trail at WTP Access Road

ARV

WTP

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Tier 1 External -Stray Current Adjacent Industrial Supply Pipeline CP System

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Tier 2 – Internal Condition

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Tier 2 Internal – Concrete/Steel Pipe Joint

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Tier 2 Internal – Pipe Wall Thickness

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Tier 2 Internal - Pitting

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Tier 2 Internal – Coal Tar Lining

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Tier 2 Internal – Cement Mortar

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Municipal Pipeline: Results

• External Tier 1 Complete

– Corrosive soils

– Stray current

• External Next Step: Tier 2 Test Pits

– Evaluate coating/pipe condition

– Test for stray current

• Internal Tier 2 Inspection

– Coal tar enamel lining – excellent condition

– Minor corrosion at coating defects

– Localized repairs at few joints required

49 PNWS-AWWA 2015

Acknowledgments

50 Presentation Title

Thank You

Dan Buonadonna, PE

Daniel.Buonadonna@CH2M.com

Jerry Duppong

Jerry.Duppong@CH2M.com

Phil Martinez, PE

Phil.Martinez@CH2M.com

Bill Evans

bevans@cob.org