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66” Water Main Break on River Roadand PCCP Program

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River Road 66-Inch FailureTimeline

:• December 23:

• Water Main Failed at 7:50am• CCT Emergency Call Center Notified Internal WSSC,

Both County Fire Boards and Health Departments• Main Shutdown• Ross Contracting Awarded Contract for Repair

• December 24: • Pepco Completed Power Line Repair• Ross Started Pipe Repairs

• December 24-26: • Washington Gas Repairs 24-inch Gas Main

• December 26: • WSSC Internally Inspected 1600 ft. of 66-Inch

• December 30: • WSSC Internally Inspected additional 400 ft. of 66-Inch• Repairs/Cleaning of Cabin John Branch

• December 31: • Completed pipe repairs, began chlorination

• January 1:• Opened River Road at 3:00pm

• January 7: • Water samples passed lab test• 66-Inch Main Back in Service at 5:30pm

• January 8:• Completed remaining restoration work, • Contractor demobilized

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WSSC Water Transmission and Distribution System

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Sustainability Plan by Pipe Size

• Composition and Miles of Pipe in WSSC System/Life Cycle• Pipe < 16”-- about 4500 miles of Ductile, Cast Iron, Unlined Cast Iron• Pipe > 16”– about 1000 miles of Steel, Cast Iron, Ductile Iron, PCCP• Life Expectancy--60 Years for Unlined Cast Iron• Life Expectancy--75-100 Years for Steel, Ductile Iron, Cast Iron, PCCP

• Inspection/Monitoring/Repair/Replacement• Pipe < 16”: Current Water Reconstruction Program

• Ramp up to 60 miles a year• Repair/Replace Based on Age, Maintenance History, Fire Flow Issues

• Pipe 16” – 36”: Adding to our Water Reconstruction Program• Ramp up to 15 miles• Cast Iron has low break rate, but aging is factor now

• Pipe Above 36”: Inspection and Monitoring are Key- Iron -- Corrosion control, Valve & Fire Hydrant MX- PCCP -- Problematic; Fails Catastrophically Without Warning

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PCCP Program History

• 1981--PCCP Condition Assessment and Inspection Program began--first used Visual and Sounding to identify deteriorated areas and delaminations

• Late 1980’s--WSSC worked with consultants and studied applicable non-destructive testing methods

• Mid-1990’s--Sonic/Ultrasonic Pulse Echo was adapted to PCCP and added to the Program--identifies micro-cracking and concrete out of compression.

• 2001--Electromagnetic (RFEC/TC) testing was added to the Program--estimates number of broken pre-stressing wires in each pipe section

• Early 2007, permanent Acoustical Fiber Optic (AFO) monitoring first installed-- monitors wire breaks following a baseline condition assessment

• In late 2008, acoustical leak detection methods were added to the Program to be performed prior to dewatering for the inspections

• Approximately 116 miles internally inspected to date; AFO currently installed in 16.9 miles

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PCCP Inspection History

PCCP Inspection History

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PCCP>/= 54 inches 48 inch PCCP

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PCCP Current Program

• WSSC has a total of 357 miles of Pre-stressed Concrete Cylinder Pipe (PCCP) Water Mains including:

– 57 miles – 54” and Greater– 86 miles – 36” through 48”– 214 miles – 16” through 30”

• Annual inspection plan is based on risk rating assigned to 36” and larger (143 miles)

– Risk rating based on pipe diameter, age, land use, operational criticality, repair history and date last inspected

• Program focuses on mains 54-inch and greater--considered a higher risk due to their diameter, operational criticality, and highest consequence of failure

• Current state of the industry for non-destructive PCCP inspection techniques requires manual operation and manned entry into the pipelines to perform the inspections     

• Virtually all WSSC PCCP water mains 54-Inch and greater have been inspected 1-3 times; the more problematic mains have been inspected 4-5 times

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PCCP Current Program

• Inspection includes visual and sounding, sonic/ultrasonic, electromagnetic survey, acoustical leak testing, long term acoustical monitoring

• Establishes baseline condition, locates leaks, identifies needed repairs/replacements and planning for long term capital replacements

– Engineering analysis done to determine if deteriorated pipes require replacement or can be repaired with carbon fiber internally or tendons externally

– Permanent acoustical monitoring listens for additional wire break activity as early warning sign and establish rate of deterioration

• Inspections take 2-3 months to perform

– Shut down and dewater pipeline during colder months September through June when demand is lower

– During higher water main break season

• Cost per 12 miles for inspection and installation of Acoustical Fiber Optical Monitoring – $3 M

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Inspection Interval and Annual Mileage

• Preferred inspection interval for PCCP pipelines is 5 to 10 years; 5 years for 48” and above to 10 years for below 48”

• FY’07 and FY’08 PCCP Program mileage budget was 6 miles inspection and 6 miles of installation of Acoustical Fiber Optic (AFO) monitoring; results in inadequate and high risk 12 year inspection interval

• At 12 miles per year, the 48” and larger pipelines would be on a near optimum inspection interval of 6 years 

• In FY’09, the Counties approved budget supplement to increase the PCCP mileage to 12 miles inspection miles and AFO installation 

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Five Year Plan

• FY’09 – 12 Miles – 1)Project 80 96-Inch and 2)River Road 66-Inch

• FY’10 – 12 Miles – 1)Rock Creek 54/60-Inch and 2)Failed Mont. Co. 48-Inch

• FY’11 – 12 Miles – 1)Mont. Co. High Zone 60-Inch and 2)White Oak 72-Inch

• FY’12 – 12 Miles – 1)Prince George’s 54/60-Inch Supply Main, 2)Brightseat 54-Inch 3) I-270

• FY’13 – 18 Miles – Mains less than 48-Inch

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Looking Ahead

• To close gap created by reduced inspection program in FY’00 to FY’06, increase mileage goals to 18 miles FY’12- FY’13 for 48” and larger

• Steady-state inspections of 12 miles resumes in FY’14

• FY’11 CIP – Study/Design for Rehabilitation of 60-Inch Adelphi Main

• For diameters smaller than 48-inch, technology developments (estimated at FY’12 and beyond) may allow:

• Unmanned inspections with the pipe full/partially full of water using current methods adapted to smaller pipe

• May not require acoustical monitoring, be done at a lower cost in a shorter timeframe and at a 10 year interval

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Advancing Electromagnetic Techniques for PCCP < 48-Inch

Robotic (Unmanned) Electromagnetic P-Wave for Small Diameter PCCP (<

48”)for use in Submerged Conditions

Adaption of Current

Technology to Diameters less than 48-inch.

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Small Diameter Underwater Adaptable Visual Inspection Tool

Unmanned Underwater Small Diameter (< 48”) Pipe Visual Inspection Tool – Adaptable to other

Technologies

Fiber Optic Communication

Cable/Tether High Power Lighting and

Cameras

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Sustainable PCCP Program

• A sustainable PCCP Inspection and Condition Assessment Program is Critical to the Mission of WSSC

• A component of WSSC’s Infrastructure Renewal Plan

• Ensures timely inspection and repair of deteriorated pipe sections

• Provides safer, more reliable water supply

• Helps ensure the pipelines reach their intended useful life

• Provides condition assessment for long term capital planning

• Program must be a top budget priority and funded annually to assure public safety and reliability of the water supply

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