Prioritizing%20Booster%20Pump%20Station%20Improvements

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Prioritizing Booster Pump Station Improvements

• Tom Peters, P.E.May 2, 2008

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City of Bellevue WBPS Evaluation Overview

• Owns and operates 23 major water booster pump
  stations
• Pumped water service for over 60 of customers
• First overall technical evaluation of all pumping
  facilities and equipment

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City of BellevueWBPS Evaluation Project Goals

• Efficient distribution of maintenance dollars
• Identify facilities whose failure significantly
  impacts system reliability
• Rank WBPS in order of needed improvement
• Develop costs to upgrade and Improve WBPS
  reliability
• Asset management building block

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City of BellevueWBPS Evaluation History

• Grown from merger and assumption of old water
  districts
• Some facilities developer constructed
• Historically wholesale water purchase from City
  of Seattle
• Member of Cascade Water Alliance

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City of Bellevue WBPS Evaluation Project
Challenges

• Multiple pump types
• Varying levels of building quality
• Below grade vaults
• Inefficient location of emergency power
• Absence of re-chlorination facilities

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City of Bellevue WBPS Evaluation Project
Challenges
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Pump Station Information and Data

• Thorough review of as-builts, maintenance
  records, water production and previous studies
• Analysis of peak and average day consumption, by
  pump station and operating zone.
• Rigorous assessment of each pump station
  condition, with video taped operator interview
• Development of 10 system schematics summarizing
  basic system information

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Ranking Pump Stations
Paired Comparison Normal Operation
Ranking WBPS Needs
Paired Comparison Emergency Operation
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Ranking Evaluation Criteria
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Pump Station Score Card
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Normal Operating Ranking
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Ranking Pump Stations
Paired Comparison Normal Operation
Ranking WBPS Needs
Paired Comparison Emergency Operation
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City of Bellevue WBPS Evaluation Risk Based
Assessment

• Risk
• Hazard Probability X Vulnerability X Consequence
• Hazards impacting multiple facilities pose the
  greatest risk
• Regional power outage
• Earthquake
• Flooding
• Redundancy, properly placed, provides effective
  mitigation

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Sample Risk Ranking
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Emergency Operating Scenario
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Combined Rankings
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SUMMARY

• WBPS assessed 23
• WBPS requiring improvements 21
• Total cost all improvements 21.4 M
• Average cost of replacement (5) 2.9 M
• Average cost of improvements (16) 0.43 M