2006 Water Comprehensive Plan - City of Bellevue

Table 7-1Criteria for Prioritizing R&R ProjectsCriteriaSource of InformationBreak/Leak HistoryIn-field ObservationsPipe Material/Age and relationship to useful lifeCapacity of PipeImportance of Pipe for Fire ProtectionLeak Testing ResultsOther Work in CityCustomer ComplaintsImpact of Loss of Pipe on System OperationsOther Consequence of FailureMaintenance RecordsMain Observation ReportsGIS databaseDiameter of Pipe (larger pipes have higher capacity)Fire flow simulations with and without pipePilot leak testing programCIP schedules for sewer, streets, parks, etc.Maintenance/Customer Service RecordsHydraulic analysis with and without pipeGIS database (easements, hospital access, etc.)The importance of each of the criteria listed above must be evaluated, and relative weights forthe various criteria be developed. Ultimately each pipe in the system should be rated on eachcriterion and a weighted value developed. The relative priority for replacement of each pipe inthe system would then be developed through the use of the weighted values.RESERVOIR STRUCTURAL EVALUATION AND REHABILITATIONThe City of Bellevue has a capital improvement program in place to mitigate earthquake damageto water reservoirs and to maintain their function following seismic events. The programshould continue as noted below.In 1993, the City of Bellevue authorized Kennedy/Jenks Consultants to conduct a ReservoirSeismic Vulnerability Study. The study looked at 21 of the City’s 26 reservoirs. The study didnot include five recently constructed reservoirs (Horizon View 3a, Cougar Mountain 1, 2, 3, and3a) since they were built to current seismic design standards. The consequence of failure andthe seismic vulnerability of each reservoir in the study was quantified and a priority ratingassigned. Reservoirs with an overall priority rating of low or low to moderate were notconsidered for further analysis. To obtain a low or low to moderate overall rating, required thatthe reservoir have a low seismic vulnerability and/or low failure consequence rating. A total of12 reservoirs were identified as requiring more detailed analysis.In 1995, KCM completed detailed structural analysis of the three highest priority reservoirs.Based on those results, Bellevue has constructed seismic improvements at the Clyde Hill 465reservoir and has reconstructed both the Cherry Crest reservoir and the Meydenbauer 252reservoir.7-7