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Happy Valley Water & Sewer Study Technical Memorandum 3 Water System Evaluation This section describes the evaluation process and results for extending water mains and associated facilities to parcels within the Study Area but outside current City limits. The City's existing water distribution system has sufficient capacity to meet the City's criteria for minimum pressures, maximum velocity, and allowable headloss under both scenarios. Distribution system modeling has not been performed. 3.1 Evaluation Criteria Evaluation criteria used in the development of facilities and cost estimates for the water system are described in this section. Evaluation criteria include sizing and siting criteria for new facilities needed to extend service, and the cost criteria used to estimate capital costs associated with implementation of those facilities. 3.1.1 Sizing and Siting Criteria All proposed pipelines are sized to convey peak flow conditions under both land use scenarios. Pipe sizing and flow criteria are presented in Table 1; and are based on the City's 1984 Water System Design Standards and recommendations in the 2004 Water Master Plan. Pipeline alignments are based on siting information from the Happy Valley Specific Plan and discussions with City staff. As noted above, it has been assumed that existing piping is sufficiently sized to meet City requirements. All proposed pipelines were evaluated for maximum velocity and headloss; flow rates through proposed pipelines have been estimated based on likely service locations and flow paths. 3.1.2 Cost Criteria A planning -level construction cost estimate for each water distribution system component has been developed. Costs are considered accurate within +(20 to 50)% and -(15 to 30) %, consistent with AACE International Class 4 estimate (Study or Feasibility Level). These estimates are suitable for budget forecasting, CIP development, and project evaluations, with the understanding that refinements to the project details and costs would be necessary as projects proceed into the design and construction phases. Unit capital costs are based on engineering experience, recent bid prices for similar projects (including the City's recent Recycled Water Expansion project), and RS Means'. Unit costs are indexed to the February 2016 Engineering News Record Construction Cost Index 20 Cities Average (10,182). Where appropriate, a sales tax rate of 9.5% has been applied. Allowances have been added for project - specific costs (such as mobilization and demobilization and traffic control for work in roadways). All unit costs are fully burdened (raw construction cost plus contractor markups, taxes, overhead and profit). Pipeline construction costs have been estimated based on separate unit cost items for the pipelines, joint restraints, fittings, pot - holing, traffic control, trench excavation, and re- surfacing. Cathodic protection for ductile iron fittings has also been included. Quantities are calculated based on the evaluation results or estimated based on RMC experience with similar sized pipeline installation projects. Pressure reducing station costs include separate unit costs for the pressure reducing valve, gate valves, and vault. Excavation costs are included in the estimated costs for pipeline construction. Implementation Costs and Allowances Implementation costs are defined as those non - construction costs associated with a project. These costs can include the following: ' RS Means Company. (2016). Homy Constnrction Cost Data, Kingston, MA, R.S. Means Co., November 2016