Resolution No. 4793 - Laserfiche WebLink

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7 RECOMMENDED PLAN 7.6 Identification of Project Phasing The recommended improvements identified in Table 7.5-1 form the basis for the development of a 20-year project list. To develop the project list, the t/ming of individual facility improvements had to be ident/fled so that the overall regional wastewater needs could be rnet without a deficit in capacity. For some of the recommended improvements, a phased approach would provide flexibility in the level of improvements made. For example, modifications to both the north and south aeration basins to convert them to a step-feed, plug-flow air-activated sludge system with anoxic selectors do not have to be complete in both basins to meet the/rdtial capacity needs. These modifications could be phased so that the south basra is mod/fled initially, and the north basin is modified when futtrre flow and loads demand additional capacity, although frorn an operational standpoint, having both basins configured the same would be simpler. A phased approach to constructing facilities provides a more stable ftmding process, delays tmnecessary capital investments until they are needed, and allows for potential re-evaluation to implement appropriate future technologies. Using this approach, the recommended improvements were broken down into individual projects according to the facility needs over the planning period. For each project component, a fact sheet was prepared that outlines the project name, project description, project justification, project driver, and project trigger. The fact sheets are provided at the end of this chapter. 7.7 Implementation Schedule Using the project fact sheets, individual improvement projects were consolidated into phases based on the project trigger, which defines when the project must come on line to address capacity, regulatory, or other facility needs. Adjustments to the timing of some projects were made so that large variations in annual capital improvement costs were avoided. This was done without compromising facility needs and the approach resulted in a relatively level cash flow requirement. The estimated cost of each phase is presented in Table 7.7-1. The est/mated total cost for the recommended improvements in all phases is approximately $144,000,000. The anticipated projects and estimated project costs that are packaged in each phase are summarized in Table 7.7-2. The project costs estimated for each of the phases are order-of-magnitude estimates for construction and non-construction in 2004 dollars. The accuracy of this type of cost estimate typically ranges from -30 percent to +50 percent. Costs are based on 10 percent for mobilization/demObilization, bonds, and insurance; construction contingency of 25 percent; and engineering, legal, and administrative (ELA) of 25 percent. Construction costs are based on previous cost estimates or bid tabulations from similar projects. Costs for individual processes include site work, piping, electrical, I&C, and contractor markups. The 25 percent construction contingency is intended to cover unidentified and/or unknown items such as construction dewatering and subsurface structural support of buildings or structures. The project phasing is shown in Figure 7.7-1, and represents the twelve initial project phases. Figure 7.7-1 does not show offsite projects, such as the improvements to conveyance pump stations, the SIWF, the Biocycle Farm, and the BMF facilities. Figure 7.7-2 shows the project phasing required if the High-Rate Clarification alternative is required by DEQ. This MW~C_7.0_REV&DOC 7-13