08 - Laserfiche WebLink

Happy Valley Water & Sewer Study Technical Memorandum each parcel were applied to the upstream end of the nearest pipe. Based on the results of this modeling, the existing sewers have sufficient capacity for flows under both Scenario I and Scenario 2. Hydraulic profiles for all affected gravity pipelines have been included in Appendix C. Hydraulic profiles included in Appendix C represent Scenario 2 flows; since no surcharge occurs under Scenario 2 flows, hydraulic profiles under Scenario I were not included. Profiles A to F include proposed new sewers, and Profiles G and H include only existing sewers that would convey flow from the Study Area. The proposed pipelines have been organized into seven projects for cost estimating purposes, as identified in Figure 6. Puma Stations and Force Mains Estimated flowrates and firm capacities for pump stations S -12 and S -14 are summarized in Table 5. The sewersheds assumed for each force main are identified in Appendix C. Pump station capacities were estimated based on pump curves provided by the City and a force main Hazen Williams coefficient of 100. The existing force main attached to the S -14 pump station is 4 -inch diameter. As the City requires a 6 -inch minimum diameter for force mains, it has been assumed that the 4 -inch pipeline would be replaced with a 6 -inch force main. The capacity of the S -14 force main presented in Table 5 is based on a 6 -inch diameter pipe. Pump and system curves for each pump station are included in Appendix D. As indicated in the Table, both pump stations have adequate capacity to handle the projected PW WF from their respective tributary areas. Table 5: Pump Station Capacity Footnotes: I. Assumes existing 4" force main is replaced with a new 6' force main. November 2016 14