SU0013949 - Laserfiche WebLink

Home Browse Search

River Islands Development at Lathrop January 2021 Final River Islands Potable Water Technical Report—Rev 3 #6520 The following areas did not have finalized improvement plans and the assumptions listed above were utilize in order to model these demands. The total number of dwelling units or acreage of these areas was assigned based on projected quantities provided by River Islands. Ultimately, the model results should be revisited when the improvement plans for these areas become available. Please reference Appendix A for the location of these areas. • Employment Centers in Phase 1 B • Town Center in Phase 1 B • Village R in Phase 1 B • Village CC in Stage 2A • Village X in Stage 2A • Village KK and II in Stage 2B • All of Phase II 4.1.2 Fire Flow Analysis WaterGEMS has a fire flow analysis feature which determines the available fire flows under steady-state conditions at each junction or hydrants at a time. The available fire flows at a single junction/hydrant are determined after system wide demands have been satisfied and as long as specific operating criteria are satisfied. In other words, the fire flow analysis determines the available fire flows for a single fire event if it were to occur at each of the selected junctions or hydrants. Per Section 6 in City's Water Master Plan, the following operating constraints/requirements were inputted into the fire flow analysis. • The calculated available fire flows must also be provided in conjunction with the baseline demands. o For the purposes of seeing the performance of the system, fire flows were analyzed in conjunction with MDDs as required by the City requirements. • A minimum residual pressure at each junction or hydrant tested must be greater than or equal to 20 psi as fire flows are being extracted. • A minimum system wide pressure at each junction or hydrant must be greater than or equal to 20 psi during fire flow analysis. • The fire flow analysis shall simulate one 4,000 GPM fire flow event at each of the tested junctions or hydrants. If 4,000 GPM cannot be provided the model will determine the maximum available fire flows. o For the purposes of seeing the performance of the distribution system, the upper limit of the fire flow analysis was set at 4,000 GPM, even though the highest fire flow requirement for River Islands is 3,000 GPM. This will allow for future planning if the parcel's land uses are reclassified. • The maximum velocity in any distribution (non-service lateral) and transmission pipe shall not exceed 10 feet per second. 16