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calculation sheet. <br /> Column 3: <br /> Flows are cumulated in DI's according to configuration. <br /> Col 4, through 12: <br /> Pipe diameters are chosen based on flowcapacity, grade and velocity <br /> considerations. A general constraint of the system is that it must be configured as <br /> flat as possible to minimize the need for lifting flows to the relatively shallow <br /> basin. As indicated in the criteria, pumping is limited to the low areas in the <br /> recycling storage area and transfer tunnel. <br /> A Manning formula hand calculation nomograph wheel (by J.M. manufacturing) <br /> was used to calculate depth of flow in the pipe (9), velocity (12), HGL in each <br /> pipes (10) assuming that the outlet was unsubmerged at the pond. After these <br /> numbers are obtained, the sheet indicated the HGL (11) in the pipe branches by <br /> calculating the HGL moving upstream assuming that the HGL is the highest of <br /> individual pipes calculated at junctions. (Note that column 11 calculates HGL <br /> moving upstream only considering rise and depth of flow in pipe and not the <br /> highest HGL at junctions). <br /> It should be noted that minor losses were not considered in all HGL calculations. <br /> HGL calculations only used elevation changes from the slopes of pipes to <br /> calculated HGL. <br /> t ed from 1. I-2 to 5.0 DI-8&9 feet per second. <br /> Velocities calculated rang ( ) ( ) <br /> Col 13 and 14: <br /> The travel time in pipes, based on calculated velocities is in column 13. Column <br /> 13 shows total travel times to the point of concentration, including the 10 minute <br /> initial concentration times assumed in peak runoff calculations on sheet 1 of 2. <br /> The maximum total time is 16 minutes. It should be noted that the rainfall <br /> intensity for 16 minute duration (approximately 2.1 inches per hour) versus the 10 <br /> minutes duration (10 minutes 2.22 inches per hour - see IFD) used for peak flow <br /> calculations is not significantly less. Therefore additional flow time in pipes was <br /> conservatively neglected for peak flow calculations and sizing of the pipes. <br /> Col 15 and 16: <br /> Column 15 and 16 show grate elevations and cover depths from the crown of the <br /> pipe (pipe diameter added to invert elevation) to the grate. Cover calculations <br /> range from 1.9 feet to 5.5 feet. Due to the limited cover in areas, Class IV RCP <br /> piping (at request of County Solid Waste Division) will be used. <br />