Identifying the pipe discharge location is important for identifying the pumping distance, 

 overall length of pipe required, and whether booster pumps will be required. As discussed 

 previously, pipeline discharge should be no closer to the inlet than the westward extent of the ebb 

 shoal. According to Figure 14, this distance is approximately 2.4 km west of the west jetty. 

 Including the distance required to cross the inlet (approximately 245 m), overall pipe length 

 should be approximately 2,700 m. 



If similar equipment as used at the Indian River Inlet plant is desired, then two booster pumps 

 will be required (i.e., the primary booster at the operations building and one additional pump on 

 the downdrift beach) (see Appendix F). Rule-of-thumb guidance provided by Turner (1984) 

 states that the most appropriate location for placing the booster pump is at about 40 percent of 

 the line length. In this case, the booster should be located 1,080 m downcoast of the primary 

 booster pump. Alternatively, a single larger pump able to overcome the entire system head loss 

 may be used to avoid having to operate two pumps. Details showing the calculations for head 

 loss and pump power requirement are provided in Appendix F. The costs that follow assume 

 using two pumps. 



Operating time can be either daily (bypass plant is operated on a regular period each day), or 

 intermittent (bypass plant is used only when bypassing is needed). Intermittent operation may 

 include periods when the system is idle and times when the system operates continuously. For 

 Shinnecock," a daily operating pattern is assumed for the period between September (after Labor 

 Day) and May (before Memorial Day), not including weekends and holidays (approximately 251 

 days). Richardson and McNair (1981) suggest the following equation for calculating the 

 effective operating time (EOT): 



EOT = (NODxHD)[1.00-(RR + PB + ALM + RMP)] 



(7a) 



where 



EOT = effective operating time 



NOD = number of operating days per year 



HD = number of working hours in an operating day 



RR = repair/replacement correction factor (-=-100) 



PB = pump blockage correction factor (-=-100) 



ALM = absence of littoral material correction factor (-=-100) 



RMP = relocation of mobile pump assemblies correction factor (-=-100) 



58 



Chapter 5 Other Bypassing Studies 



