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i <br /> I5.2 Flow Control System <br /> i Water quality treatment is nof required. Tmatment from proposed pollution-genereting <br /> impervious and pervious surfams will take place at the sewage treatment pianf. <br /> � Email from City oF Everett: <br /> IFrom: DaveVoigf/mnilfo:DVoigt@ci.cverefLwa.us� <br /> Sent: Monday, November 10, ZOOR 3:07 PM <br /> fTo: Melvin Carden;Souheil Nasr <br /> � Cc: Jane Zimmerman <br /> Subject Evtt CCTopper Lot&Gym sites <br /> IMelvin, <br /> Dased on the in�ormation you provided and our bricJdiscussion todny, [he proposed <br /> � improvements arc not much different than fhe existing/original development in tcrnu o/ <br /> I impervious surJace and stormwater runoJ/. We understand that sformwatcr�vill be <br /> rou[ed to the same oJfsite conveyance pipe system as [he existing/original developrnent <br /> did. !ant not a�vmc that the exis(ing/originnl development had ony stnrmtvn[er <br /> Idefenfion or rctenfion facilitiet. <br /> i <br /> Dave <br /> � <br /> '� David Voi�t, P.E. <br /> ScniorEnginccr, Projrrt Mm�ngcr <br /> I City of Evcrett, Pablic Waiks <br /> Phane 425-257-8983 <br /> Fax:425-257-8882 <br /> � Email:dv�t�ci_e❑_erelL�va.us <br /> 5.3 Conveyance System Analysis and Desigrr <br /> IThe project conveyance system consists of an 8-inch diameter closed drainage pipe system that <br /> connects to a city 8-inch concrete combined sanitary/storm sewer pipe in Broadway Avenue. Sce <br /> � Appendix A, Exhi�it 2B. <br /> The Rational Method was used to check peak Flow capacity and size conveyance pipP;. <br /> Precipitation intensity values were taken from the City of Everett Stormwater Management <br /> I Manual, Figure 1-5.1 (see Appendix A, Exhibit 6 of this report). The maximum values were used <br /> for conservancy. All drainage basins were calnilated based on a minimum time of concentralion <br /> of G.3 minutes. The individual pipe runs were calculated by Manning's Equation. (Dasin <br /> � calculations and Haestads Methods printouts are included below). See Appendix A, Exhibit 4. <br /> The pipe system was checked for minimum velocity for the 25-year s[orm. All system <br />� components have a design velocity of at least 2 fps for Uie design storm. Pipe capaciry was <br /> � analyzed for capacity for tlie 100-year storm. No backwater analysis was performed because all <br /> pipes within the system fwution al or belo�v 50 percent depth far [he 100-year storm. <br /> I <br /> ISlorm�valer Site Plan �Q : O <br /> Everett Commm�ity College <br /> Topper Paikin9 Lo[ '� -�y�.� <br /> � 7U8721.10 � <br />