Laserfiche WebLink
1 WillowsApartrnrnts <br /> Drainage Sady <br /> r 09/16/2009 <br /> � <br /> 5. WATER QUALI'TY DESIGN CRITERIA (cont.) <br /> I <br /> TESC SEDIMENT TRAP DESIGN FOR CONSTRUCTION AREA <br /> ISediment Traps are siud per the Everett Stotmwatet Manual for small sites of less than <br /> three acres. <br /> � • Trap Surface Area, As= 1.2 Q2/Vsed <br /> • Qc=2-year design inflow for cleared site= 0.067 CFS appcox 0.1 CFS <br /> + • Vsed=velocity of inedium silt particle=0.00096 fps <br /> • Minimum storage depth shall be 2 feet. <br /> • Outlet shall be a CMP riser with washed gravel filter cone. <br /> ' • Length to width ratio is> 3:1. <br /> As= 1.2 Q2/Vsed = :.2 * 0.1/0.00096 fps= 125 SF <br /> , . Minimum Depth = 2.5' <br /> ( From Waterworks: 6-Month Developed flow rate=0.067 CFS <br /> � <br /> ( <br /> 1 <br /> I_ <br /> ' <br /> I_ <br /> I <br /> 1 <br /> 1 <br /> I <br /> . 10 PROJECT:05812 <br /> � <br />