6521 EVERGREEN WAY 2016-01-01 MF Import

�---_... _ ��U� I� c� I�5 G. � ' , J�� ' �� ► �°`�� SWALG CALCS. 14-Ju1-94 16:14 EVER�TT DAIRY QU�EN--EVERGREEN WAY, LSA 3146 ___________________________________________ Contributory area = 1.01 acr.es Time of Concantration: Total Flow len. Vert. Ground Type Runoff Time of Time ft Drop Slope Cover Vel. Travel 10.0 _______________________________________________________ 360 7.0 1.94� paved 2.81 2.1 12.14 Time of Concentration, T(c) minutes = 12.14 Des. storm: 2 year recurrence, Itc in/hr = 0.945 Des. storm: 25 year recurrence, Itc in/hr = 2.050 Area, A acres = 1.015 , A sf = 44200 ------------------------------------------ landscaping 0.25 x 4400 sf Driveway/parking 0.90 x 39800 C = 0.835 Flow, Q cfs= (Itc x A x C) = 2 year Flow, Q cfs= (Itc x A x C) = 25 year Calculating_flow_through_a_swale: Friction factor = 0.200 Side slope = 3.000 H: 1V Channel slope = 0.0134 ft/ft Bottom width = 3.oU0 ft Swale length = 16o ft Deptb. Top feet Width ft ---------------- 2 year storm: 0.45 5.70 Area Wetted HYDR SF Perim RADTUS R � S ('7 U 1� o.aoi G'Z = C' �3' i.�3s Qzs = G, 5 b � �5 � c5 . o�G� VZ '= G� 3 l.��s � f5 ; c i'/� U' -i1 J'Y�.f- _�i �- M�n �y F,-, i vo � �lL� � Cl � 3' 1�p5 , Ic�Sal.. ----- ---------------- -- 1.96 5.85 0.33 need Q = Q Vel. Resid. cfs fps Time min. -------------------- 0.82 0.42 6.4 0.80 25 year storm: 0.67 7.02 3.36 7.24 0.46 1.74 0.52 5.2 need Q = 1.74 --------------------------•-------------------------------------------- If the ��weighted average" residence time is considered, roughly computed as follows (for the 2-year storm only): Area of site draining through 10o feet of swale: as a percent of total = Residence time for 100 feet of swale = Weighted average residence time = 9000 sf 20.4% 4.0 minutes 5.9 minutes .