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<br />II <br />il <br /> <br />,I <br />'I <br />II <br />'I <br />I <br />I <br /> <br />--~ <br /> <br />II <br />~ <br />~ <br />II <br />- <br /> <br /> <br />~ <br />II <br />. <br /> <br />'I <br />. <br /> <br /> <br />LI <br />'I <br />. <br /> <br />:11 <br />II.: <br />LI <br /> <br />1 <br /> <br />EGL for incoming pipes will coincide. An iterative process <br />of increasing the pipe size of a reach if the HGL is too high <br />and decreasing the size if the pipe is not full or nearly full <br />will optimize the system operation and cost. A minimum velocity <br />. of two feet per second should be maintained for flows from the <br />five year storm. <br /> <br />Standard equations for estimating energy losses are as <br />follows: <br /> <br />1. Friction slope: <br /> <br />Sf <br /> <br />= (~4/3)( <br /> <br />v2 ) <br />2g <br /> <br />where: <br /> <br />Sf = slope of EGL, feet/foot <br />R = hydraulic radius, feet <br />V = velocity, feet/second <br />9 = acceleration of gravity, feet/second2 <br />K = constant for type of pipe, = 0.906gn2 <br /> <br />n = Manning's roughness coefficient <br /> <br />For pipes not flowing full, adjustment for actual velocity <br />and hydraulic radius can be made with the use of Figure IV-4. <br /> <br />2. Transitional losses, ht: <br /> <br />(al For V2 > VI: <br /> (V22 V12) <br />ht = 0.1 --- <br />2g 2g <br />(b) For VI > V2: <br />ht = 0.2 (V12 _ V22 ) <br />2g 2g <br />where: <br /> <br /> VI = upstream velocity <br /> V2 = downstream velocity <br />3 . Bend Losses hb: <br /> hb = 0.25 fiv2 <br /> 90 29 <br /> 43 <br />