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<br />I' <br />II <br />I,' <br />i,' <br />,II <br />Ii! <br />I' <br />" <br />,i <br />i.: <br />I, <br /> <br />Existing Monthly Volume <br />Steady Flow Alternative - This <br />alternative integrates the concept <br />of monthly steady flows based on <br />current water delivery schedules. <br />Water would be released from the <br />dam at a constant rate during any <br />given month. The figure <br />compares steady monthly flow <br />operation (solid black line) with <br />water year 1989 operations. - <br /> <br />Fluctuating Flow <br />Alternatives <br /> <br />II <br /> <br />I <br />II <br />I <br />III <br />'il <br />:1 <br />II <br />I, <br /> <br />All of the fluctuating flow <br />alternatives would allow for some <br />use of peaking power. The <br />scheduling of annual and <br />monthly release volumes would <br />be determined using existing <br />practices. Releases may be <br />adjusted throughout the year in <br />order to avoid spills and balance <br />storage between Lake Powell and <br />Lake Mead. <br /> <br />'I <br />I: <br />II <br />ill <br />I, <br />I: <br />I <br />I <br />I <br />I <br />II <br /> <br />Low Fluctuating Flow <br />Alternative Under this <br />alternative, fluctuations would be <br />limited to a 5,000, 6,000, or 8,000 <br />cubic foot per second (ds) change <br />(or approximately a 3-foot river <br />stage fluctuation in the Grand <br />Canyon) over a 24- hour period. <br />The total change per day would be <br />a function of monthly release <br />volumes. Maximum flows would <br />be limited to 20,000 ds. Minimum <br />flows would be 8,000 ds between <br />7 a.m. and 7 p.m. and 5,000 ds at <br />night. Ramping rates would be <br />limited to 2,500 ds per hour for <br />increasing flows and 1,500 ds per <br />hour for decreasing flows, This <br />alternative closely approximates <br />the current interim operating <br />criteria. The figure compares the <br />Low Fluctuating Flow Alternative <br />(solid black line) with actual <br />operations for a day in July. <br /> <br />6 <br /> <br />32,000 <br /> <br />28,000 <br /> <br />24,000 <br /> <br />III <br />u.. <br />() <br />.5 <br />~ <br />u: <br /> <br />20,000 <br /> <br />18.000 <br /> <br />12,000 <br /> <br />8,000 <br /> <br />4,000 <br /> <br />o <br /> <br />Existing Monthly Volumes Steady Flow Alternative <br />(1 989 Cond~lon. - 8.2 mol onnual role...) <br /> <br />~ AcIuoI 1ll81l Oily Rqe <br />- SleIdy Flow AIIorndW <br /> <br /> <br />OCT NOV OEe JAN FEB MAR APR MAY ,JUN ,JUL "00 SEP <br />Water Year 1989 <br /> <br />A day In July under the LOW FLUCTUATING <br />FLOW ALTERNATIVE might look like... <br />40000 <br /> <br />30000 <br /> <br />i <br />- <br />ill 20000 <br />. <br />. <br />.. <br />lZ: <br /> <br />10000 <br /> <br /> <br />Low Fluctuating <br />Flow Alternative <br /> <br />o <br />.~.~.~.~ .~# q~ q~ q~ q~ q~ i' <br />~ . ~ ~ ~ ~ ~ . ~ ~ ~ ~ <br />~ <br />