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Flows in excess of 6,000 cfs (total flow) for 3 days in 2 out of every 3 years were also <br />analyzed for the 60 year period to quantify the number of occurrences of these flows and <br />to evaluate the contribution of the modeled EA releases. The number of days the flow at <br />Overton exceeds 6,000 cfs is summarized for each year in Appendix 3. The results of this <br />analysis are: <br />• Flows in excess of 6,000 cfs occur for durations of 3 days or more for 18 years of <br />the 60 year period (aggregating all year classifications). This is approximately <br />equal to 1 year in 3, in contrast to the target of 2 years in 3. <br />• Flows in excess of 6,000 occur 6 times in Average years, 12 times in Wet years, <br />and no times in Dry years. <br />• On occasion, EA water contributes to the flow in excess of 6,000 cfs. However, <br />the flow is never entirely EA water. <br />• Most occurrences of these target flows are a result of historical flows. The 3 days <br />or longer duration is always a result of historical events. <br />For the second flow objective, 800 cfs of Program water during the May through <br />September irrigation season, the following results correspond to Table 3-9 and Appendix <br />3: <br />800 cfs ProgLam water - Cases I and II: <br />The 800 cfs of Program water for May-September (153 days) is achievable on most days <br />for each year type assuming there were to be adequate EA water in storage at the start of <br />each year. Occasional shortages occur and vary in timing and magnitude among the six <br />scenarios (three year classifications and Cases I and II). The 800 cfs flow target equates <br />to a volume of Program water of about 243,000 ac-ft for the 153 day season from May 1 <br />to September 30. (If based on the period of May 11 to September 15 as outlined in the <br />Instream Flow Recommendations, the volume is about 200,000 ac-ft). (Releases from <br />Lake McConaughy in an attempt to meet this target range from about 280,000 ac-ft in <br />Wet years (Case II), to about 580,000 ac-ft in Dry years (Case II), when losses are <br />highest. Part of the flow target is met by yields of the Tamarack I project on the South <br />930wLE Page 37 of 58 <br />January 29, 2008 <br />PRRIP - Draft Water Management Study, Phase I