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<br />J <br /> <br />,2:':) <br /> <br />BIOLOGICAL AND CONFERENCE OPINIONS <br />DESCRIPTION OF PROPOSED ACTION <br /> <br />The FEIS (page 40) identified that under any alternative, "Grand Canyon sandbars that exist <br />above nonnal peak river stage would continue to erode, and backwater habitats within normal <br />stage would tend to fill with sediment." To correct this, most FEIS alternatives included <br />beach/habitat-building flows as "...scheduled high releases of short duration designed to rebuild <br />high elevation sandbars, deposit nutrients, restore backwater channels, and provide some of the <br />dynamics of a natural system." The FEIS also stated that "a test of the beach/habitat-building <br />flow would be conducted prior to long-term implementation of this element...." Additionally, <br />the beach/habitat-building flow would be conducted"., . only in years when projected storage in <br />Lake powell on January 1 is less than 19 maf (low reservoir condition)." <br /> <br />Reclamation proposes to conduct a test of the beach/habitat-building flow from Glen Canyon <br />Dam. On or about March 22. 1996, 4 days of constant 226-cubic meters per second (cms) <br />flow would begin. On or about March 26. flows would increase at a maximum rate of 113 <br />cubic meters per second per hour (cms/hr) until a maximum flow of 1275 cms is reached and <br />held essentially constant for 7 days. On or about April 2, flows will be decreased to 113 cms: <br />in the following manner: (1) Between the maximum release and 990 cms, releases would <br />decrease at a maximum rate of 43 cms/hr. (2) Between 990 cms and 560 ems, releases would <br />decrease at a maximum rate of 28 cms/hr. (3) Between 560 cms and 226 cms, releases would <br />decrease at a maximum rate of 14 ems/hr. The staggered down-ramping is to mimic the <br />reduction of flow after a natural flood. Discharge would be maintained al 226 cms for 4 days <br />(through April 7). The constant 226 cms release proceeding the 1275 cms release would perrnil <br />aerial photography and on-site evaluation of sedimentation patterns and' effects on other <br />downstream resources. Interim operations would resume at Glen Canyon Dam on or about Apnl <br />8. <br /> <br />Annual release volume for water year 1996 would be the same as during interim nows <br />However, 10 conduct the test flow, release volumes for the period March and April would be <br />increased 462.6 million cubic meters (cm), and 5 months would have from 61.7 million cm III <br />185.0 million cm reductions in release volumes. July volume would be increased 30.8 milhlln <br />cm. <br /> <br />An essential part of the test are the pre. post, and 6-month research and monitoring studies I~I <br />will be conducted by various research groups coordinated by Reclamation's GeES Group The: <br />proposed test flow will assess how flooding influences the river corridor's geomorphol'l~~. <br />biological and cultural resources, and ecosystem process. <br /> <br />Biological and Conference Opinions Glen Canyon BeachlHabila,-Building Flows 2/16/96 <br /> <br />~ <br />