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Interim flows implemented on November 1,1991 as a temporary measure to reduce the adverse change on downstream resources resulting from dam operations will remain in effect until the Record of Decision is implemented. Reclamation proposes to conduct a one-time test of a beachthabitat- building flow from Glen "Canyon Dam in the spring of 1996 to allow for collec- tion of data for use in determining future dam operations. The test flow will begin on or about March 22, 1996. The first four days will consist of a constant 8,000 cfs flow. On March 26, 1996, discharge will be increased at an upramping rate of 4,000 cfs per hour until a flow of 45,000 cfs is reached. Flows will be held essentially constant at 45,000 cfs for seven days (until April 2, 1996), with flow changes less than .:1:.1,000 cfs. Discharge will then be decreased to 8,000 cfs in the following manner: (1) Between flows of 45,000 cfs and 35,000 cfs, the down-ramping rate will be 1,500 cfs per hour; (2) Between flows of 35,000 cfs and 20,000 cfs, the down-ramping rate will be 1,000 cfs per hour; and (3) Between 20,000 cfs and 8,000 cfs, the down-ramping rate will be 500 cfs per hour. Discharge will be maintained at ..:t.8,OOO cfs for four days (through April 7, 1996). It is believed that this staggered down-ramp will more closely mimic the reduction of flows after a natural flood. The 8,000 cfs constant flows preceding and following the 45,000cfs release will permit aerial photography and on-the-ground evaluation of sedimentation patterns and impacts to river resources. Data collected during the test flow will demonstrate the extent to which planned flooding can be used as an ecosystem management tool. Interim flows will resume on or about April 8, 1996. b. Recreational Use The extensive recreational use of Glen Canyon National Recreation Area, which surrounds Lake Powell, is demonstrated by the visitation of 2,538,684 people during 1995. The NPS has concession-operated facilities at Wahweap, Dangling Rope, Halls Crossing, Hite, and Bullfrog Elasin on the reservoir and Lees Ferry, 16 miles below the dam on the Colorado River. The San Juan Marina, which was operated on Lake Powell by the Navajo Nation, is now closed due to a flood in 1989. From 1909 through 1961, an estimated total of 20,972 people visited Rainbow Bridge. When access to the bridge by water was made available by completion of the dam in 1963, visitation rapidly increased. In 1966,20.468 people visited Rainbow Bridge, almost as many people as had visited the site during the previous 53 years. In 1994,298,357 people (latest figure avail- able) visited Rainbow Bridge. l 39