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Final Report 1-12 Flow recommendations in the 1992 Biological Opinion for spring, summer, autumn, and winter (element 1 of the reasonable and prudent alternative) were based on the best available information and professional judgment of researchers who had collected and analyzed much of the data. The recommended flows were intended to restore the natural hydro graph to the extent possible and to provide a flow regime that would allow for enhancement and recovery of endangered and other native fishes in the Green River from the confluence of the Green and Yampa Rivers to Lake Powell. Because of data limitations and the location of areas believed to be crucial for protection of the endangered fishes, the Biological Opinion only recommended seasonal target flows for the Green River at the USGS gage near Jensen, Utah (located 157 km downstream from the dam). The seasonal flow and summer temperature recommendations are summarized below; the Biological Opinion provides additional details. Spring.-Timing and duration of spring releases from Flaming Gorge Dam are to be patterned after the spring flows of the Yampa River. Water releases from Flaming Gorge Dam are to begin increasing at a rate of no more than about 11.3 m3/s per day between 1 April and 15 May until a peak release of approximately 113-133 m3/s is attained. Peak releases are to be maintained for 1-6 weeks beginning between 15 May and 1 June, and the timings of these releases are to coincide with peak spring runoff in the Yampa River so that a target peak flow of 368-509 m3/s is attained at the USGS gage near Jensen, Utah. The duration of peak releases is to depend on the hydrological and meteorological conditions for a given year, with a longer release period to be used during high water years. The descending arm of the hydro graph is to be synchronized with the conclusion of spring runoff conditions in the Yampa River, and changes in releases from Flaming Gorge Dam are to be limited to no more than 11.3 m3/s per day during this period. During average water years, the entire spring peak is to occur over 6 to 8 weeks. If it becomes necessary to bypass water from the dam to alleviate storage problems, then the bypass should occur during or before the Yampa River spring peak. . September 2000 Power-plant capacity releases - Reservoir releases through the power plant that generate electricity. Power-plant releases from Flaming Gorge Dam typically range from 23 to 130 m3/s. Bypass tubes - Flaming Gorge Dam has two steel-lined tubes with a combined capability of releasing up to 113 m3/s of water. Water released through the bypass tubes does not produce electric power. Spillway - A gated overflow structure that can release up to 793 m3/s of water through a spillway tunnel. Water released through the spillway does not produce electric power. Penstocks - 3-m diameter tubes that carry water from the reservoir to the turbines at the base of the dam. A selective withdrawal structure was added to Flaming Gorge Dam's penstocks in 1978 so that water could be withdrawn from selected depths in the reservoir, thereby allowing some control over the temperature of the water released from the dam. Summer.-Water releases from Flaming Gorge Dam should decrease following the spring peak until a flow of31-51 m3/s is attained at the Jensen gage (actual flow within the recommended range is to be based on hydrologic conditions and Reclamation needs). Fluctuations in flow at the Jensen gage are to be limited to no more than 25% .