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e e Federal Register/Vol. 70, No. 59/Tuesday, March 29, 2005/Notices 15881 has jeopardized the interests of the Upper Basin and put at risk the future generation of hydroelectric power at Glen Canyon Dam. Response: The severity of the drought over the past five years in combination with the objective to maintain a minimum release of 8.23 million acre- feet has caused a significant drawdown of Lake Powell. The minimum release objective contained in the Operating Criteria results in Lake Powell storage decreasing during periods of drought. From 1988 through 1992, there was a five-year drought in the Colorado River Basin and the water surface elevation of Lake Powell decreased by 89 feet. The drought of the past five years (2000- 2004) is more severe than the drought that occurred from 1988 to 1992. Records show the current drought to be the most severe five-year drought in the Colorado River Basin in over 100 years of recordkeeping. Because of this, Lake Powell has experienced a significant reduction in storage. Elevation 3,490 feet at Lake Powell has been identified as the minimum level at which hydropower can be generated at Lake Powell. The river bypass tubes at Glen Canyon Dam can release water as low as elevation 3,370 feet, but no hydropower can be generated by the release of water through the river bypass tubes. Elevation 3,370 feet is the lowest elevation at which water can be released from Lake Powell. Between elevations 3,490 feet and 3,370 feet, there is four million acre-feet of storage. The Operating Criteria do not reference these elevations at Lake Powell. Previous river simulation modeling of the Colorado River system performed by Reclamation showed no occurrences of Lake Powell reaching 3,490 feet in the next 50 years when subject to the most severe droughts of the 20th century. However, since the current five-year drought is worse than any of the 20th century droughts, there is now some risk that Lake Powell could reach minimum power pool (elevation 3,490 feet) under a scenario of continued drought in combination with the continuation of the minimum release objective from Lake Powell. The Department will continue to address the issue of low reservoir storage at Lake Powell in the Annual Operating Plan consultation process. In addition, see response to Comments No. 34 and 38. Comment No. 4o-(Letter No. 19): Over the past 10 years, the Upper Basin has delivered more than 100 million acre-feet of water to the Lower Basin, which now in combination with drought conditions has prejudiced the interests of the Upper Basin. Response: During the past 10-year period (water years 1995-2004), over 100 million acre-feet has flowed past Lee Ferry. The majority of this flow occurred during the five-year period of 1995 through 1999 which was a period with above average flow on the Colorado River. In July 1999, Lake Powell storage was 97 percent of capacity. During the five-year period of 1995 to 1999, 59.5 million acre-feet flowed past Lee Ferry, with reservoirs throughout the Upper Colorado River Basin, including Lake Powell, releasing excess water because they were full. Release of this water from Lake Powell was necessary because of the physical storage limitation of Lake Powell and dam safety considerations. During the past five years, the objective in the operation of Lake Powell has been to release 8.23 million acre-feet per year, consistent with the Operating Criteria. It should also be noted that during the late 1990s, flood control releases were taking place from Lake Mead in the Lower Basin resulting in a significant volume of water, approximately 5 million acre- feet, being released from Lake Mead in excess of Lower Basin demands. In addition, see response to Comment No. 34. Comment No. 41-(Letter No. 19): The existing Operating Criteria need clarification that the minimal objective release of 8.23 million acre-feet stated in the Operating Criteria is an "operating target" which is subject to revision in the Annual Operating Plan process. Response: See response to Comment No. 34. Comment No. 42-(Letter No. 19): The Friends of Lake Powell strongly endorse the Annual Operating Plan process. Furthermore, we believe that operation of the Colorado River reservoirs can be optimized with each Basin sharing more equitably in the burden of drought. This would be best accomplished by maintaining, as equally as practicable, the active water stored in Lake Powell and Lake Mead (for so long as Upper Basin 10-year water delivery obligations are satisfied). Response: Under the Operating Criteria, Lake Powell storage drops below Lake Mead storage during periods of drought. When there is a return to average or above average inflow, Lake Powell storage recovers faster than storage recovers in Lake Mead. The 602(a) Storage requirement allows water storage in Lake Powell to be greater than water storage in Lake Mead in the period following a drought. Maintaining storage equal in Lake Powell and Lake Mead as an operating strategy would be counter to the 602(a) Storage requirement and could put the Upper Basin at risk of not having enough water in storage for future droughts. The Department will continue to address low reservoir storage caused by drought in the Annual Operating Plan consultation process. In addition. see response to Comments No. 34 and 38. Comment No. 43-(Letter No. 20): The Operating Criteria of Glen Canyon Dam need to be revisited. When all needs are considered, it would be better to treat Lakes Mead and Powell more similarly, or better yet, to apply your normal system Operating Criteria to the operation of Glen Canyon Dam. Response: See response to Comments No. 34, 38, and 42. Comment No. 44-(Letter No. 21): The technical changes proposed in the current Operating Criteria review seem to make sense in order to keep the document current with regards to updated legislation and rules. Response: Comment noted. Comment No. 45-(Letter No. 21): With the current drought and the ongoing discussions by the seven Colorado River Basin States as to how to cope with low storage levels in the system, it would be appropriate for this review of the Operating Criteria to serve as the current review for at least the next five years. During this time, the seven Basin States will be working together to provide additional guidelines dealing with shortages. Similar to the Interim Surplus Guidelines process, if and when shortage guidelines are agreed to and given time to develop operational experience, it would be appropriate to again review the Operating Criteria. Response: See response to Comment No. 35. Comment No. 46-(Letter No. 22): Page Electric Utility strongly believes that the water level of Lake Powell should be maintained at or above elevation 3,490 feet to maintain the minimum power pool. Response: See response to Comments No. 34 and 39. Comment No. 47-(Letter No. 23): We have no objections to the proposed removal of obsolete provisions in the Operating Criteria. Response: Comment noted. Comment No. 48--(Letter No. 23): An amount less than the minimum release objective may be released from Lake Powell, if the states of the Upper Division are in compliance with Article III(d) of the Colorado River Compact, in order to avoid impairment or potential impairment of the beneficial consumptive use of water in any Upper Division State. Response: See response to Comment No. 34.