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<br />, <br /> <br />4 <br /> <br />. safety become significant. options for release patterns become fe\ver. In general. monthly <br />release volumes are kept above 550.000 AF and below [,200.000 AF when possible. Mid- <br />winter and mid-summer releases are often greater than other months due to higher linn power <br />demands. In years of high snowpack. monthly releases are increased beginning in January to <br />make space for the expected spring runoff. <br /> <br />Under existing practice. daily releases can range significantly within power plant capacity (max <br />33.200 cfs; min 5.000 cfs) in accordance with the limits established by the recently signed <br />Operating Criteria for Glen Canyon Dam. Daily releases greater than 33,200 cfs bypass the <br />generators and require use of four jet tubes which have a combined capacity rating of \5.000 cfs. <br />Full generator and jet tube capacity is about 48,000 cfs and is viewed as the normal maximum <br />release capacity of the dam, due to considerations for spillway protection. Passing greater than <br />48,000 cfs through the dam requires use of the spillways, which can lead to degradation of the <br />concrete spillway lining. <br /> <br />What is the timeframe for development of each year's AOP? <br /> <br />. <br /> <br />The AOP should be issued by October 1 of each year, and is signed by the Secretary of the <br />Interior. It contains projected operational information for the coming water year (October <br />through September) for all the mainstream reservoirs in the Colorado River Basin. Reclamation <br />sponsors a "work group" which provides an opportunity for public discussion. Reclamation then <br />uses comments received at these meetings to recommend decisions for the SecretJ[\" s issuance. <br />- . <br />The group usually meets 4 or 5 times, beginning between January and April of the previous <br />water year. Often. the topics for discussion also include policy-related issues such as surplus and <br />shortage detenninations, risks of spills, and banking and leasing. This group typically has not <br />addressed powerplant operations at Glen Canyon. <br /> <br />What is the relationship between the 5-year review of the Operating Criteria and <br />the AOP? How does the '68Act apply to AOP-type issues? <br /> <br />In addition to the preparation of an AOP, the 1968 Act required a periodic review of the <br />Operating Criteria. The review of the Criteria is sponsored by the Secretary at least every 5 <br />years to determine "if as the result of actual operating experience or unforeseen circumstances" <br />the Criteria should be modified. The Criteria has thus far been kept purposely broad to allow the <br />resolution of yearly operating issues within the context of the AOP. Reviews have occurred in <br />1975, 1980, 1985, and 1990 after the establishment of the original Criteria in 1970. The current <br />1995 review is scheduled to be completed in the fall of 1997. <br /> <br />. <br /> <br />The AOP is prepared using the general guidance contained in the Operating Criteria. With <br />respect to Glen Canyon Dam operation, the Criteria basically contains a restatement of the 1968 <br />Act provisions. The releases for the coming water year are based on a most probable forecast (in <br /> <br />Reclamation Discussion Paper -- Working Draft -- 3/24/97 version <br />