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<br />upon ~h. daily fluc~ua~ion allowed. Aacending ra~ea of 2,500 cfa/hour cloaely <br />approxima~e ~h. Scien~ific recommenda~ion when considering a~~enuation. <br />Descending ramp rates are more critical in protecting the resources impacted <br />by fluc~uation.. Based on the reduction in daily fluctuations and attenuation <br />effects, 1,500 cfs/hour appears to be a reasonable descending ramp rate. <br /> <br />R.co_.Dda~ioD. <br /> <br />Based on ~he la~es~ information available and the preceding evaluations, <br />Reclama~ion proposes the following interim operating criteria: <br /> <br />Parameter <br />Maximum Flow <br />Minimum Flow <br /> <br />Ramp Rates <br />Ascending <br />De.cending <br /> <br />20,000 cfs' <br />5,000 cfs - night~ime <br />8,000 cfs - 7 a.m. to 7 p.m. <br /> <br />8,000 cfs/4 hours not to exceed 2,500 cfs/hour <br />1,500 cfs/hour <br /> <br />Daily Fluctuations 5,000/8,000 cfs' <br /> <br />Research flows are scheduled to end on July 31, 1991, and interim operating <br />criteria are to be implemented by November 1, 1991. During that 90-day <br />period, appropriate NEPA compliance will be completed. With high visibility <br />and interest in protecting resources in Glen and Grand Canyons, testing of <br />the proposed interim operating criteria prior to their implementation is <br />de9irable. <br /> <br />The test will be conducted as follows: <br /> <br />(1) The above proposed interim operating criteria for Glen Canyon <br />Dam will be implemented on a test basis on August 1, 1991. It is recognized <br />that a transition period may be necessary in recognition of power contracts, <br />replacement energy, and other arrangements which are associated with modified <br />operations. This transition period will be as short as possible. <br /> <br />(2) <br />criteria. <br />protective <br />considered <br /> <br />A monitoring program will evaluate performance of the proposed <br />The monitoring will focus on identifying residual problems. Local <br />measures, in addition to modification of operations, will be <br />to reduce residual impacts during interim flows as appropriate. <br /> <br />(3) Exception criteria used during research flows will be extended for <br />the test period beginning August 1, 1991. By August 15 it is anticipated that <br />Reclamation and Western, with input from the Department of Interior, will <br />draft and agree to revised exception criteria to be put in place at that time. <br />This will also provide a test of the exception criteria. <br /> <br />By November 1, 1991, we anticipate the completion of any necessary <br />NEPA compliance which will allow for final implementation of interim operating <br />cri~eria. <br /> <br />I To be evaluated and potentially increased as necessary for years when <br />delivery to ~he Lower Basin exceeds 8.23 maf. <br /> <br />, Daily fluctuation limit of 5,000 cfs for months with release volumes <br />les. than 600,000 af, 6,000 cfa for monthly release volumes of 600,000 ~o <br />800,000 af and 8,000 cfs for monthly volumes over 800,000 af. <br /> <br />4 <br /> <br />, <br />..~ <br />