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0025iJ5 Some discussion also considered the concept that t100d t10ws counteracted the possible adverse impacts that t1uctuations had on beach erosion, thus rebuilding the deposits that would eventually slough back into the eddies, regardless of the nature of the powerplant operations, Some suggested that more frequent floods could allow higher levels of t1uctuations, Interpretation of Statute, the 1996 AOP Agreement, the GCDEIS ROD, and Risk With this evolving positive view towards spills, a desire for a test of the GCDEIS Beach Habitat Building Flow was expressed by the Transition Work Group beginning in 1994. This request for a purposeful powerplant bypass was strongly opposed by the Basin States, claiming a violation of the 1968 Colorado River Basin Project Act provision of avoiding anticipated spills, interpreted as powerplant bypasses, This opposition created an impasse that blocked such a test, Additional discussions between members of the Transition Work Group and the Basin States resulted in a proposal for a modification of the GCDEIS preferred alternative, that of moving Beach Habitat Building Flows (BHBF) from years oflow reservoir conditions (when spills would not be required for hydrologic reasons) to years of high reservoir conditions and high inflows, Thus a BHBF would occur in years when there was an expectation of having a hydrologically induced spill. Since the researchers had targeted the March-April timeframe as the preferred time for a BHBF, the water that would have been expected to spill in June or July would be pre-released earlier in the year to accomplish the intent of the BHBF. Some researchers had concerns about the magnitude of releases in temporally adjacent months of the BHBF, citing the potential for high powerpIant releases to negate the beach building gains made during the BHBF, Long term sediment balance continued to be a concern, However, the benefits ofreaching a compromise solution outweighed these possible negative impacts and this agreement was institutionalized in the 1996 Annual Operating Plan for the Colorado River, signed by the Secretary of the Interior in December 1995. The following March and April 1996, the requested test of the BHBF occurred with a release of 45,000 cfs for a period of 7 days, This flow included a powerplant bypass of about 15,000 cfs. Such a release was not required for hydrologic reasons, but was allowed by the Basin States as a one-time test as a result of the agreement contained in the 1996 AOP. Ih December 1996, the GCDEIS Record of Decision was signed by the Secretary of the Interior and included this modification of the preferred alternative. The BHBF negotiations did not include an explicit discussion of the hydrologic situation that should trigger a BHBF. Some recognition was given to the concept that this risk could be something less than the 50 percent level produced by using the most probable forecast from the National Weather Service as the inflow hydrology, but those discussions were left unresolved at the time of the signing of the GCDEIS ROD, At the April 1997 BHBF symposium, the issues ofBHBF frequency, high powerplant releases, and BHBF benefits were again raised, It is these issues of risk and frequency,that the TWG-s'pill subgroup now addresses. 3