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Beaches deposited during high, steady flows are rapidly eroded when exposed to either fluctuating or steady, lower flows, but the rate of erosion diminishes and equilibrium is reached after several years of similar releases. However, the stable beach area that develops in response to fluctuating flows is smaller than that developed during steady flows of the same annual volume, and could be substantially smaller depending upon release patterns. I I I I I I I I I I I I I I I I I I I Hodified operations Could Protect Or Enhance Host Resources The GCES found that changes in operation of the dam to reduce fluctuations and avoid flood releases could reduce the resource losses occurring under current operations and, in some cases, even improve the status of the resources. Five modified patterns of op- erations were designed, each to address one or more critical resources. These patterns have been con- strained only by the need to release a minimum of 8.23 million acre feet (maf) per year and maintain minimum flows of 1,000 cfs in winter and 3,000 cfs in summer, and stay within the designated powerplant capacity of 31,500 cfs. These modifications only approximate ideal release patterns for individual downstream resources. They illustrate the types of changes that would protect or enhance resources, but do not represent the full range of possible options. These modifications should not be considered as fullY develo~ed or recommended oDerational schemes. operational Changes Are unlikely To Help Humpback ChUb In 1978, the u.s. Fish and wildlife Service concluded that the continued existence of the endangered humpback chub in Grand Canyon was jeopardized by dam operations. The cold water released from the dam has made the mainstem Colorado River unsuitable habitat 'for rearing chub. Rearing is now restricted to the mouth of the