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., 'I rl Interim Flow Period , :1 Interim Flows, instituted until a Record of Decision is reached on the EIS, were originally set at conservative levels on the theory that high fluctuating flows were the causative agent for most if not all perceived problems in the canyon. After several months of studying the new Interim Flows, scientists concluded otherwise. * Small up ramping rates as required under Interim Flows were found to be unnecessary to prevent sandbar erosion. Scientists found no evidence that raising the maximum upramp of 2,500 cfs/hour under Interim Flows to 4,000 cfs/hour would be detrimental to downstream natural or cultural resources. This observation produced a recommendation after consultation that the maximum upramp of 2,500 cfs/hour under Interim Flows could be raised to 4,000 cfs/hour. We conclude that doing so would not result in harm to beaches, riparian habitat, fish or other downstream resources. , < ': , :~ :~ * Scientists also found no evidence that infrequent raising of the maximum release from 20,000 cfs to 25,000 cfs would be detrimental to downstream natural or cultural resources. This observation produced a recommendation from research scientists that the maximum release in the interim be raised to 25,000 cfs.' We conclude that doing so would not harm beaches, riparian habitat, fish or other downstream resources and would likely preserve riparian areas currently desiccated as a result of the more restrictive maximum release. , .. -: ::1 r " * Some biologists fear Interim Flows and eventually the Preferred Alternative with their lowered river level and more stable flows will accelerate the decline in Old High Water Zone vegetation and species in the upper portion of the New High Water Zone. In fact, decreased water levels in the lower canyon has resulted in many riparian plant species and individuals dying, beginning at the upper most elevations. * High elevation wet and dry marshes previously maintained by periodic wetting from fluctuating flows, have begun to diminish in size and number. This is due to more uniform flows which leaves some parts always exposed and dried and some parts always flooded. ~;I " ;~ .'. ", ~.~ ... " ~. ;-,.- ~ r " ,. ~ < ...1 ";...: ~ ,. * The reduction in fluctuations with Interim Flows has lessened the sloughing of algae in the upper river and this has caused a significant reduction in algal drift downstream. * Large numbers of young Humpback chub have been found in the river and the Little Colorado River but these large numbers were attributed to favorable spawning and rearing conditions in the LCR rather than due to Interim Flows. The EIS should , ,;. 5