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suffocation. Water freely percolates through the gravel in some ponds where complete draining would be impossible. In these ponds, the remaining water treated with rotenone to kill nonnative fishes. Other ponds may be treated with rotenone without draining if water recharge occurs quickly or if it would be logistically impractical to get the large pumps to the site. All chemical treatments will be made using the Colorado Division of Wildlife Chemical Application Operating Procedure as standard protocol. Rotenone would be applied at a concentration of 3 milligrams per liter, mg/1 (parts per million, ppm) following the label directions with this registered piscicide. Fish absorb the chemical through the gills and are killed by the interruption of respiration within the body cells (Lindahl and Oberg 1961). Each crew would be supervised by a person who has been certified by the -- State of Colorado to apply chemicals. Rotenone has been found to be safe to humans when applied by certified applicators following label instructions -__ (Sousa et al. 1987). Rotenone is extremely toxic to many species of invertebrates and fish (Bradbury 1986). However, the toxicity of rotenone varies among various species of fishes so the concentration of 3 mg/1 Fppm) will be used to effectively kill black bullheads that are among the most resistant fish species (Marking and Bills 1976). Zooplankton communities are drastically reduced following rotenone treatments -- cladocerans and copepods are very sensitive while rotifers are most tolerant (Kiser et al. 1963). Generally, immediate reductions in numbers of benthic organisms ranged from 0 to 70% with a mean of 25% in freshwater treatments (Bradbury 1986). Zooplankton and benthic communities, however, recover quickly with no change in the original species composition -- zooplankton completely recover in 2 to 12 weeks and benthic communities generally recover within 2 months following treatment with rotenone (Bradbury 1986). Phytoplankton, rooted aquatic plants, and terrestrial plants are unaffected by rotenone treatments at concentrations used to kill fish (Bonn and Holbert 1961). Rotenone is relatively nontoxic to birds (Bradbury 1986) and mammals (Marking 1988), primarily because of the mode of entry and oxidizing enzyme systems in these two groups of animals (Fukami et al. 1969, 1970). Generally, the natural detoxification of rotenone is rapid and adequate in lakes, ponds, and reservoirs where the chemical will detoxify naturally within 2 days to 2 weeks in late summer and early fall, depending upon water temperature, sunlight penetration, and alkalinity of the water (Bradbury 1986). Detoxification is inhibited by turbidity and deep water because of decreased light penetration. Where chemically induced detoxification is necessary in cases such as percolation into streams, potassium permanganate is usually added in an amount equal to the rotenone concentration plus the permanganate demand of the water (Davies and Shelton 1983). No Impacts Anticipated on Vegetation or Historic/Cultural Resources. No impacts to vegetation or historic and cultural resources would result from actions taken in this alternative. The following environmental impacts are expected under this alternative: 16