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,-..'7... 0018 a Revised Supplemental Draft Environmental Assessment-Chapter 2-Alternatives Water Supply for Fish Passage Because of downstream senior water rights, a flow of at least 520 cfs is present in this reach ofthe river under all but the most severe drought conditions. The Service 'also has up to 37,650 acre-feet of storage water available from upstream reservoirs for endangered fish uses in drought years. About 80 cfs of Colorado River flow would be needed to operate the fish ladder. The fish passage notch would be designed to direct the first 80 cfs in the river to the fish passage channel. Additional flows would begin to spill over the rest of the dam at higher flows until the dam is completely submerged~ If built, the Jacobson Hydro No. Project would be required to discharge near the fish passage entrance to serve as an attraction flow. Without the Jacobson Hydro No. I Project, flows over the rock ramp would be directed towards the fish passage entrance to attract fish. Attraction flows would vary, dependant on flows in the river. Downstream Rock Fish Passage With Whitewater Recreation Features This alternative was developed through various meetings with representatives of the Western Association to Enjoy Rivers (WATER). The alternative would incorporate whitewater features into the Downstream Rock Fish Passage Alternative. The recreational community and possibly the Town of Palisade would secure the additional funding necessary to construct the recreational features concurrent with construction of the fish passage. Recreational features would include constructing a second notch in the Price-Stubb Diversion Dam for rafts and kayaks, and strategically placed boulders to create desired whitewater conditions on a 550 foot-long downstream rock ramp adjacent to the fish passage channel. Public access to use the whitewater features would be from the upstream Colorado River State Park-Island Acres and along Highway 6, or through easements obtained by the Town of Palisade from the CDOT (subject to CDOT approval). Design Thi~ alternative proposes placing fill and riprap material on the downstream face of the Price-Stubb Diversion Dam similar to the conceptual design shown in the Downstream Rock Fish Passage Alternative (see Figure 7). The fish passage would consist of 1) an approximate 550 foot-long downstream fish passage channel along river-left bank of the Colorado River with a 2.5 percent gradient, 2) an approximate 80 cfs low flow notch in the Price-Stubb Diversion Dam, 3) a second notch in the Price-Stubb Diversion Dam.to provide for rafts and kayak use, 4) an approximate 550 foot-long rock ramp structure with a 2.5 percent gradient with whitewater features, 5) a divider-berm between the fish passage channel and rock ramp, and 6) a rock barrier or sheet pile sill to assist in 16