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<br />001671 <br />Revised Supplemental Draft Environmental Assessment-Chapter 2-Alternatives <br /> <br />Downstream Rock Fish Passage <br /> <br />This alternative was developed in response to public comments on the 1999 Draft EA <br />with input from affected parties. The Downstream Rock Fish Passage Alternative would <br />. notch the Price-Stubb Diversion Dam and leave the Dam in place. A rock ramp fish <br />passage would be constructed on river left2 of the downstream face of the dam. This type <br />offish passage would not prevent construction of the Jacobson Hydro No.1 Project, <br />however, the proposed project would require additional modification and design. <br />Significant modifications include elimination of the 4-foot flashboards on the dam and <br />moving the hydroplant downstream or an extension of the hydroplant discharge to the <br />downstream entrance of the fish passage. <br /> <br />Similar rock fish passages were constructed in the San Juan River by the San Juan River <br />Basin Recovery Implementation Program to restore endangered fish passage. An "in- <br />river" rock fish passage was constructed in 2002 at tIie Hogback Diversion Dam on the <br />San Juan River in near Shiprock, New Mexico (Figure 4). An "out-of-channel" rock fish <br />passage with selective fish passage (fish trap) was constructed in 2003 at the Public <br />Service Company of New Mexico Diversion Dam on the San Juan River near Fruitland, <br />New Mexico (Figure 5). Fish passage use by Colorado pikeminnow and razorback <br />sucker has been documented at the Public Service Company of New Mexico fish passage. <br /> <br />Design <br /> <br />Conceptual designs (Figure 6) propose placing fill material on the downstream face of the <br />Price-Stubb Diversion Dam to create fish passage. The fish passage would consist of 1) <br />an approximate 30 foot-wide and 550 foot-long downstream fish passage channel along <br />river-left bank ofthe Colorado River with a 2.5 percent gradient, 2) an approximate 80 <br />cfs low flow notch in the Price-Stubb Diversion Dam, 3) the remaining 250-foot-width of <br />the dam would be stabilized, 4) a divider-berm constructed between the fish passage <br />channel and the riverbed and 5) and rock barrier or sheet pile barrier to assist in directing <br />fish to the passage entrance. In discussions with CDOT, a 20 foot offset of the fish <br />passage channel was established to allow for potential widening of Interstate 70. <br /> <br />This alternative would be constructed if a local governmental entity did not sponsor <br />white water recreation features as described in the Downstream Rock Fish Passage with <br />Whitewater Features alternative. Recreational interests design consultants have stated <br />that a 2.5 percent sloped rock ramp without additional features may be too steep for safe <br />boat passage, therefore if non-Recovery Program funds were not available, Reclamation <br />would stabilize the river channel and address public safety with signage aqd construct a <br />log boom across the fish passage entrance to prevent boaters from attempting to float <br />through the fish passage. <br /> <br />2 River left refers to the left side of the river as viewed when looking downstream. <br /> <br />12 <br />