Arkansas River Division 2 Design Report

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Design Report for Canon City Whitewater Kayak and Recreation Park in the Arkansas River • Pedestrian -560 * 5321.6 5321.6 -710 AU/12.1 5322.3 5321.2 5321.2 5321.2 Bridge -720 Railroad -740 AT/12 5321.3 5321.3 5321.3 5321.3 * RiverRestoration.org modeled cross section IX. Environmental Issues There are no known Section 7 endangered species issues in the proposed reach. The reach is managed by CDOW for cold water fisheries and the predominant species is Brown Trout. The substrate is cobble boulder bed and provides some spawning habitat within the reach. In this section of the Arkansas River Brown Trout are not reproduction limited(CDOW, Greg Policky, 2007). Project construction shall be timed outside of nearby spawning habitat closure periods as identified by the Colorado Division of Wildlife(personal communication Greg Policky CDOW, 2007). The hydraulic structures in the active channel shall be constructed during low water conditions between December 1, 2008 and March 31St, 2009. The CDOW recommended this construction period based on popular fishing prior to fall spawning season, as well as prior to fry hatch and popular fishing in early spring. Furthermore, this area is not reproduction limited and the • CDOW personell anticipate that with best management practices in place the impact on the channel bed would be local and no reach wide significant loss of eggs is anticipated during construction(CDOW, Greg Policky, 2007). Opportunities for bank improvements,riparian enhancements, removal of invasive Russian olives, and improved overhanging cover were recognized by the CDOW on a site visit November 1, 2007 (CDOW, Greg Policky). The Colorado Division of Wildlife suggested the use of tail out rocks to provide fish holding and resting areas for fish. Significant deposition of sand at the eddies, and fish passage were concerns expressed by the CDOW(Greg Policsky,2007). Scour and deposition of sand may occur due to changes in secondary currents and increases in eddy sizes; however, eddy velocities are expected to be sustained greater than 1 feet per second and prevent significant deposition. The hydraulic structures are designed to allow for fish passage with through channels at the perforated structures, and during high flows lower velocities occur at the sides of the structures. Any potential increase in flow velocities would be locally dissipated as a result of the hydraulic jumps that are created. Reach wide sediment transport and fluvial geomorphology would be unaffected by the project because of the armored cobble boulder bed. The current channel is stable and proposed modifications to local hydraulics IVE 10 of 16