2007-04-05_GENERAL DOCUMENTS - M1977493 (2)

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Climax Mine Arkansas River Restoration Project downstream flow of the Arkansas through the existing brook trout fishery is not interrupted. Thus, by controlling the distribution of flow between the channel and pipeline through 2009, our design will provide the opportunity to establish vegetation and bank stability. 2.2.2 Reestablishment of a Viable Trout Fishery Upon completion of the new channel alignment, construction of the channel, and placement of physical habitat, it will be possible to reintroduce a viable trout fishery. The current resident salmonids in the East Fork of the Arkansas River are brook trout. Brook trout are not native to Colorado, but are commonly found in high-elevation streams and lakes throughout the State. Once water is introduced to the new channel, brook trout should rapidly colonize the new habitat. Movement of all life stages of trout in Colorado is common and occurs during seasonal spawning migrations or when trout are seeking better habitat or feeding conditions. All of these factors will be in play as brook trout occupy vacant habitat in the newly constructed stream channel. This will occur naturally and will not involve any restocking efforts on the part of Climax or the Colorado Division of Wildlife (CDOW). This is essentially a no action alternative for populating the new stream channel with trout. 2.2.3 Investigation and Design Methodology The Habitat Team used standard hydrologic and hydraulic analyses along with selected components of the Rosgen classification methodology to design the relocation and restoration of the 2,000-ft segment of the East Fork of the Upper Arkansas River. This project offers a unique challenge. Our team will relocate and reconstruct a new reach of stream to replace the reach that was covered with waste rock and rerouted through a concrete culvert. The geologic stability controls, gradients, meander characteristics and location of the reconstructed stream will be significantly different from the natural conditions found prior to disturbance. It is extremely important to recognize this difference, since many widely used approaches, such as the Rosgen classification system, focus on restoration of degraded streams, and not on the relocation and reconstruction of a new stream channel. The Habitat Team cautiously used the Rosgen classification systems to establish some of the baseline conditions on which to base our initial restoration planning. The sole use of a cookbook- type methodology, like the Rosgen approach, for engineering design or for predicting river behavior is not justified because the approach does not provide cause and effect solutions. However, the Habitat Team does believe that selected applications within the Rosgen approach are valid when coupled with other sound engineering design, and we incorporated that philosophy into our channel relocation and restoration design. The Rosgen classification system is comprised of five levels: geomorphic characterization (I), morphological description (II), observation of stream condition (III), measurements/observations of channel processes (IV), and fluvial geomorphology/engineering (V). The Habitat Team used selected components of the first two levels of the Rosgen classification system to help establish some of the baseline conditions, and couple this with a physically-based, deterministic approach that relies on quantifying the driving and resisting forces that control active processes, be they hydraulic, hydrologic or geotechnical. During our initial assessment work for many of our projects we use aerial photographs, digital elevation models and on-site observation to determine Rosgen Level I classifications for selected stream reference reaches. We use Rosgen geomorphic assessment and classification and a thorough understanding of the science of fluvial geomorphology to describe the behavior of the stream system, diagnose potential problems and develop solutions. We then use natural channel design procedures to collect reference reach data for each project. These data form the basis for creating stable, functional stream channels. Finally, we use hydrologic and hydraulic modeling Habitat Team March 28, 2007