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McClane Canyon Mine Expansion and Fruita Loadout Facility Biological Assessment <br />the rail bed. In addition, there would be 0.031 acre of rip -rap placed on the east bank of Reed <br />Wash extending from the ordinary high water mark (OHWM) to the concrete abutment <br />supporting the bridge on the east side. <br />There are approximately 40.53 acres of critical habitat that have been mapped within the 100 - <br />year floodplains of Reed Wash and Loma Drain combined, as mapped by the Federal <br />Emergency Management Agency FEMA (Mesa County, 2011). The project would physically <br />alter 0.124 acre (railroad bed and rip -rap) within the 100 -year floodplain in Reed Wash, about <br />0.3 percent of the mapped total. <br />Five rows of pilings that the support the rail bridge would be within the 100 -year floodplain <br />however, the spacing of pilings has been adjusted so that none would be located within the <br />OHWM of Reed Wash. Consequently, flows within the OHWM would not be affected by the <br />bridge and supporting piles. Evaluation of a 100 -year flood event was conducted with a <br />discharge rate of 1,861 cfs at the bridge site with and without the bridge present. The presence <br />of the bridge increased.the 100 -year flood surface water elevation by 0.61 feet over the surface <br />water elevation without the bridge. The maximum incre water elevation would allow 1.75 <br />feet separation between the water surface and bridge bottom. The analysis concluded that the <br />presence of the railroad bridge would not cause avulsion of the 100 -year floodplain or <br />inundation beyond Reed Wash. <br />Acoustic Impact. Driving pilings in water can physically injure fish from the impact of percussive <br />sound pressure (Popper et al., 2006). Effects to fish are dependent on numerous factors <br />including the size of fish, pile size and material, impact equipment, distance of fish from the <br />source, water depth, bottom material, bottom topography, currents or tidal flux, and river <br />sinuosity (Washington State Department of Transportation, 2008). The railroad bridge has been <br />designed so that pilings would not be placed within the OHWM of Reed Wash. Underwater <br />noise may be generated by driving piles on stream banks (dry piles) because some noise <br />propagates through ground and sediments (especially harder sediments such as rock and clay), <br />and may transfer to the water column somewhere else (known as sound flanking). Sound in the <br />water column would be at a lower level than at the source (Washington State Department of <br />Transportation, 2008) because most sound energy does not travel through water but through <br />the sediment. Fish present in Reed Wash would be expected to hear (sound transduced by the <br />swim bladder) noise produced by dry pile driving but sound levels would not result in injury <br />because the shock wave energy would be dissipated (Laughlin, 2006; Washington Department <br />of Transportation, 2008). <br />Hazardous Materials. Reed Wash and the 100 -year floodplain could be adversely affected if <br />petroleum products were accidentally discharged into surface waters and the floodplain. Such <br />materials are toxic to algae, invertebrates, and fish. Diesel fuel spills affect freshwater stream <br />macroinvertebrates over space (some distance downstream from the spill) and over time, for <br />more than one year after a spill (Lytle and Peckarsky, 2001). During 96 -hour tests of acute <br />toxicity, the LC for juvenile coho salmon exposed to diesel fuel ranged between 2,186 and <br />3,017 mg /L (World Health Organization, 1996). Water accommodated fractions (standardized <br />preparation of water systems with dissolved oil components for toxicity studies) prepared from <br />oils higher in aromatics (e.g. the middle distillates, including Fuel Oil No. 2, kerosene, and <br />diesel) are generally more toxic than those prepared from crude oils and gasoline (e.g. <br />Anderson et al., 1974; Rice et al., 1976; Markarian et al., 1994). Consequently, the LC for <br />crude oil would most likely be higher and less toxic than those values, above, for diesel fuel. <br />Impacts to aquatic habitats that primarily affect aquatic substrates — hence fish spawning, <br />incubating and rearing habitats — can remain for much longer periods (Lytle and Peckarsky, <br />2001; Markarian et al., 1994). <br />25 <br />