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APPENDIX P
<br />McClave 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-yearflood 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 increased 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 iower 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; Washindton 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 LC5o 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 wafer 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 LC50 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 Pe_ ckarsky,
<br />2001; Markarian et al., 1994).
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<br />PR -02 10/12
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