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CHAPTERFOUR Responses to Pubtic and Agency commetns <br />Letter and • <br />Comment No. Response <br />Flow in Parachute Creek may also be slightly depleted by the withdrawal <br />from the alluvial wells. The average daily flow in Parachute Creek at <br />Parachute (L1SGS station 09093500), which is downstream of the Unocal <br />site, for the period of record from 1975 to 1982 is 31.74 cf ~. The 1.6 cfs <br />depletion represents approximately 5 percent of the flow. 'I1us reduction in <br />flow is not considered significant enough to adversely effect the riparian <br />habitat or aquatic habitat of Parachute Creek. <br />The discussion on page 4-13 of the Draft EIS has been reviised to refer the <br />reader to page 4-67 where the discussion of potential effects to surface <br />water and aquatic habitat are discussed. The cumulative elTects discussion <br />on page 5-4 of the Draft EIS is referring to groundwater withdrawal in the <br />Piceance Basin. The Yankee Gulch Project does not propose to withdraw <br />any groundwater in the Piceance Creek watershed, and the water <br />withdrawal in the Parachute Creek watershed is considered surface water <br />depletions, as discussed above. The discussion on page 5-4 of the Draft <br />EIS has been expanded to evaluate the potential cumulative effects of the <br />identified projects from groundwater withdrawal. <br />F-2.26 The statement is a qualitative assessment based on consideration of several <br />factors. The engineering design, material specifications, and construction <br />practices for the pipeline are included in the Plan of Development <br />(Appendix E), and all would meet or exceed applicable Department of <br />Transportation (DOT) standards and industry standards. The pipeline <br />would be located along an existing corridor throughout most of its length, <br />where previous pipelines have been successfully installed and operated. <br />The area is in a region of low seismicity. The pipeline insulation is likely <br />to provide some additional protection from third-party damage (e.g., a <br />backhoe operated by others) and rock gouging. It is also expected to <br />provide some protection from outside corrosion and minor soil stresses. <br />There is always a potential for a breach; however, the relative risk of <br />breach may be considered low or unlikely in light of these factors. The <br />potential for significant impacts if a breach did occur aze discussed in <br />response to Comment MII-2.1. <br />F-2.27 A Pipeline Plan of Development (Plan) has been included in the Final EIS <br />(Appendix E). A Pipeline Spill Contingency Plan is described in <br />Attachment 7 of the Plan. Two spill scenarios aze discuss~:d in the <br />Contingency Plan; one would involve a suspected leak, thy; other a pipeline <br />breach or rupture. Operating conditions of the pipeline would be <br />monitored and deviations from the normal conditions would alert the <br />operator of a possible problem. The pipeline corridor would be visually <br />monitored 26 times a yeaz via aerial flyovers, with the time between <br />4-10 <br />