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downstream from the USGS gaging station (approximately 1f2 mile below the <br />confluence) has previously been determined by the Division to not meet AVF criteria <br />based on insufficient availability of surface water to support flood irrigation and limited <br />extent of sub-irrigated vegetation. <br />The negative determination regarding flood irrigation capability due to insufficient water <br />availability would obviously apply to upper reaches as well. Field investigations were <br />conducted by the Division in July 1986, to evaluate the nature and extent of sub-irrigated <br />vegetation on Foidel Creek and its South Fork upstream from USGS gaging station <br />09243800. Observations indicated that the alluvial bodies are similar in terms of width <br />and type of sub-irrigated vegetation to alluvial bodies within the permit azea below the <br />gaging station. The portion of the South Fork between Spoil Pile 2 and Pond A could be <br />chazacterized as swampy, with sedges, rushes and willows the dominant vegetation. <br />Swampy conditions are not as prevalent below Pond A or upstream on [he main stem of <br />Foidel Creek, and the dominant sub-irrigated species are sedges, rushes and silver <br />sagebrush. In general, the sub-irrigated vegetation occurs in relatively narrow bands (less <br />than 200 feet wide) along [he flood plain, with a meandering incised channel which <br />would preclude farming operations. Due to the limited extent and nature of the <br />sub-irrigated vegetation, and insufficient water availability to support flood irrigation, the <br />alluvial bodies on Foidel Creek and its South Fork upstream from USGS gaging station <br />09243800 do not meet the alluvial valley floor criteria. <br />Map 6 of the original C-81-071 document indicates that two alluvial bodies of significant <br />extent occur on upper Middle Creek within Sections 26, 34 and 35, TSN, R86W, and <br />Section ]0, T4N, R86W. Little information is provided by the applicant regarding these <br />areas, however Map 15 of Twentymile Coal Company's Life-of--Mine Revision <br />Application for the Foidel Creek Mine indicates that a portion of the upper alluvial body <br />(approximately 35 acres) is flood irrigated farmland. Based on the available information, <br />it is the determination of the Division that the upper Middle Creek alluvial bodies <br />referenced above as delineated on Map 6 are alluvial valley floors based on geomorphic <br />criteria, flood irrigation capability (current and potential) and assumed capability to <br />support sub-irrigated vegetation. A portion (less than 300 acres) of the reclaimed Mine 1 <br />spoils is within the upper Middle Creek watershed and potentially could affect the quality <br />of water supplying the AVF. The remaining portions of Eckman Park and Mine 1 are <br />within the Foidel Creek watershed, and are not hydrologically connected to. the upper <br />Middle Creek AVF. <br />Potential impacts to identified alluvial valley floors have been reevaluated by the <br />Division to take into account the approved Life-of--Mine revision submitted by <br />Twentymile Coal Company (TCC) for the Foidel Creek Underground Mine, as well as <br />updated hydrologic projections for Eckman Park, Mine 1, Mine 2 and the proposed Little <br />Middle Creek Tract. The development in recent years of a spoil aquifer discharging as <br />saline springs and seeps along the toe of the regraded surface mine spoils represents a <br />potentially significant impact which was no[ originally predicted. Since the majority of <br />27 <br />