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The reclamation procedure should also restore the essential hydrologic <br />function of subirrigation. Quantity and quality of water is largely <br />regulated by the Colorado River. Any quality changes resulting from <br />the surface operations will be of short duration due to the close <br />proximity of the Colorado River and the extensive underflow associated <br />with this relatively large surface water flow system. In addition, if <br />aground water problem is detected by the monitoring program, <br />mitigation measures will be undertaken prior to reclamation of the site. <br />Powderhorn Coal Company will monitor shallow ground water levels at 3 <br />piezometers and at one well near the unit train loadout facility. <br />Water levels will be taken monthly, and water quality samples will be <br />collected on a quarterly basis from the well. The well is located near <br />the coal storage pile to monitor the effects of leaching of the coal <br />storage pile. <br />Rapid/Cottonwood Creek Area <br />four distinct areas were examined for identification of alluvial valley floors <br />in the vicinity of Rapid Creek and Cottonwood Creek. these areas were <br />Cottonwood Creek, Rapid Creek, minor ephemeral streams and the Colorado River <br />adjacent to the Rapid Creek and Cottonwood Creeks watersheds. None of these <br />areas are covered by the "grandfathering" exemption. <br />The Cottonwood Lreek valley does not meet the geomorphic characteristics of an <br />alluvial valley floor. The valley is narrow, and any fill material does not <br />meet the AVF size criteria. <br />Valley fill deposits located along Rapid Creek have been interpreted as a <br />mudflow fan deposit which has been modified and reworked by Rapid Creek to <br />form three terrace levels. The upper terraces (T2 and T3) are irrigated or <br />have been irrigated with the flow from Rapid Creek. The lowest terrace (Tl) <br />is narrow and has not been flood irrigated. The T1 terrace includes a narrow <br />land of subirrigation along the creek, but the species present are not <br />agriculturally useful. subirrigated species located on the T2 terrace are <br />deep rooted and do not indicate the general availability of ground water to <br />agriculturally useful species. The T3 terrace does not have vegetation <br />indicating subirrigation. <br />Several minor ephemeral streams also drain the permit area. The stream <br />valleys are narrow, steep, and contain very little alluvium. None of these <br />valleys contain deposits meeting the AVF size criteria. <br />Areas along the Colorado River have been identified as terrace landforms with <br />existing flood irrigation. The lowest terrace is marginally subirrigated, but <br />the upper terraces are not subirrigated. <br />Based on the above information, two areas of alluvial valley floors can be <br />identified. The two upper terraces (T2 and T3) have been identified as <br />unconsolidated streamlaid deposits, and have sufficient waters to support <br />flood irrigated agricultural activities. (Except, two of the areas designated <br />-23- <br />