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Rapid/Cottonwood Creek Area <br />Four distinct areas were examined for identification of alluvial valley floors in the vicinity of Rapid <br />Creek and Cottonwood Creek. These areas were Cottonwood Creek, Rapid Creek, minor ephemeral <br />streams and the Colorado River adjacent to the Rapid Creek and Cottonwood Creeks watersheds. <br />None of these areas are covered by the "grandfathering" exemption. <br />The Cottonwood Creek valley does not meet the geomorphic characteristics of an alluvial valley floor. <br />The valley is narrow, and any fill material does not meet the AVF size criteria. <br />Valley fill deposits located along Rapid Creek have been interpreted as a mudflow fan deposit which <br />has been modified and reworked by Rapid Creek to form three terrace levels. The upper terraces (T2 <br />and T3) are irrigated or have been irrigated with the flow from Rapid Creek. The lowest terrace (T1) <br />is narrow and has not been flood irrigated. The T1 terrace includes a narrow band of subirrigation <br />along the creek, but the species present are not agriculturally useful. Subirrigated species located on <br />the T2 terrace are deep rooted and do not indicate the general availability of groundwater to <br />agriculturally useful species. The T3 terrace does not have vegetation indicating subirrigation. <br />Several minor ephemeral streams also drain the permit area. The stream valleys are narrow, steep, and <br />contain very little alluvium. None of these valleys contain deposits meeting the AVF size criteria. <br />Areas along the Colorado River have been identified as terrace landforms with existing flood <br />irrigation. The lowest terrace is marginally subirrigated, but the upper terraces are not subirrigated. <br />Based on the above information, two areas of alluvial valley floors can be identified. The two upper <br />terraces (T2 and T3) have been identified as unconsolidated streamlaid deposits, and have sufficient <br />waters to support flood irrigated agricultural activities. (Except, two of the areas designated on Map 1 <br />as have been disturbed by previous unrelated mining activities and by construction of water treatment <br />facilities and should not be identified as alluvial valley floors.) The areas designated as CRT <br />(Colorado River Terrace), as well as the lower terraces and floodplain along the Colorado River, are <br />determined to be alluvial valley floors. The areas identified as CRT consists of unconsolidated <br />streamlaid deposits that are currently flood irrigated. The lower terraces and floodplain are flood <br />irrigated in several areas (Map 2), and may be subirrigated in places. <br />Significance to Agriculture <br />Since no agricultural information has been provided from any of the areas designated as alluvial valley <br />floors, all the areas will be assumed to be agriculturally significant, and all three alluvial valley floor <br />fmdings will be made. <br />Rapid Creek Alluvial Valley Floor - Findings <br />1. The proposed surface coal mining operations would not interrupt, discontinue, or preclude <br />farming on an alluvial valley floor (4.24.3(1)). <br />The area designated as alluvial valley floor lies outside of the permit area, downstream from the <br />proposed operations. As a result, there would be no surface disturbance within the AVF, and the <br />area would not be undermined <br />Permit Revision No. 5 55 July 10, 2012 <br />