2022-11-07_REVISION - C1981041 (2)

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been flood irrigated. The T1 terrace includes a narrow band of subirrigation along the creek, but the species present are not agriculturally useful. Subirrigated species located on the T2 terrace are deep rooted and do not indicate the general availability of groundwater to agriculturally useful species. The T3 terrace does not have vegetation indicating subirrigation. Several minor ephemeral streams also drain the permit area. The stream valleys are narrow, steep, and contain very little alluvium. None of these valleys contain deposits meeting the AVF size criteria. Areas along the Colorado River have been identified as terrace landforms with existing flood irrigation. The lowest terrace is marginally subirrigated, but the upper terraces are not subirrigated. Based on the above information, two areas of alluvial valley floors can be identified. The two upper terraces (T2 and T3) have been identified as unconsolidated streamlaid deposits, and have sufficient waters to support flood irrigated agricultural activities. (Except,two of the areas designated on Map 1 as have been disturbed by previous unrelated mining activities and by construction of water treatment facilities and should not be identified as alluvial valley floors.) The areas designated as CRT (Colorado River Terrace), as well as the lower terraces and floodplain along the Colorado River, are determined to be alluvial valley floors. The areas identified as CRT consists of unconsolidated streamlaid deposits that are currently flood irrigated. The lower terraces and floodplain are flood irrigated in several areas (Map 2), and may be subirrigated in places. Significance to Agriculture Since no agricultural information has been provided from any of the areas designated as alluvial valley floors, all the areas will be assumed to be agriculturally significant, and all three alluvial valley floor findings will be made. Rapid Creek Alluvial Valley Floor- Findings 1. The proposed surface coal mining operations would not interrupt, discontinue, or preclude farming on an alluvial valley floor(4.24.3(1)). The area designated as alluvial valley floor lies outside of the permit area,downstream from the proposed operations. As a result, there would be no surface disturbance within the AVF, and the area would not be undermined. 2. The proposed surface coal mining operations would not materially damage the quantity and quality of water in surface and groundwater systems that supply these alluvial valley floors or portions of alluvial valley floors (4.24.3(3)). The Rapid Creek alluvial valley floor receives the water supply from the Rapid 65