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additional detailed information on the characteristics of the alluvial body and the <br /> availability of sufficient water to support agricultural activities. Based on information <br /> contained in the report and information supplied to the Division by the Meeker Office of <br /> the Soil Conservation Service regarding regional flood irrigation practices, the Division <br /> has made a negative alluvial valley floor determination for those portions of Red Wash <br /> situated within the Deserado Mine permit area. <br /> As such, the findings of the Division regarding the AVF determination for Red Wash and <br /> its associated alluvium are as follows: <br /> Red Wash Alluvial Valley Floor Determination <br /> The Division has determined that Red Wash and its associated alluvium meets the <br /> geomorphic criteria, but not the irrigation requirements of an AVF, as outlined in OSM's <br /> "Alluvial Valley Floor Guidelines" established pursuant to the Surface Mining Control <br /> and Reclamation Act of 1977. <br /> Specifically,pursuant to Rule 2.06.8(3)(c), the Division finds that there is not sufficient <br /> water to support agricultural activities. The Division therefore concludes that Red Wash <br /> is not an Alluvial Valley Floor. <br /> Scullion Gulch <br /> Water Availability Criteria-Artificial Flood Irrigation <br /> As with Red Wash, flow events along Scullion Gulch were monitored using a crest stage <br /> gage. During the two year inventory period conducted by the permittee, only three runoff <br /> events were recorded, the highest event measuring 185 cfs. Again, however, crest-gage <br /> data has only limited application for AVF purposes. The mean annual yield estimations <br /> provided by the permittee are more applicable for identifying the amount of water that <br /> may be expected for Scullion Gulch. The permittee's estimations, derived using <br /> Grunsky's Formula, indicate that the potential average annual water yield from the <br /> Scullion Gulch watershed is 202 acre feet. This corresponds to approximately 0.34 inches <br /> of runoff. The amount of water available annually, as estimated through this method, <br /> indicates that Scullion Gulch warrants further consideration as a potential alluvial valley <br /> floor. <br /> Subirrigation <br /> As with Red Wash,the presence of subirrigation along Scullion Gulch was investigated by <br /> the permittee based on the type of vegetation present along the drainage. The permittee <br /> has identified a big sage brush - greasewood community along the entire length of <br /> unconsolidated alluvial deposits identified on Map 102, and concludes that water is <br /> available to the vegetation "on a limited and sporadic basis". The big sage <br /> brush-greasewood community, however, is more sparse compared to that community <br /> found along Red Wash, indicating that the availability of subsurface water is much more <br /> xxxviii <br />