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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 />S'ubirrigation <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 />39 <br />