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southwestern and south~entral portions of the permit area, as well as from adjacent <br />lands to the west. Scullion Gulch is approximately one-tenth the size of Red Wash, <br />draining an area of 11.7 square miles. Approximately half of the drainage area exists. <br />within the permit area. Map 102 identifies the alluvial deposits mapped by the <br />permittce along Scullion Gulch. The deposits typically range between SO and 200 feet <br />in width, with a depth of about 15 feet. The deposits were mapped by the permittee to <br />a point approximately 1/4 mile upstream from the permit area, where they become <br />discontinuous. At this location, the deposits do not appear to extend any further up <br />the drainage. The permittee again did not quantify the amount of land area occupied <br />by the deposits; however, based on Map 102 it appears the alluvial deposits occupy a <br />few hundred acres. Scullion Gulch is incised.into both the upper sandstone fades and <br />a portion of the middle sandstone fades, both of which are waterbearing rock units. <br />Five stock-watering ponds exist along Scullion Gulch. As in Red Wash, the ponds <br />serve to retain water for stock purposes until it is lost to seepage or evaporation. They <br />do not hold water year round. <br />Based on the width and areal extent of alluvial deposits along Scullion Gulch, the <br />drainage generally meets the geomorphic criteria and therefore qualifies for further <br />consideration as an alluvial valley floor. <br />Water Availability Criteria -Artificial Flood Irrigation <br />As with Red Wash, flow events along Scullion Gulch were monitored using a crest <br />stage gage. During the two yeaY inventory period conducted by the permittce, only <br />three nrnoff events were recorded, the highest event measuring 185 cfs. Again, <br />however, crest-gage data has only limited application for AVF purposes. The mean <br />annual yield estimations provided by the permittce are more applicable for identifying <br />the amount of water which may be expected for Scullion Gulch. The permittces' <br />estimations, derived using Grunsky's formula, indicate that the potential average <br />annual water yield from the Scullion Gulch watershed is 202 acre feet. This <br />corresponds to approximately 0.34 inches of nrnoff. The amount of water available <br />annually, as estimated through this method, indicates that Scullion Gulch warrants <br />further consideration as a potential alluvial valley floor. <br />Subirrigation <br />As with Red Wash, the presence of subirrigation along Scullion Gulch was investigated <br />by the permittce based on the type of vegetation present along the drainage. The <br />permittee has identified a big sage bnush - greasewood community along the entire <br />length of unconsolidated alluvial deposits identified on Map 102, and concludes that <br />water is available to the vegetation "on a limited and sporadic basis". The big sage <br />brush-greasewood community, however, is more spazse compazed to that community <br />found along Red Wash, indicating that the availability of subsurface water is much <br />more limited in Scullion Gulch. Further evidence of the general lack of subirrigation <br />can be gleaned from [he permittee's surface facilities geotechnical investigation, <br />contained in Illustration 18 of the permit application. Six exploration holes, sited at <br />28 <br />