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• Rule 2: Permits <br />been documented in the Alluvial Valley Floor Investigation (Exhibit 18). A summary of the <br />investigation is presented below. <br />The unconsolidated deposits running through the bottom of Lorencito Canyon are streamlaid and <br />exhibit a relatively high sinuosity compared to other drainages in the permit area. Lorencito <br />Canyon predominantly exhibits intermittent flow with limited reaches of perennial flow. Minimum <br />depths to the water table ranged from 11 to 15 feet while rooting depths in soil were 5 to 6 feet. <br />The materials do not appear to support sub-irrigation, and the site has never been developed for <br />flood irrigation. In summary, Lorencito Canyon does not appear to qualify as an AVF. <br />Cow Canyon consists of unconsolidated colluvial and alluvial materials. Sinuosity is low <br />compared to other channels in the permit area and the channel bottom is bedrock controlled in <br />multiple areas. Channel flow is ephemeral in the upper reaches and intermittent in the lower <br />reaches. Soils are shallower than the minimum recorded depth to water and exhibited no evidence <br />of soil moisture. Unconsolidated materials in Cow Canyon do not support sub-irrigation. The <br />unconsolidated materials in Cow Canyon are limited in lateral extent and would not sustain flood <br />irrigation under standard husbandry practices. Cow Canyon does not appear to qualify as an <br />AVF. <br />The unconsolidated materials in Alamosa Canyon consist of streamlaid deposits of relatively high <br />sinuosity, within a moderately narrow canyon. Useable areas of pastureland are of limited areal <br />• extent, and local practice would not consider flood irrigation. In addition, the stream is <br />intermittent and the minimum recorded depth to the water table is 13.1 feet. The drainage does <br />not appear to support sub-irrigation. Alamosa Canyon does not appear to qualify as an AVF. <br />Chimney, 1?uertecito, and Jeff Canyons contain small areas of limited extent of colluvial and <br />alluvial unconsolidated materials. Sinuosity is low and there is bedrock control of the channel <br />bottom in many locations. Surface water flow is ephemeral. The areas are too small to utilize <br />flood irrigation. The minimum depths to the water table range from 14 to 21 feet, and the <br />sampling of soil profiles in these canyons did not show any evidence of moisture. Chimney, <br />I'uertecito and Jeff Canyons do not appear to have alluvial valley floors as defined by Surface <br />Mining Control and Reclamation Act (SMCRA). <br />The unconsolidated materials identified along the Purgatoire River on Map 2.05.7-2 are <br />characterized as alluvial valley floors (AVFs). The materials are streamlaid, adjacent to a <br />perennial stream which supports traditional flood irrigation practices, and appear to have a shallow <br />water table which would sustain sub-irrigation (Table 2.06.8-1). Lorencito Coal Company is <br />planning to disturb a small portion of the Purgatoire River alluvial valley floor and interrupt <br />farming activities during the period of operation. The following discussion will document that <br />this disturbance is of such small acreage that it will result in a negligible impact to the Hill <br />farming operation. <br />The Lorencito Canyon Mine access road utilizes a historic ranch road, and crosses the Purgatoire <br />River AVF. LCC is expanding the road from a 12-foot running surface to a 30-foot surface, an <br />2.06-3 (Revise 10/4/01) <br />