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• An irrigation ditch does cross the northern part of the Nucla Mine permit area. The ditch is not <br />disturbed by mining nor does the ditch receive any water from the mine area. <br />In regard to the agricultural water quality standards, the San Miguel River water delivered by the <br />irrigation ditches is more suitable for irrigation purposes than the waters in Tuttle or Calamity Draw. <br />The agricultural suitability (National Academy of Sciences, 1972) of surface water in Calamity and <br />Tuttle Draws falls within the category of water that can only be used for salt tolerant plants on <br />permeable soils with careful management practices (TDS from 2,000 to 5,000 mgp). Using the same <br />classification system, water supplied by the West Lateral irrigation ditch (San Miguel River) (TDS 500 <br />mgR) will have no detrimental effects on plants. Waters of Tuttle and Calamity Draws have <br />commonly exceeded the manganese and pH agricultural standards. <br />Since the early part of this century, it has been a regional practice to obtain water for irrigation from <br />the San Miguel River. Because of the incised nature of the stream channel, it is impossible to flood <br />irrigate from either Tuttle or Calamity Draw. From field reconnaissance investigations, it has also <br />been determined that water pumpage from these draws for irrigation purposes is not occurring. <br />Subimigation. A small amount of subirrigation does occur along the Tuttle and Calamity Draw stream <br />channels. Much of the alluvial ground water along these draws is a result of seepage from the <br />• irrigation ditches. In many areas where the subirrigation occurs, the vegetation and soil quickly dry <br />up when the ditch is turned off from October to April. The subirrigation along Tuttle or Calamity <br />Draw is not considered extensive enough to support agricultural development. <br />Conclusion. The CMLRD concluded in its Decision and Findings of Compliance Document (1983) <br />that no alluvial valley floors exist in either the Nucla permit area or the potentially affected area <br />(Tuttle Draw) associated with the Nucla Mine. <br />Finally, based on geomorphic criteria alone, neither Tuttle or Calamity Draws meet the necessary <br />criteria to be identified as alluvial valley floors, as they display geomorphic features that are <br />indicative of upland areas rather than alluvial valley floors. <br />National Academy of Sciences. 1972. Water Ouality Criteria 1972: National Academy of <br />Engineering. Washington, D.C. p. 335. <br />Rahn, P.H. 1976. Potential of Coal Strip Mine Spoils as Aquifers in the Powder River Basin: <br />Project No. 10470025, Old West Regional Commission, Billings, MT. 108 p. <br />• <br />16-9 <br />