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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 mg/1). Using the <br /> same classification system,water supplied by the West Lateral irrigation ditch(San Miguel River) <br /> (TDS 500 mg/1 or lower)will have no detrimental effects on plants. Waters of Tuttle and Calamity <br /> Draws have 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 difficult 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 occurring <br /> infrequently. <br /> Subirri ag tion <br /> A small amount of subirrigation does occur along the Tuttle and Calamity Draw stream channels. <br /> Much of the alluvial ground water along these draws is a result of seepage from the irrigation <br /> ditches. In many areas where the subirrigation occurs,the vegetation and soil quickly dry up when <br /> the ditch is turned off from October to April. The subirrigation along Tuttle or Calamity Draw is <br /> not considered extensive enough to support agricultural development. <br /> Conclusion <br /> The DRMS concluded in its Decision and Findings of Compliance Document(1983)that no alluvial <br /> valley floors exist in either the New Horizon permit area or the potentially affected area (Tuttle <br /> Draw) associated with the New Horizon Mine. New Horizon concludes, based on the following <br /> criteria,that no alluvial valley floors exist along the potentially affected area of Calamity Draw <br /> associated with the New Horizon 2 mining area. Water availability, quality, the limited extent of <br /> the unconsolidated streamlaid deposits and subirrigated areas, and the incised nature of <br /> Calamity Draw make it infeasible and impractical to construct a flood irrigation system <br /> employing gravity drainage. This conclusion is substantiated by the results of an EPA alluvial <br /> valley floor study (EPA 1977) which addresses most coal mining areas of the west and the <br /> fact that flood irrigation is not being practiced along Calamity Draw. <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 /> January 2017 (TR-77) 2.05.6(3)-10 <br />