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Surface water at all stream sites, except SW-N104, SW-N105, and SW-N106, was found to be <br />unsuitable for drinking water because of sulfate and manganese excedences. Lead and iron <br />standards were exceeded at four of the sites, while pH and nitrogen-ammonia (NH.) were exceeded <br />at three and one stream monitoring site, respectively. Interestingly, the three sites located on the <br />West Lateral irrigation ditch all fell within the drinking water standards. Historically and presently, <br />irrigation water delivered by the West Lateral has been and currently is used by local residents as <br />a source of drinking water. Sulfate and manganese are commonly exceeded at all other stream <br />sites established in tributaries of and along both Calamity and Tuttle Draws. <br />With regard to the agricultural standards, only manganese was exceeded at all surface water <br />monitoring sites, with the exception of the West Lateral irrigation ditch sites (SW-N104, SW-N105, <br />SW-N106). Five sites have had exceedences of the pH standard and two sites have had <br />exceedences of boron. <br />Manganese was exceeded commonly in both Tuttle and Calamity Draws, as well as at sites located <br />along tributaries to each drainage (SW-N6, SW-N7, NPDES 001 and 006, and SW-N102). <br />Based on a classification of salinity hazard for and and semi-arid areas (National Academy of <br />Sciences, 1972), surface water in Calamity and Tuttle Draws all fall within the category of water that <br />can be used for tolerant plants on permeable soils with careful management practices (TDS from <br />2000 to 5000 mg/1). According to this classification system, water supplied by the West Lateral <br />irrigation ditch (TDS 500 mg/1) will have no detrimental effects on plants. <br />Using mean values for sodium adsorption ratio (SAR) and specific conductance (SC, umhos/cm <br />at 25°C) from each site determined for both the irrigation and non-irrigation season, water <br />classifications were made based on guidelines proposed by the U.S. Salinity Laboratory (1954). <br />During periods of irrigation (mid-April through mid-October), all surface water sites exhibit a low <br />sodium hazard and a medium to high salinity hazard. Between irrigation seasons (with the <br />exception of West Lateral Irrigation Ditch sites), all sites can be classified as having a low sodium <br />hazard and a high to very high salinity hazard. <br />As a result of the request made by OMLR to Peabody in a letter on May 4, 1986, Peabody revised <br />2.04.7-46