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sult of groundwater storage in the formations underlying the White River <br />Plateau. The average annual groundwater contribution to the White River above <br />Rangely, Colorado is 431.5 cubic feet per second, which is 64.2 percent of the <br />total annual flow of 672 cfs (page II C-28). The majority of flow in the White <br />River occurs between May and July in response to snowmelt, yielding flows dur- <br />ing the inventory period at the mine that approached 1,840 cfs on June 12, <br />1979. Average monthly flow distributions show a maximum volume in June of ap- <br />proximately 92,000 acre feet (Figure II C-10). Flows begin to decrease in <br />July, increase slightly in October, perhaps in response to thunderstorm activi- <br />ty, and decline steadily until precipitation increases again in March. <br />Surface water quality in the White River is characterized as a calcium-sulfate <br />type. Even so, ionic concentrations of sodium and magnesium can approach or <br />exceed those of calcium. Richards (1954) has been cited as stating that com- <br />plexes resulting from these concentrations may, however, keep sodium hazards <br />low. Seasonal variations in water quality are tied to flow derivation - for <br />example, dissolved solids concentrations decrease in May and June when high <br />flows derive from snowmelt. This dilution effect subsides during periods of <br />low flow when groundwater contributes proportionately more, and dissolved <br />solids concentrations tend to rise. Conversely, high snowmelt flows carry an <br />increased concentration of suspended solids. Same chemical constituents, such <br />as total iron and manganese, are associated with sediment. Therefore, these <br />constituents also increase during high flows (page II.C-55). <br />Most of the samples taken during the inventory period show total iron concen- <br />trations that exceed effluent limitations which could indicate an acid problem <br />and low manganese concentrations. The pH levels are within an acceptable range <br />of 6.0 to 9.0 and tend to be basic. This along with measured low acidity and <br />high alkalinity indicates that acid mine drainage should not be a problem <br />during mining in the permit area and is not anticipated. Ammonia and phosphate <br />concentrations are higher than accepted limits of .02 mg/1 and .O1 mg/1, <br />respectively. The former is probably due to animal waste and fertilizer <br />degradation while the applicant has credited McElroy's (1976) proposal <br />4 <br />