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<br />Major Ions and Dissolved-Solids Loads <br /> <br />Major ions that account for most of the dissolved <br />solids in natural waters are listed below: <br /> <br />Catlona <br />(positive charge) <br /> <br />Anions <br />(negative charge) <br /> <br />Calcium (Ca) <br />Magnesium (Mg) <br />Potassium (K) <br />Sodium (Na) <br /> <br />Alkalinity (CaC03) <br />Bicarbonate (HC03) <br />Carbonate (C03) <br />Chloride (CI) <br />Fluoride (F) <br />Sulfate (S04) <br /> <br />Although noncarbonates can contribute to alka- <br />linity, alkalinity in natural water can be attributed <br />almost entirely to bicarbonate and carbonate without <br />serious error (Hem, 1985). Concentrations of total <br />alkalinity commonly are reported as calcium carbonate <br />(CaC03), in milligrams per liter. In natural waters that <br />have pH values less than 9, bicarbonate is the principal <br />component of alkalinity. Thus, when alkalinity is sig- <br />nificant in the geochemical classification of water <br />(table 7), the bicarbonate component commonly is used <br />for nomenclature purposes. <br /> <br />Concentrations of the major ions and values of <br />stream discharge for sites 1-6 are shown in figures 18- <br />20. Because concentrations of potassium were less <br />than 4.5 mg/L and concentrations of fluoride were less <br />than 0.4 mg/L at all sites during water years 1975-88, <br />potassium and fluoride were considered minor constit- <br />uents and were not included in figures 18-20, In addi- <br />tion, concentrations of major ions, hardness, and <br />dissolved solids were regressed with values of specific <br />conductance. Specific conductance generally is a good <br />indicator of the total ion activity because charged ions <br />in water make the solution conductive. Regression <br />information for sites 1-6 are presented in table 8, <br /> <br />Concentrations of selected major ions at site 4 <br />were graphed chronologically for water years 1975-88 <br />(fig. 21). Data analyses indicated that a substantial <br />decrease in the concentration ranges of sodium, chlo- <br />ride, and, possibly, sulfate occurred after April 1982. <br />Correlation ofthese constituents to specific <br />conductance also changed after April 1982 (fig, 22). <br />Decreases or changes in the above-mentioned constitu- <br />ents during the same period were not evident upstream <br />at site 3. The decreases in sodium, chloride, and sulfate <br />at site 4 probably are related to well recompletions that <br />decreased or eliminated saline ground water that <br />entered the White River in the vicinity of the Meeker <br />dome, Because water chemistry changed at site 4 in <br />1982, data presentations and analyses (fig. 19 and <br />table 8) used to determine relations and ranges of the <br />major ions at site 4 were limited to data collected after <br />April 1982. <br /> <br />Table 7. Chemical criteria used to classify water types and hardness <br /> <br />Mllllequlvalenls per liter <br /> <br />[Water types, modified from Piper, OarreU, and others, 1953. p. 26; bardness, modified from Durfor and Becker, 1964, p. 27] <br /> <br />Cations Anions <br /> <br />Single catioJ1 used when it <br />amounts to 50 percent or <br />more of the total cations; <br />when the above does not <br />exist, the highest two <br />percentages of cations <br />are used. <br /> <br />Single anion used when it <br />amounts to 50 percent or <br />more of the total anions; <br />when the above does not <br />exist, the highest two <br />percentages of anions <br />are used, <br /> <br /> <br />Classlflcstlon <br /> <br />Bivalent cetlons; <br />Calcium and magnesium <br />(milligrams per liter as <br />CaC03) <br /> <br />Less than 60 <br /> <br />Soft <br /> <br />Moderately hard <br />Hard <br />Very hard <br /> <br />61-120 <br />121-180 <br /> <br />More than 180 <br /> <br />36 Sediment Trensport and Water-Quality Characteristics and Loads, White River, Northweelern Colorado, Weler Years <br />1975-88 <br />