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<br />
<br />Annual Dissolved-Solids Loads
<br />
<br />The annual dissolved-solids loads for water
<br />years 1970-93 for the four gaging stations in the
<br />Grand Valley area are listed in table I. Also includ-
<br />ed in table I are the mean, standard deviation, and
<br />95-percent confidence interval of the mean for the
<br />annual loads. If the population is normally distributed,
<br />the true population mean will be within the 95-percent
<br />confidence interval on average 95 percent of the time
<br />(Helsel and Hirsch, ] 992).
<br />
<br />Based on the mean annual loads for 1970-93
<br />in table I, about 46 percent of the dissolved-solids
<br />load of about 3.32 million tons in the Colorado River
<br />near the State line (station 09163500) was in the
<br />Colorado River upstream from the Grand Valley
<br />(siaiions 09095500 plus 09105000), 38 pen.:t:ni came
<br />from the Gunnison River (station 09152500), and
<br />16 percent was from the Grand Valley. Considerable
<br />variation in annual loads between years is evident for
<br />each station. Some of the variability is related to
<br />streamflow, because years with the largest dissolved-
<br />
<br />Table 1. Annual dissolved-solids loads for four gaging stations in the Grand Valley area and the annual Grand
<br />Valley dissolved-solids load, water years 1970-93
<br />[Annual loads in tons; upper and lower 95-percenl confidence intervals (95% CI) are the upper and lower 95% CI of !.he mean]
<br /> Statton Station Statton Station Grand Valley
<br />Water year 09095500 09105000 09152500 09163500 dlssolved-
<br /> aolldaload
<br />1970 1,587,000 68,100 t,579,000 3.772.000 538.000
<br />1971 1,616,000 65,100 1,391,000 3.635,000 563,000
<br />1972 1,454.000 53,100 1,052,000 3,473,000 914,000
<br />1973 1,518,000 71.600 1,323,000 3,711,000 798,000
<br />1974 1,473,000 54.800 1,435,000 3,536,000 573,000
<br />1975 1,529,000 58,300 1,330,000 3,284,000 367,000
<br />1976 I,4M,OOO 46.700 1.294,000 3,010,000 265,000
<br />t977 1,183,000 22.800 955,000 2,343,000 182,000
<br />1978 1,364,000 48,000 1,026,000 2,964,000 526,000
<br />1979 1,509,000 79.200 1,446,000 3,450.000 416.000
<br />1980 1,523,000 60.500 1,225,000 3,195.000 387.000
<br />1981 1,157.000 44.700 877,000 2,729,000 650,000
<br />1982 1.279,000 49.700 1,225,000 3,103,000 549,000
<br />1983 1,779,000 68.900 1,558,000 4,014,000 608,000
<br />1984 2,053,000 81,800 1,758,000 4,577,000 684,000
<br />1985 2,014,000 81.700 1,489,000 4,258,000 673,000
<br />1986 2.004,000 79,100 1,464,000 4,2M,000 657.000
<br />1987 1,534,000 59,900 t,534.000 3,594.000 466,000
<br />1988 1,352.000 52.900 I,M3,OOO 2,9t8,OOO 470,000
<br />1989 1,232,000 48.100 880,000 2,768,000 608,000
<br />1990 1,101,000 42.300 857.000 2,317,000 317.000
<br />1991 1,218.000 47,400 1.064,000 2,7 t 8,000 389,000
<br />1992 1,185,000 46.000 1,160.000 2,780.000 389.000
<br />t993 1,501.000 60,000 1,402,000 3,407,000 444.000
<br />Annual mean 1,482,000 57.900 1,265,000 3,323,000 518,000
<br />Standard deviation 268,000 t4,500 252,000 592,000 t69,000
<br />Upper 95% Cl 1,589,000 63,700 1.366.000 3,560,000 586,000
<br />Lower 95% Ct 1,375.000 52.100 t.I64,OOO 3.086,000 450,000
<br />
<br />8 Trend Analysis of Selected Water-Quality Data Associated With Salinity-Control Projects In the Grand Valley,
<br />In the Lower Gunnison River Basin, and at Meeker Dome, Western Colorado
<br />
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