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<br />l\) <br />,~ <br />- <br /> <br />Heasurement of several parameters in the River indicative of dissolved salts <br /> <br />-..1 <br />w <br /> <br />(chloride, conductivity, alkalinity, r~rdness and soaitJ::J) followed a general <br /> <br />pattern. Lo~er ccn~er.t~aticns were obtained in ~he upstream reaches abo~e <br /> <br />Glen;.tood Springs. A rapid increase was noted immedidtely downstream from the <br /> <br />springs in the GZunwood area followed by a gradual increase as the River flows <br /> <br />west toward.:;; Grand Junction. Decreases in dissolved salts were measured below <br /> <br />tbe confluences of both the Gu~~ison and Roaring Fork RiVers. TO illustrate <br /> <br />the above phenomenom, the average conductivities for each station froQ January <br /> <br />to March, 1974 have been graphed in Figure 2. <br /> <br />Individual conductivities ranged from 529 wnhos (:nicromhos) at CR-l on <br /> <br />April l, 1974 to 1273 ~nhos at CR-20 on January 2, 1974. specific conducti'lities <br /> <br />in excess of 500 umbos is an indicator of highly mineralized waters but not <br /> <br />necessarily degraded water. <br /> <br />Alkalinity determinations increased at a slower rate ~~n ot~er cr~nUcal <br /> <br />constitutents of the water. There was about a one-~iird increase in alkalin~ties <br /> <br />from Dotsero to the border while hardnesses increased up to 400%. The highest <br /> <br />alkalinity concentration was 224 ppm at CR-] i~diately below the hot springs <br /> <br />of Glenwood Springs on March IS, 1974. At CR-4, approximately three-fourths of <br /> <br />a mile downstreaC't from CR-) and one-half mile downstream frOrl the confluence <br /> <br />of the Colorado and Roaring Fork Rivers, the alkalinity concentration was 120 ppm. <br /> <br />Chloride concentrations also 7aried extensively and rapidly. On .~rch 18, <br /> <br />1974, the chloride co~ce~tration above the hot springs in Glenwood Springs was <br /> <br />32 ppm, belQ~ the springs 120 ppm, and below the Roaring Fork confluence 92 ppm. <br /> <br />Below tr~ confluence of the Gunnison and Colorado Rivers, the reduction of c.~oride <br /> <br />-11- <br />