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<br />'" <br />(.:; <br />--.J <br />w <br /> <br />Measurement of several parameters in the River indicative of dissolved salts <br /> <br />(cr2oride, conductivity, a~kalinity, r~rdness and sodi~) followed a general <br /> <br />pattern. Lv~e: cc~~e~t~atjcns ~ere obtained in the upstream reaches abo~e <br /> <br />Glen:.rood Springs. A rapid increase was noted immediately downstream from the <br /> <br />springs in the GZunwood area followed by a gradual increase as the River flows <br /> <br />west toward~ Grand J~ccion. Decreases in dissolved salts were measured below <br /> <br />tbe COnfluences of both the Guru~ison and Roaring Fork Rivers. <br /> <br />To illust.::ate <br /> <br />the above phenomenom, the average conductivities for each station fro~ January <br /> <br />to Harch, 1974 have been graphed in Figure 2. <br /> <br />Individual corlductivities ranged fro.7J 529 umi::os (:nicromhos) at CR-l on <br /> <br />April I, 1974 to 127) umbos at CR-20 on January 2, 1974. Specific cond~cti7ities <br /> <br />in excess of 500 ~~~s is an indicator of highly mineralized waters b~t not <br /> <br />necessarily degraded weter. <br /> <br />Alkalinity determinations increase~ at a slower rate t:~n other cr~mical <br /> <br />ccnstitutents of the water. There was about a one-~~rd increase in alkalinities <br /> <br />from Dotsero to t.he border while r..ardnesses increased up to 400~. The highest <br /> <br />alkalinity concentration was 224 ppm at CR-] immediately below :~~ hot springs <br /> <br />of Glen~d Springs on March 18, 1974. At CP.-4, approximately three-f~urtr~ cf <br /> <br />a mile downstrea.m from CR-) and one-half mile downstream from tbe confluence <br /> <br />of tbe Colorado and Roaring Fork Rivers, tbe alkalinity concentration was 120 ppm. <br /> <br />Cll10ride concentrations also 'laried extensi./ely and rapidly. On .'-!arcb 18, <br /> <br />1974, the c~cride concentration above the bot springs in Glenwood Springs was <br /> <br />32 ppm, belo~ the springs 120 ppm, and below the Roaring FOrk confluence 92 ppm. <br /> <br />Below the confluence of the G~ison and Colorado Rivers, the reduction of chloride <br /> <br />-11- <br />