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<br />and zinc concentrations approaching or even exceeding <br />those for sediments of the Arkansas River just a few <br />miles downstream from the outfall of California Gulch <br />[19]. California Gulch is the greatest contributor of <br />heavy or trace metals in the upper Arkansas River [20, <br />21]. In years to come, the downstream carry of these <br />heavy or trace metals may accumulate in the Pueblo <br />Reservoir. The environmental impact of such potential <br />downstream loading has not yet been clearly identified <br />[22] . <br /> <br />CONCLUSIONS <br /> <br />The following is a summary of conclusions and recom- <br />mendations based on the data results of this publica- <br />tion: <br /> <br />1. Normal seasonal trends of certain parameters have <br />been slightly altered by the formation of ,Pueblo <br />Reservoir. <br /> <br />2. Surface trends, spatial trends, and depth profiles <br />were also observed for certain dates, parameters, <br />and sites. <br /> <br />3. The dissolved and suspended levels of all the para- <br />meters averaged much less than the recommended <br />or maximum permissible limits of various water <br />use criteria [11]. A very few isolated samples <br />were observed to approach or exceed maximum <br />permissible or recommended limits for the vari- <br />ous beneficial uses. <br /> <br />4. Dissolved oxygen and temperature conditions in <br />the reservoir pool would support salmonid fishes <br />year-around. Observed growth rates of rainbow <br />trout tend to support the belief of prevailing op- <br />timum growth conditions for such cold-water <br />species. <br /> <br />5. Zinc, iron, and manganese concentrations in inlet <br />sediments have increased noticeably when com- <br />pared to baseline pre-impoundment sediments. <br />Other metals may be increasing, but at a slower <br />rate of accumulation or enrichment. It is recom- <br />mended that reservoir sediments be sampled and <br />analyzed on a 3. to 4-year basis. <br /> <br /> <br />6. Annual means, highest monthly means, and low- <br />est monthly means of dissolved and suspended <br />fractions have been reported but not correlated. <br />Additional statistical analysis of the two frac- <br />tions, discharge, suspended matter, and the sedi- <br />ments should provide supportive data regarding <br />loading rates of each parameter and the fate of <br />each. <br /> <br />7. For reasons of reliability due to changing condi- <br />tions, it is recommended that a 1-year study of <br />the dissolved and suspended water fractions be <br />similarly analyzed and studied on an approximate <br />4-year basis. <br /> <br />8. The data, when compared to those of Durum and <br />Haffty [8], Durfor and Becker [7], Kopp and <br />Kroner [9], and Durum, et al. [10] appear to in- <br />dicate that the Arkans<ls River and Pueblo Reser- <br />voir have dissolved solids concentrations in general <br />and trace metals concentrations more specifically, <br />making the Afkansas River and Pueblo Reservoir <br />fairly' average North American surface waters and <br />water supplies. This being the case, it would appear <br />that the data from this study would have wide, <br />spread predictive value when applied to present <br />projects and in assessing the impact on water qual- <br />ity of planned or projected projects of a similar <br />nature given the quality of the water that feeds or <br />would feed such projects. <br /> <br />31 <br />