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.tl ;':'~_i ~' -:"'1 '.! ~, I?~~ (1'.' '.! I:~i ~J ;--~; . .:~ l!l...,.:, t.:~ ~~:'~ ~.~.:~ e~ 11 &~ P"l It;] .;:1 ~, ~~ ~.,. .~:~ to ;~ .. ~..i .".~ iJ Eq ,.... ;i~~i Eil If.~ . .:~ f'. -::~ ...-~ '.':.( .E" -;.-.', '.' .~ ... .'.' >:"., F.,".' , ,,: f..... ..-,' /~ nO~O~8 Oxygen is subject to the gas solubility laws, so both pressure and temperature affect its solubility in water. Therefore, as water temperature and elevation decrease, oxygen solubility increases. The dissolved oxygen data plus its percent saturation appear in the data presentation while the graph in Figure IV shows how .the dissolved oxygen decreased with depth in the reservoir. " Analysis of the data shows values near 100 percent saturation for the stream stations, supersaturation for the surface of the res- ervoirs, and very low values at the subsurface reservoir stations. The corresponds with expected results in waters with such aquatic vegetation. The supersaturated values are likely due to the photo- synthesis of the algae during the day. A 24-hour sampling of dissolved oxygen would probably show a decrease in dissolved .oxygen at night because the vegetation would still be respiring but not photosynthesizing. Thus, oxygen production would cease at night, but the respiration process would continue to demand oxygen and release carbon dioxide. Troutrequir~ 6 ~i/:l'of di;solved oxygen which is the Colorado BI minimum standard. Thus, at this time of year, fish must. stay near the top 0-20 feet of water in the reservoir. As the eutrophica- tion'processcontinues, the decomposition or aquatic plants plus their life.processes can put a severe demand in oxygen reserves and eventually be a hazard to fish life. This will likely not occur at Williams Creek, however, because ofa good inflow to capa,city ratio. D. Specific Conductance, Hardness, Alkalinity, Acidity, and J:'H Chapter briefly .Creek. IV contains the actual data. discussed and then applied to Here, each parameter is the situation at Williams A substance is said to be alkaline if it will neutralize hydrogen ions. Alkalinity is caused by strong bases and the salts of strong alkaline and weak acids. A substance is acid if it will neutralize hydroxyl ions. Acidity in a stream is caused by carbon dioxide, mineral acids, and the salts of strong acrds and weak bases. The amount of hydrogen ion activity is expressed by the pH which represents the negative ion base 10 of the hydrogen ion activity in meles per liter. The pH s"ale ranges from 0 to 14 ~ith a pH of 7.0 being a neutral solution. At that point, the H activity equals the OH activity. As the pH .decreases,the hydrogen ion activity increases and the solution is more acid. Most natural streams have a pH between 6.5 and 9.0. The term "buffering capacity" refers to the amount of acid or base required to produce a unit change in pH. Therefore, a stream is buffered if its pH would not be greatly changed by the addition of.an acid or a base. The major buffering system in natural waters is the carbonate system. Following is the reaction of carbon dioxide in water: '~L',!,;