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<br /> <br />Except for the first measurements in January 1985, specific conductance <br />from profiles in Kenney Reservoir (tables II and 12 in the "Hydrologic Data" <br />section; fig. 6) ranged from 374 to 932 ~S/cm. Periodic measurements of <br />specific conductance in the White River at site 3 ranged from 375 to 963 ~S/cm <br />during water years 1985-87. The large specific-conductance values (972 and <br />1,550 ~S/cm) measured in January 1985 (table 11 in the "Hydrologic Data" <br />section) near the bottom of the reservoir at site 1 were measured soon after <br />the reservoir filled. These large values were not repeated in subsequent <br />measurements and were attributed to large values of specific conductance from <br />residual ground-water seepage (Van Liew and Gesink, 1985, p. 20-28) and(or) to <br />leaching of dissolved ions from material associated with the dam construction <br />and reservoir-site preparation. <br /> <br />The data in figure 6 indicate little variation in specific conductance <br />with depth. The slight lateral differences in specific conductance within the <br />reservoir (tables II and 12 in the "Hydrologic Data" section) are related to <br />changes in inflow discharge and time of travel within the reservoir. Specific <br />conductance was least during snowmelt runoff in May and June and greatest <br />during low flow in fall and winter. <br /> <br />Using the analysis of covariance test, the ratios of specific conductance <br />to concentrations of dissolved solids for all samples in the reservoir were <br />compared with the ratios of specific conductance to concentrations of dis- <br />solved solids for the White River at site 3. The test indicated no <br />differences at the 0.05 level of significance for the range o! data. The <br />relation of dissolved-solids concentration to specific conductance in the <br />reservoir and in the White River at site 3 is shown in figure 7. Dissolved- <br />solids concentrations can be estimated from specific-conductance measurements <br />in the reservoir and (or) the White River by using the regression shown in <br />figure 7. However, since the reservoir may not be in a steady-state condi- <br />tion, additional measurements of specific conductance and dissolved-solids <br />concentrations need to be done to ensure that this relation can be used as a <br />predictive tool. <br /> <br />E!! <br /> <br />Hydrogen ion activity (pH) is a measure of the acid-base characteristics <br />of water. Water that is neutral has a pH of 7.0; however, pH of natural water <br />that contains dissolved constituents commonly ranges from 5.0 to 9.0, and more <br />frequently from 6.5 to 8.5 (Hem, 1985, p. 64). The constituents carbon <br />dioxide (C02), bicarbonate (HCOs), and carbonate (COs), which account for most <br />alkalinity, greatly affect or buffer pH in natural water (Hem, 1985, p. 106). <br /> <br />Diel shifts in pH can develop in water that has considerable biological <br />production and small ionic concentrations (Allen, 1972). Values of pH may <br />increase to greater than 9.0 when phytoplankton use dissolved C02 and HCOs <br />during photosynthesis. Conversely, diel and seasonal decreases in pH to <br />values less than 7.0 can occur when C02 from decomposition and respiration <br />accumulate in poorly mixed water. If exposure time is sufficient, these <br />environmental changes may be harmful or lethal to some aquatic life (National <br />Academy of Sciences, 1972). <br /> <br />16 <br />