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Temperature (°C), conductivity (µS/cm), turbidity (ntu), dissolved oxygen (mg/L), pH, and dissolved oxygen saturation (%) and density (kg/m3, calculated) in the main channel of Lake Powell, Sept. 4-8, 2003. Penstock elevation is at 1057.7 m (-42.7 m), river outlet at 1028.4 m. Reservoir elevation is 1098.5 m /3603.7 ft above sea level. Profile measurements indicated by dots on temperature plot, sample points indicated by +. Download Windows Metafile Format |
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Observation of conditions in Lake Powell helps project future conditions expected below the dam. The recent lake-wide survey of Lake Powell (on the main channel of the Colorado River arm) demonstrates conditions that will be eventually exported through the dam after further transformation and surface mixing this fall. Of primary concern is the unusually low oxygen levels found in the lower epilimnion (purple stippled area). The location and intensity of this hypoxiaor low dissolved oxygen, approaching 0 mg/l, have not been reliably reported before in the history of the reservoir's monitoring. Fall mixing will integrate the surface D.O. depletion with more enriched surface waters, but the fall trend of overall oxygen depletion will also overlay these results. These effects will be monitored to anticipate downstream conditions. |
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