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Show Table 1. History of the Bureau of Reclamation major ion chemistry and physical limnology monitoring program in Lake Powell. Period Program Description 1965- 1971 Six stations ( Wahweap Bay, Padre Bay, Oak Canyon, Cha Canyon, Hall's Crossing, and Hite) were monitored quarterly at 50' depth intervals ( top to bottom) for physical parameters including temperature and dissolved oxygen, and chemical parameters including specific conductance, TDS, pH, and common ions ( Jerry Miller, U. S. Bureau of Reclamation, personal communication, 1986). 1971- 1984 Seven stations ( Wahweap Bay, Padre Bay, Oak Canyon, Cha Canyon, Halls Crossing, Good Hope Mesa, and Hite) were monitored monthly at 50' depth intervals for physical parameters including temperature and dissolved oxygen, and chemical parameters including specific conductance, TDS, pH, and common ions ( calcium, sodium, magnesium, potassium, chloride, sulfate, alkalinity, and bicarbonate) ( Jerry Miller, U. S. Bureau of Reclamation, personal communication, 1986). In addition, a special two- year study occurred in 1981- 82 that focused on nutrients and productivity ( Paulson and Baker, 1984). 1984- present With an extensive data base established from 1965- 1984, the Bureau of Reclamation elected to reduce sampling to a quarterly basis. An eighth site ( Cataract Canyon) was added to the seven sites previously listed. Parameters sampled remain the same except for the addition of silica to the parameter list. In addition, continuous recording ( at 2 hour intervals) at three depths for temperature and specific conductance has been attempted at two sites ( Cataract Canyon and Clearwater Canyon). Because of instrumentation problems, only intermittent data are available ( Jerry Miller, U. S. Bureau of Reclamation, personal communication, 1986). 17 |