• Invited Topical Speaker: John D. Hem, Water-Quality Studies Today and Tomorrow

      Hem, John D.; U.S. Geological Survey, Menlo Park, California (Arizona-Nevada Academy of Science, 1973-05-05)
      Development of better instruments for analysis and automation have greatly increased the available information on quality of water during the past decade. There remains a need for further research on relationships between dissolved material and the solids in contact with water in order to cope with existing or potential problems in water quality such as the extent to which lead from automobile exhausts may contaminate water supplies, or the safety of disposal of toxic wastes into deep saline aquifers.
    • Lake Powell Research Project: Hydrologic Research

      Jacoby, Gordon C.; University of California at Los Angeles (Arizona-Nevada Academy of Science, 1973-05-05)
      The Lake Powell Research Project is investigating the effects of man's activities on the Southeastern Utah-Northeastern Arizona region. A major portion of this project is devoted to the hydrology of Lake Powell, the largest recent modification in the region. This hydrologic research is separated into the following subprojects and administrative institutions: Subprojects: Streamflow Trends, Evaporation, Bank Storage / Institution: University of California at Los Angeles. Subprojects: Sedimentation, Physical Limnology, Lake Geochemistry / Institution: Dartmouth College. The project is now concluding its first year of full-scale research effort. The UCLA subprojects are aimed at developing an overall water budget for the lake, both on an annual and long -term basis. The Streamflow_trends study indicates that the Upper Colorado River Basin (UCRB) has shifted from a few extraordinarily wet decades in the early 1900's to several relatively dry decades up to the present. Evaporation efforts so far are toward installing a data collection system capable of furnishing data for mass-transfer and energy-budget calculations. The bank-storage study indicates that bank storage constitutes a large fraction of the impounded waters. Secondary as well as primary permeability may be of major importance in bank storage. The Evaporation and Bank Storage subprojects are working in close coordination with the Bureau of Reclamation. The Sedimentation subproject has shown that the rate may be in general agreement with earlier estimates from river flow and suspended sediment data. However, the distribution is affected by sediment dams formed by slumping of canyon wall material. Physical limnology studies indicate the presence of stratifications resulting from thermal and turbidity layers causing complex movements within the lake waters. Field and laboratory efforts in lake geochemical analyses indicate that the precipitation of calcium carbonate may be the most important chemical process in changing the water quality of the lake.