• 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.
    • Use of Stock Ponds for Hydrologic Research on Southwest Rangelands

      Simanton, J. R.; Osborn, H. B.; USDA, ARS Soil, Water, and Air Sciences; Southwest Rangeland Watershed Research Center, Tucson, Arizona (Arizona-Nevada Academy of Science, 1973-05-05)
      Five livestock watering ponds on the walnut gulch experimental watershed were instrumented to evaluate the use of these ponds as a method for comparing rainfall amounts with runoff sediment volumes. Pond drainage area, vegetative cover, soil type, percent slope, and years of record were tested. Instrumentation consisted of water level recorders, and a topographic survey of each stock pond to ascertain its storage capacity. The results to date have been insufficient to reach definite conclusions due to instrumentation and surveying problems, and because of the natural variability of thunderstorm rainfall. Since most of these problems have now been corrected, future data should yield valuable hydrologic data for semiarid rangelands by means of these instrumented stock ponds.