Physical, Chemical, and Mineralogical Characteristics of a Reservoir Sediment Delta (Lake Powell, USA) and Implications for Water Quality during Low Water Level
- Richard A. Wildman *ab,
- Lincoln F. Pratsonc,
- Michael DeLeond and
- Janet G. Heringae
- a Environmental Science and Engineering, California Institute of Technology, Caltech MC 138-78, 1200 East California Blvd., Pasadena, CA 91125
b current address, Harvard University Center for the Environment and Harvard School of Public Health, Harvard Univ., Landmark Center, West Wing, 4th Floor, 401 Park Drive, Boston, MA 02215
c Nicholas School of the Environment, Duke Univ., 203 Old Chem, Box 90227, Durham, NC 27708
d Spectro Analytical Instruments, Inc., Ametek, Materials Science Division, 91 McKee Dr., Mahwah, NJ 07430
e J.G. Hering, current address: Eawag, The Swiss Federal Institute of Aquatic Science and Technology, Überlandstrasse 133, 8600 Dübendorf, Switzerland. Assigned to Associate Editor Géraldine Sarret
Lake Powell is a large reservoir in Utah and Arizona that has experienced large changes in water level during a recent drought. As a first step in assessing the connection between hydrologic and chemical changes at Lake Powell, we characterized the particle size and solid-phase bulk concentrations for 31 elements and 25 minerals in sediment from the inflow region and some shoreline locations by using laser diffractometry, X-ray fluorescence, elemental analysis, and X-ray diffraction. Our results are consistent with previous results that show a negative correlation between particle size and concentrations of most elements and most minerals other than quartz and some feldspars. In our samples, however, solid-phase iron, rather than particle size or organic carbon, is the best predictor variable for the solid-phase concentrations of elements and minerals. Sediment characteristics vary on a scale of tens of kilometers, with fine sediment that is enriched in trace elements nearer to the dam. These trends allow formulation of an algorithm for determining a water-level threshold below which sediment resuspension may alter water chemistry in a generic reservoir with a long and narrow sediment delta.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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