title: Physical, chemical, and mineralogical characteristics of a reservoir sediment delta (Lake Powell, U.S.A.) and implications for water quality during low water level.
abstract: 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 elementsnearer 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.
authors.affiliation: Environmental Science and Engineering, California Institute of Technology, Caltech MC 138-78, 1200 East California Blvd., Pasadena, CA 91125, USA. rwildman@hsph.harvard.edu
authors.forename: Richard A
authors.initials: RA
authors.lastname: Wildman
authors.forename: Lincoln F
authors.initials: LF
authors.lastname: Pratson
authors.forename: Michael
authors.initials: M
authors.lastname: DeLeon
authors.forename: Janet G
authors.initials: JG
authors.lastname: Hering
mesh_terms: D001130:Arizona; D004602:Elements; D004784:Environmental Monitoring; D005618:Fresh Water / Q000737:chemistry*; D019015:Geologic Sediments / Q000737:chemistry*; D008903:Minerals / Q000032:analysis*; D010316:Particle Size; D014589:Utah; D014881:Water Supply
chemical_list: D004602:Elements; D008903:Minerals