Award Date

1-1-2008

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Water Resource Management

First Committee Member

Charalambos Papelis

Number of Pages

95

Abstract

The Salt River travels through the urban areas of Maricopa County and its flows are fed primarily by treated wastewater, shallow groundwater, urban runoff, industrial effluent, agricultural runoff, and storm water runoff before merging with the Gila River and eventually the Colorado River. The population growth in Maricopa County has influenced the flows of the Salt River for more than a century. The past century has seen major flooding in the valley and the construction of erosion control structures has been part of an effort to reduce damages due to flood events. These structures affect the flow of sediment through the Salt River and may affect the distribution of potential contaminants in a way that can negatively impact plant and animal life; The chemical constituents examined in this study are arsenic, boron, selenium, and phosphorus. Sediment samples were collected from above and below each of the erosion control structures and at other sites within the urban areas of the river using appropriate sampling techniques to obtain representative samples. Physicochemical characterization of the samples, including particle size distribution, specific surface area analysis, particle morphology, and mineralogy, was performed. Previous studies in the Las Vegas Wash have indicated that arsenic, boron, phosphorus and selenium are elements of concern in urban watersheds and were extracted from the sediments and analyzed to determine concentrations. The physical characteristics of the samples were compared to elemental concentrations in order to determine the relationship between those characteristics and the concentration and distribution of the elements of concern. In addition, elemental concentrations were compared to the location of the samples in the Salt River to determine how the erosion and other control structures might affect elemental distribution. The results show that samples located immediately downstream of erosion control structures and that have an above average surface area are more likely to have higher than average concentrations of arsenic, boron, and phosphorus. This study shows the significance of detailed sediment characterization in the interpretation of elemental distribution trends in the Salt River and other similar systems in the arid Southwest. Methods used in this study will be useful in future studies in the Salt River and in other urban watersheds in arid and semi-arid regions.

Keywords

Arizona Control; Distribution; Effects; Erosion; Metals; Nutrients; River; Salt; Sediments; Selected; Structures

Controlled Subject

Hydrology; Geochemistry; Environmental engineering

File Format

pdf

File Size

1648.64 KB

Degree Grantor

University of Nevada, Las Vegas

Language

English

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