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Monitoring urban impacts on suspended sediment, trace element, and nutrient fluxes within the City of Atlanta, Georgia, USA: Program design, methodological considerations, and initial results

Hydrological Processes

By:
, ,
DOI: 10.1002/hyp.6699

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Abstract

Atlanta, Georgia (City of Atlanta, COA), is one of the most rapidly growing urban areas in the US. Beginning in 2003, the US Geological Survey established a long-term water-quantity/quality monitoring network for the COA. The results obtained during the first 2 years have provided insights into the requirements needed to determine the extent of urban impacts on water quality, especially in terms of estimating the annual fluxes of suspended sediment, trace/major elements, and nutrients. During 2004/2005, suspended sediment fluxes from the City of Atlanta (COA) amounted to about 150 000 t year-1; ??? 94% of the transport occurred in conjunction with storm-flow, which also accounted for ??? 65% of the annual discharge. Typically, storm-flow averaged ??? 20% of theyear. Normally, annual suspended sediment fluxes are determined by summing daily loads based on a single calculation step using mean-daily discharge and a single rating curve-derived suspended sediment concentration. Due to the small and 'flashy' nature of the COAs streams, this approach could produce underestimates ranging from 25% to 64%. Accurate estimates (?? 15%) require calculation time-steps as short as every 2-3 h. Based on annual median base-flow/storm-flow chemical concentrations, the annual fluxes of ??? 75% of trace elements (e.g. Cu, Pb, Zn), major elements (e.g. Fe, Al), and total P occur in association with suspended sediment; in turn, ??? 90% of the transport of these constituents occur in conjunction with storm-flow. As such, base-flow sediment-associated and dissolved contributions represent relatively insignificant portions of the total annual load. An exception is total N, whose sediment-associated fluxes range from 50% to 60%; even so, storm-related transport typically exceeds 80%. Hence, in urban environments, non-point-source appear to be the dominant contributors to the fluxes of these constituents.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Monitoring urban impacts on suspended sediment, trace element, and nutrient fluxes within the City of Atlanta, Georgia, USA: Program design, methodological considerations, and initial results
Series title:
Hydrological Processes
DOI:
10.1002/hyp.6699
Volume
22
Issue:
10
Year Published:
2008
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Hydrological Processes
First page:
1473
Last page:
1496
Number of Pages:
24