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Analysis of water quality trends in ...

Law, Neely Leda.

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Analysis of water quality trends in urban-suburban watersheds.

紀錄類型:	書目-電子資源 : Monograph/item
正題名/作者:	Analysis of water quality trends in urban-suburban watersheds./
作者:	Law, Neely Leda.
面頁冊數:	163 p.
附註:	Source: Dissertation Abstracts International, Volume: 65-04, Section: A, page: 1490.
Contained By:	Dissertation Abstracts International65-04A.
標題:	Geography. -
電子資源:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3129754

Analysis of water quality trends in urban-suburban watersheds.
Law, Neely Leda.

Analysis of water quality trends in urban-suburban watersheds. - 163 p.

Source: Dissertation Abstracts International, Volume: 65-04, Section: A, page: 1490.

Thesis (Ph.D.)--The University of North Carolina at Chapel Hill, 2004.

The focus of this research is to better understand how the human component of urban ecosystems, beyond land use, affects the pattern of surface water quality, specifically nitrate. The study site includes a set of nested watersheds that are representative of a land use gradient in Baltimore City and Baltimore County, Maryland. Empirical data, statistical and simulation models were used in combination to analyze how variations in land use land cover, lawn management practices and water resources infrastructure, such as sewers and septic systems, affect the magnitude and pattern of surface water nitrate-N concentrations. It was found that there can be significant variation of nitrate-N concentrations within mixed land use watersheds. The variations are conditioned in part by land use land cover, but also by land management practices and the hydrologic connectivity (e.g. I/I, BMPs, septic plumes) within the watershed. The input of nitrogen from lawn care practices is affected by a socio-ecological feedback system where the input of fertilizer nitrogen was controlled by socio-economic and soil characteristics. Although results of the lawn care survey indicated that fertilizer is a major source of N in urban watersheds, simulation results suggested that its impact on surface water is temporally variable and less significant than septic system effluent. Statistical analyses and model simulations revealed that changes in hydrologic conditions, both daily and seasonally (e.g. runoff, soil moisture conditions) alter the pathways of nitrate delivery to surface water. The change in source areas is attributed to the modified drainage network in both sewered and non-sewered watersheds that create variable patterns in runoff amongst the urban-suburban. Hydrologic disconnectivity between baseflow and surface water during a dry-down period significantly increased the retention of nitrate within the watershed that was subsequently flushed during a wet-up period. This redistribution of sources, sinks and altered hydrologic flowpaths create local conditions that affect water quality. Results suggest that the complexity of such local processes and factors within the small to medium-sized watersheds confounds the land use land cover paradigm of decreasing water quality with an increase in urban development.Subjects--Topical Terms:

524010
Geography.

Analysis of water quality trends in urban-suburban watersheds.
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