PATTERNS OF WATERSHED URBANIZATION AND IMPACTS ON WATER QUALITY1

Authors

  • Melissa Vernon Carle,

    1. Respectively, Wetlands Specialist, North Carolina Division of Coastal Management, Mail Service Center 1638, Raleigh, North Carolina 27669 (formerly Research Associate, Duke University); Assistant Professor of the Practice of Landscape Ecology, Nicholas School of the Environment and Earth Sciences, Duke University, Box 90328, Durham, North Carolina 27708; and Associate Professor, Department of Environmental Health Sciences, Arnold School of Public Health, University of South Carolina, Columbia, South Carolina 29208 (Email/Carle: melissa.carle@ncmail.net).
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  • Patrick N. Halpin,

    1. Respectively, Wetlands Specialist, North Carolina Division of Coastal Management, Mail Service Center 1638, Raleigh, North Carolina 27669 (formerly Research Associate, Duke University); Assistant Professor of the Practice of Landscape Ecology, Nicholas School of the Environment and Earth Sciences, Duke University, Box 90328, Durham, North Carolina 27708; and Associate Professor, Department of Environmental Health Sciences, Arnold School of Public Health, University of South Carolina, Columbia, South Carolina 29208 (Email/Carle: melissa.carle@ncmail.net).
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  • Craig A. Stow

    1. Respectively, Wetlands Specialist, North Carolina Division of Coastal Management, Mail Service Center 1638, Raleigh, North Carolina 27669 (formerly Research Associate, Duke University); Assistant Professor of the Practice of Landscape Ecology, Nicholas School of the Environment and Earth Sciences, Duke University, Box 90328, Durham, North Carolina 27708; and Associate Professor, Department of Environmental Health Sciences, Arnold School of Public Health, University of South Carolina, Columbia, South Carolina 29208 (Email/Carle: melissa.carle@ncmail.net).
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  • 1

    Paper No. 04044 of the Journal of the American Water Resources Association (JAWRA) (Copyright © 2005). Discussions are open until December 1,2005.

Abstract

ABSTRACT: Urban runoff contributes to nonpoint source pollution, but there is little understanding of the way that pattern and extent of urbanization contributes to this problem. Indicators of type and density of urbanization and access to municipal services were examined in six urban watersheds in Durham, North Carolina. Principal components analysis (PCA) was used to identify patterns in the distribution of these variables across the urban landscape. While spatial variation in urban environments is not perfectly captured by any one variable, the results suggest that most of the variation can be explained using several variables related to the extent and distribution of urban development. Multiple linear regression models were fit to relate these urbanization indicators to total phosphorus, total kjeldahl nitrogen, total suspended solids, and fecal coliforms. Development density was correlated to decreased water quality in each of the models. Indicators of urbanization type such as the house age, amount of contiguous impervious surface, and stormwater connectivity explained additional variation. In the nutrient models, access to city services was also an important factor. The results indicate that while urbanization density is important in predicting water quality, indicators of urbanization type and access to city services help explain additional variation in the models.

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