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Application of a Multipurpose Unequal-Probability Stream Survey in the Mid-Atlantic Coastal Plain

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Abstract:A stratified random sample with unequal-probability selection was used to design a multipurpose survey of headwater streams in the Mid-Atlantic Coastal Plain. Objectives for data from the survey include unbiased estimates of regional stream conditions, and adequate coverage of unusual but important environmental settings to support empirical modeling of the factors affecting those conditions. A sample of 175 first-order non-tidal streams was randomly selected for synoptic sampling of water chemistry and benthic and riparian ecology during the late winter and spring of 2000. Twenty-five streams were chosen within each of seven hydrogeologic subregions (strata) that were delineated from physiography and surficial geology. In each subregion, unequal inclusion probabilities were used to provide an approximately even distribution of streams along a gradient of forested to developed (agricultural or urban) land in the contributing watershed. Alternate streams were also selected. Sampling sites on selected streams were located in the field on the basis of accessibility; alternates were included in groups of five in each subregion when field reconnaissance demonstrated that primary streams were inaccessible or otherwise unusable. Despite the rejection and replacement of a considerable number of primary streams during reconnaissance (up to 40 percent in one subregion), the desired land-use distribution was maintained within each hydrogeologic subregion without sacrificing the probabilistic design.
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Citation:Ator, S. W., A. R. Olsen, A. M. Pitchford, and J. M. Denver. Application of a Multipurpose Unequal-Probability Stream Survey in the Mid-Atlantic Coastal Plain. JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION 39(4):873-885, (2003).
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Contact: Chris Siebert - (702) 798-2234 or siebert.christopher@epa.gov
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Division: Environmental Sciences Division
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Branch: Landscape Ecology Branch
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Product Type: Journal
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Published: 08/29/2003
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Related Entries:
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Bullet Item Landscape Indicators for Stream Vulnerability to Pesticides and Toxic Substances
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Last Updated on Monday, October 22, 2007
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