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Techniques for detecting effects of urban and rural land-use practices on stream-water chemistry in selected watersheds in Texas, Minnesota,and Illinois

Open-File Report 93-130

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Abstract

A discussion is presented of several parametric and nonparametric statistical techniques for detecting trends in water-chemistry data. The need for reducing the effects of natural variability was recognized and accomplished through the use of regression equations. This report describes the use of storm mass-transport data as a means of improving regression relations, thereby reducing data variability. Selected statistical techniques were applied to 1 urban watershed in Texas, 2 urban watersheds in Minnesota, and 3 rural watersheds in Illinois. For the urban watersheds, single- and paired-site data-collection strategies were considered. The paired-site strategy was much more effective than the single-site strategy for detecting trends. For the rural watersheds, none of the selected techniques proved to be effective at identifying trends, primarily because of a small degree of management-practice implementation, potential errors introduced through the estimation of storm mass transport, and small sample sizes. A Monte Carlo sensitivity analysis was used to determine the percent change in chemistry that could be detected for each watershed. In most instances, the use of regressions improved the ability to detect trends. (USGS)

Additional Publication Details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
Techniques for detecting effects of urban and rural land-use practices on stream-water chemistry in selected watersheds in Texas, Minnesota,and Illinois
Series title:
Open-File Report
Series number:
93-130
Edition:
-
Year Published:
1993
Language:
ENGLISH
Publisher:
U.S. Geological Survey ; Books and Open-File Reports [distributor],
Description:
iv, 16 p. :ill. ;28 cm.