GIS‐ASSISTED REGRESSION ANALYSIS TO IDENTIFY SOURCES OF SELENIUM IN STREAMS<sup>1</sup>

See, Randolph B.; Naftz, David L.; Qualls, Charles L.

doi:10.1111/j.1752-1688.1992.tb03997.x

Cited by 10 publications

(13 citation statements)

References 7 publications

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“…As all variables in all years showed a significant positive skewness together with kurtosis it was felt inappropriate to use annual mean values in linear regression analysis versus time. Instead annual median values were employed in regression analysis (See et al, 1992) because they are a superior measure of central tendency and resistant to the effects of outliers, typical of skewed data sets (Sokal and Rohlf, 1969). However, because of the lack of normality in the data a Mann–Whitney test (Hollander and Wolfe, 1999) was used to compare data for 1997 and 2000 rather than the conventional parametric two‐sample t test.…”

Section: Methodsmentioning

confidence: 99%

Halting the Upward Trend in Soluble Phosphorus Transported from a Grassland Catchment

Lennox

Bailey²

2003

J of Env Quality

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An upward trend in soluble reactive phosphorus (SRP) concentrations in Northern Ireland rivers leading to increased eutrophication has been reported for the last two decades. To identify if a similar trend could be observed in land drainage waters SRP and other P fractions were measured weekly from 1989 to 1997 in land drainage from a 9-ha grassland catchment in Northern Ireland that had a mean P surplus applied of 23.4 kg P ha(-1) yr(-1). Regressions of annual median concentrations of P fractions in land drainage waters against time for 1989 through to 1997 showed significant increases of SRP and soluble unreactive phosphorus (SUP) of 2.4 and 1.2 microg P L(-1) yr(-1), respectively. However, the annual flow-weighted concentrations and loads of all P fractions did not show significant increases with time. During the period 1998-2000 a change of management was introduced when only maintenance dressings of P were applied to the catchment according to Ministry of Agriculture, Fisheries and Food guidelines. This resulted in significant reductions in SRP concentrations in 2000 compared with 1997.

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Section: Methodsmentioning

confidence: 99%

Halting the Upward Trend in Soluble Phosphorus Transported from a Grassland Catchment

Lennox

Bailey²

2003

J of Env Quality

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“…These sources are usually underlain by selenium-bearing geologic formations. Historical water-quality data show the highest selenium concentrations within the Kendrick Watershed are found primarily in irrigation waters proximal to shale-derived soils (Natrona County Conservation District, 2005;Erdman, 1989;See et al, 1992;Seiler et al, 1999). More recent water-quality data collected at nonirrigation sites in the project area also had high selenium concentrations, indicating that selenium exceedances are not limited to irrigation lands.…”

Section: Discussionmentioning

confidence: 83%

“…This analysis expands on an earlier study by See et al (1992) that applied a similar methodology of regressing watershed characteristics to predict in-stream selenium concentration. See et al (1992) found that most of the variability in median selenium loads can be explained by the area of irrigated land and the length of irrigation canals.…”

Section: Methodsmentioning

confidence: 93%

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North Platte River Selenium Total Maximum Daily Load Development Using a Geographic Information System Regression Approach

Foreman

Kenner

2012

World Environmental and Water Resources Congress 2012

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The North Platte River Watershed near Casper, Wyoming, has several streams and waterbodies listed as impaired for selenium on the state of Wyoming's 303(d) list, including the North Platte River. The source of selenium in the North Platte River Watershed near Casper is the local geology that consists of cretaceous tertiary shale formations with high levels of selenium. Past assessments of selenium in the watershed have focused on the influence irrigation practices on these cretaceous shales have on selenium concentrations in the river system. The Casper Canal delivers irrigation water from Alcova Reservoir, located approximately 25 miles southwest of Casper, to approximately 24,000 acres of irrigated lands in the CasperAlcova Irrigation District. This project, initiated in 2009 by the Wyoming Department of Environmental Quality (WDEQ), was a Total Maximum Daily Load (TMDL) project for selenium in the North Platte River and four of its major tributaries.To explain variability in the selenium data, a spatial regression approach was used to correlate watershed characteristics to selenium concentrations at several locations in the North Platte River Watershed near Casper. Possible sources were identified as the watershed characteristics with the highest correlation to selenium concentrations. This analysis expanded on an earlier U.S. Geological Survey study that applied a similar methodology of regressing watershed characteristics to predict in-stream selenium concentration. This TMDL project incorporated the regression analysis to aid in allocating the loading to various sources within the watershed and to help guide implementation in the watershed for future projects.It was found that most of the variability in selenium can be explained by the percent of irrigated land, the length of irrigation canals, and the percent of cretaceous shale in each subwatershed. Background levels of selenium from sources other than irrigation practices were also evaluated to determine the ability of the tributary streams to meet the current water-quality criteria. 445

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“…The HRU approach derives segments from the homogeneity of physiographic and geographic parameters. It has been widely applied with geographic information systems (GIS) and remotely sensed data to facilitate hydrological modeling (See et al, 1992;Greene and Cruise, 1995;Chen, 2007Chen, , 2008. Units with similar hydrological response can be grouped by overlying different layers of physiographic information that preserves the heterogeneity of the watershed (Flugel, 1995).…”

Section: Introductionmentioning

confidence: 99%

Hydrological Modeling of Subartic Wetlands: Comparison Between SLURP and WATFLOOD

Jing

Chen

2011

Environmental Engineering Science

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Subarctic wetlands span almost one-sixth of the Canadian wetlands and have been acknowledged as an important ecotone between arctic tundra and boreal forest. Their hydrological complexity is determined by the climatological and physiographical characteristics with regard to the spatiotemporal distribution of water resources. In this study, two semi-distributed hydrological models, SLURP (semi-distributed land use-based runoff processes) and WATFLOOD TM , were employed to understand their effectiveness in modeling the hydrology of subarctic wetlands. Comparisons of their delineation approaches, formulations, parameters, and simulation results indicated that both models were capable of simulating the hydrological processes. However, differences were also observed. Besides their different segment delineation approaches, snowmelt and spring peak flows simulated by SLURP were 4-7 days earlier than those estimated by WATFLOOD because SLURP predefines snowmelt rates as variables, whereas WATFLOOD applies constants in the degree-day method. Due to the lack of considering the existence of permafrost and numerous seasonal ponds, both models tended to underestimate the spring peak flows. Evapotranspiration estimated by the Morton complementary relationship areal evapotranspiration method adopted in SLURP was lower than that calculated by WATFLOOD. Summer runoff only appeared during intense rainfall events, and its concentration was much faster in both models as compared with the observed records, which may be attributed to the variations of permafrost depth, soil water storage capacity, and seasonal pond levels. These findings will be helpful in improving the modeling quality of the two models and understanding the hydrologic features of subarctic wetlands.

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GIS‐ASSISTED REGRESSION ANALYSIS TO IDENTIFY SOURCES OF SELENIUM IN STREAMS¹

Cited by 10 publications

References 7 publications

Halting the Upward Trend in Soluble Phosphorus Transported from a Grassland Catchment

Halting the Upward Trend in Soluble Phosphorus Transported from a Grassland Catchment

North Platte River Selenium Total Maximum Daily Load Development Using a Geographic Information System Regression Approach

Hydrological Modeling of Subartic Wetlands: Comparison Between SLURP and WATFLOOD

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GIS‐ASSISTED REGRESSION ANALYSIS TO IDENTIFY SOURCES OF SELENIUM IN STREAMS1

Cited by 10 publications

References 7 publications

Halting the Upward Trend in Soluble Phosphorus Transported from a Grassland Catchment

Halting the Upward Trend in Soluble Phosphorus Transported from a Grassland Catchment

North Platte River Selenium Total Maximum Daily Load Development Using a Geographic Information System Regression Approach

Hydrological Modeling of Subartic Wetlands: Comparison Between SLURP and WATFLOOD

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GIS‐ASSISTED REGRESSION ANALYSIS TO IDENTIFY SOURCES OF SELENIUM IN STREAMS¹