Monitoring statistics.  An important tool for groundwater and soil studies

Schweitzer, Glenn E.; Black, S.C.

doi:10.1021/es00141a001

Cited by 10 publications

(6 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In turn, the statistical method required for spatial analysis will depend upon the type of monitoring and on the characteristics of the groundwater basin studied (Beach 1987). Thus, there is a growing literature that heeds Ward's call, (Nelson and Ward 1981, Pfannkuch 1982, Carrera and others 1984, Schweitzer and Black 1985, Showaher 1985, Rouhani I985, 1986, Ward and others 1986, Cohen and Smiriglio 1987, Loftis and others 1987, Montgomery and others 1987, Meyer and Brilt 1988, Choquette and Katz 1989, among others) including contributions from a growing number of geographers (e.g., Rajagopal 1986, Beach 1987, Hsueh and Rajagopal 1988, Loaiciga 1989, Costanza and others 1992. Beach (1987) reviews this literature extensively.…”

Section: Introductionmentioning

confidence: 99%

Evaluating the effects of spatial monitoring policy on groundwater quality portrayal

Luzzadder–Beach

1995

Environmental Management

View full text Add to dashboard Cite

What size sample is sufficient for spatially sampling ambient groundwater quality? Water quality data are only as spatially accurate as the geographic sampling strategies used to collect them. This research used sequential sampling and regression analysis to evaluate groundwater quality spatial sampling policy changes proposed by California's Department of Water Resources. Iterative or sequential sampling of a hypothetical groundwater basin's water quality produced data sets from sample sizes ranging from 2.8% to 95% coverage of available point sample sites. Contour maps based on these sample data sets were compared to an original (control), mapped hypothetical data set, to determine at which point map information content and pattern portrayal are not improved by increasing sample sizes. Comparing series of contour maps of ground water quality concentration is a common means of evaluating the geographic extent of groundwater quality change.Comparisons included visual inspection of contour maps and statistical tests on digital versions of these map files, including correlation and regression products. This research demonstrated that, clown to about 15% sample site coverage, there is no difference between contour maps produced from the different sampling strategies and the contour map of the original data set.How many groundwater sample sites are necessary to determine and map groundwater quality in a basin? This is not only a statistical question, since it is often more useful to know the geographical distribution of water quality variables than it is to know the mean values of a basin. Careful sampling is necessary to determine the source areas and distribution of pollutants or toxic natural constituents. The goal of this research is to motivate scientists and natural resources managers to consider the effect of sampling designs when designing and implementing groundwater quality monitoring programs and when making decisions based on visual and statistical interpretations of groundwater quality data and water quality contour maps.

show abstract

Section: Introductionmentioning

confidence: 99%

Evaluating the effects of spatial monitoring policy on groundwater quality portrayal

Luzzadder–Beach

1995

Environmental Management

View full text Add to dashboard Cite

show abstract

“…These parameters reflect both the interand intrasampling site dispersion of concentrations. The in situ dispersion can be estimated from the replicate sampling and analysis of the sediments (49,50). For each compound the Student's test can be used to define an interval of concentration encompassing most of the analytical measurements performed at each sampling site.…”

Section: Resultsmentioning

confidence: 99%

Spatial and temporal variance of hydrocarbon pollution data in a coastal river-influenced sedimentary system

Grimalt¹,

Cantón²,

Alonso³

1992

Environ. Sci. Technol.

View full text Add to dashboard Cite

“…The frequency of detection of trace elements and volatile organic compounds in water from the wells was compared between the control area and the urban area (table G-8). A nonparametric comparison, Fisher's exact test, was used to make the comparison (Schweitzer and Black, 1985. ) Of the five trace elements (cadmium, chromium, lead, zinc, and selenium), all but zinc were detected more frequently in the urban area than in the control area.…”

Section: Comparison Of Water Quality Between Control Area and Urban Areamentioning

confidence: 99%

US Geological Survey Toxic Substances Hydrology Program: Proceedings of the technical meeting, Phoenix, Arizona, September 26-30, 1988

Mallard¹

1989

View full text Add to dashboard Cite

In August 1979, the subsurface was contaminated near Bemidji, Minnesota, when a pipeline burst, spilling crude oil on a glacialoutwash aquifer. After cleanup efforts were completed, approximately 400,000 liters of crude oil remained in the aquifer. In 1983, the U.S. Geological Survey began research on the mobilization, transport, and fate of petroleum derivatives at the site. In the 9 years since the spill, petroleum has moved about 30 meters downgradient as a separate fluid phase, constituents dissolved in ground water have moved 200 meters, and vapors through the unsaturated zone have moved 100 meters. Each phase continued to advance during June 1987 through Juty 1988, although the rate of advance of the plume of contaminated water was less than the calculated ground-water velocity. The petroleum source is becoming increasingly viscous, dense, and depleted in volatile compounds. The petroleum derivatives moving with ground water and through the unsaturated zone are being degraded to water, carbon dioxide, and methane. The maximum extent of ground-water contamination eventually may be controlled by the near-equilibrium condition between the rate at which the petroleum is dissolved and transported by ground water and the rate at which it is degraded by microbes. If this hypothesis is confirmed by additional long-term research, it implies that many problems of groundwater contamination by petroleum derivatives might be managed successfully without direct remedial action if the volume of the subsurface affected at the maxium extent of contamination is acceptably small.

show abstract

Monitoring statistics. An important tool for groundwater and soil studies

Cited by 10 publications

References 2 publications

Evaluating the effects of spatial monitoring policy on groundwater quality portrayal

Evaluating the effects of spatial monitoring policy on groundwater quality portrayal

Spatial and temporal variance of hydrocarbon pollution data in a coastal river-influenced sedimentary system

US Geological Survey Toxic Substances Hydrology Program: Proceedings of the technical meeting, Phoenix, Arizona, September 26-30, 1988

Contact Info

Product

Resources

About