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dc.contributor.authorPebesma EJ
dc.date.accessioned2012-12-12T15:19:48Z
dc.date.available2012-12-12T15:19:48Z
dc.date.issued1992-11-30
dc.identifier721801002
dc.identifier.urihttp://hdl.handle.net/10029/257210
dc.description.abstractAbstract niet beschikbaar
dc.description.abstractChloride and nitrate concentrations in groundwater are mapped on a national scale using classification, point kriging, stratified point kriging and stratified block kriging. A soil map aggregated to six main soil types (peat, sand, marine clay, fluvial clay, old clay and loam) is used as classification criterion. Zinc and cadmium concentrations in groundwater are mapped on a national scale using stratified block kriging. The results are presented as 95% confidence intervals of the predictions. When spatial dependence between measurements is observed, kriging interpolation results in more spatially differentiated maps than those obtained by classification. For mapping on a national scale block kriging seems more appropriate than point kriging because of the large uncertainties that result from the latter. Stratification preceding kriging is needed because of important differences between the strata. High concentrations along the coast characterise the chloride concentration maps. Block averages indicate a difference between high sand areas with chloride concentrations below 50 mg/l and areas near the coast with chloride concentrations above 50 mg/l. All methods used for mapping nitrate produce overlapping confidence intervals. The upper side of the confidence intervals show high tendencies on areas with high sand soils. In the provinces Noord-Brabant and Limburg (South East Holland) some areas have block averaged zinc and cadmium concentrations higher than the background value (a-level). The confidence intervals do not exclude b- or c-levels (signal and danger levels, respectively).
dc.description.sponsorshipRIVM
dc.format.extent71 p
dc.language.isonl
dc.relation.ispartofRIVM Rapport 721801002
dc.relation.urlhttp://www.rivm.nl/bibliotheek/rapporten/721801002.html
dc.subject13nl
dc.subjectgrondwaternl
dc.subjectkwaliteitnl
dc.subjectgrondsoortnl
dc.subjectkaartnl
dc.subjectchloridenl
dc.subjectnitraatnl
dc.subjectzinknl
dc.subjectcadmiumnl
dc.subjectclassificatienl
dc.subjectconcentratienl
dc.subject92-4nl
dc.subjectinterpolationnl
dc.subjectinterpolatienl
dc.subjectgroundwateren
dc.subjectqualityen
dc.subjectsoil typesen
dc.subjectmapen
dc.subjectchloridesen
dc.subjectnitratesen
dc.subjectzincen
dc.subjectcadmiumen
dc.subjectclassificationen
dc.subjectconcentrationen
dc.titleEen landelijk beeld van grondwaterkwaliteitsvariabelen. Deel 1: Een onderzoek naar interpolatiemethodennl
dc.title.alternativeNational map of groundwater quality parameters. Part 1: Interpolation methodsen
dc.typeReport
dc.date.updated2012-12-12T15:19:49Z
html.description.abstractAbstract niet beschikbaar
html.description.abstractChloride and nitrate concentrations in groundwater are mapped on a national scale using classification, point kriging, stratified point kriging and stratified block kriging. A soil map aggregated to six main soil types (peat, sand, marine clay, fluvial clay, old clay and loam) is used as classification criterion. Zinc and cadmium concentrations in groundwater are mapped on a national scale using stratified block kriging. The results are presented as 95% confidence intervals of the predictions. When spatial dependence between measurements is observed, kriging interpolation results in more spatially differentiated maps than those obtained by classification. For mapping on a national scale block kriging seems more appropriate than point kriging because of the large uncertainties that result from the latter. Stratification preceding kriging is needed because of important differences between the strata. High concentrations along the coast characterise the chloride concentration maps. Block averages indicate a difference between high sand areas with chloride concentrations below 50 mg/l and areas near the coast with chloride concentrations above 50 mg/l. All methods used for mapping nitrate produce overlapping confidence intervals. The upper side of the confidence intervals show high tendencies on areas with high sand soils. In the provinces Noord-Brabant and Limburg (South East Holland) some areas have block averaged zinc and cadmium concentrations higher than the background value (a-level). The confidence intervals do not exclude b- or c-levels (signal and danger levels, respectively).


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