web mapping service of natural background values of

Bayerisches Landesamt für Umwelt


Web Mapping Service of Natural Background Values

of Groundwater in Germany

Bernhard Wagner, LfU Bayern


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Project background values of groundwater in Germany

Regional background values of groundwater –

legal requirements

• EU-Water Framework Directive: 2000/60/EG, 2006/118/EG:

achievement of good chemical status of groundwater bodies

• Soil Protection Act (Germany): BBodSchG (1999) (federal),

e.g. BayBodSchG (1999) (provincial)

definition of allowed threshold values of pollutants in groundwater


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Project goals and concept

• Working group "Background values of groundwater": launched by the Geological Surveys of Germany 2005 within the

context of the EU-Water Framework Directive

• Goal: determine background values of groundwater in Germany

and make them available in an interactive internet application

• Reference: upper aquifer

• Data basis: abt. 48.000 groundwater measuring points

• Parameters: anorganic major and trace elements

physicochemical parameters


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Parameters

naturally occurring anorganic elements:

Major elements: Ca, K, Mg, Na, HCO3, SO4, Cl

Trace elements: Br, F, PO4, SIO2, Fe, Mn, Ba, Sr

Ag, Al, As, B, Bi, Cd, Co, Cr, Cu, Hg, Li, Mo, Ni,

Pb, Sb, Se, Sn, T, Tl, U, V, Zn

Physicochemical

parameters: electrical conductivity, pH


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Definition background value

Background value: the upper margin of the concentration of an

element to be expected in the groundwater

of a hydrogeochemical unit under natural

conditions

The background value is defined as the 90th percentile of the normal

distribution of the parameters.

Challenge:

Separation of the background population from geogenic or

anthropogenic anomalies within the data sets (component separation)


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Hydrogeochemical units:

resulting from aggregation of hydrogeological units of the

Hydrogeological Map of Germany 1:200.000 (HÜK200)

Hydrogeological Regions

abt. 1000 hydrogeological units

186 hydrogeochemical units


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Hydrogeochemical units:

resulting from aggregation of hydrogeological units of the

Hydrogeological Map of Germany 1:200.000 (HÜK200)


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Background values and anomalies in the histogram

concentration, classified

freq

uen

cy o

f o

ccu

rren

ce

Background

Anomaly


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From the histogram to the probability net

histogram

sum curve presentation in the

probability net

DIN 53804-1


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Identification and exclusion of anomalies

Standard deviation from median value

99,5% 97,5% 90% 75% 50% 25% 10% 2,5% 0,5%

0,1

1

10

100

1000

-3 -2 -1 0 1 2 3

Measu

red

co

ncen

trati

on

MW

median value

threshold upper anomaly

threshold lower anomaly

no

rmal

dis

trib

uti

on

15,00

1,45

15,00

up

per

an

om

aly

low

er

an

om

aly



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Excel-application for data analysis

steering buttons

statistical evaluation

Probability net

histogram



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Advantages of the probability net

• Quick analysis of data distribution (anomalies, normal-lognormal dist.)

• Optical examination of data set on heterogeneities

• Suitable method for determination of statistical distribution parameters

for the background population

• Applicable to all data sets with at least 10 measured values, therefore

also suitable for units with only few measurements

• In combination with GIS a quick examination of systematic distribution of

anomalies possible (detection of patterns)



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Statistical information of the hydrogeochemical units

Maximum

90%-Quantil

75%-Quantil

Median (entspricht 50%-Quantil)

arithmetisches Mittel

25%-Quantil

Minimum

10%-Quantil

80%der Werte

Ko

nze

ntr

ation

50%der Werte

Statistical measures: 5-, 10-, 25-, 50-, 75-, 90-, 95-percentiles

Minimum

75%-percentile

Median (50%-percentile)

25%-percentile

10%-percentile

50 %

of values

Maximum

90%-percentile

80 %

of values

Me

asu

red

co

nce

ntr

ations


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Presentation of results

• WMS-application in the internet: access from any computer connected to the internet (integration e.g. in GIS or Google-Earth)

http://www.bgr.de/Service/grundwasser/huek200/hgc_p90/

• Subdivision of the element concentration ranges in 5 classes:

– 90-perzentiles of hydrogeochemical units

– point data of measuring points (anonymously and no exact position due to data protection requirements)

• Grey areas: units with insufficient measuring points

• Service online since beginning of 2010


IAH Krakow 2010

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Examples for different parameters:

Sulfate observation points


IAH Krakow 2010

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Sulfate distribution 90-perzentile


IAH Krakow 2010

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Vanadium observation points


IAH Krakow 2010

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Vanadium distribution 90-perzentile


IAH Krakow 2010

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Calcium distribution 90-perzentile


IAH Krakow 2010

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Hydrogencarbonate distribution 90-perzentile


IAH Krakow 2010

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Chloride distribution 90-perzentile


IAH Krakow 2010

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Arsenic distribution 90-perzentile


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Using the WMS in ArcGIS: Example sulfate


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Example: combination of different WMS in ArcGIS


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GeoViewer BGR


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Soil Information System Bavaria


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Benefits of the Web Map Service

• Direct and straightforward availability of data via the internet

• Basis for evaluation of the chemical status of groundwater bodies

• Evaluation of groundwater analyses based on the regional

background values

• Easier identification of groundwater contaminations

• Local specific features of groundwater chemical properties can be

identified through the point data


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Outlook: ongoing works

• Following requirements of the EU-Water Framework Directive, many

additional measurements of groundwater quality have been

performed in the meantime

• Trace elements with larger gaps in the dataset are being re-

evaluated:

As, B, Ba, Cd, Co, Cr, Cu, F, Hg, Mo, Ni, Pb, Sb, Se, Tl, U, V, Zn

• Improvement of usability of the WMS

• Add maps of medians (50-percentiles) adding up to >120 layers

• New WMS with enlarged dataset and new functions shall be available

at the end of the year

web mapping service of natural background values of

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