web map service for inorganic background values of groundwater in

Bayerisches Landesamt fürUmwelt

WEB MAP SERVICE FOR INORGANIC BACKGROUND VALUES OF GROUNDWATER IN GERMANYB. Wagner, T. Walter


Groundwater chemistry as a result of interacting factors: influences from the surface

underground processes

airpollution

temperature rainfall

weathering mixingprocesses

GW-recharge mining

lithology

land-use

pointsources

chemical composition of groundwater

anthropogene Faktoren

Grundwasserentnahme

groundwater usage

natürliche Faktoren

hydraulic properties

Aquifer-Typus

climate

groundwater abstraction

atmospheric deposition

Ore

bodi

es

geology

natural factors anthropogenic factors

Background Values of Groundwater in Germany


Conceptual model of parameter distribution

factors influencing groundwater chemistry have different ranges and intensities in time and space:

widespread, natural longterm factors will produce a stable equilibrium with definite statistical parameters

Short term anthropogenic influences will act on a more local scale and at a different range of values, natural mineralisations are also limited in space

BACKGROUND

ANOMALY



Overlapping of a normal and an anomalous distribution



histogram and probability plot:



The probability plot as diagnostic and statistical tool



Treatment of censored data



Treatment of values below detection level:0,5% 2,5% 10% 25% 50% 75% 90% 97,5% 99,5%

0,8

1,81,829818802

0,1664171550,1

1

10

100

-3 -2 -1 0 1 2 3

Kupf

er C

u [µ

g/l]

standard deviations from meanupper anomaly normal population lower cut-off valueupper cut-off value 10th and 90th percentiles confidence limits 90%trend normal population

95%: 2,46

90%: 1,83

0%

10%

20%

30%

0,1 1 10 100

empirical distribution of data fitted distribution

Range of data < d.l.

Detection level

Detectionlevel



IAH Krakow 201010

Project goals and concept

• Working group "Background values of groundwater":launched by the Geological Surveys of Germany within the context of the EG-Water Framework Directive

• Goal: determine background values of groundwater in Germanyand illustrate them in a map

• Reference: upper aquifer

• Data basis: abt. 48.000 groundwater measuring points

• Parameters: anorganic major and trace elementsphysicochemical parameters



IAH Krakow 201011

Parameters

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



IAH Krakow 201012

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))



IAH Krakow 201013

Geology of Germany



IAH Krakow 201014

Hydrogeochemical units: resulting from aggregation of hydrogeological units of the hydrogeological map of Germany 1:200.000 (HÜK200)

larger hydrogeological units

abt. 1000 hydrogeological units à

186 hydrogeochemical units



IAH Krakow 201015

Statistical information of the hydrogeochemical units

Maximum

90%-Quantil

75%-Quantil

Median (entspricht 50%-Quantil)

arithmetisches Mittel25%-Quantil

Minimum

10%-Quantil

80%der Werte

Konz

entra

tion

50%der Werte

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



IAH Krakow 201016

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:– 90th percentiles of hydrogeochemical units – point data of measuring points

• hightest class: concentrations above GFS-, TVO- or WHO-limit valueswhere they exist

• grey areas: units with insufficient measuring points



IAH Krakow 201017


Examples for different parameters:

Sulphate observation points


IAH Krakow 201018


Sulphate distribution 90th percentile



IAH Krakow 201019


Vanadium observation points



IAH Krakow 201020


Vanadium distribution 90th percentile



IAH Krakow 201021

Example sulfate



IAH Krakow 201022

Example: combination of different WMS in ArcGIS



IAH Krakow 201023

Benefits

• 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



IAH Krakow 201024

Further plans

• Following requirements of the EG-WFD, many additional measurements have been performed in the meantime

• trace elements with larger gaps in the dataset will be re-evaluated:antimon, cobalt, molybdenum, selen, thallium, uranium, vanadium

• WMS with enlarged dataset shall be available at the end of the year


web map service for inorganic background values of groundwater in

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