Geological Survey of Denmark and GreenlandDanish Ministry of Energy, Utilities and Climate

Groundwater monitoring and modelling

in Denmark

Bertel NilssonLærke Thorling

Groundwater monitoring in DK

National groundwater monitoring since 1988

Waterworks wells monitoring since 1986

All data are open to the public and reported every year. Focus on groundwater quality

Groundwater modelling in DK

Long time experience with numerical modelling. National groundwater model since ca. 2000

Focus on groundwater quantity

Take homeMESSAGES

Background

• Groundwater constitutes 100 % of the drinking water resource in Denmark• Groundwater is heavily exploited in some areas

– Drinking water to the east -Irrigation to the west (dry years only)

• 63 % of all Denmark is cultivated agricultural areas• Groundwater quality and quantity crucial for surface waters

History

– 1950: First national groundwater table monitoring programme

– 1988: The national groundwater monitoring programme initiated, as part of an integrated national water monitoring programme

– 2004: The national groundwater table monitoring programme is integrated in the overall monitoring programme

– 2007: The Water Framework Directive initiates a change in monitoring strategy and redesign of the monitoring network

What is Groundwater monitoring?

Groundwater monitoring collects data of relevance for policy and management issues in the water sector. Special focus on establishment of time series, mapping secondary

Groundwater quantity

Groundwater table soundings

Water abstractions

National hydrological model

Groundwater quality

Groundwater samples from

• Monitoring wells

• Abstraction wells at all water works wells in DK

Point source data are handled separately (in DK)

No data from private drinking water wells or drinkingwaterused to asses status or trend.

Researachand

development

•Methodology

• Interpretation

•Dating

•Water cycle

•Analytical methods

•Modeling

Mangagement

Policy

•EU directives

•European Env. Agency

•Municipalities and EPA

•Waterplans other planning

•Efficiency of measures

• Inspection of water works

Dissemination

•Yearly reports

•Thematic reports

• Intercalibration

•Lectures and talks

•Articles

•Cooperation EPA, EU etc.

GroundwaterMonitoring

Monitoring of groundwater in Denmark

What Waterworks Groundwater

monitoring

Pesticides

Leaching (PLAP)

Point sources

Where Abstraction

wells

Monitoring

wells

Monitoring

wells

Drain

Suction cups

Monitoring

wells

(permanent

and temporal)

Abstraction

wells

Why Drinking

water

NOVANA -

Water Plans (EU)

License for

pesticides

Old Point

Pollution

Who Waterworks EPA-nature/

GEUS

GEUS/AU/

EPA-

environment

Regions

How many > 6.000 700-800/year

(~ 1500)

5 areas >15.000 plots

? Pesticides ?

Reporting GEUS GEUS GEUS/AU Regions/

Consultants

Flow of Groundwater Monitoring Data

Environmental Agency/

Water Works

Laboratorium

Laboratorium

GEUS

GEUS

Environmental Agency

Minister/Parliament

EU Commission + EEA

Municipalities etc.

Sampling & field measurements (Standards)

Chemical analysis (ISO- standards)

Data, upload to databases JUPITER, (code system)

Interpretation (Reporting+ data to EEA)

Knowledge

Political evaluation

Political reaction/legislation

Political reaction/legislation

Implementation in administration

GEUS and Groundwater monitoring in DK

• The national groundwater monitoring programme is conducted by EPA and GEUS in cooperation.

• EPA sets the political and economical framework

• GEUS sets the Technical and scientific framework, through manuals and technical guidelines (expertise and datacentre)

• EPA is responsible for collection of samples, contact to laboratories and primary data management

• GEUS is responsible for the yearly reporting of data to the political system and the public.

• GEUS host the database JUPITER, with all relevant groundwater data

Need to have representative data:

Monitoring strategy

1988-2006:Principle: Know the details in 72 areasand generalise to national levelUnderstand the local dynamicsUse it globalAll monitoring points same parameters and frequency

2007:Principle: WFD demands monitoring fitting the approx. 400 groundwater bodiesMore distributed monitoring network under establishmentParameters and frequency according to risk

Difficult to stick to just one monitoring strategy in a

changing political environment over almost 30 years.

GeographicGeologicalgeochemicalLand use and groundwater in risk.

Relevant choice of parametersRelevant frequencyDesign of monitoring wells

Present DesignDanish Groundwater Monitoring sites

• Monitoring in 65 clustered areas of 5-50 km2

each with 20-25 wells and 1 m screen. (700 samples/year)

• Additional monitoring in groundwater bodies at risk (140 samples/year)

• Multilevel monitoring in 5 deep groundwater well (4x80 samples every 3. year)

• Detailed monitoring of surface near groundwater in 5 small agricultural catchments (6x100 samples/year)

• A total of 1600-2000 monitoring points

• One water sample: up to 97 parameters: 26 main elements, 14 heavy metals, 23 organic micro-pollutants, and 34 pesticides

Methodologies and tools

Field work/ Practical work

• Water sampling and drilling new wells

• Traditional hydrogeological field work

• Database development and handling of data

Incorporation of state of art scientific work

• 5D conceptual framework for data interpretation

• All authors in reporting have their theme as scientific working field

• Monitoring groundwater effect on surfacewater/dependent ecosystems

• Cooperation at a EU level (CIS for WFD)

• Cooperation with EEA

• Technical guidance

• Field work, sampling, sounding etc.

• Data management, database work

Depths of monitoring wells

Depth of new sampling points m b.s.

Data available for interpretation

Number of monitoring points Number of nitrate samples

Number of pesticide sampes Number of arsenic samples

The annual report

• Theme authors with expertise in relevant subject

• Same paradigm for every 6 year program period

• Target groups : Danish parliament, EPA, Waterworks, NGO etc.

• Reporting is coordinated with other environmental monitoring programmes

• Only electronic reporting

• Only national reporting, no regional

• Published every year since 1989

• Next issue 3. Dec. 2015 on 2014 data

Thorling et al, 2015, report

Main topics of the Report

• The monitoring network, goals, legal framework and adjustments

• Groundwater Age, Hydrogeology : relevant Background Knowledge

• Nitrate

• Phosphorous

• Redox-wells

• Organic Micro pollutants

• Trace elements

• Pesticides

• Water abstraction

• Groundwater table

• NOVANA-model

Prerequisite for monitoring strategy and interpretation of Chemical state, Trend and Dynamics

Every sample represents a 5D point: (x,y,z,tr,ts).(x,y,z) the location of the filter, tr the time of groundwater recharge, (period)ts the time of sampling.

This statement can easily be said, The huge implications are to often ignored

5D understanding of groundwater quality:

CFC and 3H/3He datingSF6 tested not useful14C not relevant

Not all monitoring points can be dated due to practical issues

Dating of groundwater

Thorling et al, 2015, report

Conceptual modelsgeochemistry – and hydro-geology

Source: Jørgensen & Stockmarr 2009

West East/NorthEast/South

Groundwater table

Groundwater table

Acidification cline

Acidification cline

Redox cline

Redox cline

No clear acidification- nor redox- cline

clay

clay

limestone

Conceptual models are the Basic of all monitoring strategy

How to understand the vulnerability of groundwater

towards nitrate and pesticides

What is the state and trends in the nitrate content for groundwater?

Simple question, many possible answers.

Indicators: Standard figures Monitoring data.

What is the Status and trends of the nitrate content in groundwater used for drinking water ?

Simple question, clearer answerbut No consideration to abstracted amounts only pr. well.

Is there karst in Denmark ?

Bertel Nilsson

(bn@geus.dk)

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