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Contract n° SSPI-2004-006538

BR B R ID I D G G E E

B B a a c c k k g g r r o o u u n n d d c c R R i i t t e e r r i i a a f f o o r r t t h h e e I I d d e e n n t t i i f f i i c c a a t t i i o o n n o o f f G G ro r o un u n d d wa w at t er e r t t h h re r es sh ho o l l ds d s

Research for Policy Support

D10: Impact of hydrogeological conditions on pollutant behaviour in groundwater and related ecosystems.

Volume 1

Due date of deliverable: March 2006 Actual submission date: May 2006

Start date of the project: 1^st January 2005 Duration: 2 years Organisation name of lead contractor for this deliverable: BRGM

Project co-funded by the European Commission within the Sixth Framework Programme (2002-2006)

Dissimination level PU Public

PP Restricted to other programme participants (including the Commission Services) RE Restricted to a group specified by the consortium (including the Commission

Services)

CO Confidential, only for members of the consortium (including the Commission Services)

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D10 : Hydrogeological conditions - volume 1

Deliverable D10 3 / 158

Preface

This report is a deliverable (deliverable D10) of the BRIDGE project, a specific targeted research project (STREP) of the 6^th EU RTD Framework Programme belonging to the Scientific Support Policies Priority. In particular, it is the final deliverable of Workpackage 2 (WP2) “Study of groundwater characteristics”. Dealing with the impact of hydro-geological conditions on pollutant behaviour in groundwater and related ecosystems, this report aims to synthesise the current state of the art of the knowledge throughout Europe. Expert hydrogeologists from different European countries and associated countries contributed to this synthesis through preparation of some sections, replies to questionnaires or active participation in a workshop that took place in Orléans (France). This report has a twofold objective: In a first step it provides part of the information necessary to develop recommendations on a methodology and criteria for an European approach on how to establish environmental thresholds for groundwater bodies. In a later step the same information will be useful for the application of methodology.

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General Content

Volume 1

Chapter 1: Introduction

Chapter 2: Techniques used to collect and process the data Chapter 3: Methodologies used for GWB delineation

Introduction General comment

Delineation of groundwater bodies Aquifer Typology

Interaction with surface waters Assessment of pressures Assessment of vulnerability Risk assessment

Open questions Concluding Remarks References of chapter 3

Chapter 4: Concepts for characterisation of aquifer regarding transport and attenuation of pollutants

Generalities

Typology of aquifers

Characterisation of attenuation between source of pollution and receptor Chapter 5: Hydrogeological processes

Importance of aquifers in the context of the WFD Concept of the aquifer control on pollutants

Attenuation of the pollutants according to aquifer typology

Synthesis and perspective of use of information on hydrogeological processes Appendices: in a separate volume

Chapter 6:Natural Background Levels. State of the art and review of existing methodologies

Introduction

Methodologies to determine the natural background level State of the art on natural background levels

Conclusions References

Appendices: in a separate volume

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6 / 158 Deliverable D10

Volume 2

Chapter 7: Groundwater/surface water interactions Introduction

Aim

Types of surface water systems Chemical/substance concerns

Processes and controls at catchment scale Processes and controls at local scale Discussion

Conclusions References

Chapter 8: Groundwater/dependant terrestrial ecosystems interactions Introduction

Aim

Types of water dependent terrestrial ecosystems

Linking landscape location and water transfer mechanisms

Processes and controls on the groundwater system and the GWDTE.

Chemical /substance concerns Review of methods

Discussion Conclusions

Volume 3

Chapter 9: Impact of quantitative alteration on groundwater quality What means change of quantitative status? Synthesis

Quantity related aquifer responses and triggered processes with impact on groundwater quality

Matrix Actions/quantity impact/triggered processes/quality parameter influenced Assessment of quantitative impacts on quality

Annex Task 2.3 partnerships: contribution of each partner

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Content of Volume 1

Chapter 1 - Introduction... 11

Chapter 2 - Techniques used to collect and process the data... 15

Chapter 3 - Methodologies used for GWB delineation... 19

3.1. Introduction ... 21

3.2. General comment ... 21

3.3. Delineation of groundwater bodies ... 22

3.4. Aquifer classification ... 22

3.5. Interaction with surface waters ... 26

3.5.1. General remarks ... 26

3.5.2. Specific comments on responses ... 26

3.6. Assessment of pressures... 27

3.7. Assessment of vulnerability ... 27

3.8. Risk assessment... 30

3.8.1. General remarks ... 30

3.8.2. Methodology ... 30

3.8.3. Preliminary evaluation of aquifers being at risk ... 34

3.9. Open questions... 34

3.10. Concluding remarks ... 34

3.10.1. Definition of the terms... 34

3.10.2. Current state of RBDs and GWBs ... 35

3.10.3. Typology of GWBs... 35

3.10.4. Numbers and dimensions of RBDs... 35

3.10.5. Percentage of surface of the country covered by the GWB... 35

3.10.6. Numbers and dimensions of the GWB ... 35

3.10.7.Assessment of risk not to reach good status of environmental objectives in 2015 ... 36

3.11. References ... 38

Chapter 4 - Concepts for characterisation of aquifer regarding transport and fate of pollutants ... 47

4.1. Generalities... 49

4.2. Typology for hydrogeochemical characterisation of aquifers... 49

4.3. Characterisation of attenuation between source of pollution and receptor ... 51

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Chapter 5 - Hydrogeological processes... 55

5.1. Importance of aquifers in the context of the WFD... 58

5.2. Concept of the aquifer control on pollutants ... 59

5.2.1. General characteristics influencing both the flow system and physico-chemical processes ... 60

5.2.2. Residence time ... 61

5.2.3. Flow processes – attenuation by dilution... 66

5.2.4. Physico-bio-chemical attenuation in aquifers ... 68

5.2.5. Hydrogeochemical background ... 70

5.3. Aquifer typology and attenuation of pollutants ... 70

5.3.1. Principle and objectives of the typology... 70

5.3.2. Sandstones - siltstones aquifers... 71

5.3.3. Sands and gravels aquifers ... 73

5.3.4. Limestones (karstic/non karstic) aquifers ... 76

5.3.5. Chalk aquifers... 78

5.3.6. Schists and Shales aquifers ... 79

5.3.7. Crystalline aquifers ... 80

5.3.8. Volcanic rocks... 81

Chapter 6 - Natural background levels. State of the art and review of existing methodologies ... 85

6.1. Introduction ... 87

6.2. Approaches to determine Natural Background Levels... 88

6.2.1. Main approaches ... 88

6.2.2. National approaches (FR, D, BL, LT)... 89

6.2.3. Local scale approaches (UK, DK, BL-Flanders, EE, NL, HU, PT) ... 95

6.2.4. The Baseline project ... 97

6.2.5. Conclusion ... 99

6.3. Typology of aquifers ... 99

6.3.1. Description of the typology... 99

6.3.2. Approach to define the “typical natural chemical composition” of each type of aquifer ... 100

6.4. Natural Background Levels in Limestones aquifers... 102

6.4.1. Major elements ... 102

6.4.2. Trace elements ... 105

6.5. Natural background levels in chalk aquifers ... 111

6.6. Natural background levels in sands and gravels aquifers... 113

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6.7. Natural background levels of sandstones aquifers ... 120

6.8. Natural background levels in clayey and marly aquifers... 125

6.9. Natural background levels in crystalline basement rocks aquifers ... 125

6.10. Natural background levels in schists and shales aquifers... 130

6.11. Natural background levels in volcanic aquifers ... 130

6.12. Synthesis... 132

6.13. Saline influence... 134

6.13.1 Salt water... 134

6.13.2. Mixing of salt water with fresh water... 141

6.13.3. Tools for detecting sources of salinization... 142

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Chapter 1 Introduction

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The future European Groundwater Directive, a draft proposal of which has been adopted by the Commission in its final form on January 23 2006¹ is a daughter directive of the Water Framework Directive (2000/60/EC). It represents a comprehensive piece of legislation that will set out clear quality objectives for all groundwaters in Europe. Criteria for the assessment of the chemical status of groundwater are partly based on existing Community quality standards (nitrates, pesticides and biocides) but Member States are required to identify pollutants and threshold values that are representative of groundwater bodies found as being at risk, in accordance with the analysis of pressures and impacts carried out under the WFD.

In the light of the above, the BRIDGE project, EC 6^th Framework Programme project, belonging to the Scientific Support policies priority, has for main objective to derive a plausible general approach, how to structure relevant criteria appropriately with the aim to set representative groundwater threshold values at national river basin district or groundwater body level in a scientifically sound way . This report is a deliverable of the BRIDGE project, prepared to gather part of scientific outputs which could be used to set out thresholds values for pollutants within groundwater. Its aim consists in sharing knowledge on groundwater body/aquifer characteristics of relevance regarding pollutants behaviour and discussed within the frame of Workpackage 2 “Study of groundwater characteristics“ of the project. It is the hydrogeological counterpart of Workpage 1 focusing on geochemistry and pollutants properties.

The present document summarises key elements of groundwater body/aquifer characterisation relevant to pollutants behaviour as described and discussed by partners from 16 European and associated countries (Austria, Belgium, Bulgaria, Denmark, Estonia, Finland, France, Germany, Hungary, Italy, Lithuania, the Netherlands, Poland, Portugal, Spain and United Kingdom).

This report synthesizes partners contribution within the frame of WP2 and comprises 9 Chapters. After this introduction, Chapter 2 presents the approach followed to collect all data on groundwater bodies’ characteristics. Chapter 3 briefly points out the broad range of approaches adopted by Member States delineation and characterisation of groundwater bodies. Chapter 4 sets keys elements for characterizing aquifer with respect to pollutant transport and attenuation. Chapter 5 describes the properties of different European hydrogeological settings with regards to geochemical properties of pollutants. Chapter 6 addresses the methodologies developed within Member state for determination of Natural Background levels of chemical elements within groundwater with a discussion of the results obtained at abovementioned European hydrogeological settings. One key purpose of the WFD being to prevent further deterioration and to protect and enhance the status of aquatic ecosystems, and with regard to their water needs, terrestrial ecosystems and wetlands directly depending on the aquatic ecosystems, chapters 7 and 8 deal with the links between groundwater and surface water and dependent terrestrial ecosystems. Finally, Chapter 9 is devoted to the impact on groundwater quality of changes in groundwater quantitative status.

1 COM(2003)550

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Chapter 2 Techniques used to collect and process the data

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In view of the important number of partners (18) involved within WP2; questionnaires were largely used to collect available scientific data. Such a way enabled to collect data from a wide variety of hydrogeological settings so as provided description is representative of European aquifers.

Firstly, a general questionnaire was intended to identify the current knowledge and any information gaps that must be addressed within the WP2 and record specific interests and capabilities of partners.

This first questionnaire was composed of three types of questions:

- Questions related to available information in countries about the processes for delineation and initial characterisation of groundwater bodies;

- Questions about the experience of partner’s group;

- Questions related more explicitly to the work to be conducted by partners within WP2.

This questionnaire was sent to all partners involved within WP2, who are representatives from 14 countries (Austria, Belgium, Bulgaria, Denmark, France, Estonia, Germany, Hungary, Italy, The Netherlands, Poland, Portugal, Spain and United Kingdom). Additionally, responses to questions related to available information within countries about processes for delineation and initial characterisation of groundwater bodies were delivered by 2 additional countries (Finland and Lithuania). Replies to first part of questionnaire cause writing of chapter 3. Answers to other questions serve as a basis for elaboration of content of chapters 5 to 9. Actually, this questionnaire was followed by 3 more detailed questionnaires.

1. A questionnaire on Natural Background Level (NBL) including questions about:

- Methodologies developed within countries or at case study scale to determine NBL,

- Main results obtained on selected aquifer by applying previously described methodologies (Identification of major and trace elements with high concentrations, with main characteristics of concerned aquifer and hydrogeological settings.

Replies cause writing of Chapter 6 which was discussed and amended by the partners during lateral discussion (via e-mail) and during a special meeting held during WP2 workshop of September in Orléans).

13 Partners, representatives from 11 countries (Belgium, Bulgaria, Germany, Denmark, France, Estonia, Hungary, Lithuania, The Netherlands, Poland and United Kingdom) contributed to this chapter.

2. A questionnaire on contribution of groundwater to surface water and groundwater dependent ecosystems, including questions about:

- Methods or estimating flow contribution of groundwater to surface water or GW dependent ecosystems,

- Methods for estimating the attenuation of pollutants at the groundwater/surface water interface,

- Examples of application within catchments.

Replies cause writing of both chapters 7 and 8, which were discussed and amended among partners via e-mail and though WP2 Workshop.

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Partners involved within this activity are originally from 11 countries (Austria, Bulgaria, Germany, Denmark, Estonia, France, Hungary, Italy, Poland, Portugal, United Kingdom).

3. A questionnaire on pollutant attenuation capabilities of European aquifers, including questions on:

- Hydraulic/hydrogeologic characteristics with a potential impact on dilution of pollutants, - Characteristics of aquifers having an impact on physico/bio-geochemical attenuation (like

precipitation, adsorption, degradation…).

Examples from 9 countries (Belgium, Estonia, France, Germany, Hungary, Italy, Portugal, Spain and United Kingdom) have been provided by partners. These contributions gave rise to chapter 5. However, questionnaire forms were rather late, after September meeting, and consolidated version of chapter has not been discussed and amended by partners. It is expected for D10 to be produced by March 2006.

Chapter 9 dealing with impact of quantitative alteration of groundwater status on groundwater quality involves a more restricted number of partners than other activities (actually 7 countries: Belgium, Estonia, France, Spain, Poland, Portugal, and United Kingdom).

Consequently, work has been structured in a different way. First, partners agreed on a list of typical situations where change of quantitative status may impact qualitative status (both human induced changes and natural/hydroclimatic changes). Secondly, each partners took in charge one or several of these typical situation and produce a description of relation between quantitative and qualitative status changes as well as the methods for detecting these relations

For each of chapters 6 to 9, devoted to synthesis of scientific knowledge, the contents is partly related to partners activities/case studies but also include relevant recent literature, although the topics being much too vast to achieve an exhaustive literature review, only some significant references are cited.

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Chapter 3 Methodologies used for GWB delineation

M. Normand, A. Blum, H. Pauwels, S. Urban (BRGM) Zoltán Simonffy (BME)

Ph. Meus (ULG)

Carlos Martínez Navarrete, José Antonio de la Orden Gómez, Juan Grima Olmedo (IGME) Stanislaw Witczak (DHWP/AGP)

Sophie Vermooten, Jasper Griffioen (TNO) Kestutis Kadunas, Rytis Giedraitis (LGT)

Frank Wendland (FZ-Jülich), Johann-Gerhard Fritsche (HLUG)

Rüdiger Wolter (UBA-D) Andres Marandi (UT) Alwyn Hart, Jan Hookey (EA)

Klaus Hinsby (GEUS), Mette Dahl (GEUS), Kim Dahlstrom (Danish EPA) Martin Skriver (Danish EPA), Per Rasmussen (GEUS)

Andreas Scheidleder, Karin Weber, Arno Aschauer (UBA-A) Rossitza Gorova (EEA)

Gustafsson Juhani (SYKE)

Marleen Coetsiers, Kristine Walraevens (LAGH-UGent) With the contribution from

Vincent Fitzsimons (SEPA-Scotland)

Petra Snellings, Marleen Van Damme (AMINAL-Flanders)

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3.1. Introduction

This chapter summarises and comments responses obtained through questions related to available information about characteristics of groundwater bodies, the way they are delineated and their initial characterisation in each country, questions which were included in the first questionnaire sent to partners.

This questionnaire was sent to all partners involved in WP2, representing 14 countries (Austria, Belgium, Bulgaria, Denmark, France, Estonia, Germany, Hungary, Italy, The Netherlands, Poland, Portugal, Spain and United Kingdom). Some countries have sent several responses separately according to their regional structure: Great Britain (England &

Wales, Scotland) and Belgium (Flanders, Wallonia).

3.2. General comment

The questionnaire content has been detailed within D8. Most questionnaires have been – partly or totally – filled out with more or less details. The responses are showing a large diversity.

Of course such basic information as numbers of district and, in a broad sense, the number of groundwater bodies is reflecting the situation of each of the countries. But issues like delineation of groundwater bodies, typologies, classifications and methodologies are showing a wide range of approaches.

The purpose of this report is not to describe the specific way of each country: the feedbacks are only summarising some points and the writers mostly indicate background national studies concerning particular issues. Taking into account all information contained in these documents would go beyond of the scope of this report.

The questionnaire is intended to identify the current knowledge and any information gaps.

Results are summarised in two sections:

- Similarities and differences between the countries for some key points;

- List of open points.

These similarities and differences are regrouped and presented in table form. The text describing each national approach is nearly the same than the original text in the questionnaire responses in order to reduce interpretation errors.

It should be noticed that the use of this kind of classification is not done in an exclusive manner.

For example, Finland and England & Wales are associated as countries using a “water abstraction” based classification of groundwater bodies. This doesn’t mean that:

- Other characteristics of groundwater bodies are less relevant for the approach of both countries;

- “Water abstraction” couldn’t play an important role for the delineation or the typology for the other countries.

It is only meaning that the both questionnaire responses are emphasising this point.

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Otherwise, important issues like Groundwater Monitoring could not be treated because most of the responses weren’t detailed enough to try a serious comparison.

3.3. Delineation of groundwater bodies

The delineation of the groundwater bodies has been treated by all countries taking into account the hydrographical limits, the hydrogeological parameters and - depending on the countries - the water use.

A few particular points should however been noticed:

- Some countries like France and Austria indicate that the whole territory has been assigned to be covered by more or less shallow groundwater bodies. On the contrary in the case of Finland, the total surface of the delineated groundwater bodies covers only 4.1% of the whole territory;

- Belgium (Flanders), Estonia and Lithuania are indicating that main groundwater systems or bodies are divided in sub-units;

- Bulgaria is divided in 4 river basin directorates, but at the same time in 3 hydrogeological districts.

- Because of the geographical position of Hungary, more than half of the water bodies are partly delineated by the country borders. However they belong to only 1 River basin district.

The Netherlands indicate a classification of groundwater bodies respectively on national (type 1) and in regional (type 2) levels.

3.4. Aquifer classification

The aquifer typology has been treated differently. We can broadly define two groups of countries referring to the most important classification criteria:

- Water abstraction based classification (England and Wales, Finland);

- Hydrogeology based classification (the others countries).

The classification referring to water abstraction has been treated as follows:

Countries Classification

Finland

Class I holds areas important for water supply. From these areas water is extracted and is used by water works which supply at least to 10 or more households (approximately 50 persons). Class II holds areas suitable for water supply. These aquifers are suitable for water supply, but for the time being, the areas are needed neither for the municipal water supply nor for households in the sparsely populated areas. Class III holds other groundwater areas, which need further studies to find out the suitability of the area for water supply.

United Kingdom (England and Wales)

Principal aquifers – those with significant resources which need to be managed through abstraction licensing within a Catchment Abstraction Management Strategy (CAMS) in order to prevent over-exploitation, or those with a significant role in sustaining groundwater dependent ecosystems.

Secondary aquifers – which also have significant resources but with hydraulic properties which limit over-exploitation. These aquifers would not normally warrant special consideration for CAMS but may still support important abstractions and dependent ecosystems which may be subject to risks associated with pollution pressures.

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Unproductive Strata – mostly limited to Tertiary and Jurassic Clays (e.g. London, Oxford, Kimmeridge Clays), which are generally unable to support abstractions greater than 10 m³/d, are unlikely to provide significant baseflow or wetland discharges, and will be considered as ‘not at risk’ without further analysis.

A fourth aquifer type – significant drift aquifer has been defined and delineated from a series of workshops at regional level to show areas where significant groundwater resources occur within the drift overlying unproductive strata.

Belgium (Flanders)

Aquifer classification: an official HCOV code exists. This numerical code forms the standard hydrogeological code for the Flemish subsoil. This code is based on hydrogeology and hydrostratigraphy. A hydrogeological unit can contain layers from different lithostratigraphic units and layers that belong to the same lithostratigraphic unit can be split up over different hydrogeological units. This code is complete and unambiguous and has a chronological, hierarchical build up. The main units are:

- 0000: undefined;

- 0100: Quaternary Aquifer Systems;

- 0200: Campine Aquifer System;

- 0300: Boom Aquitard;

- 0400: Oligoceen Aquifer System;

- 0500: Bartonian Aquitard System;

- 0600: Ledo-Paniselian-Brusselian Aquifer System;

- 0700: Paniselian Aquitard System;

- 0800: Ypresian Aquifer;

- 0900: Ypresian Aquitard System;

- 1000: Paleoceen Aquifer System;

- 1100: Cretaceous Aquifer system;

- 1200: Jura-Trias-Perm;

- 1300: Palaeozoic Basement.

Delineation of groundwater bodies: The delineation of GWB in Flanders is based on subdivision into five groundwater systems based on regional groundwater flow:

- the Palaeozoic Basement System;

- the Central Flemish System;

- Coastal Plain and Polders System;

- Bruland Chalk System;

- Central Campine System;

- Meuse System.

These systems may be vertically superimposed.

The subdivision in GWB is based on following criteria:

- groundwater system boundaries;

- geological boundaries / semi-permeable layers (HCOV code);

- groundwater divides;

- basin divides (Scheldt and Meuse basin);

- salinisation boundaries;

- district boundaries;

- rivers;

- boundary confined / unconfined part of aquifer;

- isolation of problem areas (e.g. depression cone in Palaeozoic Basement Aquifer).

In Flanders an aquifer will be divided into different groundwater bodies, which is an important difference with respect to other countries where a GWB is mostly built up by different aquifers.

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It should be noticed that the Class III by Finland and the so-called Unproductive Strata by England & Wales are referring to the limit of identification of groundwater bodies defined by the EU – WFD.

However, this specific point doesn’t mean that the other parameters are not taken into account. Moreover, the class “Secondary aquifers” refers at least to hydrogeological characteristics (hydraulic properties).

The others countries are referring more ore less to physical characters of the aquifers in appropriate manner to the national and regional situation:

Countries Classification of aquifers

Austria The following distinctions were made: single GWB - groups of GWBs; shallow GWBs - deep GWBs; predominantly porous media - karst - fractured GWBs (and subtypes).

Belgium

(Flanders) Hydrogeological code for the underground of Flanders (HCOV)

Belgium (Wallonia)

Although no special parameter was explicitly taken into account, it is clear that the division of the region in its different aquifers takes hydrogeological characteristics as criteria. Basic distinction was made between several typologies: fissured and karstified carbonate rocks (hercynian limestones), fissured and porous carbonate rocks (Mesozoic chalks), porous Cainozoic rocks (sands, alluvial deposits).

Bulgaria

The big variety of tectonic geological as well as topographic structures, leads to the big variety of aquifers and hydrogeological conditions prevailing in Bulgaria. With respect to collectors we can distinguish the following types – porous, karst, fissured, porous-karst, karst-fissured, porous-karst-fissured. With respect to the groundwater flow type – unconfined, semi-confined (i.e. the aquifers in the river terraces with two layered structure – lower layer – sands and gravels and pebbles and upper layer – fine sands and clayey sands and clays), confined. With respect to temperature the groundwater are cold and thermal ones.

Otherwise, 7 types of aquifers are defined by their vulnerability:

- First category - Highly karstified limestone rocks;

- Second category - Limestone rocks without open karst forms on the surface and alluvial-drift and drift sediments;

- Third category - Alluvial deposits – river terraces , Neogene sandy deposits in North-West Bulgaria – upper part of Neogene – the zone of recharge, Lower Cretaceous deposits – covered by loess;

- Fourth category – Neogene deposits in sandy-clayey facieses or thinly layered lake sediments – limestones;

- Fifth, sixth and seventh category – Fissured aquifers.

Denmark

An aquifer typology was also given in the Danish guidance document mentioned above. The typology is based on the most important properties of a groundwater body controlling its natural groundwater chemistry, its ability to cause different biogeochemical processes to entering pollutants, and its interactions with and thereby possible influence on surface waters and dependent terrestrial ecosystems.

The following three parameters were used:

- Lithology of the groundwater body, separating between siliceous and calcareous sediments or rocks;

- Contact with surface water, separating between three contact types: part of the year (local), all year (regional) and none (deep);

- Redox conditions, separating between oxidised and reduced;

- This typology gives rise to 12 aquifer / groundwater body types.

Estonia Porous and fracture aquifers.

Finland There is a classification based on the geological type of the aquifer (esker, ice- marginal formation etc.) and groundwater flow pattern (anti- or synclinal).

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France

The first and main level (obligatory factors) includes:

- The GWB are classified, primarily according to their lithology, in the 6 following divisions: Alluvial systems, volcanic systems, crystalline basement, dominant sedimentary rocks non-alluvial, hydraulic complex systems adapted to intensely folded mountain areas, impermeable rocks with local small aquifers, and second according to the different pressures.

- The GWB are classified according to the aquifers flow types with 3 divisions:

confined, unconfined and associated unconfined and confined aquifers.

The second level of characteristics is of minor importance (optional factors, natural vulnerability). It includes:

- karstification;

- the presence of a border coastal area with a risk of saline intrusion;

- the possibility of aggregation into only one GWB of horizontally and/or vertically disjointed hydrogeological entities (aquifers) . These hydrogeological entities may present the same hydrogeological and pressures characteristics.

Germany

To each lithological unit have been attributed criteria as: Rock type, consolidation, conductivity, type of porosity, geochemical type of rocks. Combinations of these criteria are the base for building map titled “aquifer type” (combination between geochemical type and type of porosity) or “upper aquifer” (combination between conductivity, consolidation, geochemical type).

Hungary

Keeping geological-hydrogeological aspects in view, water bodies were designated according to the following hierarchy:

- Waters in predominantly porous formations in basins:

. Cold waters: Subsurface catchment areas:

- Water bodies with dominant downward flow, - Water bodies with dominant upward flow;

. Thermal waters: Water bodies by major hydrodynamic units - Karstic waters: Structural units:

. Cold waters: Water bodies by catchment areas of main groups of springs

. Thermal waters: Water bodies by major hydrodynamic units

- Water in the mixed formations of mountain areas (excluding karstic waters classified in the above group):Water bodies by structural units & surface catchment areas

Lithuania No precision about a specific typology, only inventory.

Netherlands Five types of surface geology are considered: sand, clay/peat, loess, dunes and limestones.

Poland

Poland is divided into two provinces: lowland province and mountain-upland province. In the lowland province mainly the Quaternary/Tertiary porous aquifers are dominating. In the mountain-upland province, the Mesozoic and Paleozoic systems occur. Here, the following classes are distinguished: porous-fissured, karstic-fissured, fissured, porous-karstic-fissured.

Portugal No precision about a specific typology, only inventory.

Spain No precision about a specific typology, only inventory.

United Kingdom (Scotland)

Typology based on following parameters: Overlying strata, transmissivity, confinement, porosity, groundwater chemistry, depth of groundwater flow, length of groundwater flow paths.

As a point to be discussed, we consider that the approaches which are using first a lithological classification and adapt it to local water use through division in sub-bodies may be the most sustainable system in the long term, avoiding major changes of delineation related to changes in water management.

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3.5. Interaction with surface waters 3.5.1. General remarks

One of the key points of the EU WFD is to consider at the scale of entire hydrographic catchment areas (River Basin District) the two water cycles components: surface water and groundwater bodies.

These water bodies are characterised through:

- Quantitative and qualitative status in the case of groundwater bodies;

- Qualitative and ecologic status in the case of surface water bodies.

Curiously, the WFD does not take into account the quantitative status of the surface water bodies. The link between both types of water bodies is assumed through the constraint that the exploitation of groundwater bodies mustn’t threaten the good ecological status of ecosystems (wetlands and rivers). The good environmental status concerns the qualitative but also quantitative issues. One should not forget that in low water regime (no rainfall), the rivers are exclusively recharged through the input of aquifers. Therefore, the exploitation of the aquifers will reduce this recharge component. In case of overexploitation, there is no more discharge of aquifers to rivers. This has been regularly observed in France in the department of Deux-Sèvres and Charente-Maritime. In these cases there is no adequacy between the available water resources and the production yield.

In general these quantitative and qualitative interactions are often insufficiently known (few measurement or studies). Despite of the evidence of the relations, the impacts are underestimated (lack of available data). Thus in France, only 21 groundwater bodies presenting quantitative risks are listed without clearly identifying those which will present definitively a risk for the surface bodies in 2015.

3.5.2. Specific comments on responses

Most commonly, ongoing studies on the interaction of surface and groundwaters focus on protected areas (Natura 2000, Habitat and Bird Directive sites, RAMSAR wetlands, national parks, etc.).

Beside the quality problems, England & Wales define specific classes for rivers and lakes referring to the influence of groundwater abstraction. On the other hand Denmark introduces a detailed typology of the interaction according to the dominant water input: Precipitation dominant wetlands – Groundwater dominant wetlands – Surface water dominant wetlands.

Poland and Estonia mention problems of interactions with surface water linked with mining activities.

Hungary mentions the decrease of temperature of a thermal source (source Heviz) as a consequence of large water abstraction (mining activities). Otherwise, 33 biotope types (both aquatic and terrestrial ecosystem) are identified where groundwater plays a significant role on preserving their good status. 85 water bodies are concerned by these interactions.

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3.6. Assessment of pressures

Pressures are presented in more or less details. However a majority of countries which have provided an answer have mentioned nitrates, phosphates and pesticides as important pollution issues. Agricultural activities, but also urbanisation (leaking sewers, etc.), are pointed out as pollution sources.

Typical urban and industrial pollution are also mentioned but to a lesser extent.

Saline contaminations are mentioned in nearly all countries with coastal areas.

At least, Bulgaria, Denmark, France, Hungary, Spain, England & Wales and Scotland are pointing out that these pressures, especially for diffuse pollution sources, have been evaluated using maps, data-banks and GIS-software.

Hungary describes the following method of pressure evaluation for point source of pollution:

The load of pollutants cannot be directly estimated. It is replaced by the estimation generalized hazard index, i.e. the recharge at the polluted site is multiplied by the ratio of the concentration at the receptor level (top of the aquifer used or intended to use for drinking water supply) and the threshold (standard) of the given pollutant. This simple method corresponds to recharge areas (dominantly downward flow until the top of the aquifer and downward and horizontal flow further in the aquifer). The database of the point sources provides the location, the extension of the site, type of the pollutant, information on the already polluted zone (not for all sites), and rarely the observed concentration in the groundwater. Recharge maps are available for the country. Because of the often missing starting concentration, the ratio of the real concentration and the threshold is included directly as a factor of hazard, since usually this ratio is increasing with hazard of the pollutant (e.g.

for macropollutant is in the order of magnitude of 10, while for hazardous micropollutants it can reach 1000s and for others in between).

3.7. Assessment of vulnerability

Utilisation of the DRASTIC software: Bulgaria, Portugal, Spain.

No mention of vulnerability map for Hungaria.

Otherwise, besides the general mention of vulnerability maps, several countries indicate which parameters and assessment methodology have been used:

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Countries Vulnerability / maps and methodology

Bulgaria In 1981 in Bulgaria was made a hard copy map on vulnerability of groundwater. The principles for creating it are as follows:

- geological and hydrogeological conditions in aquifers situated nearest to the surface - permeability, unsaturated zone – permeability, tectonic zones, recharge conditions;

- as a basis the migration characteristics of nitrates and chlorides were used, which are not involved in adsorption processes and decay;

- the basis is the hydrogeological map of Bulgaria S 1:200,000 of 1975 and the Geological map of 1962 S 1:200,000 and the Map of Quaternary deposits and geomorphology of North Bulgaria of 1975.

7 types of aquifers concerning the vulnerability are distinguished:

- First category - Highly karstified limestone rocks;

- Second category - Limestone rocks without open karst forms on the surface and alluvial-drift and drift sediments;

- Third category - Alluvial deposits – river terraces , Neogene sandy deposits in North-West Bulgaria – upper part of Neogene – the zone of recharge, Lower Cretaceous deposits – covered by loess;

- Fourth category – Neogene deposits in sandy-clayey facieses or thinly layered lake sediments – limestones;

- Fifth, Sixth and seventh category – Fissured aquifers.

Denmark There has been a national analysis of vulnerability of groundwater bodies in relation to pollution with nitrates, in which the national counties have designated nitrate- vulnerable areas based on hydrogeological parameters.

France One must clearly specify the concept of vulnerability distinguishing:

- general intrinsic vulnerability of the aquifer;

- specific conditions of vulnerability depending on the various types of pollutants.

Attention with the application of these criteria of vulnerability to the GWB for:

- various types of pollutants;

- areas varying from a few tens of km² to several tens of thousands of km².

Maps of vulnerability have been established since the end of the 60’s using different approaches at different scales.

The current French guide (may 2003) doesn’t give explicitly a specific method to be followed. Only elements of appreciation of the aquifer vulnerability are listed.

Parameters like surface slope, precipitation, impermeable covering layers, thickness of the non saturated zone, permeability of the aquifers have been evaluated. The combination of the parameters, each having a different weight factor, allows calculating a vulnerability index.

The aquifer vulnerability has been included in the assessment of the risk of failing good status (comparison between chemical analysis and pressures). In that case, it concerns pesticides, nitrates, ammonium, Cl, SO4, chlorinated solvents and others pollutants if available.

In 2004, the BRGM has developed a methodology based on two GIS: The existing hydrographic networks (data base CARTHAGE) and the theoretical talweg (after the Digital Model of Ground). The comparison of these two categories of information allows evaluating a broad surface run-off factor and, conversely an average infiltration factor. This result combined in particular with the parameter “depth of the non- saturated zone” gives a first approach of the intrinsic vulnerability. This method has been applied by 4 river basin agencies in the frame of on-going studies.

Germany The geological surveys and BGR (working group on WFD) have established a vulnerability map for the purposes of the WFD. More detailed vulnerability maps exist in some federal states or for special regions. The methods used are based on the evaluation of the characteristics of the covering layers.

Lithuania Main parameters included in vulnerability mapping are: depth of shallow groundwater, lithology and velocity of water movement throughout the vadose zone. In future this methodology is planned to be validated using data of surface water bodies at risk.

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Poland The vulnerability map of Poland (1:500,000) should be accomplished in June 2005.

(The main parameter is the travel time – Mean Residence Time MRT, of a conservative solute based on the piston flow model. MRT means exchange of total water column in the covering profile by recharge rate).

Information layers of GW endangering factors (five classes) are existing in an electronic version of Detailed Hydrogeological Maps (1:50,000) covering the whole country.

Spain No vulnerability maps have been elaborated for the entire Spanish territory. But such maps exist for some specific areas. For limestone aquifers, the “COP method” is used.

It is the result of multiplying three factors: O (Overlaying layers), C (flow Concentration) and P (Precipitation). Factor O refers to the capacity of the unsaturated zone to protect and filter the pollution. Factor C refers to the surface conditions that have an influence on the water flow to the maximum infiltration zones, where the possibilities for human actions are less. Factor P refers to the influence of rainfall for the transport of pollutants to the saturated zone. Factors C and P are corrective factors for the protection degree of aquifers defined in factor O.

Vulnerability is assessed by considering the following parameters:

- Soils – Vulnerability maps have been produced for the whole of England and Wales.

The soil vulnerability is based on the parent rock type. The categories of vulnerability are divided in to High, Intermediate and Low for each aquifer type (Major / Minor / Non aquifers). The present maps do not take surface drift into account.

- Aquifers – The Environment Agency currently subdivides permeable strata using a classification system which is predominantly based on the ability of the strata to attenuate contaminated recharge water entering at the surface (Policy and Practice for the Protection of Groundwater, 1998). Major aquifers are the most permeable and are usually capable of supporting large abstractions. Minor aquifers are less productive but still form an important resource. Finally, formations with negligible permeability are classified as Non Aquifers.

- Source Protection Zones – Source Protection Zones are delineated around groundwater abstractions used for public water supply, food use or potable supply.

Source Protection Zone I is the highest risk zone, and represents a 50-day travel time for water in the saturated zone of the aquifer to the abstraction point. Source Protection Zone II represents a 400-day travel time in the saturated zone of the aquifer to the abstraction point and Source Protection Zone III represents the total catchment area for the groundwater abstraction.

- Unsaturated Zone – The depth from the base of the proposed activity to the water table, the available depth of unsaturated zone is calculated. The unsaturated zone is considered as an important potential barrier to potential pollutants. The attenuation parameters and the depth of the unsaturated zone are taken into account.

- Post – WFD – The aquifer typology terms are changing from Major / Minor / Non – aquifers to Principal / Secondary / Significant Drift and Non-productive aquifer units.

It is possible that other changes will be brought in too. The Policy and Practice for the Protection of Groundwater is due to be superseded by the Groundwater Strategy.

United Kingdom (Scotland)

Vulnerability map to describe geological pathway. Key elements are thickness &

permeability of strata overlying the groundwater body. Properties of aquifer are largely mapped separately. Together they describe the vertical and horizontal pathways by which pressures can reach receptors.

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Belgium

(Flanders) Groundwater vulnerability maps have been made in 1986 for each province (5 in total) in Flanders on a scale of 1:100,000. The vulnerability map can be described as a map of the degree of risk for pollution of groundwater in the upper water-bearing layer by substances that enter the soil from the ground surface. The degree of vulnerability is based on the nature of the rock and the permeability, the presence, nature and thickness of a covering layer and the thickness of the unsaturated zone.

Vulnerability with respect to nitrate pollution: For the purpose of evaluating the specific vulnerability with respect to nitrate pollution, Flanders has been subdivided into hydrogeological units and zones, based on geological characteristics (e.g. thickness of Quaternary deposits, different ages of Palaeozoic clay layers). The nitrate sensitivity of each zone was assessed on the basis of the following hydrogeological characteristics:

hydraulic conductivity, hydraulic gradient, degree of oxidation of the sediment during deposition, thickness of the unsaturated zone, thickness of the saturated oxic zone, absence in the sediments of effective reduction capacity (reactive organic matter or sulphides).

The table shows that most of the participants are using several parameters which allow assessing the aquifer vulnerability. Usually, this vulnerability can be represented in a synthetic map.

3.8. Risk assessment 3.8.1. General remarks

The EU countries should identify the groundwater bodies which risk failing a good environmental status in 2015. In this task, they are supported by the WFD and the other EU- documents which have been especially elaborated (guidelines and methodologies). Some countries like France have elaborated their own national methodological guidelines for the risk assessment. Taking into account that the EU daughter directive is still under elaboration, the French Ministry of Environment has formulated hypotheses of work. The other EU- countries have certainly proceeded in the same way.

The status of a groundwater bodies is the result of a cross-analysis of all risks (see page 35 to 37 of the guide):

- Quantitative risks;

- Qualitative risks.

For each groundwater body the worst status case will define the general status.

The methodologies are varying between the countries and certainly here an effort should be put into harmonisation.

3.8.2. Methodology

Countries Methodology for Risk Assessment

Bulgaria On local level Methods are available that are approved by the Minister of Environment and waters (MoEW), as well as Methodological Instructions (1998) about the scope and content of the report on determination the damages of contamination previous to privatisation. The procedure of this evaluation concerns the liability of the government for proved previous pollution damages, i.e. the new owners “shall not be liable for ecological damage caused by past actions or lack of actions”. The process of making this report involves a two-stage procedure:

- The first step is preparing a preliminary report, filling up questionnaires and forms

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for identifying the contamination concerning the groundwater, the surface water, the soils and the air - by assessment on the basis of a point system (the score is calculated). Useful are the help work-schemes with list criteria for probability of the groundwater contamination, soil contamination etc., and criteria for selection of primary objectives of impact concerning groundwater, surface water, soils, air.

- The calculated score determines whether the second step will be applied (only for groundwater and soils). After the careful study of the available information about the groundwater and soils there is composing “Plan about additional investigations of the enterprise’s site” on the basis of the “Methods of ecological risk assessment”, the “Dutch target and intervention values for soil and groundwater” [Dutch target..., 1993], and the experience of other countries (Czech Republic) on these problems. The aim of the additional investigations is to evaluate soils and groundwater conditions and impact factors (polluters), in order to determine the extent of soil and groundwater contamination. The additional researches supplement necessary information about these evaluations.

There is approved a local monitoring network and the remedial measures.

The a.m. Methods and Methodological Instructions have been applied for many industrial sites and reports are available in MoEW.

Another methodology was developed under Twining project with Germany (the State Ministry of Environment and Agriculture – Saxony) giving rise to the ”

Instructions for assessment and treating of previous damages” (2001) - It is based on Saxon methodology;

- It includes quantitative assessment for groundwater;

- The risk assessment was performed on 4 levels;

- It uses the Computer Programme GEFA.

The assessed factors (criteria) are:

- Characterisation of the potential dangerous substances;

- Characterisation of the emission of dangerous substances from the pollution sources;

- Characterisation of the discharge to groundwater;

- Characterisation of the migration processes and behaviour of dangerous substances in groundwater;

- Characterisation of the present groundwater use and potential use of groundwater.

The a.m. instructions are applied in practice (2001-2002) for risk assessment of the bigger municipal waste landfills in Bulgaria – 59 in number. The number population (citizens) are disposing upon these waste landfills was then 6,596,170.

France The chosen methodology is pragmatic in order to be adapted on the different cases.

In fact, the amounts of available data are strongly unequal between the groundwater bodies.

This methodology is based on the analysis of:

- data provided by existing monitoring networks (quality and quantity): comparison with thresholds and limiting trend evolutions;

- current and estimate pressures information;

- vulnerability of the GWB.

Otherwise, the spatial distribution of the points of measurement and their representativeness referring to the intrinsic vulnerability are taken into account. In case of lack of representativeness, it will be evaluated by expert judgement.

In spite of the delay taken for the groundwater directive’s publication, a few hypotheses have been set up to assess the risk of failing good chemical status:

- Point sources of pollution, particularly the industrial caused pollution, are in general considered to be under control. The assessment is thus mainly based on diffuse pollution (nitrate and pesticide) and to a minor degree on other pollutants (essentially chlorinated solvents, chlorides, sulphate and ammonium);

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- While waiting for the specifications of the daughter directive, a “good status” water is a water for which at every point concentrations are below the norms mentioned in the Drinking Water Directive;

- a risk is established in cases where concentrations:

. exceed 80% of the parametric values mentioned in the Drinking Water Directive (except for pesticides for which the 0.1µg/l limit has been kept, as well as for other pollutants like ammonium or chlorinated solvents), . show significant and durable rise of the concentration of a given

pollutant (5mg/l in 5 years for nitrates, 10mg/l in 5 years for sulphates, etc.).

Germany Referring to the received document Workshop LAWA-EUF Bonn, the following remarks can be made:

Each German state has its own approach, however the methodologies used are in general comparable. Qualitative and quantitative risk assessments are divided respectively in diffuse and point pollution sources in groundwater balance and ecosystem issues.

Concerning the diffuse pollution sources, the majority of the German states are using the 25mg/l nitrate concentration value over 33% of the surface of the groundwater bodies to define the risk criteria. However, other parameters and surface value are mentioned but with more variations between the states.

Refuse Dumps associated with an impact over 33% of the surface of the concerned groundwater bodies are the generally mentioned cases of risk coming from point pollution sources. There are also here some variations of criteria between the states.

Quantitative risks associated with water abstraction are in majority defined by the limit of variable % of withdrawal (10, 20 or 50%, depending on the state) compared to the recharge of the groundwater bodies.

There is no common methodology concerning the risk of impact on ecological systems. Some states are not including ecological systems in the risk assessment.

Others are in an ongoing evaluation.

In general, the results show that for a majority of Groundwater bodies risks associated with diffuse pollutions.

Hungary The risk assessment is linked with three interactions:

- Wetland ecosystem of river and lake;

- Terrestrial ecosystem;

- Man (and the products consumed by man.

The risk assessment includes the following single assessment issues:

- Groundwater bodies have been analysed with respect to diffuse nitrate- pollution in detail, based on the evaluation of monitoring data (imm ission approach) and on estimated load to groundwater (emission approach).

- Pesticide could be analysed at country level only, because information is not enough for doing it for each groundwater body.

- Impact of point sources has been checked also from both immission and emission point of view. Taking the monitoring data of further 25 elements (NO2, Na, PO4, F, Al, B, Ba, Cd, Cr, Cu, Hg, Mo, Ni, Pb, Sb, Se, Sn, Zn, TPH, naftaline, fenol, BTEX, PAH, chlorinated hydrocarbons, halogene aliphatic hydrocarbons) we found 10 water bodies where in more than 20% of the wells the average concentration exceeded the Hungarian standard.

- The potential pressure from point sources based on a generalized hazard index lead to identify two further water bodies as “possibly at risk”.

- Higher concentration than the standard value in the case of As, NH4, Fe, Mn and organic matter content is considered as results of natural geochemical phenomena

The

Netherlands

The approach for assessment of the chemical status of the GWB was the one used by the WFD but was also based on expert judgement. A GWB has a good chemical status when concentrations of polluting components:

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- do not show any effect of saline of other intrusions;

- do not reach the threshold values as defined in the WFD (thus only yet for nitrates and pesticides);

- are not as such that the environmental objectives for related surface water bodies are not attained, the ecological status or chemical quality of the waterbody significantly decreased, or terrestrial ecosystem (directly dependent from the GWB) were significantly damaged.

Many groundwater dependant ecosystems are damaged because of ‘verdroging’

(drying out), a Dutch term that encompasses changes in the abiotic conditions of the ecosystem, i.e., changes in groundwater level as well as chemical composition of pore water.

Poland Expert judgement was used for assessment of risk at failing good chemical status (based mainly on existing inventory of pollutant sources, monitoring data and expert judgement.

Spain Criteria used to identify groundwater bodies according to the risk of failing good status are the following:

- Bodies with proven pressure (with respect both to quality and quantity) where the impact has been verified. Risk is sure and the water body must be declared in

“Bad status”, and a further characterization must be done;

- Bodies with proven pressure, in which the impact has not been detected, though likely it will occur in the future. Risk is being studied and the water body must be declared a “Under risk”. In this case, monitoring networks shall be designed and put into operation in order to verify if the impact occurs or not;

- Bodies with a proven impact, but the pressure that originates it is unknown. Risk shall be studied and the water body must be declared as “Under risk”. A further characterization must be done;

- Bodies without significant pressure and with no impact. Risk does not exist and the water body must be declared as in “Good status”;

- Bodies without information about pressures or impacts. Risk cannot be assessed and the water body must be declared “Without data”.

The recipients considered have been: dependent ecosystems, water for urban supply, and groundwater.

The applied parameters for the risk assessment are a mixture of land use issues (urban, mining), identified contaminants (nitrate, pesticides, phosphate) and special cases (saline intrusions, point sources). A separate analysis is realised for each parameters.

All the assessments aimed to determine failure of environmental objectives which is in fact wider than simply good status. This is the reason that trends assessment was included and also consideration of protected area objectives, where appropriate. As good chemical and ecological status has yet to be determined for surface water bodies, this was considered as an initial assessment to determine whether there may be pressures acting on the groundwater body that may impact the groundwater body itself. An assessment can then be made to determine if the potential impact on the groundwater body could have a detrimental effect on surface water bodies, protected areas and groundwater dependent terrestrial ecosystems.

The receptors considered in the assessment are the surface water bodies but pressures on (and concentrations in the groundwater body) have been used to identify any risk to surface water bodies. The only assessment that explicitly tried to calculate the concentration at the rivers was for the assessment for phosphate as the river was considered the only target (due to the low EQS), unlike the other assessments where drinking water abstractions could have been considered as a target. This assessment used both the type of river (calcareous, siliceous, organic) and the baseflow index of the catchment.

Belgium

(Flanders) A preliminary evaluation of the quantitative status of groundwater was obtained by studying time series of piezometric measurements of at least 10 years. If the GWB shows no trend (with or without seasonal variations) the GWB has a good

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quantitative status. If a decreasing trend is observed in the measurements, the GWB will have bad quantitative status.

A preliminary evaluation of the groundwater quality was performed for each groundwater body by means of the results of the measurements on the phreatic monitoring network, focusing on the nitrate concentration. The Flemish Environmental Administration (AMINAL) uses the rule that a groundwater body has a good qualitative status if at least 95% of the total number of monitoring points is not exceeding the standard for nitrate.

3.8.3. Preliminary evaluation of aquifers being at risk

There is no information in some cases (Austria, Estonia) and a more or less ongoing classification in other cases (Bulgaria, Denmark, France, Germany, Lithuania, Poland, Portugal, Belgium, Spain and England & Wales). Referring to the WFD, the groundwater bodies must be classified into only two classes: “at risk” and “not at risk”. However, four countries are introducing a third class: France (“at doubt”), Netherlands and Hungary (“possibly at risk”) and Scotland (“probably at risk”). The question remains open about Finland: the so-called Class III (“groundwater areas which need further studies to find out the suitability of the area for water supply”) might be interpreted also as an intermediate case.

Concerning France, the water basins which belong to this third class show following characters:

- Some information are available, but further studies are needed to clarify the status;

- Few or no information are available, a complementary programme of measurement and following interpretation should be established and accomplished.

Not all basin-districts in France are using this third class.

3.9. Open questions

Is the surface of the whole country supposed to be covered by Groundwater bodies? If not, what are the justifications?

A key issue for the evaluation of the assessment of GWB is the water abstraction (drinking water supply, irrigation, industrial uses). However this issue can vary between the countries.

Thus it would be interesting to know for example the percentage of drinking water which is provided by groundwater abstraction.

What kinds of actions are planned for the intermediary classes of Groundwater bodies which are qualified “at doubt”?

3.10. Concluding remarks

This synthesis of replies to questions related to delineation and characterization of GWBs is based on very heterogeneous information and would require further complementary details.

However some general features can be already pointed out.

3.10.1. Definition of the terms

It is necessary to clarify the terms used and their significance so that all contributors or participants will speak the same language. A certain number of terms employed are not defined in the WFD. This is particularly the case for the following terms:

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- River Basin District and Sub-river Basin district;

- Groundwater Body and Sub-groundwater Body;

- etc.

3.10.2. Current state of RBDs and GWBs

It would be useful to have a more precise current state of the number of RBD, sub-RBD, GWB, sub-GWB.

3.10.3. Typology of GWBs

The information provided by the responses to the questionnaire does not allow a synthesis on the typologies used by the various states of EU to delimit GWBs. However, the majority of the states are referring to the limits of the hydrogeologic entities, which are themselves mainly based on the lithological characteristics of the aquifers. To define the GWBs typology, the countries are combining in different proportion purely hydrogeologic characteristics with characteristics of intrinsic vulnerability (standard of flow, presence or not of an argillaceous cover, etc.) and/or the human pressures which influence the aquifers.

Under these conditions, the delineated GWBs do not have the same significance and/or homogeneity in quantitative and qualitative terms.

3.10.4. Numbers and dimensions of RBDs

Information collected is partial. However, it would be useful to have a general map, of RBDs for the whole of EU, even subject to later modification.

In France, the surface of the 13 RBD varies between 1,085km² (Martinique) and 156,915km² (the Loire, coastal Vendee and Brittany).

3.10.5. Percentage of surface of the country covered by the GWB

According to countries', the GWB cover or not the totality of the surface of the territory:

- In the majority of the countries as in France and Austria, the GWB cover the totality of the territory.

- In other countries the GWB cover only one small part of the territory: e.g. in Finland the GWB cover only 4.1% of the territory.

3.10.6. Numbers and dimensions of the GWB The number and the size of GWBs are extremely variable:

- within the same country, - between the countries,

- depending to the type of aquifer.

In Finland, for example, GWBs of class I and II count 3,700 and have sizes from 1 to 2km² (maximum 100km²). GWBs of class III are totalising 3,188.

France, counts 559 GWBs. Their size lies generally between 1 and 61,021km², the general median being of 733km². GWBs of the alluvial type have a median size of 209km² whereas