Hydrogeology in the Scivice of Man, Mémoires of the 18th Congress of the International Association of Hydrogeologists, Cambridge, 1985.

GROUNDWATER CONSERVATION AND PROTECTION IN DEVELOPED COUNTRIES

J. MARGAT Bureau de Recherches Géologiques et Minières, Orléans, France.

ABSTRACT The management and protection of groundwater is just one task of

the hydrogeologist. It is also the hydrogeologist's job to analyse the available potential and the constraints imposed by the physical conditions of the natural environment, to foresee and demonstrate the consequences of multiple human activity on ground­water resources, and to formulate and propose the technical methods most suitable to satisfy the desired objectives. However, as is the case for all water resources, for renewable natural resources in general, and for the environment itself, the aims of groundwater management and protection, together with the ways and means appropriate if such aims are to be met, depend on the viewpoints and objectives of many other operators and decision-makers. Just as hydrogeologists may contribute towards increased understanding of other parties and to decision-making at various levels, so must they themselves understand the nontechnical aspects involved.

The purpose of this overall review of the problems involved in groundwater management and protection, particularly in developed and industralised countries where these problems are most complex, deliberately goes beyond strictly scientific and technical aspects. Inspired by contemporary works of analysis and synopsis, especially those produced by the Committee on Water Problems of the United Nations Economic Commission for Europe (NU-CEE, 1983), this aide-memoire aims to provide hydrogeologists with a general framework within which to set the analyses and proposals they might have to present to authorities responsible for water policy.

This paper thus aims:

1) To review the advantages of groundwater as a resource in relation to human requirements, in addition to the function of groundwater as a component in the natural water cycle.

2) To evaluate the present and future importance of groundwater, particularly in relation to water supply.

3) To draw attention to the quantitative and qualitative sensitivity of groundwater to human activity.

4) To shed light on the possible consequences of excessive exploitation and qualitative deterioration of groundwater, either in terms of human consumption or of the natural environment, both now and in the future.

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INTRODUCTION In most countries of the temperate northern hemisphere, ground­

water represents a significant and in places predominant proportion of the available water resources. Its exploitation also contributes substantially to satisfying water requirements, particularly in relation to potable water for human consumption. Commonly easy and economical to exploit, as well as much sought after because of its advantages, groundwater nonetheless represents a resource sensitive to the risks of excessive exploitation and to qualitative degra­dation as demographic and economic growth advances in many industrialised countries. Moreover, the authorities responsible for the administration of water and for the management of water resources in such countries attach great importance to its conser­vation and protection.

Although it is true that, together with other water resources in the natural environment and in particular continental freshwater, groundwater possesses specific characteristics (see below), it should not be forgotten that it represents a component of the natural water cycle, interacting in various ways with surface waters both upstream and downstream of its own course. Groundwater resources are therefore not generally independent of surface water resources, but offer various degrees of relative autonomy and allow conjunctive development or coordinated utilisation. This has consequences for the management of groundwater resources, both from a quantitative and qualitative viewpoint.

No groundwater conservation and protection strategy which is reconciled with development resulting from groundwater use can therefore be either conceived or applied independently of a general strategy for water development and use, or independently of a strategy for surface and subsurface land use, including exploitation of other subsurface resources.

The specific nature of groundwater as a water resource is initially the result of the physical conditions under which it occurs, of its distribution, and of its regime within the natural environment. Hydrogeologists are of course familiar with these characteristics, and there follows a short list of factors of which persons responsible for the administration and management of water resources must be made aware:

1) The very wide range of structural dimensions (extent, thickness, depth) and of characteristics which determine the hydraulic properties (permeability, storativity) of groundwater "deposits" or aquifers.

2) The relatively continuous spatial extent (sheet-like bodies of groundwater), at least in porous or microfissured aquifers, and the non or poorly hierarchical structure of groundwater flow systems (in contrast to surface hydrographie networks).

3) Aquifers combine the functions of distribution and storage, which are however more or less separated in detail by geologic heterogeneities. There is hence a variable but generally substantial degree of autoregulation in groundwater bodies: an aquifer transforms discontinuous and irregular inflow into continuous and more regular outflow.

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4) The great variety of regimes, flow velocities, and degrees of hydrodynamic inertia (the type of reaction to natural or artificial stresses). There is a major difference, governed by the geologic structure, between unconfined groundwater, which has high rates of flow and for which replenishment is mainly dependent on hydrometeorologic conditions, which are variable, and deep-seated confined groundwater stocks which are renewed more slowly and with low rates of flow, but which respond rapidly to pressure changes in contrast to the unconfined state.

5) Various physico-chemical interactions between water and soil or rock, favoured by the large surfaces of exchange and by the long time spent by the water in the aquifers.

These physical characteristics condition the role of groundwater to chemical change. They also condition approaches to the knowledge, mobilisation and conservation of such water. However, the great variety of conditions renders it inadvisable to make general and uniform assessments of groundwater resources.

GROUNDWATER RESOURCES: ADVANTAGES AND CONSTRAINTS The natural conditions reviewed above mean that many groundwater

resources display advantages recognised and applied profitably for many years, making them a preferential source of water supply exploited to satisfy the requirements of multiple users. These advantages are related to quantity and to practical conditions of exploitation as much as to water quality. However, they are not universal, and particular constraints are applied to the mobilisation and management of groundwater resources.

Groundwater is commonly accessible and exploitable by fairly productive catchworks of limited extent. Very varied exploitation equipment may be designed and used and the space taken up at the surface is minimal. The constraints of location, although not negligible (eg. heteregeneous distribution of productivity and discontinuity of some aquifers), are considerably less than for surface water. The energy cost of exploitation is often nil (gravity catchworks, artesian wells) or minima] (pumping from shallow depth).

Groundwater is a permanent and extensive resource which does not necessitate the installation of equipment such as is needed to regulate and use surface water. It can generally be drawn off directly and is available to the many individual or collective commercial entities which occupy the land and which may exploit the resource either for their own use (household, agricultural or industrial enterprises) or for distribution as a consumable, generally as drinking water (including bottled water). The investment required for exploitation is easy to subdivide and to spread over time, and the equipment installed rapidly reaches full capacity; all added economic advantages.

Another advantage of groundwater is that it commonly possesses natural qualities which conform to the standards specified for many applications, particularly as drinking water, and are fairly constant in time. The conditions under which groundwater occurs generally ensure natural protection against bacterial contamination (self-purifying by filtration), except for certain types of chemical

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pollution which will be discussed below. For this reason, the production of drinking water from groundwater generally requires appreciably simpler and less costly treatment, and less frequent controls, than the production of drinking water from surface water.

Groundwater accumulates and conducts heat, whether from natural geothermal flow or by introducing a fluid, and thus represents an energy resource which is of particular interest given the current energy crisis. Under certain favourable technical and economic conditions (such as the existence of an appropriate demand for heat systems), the use of deep-seated hot water may be economically competitive for heating of collective housing units, and there is generally no alternative use for such water. Moreover, some countries are developing normal-temperature groundwater (shallow groundwater) in conjunction with heat pumps. In France, for example, about 25,000 water heat pumps exploiting groundwater (Margat et al 1984) were in use in 1982 (all capacities taken together).

On a daily or seasonal scale, "heat storage" in aquifers is beginning to be envisaged and used to regulate or recover waste heat. These new uses of groundwater may compete with standard consumption and conflict with resource management.

Groundwater represents an obstacle to the development and exploitation of subsurface mineral resources. It may be desirable to control or drain such groundwater: the dewatering carried out by extractive industries may itself interfere and compete with exploitation of groundwater as a water resource and disinterested intervention may be required. To a certain extent, the water extracted by mining operations represents a by-product used in particular for drinking water supplies (in France, for example) (CEC 1982), but such use can only be temporary.

Groundwater therefore has multiple but sometimes incompatible applications which bring users and exploiters into competition. The present volume of groundwater abstracted and used (national statistics are given in Table 1) clearly indicates, from a quantitative viewpoint, the extent of the benefits derived from its use.

While having the advantages reviewed above, the natural conditions peculiar to groundwater resources impose specific constraints on their management. Any localised action affecting groundwater has, to various degrees and more or less rapidly, an influence on the entire aquifer concerned, and the effects of successive operations are cumulative. The effects of isolated exploitation within a single aquifer system are combined by the physical conditions, there being no priority from upstream to downstream (in relation to the flow of groundwater) and no immunity against the effects of present or future operations is guaranteed by the fact that any given exploitation pre-dated another.

The reserves in many aquifers mean that temporary or seasonal volumes of water greater than the natural average influx may be withdrawn, which generally frees groundwater exploitation from climatic fluctuation and makes it possible to satisfy peak demands. However, groundwater has no defence against prolonged longer-term disequilibrium of this kind which may result from ill-advised over-exploitation. Moreover, natural groundwater protection is neither absolute nor evenly distributed and does not protect the water quality from various types of direct or indirect attack.

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The quantitative and qualitative conservation and protection of groundwater resources are less spontaneous than development for exploitation and utilisation, being neither conceived nor decided at the local level of the individual operator but at the regional scale of entire aquifers. The appropriateness of the qualifications of the management authorities to deal with aquifers can cause problems because of the fact that aquifer systems, which form natural ground­water management units, are not exactly identical to hydrographie basins, which form surface water management units, and do not coincide with such basins. These authorities can only intervene in indirect ways, using indirect methods to control the activities of operators or economic agents which influence the regime or quality of the groundwater (see below).

The appropriate technical means for obtaining the information necessary for management decisions also depend on the conditions specific to groundwater resources. Although observation of quantitative variables (water levels, spring discharges, etc) is relatively easy, surveillance of quality is more difficult. The long time taken for groundwater to move and mix restricts the spatial representativity of samples, whereas the extension and, in places, the thickness of aquifers necessitate complex sampling networks. Finally, the parameters to be controlled are many and constantly increasing.

To regard groundwater only as a resource at man's disposal is to ignore its role in the natural environment, as a component in the water cycle. Although groundwater in the lithosphère rarely forms a biotope (for example in some karstic domains), in many zones with a shallow free water table it contributes to the regulation of soil humidity exploited by natural or cultivated vegetation. However, the natural association of groundwater with surface waters is particularly important. Aquifers are the main regulators of surface flow: with the exception of snow-filled basins and per­manent water courses and the levels in some surface water bodies.

For example it has been estimated, UNESCO (1978), for the continent of Europe as a whole (including the European part of the USSR), that groundwater represents 99% of the total freshwater reserves, evaluated at 1.4 x 1014 m3, and that the stable flow of water courses essentially originating from groundwater is 1,085 x 10 m3/year, or one-third of total flow. In the USA (including Alaska), fresh groundwater reserves are estimated at 1.2 to 2.2 x 101"* m3 and the base flow originating from groundwater at about 30% of average total flow, evaluated at 2,970 x 109 m3/year, (US Water Resources Council, 1978).

For this reason, groundwater is a permanent and primary factor in many freshwater aquatic ecosystems, in which it influences the volume, flow and physico-chemical characteristics.

If preservation of the human ecosystem, which cannot be dis­associated from the biosphere and hydrosphere, is included in the defined "écologie requirements", it is possible both to see the particular advantages of groundwater as a resource and to appreciate its interaction with the other components of the overall water resources in the natural environment:

1) Groundwater forms by far the greater part of the regular phase of total natural water resources, including surface water. In many countries, it represents the predominant component

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of total stable water flow, either natural or artificial, regulated by storage reservoirs. Generally located at the landward extreme of continental freshwater systems and less concerned with drainage than surface water courses, ground­water systems are the most involved in the preservation of natural water quality.

2) Exploitation of groundwater or modification of its quality by wastes may affect users of surface water or land owners before having adverse effects on the abstractors themselves (eg. excessive production cost, induced deterioration in quality, temporary or prolonged exhaustion of the resource).

The conservation and protection of groundwater must thus aim not only to safeguard its advantages and so maintain its quantitative and qualitative reproducibility as a resource for present and future users, but also to preserve subordinate surface water resources (tapped or used -in situ) exploited by other concerns in partial competition and maintain the indirect natural role of groundwater in relation to ecosystems and geodynamic equilibria. These various aspects of conservation are not always compatible and necessitate arbitration expressed in terms of constraints to which users or other agents whose activities affect groundwater resources should be subjected (that is internal constraints related to the interests of the developers themselves and external constraints in relation to other objectives).

PRESENT AND FUTURE IMPORTANCE OF GROUNDWATER IN WATER ECONOMY A preliminary assessment of the importance of groundwater in the

water economy is given by estimates of the volume of groundwater abstracted, shown as absolute values and in terms of its proportion of the total volume of water tapped, and by estimates of the pro­portion of groundwater used by various sectors of the economy in relation to their respective water supply.

Table 1 combines a certain amount of numerical data for various industrialised countries, such data originating from governmental or regional (inter-governmental) sources. Despite some defects of homogeneity, these data at national scale clearly show the prevailing absolute and relative importance of groundwater as a source of water supply in most developed countries.

In the majority of these countries, groundwater abstraction exceeds one-fifth and commonly one-third of total water abstraction for all purposes, including cooling of thermo-electric power plants. Such abstraction is distributed in varied proportions between the three main sectors of use (human consumption, self-supplied industry, agriculture), varying from country to country. Although most commonly used as drinking water for conurbations, the self-supplied industrial sector in some countries (such as Canada, Federal Republic of Germany, German Democratic Republic, Hungary and the USSR) is the primary user of groundwater. In some other countries, particularly those in the Mediterranean region (eg. Greece and Italy) and the USA, the agricultural sector is generally predominant, representing 5% of total groundwater withdrawn in the USA (1980) and 85% in Greece (1980).

In terms of the proportion it occupies in relation to total water supply for each sector, groundwater occupies a place which is significant virtually everywhere and commonly predominates,

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particularly in relation to urban water supply (the production and distribution of drinking water). In most developed countries, groundwater is the main and in places virtually the only source of drinking water. The proportion of groundwater used to satisfy the drinking water requirement is, for example, 97% in Austria and Denmark, over 90% in the Federal Republic of Germany, 78% in Hungary, and between 70% and 75% in Belgium, the German Democratic Republic, Switzerland, the USSR, and Yugoslavia. Although to a lesser extent (25% or more in several countries) ,

groundwater also significantly contributes towards satisfying the water requirements of private industry and of agriculture, mainly irrigation. Accurate and detailed knowledge of groundwater abstraction none­

theless comes up against various types of difficulty: the uncertainties inherent in assessing the extent of its exploitation and in determining the true annual volume abstracted; the variable estimates of the discharge of the source tapped, of volumes tapped in alluvial aquifers close to rivers (and replenished by such rivers), and of water extracted for dewatering the subsurface (as in mines and underground workings). In the same way, the determination of the distribution of groundwater abstraction related to the principal water users (such as distribution of drinking water to conurbations) and the origin of the water when mixed sources are involved remains difficult. Differences dependent on the various operating organi­sations and countries as regards definition, accuracy, accounting practice and structure and reference date reduce the comparability of the statistics. Efforts to standardise such items would appear opportune, both as regards the national water economy in each country and on an international scale.

The trends in water use are unequally established, and records commonly cover periods which are too short to reveal significant trends in the various countries considered. The available data indicate varied trends. For example, there was an increase of + 137% over 25 years (1950-1975) in the USA (USGS, 1977), of + 54% for the same period in the United Kingdom, of + 70% over 7 years (1970-1977) in Denmark, of + 12% over 5 years (1971-1976) in the Netherlands, and relative stability over the past 5 to 10 years in the Federal Republic of Germany, in Belgium, and in several regions of France (CEC, 1982).

Assessments of future trends for groundwater abstraction and use may be partially based on projections from these trends. However, it is hard to base forecasts solely on extrapolation of trends which are established unequally and often over excessively short periods. Such forecasts also assume that the socio-economic conditions which determine water requirements are invariable and that there is no effect of other limiting factors or voluntary intervention. None­theless, an increase in groundwater utilisation is forecast for most developed countries (eg. France, Greece, Poland, Portugal, Czechoslovakia and the USSR), whereas in other countries use is forecast as being stable up to the year 2000, and in some cases as decreasing (eg. Austria, Belgium, USA). As regards the proportion of groundwater used for drinking water

supply, a decrease is forecast in several countries (such as Canada and Greece, with a drop of 40-50% in Belgium, Poland, Portugal and Czechoslovakia) and stable levels are expected in others (such as

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Austria, the USA, France, USSR and Yugoslavia). The exploitation of groundwater itself represents a sector of

primary economic production involving equipment which it would be of interest to assess in terms of economic value, together with the overall production costs, and to compare with the better-known sectors of surface water development. It would also be instructive to compare investment and operating expenses devoted to the exploitation of groundwater, to its preparation for use (prior treatment), and to its conservation and protection. However, these subjects have to date rarely been the subject of economic analysis and assessment, either from the viewpoint of financial cost evaluation, or evaluation of economic usefulness.

Many countries highlight exploitation of groundwater and the resource it represents. Their aim is:

1) Either to assess the degree of exploitation and reduce or give advance warning of excesses prejudicial to the users themselves or to third parties (see below).

2) Or sometimes to stimulate exploitation regarded as very limited and which could profitably be intensified.

This comparison between abstraction and the resource itself implies reference to adequate units of calculation and management governed by the natural aquifer boundaries. It also poses the problem of prior evaluation of the groundwater resource.

The groundwater resource assigned to a given aquifer is both a multi-dimensional and a relative notion:

1) Multi-dimensional because it is expressed in terms of flux and volume, quality, replenishment regime, conditions of access and cost, and sensitivity to exploitation and to the effects of other activities.

2) Relative because its exploitab'ility is dependent on the criteria of its developers and therefore of their economic objectives, and of more general criteria imposed by public management authorities. The degree of interdependence between groundwater and surface water has a considerable effect on the arbitration criteria: either, in general, where the volume of groundwater abstracted is prejudicial to the discharge of rivers by reducing their groundwater flow component or, in particular, where such abstraction directly taps the water in rivers. In the latter case, which commonly occurs when alluvial aquifers near water courses are exploited, it is difficult to differentiate between the autochthonous groundwater resource and the surface water resource diverted. The exploitable groundwater flow is thus effectively partially dependent on exploitation itself.

Overall the means used to define and evaluate groundwater resources depend both on the type of aquifer and the use to which the water will be put. Such evaluation cannot therefore be reduced to calculations of a simple and invariable order of magnitude. However, the dimension of flux in the groundwater resource is useful because of its physical simplicity and because of the possibility of comparing it with both surface water flow and abstraction, at various spatial scales. This is, however, only a partial index of the value of the resource and can mask substantial differences.

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Even if one sticks to the dimension of flow in the groundwater resource, evaluation is subject to various types of approach according to the country and developer, thus preventing homogeneous overall comparison and conclusions. The following are among the many approaches used:

1) The most common is to consider the groundwater resource as the replenishment flow of the aquifer or of all aquifers in the area considered, which comprises the entire subsurface flow of watercourses maintained by springs and by drainage of continental groundwater, together with hidden groundwater flow leaving the area (flowing into the sea or into neighbouring areas).

2) A less common approach is to limit the groundwater resource to the groundwater flow not collected by springs and rivers, thus to groundwater discharge flowing directly into the sea or into areas where the loss is by evaporation.

A more realistic intermediate approach is to define the con­straints necessary for conservation of spring discharge and of minimum flow in rivers, (a relative and révisable factor for use in arbitration), thus only regarding part of the natural flow passing through the aquifers as a potential groundwater resource available for exploitation.

Another more restrictive approach, not exempt from semantic con­fusion, consists of considering the groundwater resource as the sources of groundwater supply actually used, ie. the maximum water production potential of abstraction installations in service or even to actual production at a given stage. This practice obviously prevents comparison between exploitation and resource because it identifies one with the other.

Despite the diversity of natural conditions, of socio-economic structures of exploitation, and of the differing infrastructures for water administration in the various developed countries, it may prove useful to look for a way of evaluating groundwater resources, even if a unified approach is not possible, (and it may be a problem for which a single solution is not practicable). At least achieving a common concept and language would facilitate scientific and technical exchange in this context (and even facilitate negotiations in the case of certain trans-national groundwater resources).

Notwithstanding the variety of bases and methods used for evaluation, the proportion of flow derived from groundwater resources estimated in relation to total water resources represents a means of measuring the economic importance of groundwater, parti­cularly when the analysis relates to its role in meeting the various demands for water. Table 2 combines published numerical data defining the theoretical groundwater resources at national scale for various industrialised countries.

It can be seen that although in many countries groundwater only represents a minor proportion of total water resources (less than 2% in Finland, 8% in the United Kingdom, 10% in Belgium, the Soviet Socialist Republic of Ukraine and Czechoslovakia), it represents 15% in Poland, 16% in Bulgaria and 22% in Rumania. In some countries the proportion is 40% or more (the Federal Republic of Germany, Austria, and the Soviet Socialist Republic of Belorussia),

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reaching 60% in Hungary and France. The diversity in the orders of magnitude, due in part to

differences in surface area, climate and geologic conditions in the countries concerned, means that such evaluations are heterogeneous and analysis must therefore be made with caution. Depending on the situation, the flow derived from groundwater resources may or may not be included in total water resources. Moreover, by incor­porating groundwater flow into total flow largely composed of flood run-off (which is hard to control), it is easy to run the risk of minimising one of the great advantages of groundwater as a water resource: its constancy.

The importance of groundwater as a resource, possibly distributed between the main aquifers, may also be measured by quantitative indicators other than overall discharge. The extent within a country of areas comprising good quality groundwater which is easily accessible as regards depth and productivity, fairly regularly replenished, and relatively unexposed to the risks of pollution, or easily protected from such pollution, would also be a useful indicator.

Description of the spatial distribution of these characteristics, deduced from analysis of the hydrogeologic conditions and expressed in the form of specific thematic maps at various scales, is fairly advanced in most developed countries. These maps may usefully be compared with those representing the distribution of population and of the main activities giving rise to specific water requirements for which groundwater is suitable.

The volume of groundwater available as a reserve storage within the main aquifers is also part of the resource, acting either as a regulating factor which to a greater or lesser extent amortizes the effects of climatic irregularity (eg. resistence to possible drought) or as a store, that is, nonrenewable resource, exploitable for long-term mining operations under certain well defined conditions. This is particularly the case with large and deep confined aquifers, (Margat and Saad, 1982; Margat, 1982).

The future importance of groundwater will depend less on its quantitative position in relation to water resources used to satisfy total water requirements than on its role as a source of priority supply for use with the most demanding quality and safety requirements, mainly drinking water for human populations. This does not exclude other uses including energy-related applications and indirect application in the case of development of the sub­surface. The future risks of disturbance to the regime, or of degradation of surface water quality, together with the voluntary transformation of such water by installations increasing its artificial nature, will probably increase the value of those groundwater and continental freshwater resourcs which best lend themselves to conservation of their natural characteristics, providing care is taken of them.

The governing principle behind future management of groundwater resources should be to conciliate quantitative and qualitative conservation and protection to a selected level with the kind of profit offered by the groundwater potential, but which necessarily entails certain modifications in the regime.

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IMPACT OF HUMAN ACTIVITY ON GROUNDWATER The specific characteristics of groundwater mean that it displays

varied sensitivity to changes in internal or external conditions. The effects of exploitation and the impact of other human activities affect the groundwater regime or quality and consequently the resource potential and the role of groundwater within the natural environment. The direct dynamic effects of exploitation, such as declines in water level and modifications in flow at the boundaries of the aquifer, are inevitable and are usually necessary to produce the re-equilibration that ensures permanent and constant water production. Such effects may however have undesirable secondary consequences and give rise to external effects similar to the impact of other activities.

The main sensitive factors follow. These are variable in nature and in relation to mutual interaction.

1) Certain structural characteristics, both, at the scale of aquifer geometry and at the scale of medium parameters. These include the position and permanence of aquifer boundaries (which may be moved, obliterated or created), the permeability of soils or specific boundaries (eg. the silting up of river banks or beds, thus modifying flow between surface and groundwater) and the conductivity and capacity of the aquifer itself which may be locally reduced or increased by underground works, such as screens or drains, or by changes in pressure.

2) Levels (ie. hydraulic potential) indicative of aquifer dynamics, dependent on flux conditions at the boundaries (inflow, outflow, withdrawal) or external levels in the vicinity of a boundary under conditions of hydraulic potential (bodies of surface water) and which may in places be directly modified (such as by drainage or screens).

3) Spontaneous flow at boundaries governed by internal levels, such as seepages or exchanges with the soil and the atmosphere (infiltration and evaporation) which may be increased, reduced or even interrupted, and variations and reversible exchanges with surface waters.

4) The physical and chemical characteristics of the water, their distribution and regime, sensitive to the flow of substances (or heat) borne by the incoming water flow, particularly by infiltration or injection, or associated with hydrodynamically-induced internal water displacement.

These sensitive factors may exert influence in very different ways, according to the structural and hydrodynamic conditions of the aquifers. The vulnerability of groundwater to the impact of human activity is also very varied:

1) The water in shallow unconfined aquifers (shallow ground­water) is the most exposed to the the effects of changes of surface conditions or to the modifications in water courses with which such changes are associated. The natural qualitative protection of groundwater by cover rocks is very uneven and is dependent on their nature and thickness.

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2) The interface which separates freshwater from saline water is very sensitive to any change in the dynamic equilibrium of the aquifer, particularly in coastal aquifers.

3) Substantial falls in water level may cause subsidence and irreversible degradation of the hydrodynamic properties of some poorly consolidated aquifers, thus affecting the productivity of catchworks.

4) Accidental modifications in quality persist to a very variable extent depending on the flow velocity of the aquifer affected, but can last for a very long time.

Analysis of groundwater vulnerability factors, particularly in relation to alteration in quality (pollution), together with inventory and cartographic representation of such factors, has already been undertaken in several countries (Federal Republic of Germany, Spain, France, and recently in all the countries within the European Economic Community).

Many human activities have a quantitative or qualitative impact on groundwater affecting one or other of its sensitive components. Apart from the direct and necessary, and often actively desired, consequences of the act of exploitation itself, secondary effects also occur. Direct intervention in the field of groundwater resources for reasons other than use as water is prevalent (thermal use, dewatering of the subsurface, fluid disposal). In some cases, the results aimed at may be identical to the "secondary" effects incurred by standard water exploitation and conflicts are possible, for example between water abstraction and the dewatering of mines (examples exist in the Federal Republic of Germany, the German Democratic Republic, Poland, Czechoslovakia and the USSR).

The use of old wells to dispose of effluents (a practice which is excessively widespread, despite regulations forbidding such use) may directly contribute to changes of groundwater quality, as is commonly the case in many conurbations.

Various forms of permanent or temporary subsurface works (under­ground workings, foundations, quarries and mines) may transform the aquifer structure and influence the dynamics of the water table. This is particularly the case with extraction of material from deposits which form aquifers (eg. aggregate quarries in alluvial aquifers). After mineral exploration has ceased, the excavation offers a site for the disposal of waste, often at the expense of the quality of the surrounding groundwater.

Underground storage of environmentally undesirable industrial substances, either in cavities or, in the case of fluids and in particular of gaseous or liquid hydrocarbons, in aquifers, does not everywhere provide absolute quarantees against the risks of accidental pollution, despite prior safety studies and the precautions generally adopted.

Land use and various hydraulic surface installations may modify the boundary conditions of aquifers, either in terms of level or flow, and thus induce influx of foreign matter:

1) Urbanisation which seals the soil at the surface but causes artificial inflow resulting from the loss of distribution or drainage networks.

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2) Agriculture, which decreases or, by irrigation, increases infiltration, but which can increase diffuse influx of various constituents; rises in level due to irrigation can amplify evaporation more than they increase groundwater flow, particularly in arid zones.

3) Adjustments of watercourses and dams, which modify boundaries and raise or lower the hydraulic potential.

4) The disposal of urban or industrial wastes, whether controlled or otherwise, and the accumulation of mine waste exposed to leaching by meteoric water often leads to the introduction of pollutants into groundwater systems.

Some activities may have a very indirect impact. For example, atmospheric pollution which changes the characteristics of rainwater, particularly in rendering it more acid, can contribute to a change in the quality of groundwater in unconfined aquifers. More acid water (particularly at pH < 4.5) may become enriched in metallic ions in the aquifers or, after abstraction, by causing corrosion in pipe-works (Al, Cd, Cu, Pb and Zn). This has been observed in several countries where the groundwater already has an appreciable natural acidity (Canada, Sweden, USA), (CEC, 1983).

The analytical relationship between sensitive groundwater factors and human activity representing potential causes of problems is expressed in Table 3, which gives an indication of such impact and demonstrates the interdependence of cause and effect.

For example, falls in the average groundwater level may result from intensive abstraction, from a change in surface conditions limiting influx, or from a drop in the hydraulic potential at given boundaries. Such falls in level may in turn cause changes in water quality, which also occur as a result of direct influx of matter.

The advances in creating inventories and measuring the effects of human activity on groundwater in developed countries is uneven. Such work is rendered problematic by the difficulties encountered in defining zero reference levels in regions where changes in the natural environment caused by man are secular, by the minor but extensive nature of many effects, by the multiplicity of available indicators, and sometimes by the lack of permanent organisations equipped to make inventories and analyse the data. The effects assessed are mainly concerned with groundwater levels and with groundwater quality parameters (the two often being associated) in certain zones, the secondary effects being regarded as accessory influences.

Substantial falls in groundwater levels due to abstraction, .in places reaching 100 m or more, are evident in areas of intensive urban or agricultural exploitation in various countries (particularly the Federal Republic of Germany, Spain, France, the United Kingdom, USA and USSR). Some well known instances are the result of cumulative effects over a long period (a century or more), for example California (USA), the Lille and Paris regions of France, and the Dnieper-Donetz and Azov-Kouban basins of the USSR. Others, which have become accentuated over a decade or more, are the result of rapid urban or agricultural growth in localised areas, and falls in level in places are occurring at rates of one to two metres per

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year. Such examples exist in Spain (a fall of 200 m in a limestone aquifer near Alicante between 1976 and 1982 (Pulido-Bosch et al, 1982), in Italy (up to 40 m in Milan's alluvial aquifer (Bortolami et al, 1978) and in the USA (20 m between 1949 and 1968 in the High Plains aquifer in Texas (Texas Water Development Board, 1975). In several coastal regions, levels have fallen below sea level. Examples exist in the Federal Republic of Germany, Denmark, Spain, Italy, the Netherlands and the United Kingdom.

Major local or regional falls in groundwater levels also result from dewatering carried out by mining operations, commonly over several decades.

The present-day changes in the areas affected are generally monitored and recorded, but data are less readily available on earlier trends and vary from country to country.

Hydrogeologists may be well aware of the fact, but the exploiters of groundwater do not always understand that such falls in level are not everywhere equally significant. This depends on whether unconfined or (deep) confined aquifers are involved. Of the cases cited above, the alluvial aquifers of California and Arizona in the USA and the chalk aquifers of northern France are unconfined aquifers in which falls in level are due to substantial water extraction. In contrast, the deep aquifers of the Dnieper-Donetz basin in the USSR, and the London and Paris basins are confined aquifers in which falls in level are the result of a drop in water pressure and are not accompanied by dewatering of the reservoir (although dewatering has occurred in central London).

Falls in level also depend on whether conditions of dynamic re-equilibrium have been established or not. It is well known that exploitation of confined aquifers necessarily causes substantial and long-lasting falls in level and draws on the aquifer reserves for a long period before re-equilibrium can be established.

The diagnosis of "overexploitation" or "exhaustion" of a ground­water aquifer thus requires more pertinent analysis than simply recording a fall in levels (Margat, 1977, 1982).

The extent of areas of groundwater overexploitation is nonetheless appreciable in several countries, assessed (in 1976) at 16% of the total area of the Netherlands and 4% of the United Kingdom (CEC, 1982). In the USA, groundwater exploitation exceeding influx is recorded in 60 sub-regions out of 106, and is regarded as critical in 8. A total of 29 x 109 m3, or 25% of the total volume abstracted in the country, originates from such overexploitation (US Wat. Res. Counc, 1978).

Falls in level can cause secondary effects which have been observed in several countries:

1) Invasion of coastal aquifers by seawater (eg. in the Federal Republic of Germany, Malta, the Netherlands, the USA and the United Kingdom.

2) Influx of deeper water with high salinity or temperature which modifies the water quality of the aquifer (eg. USA and Hungary).

Modifications in the chemical characteristics of groundwater are also evident in various countries, but are very varied in nature and extent. Some are localised and specific, resulting from accidental pollution or from the permanent effects of inadequate purification

- 283 -

of urban, industrial or stockfarm effluent which has partially infiltrated. Others are extensive and chronic, evolve slowly, and are the result of agricultural practices (nitrates), domestic effluent where habitations are dispersed, or the secondary effects of industrial waste (acid rain).

Description of the existing state of groundwater quality, defined by various parameters and criteria, is fairly advanced in most countries, although procedures and means of presentation vary. Such description may be expressed:

1) Either by parametric maps describing the distribution of constituents in the water or of other accepted quality indicators.

2) Or by maps normally classified according to one or more uses. Such maps show zones of groundwater pollution together with the type of change observed.

Historical data enabling quantification of trends and definition of reference criteria for natural constituents are less common. Also, the extent and type of degradation in groundwater quality, whether or not associated with identified factors, have to date not been subjected to methodical inventory and representation at a national scale which would make it possible to make pronouncements as to the "purity" of groundwater from region to region. However most of the obvious cases are known, and appropriate local or regional observation networks are being set up in various countries to provide advance warning and analysis of trends. Two-fold surveillance is commonly practised: downstream of known potential sources of pollution (control of the efficiency of safety measures) and upstream of abstraction points {in situ protection); the trend is towards diversification of the parameters controlled.

The effect of human activity on the regime and/or quality of groundwater is certain and significant in various cases, but remains nonetheless relatively localised in most countries except for the impact on water quality of diffuse pollution factors such as nitrate influx (due to multiple causes although mainly intensive agriculture) which affect fairly extensive areas. Although already worrying in some zones, the prevailing extent of pollution is less important than the evolutionary trends discernible, which are now being measured in several countries. It is therefore necessary to follow all signs of evolving changes with vigilance, attaching as much importance to the factors themselves as to the results. It is in fact far preferable to promote and prescribe preventive measures than to devise cures.

The slow reaction time of many aquifers retards and perpetuates effects on groundwater regime and quality; it also retards the effects of curative or preventive measures intended to repair damage. These slow reaction times thus defer the effectiveness of such measures, but also prolong the benefits.

CONSEQUENCES OF MODIFICATIONS IN GROUNDWATER REGIME AND QUALITY The most direct quantitative and qualitative consequences are

concerned with groundwater as a resource:

1) Falls in level raise the direct production costs, the energy costs and, below certain depths, the costs of equipment

- 284 -

adaptation. Very substantial falls may impede resource replenishment and induce a disequilibrium regime. More generally, prolonged and ill-advised overexploitation corres­ponds to too many wells or too much pump capacity, and thus to overinvestment. This may lead to a reduction in abstraction in order to restore the dynamic equilibrium to an acceptable level, or to artificial replenishment carried out with the sole aim of maintaining the productivity of in situ equipment. In some cases, however, such induced exploitation of an aquifer may be actively desired and may fall within a conjunctive development plan for groundwater and surface water, this being more advantageous than recourse to a separate alternative resource.

2) Changes in quality also lead to increased treatment costs for drinking water, or impose recourse to other, possibly more costly, sources of supply. More generally, such changes may give rise to a social cost resulting from their diffuse effects on health and on the requirement to increase protective measures. They may also cause economic losses in some sectors of production, either by decreasing yield (irrigation) or by making specific additional treatment processes necessary.

It is, however, necessary to distinguish between increases in cost which represent normal and inevitable consequences of exploita­tion, inherent in the intensification of water requirements and in the general utilisation of water from the natural environment, from increases in cost related to the external effects of other activities which are prejudicial to groundwater users. Only these other activities, together with certain undesirable secondary effects of groundwater exploitation, can be seen in the light of deterioration and depreciation of the resources.

These consequences on groundwater resources are not only appli­cable now but also in the future, and their duration may be prolonged well after the cause has been removed, due to the dynamic inertia of aquifers (particularly unconfined aquifers) and the slow movement of water (particularly in confined aquifers). Some are irreversible. After a period of overexploitation of an aquifer, the time taken to return to an acceptable state of dynamic equili­brium is at least as long as the time of exploitation and may be considerably longer. In particular, deliberate or ill-considered intensive exploitation of relatively non-renewable groundwater storage, the only resource available in many deep confined aquifers, is equivalent to reserving its exclusive benefit to the present generation, to the detriment of future generations (Margat and Saad, 1982; 1983).

Similarly, the spontaneous regeneration of the water in an aquifer by replenishment is a very slow process, and degradation in quality persists for a very long time, often several decades. It has been calculated, for example, that pollution by brines of the shallow groundwater of the Rhine plain in Alsace (France) will only be eliminated between 50 and 100 years after removal of the cause (Duprat et al, 1979).

Modifications in the groundwater regime and/or quality may also affect the surface water resource, both quantitatively and

- 285 -

qualitatively:

1) By a decrease in minimum flow, which both reduces the permanent availability and the powers of dilution and self-purification, in places making it more necessary to regulate the water course by building dams in order to compensate (external cost).

2) By altering the quality of the water from springs and drainage courses, which affects the quality of rivers particularly at low flow.

Either of these factors may seriously affect or even destroy local aquatic ecosystems. Reciprocally, inversions in the exchange of water between river and groundwater caused by intensive exploitation of alluvial aquifers may mean that it will become necessary to conserve quantities and protect the quality of fluvial systems in favour of subordinate exploiters of groundwater.

Other negative environmental consequences brought about by groundwater abstraction are:

1) Subsidence, particularly in conurbations (eg. Berlin in Germany; Denver, Houston, Las Vegas, San Francisco and Tuscon in the USA; Milan and Venice in Italy; Mexico City; London, United Kingdom), ranges between several decimeters and 1 m to 2 m, and even 2 m to 9 m in several cities in California. A total of 42 cases has been described world­wide, including 35 in industrialised countries in Europe, the USA, and Japan, these are the subject of a report prepared by a UNESCO ad hoe working group (UNESCO, 1984, cited in NU/CEE, 1983). Such subsidence affects buildings, urban road systems, water distribution, drainage networks and watercourses. It also affects coastal stability and increases the risks of flooding, it decreases the suitability of land for construction and thus reduces real estate values.

2) Desiccation of the soil resulting from a fall in the level of the water table which previously maintained soil humidity. This causes loss of agricultural production or damage to vegetation. It also increases soil erosion.

Although the consequences of groundwater abstraction are for the most part negative, being manifested by additional costs borne either by water users or other commercial entities (monetary loss or loss of amenities), they may also provide advantages. For example, the falls in water table levels induced by exploitation may be use­ful where there is development of the subsurface, particularly in towns, to such an extent that contemporary rises in the water table (manifested in several countries) which lessen or suppress these external advantages and are the consequence of reduced abstraction or mine drainage, are regarded as a nuisance.

To date there is little economic evaluation of the varied impact of human activity on groundwater. It is commonly limited to financial estimates of the direct extra costs borne by the various users, for example estimates of the cost caused by adherence to preventative constraints for conservation and protection of ground­water used by other operators, or estimation of restorative measures (re-establishment of levels, depollution, etc). The social cost

- 286 -

of damage to this natural heritage is rarely taken into considera­tion: research and development of methodologies would appear to be overdue.

CONCLUSIONS The exploitation of groundwater resources poses three types of

problem: problems of knowledge, problems related to the selection of compatible development and conservation strategies, and problems related to the selection of ways and means of action.

Problems of knowledge include:

1) Knowledge of natural conditions and physical factors relating to the resource, its potential, and its sensitivity. Under­standing of the phenomena which govern the behaviour of groundwater, and reactions to events which affect them in the short or long term, and conversely the reactions of these phenomena to protective countermeasures designed to restore the disturbed regime or degraded quality. The latter is a means of assessing and forecasting the efficacy of pre­ventative measures.

Particular attention should be paid to knowledge of the migration processes of micro-organisms and of toxic or undesirable elements in groundwater, to knowledge of possible spontaneous or induced self-purification processes, to the identification of controlling factors, and to operational simulation of such processes, particularly with the aim of perfecting scientific bases to specify health protection zones already mentioned above.

2) Knowledge of the activities undertaken and of the operators which undertake them. This involves an inventory of abstraction and use, and for activities and environmental transformations having an impact on groundwater, and identification of objectives for activities which use such water or have an indirect effect on it.

3) Knowledge of past situations (retrospective study, definition of reference states), present situations (follow-up), and future situations (forecasting), particularly in zones where groundwater is exploited and/or affected, both quantitatively and qualitatively. Observation of the variation in quantity (levels and discharge) poses fewer technical problems than surveillance of variations in quality factors and indicators. However, the merits of the necessary means must be put forward just as systematically in both cases.

In all cases, it would appear opportune to develop the economy of knowledge, and particularly of sustained knowledge of situations which evolve. The aim of this is:

1) Consciously to adjust the costs of data acquisition (networks for observation of variables) and of the storage and compila­tion of information, to the uses to which such information will be put by decision-makers at various levels, in the short or long term. It is obviously desirable to have such information available before decisions are made (eg. decisions relating to intervention and operations, safety measures,

- 287 -

investment, introduction or tightening of regulations, application of regulations in the context of awarding or cancelling licences).

2) To cast light on the possibilities of fairly distributing such costs (between contributors and beneficiaries).

Finally, there is the problem of informing and educating the public: it is necessary to find appropriate ways and means of disseminating information and of popularising understanding of the nature of this hidden resource.

Problems related to the selection of compatible development and conservation strategies:-

Such problems cannot be dissociated from the definition of a water policy, or a development policy related to land use and occupation, above and below the surface, and of environmental policy:

1) Resource allocation (apportioning between current sectors of use) , both as regards quantity and as regards the water quality required by various users, without excluding energy applications or indirect utilisation resulting from dewatering.

2) Limiting exploitation with a view to preserving a heritage of resources for the future, ie. the continued application of certain conditions to groundwater exploitation.

3) The role played by aquifers in development of water resources in general and the method of exploitation used, particularly by artificially increasing the groundwater phase of the water cycle (artificial recharge, groundwater storage).

4) The restrictions which should be imposed in order to conserve the quantity and protect the quality of groundwater, in the short and long term, and the necessity for arbitration between the objectives of activities that such restrictions aim to protect and those of activities which they might hamper.

5) Restrictions on exploitation of groundwater which should be imposed in order to conserve surface water (a permanent resource and an aquatic ecosystem) or to prevent undesirable external effects on soil stability or humidity.

6) Selection of possible variations in such strategies and in the priority objectives which they imply depending on the condi­tions particular to a given socio-economic unit in a given country. This involves definition of units appropriate to specific groundwater protection policies.

The best way of considering objectives specific to groundwater management and protection is to avoid absolute definition and to integrate such objectives within a general water policy, without dissociating them from the aims of groundwater management within the individual unit. It is necessary to ensure coherence between these objectives and to draw up a hierarchy of priorities, assigning a deliberate place to quantitative and qualitative groundwater protection, and particularly to the security of drinking water supplies. Such a place is already accorded to other economic and social objectives. In other words, it is necessary to see these objectives relating to groundwater in terms of a more general scale of values.

- 288 -

Problems relating to the selection of ways and means :-

Such ways and means enable implementations of the chosen strategy; they include legislative, judicial, statutory, financial, technical and investigatory instruments, which for the most part represent indirect means of intervention.

1) Coherent formulation of such operations and of their proper use; harmonisation of intervention of various kinds, particularly in the case of statutory and financial instruments.

a) If statutory status were to be accorded to groundwater as a unit in the natural water cycle (thus not dissociating it from the status of surface water), taking into account the various conditions under which it occurs either in aquifers or in circulation, this would facilitate more coherent formulation, a more unified approach to protec­tion, and more efficient intervention.

b) Improved coherence is desirable between the regulations relating to groundwater exploitation, the development of surface water, development of the surface and subsurface, and the transport and storage of dangerous substances.

c) It is generally recognised that instruments of economic intervention can effectively complement statutory instru­ments to bring pressure to bear on the operators concerned. Financial inducements in the form of tariff policy, taxation, or subsidies designed to transfer the cost incurred all aim to correct possible distortions caused by differences between the micro-economic motives of individual operators and the collective and general objectives which are the concern of the management authority.

Such financial transfers may correspond to an inter-nalisation of external costs where the funds collected are used to maintain or restore the resource. This might be the case where hydraulic installations prove necessary in order to compensate for the effects of intensive ground­water abstraction on the discharge of a river. Applica­tion, to all actions which cause an alteration in ground­water quality, however diffuse, of the principle that the polluter pays would have the same result and could be used where the resulting damage (to users) is identifiable and reversible and where the cost of restoration is easy to evaluate (by additional water treatment, for example).

It may prove useful to identify clearly the beneficiaries of groundwater protection on the one hand, and those res­ponsible for impairing the groundwater regime and quality on the other. It is then possible to identify the costs incurred by measures taken to protect the resource or repair the damage caused, and to regulate any resulting financial transfers between the entities within the two categories, where these are clearly distinct. The possible respective advantages and disadvantages of indemnifying damage and/or economic loss suffered by bodies

- 289 -

subject to restrictions imposed with a view to groundwater protection remain to be assessed.

2) Distribution and coordination of the powers governing such means of control, and their organisation as a function of the territorial or sectorial competence of the authorities concerned.

The fields of competence of the administrative authorities in charge of groundwater management may be variably equipped to handle complete assessment of the problems involved. This may be true at territorial level as well as at the sectorial level with regard to economic aspects and at the level of control that commonly occurs between separate organisations.

For example, because of the conflicting objectives, the division of groundwater management between administrations concerned with agriculture (as part of the rural environment) and administrations concerned with mining and industry (as a subsurface element) can complicate such control and demote groundwater protection to secondary priority.

This multiplicity of objectives may, like the differences of viewpoint and the disparity in scale of controls, make the preferred policy difficult to apply.

3) Maximum cooperation of the various bodies involved in the selection of the objectives for groundwater conservation, thus facilitating agreement as to the various disciplines and costs involved.

These three types of problem correspond to three functions which should be assumed by more-or-less separate and interconnected services, unevenly distributed between the public and private sectors depending on the country. These functions are as follows: 1) acquisition and distribution bf information; 2) study and fore­casting (assistance in decision-making); and 3) intervention and monitoring of results. Some technical instruments contribute to all three functions (measurement networks, data banks, simulation models). Those which are in public hands are themselves more or less inter­connected with those responsible for identical functions relating to surface water.

Depending on the country, such instruments are either integrated within geologic organisations or administrations concerned with developing the subsurface, or are integrated within hydrologie and water administration services; the two functions may coexist. They are also interconnected or commonly combined with more sectorial (agriculture, industry, health, etc) or more general administrations (scientific research, environmental agencies).

The variety of natural conditions and the multiplicity of agents which exploit, use or influence groundwater, the diversity of methods of exploitation or activity, and the diversity of means of interven­tion in the behaviour of agents all indicate that it is opportune to analyse situations case by case, to differentiate the objectives, and to apply legislative controls with flexibility. Prudent and far-seeing management of groundwater should thus aim to conciliate its conservation as a resource and as an environmental component with concurrent profit of the kind of socio-economic development offered, applying a level of arbitration adapted to each given situation.

- 290 -

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CEC. 1977. Availability of water resources in the European Community. Bruxelles.

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Duprat, A., Simler, L., Valentin, J. 1979. La nappe phréatique de la plaine du Rhin en Alsace. Thèse doct. Univers. L. Pasteur. 266 p. Strasbourg.

Emsellem, Y., Ennabli, M. 1982. L'eau en Méditerranée. Ressources en eau. Utilisations concurrentielles et priorités humaines. NU/PNUE, "Plan Bleu", 2 rapp. fin expertise n°2. Centre Médéas, Sophia-Antipolis.

Jackson, É.E., (Ed). 1980. Aquifer contamination and protection UNESCO Stud. & rep. in hydrology. 29, 123 p. Paris.

Kallergis, G. 1971. Ressources en eaux souterraines, leur mise en valeur, leur protection et leur réalimentation. CEE/Com. probl. eau., Sémin. sur certains problèmes de l'eau en Europe méridionale, Zagreb-Rapport limin., thème D. Wat/SE Sem/D, 1 juin, Genève.

L'Vovich, M.I. 1974. World water resources and their future. Mysl'P.H. Moscow. Engl, transi. A.G.U. Washington.

Mandel, S. 1979. Problems of large-scale groundwater development. Jnl. Hydrol. 43. 439-443. Elsevier, Amsterdam.

Margat, J. 1977. De la surexploitation des nappes souterraines. Colloq. nat. eaux sout. approvis. eau France, Nice. Oct. T II. pp. 393-408. Ed. BRGM. Orléans.

Margat, J. 1982. Exploitation ou surexploitation des réserves d'eau souterraine/Development or overdevelopment of groundwater reserves. UNESCO - Com. nat. Bulg., PHI, Colloq. intern. Calcul bilan eaux sout., Varna, Bulgarie, Sept-Oat. 11p.

Margat, J. and Saad, K.F. 1982. Utilisation des ressources fossiles. Froc. 4ème Conf. intern. Planifie, gestion eaux, CEMPE, Marsailles, Mai. pp. 289-304. Publ. CEFIGRE & BRGM, Orléans.

Margat, J. and Saad, K.F. 1983. Concepts for the utilization of non-renewable groundwater resources in regional development. Natural Resources Forum. Vol. 7. n°4. pp 377-383. UN. New York.

Margat, J. et al. 1984. Eau souterraine et pompes à chaleur Rapp. 64ème Congrès Assoc, gên. hugièn. tec. municip. Clermont-Ferrand, Juin. Publ. Techniques et sciences municipales n°10, Oct. pp. 451-466. Paris.

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- 292 -

Wright, CE. (Ed). 1980. Surface water and groundwater interaction. UNESCO, IHP Work Group 8.3, Stud, and Rep. in Hydrology, 29. 123 p. Paris.

- 293 -

TABLE 1

Abstraction ar.d use of groundwater

Count ry

Austria

Belgium

Canada

Cyprus

Czechoslovak i ;i

Denmark

Finland

France

Federal Republic of Germany

Ce rman Democ rat ic Republic

Greece

Hungary

Ireland

Italy

Luxembourg

Malta

Netherlands

Norway

Poland

Portugal

Rumania

Spain

Sweden

Switzerland

Turkey

USSR

United Kingdom (England S Wales)

USA

Yugoslavia

Date

1975 198 0

1975 198 0

1975 1980

1972

197S 1980

1970 1977

1975 1980

1975 1976-77

1975 1970

1975

1975 1980

1972

1972 1977

1971 1970-75

1979

1970 19 76

1978

1972 19 76 1976

1972

1975 1980

1975 1980

1975

1976

197S

1975

1970 1975

1975 1980

1975 1977

1975 1980

1975 1980

Abstraction of groundwater

Total in 10' m1/year

I of total withdrawal

1.18 4 7 1.17 37

0.67 S 0.68

1.89 '• 7 2.19 ; 5.7

0.4 ' 73

1.13 22 1.22 21

0.72 96 1 .32

0.30 10.6

4.5 19.5 5.45(f) 23.7

S. 74 1 26.3 7.34 I

1.78

1 .68 1 .87

1 .6

0. 126 0.095

9.95 12 12.16

0.03 0.026

0.023

1 .14 1 .04 1 .35

0.055

1.7 2.0

1.8 2.0

1. IS

6.2 4.75

0.4?

0.98

2.0

36

2.39 2.38

114.1 1 15.3

0.83 1 .1

21.4

50 28.3

IS.5

7 . 5

23.3

27.6 33 -

50 45

100

42(g)

5

13.3 11 .9

20 19 |

S ;

li | 11.S j

32.5 !

1' j

9.3 I 10.2 i

23.3 | 17

25 25.3

10 S.7

Allocation o by economic

Public supplies (drinking water)

(b)

0.62 0.6 1

0.41(c) 0.43

0.53 0.58

0.03

0.53 0.60

0.34 0.S3

0.18 0.24

2.0 3.12(c)

4 .35 3.56

J.59

0.19 0.24

0.56

0.009 0.061(c)

2.51 4.76 6.4(c)

0.02 0.013

0 .023

0.46 0.70 0.88

0.01

1 . 1 1 .4

0.70 0.73

0.72

_ 1.1(c)

0.43

0.'2

0."3

10 14

1 .83 1.74(c)

17.6 IS, 6

9.42 0.54

17 groundwater abstraction sector (Id'' raVyear)

Self-supplied industry la)(d)'

u . 50

0.50

0.17 0.17

0.91 1.11

0.01

O.tû 0.40

0.20 0.29

0.04(c)

1 .5 1 .86

4 .39 3.57

0.96

0.05 0.05

0.76

0.06 0.034

St. 4 4

0.66 1 .6

0.01 :i .015

0.63(c) 0.29 0.40

0.07

0.6 0.6

0.46(c)

0.45

O.04

0.38(c)

"

;; 1.11(c) 0.50

33.5(c) j 30.7(c) |

0.35 I 0.46 I

Agiicultu re (e)

0.06 0.06

0.0 3

0.45 0.50

0.36

0.13 0.14

0. 18 0.50

0.09 0.09

1 0.46

0.14

0.23

1 .44 1 .58

0.28

0.01S

6.47 4 .06

. --

0.07

-:

0.70 | 0.7S |

0.01 i

5.64 1

] j

-3 |

S j

0.05 j 0.04 j

66.7 | 68.4 j

0.06 0.10

( ) = see notes at end

- 294

TABLE f (continued)

Propor t ion of groundwater in r e l a t i o n to water volumes used by the main economic s e c t o r s

Public supp l i e s (d r ink ing water) ; (b) (<.)

Se l f - supp l i ed indus t ry ( a ) (d )C . )

A g r i c u l t u r e (e) C )

References

Aust r ia

fiel g ium

Canada

Cyprus Czechoslovak ia

Denmark

Finland

France

Federal Republic of Germany

German Democratic Republic

Greece

liungary I re land

I t a l y

Luxembourg

Malta

Netherlands

Norway

Poland

Portugal

Rumania

Spa in

Sweden

Switzerland

Turkey

USSR

United Kingdom (England S Kales)

USA

Yugoslavia

1975 1980

1975 1980

1975 1980

1975 1980

1970 1977

1975 1980

1975 1976-77

1975 1976

1975 1980

1972 1977

197 1 1970-75

1979 1970 19 76

1972 19 7b 1976

1975 1980

197S 1980

1975

19 76

1975

1975

1970 I97S

1975 1980

1975 1977

1975 I960

1975 1930

12.

100

68

5O/70(c) 91 71

32 32

36 91 93

71/56

100

30(c)

39

71 70

45 45

9.

67

10. 13.

15.

IS

55 50

31

24

10 14

7 3

4

5

1

6.7 5.7

16.

70

32.

15.2 15.7

15. 22

2.2

36

30 30

S 7.7

22

8.6 24

22

22 18.24

22 24

10 24

26 24.26

12

S

8.1 ,

26

( ) * see notes at end

295

TABLE 2

Groundwater discharge and total run-off (total per country)

Country

Belgium

Bulgaria

Canada

Cyprus

Czcchoslovak ia

Denmark

Finland

France

Federal Republic of Germany

German Democratic Rcpublic

Greece

Hungary

Iceland

Ireland

Italy

Luxembourg

Malta

Netherlands

Norway

Poland

Portugal

Rumania

Spain

Sweden

Switzerland

Turkey

USSR

United Kingdom (England & WalesJ

USA

Yugoslavia

Total natural run-off (a) in lO'mVyear

1 2 . 5

205

2901

0.8

90

12.9

113

165

174

17.4

62.9

113.8

66

50

187

5

0.03

90

376

56.2

65.6

2 08

1 10

194

50

173

4 174

120

19 09 2345

244

Average discharge of groundwater in

lO'mVyear

0.9

0.86

3

369.6

0.35

2 . 7

4.3/2.2

1 .9

100-110

37

8.7

2.5 10 12

4.2

24

3.46

23 .3 20.2/12.7

12 0.08

0.03

4.5/1.9

116

36

5.1

8.3/4.5

20.6

6 3

2.7

9.6 + 9

34 0 1040/320

9.8

106 60 0

47

Notes

(b)

(b)

(d)

(c.)

(c)

(f) (c)

(c)

(b)

(b) (d) (f) (b)

(b)

(d)

(c)

(d)

(e)

(c)

(g)

(h) (d)

(c)

(f) (c)

References

22

24

22

H

24

22

10

22

2 4

22

8.4

2 I

26 3

22

4

24 22,24

22,24 10 24 22,24

12

8,22

4

2 2

22

8.2,22

2 6

4

22

22,25

22 S.5 |

I

22 '

22 4

8 . 3 , 2 L i

i ( ) = Refer to notes at end

- 297 -

TABLH 7»

Matrix effeatc of human activity on groundwater

\ Human activity generating impact \ \ \ \

\ • \ 1 \ Î \

\ \ \ \ \ \ \ \

\ ' \ Sensit ive groundwater \ components \

Structure, position and nature of aqui 1 L'V plus boundary character is t ics

i U )

; Pet rophysica I aquifer characteristics : CK, porosityJ

i

! Average level

i Amplitude and regime of fluctuât i on in level

Plow orientation

! Transnii ss ivity (unconfined aquifers)

Rescrvoi r capacity

.Natural inflow

Spontaneous outflow

Phys ical and chemical cha racteris tics of water (quaJ ity parameters)

Direct imp act on groundwatcr

c

ter

2 o ^ o M

a c rt U -a

* c o

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r3

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< X

X

+ (k)

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CO

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cplen

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+-J

u o u

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u o

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+

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o VI

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t _

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r3

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+

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V) O "3 tn — T CÎ

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r + j

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+

r bed

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o u -d

-d i —

rt

ofl

— i

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o o

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1?

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+ Direct c f f c c t (+) Indi roct effect due to the consequence

of given effect on another factor X Possible indirect effect

(a-o) Refers to the notes at the end

298

TA

BU

: 3

(con

tinu

ed)

er

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—

j-

tj

_-a

,_<

a :-i

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ii

^

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tj

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( + )

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--t

4-J

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r: V

,

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d.

nî

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+-• J-

1 M

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p—

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c/;

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--:; o Z

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n o

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u

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4-J

u z •J-,

(+

)

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do re ro

un

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pn

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)

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)

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)

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Î99

NOTES ON TABLES

Table 1

(a) Abstraction for cooling of thermo-electrical power plants may­or may not be included, depending on the country.

(b) Household and public services. Industrial abstraction is excluded unless otherwise indicated (c). Individual abstraction in rural zones is included.

(c) Industrial abstraction from the public network is included.

(d) Abstraction from the public network is excluded unless otherwise indicated (c).

(e) Irrigation, livestock use and fish farming.

(f) Mine dewatering excluded.

(g) Surface water abstraction for saline water flushing (eg. Netherlands) excluded.

Table 2

(a) Sum of natural flow leaving the country, flowing into the sea or into neighbouring countries (sum of flow engendered within the country or possibly imported).

(b) Sum of aquifer replenishment.

(c) Sum of groundwater flow (a component of the total surface flow formed within the country).

(d) Sum of the groundwater flow and the exploitable portion.

(e) Sum of the groundwater flow collected by water courses and of flow going directly into the sea.

(f) Flow of groundwater flowing directly into the sea.

(g) Safe yield (= 60-70% of total replenishment of aquifers in plains) plus average discharge of karstic springs.

(h) Volume actually exploited.

Table 3

(a) Including deforestation and forestation.

(b) Protection against erosion.

(c) Soil conditioning, fertilisers, pesticides, herbicides, biochemical intensification.

(d) Polluting industrial substances or waste.

(e) By pipe or road transport.

(f) Waste or industrial water, salt marshes.

(g) Quarries, mines, underground urban development, tunnels.

(h) Damp-proofing, fortification, foundations.

- 300 -

Table 3 (continued)

(i) Hydrocarbons, brines.

(j) Including at ground level.

(k) Falling.

(1) Rising.

(m) Silting up.

(n) Increase.

(o) Decrease.

- 301 -