CHAPTER IV. Environmental aspects of water management
IV.3. Protection of groundwater
a) Groundwater chemical status
Groundwater chemical status depends on a large number of variables. These include:
- human pressures, such as
- diffuse and point sources of pollution,
- abstraction, artificial recharge, alterations to the recharge characteristics such as rainwater and run off diversions, sealing, drainage, damming, irrigation to the extent they influence the chemical composition of the groundwater body;
- the general character of the overlying strata in the catchment area;
136 Art. 4.7 ibid.
137 Art. 13.3 (e), WFD.
138 See Section VI.3 below.
139 Section 2.1., Blueprint.
140 EUROPEAN COMMISSION (2015): Ecological flows in the implementation of the Water Framework Directive, CIS guidance document No. 31, Luxembourg.
- connection to surface water or dependent terrestrial ecosystems141. Groundwater chemical status is regarded as “good”, if
- the chemical composition of the groundwater body does not exhibit the effects of saline or other intrusions;
- the concentration of pollutants
- do not exceed the applicable groundwater quality standards defined by the so-called Groundwater Directive142;
- will not result in
- a failure to achieve the environmental objectives of associated surface waters,
- any significant diminution of the chemical or ecological quality of such water bodies,
- any significant damage to terrestrial ecosystems which depend directly on the groundwater body;
- changes in groundwater conductivity do not indicate saline or other intrusions143. In any other cases groundwater chemical status is considered to be “poor”.
The provisions of the WFD on the assessment and classification of groundwater status are supplemented by the Groundwater Directive. It defines uniform groundwater quality standards for nitrates, active substances in pesticides, degradation and reaction products144. The concentration of these pollutants must not be exceeded in order to protect human health and the environment. In addition, the Groundwater Directive also calls for the establishment by member states of threshold values for groundwater bodies that have been identified as being at risk of not meeting good groundwater chemical status. The relevant substances include Arsenic, Cadmium, Lead, Mercury, Ammonium, Chloride, etc.145
b) Control of inputs: general requirements
The fundamental obligation of member states relative to groundwater quality management is the prevention or limitation of the input of pollutants into groundwater (inputs refer to direct and indirect introduction of pollutants into groundwater as a result of human activity).
The relevant control measures under the WFD and the Groundwater Directive include:
- the prevention of inputs into groundwater of any hazardous substances;
141 Annex II.2, WFD.
142 Directive 2006/118/EC of the European Parliament and of the Council of 12 December 2006 on the protection of groundwater against pollution and deterioration.
143 Annex V.2.3, WFD.
144 Annex I, Directive 2006/18/EC.
145 Annex II ibid.
- for non-hazardous pollutants all measures necessary to limit inputs into groundwater so as to ensure that such inputs do not cause deterioration or significant and sustained upward trends in the concentrations of pollutants in groundwater146.
The two directives, however, provide for a wide range of exemptions from this rule. These include:
-
authorisation of direct discharges for-
reinjection into the same aquifer of water used for geothermal purposes;-
injection of water containing substances resulting from various mining activities;-
injection of natural gas or liquefied petroleum gas for storage purposes;-
injection of carbon dioxide streams for the purposes of carbon capture and storage;-
construction, civil engineering and building works and similar activities on, or in the ground which come into contact with groundwater;-
discharges of small quantities of substances for scientific purposes for characterisation, protection or remediation of water bodies limited to the amount strictly necessary for the purposes concerned147;- inputs of very small quantities and concentrations with no danger of deterioration of groundwater quality;
- the consequences of accidents or exceptional circumstances of natural cause that could not reasonably have been foreseen, avoided or mitigated;
- the result of authorised artificial recharge or augmentation of bodies of groundwater;
- inputs whose control is technically impossible without risk to human or the environment or without disproportionate costs;
- inputs resulting from flood and droughts control or the management of waters and waterways (cutting, dredging, relocation and deposition of sediments in surface water, etc.). However, none of such inputs may compromise the achievement of the environmental objectives of the WFD148.
c) Reversal of significant and sustained upward pollution trends
Member states are not only required to prevent or limit existing and future inputs of pollutants.
They are also required to monitor historic or on-going pollutions and reverse any significant
146 Art 6.1-2, WFD.
147 Art 11.3.j) ibid.
148 Art 6.3, Directive 2006/18/EC.
and sustained upward trends in order progressively to reduce pollution of groundwater149 (significant and sustained upward trend means any statistically and environmentally significant increase of concentration of a pollutant, group of pollutants, or indicator of pollution in groundwater for which trend reversal is identified as being necessary)150.
The obligations of member states relating to significant and sustained upward trends in the concentrations of pollutants are as follows:
- identification of significant and sustained upward trends in groundwater bodies being at risk of non-compliance;
- definition of the starting point for reversing the trend;
- reversal of those upward trends that present a significant risk of harm to the quality of aquatic ecosystems or terrestrial ecosystems, to human health, or to actual or potential legitimate uses of the water environment151.
d) Control of discharges from industrial installations
As in the case of surface water, inputs of pollutants into groundwater by large industrial installations are also subject to the Industrial Emissions Directive (IED)152.
In addition to the general water discharge requirements summarised above, the integrated permits must contain appropriate requirements:
- ensuring protection of the soil and groundwater;
- for the regular maintenance and surveillance of measures taken to prevent emissions to soil and groundwater;
- for the periodic monitoring of soil and groundwater in relation to relevant hazardous substances likely to be found on site and having regard to the possibility of soil and groundwater contamination at the site of the installation153.
In addition, the IED also provides for the periodic (5 year) monitoring of groundwater status and the removal of hazardous substances from groundwater upon the definitive cessation of the industrial activity154.
e) Control of nitrates pollution from agriculture
As mentioned above, a significant objective of water policy is the control of nitrogen pollution by agriculture155. Although the prime recipients of nitrates pollution are groundwater bodies, the Nitrates Directive does not set up a specific groundwater protection regime, but integrates the subject into the general framework of nitrates pollution management:
149 Art 4.1.b)(iii), WFD.
150 Art 2.3, Directive 2006/18/EC.
151 Art 5.2 ibid.
152 See Section IV.2.1.e) above.
153 Art. 14.1, Directive 2010/75/EU.
154 Art. 16.2 and 22 ibid.
155 See Section IV.2.1.g) above.
- the identification of groundwater bodies that contain more than 50 mg/l nitrates or could contain more than 50 mg/l nitrates if action is not taken;
- the designation of nitrate vulnerable zones comprising areas of land which drain into polluted waters or waters at risk of pollution and which contribute to nitrate pollution (alternatively, they may designate the entire country as vulnerable)156;
- the introduction of codes of good agricultural conduct to be implemented by farmers on a voluntary basis157;
- the establishment of action programmes to be implemented by farmers on a mandatory basis. These action programmes, in addition to those contained in the codes of good conduct, may include limitation on the application of certain fertilisers, the installation of storage vessels for livestock manure, etc.158
IV.3.2. Groundwater quantity management a) Groundwater quantitative status
The WFD considers the qualitative (chemical) and quantitative dimensions of groundwater status on an equal footing. Quantitative status is an expression of the degree to which a body of groundwater is affected by direct and indirect abstractions. Against this background “good quantitative status” is defined with reference to a number of generic indicators as follows: the level of groundwater in the groundwater body is such that the available groundwater resource is not exceeded by the long-term annual average rate of abstraction. Accordingly, the level of groundwater is not subject to anthropogenic alterations that would result in:
- failure to achieve the environmental objectives specified for associated surface waters, - any significant diminution in the status of such waters,
- any significant damage to terrestrial ecosystems which depend directly on the groundwater body,
- alterations to flow direction resulting from level changes that may occur temporarily or continuously in a spatially limited area, provided that such reversals do not cause saltwater or other intrusion, and do not indicate a sustained and clearly identified anthropogenically induced trend in flow direction likely to result in such intrusions159. b) Control of groundwater quantity
The starting point of the management of groundwater quantity is the general obligation of member states to ensure a balance between abstraction and recharge of groundwater, with the aim of achieving good groundwater status160. This horizontal duty is broken down to a number of measures concerning the abstraction and recharge of groundwater. These include:
156 Art. 3, Directive 91/676/EEC.
157 Art. 4 ibid.
158 Annex III, Directive 91/676/EEC.
159 Annex V.2.1.2, WFD.
160 Art 4.1.b)(ii) ibid.
- identification of groundwater bodies used for drinking water abstraction161;
- prior authorisation and registers of abstraction of groundwater (except for abstractions with no significant impact on water status)162;
- prior authorisation and other controls of the artificial recharge or augmentation of groundwater bodies. The water used for these purposes can come from any surface water or groundwater, provided that this does not compromise the achievement of the environmental objectives established for the source or the recharged or augmented body of groundwater163.