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Groundwater Protection in Selected Countries

6. Discussion

Selecting the most appropriate groundwater protection strategy for a country can be difficult. This protection strategy is a kind of statement of the country‘s level of ambition. It is the implementation of the strategy, however, that provides the actual protection.

The level of ambition of most industrialised countries has been to maintain/return all groundwaters to their beneficial uses or functions resulting in the multifunctionality of groundwater. This approach poses enormous financial problems. A lower level of ambition is to focus on treatment of contaminated groundwater prior to use rather than to be concerned about groundwater protection. This approach may lead to the rapid degradation of the quality of groundwater. Neither of these approaches is necessarily appropriate.

Below, several groundwater protection strategies are discussed to illustrate the challenges which can be involved. Following the strategies, a number of open questions suitable for discussion are listed.

6.1 Multifunctionality strategy

In this approach, the level of ambition is to maintain/return all groundwaters to multifunctionality. For the sake of argument, this approach is here carried to its extreme.

No aquifer distinctions

In this approach, no distinction is made regarding the value of the resource. An aquifer with inferior natural quality, low yield, or a location in a sparsely populated region is treated equally with more valuable resources. The basis for this lack of distinction is the precautionary principle. The most cautious approach is to ensure that the entire resource is protected, since it is not possible to accurately predict the demographics and water needs of the future.

Straight-forward approach

An advantage of the multifunctionality approach is that it is very straight-forward. Since there are no distinctions made between cases, there is very little risk of a polluter being able to lobby his way out of liability or of an environmental authority to carry out a vendetta against one specific polluter.

Clean-up methods limited

The criteria which must be used for the remediation of contaminated sites in this approach are necessarily criteria based on health effects with an adequate safety margin. No allowances can be made for using alternate criteria. This favours certain remediation techniques over others, regardless of price. For example, traditional excavation of contaminated soil is preferable over in-situ techniques, which are unable to meet the most stringent clean-up criteria.

Expensive approach

A major disadvantage to this method is the high cost involved. Whether or not these costs are warranted is a political question and will not be discussed here. The fact is, however, that current budgets typically are inadequate for this approach.

Implementation vacuum

When an adequate budget is lacking, it is naturally very challenging to implement the protection strategy. If the strategy designers have not predicted this situation, an "implementation vacuum" can easily arise. In this vacuum, no guidance is given in how to proceed in the case when the stated level of ambition can not be met with the funds provided. This can result in large regional disparities of approach, as each authority is left to implement in the way they see best fit. In Denmark, for example, some regional authorities give contaminated sites which threaten land use the highest priority for remediation, while other regional authorities focus on groundwater threats. In all fairness, this "implementation vacuum" can also be considered an intentional decentralisation of decision-making.

To fulfil this vacuum, the Environmental Protection Agency (EPA) in the USA often takes a direct approach by recognising areas in which compliance to stated ambition levels may be difficult or impossible and proceeding to describe less ambitious goals. For example, the EPA states,

" [Superfund] program experience has shown that removal of DNAPLs [dense non aqueous phase liquids] from the subsurface is often not practicable, and no treatment technologies are currently available which can attain ARAR [standards] or risk-based cleanup levels where subsurface DNAPLs are present. Therefore, EPA generally expects that the long-term remedy will control further migration of contaminants form subsurface DNAPLs to the surrounding ground water and reduce the quantity of DNAPL to the extent practicable." (USEPA, 1996).

6.2 Water treatment strategy

In this approach, the level of ambition is limited to avoiding significant contamination of surface waters, while no attempt to avoid groundwater contamination is made. Instead, focus is placed on the treatment of abstracted groundwater prior to use.

Psychological barriers

This strategy is associated with significant psychological barriers. Few of us feel that proper stewardship of our natural resources can include an approach where no reaction is taken towards contamination. It would appear that this strategy does not encompass the goal of sustainability, since the state of the groundwater resource will deteriorate with time. It can also be argued that this strategy is not in keeping with the precautionary principle, since all of the consequences may not be apparent at this time.

Treatment methods exist

However, is can be difficult to argue that this approach is impossible. Advanced water treatment techniques do exist which are capable of removing all kinds of contaminants, even though the methods may be difficult to operate properly, may be expensive and may lower the quality of the water. These methods include adsorption on activated carbon or other materials, stripping, precipitation, biological degradation, ion exchange, neutralisation, etc. If no other technique exists for a specific compound, various membrane filtering techniques such as reverse osmosis can often be used.

Expensive approach

This strategy involves increased expense with respect to water treatment. However, since groundwater protection is unnecessary, decreased expenses with respect to investigation multifunctionality and water treatment strategies and no attempt is made here.

Robust criteria

A prerequisite for this strategy is that robust criteria for treated water must be set. Since increasing numbers of contaminants must be treated in this approach, these contaminants must be adequate to ensure that the criteria are observed.

Figure 6.1:
Milestones and pathway in the combined groundwater protection strategy

A combined strategy includes elements from the multifunctionality strategy and the water treatment strategy. One possible combined strategy is described below.

Aquifer value

A key element in the combined strategy is the differentiation of groundwater aquifers according to their present value and perceived future value. Aquifer value is related to the population density in the vicinity, the natural groundwater quality and the sustainable yield of the aquifer. Aquifers with high value can subsequently be prioritised higher than aquifers with low value. In the United States, differentiation of aquifers is left up to the individual states, resulting in state variations in the approach to groundwater protection.

Aquifer vulnerability

The combined strategy also includes a determination of aquifer vulnerability. There a various methods of carrying out this determination. In England, much focus has been placed on aquifer vulnerability and maps on a scale of 1:100,000 have been prepared for the whole of England and Wales. The maps are based on the two major parameters, geological classification and soil classification. Additional parameters which could be included in the determination of vulnerability include hydrogeology and groundwater chemistry. Use of mapping with geophysical techniques is of great value here.

Maps of aquifer value and vulnerability are then overlaid to determine critical areas with respect to groundwater protection.

Prioritising sites

In the combined strategy defined here, all contaminated sites are identified and listed, without reference to aquifer value or vulnerability. The listed sites are then divided into two categories: those falling within the critical areas, and those in less critical areas. This initial prioritisation determines which sites must be investigated. Following investigation, a new round of prioritising must take place to determine which sites are to be remediated first. This second prioritisation is based on a risk assessment or scoring system.

Setting cleanup criteria

Prior to remediation, it is necessary to determine cleanup criteria. This can be done in a number of ways. One extreme is to simply use drinking water standards or to require the use of best available technology. A second method is to outline various remedies, the costs involved and the criteria which are expected to be reached. In this way, the criteria are related to the remediation technology selected.

Use of contaminated water

In many cases, remediation of contaminated groundwater takes place with the pump-and-treat technique. Treated water is often discharged to a surface water body. Alternatively, other uses (such as industrial uses) could be made of this water in order to reduce the amount of pristine groundwater which must be abstracted and hereby conserve the groundwater resource.

Groundwater protection strategies can be visualised by a flowchart which shows the major milestones and the pathways between these milestones. Figure 6.1 shows a flowchart for the combined strategy described above.

Further discussions will undoubtedly reveal new insight into the question of groundwater protection strategy as it relates to point sources of contamination. The following list of questions are intended to provide a starting point for ensuing discussions.

In this report, a number of legislative, technical and implementation milestones were identified. These milestones can be used to determine the status of a country’s groundwater protection program. Questions: Have any milestones reached 100% completion? Have any of the milestones identified not yet been addressed?

It can be argued that there is a great disparity between legislation and implementation. What appears to be appropriate legislation may be in place, but implementation of the legislation appears to be permanently stuck in the initial phases. Question: Can specific examples of this phenomenon be identified?

International literature is full of estimates as to how long a remediation programme will be necessary in order to clean up the contamination problems of the past. Initially, these estimates were relatively short, often around 10 years. As we learn more, these time estimates tend to lengthen. Question: Are remediation programmes for point sources a permanent part of our society?

Groundwater protection strategies have changed through the years. As an example, hydrocarbon contamination was previously thought to be one of the very greatest threats to the groundwater resource. Currently, recalcitrant contaminants such as chlorinated solvents and pesticides are in focus while hydrocarbons are thought to present only local threats. Question: Is there any value in a long-term strategy, or must a strategy be reactionary, such that when new information is available, a new strategy is prepared?

Decision-making in relation to contaminated sites, water supply and groundwater protection can be made at various levels. Many countries make decisions about these subjects at the regional, local and national scales, respectively. Questions: Should groundwater questions be administered on an aquifer basis rather than the typical political boundaries? Should sites which threaten groundwater and sites which threaten land use be administered separately?

A combined strategy for groundwater protection is described in a general way in section 6.3. Question: Is there a need to develop a detailed paradigm of this strategy at an international level?

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