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5. CLASSIFYING GROUNDWATER BODIES
5.1 Overview
Protection of our groundwater resources is important to enable their continued use for public and private drinking water supplies, bottled water production and a range of other industrial uses. It is also important for our surface waters and wetlands which depend on the water that reaches them from groundwater.
For groundwater bodies, the approach to classification is different from that for surface water bodies. For each body of groundwater, we are required to classify its chemical status and its quantitative status. Both have to be classed as either 'good' or 'poor'. The WFD sets out a series of criteria that must be met for a body to be classed as good quantitative status and good chemical status. The criteria for good chemical status are further elaborated in the Groundwater Directive.
5.2 The classification process
UKTAG has developed the criteria specified in the WFD and Groundwater Directive into a series of tests as set out in its proposals on groundwater classification. The tests are intended to be applied where a risk is identified to the achievement of the corresponding criteria for good quantitative status or chemical status, and are used to assess whether those identified risks have affected the chemical or quantitative status of the groundwater. Where no risks are identified, a water body can be classed as good status without undertaking the more detailed investigations required by the tests.
SEPA will also be expected to estimate the confidence in its classifications in terms of the level of confidence achieved in the results of each applicable test.
5.2.1 Groundwater chemical status
Five tests are relevant to the assessment of groundwater chemical status. These are summarised in Annex E. The application of the tests is triggered once a relevant risk is identified. The identification of a risk leads to investigations to determine whether or not the criteria specified in the test are met. If the investigations confirm that one or more of the criteria for poor groundwater chemical status specified in a test are met, the body of groundwater must be classed as poor groundwater chemical status. Where no risks are identified, the body will be classed as good groundwater chemical status.
5.2.2 Groundwater quantitative status
Four tests are relevant to the assessment of groundwater quantitative status. These are summarised in Annex F. The application of the tests is triggered once a relevant risk is identified. The identification of a risk leads to investigations to determine whether or not the criteria specified in the test are met. If the investigations confirm that one or more criteria for poor groundwater quantitative status specified are met, the body of groundwater must be classed as poor groundwater quantitative status. Where no risks are identified, the body will be classed as good groundwater quantitative status.
5.2.3 Overall groundwater status
The 'one-out, all-out' principle also applies to groundwater classification; thus overall groundwater status is determined by the lower of the groundwater chemical status and quantitative status classifications. SEPA will be expected to classify the overall groundwater status of each body of groundwater as 'good' or 'poor' accordingly.
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