The procedure for dealing with new plans or projects or reviews of consents or authorisations likely to affect European marine sites is set out in the Conservation (Natural Habitats &c.) Regulations 1994 and in the Conservation (Natural Habitats &c.) Regulations (Northern Ireland 1995). The two main steps in the process prior to deciding to issue the consent (or to revoke or modify it in the case of reviews) are:

Both of these main steps are the subject of existing or developing guidance to advise both competent authority and statutory nature conservation agency staff on the steps in the process. The role of this Section of the guidance manual is to provide background information on how to use this manual when making a judgement of likely significance and undertaking an appropriate assessment. This Section also illustrates by reference to case studies how information on water quality effects may be used to judge whether an effect is likely to be significant or to have an adverse effect.

In the majority of cases, discharges will contain a mixture of toxic and non-toxic substances and the receiving environment is also likely to contain background levels of toxic and non-toxic substances. Consequently, the effects on organisms are likely to be a result of the combined effects of all of these substances. Combined effects comprise interactions between substances that may enhance toxicity (additive or synergistic effects) and cumulative effects where successive additions of substances in space or time may cause progressive deterioration of a system.

When considering new proposals and reviews of consents and authorisations, it is important that consent conditions are set in the context of all inputs to the system, including other point source discharges, diffuse inputs from the land catchment, atmosphere and surrounding coastal waters and background water quality within the European marine site. It is also necessary to appreciate the influence of the hydrodynamic and physical nature of the system (dilution, retention time, stratification and sediment type) on concentrations and exposure times of toxic and non-toxic substances and to ensure that these are taken into consideration when consent conditions are set. The extent to which these considerations have been taken into account by the competent authority in setting consent conditions should be established by the conservation agency.

Where information is not available or is incomplete for any of these above considerations or when the effects of a substance on organisms comprising an interest feature are not known or are uncertain (appendices B and C), a precautionary approach should be adopted. The precautionary principle or approach in relation to the management of European marine sites should be based on that set out in guidance from DETR (1998). It states that:

'All forms of environmental risk should be tested against the precautionary principle. That means that where there are real risks to the site, lack of full scientific certainty should not be used as a reason for postponing measures that are likely to be cost effective in preventing such damage. It does not, however, imply that the suggested cause of such damage must be eradicated unless proved to be harmless and it cannot be used as a licence to invent hypothetical consequences. Moreover, it is important, when considering whether the information available is sufficient, to take account of the associated costs, including environmental costs, and benefits' (DETR 1998 from ABP 1999). A consideration of the degree to which "no adverse effect on integrity" must be determined absolutely is usefully given in the Cairngorm judgement, (opinion of Lord Nimmo-Smith, 27 October 1998, judgement over Judicial Review petition by WWF UK over development proposals affecting Cairngorm SAC). The relevant extract from this judgement reads as follows:

"There never can be an absolute guarantee about what will happen in the future, and the most that can be expected of a planning authority, as a component authority under the regulations, or of SNH, as the appropriate nature conservation body, is to identify the potential risks, so far as they may be reasonably foreseeable in the light of such information as can reasonably be obtained, and to put in place a legally enforceable framework with a view to preventing these risks from materialising".

Approach to the consenting process

Case studies                     References