The determination of significance

Where there is an imminent threat of environmental damage or the immediate management of damage factors is necessary, a rapid assessment of potential significance must be completed based on readily available information. As such the assessment may largely be based on reasonable belief around general information about the damage factors, natural resources or services and the adverse effects. Where environmental damage has occurred, and remedial measures are required, a more detailed and site-specific assessment should be completed for the design of remedial measures.

Assessment of environmental damage is made relative to a baseline condition. The baseline condition is defined in ELD as “the condition at the time of damage of the natural resource and services that would have existed had the environmental damage not occurred, estimated on the basis of the best information available”.

The EU COM Notice states that significance must be “determined in relation to the actual physical area of land or water or (in the case of protected species) actual populations adversely affected or at risk of being affected, taking account of any pre-existing intrinsic characteristics or dynamic factors that may have been influencing the natural resources concerned independently of the damaging occurrence” ¹. To this end, the Notice outlines the geographical scale to which the ELD applies for protected species and natural habitats must be meaningful at local level, and for water damage is the waters which have been adversely affected.

With respect solely to protected species and natural habitats, it is important to note that Annex I of the ELD includes reference concepts for adverse effects which, at the discretion of Member States, do not have to be determined as significant. These concepts relate to short term adverse effects which are smaller than natural fluctuations, or resulting from normal management of a site, or where a protected species or natural habitat will recover within a short period of time.  These discretions should be interpreted strictly when assessing whether damage is significant or not ¹.

The definition of water damage in the ELD speaks to a significant adverse effect on the status, as defined in the Water Framwork Directive, on the “waters concerned”. The Notice states that the waters “concerned” are those affected by damage¹. Therefore, the determination of environmental damage is not limited to the geographical scale of a waterbody as delineated under the Water Framework Directive. The area where adverse changes are experienced may extend across several of these waterbodies, or may concern only part of a waterbody². However, in some cases, it may be appropriate to apply the ELD to a delineated waterbody, for example, when the reference concept of relevance is the quantitative status of a groundwater body, where that groundwater body acts as a distinct hydrogeological unit for that purpose.
The status of waterbodies under the WFD is assessed every 6 years.  The ELD necessitates a shorter-term identification of a significant adverse effect³ and is not tied to this 6 yearly cycle, with the Notice stating that adverse changes will be significant where there is a measurable gap between the time when the adverse change occurs and the baseline condition is restored⁴. 
From the above it is clear that for an adverse effect to be considered significant, it is not necessary for a change in classification for the purposes of the Water Framework Directive to have occurred – though a change to a lower status classification may be a significant adverse effect requiring action under the ELD⁵.