WGC-2 DG Meeting Towards a Guidance on Groundwater Chemical Status and Threshold Values

1. WGC-2 DG MeetingTowards a Guidance onGroundwater Chemical Status andThreshold Values 14:00 – 16:00 21 April 2008 Ljubljana, Slovenia

2. Towards a Guidance on Groundwater Chemical Status and Threshold Values • Status of document • Status assessment and TV establishment merged; • Accepted by SCG (7 Nov 2007) as interim version; • Available at CIRCA • In general: positive feedback on the „merged version“ •  objective: finalise and agree document

3. Chemical Status and Threshold valuesTowards a guidance… Comments received so far and proposed amendments • 3 para, section 4.8: text might imply that DW standards must be met in GWB (ES, Euromine) • Para will be deleted as it refers only to 7.2 WFD • Better refer to final directive on priority substances and include footnote on the draft status (Euromine) • The reference to the (draft) Priority Substances Directive will be refined until June • AF & DF: don‘t advise MS not to apply the best approach (Euromine) • It is not obligatory to include dilution and attenuation in the TV derivation approach. To calculate DF and AF requires a good understanding of the groundwater system and the groundwater-surface water interaction and sufficient confidence in the conceptual models used (see Annex 1). If such an understanding is lacking, it is recommended that dilution or attenuation factors are not used.

4. Chemical Status and Threshold valuesTowards a guidance… Comments received so far and proposed amendments • 5 para, section 4.4: Grouping of bodies not according to monitoring results (IE) • Proposal: ..."Where monitoring results show that there is an exceedance at one or more monitoring sites, the conceptual model for the group should be reviewed to ensure it can still be applied to all bodies in the group. If the rationale for grouping the groundwater bodies is confirmed, the status of the individual bodies can be considered to be the same and there will be no need to split the group. If this is not the case, the grouping needs to be reviewed and the proposed tests applied accordingly.“

5. Chemical Status and Threshold valuesTowards a guidance… • Section 1, last para (NL) The methodology for setting threshold values and assessing the status of groundwater bodies developed in this document aims to support Member States in meeting the minimumrequirements of the GWD when assessing groundwater body status for the WFD and GWD. Member States are free to adapt the guidelines presented in this paper in view of the characteristics of groundwater bodies and/or national or regional groundwater management strategies and regulations. Furthermore, it is to be expected that after practical experience of setting threshold values and assessing the status of groundwater bodies, improved methodologies will emerge.

6. Chemical Status and Threshold valuesTowards a guidance… Comments received so far and proposed amendments • Step 3, section 4.4: questioning 20 % (IE) • The 20 % criterion as a trigger of further investigations for status assessment shall remain in the guidance; the reasons for 20 % should be explained • The 20% criterion is considered as a default criteria – depending on the particular situation in the GWB and on the monitoring network a different percentage may be selected or an alternative approach for determining the extent of exceedances used. An explanation and description of the applied methodology should be summarized in the RBMP. • Comments on TVs & Epsilon (DE) • epsilon” will be removed from Figure 4 and from the text. • In the text the possibility for adding a certain concentration to the background level for the TV will be described (keeping the principles of epsilon). (For non-hazardous substances the “limit inputs” gives an argument for epsilon). • Reminder: respect WFD obejctives and receptors protection

7. Chemical Status and Threshold valuesTowards a guidance… removed

8. Chemical Status and Threshold values Towards a guidance… Further comments and proposed amendments • Need of 2 types of TVs or just 1 TV? TV for relevant receptors? (NL) • “RELEVANT” ecosystems to be considered for the assessment of GW status – hence, relevant TV to be derived? • Proposal: Relevant ecosystems to be considered for the assessment of GW status and the establishment of relevant TVs are ecosystems according to Natura 2000 and other GWDT ecosystems with sufficient ecological and socio-economic value if damage is regarded as significant (dependent on its severity) [‘Wetland Guidance’ p22ff] • Period for calculation of mean values • Proposal: As a rule 2 years, which makes it possible to calculate an average value even if only 1 measurement per year is taken. A longer averaging period (up to 6 years) may be chosen where the conceptual model and monitoring data indicate a need to avoid the influence of short-term variations in quality that do not indicate the real impacts of pressures. • Editorial remarks • Exchange ‘recharge-pathway-discharge’ by ‘flow conditions’

9. Chemical Status and Threshold values Towards a guidance… • Case studies – • The Netherlands – TVs • Germany – TVs • Eurogypsum – background level sulphate • Way forward • Presentation of amendments to WG C • Finalizing Guidance based on comments • Complementing with case studies – please check, whether the case studies are in line with the guidance • Case studies until end June • ….. • Distribution of amended draft to drafting group and WG C