1. National Institute for Public Health and the Environment Experiences in the Assessment of Groundwater Chemical Status in the Netherlands Ton de Nijs, Michiel Zijp & Wilko Verweij

2. National Institute for Public Health and the Environment Contents A short introduction to the Assessment of Groundwater Chemical Status Experiences in Implementation Conclusions

3. National Institute for Public Health and the Environment Status Compliance  Dutch Guidance on Chemical Status Compliance

4. National Institute for Public Health and the Environment General procedure to assess a GWB chemical status

5. National Institute for Public Health and the Environment Dutch Guidance Chemical Status Compliance

6. National Institute for Public Health and the Environment Experiences in the Assessment

7. National Institute for Public Health and the Environment Anthropogenic influences on hydrology BlaEu Atlas 1645

8. National Institute for Public Health and the Environment Blaue Kinderdijk

9. National Institute for Public Health and the Environment steam-driven pumping station Ir. D.F. Woudagemaal

10. National Institute for Public Health and the Environment Waterboards Water boards are among the oldest forms of local government in the Netherlands, some of them having been founded in the 13th century. Water boards are charged with managing the water barriers, the waterways, the surface water levels, and the surface water quality in its region.  Currently, the Water boards are not responsible for groundwater but the Provinces

11. National Institute for Public Health and the Environment 1. Water Boards and Provinces

12. National Institute for Public Health and the Environment Collaboration In general, Netherlands is on schedule concerning the implementation of the WFD/GWD, concept River Basin Management Plans are ready. However, collaboration was limited due to: the time constraints imposed on water managers, the historically limited body of knowledge acquired by both sides on the interaction between groundwater and surface water. With the new Water Law in the Netherlands the Water Boards will become responsible for the shallow groundwater Water Boards surface water Provinces groundwater River Basin Management Plan

13. National Institute for Public Health and the Environment 2. Interaction between groundwater and surface water

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15. National Institute for Public Health and the Environment Impacts on threshold values Interaction between ground- & surface water is not well known, especially in the polder areas. A new hydrological model is currently developed including groundwater, surface water and their connections. Assumption in derivation of threshold values: All surface waters are groundwater-dependent  Threshold values of nutrients are defined by the most “sensitive” surface waters within the GWB

16. National Institute for Public Health and the Environment 3. Different starting principles I don’t wanna use that “BRIDGE” method!

17. National Institute for Public Health and the Environment Derivation of Background Levels Since the early 90s Natural Background Levels in the Netherlands are based on:  50 percentile with No Pre-selection EU-Bridge methodology  90 percentile with Pre-selection of stations that are not influenced by human activities In the Netherlands: EU Bridge method: 95% lower limit NBL = Highest Value of Two Methods  More conservative Natural Background Levels

18. National Institute for Public Health and the Environment 4. Is it natural or anthropogenic?

19. National Institute for Public Health and the Environment Arsenic in Dutch sediments Locally high levels of Pyrite and Bog Iron As is released when redox conditions change because of changes in groundwater flow due to: -Natural: Tidal movements or -Anthropogenic: Lowering of groundwater level or infiltration of NO 3 -

20. National Institute for Public Health and the Environment 5. Absence of supporting environmental criteria for terrestrial ecosystems

21. National Institute for Public Health and the Environment Terrestrial ecosystems are solely defined by the abundance and composition of the biological elements and habitat types Aquatic ecosystems are defined by composition and abundance of biological elements but also by their supporting hydro-morphological characteristics, nutrient levels, transparency, acidity and river flow;  Additional supporting criteria for terrestrial ecosystems should be defined to secure the presence of specific species or habitat types including: nutrient conditions, acidity, salinity, groundwater level and other relevant physical/chemical parameters

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23. National Institute for Public Health and the Environment Conclusions First, the Netherlands is on schedule concerning the implementation of the WFD/GWD: concept River Basin Management Plans are ready. -Integrated management of ground- and surface water will improve once the Water Law has been passed; -Lack of knowledge on the interaction between surface and groundwater. A new hydrological model is being developed; -Relative conservative background levels and threshold values; -Sometimes it is hard to distinguish natural and anthropogenic processes; -Supporting environmental criteria are needed for the terrestrial ecosystems.

24. National Institute for Public Health and the Environment For more information: www.rivm.nl Contact: e-mail: ton.de.nijs@rivm.nl Questions?