1 / 26

Alina Meyn, Kenneth M Persson and Bo Leander SWECO, Malmö & Lund university, Lund Sweden

Vulnerability Assessment of Groundwater Aquifers during the Construction of the Citytunnel in Malmö, Sweden . Alina Meyn, Kenneth M Persson and Bo Leander SWECO, Malmö & Lund university, Lund Sweden. The Citytunnel Project. Citytunneln is a rail project Three new train stations

herrerab
Télécharger la présentation

Alina Meyn, Kenneth M Persson and Bo Leander SWECO, Malmö & Lund university, Lund Sweden

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Vulnerability Assessment of Groundwater Aquifers during the Construction of the Citytunnel in Malmö, Sweden  Alina Meyn, Kenneth M Persson and Bo Leander SWECO, Malmö & Lund university, Lund Sweden Meyn, Persson, Leander SWIM20

  2. The Citytunnel Project • Citytunneln is a rail project • Three new train stations • 17 km new track; 6 km two parallel tunnels with single tracks below Malmö; 4.5 km bored, 1.5 km cut and cover construction • Appr cost: 1 B EURO; Ready 2011 Meyn, Persson, Leander SWIM20

  3. Meyn, Persson, Leander SWIM20

  4. Three aquifers Meyn, Persson, Leander SWIM20

  5. Meyn, Persson, Leander SWIM20

  6. Meyn, Persson, Leander SWIM20

  7. Vertical distribution of hydrological flow zones Meyn, Persson, Leander SWIM20

  8. Meyn, Persson, Leander SWIM20

  9. Meyn, Persson, Leander SWIM20

  10. Water balance Meyn, Persson, Leander SWIM20

  11. Meyn, Persson, Leander SWIM20

  12. Meyn, Persson, Leander SWIM20

  13. Actual pumping at Malmö C and Triangeln (September 2005 - March 2008) Qpump 2,7 Mm3 for 907 days, or 1,09 Mm3 per year. Allowed Qpump 400m3/hour not reached. Max 125m3/hour Meyn, Persson, Leander SWIM20

  14. Meyn, Persson, Leander SWIM20

  15. Meyn, Persson, Leander SWIM20

  16. Meyn, Persson, Leander SWIM20

  17. Meyn, Persson, Leander SWIM20

  18. Meyn, Persson, Leander SWIM20

  19. Meyn, Persson, Leander SWIM20

  20. Conclusions • Three main hydrological units: unconfined soil aquifer, upper limestone aquifer and lower limestone aquifer • Separated by barriers. • Hydrological properties, location close to the Sound and low topographic gradient make the aquifers vulnerable to salt water intrusion. Meyn, Persson, Leander SWIM20

  21. Conclusions • During undisturbed (i.e. no contractors present) conditions, flushing of all aquifers takes place • Highest chloride content observed in areas with lowest permeability Meyn, Persson, Leander SWIM20

  22. Conclusions • At some points of Malmö Central station area Cl > than in present seawater • Hydraulic contact with relict saltwater over fissures. • Upconing (pumping for heating and cooling) Meyn, Persson, Leander SWIM20

  23. Conclusions • Citytunnel Project follows strictly the Environmental Permit • Re-infiltration exceed pumping rate at Triangeln • Reached 80% of pumped water at Malmö C. • No visible changes in chloride content of the groundwater at Malmö C area and Triangeln • Some dilution of Cl due to re-infiltration with tapwater at Triangeln • Increase of chloride content at Kung Oskars street. Meyn, Persson, Leander SWIM20

  24. Conclusions • Some flushing / ion exchange at Triangeln Station area • No visible changes in Malmö Central area • Some saltwater intrusion process in Kung Oskar street area. Meyn, Persson, Leander SWIM20

  25. Conclusion • Citytunnel Group managed in general to preserve groundwater level • Flushing/dilution at Triangeln station area. • Some very high horizontal and vertical permeability could still cause salt water intrusion, even if hydraulic head were minimal Meyn, Persson, Leander SWIM20

  26. Thank you Questions, anyone? Meyn, Persson, Leander SWIM20

More Related