Managed Aquifer Recharge (MAR) for coastal aquifer management in a changing climate

1. Managed Aquifer Recharge (MAR) for coastal aquifer management in a changing climate Water4Coasts Hinsby, K., Johnsen, A.R., Jacobsen, C.S., Sørensen, S.R. and Postma D. 1Geological Survey of Denmark and Greenland, GEUS, khi@geus.dk 8th annual meeting of the Danish Water Research and Innovation Platform – DWRIP - January 30th, 2014, KU Science, Frederiksberg, Copenhagen

2. Outline • Global challenges on coastalaquifer management in a changingclimate • Location and introduction to ”Water4Coasts” studysites • Partners and funding of the Water4Coasts project • Main threats for the Brazilian, Chinese and Danish studysites • Managed aquiferrecharge (MAR) – a possible solution? • Objectivesof the Water4Coasts project • Preliminary results from the Danish study site

3. Water4Coasts/sites and issues Seawater intrusion Flooding Falster, Denmark Eutrophication / algalblooms / fishkills Laizhou bay, China Overabtraction and watertabledecline Recife, Brazil Land subsidence

4. Partners: Brazil: Fed. Univ. Pernambuco, Recife; Fed. Univ. Rio de Janeiro China: China Geol. Survey (CGS – Tianjin Center), Univ. Nanjing Denmark: GEUS; Univ. Aarhus; Univ. Roskilde,Grontmij/COWI, Sorbisense, Hydroinform

5. Water4Coasts funding • Funding 50 % by the Ecoinnovation program of the Danish Ministry of Environment/ EPA - 50 % by partner institutions • China and Brazil fund own case studies but receivesmall fundingfor monitoringdevices from Danish EPA. • 2 Year project – three case study sites

6. SWI study site in Brazil, Recife. Brazilstudy site Recife Rio dJ

7. Recife and Rio de Janeiro settings, Brazil

8. Recife situation – evaluation of injection of harvested rainwater for SWI control Copenhagen, June 2013

9. Rain harvesting and injection into seawater intrusion barriers – a potential solution? experiment Copenhagen, June 2013

10. SWI study site China, Laizhou Bay Beijing Tianjin China study site / Laizhou Bay

11. Shallow aquifer at Laizhou Bay Relationship between precipitation, groundwater extraction and depth to water table Shallow groundwater level curve

12. Remote sensing Airborne SWI Monitor system Physiognomy Surface Soil Rivers Under- ground Physical chemistry of water in well Apply and test new innovative and efficient monitoring, data handling and visualisation techniques Hubert de Jonge (director of ”Sorbisense” www.sorbisense.com) demon-strate the passive sampler ”SorbiCell” for time and flow averagedmonitoring of e.g. organicmicrocontaminants and nutrients Data handling and visualisaton Testing new and less expensive on-line chloride and nitrate sensors

13. The Island of Falster – measures to reduce seawater intrusion, flooding risks and eutrophication DWS Sweden Baltic Sea / salinity ~ 10 %o Denmark Copenhagen Island of Falster Germany Poland www.baltcica.org

14. MAR in coastalaquifers – and the principleof seawaterintrusionbarrier to controlseawaterintrusion Most experience and known examples in California (from the early 50’s) and Spain. After Sheahan, 1977 (Ground Water)

15. Water4Coasts objective: To evaluate possible measures for reducing seawater intrusion (SWI) etc., and new innovative tools for groundwater quality monitoring, data handling and visualisation • Evaluate feasibility and effect of hydraulic barriers to control SWI (quantity and quality issues) • SEAWAT Model assessments of the efficiency of different hydraulic barrier designs to reduce SWI (vertical vers horisontal wells / injection vers. abstraction) – as well as travel times to water supply wells • Feasibility study of using recycled water and/or harvested rainwater for managed aquifer recharge / MAR to control SWI (quality issues e.g. Org. microcontaminants, pathogens, oxidation/mobilization of trace elements and clogging by PhreeqC) • Develop and evaluate new innovative monitoring, data handling and visualisation techniques

16. SEAWAT model evaluation of injection of drainage + recycled water into vertical and/or horisontal SWI barrier wells to reduce SWI, flooding and eutrophication risks In Well field 3 Waste Water Treatment Plant Well field 2 Drainage + recycledwater seawater intrusion barrier Sampling sites in drain chanel Water Works Pumping Station Well field 1 100 and 25 m deep investigation wells 1 km

17. 93 pharmaceutical compounds Outlet from treatment plant – 31 finds, 19 above proposed DWS

18. Pharmaceutical compounds The sum of all finds is > 34 times a groundwater quality standard which was recently unofficiently suggested by the German EPA

19. Potential inorganic reactions to be considered - when injecting oxic recycled water to anoxic aquifer: Positive effects: Reduction of oxygen and nitrate (denitrification) by pyrite and organic matter – sorption of dissolved P. Negative effects: Release of trace metals (Zn, As, Ni?+) by pyrite oxidation, however probably sorbed to precipitating Fe-hydroxides -> clogging? (redox env. And pH need to be controlled and monitored) Neutral effects (potentially neg.): Ion exchange Ca <-> Na and freshening

20. Preliminary conclusions • The quality of the water in the drainagecanals/ ditches in the Danish test site is poor due to quitehighcontents of pharmaceuticals and pathogens and requiresefficienttreatmentbeforeaquiferrecharge. • Future research on the transport and fate / travel times of pharmaceuticals and pathogens in (fractured) aquifers and in the aquaticenvironment in general is stronglyneeded • Cost-efficient screening and treatmenttechnologies for pharmaceuticals in recycledwater is stronglyneededin order to make managed aquiferrecharge systems with recycledwater more widelyaccepted.

21. 多謝 – Thankyou