On fresh-saline groundwater in deltaic areas


leaflet fresh-saline groundwater Deltares



    Salinisation causes problems for farmers, water managers and nature in many coastal areas of the world. Deltares has in-house databases, numerical modelling techniques, monitoring tools and the knowledge to thoroughly investigate salinisation issues and to implement innovative solutions for a robust climate proof fresh water supply in the coastal zone.

    Threats to fresh water resources

    Permanent groundwater drainage keeps the polder areas sustainable in a large part of The Netherlands accelerate due to the anticipated sea level rise, climate change, future land subsidence and especially due to human factors like groundwater extraction and lowering of differentiated polder water levels. The processes described here for the Dutch situation prevail in many other deltas and coastal areas. Concluding, not taking any mitigation and/or adaptation measures will lead to a world-wide increase of salinisation.

    Focus on regional and local processes

    Deltares researchers investigate the processes of fresh, brackish and saline groundwater on different scales. On a regional scale, the effects of climate change, land, and water use change and the combined effects of preventive measures on groundwater salinisation are studied. Other studies give answers on how groundwater concentration changes affect surface water quality. On a local scale, the dynamics of fresh rainwater lenses on saline groundwater as a result of natural or artificial recharge are studied. These lenses allow agriculture where shallow groundwater is very saline. Other research topics are preferential groundwater flow via sandy layers and boils that connect deep saline aquifers with shallow aquifers and with fresh surface water bodies. These preferential flow paths largely contribute to the salinisation of Dutch low-lying areas. Our knowledge is not specific for the Netherlands and can be applied in similar deltaic areas around the world.

    Solutions of salinisation problems

    Deltares has the knowledge and expertise to study processes in combined fresh and saline groundwater systems. We develop and apply monitoring tools and techniques like the T-EC probe, EM-Slimflex and other online real-time measurement techniques. Moreover, Deltares has the modelling experience and the numeric compute codes (like MOCDENS3D/SEAWAT) at its disposal to simulate variable-density groundwater flow and coupled solute transport. Deltares is engaged in the design of specific measures needed for salinisation prevention and adaptation and for saline aquifer management. We have a long professional track record on groundwater salinisation studies built up during numerous relevant projects worldwide.

    Leaflet (new)

    Fresh-saline groundwater in deltaic and coastal areas

    More Information

    Dr.ir. Gualbert Oude Essink
    T +31 (0)6 30550408
    gualbert dot oudeessink at deltares dot nl



    Project title
    fresh water supply
    climate change
    Knowledge for Climate
    Salinisation Zeeland
    Fresh-saline study Zuid-Holland
    Climate Proof Fresh Water Supply
    NHI fresh-salt
    GO-FRESH: Measures local freshwater supply
    FRESHEM ZEELAND / Airborne EM and numerical modelling
    Fresh-saline study Province of Flevoland
    Local salinisation phenomena
    Saline seepage in deltaic areas
    SWIBANGLA Managing saltwater intrusion impacts in Bangladesh
    Rise and Fall, Mekong
    Small Islands Developing States
    x x   x x x        


    PhD theses

    1. King, J., 2022. Airborne electromagnetic mapping of coastal groundwater salinity; Quantifying uncertainty and investigating methodological improvements, Utrecht University, Utrecht, 188 pp. 
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    2. Zamrsky, D., 2021. Current and future state of groundwater in coastal unconsolidated sediment systems worldwide, Utrecht University, Utrecht, 238 pp. 
      download PhD thesis
    3. Mabrouk, M.B., 2020. Climate Change and Development Impacts on Groundwater Resources in the Nile Delta Aquifer, Egypt. IHE Delft, 150 pp.

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    4. Van Engelen, J., 2020. Fresh groundwater reserves in major deltas: Evolution and current state of deltaic groundwater resources, Utrecht University, Utrecht, 194 pp. 
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    5. Aydin, B.E., 2020. Model Predictive Control of Water Level and Salinity in Coastal Areas. Delft University of Technology, 103 pp.

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    6. Huizer, S. 2019. Fresh groundwater in large beach nourishments; Growth of freshwater resources in coastal areas, Utrecht University, Utrecht, 152 pp. 
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    7. Delsman, J.R. 2015, Saline groundwater - surface water interaction in coastal lowlands, VU University Amsterdam, Amsterdam, 194 pp. 
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    8. Pauw, P.S. 2015. Field and Model Investigations of Freshwater Lenses in Coastal Aquifers, PhD thesis, Wageningen University, Wageningen, 168 pp.
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    9. De Louw, P.G.B. 2013. Saline seepage in deltaic areas. Preferential groundwater discharge through boils and interactions between thin rainwater lenses and upward saline seepage. PhD thesis, Vrije Universiteit Amsterdam, ISBN/EAN 9789461085429. 
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    • Van Engelen, J., Oude Essink, G.H.P., Bierkens, M.F.P., 2022. Sustainability of fresh groundwater resources in fifteen major deltas around the world. Environ. Res. Lett. 113650. https://doi.org/10.1088/1748-9326/aca16c download

    • Karaoulis, M., Ritsema, I., Bremmer, C., De Kleine, M., Oude Essink, G.H.P., Ahlrichs, E., 2022. Drone-Borne Electromagnetic (DR-EM) Surveying in The Netherlands: Lab and Field Validation Results. Water (Switzerland) 5335, 1–20. https://doi.org/https://doi.org/10.3390/rs14215335

    • Aydin, B.E., Oude Essink, G.H.P., Delsman, J.R., Van de Giesen, N., Abraham, E., 2022. Nonlinear model predictive control of salinity and water level in polder networks: Case study of Lissertocht catchment. Agric. Water Manag. 264, 11. https://doi.org/10.1016/j.agwat.2022.107502 download

    • Zamrsky, D., Oude Essink, G.H.P., Sutanudjaja, E.H., Van Beek, L.P.H., Bierkens, M.F.P., 2022. Offshore fresh groundwater in coastal unconsolidated sediment systems as a potential fresh water source in the 21st century. Environ. Res. Lett. 17. https://doi.org/10.1088/1748-9326/ac4073 download

    • King, J., Mulder, T., Oude Essink, G.H.P., Bierkens, M.F.P., 2022. Joint estimation of groundwater salinity and hydrogeological parameters using variable-density groundwater flow, salt transport modelling and airborne electromagnetic surveys. Adv. Water Resour. 160, 104118. https://doi.org/10.1016/j.advwatres.2021.104118 download

    • Thorslund, J., Bierkens, M.F.P., Oude Essink, G.H.P., Sutanudjaja, E.H., Van Vliet, M.T.H., 2021. Common irrigation drivers of freshwater salinisation in river basins worldwide. Nat. Commun. https://doi.org/10.1038/s41467-021-24281-8download
    • Gunnink, J., Pham, H. Van, Oude Essink, G.H.P., Bierkens, M.F.P., 2021. The 3D groundwater salinity distribution and fresh groundwater volumes in the Mekong Delta, Vietnam, inferred from geostatistical analyses. Earth Syst. Sci. Data 13, 3297–3319. https://doi.org/10.5194/essd-13-3297-2021download

    • Verkaik, J., Van Engelen, J., Huizer, S., Bierkens, M.F.P., Lin, H.X., Oude Essink, G.H.P., 2021. Distributed memory parallel computing of three-dimensional variable-density groundwater flow and salt transport. Adv. Water Resour. 154, 103976. https://doi.org/10.1016/j.advwatres.2021.103976download

    • Verkaik, J., Hughes, J.D., Van Walsum, P.E.V., Oude Essink, G.H.P., Lin, H.X., Bierkens, M.F.P., 2021. Distributed memory parallel groundwater modeling for the Netherlands Hydrological Instrument. Environ. Model. Softw. 143, 105092. https://doi.org/10.1016/j.envsoft.2021.105092 download

    • Willet, J., Wetser, K., Dykstra, J.E., Bianchi, A.B., Oude Essink, G.H.P., Rijnaarts, H.H.M., 2021. WaterROUTE: a model for cost optimization of industrial water supply networks when using water resources with varying salinity. Water Res. 117390. https://doi.org/10.1016/j.watres.2021.117390 download

    • Van Engelen, J., Bierkens, M.F.P., Delsman, J.R., Oude Essink, G.H.P., 2021. Factors determining the natural fresh-salt groundwater distribution in deltas. Water Resour. Res. https://doi.org/10.1029/2020WR027290 download
    • Karamouz, M., Mahmoodzadeh, D., Oude Essink, G.H.P., 2020. A risk-based groundwater modeling framework in coastal aquifers : a case study on Long Island , New York , USA. Hydrogeology Journal. https://doi.org/https://doi.org/10.1007/s10040-020-02197-9

    • Willet, J., King, J., Wetser, K., Dykstra, J.E., Oude Essink, G.H.P., Rijnaarts, H.H.M., 2020. Water supply network model for sustainable industrial resource use a case study of Zeeuws-Vlaanderen in the Netherlands. Water Resour. Ind. 24, 100131. https://doi.org/10.1016/j.wri.2020.100131

    • King, J., Oude Essink, G.H.P., Karaolis, M., Bierkens, M.F.P., 2020. A practical quantification of error sources in regional-scale airborne groundwater salinity mapping. Environ. Res. Lett. 1–18. https://iopscience.iop.org/article/10.1088/1748-9326/ab7b23, download

    • Zamrsky, D., Karssenberg, M.E., Cohen, K.M., Bierkens, M.F.P., Oude Essink, G.H.P., 2020. Geological heterogeneity of coastal unconsolidated groundwater systems worldwide and its influence on offshore fresh groundwater occurrence. Front. Earth Sci. 7, 1–23. https://doi.org/10.3389/feart.2019.00339

    • Haasnoot, M., Kwadijk, J.C.J., Van Alphen, J., Le Bars, D., Van den Hurk, B., Diermanse, F., Der Van Spek, A., Oude Essink, G.H.P., Delsman, J.R., Mens, M. 2019. Adaptation to uncertain sea-level rise; how uncertainty in Antarctic mass-loss impacts the coastal adaptation strategy of the Netherlands. Environ. Res. Lett. https://iopscience.iop.org/article/10.1088/1748-9326/ab666cdirect download
    • Van Engelen, J., Verkaik, J., King, J., Nofal, E. R., Bierkens, M. F. P., Oude Essink, G. H. P. 2019. A three-dimensional palaeohydrogeological reconstruction of the groundwater salinity distribution in the Nile Delta Aquifer, Hydrol. Earth Syst. Sci., 23, 5175–5198, https://doi.org/10.5194/hess-23-5175-2019.

    • Mabrouk, M., Jonoski, A., Oude Essink, G.H.P., Uhlenbrook, S., 2019. Assessing the fresh-saline groundwater distribution in the Nile Delta Aquifer using a 3D variable-density groundwater flow model. Water (Switzerland) 1–22., 11, 1946 doi:10.3390/w11091946 download

    • Huizer, S., Luijendijk, A.P., Bierkens, M.F.P., Oude Essink, G.H.P., 2019. Global potential for the growth of fresh groundwater resources with large beach nourishments. Sci. Rep. 1–14. https://doi.org/10.1038/s41598-019-48382-z download

    • Bakx, W., Doornenbal, P.J., Weesep, R.J., Bense, V.F., Oude Essink, G.H.P., Bierkens, M.F.P. 2019. Determining the Relation between Groundwater Flow Velocities and Measured Temperature Differences Using Active Heating-Distributed Temperature Sensing. Water, 11, 1619. https://doi.org/10.3390/w11081619 download
    • Aydin, B.E., Hagedooren, H., Rutten, M., Delsman, J., Oude Essink, G.H.P., Abraham, E., 2019. A Greedy Heuristic for Optimal Sensor Placement for Estimating Salinity in a Polder. Water (Switzerland) 11, 1–14. https://doi.org/10.3390/w11051101 download

    • Hung Van Pham, Van Geer, F.C., Bui Tran, V., Dubelaar, W.,Oude Essink, G.H.P. 2019. Paleo-hydrogeological reconstruction of the fresh-saline groundwater distribution in the Vietnamese Mekong Delta since the late Pleistocene. Journal of Hydrology: Regional Studies, 23(February), 100594. https://doi.org/10.1016/j.ejrh.2019.100594download

    • Mabrouk, M., Jonoski, A., Oude Essink, G.H.P., Uhlenbrook, S., 2018. Impacts of Sea Level Rise and Groundwater Extraction Scenarios on Fresh Groundwater Resources in the Nile Delta Governorates, Egypt. Water 10, 1690. doi:10.3390/w10111690 download
    • Aydin, B.E., Tian, X., Delsman, J., Oude Essink, G.H.P., Rutten, M., Abraham, E., 2019. Optimal Salinity and Water Level Control of Polder Ditches using Model Predictive Control. Environ. Model. Softw. doi:10.1016/j.envsoft.2018.11.010 download
    • Post, V. E. A., Galvis, S. C., Sinclair, P. J. and Werner, A. D. 2019. Evaluation of management scenarios for potable water supply using script- based numerical groundwater models of a freshwater lens, J. Hydrol., 571, 843–855, doi:10.1016/j.jhydrol.2019.02.024. download
    • King, J., Oude Essink, G.H.P., Karaolis, M., Siemon, B., Bierkens, M.F.P., 2018. Quantifying inversion algorithms using airborne frequency domain electromagnetic data – applied at the Province of Zeeland, the Netherlands. Water Resour. Res. 2060, 1–22. doi:10.1029/2018WR023165 download
    • Zamrsky, D., Oude Essink, G.H.P., Bierkens, M.F.P.: 2018. Estimating the thickness of unconsolidated coastal aquifers along the global coastline, Earth Syst. Sci. Data, 10, 1591-1603, https://doi.org/10.5194/essd-10-1591-2018 download
    • Delsman, J., Van Baaren, E.S., Siemon, B., Dabekaussen, W., Karaoulis, M.C., Pauw, P., Vermaas, T., Bootsma, H., De Louw, P.G.B., Gunnink, J.L., Dubelaar, W., Menkovic, A., Steuer, A., Meyer, U., Revil, A., Oude Essink, G.H.P., 2018. Large-scale, probabilistic salinity mapping using airborne electromagnetics for groundwater management in Zeeland, the Netherlands. Environ. Res. Lett. 13. doi:10.1088/1748-9326/aad19edownload
    • Post, V.E.A., Oude Essink, G.H.P., Szymkiewicz, A., Bakker, M., Houben, G., Custodio, E., Voss, C., 2018, Celebrating 50 years of SWIMs (Salt Water Intrusion Meetings). Hydrogeology, 26:1767–1770. https://doi-org.proxy.library.uu.nl/10.1007/s10040-018-1800-8 download
    • Van Engelen, J., Oude Essink, G. H. P., Kooi, H., and Bierkens, M. F. P. 2018. On the origins of hypersaline groundwater in the Nile Delta aquifer. Journal of Hydrology, 560, 301-317. https://doi.org/10.1016/j.jhydrol.2018.03.029 download
    • Huizer, S., Radermacher, M., de Vries, S., Oude Essink, G. H. P., and Bierkens, M. F. P. 2018. Impact of coastal forcing and groundwater recharge on the growth of a fresh groundwater lens in a mega-scale beach nourishment, Hydrol. Earth Syst. Sci., 22, 1065-1080, https://doi.org/10.5194/hess-22-1065-2018.
    • Post, V.E.A., Bosserelle, A.L., Galvis, S.C., Sinclair, P.J., Werner, A.D., 2018. On the resilience of small-island freshwater lenses: Evidence of the long-term impacts of groundwater abstraction on Bonriki Island, Kiribati. J. Hydrol. 564, 133–148. doi:10.1016/j.jhydrol.2018.06.015 download
    • Werner, A.D., Sharp, H.K., Galvis, S.C., Post, V.E.A., Sinclair, P., 2017. Hydrogeology and management of freshwater lenses on atoll islands: Review of current knowledge and research needs. J. Hydrol. 551, 819–844. doi:10.1016/j.jhydrol.2017.02.047 download 
    • Huizer, S., Karaoulis, M.C., Oude Essink, G.H.P., Bierkens, M.F.P., 2017, Monitoring and simulation of salinity changes in response to tide and storm surges in a sandy coastal aquifer system, Water Resources Research, doi: 10.1002/2016WR020339download
    • Revil, A., Coperey, A., Shao, Z., Florsch, N., Fabricius, I.L.L., Deng, Y., Delsman, J.R., Pauw, P.S., Karaoulis, M., De Louw, P.G.B., Van Baaren, E.S., Dabekaussen, W., Menkovic, A., Gunnink, J.L. 2017. Complex conductivity of soils. Water Resources Research, 53(8), 7121–7147. https://doi.org/10.1002/2017WR020655download
    • Delsman, J.R., De Louw, P.G.B., De Lange, W.J., Oude Essink, G.H.P., 2017, Fast calculation of groundwater exfiltration salinity in a lowland catchment using a lumped celerity / velocity approach, Environmental Modelling and Software, 96, 323–334, doi: 10.1016/j.envsoft.2017.07.004download
    • Eeman, S., De Louw, P.G.B., van der Zee, S.E.A.T.M., 2017. Cation exchange in a temporally fluctuating thin freshwater lens on top of saline groundwater. Hydrogeol. J. 25, 223–241. doi:10.1007/s10040-016-1475-y.  download

    • Huizer, S., Oude Essink, G.H.P., Bierkens, M.F.P., 2016, Fresh groundwater resources in a large sand replenishment, Hydrol. Earth Syst. Sci., 20, 3149-3166, doi:10.5194/hess-20-3149-2016download
    • Stofberg, S.F., Oude Essink, G.H.P., Pauw, P., De Louw, P.G.B., Leijnse, A., van der Zee, S.E.A.T.M., 2016, Fresh Water Lens Persistence and Root Zone Salinization Hazard Under Temperate Climate, Water Resources Management, doi: 10.1007/s11269-016-1315-9download 
    • Delsman, J. R., Winters, P., Vandenbohede, A., Oude Essink, G. H.P. and Lebbe, L., 2016, Global sampling to assess the value of diverse observations in conditioning a real-world groundwater flow and transport model. Water Resour. Res. doi:10.1002/2014WR016476.download
    • Pauw P.S., van der Zee S.E.A.T.M., Leijnse A., Oude Essink G.H.P., 2015, Saltwater Upconing Due to Cyclic Pumping by Horizontal Wells in Freshwater Lenses.  Ground Water, Vol 54 (4), 521-531. doi: 10.1111/gwat.12382download 
    • Pauw, P.S., Van Baaren, E.S., Visser, M. De Louw, P.G.B., Oude Essink, G.H.P., 2015, Increasing a freshwater lens below a creek ridge using a controlled artificial recharge and drainage system: a case study in the Netherlands, Hydrogeology Journal. doi: 10.1007/s10040-015-1264-zdownload
    • De Louw, P.G.B., Oude Essink, G.H.P., Eeman, S., Van Baaren, E.S., Vermue, E., Delsman, J.R., Pauw, P.S., Siemon, B., Gunnink, J.L., Post, V.E.A., 2015, Dunne regenwaterlenzen in zoute kwelgebieden, Landschap, 32, 5-15.download
    • Zeghici, R.M., Oude Essink, G.H.P., Hartog, N., Sommer, W., 2015, Integrated assessment of variable density–viscosity groundwater flow for a high temperature mono-well aquifer thermal energy storage (HT-ATES) system in a geothermal reservoir. Geothermics, 55, 58–68. doi: 10.1016/j.geothermics.2014.12.006download
    • Pauw, P.S., van der Zee, S.E.A.T.M., Leijnse, A., Delsman, J.R., De Louw, P.G.B., de Lange, W.J., Oude Essink, G.H.P. 2015. Low-Resolution Modeling of Dense Drainage Networks in Confining Layers, Ground water, 1-11, doi: 10.1111/gwat.12273
    • Delsman, J.R., Waterloo, M.J., Groen, M.M.A. Groen, J., Stuyfzand, P.J. 2014 Investigating summer flow paths in a Dutch agricultural field using high frequency direct measurements, J. Hydrology, doi: 10.1016/j.jhydrol.2014.10.058
    • De Lange, W.J., Prinsen, G.F., Hoogewoud, J.C., Veldhuizen, A., Verkaik, J., Oude Essink, G.H.P., van Walsum, P.E.V., Delsman, J.R., Hunink, J.C., Massop, H.T.L., Kroon, T., 2014. An operational, multi-scale, multi-model system for consensus-based, integrated water management and policy analysis: The Netherlands Hydrological Instrument. Environmental Modelling & Software 59, 98–108, doi: 10.1016/j.envsoft.2014.05.009download
    • Pauw, P.S., Oude Essink, G.H.P., Leijnse, A., Vandenbohede, A., Groen, J., van der Zee, S.E.A.T.M. 2014. Regional scale impact of tidal forcing on groundwater flow in unconfined coastal aquifers, J. Hydrology, 517, 269–283, doi: 10.1016/j.jhydrol.2014.05.042 .download
    • Delsman, J.R., Hu-a-ng, K.R.M., Vos, P.C., de Louw, P.G.B., Oude Essink, G.H.P., Stuyfzand, P.J., & Bierkens, M.F.P. 2014. Paleo-modeling of coastal saltwater intrusion during the Holocene: an application to the Netherlands.  Hydrology and Earth System Sciences18(10), 3891–3905, doi: 10.5194/hess-18-3891-2014link to paperlink to animation
    • Vandenbohede, A., de Louw, P.G.B., Doornenbal, P.J.P.J., 2014. Characterizing preferential groundwater discharge through boils using temperature. Journal of Hydrology 510, 372–384, doi: 10.1016/j.jhydrol.2014.01.006
    • De Louw, P.G.B., Eeman, S., Oude Essink, G.H.P., Vermue, E., Post, V.E.A. 2013. Rainwater lens dynamics and mixing between infiltrating rainwater and upward saline groundwater seepage beneath a tile-drained agricultural field. J. Hydrology, 501, 133-145, doi: 10.1016/j.jhydrol.2013.07.026link to paper
    • Delsman, J.R., Oude Essink, G.H.P., Beven, K.J., Stuyfzand, P.J. 2013. Uncertainty estimation of end-member mixing using generalized likelihood uncertainty estimation (GLUE), applied in a lowland catchment, Water Resour. Res. 49 4792 4806, doi:   10.1002/wrcr.20341download
    • De Louw, P.G.B., Vandenbohede, A., Werner, A.D., Oude Essink, G.H.P. 2013. Natural saltwater upconing by preferential groundwater discharge through boils. J. Hydrol., 490, 74-87, doi: 10.1016/j.jhydrol.2013.03.025download
    • Faneca Sànchez , M., Gunnink , J.L., van Baaren , E.S., Oude Essink G.H.P., Siemon, B. , Auken, E. , Elderhorst, W. , de Louw, P.G.B.  2012. Modelling climate change effects on a Dutch coastal groundwater system using airborne Electro Magnetic measurements, Hydrol. Earth Syst. Sci., 16, 4499-4516, doi: 10.5194/hess-16-4499-2012download
    • Pauw, P.S., Louw, P.G.B., de, Oude Essink, G.H.P. 2012. Groundwater salinization in the Wadden Sea area of the Netherlands; quantifying the effects of climate change, sea level rise and anthropogenic interferences, Netherlands Journal of Geosciences 91-3, 373-383, doi: 10.1017/S0016774600000500link to NJG
    • Harbo, M.S., Pedersen, J. Johnsen., R. and Petersen, K. 2012. (Eds) The CLIWAT handbook: Groundwater in a future climate, www.cliwat.eu. 184 p. CLIWAT Handbook
    • Oude Essink, G.H.P. and Kooi, H. 2012. Land-subsidence and sea-level rise threaten fresh water resources in the coastal groundwater system of the Rijnland water board, The Netherlands, p. 227-248, Chapter 13 in: Climate Change Effects on Groundwater Resources: A Global Synthesis of Findings and Recommendations, Treidel, H., Martin-Bordes, J.L. and Gurdak, J.J. (Eds), 401 p. link to Book
    • Louw, P.G.B., de, Eeman, S., Siemon, B., Voortman, B.R., Gunnink, J., van Baaren, E.S., and Oude Essink, G.H.P., 2011, Shallow rainwater lenses in deltaic areas with saline seepage, Hydrol. Earth Syst. Sci., 15, 3659-3678, doi: 10.5194/hess-15-3659-2011link to HESS
    • Louw, P.G.B., de, van der Velde, Y., and van der Zee, S.E.A.T.M. 2011. Quantifying water and salt fluxes in a lowland polder catchment dominated by boil seepage: a probabilistic end-member mixing approach, Hydrol. Earth Syst. Sci., 15, 2101-2117, doi: 10.5194/hess-15-2101-2011ink to HESS
    • Louw, P.G.B., de, Oude Essink, G.H.P., Stuyfzand, P.J., Zee, van der, S.E.A.T.M. 2010. Upward groundwater flow in boils as the dominant mechanism of salinization in deep polders, The Netherlands, J. Hydrol. 394, 494-506, doi: 10.1016/j.jhydrol.2010.10.009download
    • Oude Essink, G.H.P., E.S. van Baaren, and P.G.B. de Louw. 2010. Effects of climate change on coastal groundwater systems: A modeling study in the Netherlands, Water Resour. Res., 46, W00F04, doi: 10.1029/2009WR008719download
    • Goes, B.J.M., Oude Essink, G.H.P., Vernes, R.W. and Sergi, F. 2009. Estimating the depth of fresh and brackish groundwater in a predominantly saline region using geophysical and hydrological methods, Zeeland, the Netherlands, Near Surface Geophysics 401-412, doi: 10.3997/1873-0604.2009048download
    • Giambastiani, B.M.S., Antonellini, M., Oude Essink, G.H.P. and Stuurman, R.J. 2007. Saltwater intrusion and water management in the unconfined coastal aquifer of Ravenna (Italy): a numerical model, J. of Hydrol. (340), 1-2, 91-104, doi: 10.1016/j.jhydrol.2007.04.001download
    • De Louw, P. and Oude Essink, G.H.P. 2006. Salinisation of the Northern coastal area of the Netherlands due to land subsidence and sea level rise. In: Jun Xu, Y. and Singh, V.P. (Eds.): Coastal Environmental and Water Quality, AIH Annual Meeting & International Conference, Challenges in Coastal Hydrology and Water Quality, Baton Rouge, Louisiana, 167-179. download
    • Langevin, C.D., G.H.P. Oude Essink, Panday, S., Bakker, M., Prommer, H., Swain, E.D., Jones, W., Beach, M. and Barcelo, M. 2003. MODFLOW-Based Tools for Simulation of Variable-Density Groundwater Flow. In: Coastal Aquifer Management-Monitoring, Modeling and Case Studies. A.H.-D. Cheng and D. Ouazar, CRC Press, 30-76. download draft
    • Bakker, M., Oude Essink, G.H.P. and Langevin, C.D. 2004. The rotating movement of three immiscible fluids, J. of Hydrol. (287), 270-278, doi: 10.1016/j.jhydrol.2003.10.007download
    • Bouw, L. and Oude Essink, G.H.P. 2003. Development of a freshwater lens in the inverted Broad Fourteens Basin, Netherlands offshore, J. of Geochemical Exploration 78-79: 321-325, doi: 10.1016/S0375-6742(03)00113-4download
    • Bouw, L. and Oude Essink, G.H.P. 2003. Fluid flow during Late Cretaceous inversion of the northern Broad Fourteens Basin, Netherlands J. of Geosciences 82 (1): 55-69. download
    • Oude Essink, G.H.P. 2001. Salt Water Intrusion in a Three-dimensional Groundwater System in The Netherlands: a Numerical Study, Transport in Porous Media 43(1): 137-158, doi:  10.1023/A:1010625913251download
    • Oude Essink, G.H.P. 2001. Improving fresh groundwater supply - problems and solutions. Ocean & Coastal Management 44: 429-449, doi: 10.1016/S0964-5691(01)00057-6 . download
    • Oude Essink, G.H.P. 2001. Saltwater intrusion in 3D large-scale aquifers: a Dutch case, Phys. & Chem. of the Earth 26(4): 337-344, doi: 10.1016/S1464-1909(01)00016-8download
    • Oude Essink, G.H.P. 2001. Density dependent groundwater flow at the island of Texel, The Netherlands. Proc. 16th Salt Water Intrusion Meeting, Miedzyzdroje-Wolin Island, Poland: 47-54. download
    • Klein, R.J.T., R.J. Nicholls, G.H.P. Oude Essink, N. Minura and R.A. Warrick. 1998. Coastal Zones (Chapter 7). Unites Nations Environmental Programme, in UNEP Handbook on Methods for Climate Change Impact Assessments and Adaptation Strategies,. J.F. Feenstra, I. Burton, J.B. Smith and R.S.J. Tol (Eds), CRC Press, 464 p. download
    • Oude Essink, G.H.P. 1998. MOC3D adapted to simulate 3D density-dependent groundwater flow. In: Proc.MODFLOW'98 Conference, October 4-8, 1998, Golden, Colorado, USA, Vol. I, 291-303. download
    • Oude Essink, G.H.P. 1996. Impact of sea level rise on groundwater flow regimes. A sensitivity analysis for the Netherlands. Ph.D. thesis, Delft University of Technology. Delft Studies in Integrated Water Management: no. 7 ISBN 90-407-1330-8. 428 p. download
    • Oude Essink, G.H.P. Boekelman, R.H., 1996. Problems with large-scale modelling of salt water intrusion in 3D, Proc. 14th Salt Water Intrusion Meeting, Malmo, Sweden. download
    • Jelgersma, S., M. J. Tooley, G.H.P. Oude Essink, R.H. Boekelman, M.C.J. Bosters, W.J. Wolff, K.S. Dijksma, B.J. Ens, L. Bijlsma, R. Hillen, and R. Misdorp. 1993. Sea Level Changes and their Consequences for Hydrology and Water Management, State of the Art Report, UNESCO, IHP-IV Project H-2-2, 135 p. 

    Reports (in English)

    Oude Essink, G.H.P., Van der Linden, W. 2005, Impact of the 26-12-04 Tsunami on groundwater systems and groundwater based water supplies, TNO report 2006-U-R-172/A, 19 p., Utrecht, The Netherlands. download

    Abstracts and Posters

    1. Autonomic and climatic impacts on the Dutch coastal groundwater system, AGU 2008
      Authors: Esther van Baaren and Gualbert Oude Essink Poster Abstract
    2. CLIWAT: a transnational project about climate change and coastal groundwater in the North Sea Region, SWIM 21 2010
      Authors: Gualbert Oude Essink, Perry De Louw, and many others! Poster Abstract
    3. Salinisation and freshening of phreatic groundwaters in Zeeland, The Netherlands: a modeling study, SWIM 21 2010
      Authors: Esther van Baaren, Perry de Louw, Gualbert Oude Essink Poster Abstract
    4. Netherlands Hydrological modelling Instrument for fresh and saline groundwater in the Dutch coastal zone, SWIM 21 2010
      Authors: Jarno Verkaik, Esther van Baaren, Joost Delsman and Gualbert Oude Essink Poster Abstract
    5. Analysis of Submarine Groundwater Discharge to Manila Bay: Density Dependent Hydrogeological Modeling of the South-eastern coastal zone of Bataan, Philippines, SWIM 21 2010
      Authors: Aileen Mirasol-Robert, Gualbert Oude Essink, Hans H. Dürr Abstract
    6. Uncertainty in end-member mixing: a blessing in disguise?, EGU 2012
      Authors: Joost Delmans, Gualbert Oude Essink Poster


    Course Hazards and risk assessment GEO4-4425, Utrecht University, 20 March 2020

    Topic: Vulnerability of groundwater systems to flooding events

    Download:   Powerpoint presentation: pdf format  
    Download:   Effect saline flooding event on groundwater: pdf document  
    Download:   saltfresh_flooding: PMWIN files, Exercise 1
    Download:   saltfresh_flooding: PMWIN files, Exercise 5

    Lecture Notes Density Dependent Groundwater Flow: Salt water intrusion in coastal aquifers

    Auteur: Gualbert Oude Essink 
    Dictaat: Density Dependent Groundwater Flow

    1 Introduction
    2 Characteristics of a density dependen groundwater system
    3 Freshwater head
    4 The concept of a fresh-saline interface
    5 Control of salt water intrusion
    6 Numerical modelling
    7 Salt water intrusion in the Netherlands
    8 Heat transport in porous media: introduction

    Lecture Notes Groundwater Modelling

    Auteur: Gualbert Oude Essink 
    Dictaat: Groundwater Modelling 
    PART I Modelling Protocol 
    1 Introduction 
    2 Classification of mathematical models 
    3 Methodology of modelling 
    4 Data gathering 
    PART II Groundwater Modelling 
    5 Introduction 
    6 Mathematical description of hydrogeologic processes 
    7 Solution techniques 
    8 Numerical aspects of groundwater models 
    9 Some selected groundwater codes

    Animations: examples of salinisation processes

    Henry's profile with sea level rise
    3D zoet-zout verdeling ondergrond NL
    Fresh water injection to combat salinisation
    3D zoet-zout verdeling ondergrond Texel
    Regional groundwater flow, partly captured by a sandy boil  

    Henry's profile with sea level rise
    3D zoet-zout verdeling ondergrond NL
    Fresh water injection to combat  salinisation
    3D zoet-zout verdeling ondergrond Texel
    Regional groundwater flow, partly captured by a sandy boil
    Physical barrier in the coastal zone
    Dutch profile: extraction, upconing and low inland levels
    Profile over 3D model: effect sea level rise on salinisation
    Movement of the island De Griend (NL): creation of a freshwater lens
    Evolution of a freshwater lens
    Physical barrier in the coastal zone
    Dutch profile extraction, upconing and low inland levels
    Profile over 3D model: effect sea level rise on salinisation
    Movement of the island De Griend (NL): creation of a freshwater lens
    Evolution of a freshwater lens


    Homepage Salt Water Intrusion Meetings



    • 25th Salt Water Intrusion Meeting in Gdansk, 17-22 June, 2018

      • Delsman, J.R., Van Baaren, E.S., Siemon, B., Dabekaussen, W., Steuer, A., Gunnink, J.L., Karaoulis, M.C., Pauw, P.S., Vermaas, T., Bootsma, H., De Louw, P.G.B., Oude Essink, G.H.P. 2018. Large-scale, probabilistic airborne salinity mapping for groundwater management in Zeeland, The Netherlands
      • De Louw, P.G.B., Bootsma, H., Kooi, H., Kramer, M., Erkens, G. 2018. Land subsidence by peat oxidation leads to enhanced salinization through boils in Dutch polders
      • Zamrsky, D., Oude Essink, G.H.P., Bierkens, M.F.P. 2018. Estimating characteristic times of regional groundwater systems along the global coastline with regard to past sea level fluctuations and sediment accumulation patterns
      • Van Engelen, J., Bierkens, M.F.P., Oude Essink, G.H.P. 2018. 3D Paleohydrogeological modelling of the Nile Delta
      • King, J., Oude Essink, G.H.P., Karaoulis, M.C., Siemon, B., Bierkens, M.F.P. 2018. A Quantitative Review of D Airborne Electromagnetic Inversion Methods: A Focus on Fresh-Saline Groundwater Mapping
      • Huizer, S., Radermacher, M., De Vries, S., Oude Essink, G.H.P., Bierkens, M.F.P. 2018. Impact of coastal forcing and groundwater recharge on the growth of a fresh groundwater lens in a mega-scale beach nourishment
      • Oude Essink, G.H.P., Mulder, T., Van Engelen, J., Zamrsky, D., Pham Van, H., Weerasekera, W., Meggiorin, M. 2018. Building up D salinity models for estimating fresh groundwater resources in major deltas under global and climate stresses
      • Vandevelde, D. Van Baaren, E.S., Delsman, J.R., Karaoulis, M.C., Oude Essink, G.H.P. De Louw, P.G.B., Vermaas, T., Pauw, P.S., De Kleine, M., Thofte, S., Teilmann, R., Walraevens, K., Van Camp, M., Huits, D., Dabekaussen, W., Gunnink, J.L., Vandenbohede, A. 2018. Groundwater salinity mapping of the Belgian coastal zone to improve local freshwater storage availability
      • Oude Essink, G.H.P., Van Baaren, E.S., Galvis Rodriguez, S., Zuurbier, K., Raat, K., Kooiman, J.W., Boonekamp, T. 2018. Potential map for large-scale implementation of subsurface water solutions: COASTAR
      • Verkaik, J., Huizer, S., Van Engelen, J., Ram, R., Vuik, K., Oude Essink, G.H.P. 2018. Parallel Computing with SEAWAT
      • America, I., De Louw, P.G.B., Bier, G., Van der Zee, S. 2018. Influence of tides, bathymetry, lithology and regional flows on the salinization process in nature area the Rammegors


    • 2017 23-28 April: European Geosciences Union, General Assembly
      • Zamrsky, D., Bierkens, M. and G.H.P. Oude Essink, 2017. On aquifer thicknesses and geological complexity affecting fresh/salt groundwater distribution.

      • Van Engelen, J., Oude Essink, G.H.P., Kooi, H., Bierkens, M.F.P. 2017. On the origins of hypersaline groundwater in the Nile Delta Aquifer.

      • Boran, B.E., Rutten, M., Oude Essink, G.H.P., Delsman, J.R., Abraham, E. 2017 Smart salinity management in low-lying deltaic areas: a model predictive control scheme applied to a test case.

      • Siemon, B., Van Baaren, E., Dabekaussen, W., Delsman, J.R., Gunnink, J., Karaoulis, M., De Louw, P., Oude Essink, G., Pauw, P., Steuer, A., Vermaas, T., Meyer, U. 2017. FRESHEM - Fresh-saline groundwater distribution in Zeeland (NL) derived from airborne EM.

    • Wanted: Ghent University Belgium: Assistant Prof. Hydrogeology







    World Delta Summit, The Pulse of Deltas and the Fate of our Civilization, Jakareta Indonesia, 21-24 November 2011


    International Centre for Advanced Mediterranean Agronomic Studies CIHEAM course, 22-27 March 2010, Zaragoza, Spain, teaching Quantitative methods

    21st Salt Water Intrusion Meeting 21-25 June 2010, Azores, Portugal

    Deltas in Times of Climate Change 29 September- 1 October, Rotterdam, the Netherlands
    Presentation: Oude Essink GHP, Van Baaren ES, De Louw PGB, 2010, Effects climate change on coastal groundwater systems, focus on the Rhine Delta, Proceedings Deltas in Times of Climate Change, Rotterdam, The Netherlands, Sept-Oct. 2010


    Blog stream

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    Students already contribute a number of years to our projects on fresh and salt groundwater in the coastal area. Sometimes with nice reports, sometimes with great results, article worthy! As such, this made that we are a strong supporter of guiding students through internships or thesis (both MSc and PhD)! We have already had students from Dutch universities (WUR, UU, VU), Universities of Applied Sciences (Zeeland, Larensteijn) and institutions like UNESCO-IHE. Foreign (PhD) students were welcome (Universities of Aachen, Ghent, Firenze, Bologna, Roma (La Sapienza). Tehran).

    We have quite a few new topics, from numerical modeling to water system analysis using monitoring techniques. Just contact us, or the students below via e.g. LinkedIn!


    New topics:

    1. Groundwater salinization near the IJmuiden Sea Lock

    2. Simulating the effect of different scenarios on climate change/sea-level rise and anthropogenic stresses on fresh groundwater in the Mekong delta, using the existing 3D model 
    3. On the water - food nexus in the Nile delta: communicating, understanding and monitoring groundwater availability, collaboration with the universities Kafr El Sheikh and Sadat City; also a visit to Egypt is planned.
    4. Comparison of 2D and 3D groundwater flow and salinity model estimations in deltaic regions
    5. Assessing the economic and technic feasibility of offshore groundwater pumping, based on the article Zamrsky, D., Oude Essink, G.H.P., Sutanudjaja, E.H., Van Beek, L.P.H., Bierkens, M.F.P., 2022. Offshore fresh groundwater in coastal unconsolidated sediment systems as a potential fresh water source in the 21st century. Environ. Res. Lett. 17, 1–22. https://doi.org/https://doi.org/10.1088/1748-9326/ac4073
    6. Assessing the effect of model parameters (e.g. solute solvers, grid convergence) on variable-density groundwater and salt transport benchmark cases using iMOD-SEAWAT and/or MODFLOW6
    7. Fresh groundwater resources management at a farmers level in the province of Zeeland, The Netherlands: setting up robust web-based clipping tools; a modelling study
    8. Assessing submarine groundwater discharge along coastal stretches: a global analysis
    9. Setting up a 3D variable-density groundwater flow model simulating salt water intrusion in a deltaic area: possible cases: the Bengal, Indus, Po, Yangtze, Pearl river deltas

    info: gualbert dot oudeessink at deltares dot nl

    Examples past studies since 2005:






    Wayangi Lakshani Weerasekera, IHE-Delft, 3D Variable-density Groundwater Modelling of the Red River Delta, Vietnam








    • Tommaso Letterio, Uni of Firenze, Italy


    • Bas de Veen en Sjors Stevens, VU Amsterdam, Monitoring campaign rainwater lenses in the province of Zeeland (in Dutch)
    • Corne Prevo, HZ University of Applied Sciences, Aquatische Ecotechnologie: Rainwater lenses in the province of Zeeland (in Dutch)
    • Francesco Sergi, La Sapienza, Roma, Italy, Salinisation processes in the Province of Zeeland, the Netherlands, contribution to Near Surface Geophysics, 401-412, 2007
    • Marian Koskamp, Wageningen UR, Model study of chloride concentration in soil moisture and shallow groundwater in a saline seepage system (in Dutch)
    • Valentina Marconi, Uni of Bologna, Italy, Characterization of shallow fresh groundwater lenses in the Province of Zeeland with 2D geo-electrical surveys
    • Vesna Tripkovics, UNESCO-IHE, Salt water intrusion in The Province of Zeeland, the Netherlands - water system analysis and numerical modeling



    • Beatrice Giambastiani, Uni of Bolgona, Italy, Saltwater intrusion and water management in the unconfined coastal aquifer of Ravenna (Italy): a numerical model J. Hydrol. 340, 1-2, 91-104, 2007


    Course Groundwater in the coastal zone

    18-20 September 2014, Delft – The Netherlands

    download flyer for detailed information

    | | !


    The course will provide participants with (1) principles and procedures of variable density groundwater flow and coupled solute transport, (2) salinisation of groundwater systems and fresh-saline groundwater flow phenomena in the coastal zone, (3) monitoring techniques for fresh-brackish-saline water systems and (4) modelling experiences through hands-on training in computer workshops. On completion of this course the participants are able to understand, quantify and monitor groundwater flow processes in the coastal zone and to construct some (relatively simple) models on variable density groundwater flow and coupled salt transport. A fi eld visit to the south-western part of the Netherlands will provide participants some field experiences in handling monitoring techniques to understand fresh-saline groundwater systems.


    The following persons participate in the fresh-salt research on this wiki:

    Gu Oude Essink
    Perry de Louw
    Esther van Baaren
    Marta Faneca Sanchez
    Jarno Verkaik
    Joost Delsman
     Gijs Janssen
    Tobias Mulder
    Martijn Visser
    Pieter Pauw
    Gualbert dot OudeEssink at Deltares dot nl
    Perry dot deLouw at Deltares dot nl
    Esther dot vanBaaren at Deltares dot nl
    Marta dot Faneca at Deltares dot nl
    Jarno dot Verkaik at Deltares dot nl
    Joost dot Delsman at Deltares dot nl
    Gijs dot Janssen at Deltares dot nl
    Tobias dot Mulder
    at Deltares dot nl
    Martijn dot Visser at Deltares dot nl
    Pieter dot Pauw at Deltares dot nl



    G-EMMA is software written to facilitate end-member mixing analysis within a GLUE uncertainty assessment framework. 

    G-EMMA has its own website: http://g-emma.deltares.nl/

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