Critical Zone Hydrology Group





L.A. Bruijnzeel

P.J. Stuyfzand

H. Kooi

M.J. Waterloo

B.M. van Breukelen

H.J. van Meerveld

J. Groen

M.M.A. Groen

H.P. Broers

J. Schellekens

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Perry de Louw

Position: PhD student
Telephone: +31 6 30548000

Position: Researcher
Dept. of Soil and Groundwater
P.O. Box 85467
3508 AL Utrecht
The Netherlands

Saline seepage

Supervisors and collaborators:

Duration: 5 years
Funding: Deltares Research Program

Research questions

In many deltaic areas, the groundwater is saline because of seawater intrusion and marine transgressions. In areas that lie below mean sea level saline groundwater may reach the surface by upward groundwater flow, which we define here as seepage. This leads to salinization of surface waters and shallow fresh groundwater bodies and makes the water unfit for irrigation, drinking water supply or industrial purposes. A future rise in sea level and climate change is expected to increase the seepage and salt loads to surface waters and reduce the availability of both fresh surface water and groundwater. Study area is the Netherlands. The objective of my PhD is to describe and quantify the main and most important processes / mechanisms of saline seepage in time and space. Looking at the fresh water availability of the Dutch delta, two important saline seepage related phenomena are observed and subject of research:

These two phenomena act in different regions which different characteristics (geohydrology, salinity, etc.). Preferential saline seepage occurs mainly in the deep polders with large hydraulic gradients, which are characterized by a moderate deep fresh-brackish interface (20 to 50 m). The objective is to describe and quantify the salinization processes by preferential seepage via boils. Rainwater lenses are important in areas with saline groundwater at shallow depth like the southwestern Dutch delta, i.e. 50 to 100% seawater is found at 1 to 5 meter depths. The objective is to characterize and quantify the mixing and dynamic behavior of these small lenses on top of saline seeping groundwater.