Global Hydrology

New publication

A new global groundwater model and the impacts of sea-level rise on coastal fresh groundwater

We have two new exciting publications to show.

Paper 1:GLOBGM v1.0: a parallel implementation of a 30 arcsec PCR-GLOBWB-MODFLOW global-scale groundwater model

Jarno Verkaik‘s next paper is out! He presents the first 1 km transient two-layer global groundwater model. Another step towards better representation of groundwater in Earth System Models and improving global groundwater sustainability assessment.
Co-authors: Gualbert Oude Essink
Edwin Sutanudjaja Hai Xiang Lin Marc BierkensSee the paper at: few words about the technology that Jarno applied:
The underlying model code (MODFLOW 6) is changed in such a way that it runs efficiently in parallel on multiple processors of a computer cluster. Unstructured grids are used to minimize the number of computational cells and associated runtime and storage. Also, parallel data processing is applied, which is required to handle the many terabytes of input and output data. This way one is able to run 60 years over night with as little computational resources as possible and makes the use of this model feasible for users that do not have access to very large computers.The development of this model combines the strength of Deltares in developing modelling tools with Utrecht University‘s global modelling expertise and global data sets.

This work is also part of the European Research Council (ERC) hashtagGEOWAT project.

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Paper 2:Global Impact of Sea Level Rise on Coastal Fresh Groundwater Resources
A new paper by Daniel Zamrsky.
Sea levels are projected to rise by more than 0.7m by year 2100 and reaching more than 3.3m rise by year 2300. Apart from its obvious and devastating impacts above ground level, what is the future of groundwater resources in coastal regions worldwide? Are we facing a hidden threat to our fresh groundwater in the coming centuries due to sea level rise?
Together with Marc Bierkens and Gualbert Oude Essink we studied the effects of sea level rise on fresh coastal groundwater resources worldwide. The projections in our newest paper indicate that, under severe sea level rise scenarios, more than 60 million individuals may lose over 5% of their freshwater resources by 2100, escalating to 120 million by 2300.
To protect coastal communities against this threat, water management and collaborations between fields working on environmental issues will be essential. If you would like to talk about our research or collaborate, please send a message!
For more details please don’t hesitate to dive into the full study at or read the press release at
Details are in the caption following the image

Difference in inland fresh groundwater volume (IFGV) in year 2100 expressed as percentage IFGV compared to situation in year 2000. Results are averaged over the three different digital elevation model inputs used in our modeling study for each Representative Concentration Pathway (RCP) scenario—(a) RCP 2.5, (b) RCP 4.5 and (c) RCP 8.5.