EngD position on The flushing of trapped saltwater from bathymetric depressions in a semi-closed estuary by freshwater river discharge.

The Haringvliet Estuary in the western part of the Netherlands was closed off in 1970 by a series of locks as part of the Delta Works for coastal protection. After the closure, the Haringliet became a freshwater body and was used as a source of freshwater for consumption and agriculture. Since 2018, the operating policy of the Haringvliet locks has changed and some locks are opened not only to discharge the river to the sea but also to allow limited inflows from the sea during flood tides to enhance the ecosystem functions of the estuary. The incoming saltwater should ideally be flushed out during the subsequent ebb tide. However, the Haringvliet Estuary has several bathymetric depressions that can store large amounts of saltwater, which, depending on the flow conditions, may not mix easily with the freshwater pulses due to the density differences. In such cases, the freshwater flows over the saltwater for extended periods of low river discharge and the flushing of the saltwater from the scour holes may occur in undesirable periods (e.g., due to wind-driven flow recirculation when the locks are closed), affecting the freshwater intakes.

This EngD project will investigate the mixing processes between saltwater that is trapped in large bathymetric depressions and freshwater that flows towards the depression, with the Haringvliet Estuary as a case study. The aim of the project is to determine the flow conditions that lead to flushing of the trapped saltwater from the bathymetric depressions in the Haringvliet Estuary and design a strategy accordingly. The study will be carried out by means of numerical modelling (Delft3D and/or OpenFOAM, depending on the scale of the problem) and by analyzing existing ADCP and CTD measurements, which have been carried out by Rijkswaterstaat and the University of Twente. This project will be part of the SALTISolutions programme, which includes many partners from academia, knowledge institutions, consultancy, and governmental organizations.

The EngD researcher will be based at the Marine and Fluvial Systems (MFS) group at the Department of Civil Engineering of the Faculty of Engineering Technology of the University of Twente (UT).

Please upload your application as soon as possible but latest August 23 2024 via the ‘Apply now’ button. Your application should include:

• a cover letter (emphasizing your specific interest, motivation and qualifications)
• a detailed CV
• an academic transcript of B.Sc. and M.Sc. education with grades obtained and a publication list (if applicable)
• result of an English test (if you attended a non-English taught MSc program)
• contact details of 2 referees

Since only three documents can be uploaded per application, please combine documents if needed.

The project will start as soon as possible after a suitable candidate is found, which may be before the deadline of applying. An interview will be part of the selection procedure; interviews are planned on 23 August and 30 August.

For more information about the position, you may contact Dr. Vasileios Kitsikoudis ([email protected] , +31 53 489 9910) or Prof. Suzanne Hulscher ([email protected], + 31 53 489 4256).

The Faculty of Engineering Technology (ET) engages in education and research of Mechanical Engineering, Civil Engineering and Industrial Design Engineering. We enable society and industry to innovate and create value using efficient, solid and sustainable technology. We are part of a ‘people-first' university of technology, taking our place as an internationally leading center for smart production, processes and devices in five domains: Health Technology, Maintenance, Smart Regions, Smart Industry and Sustainable Resources. Our faculty is home to about 2,900 Bachelor's and Master's students, 550 employees and 150 PhD candidates. Our educational and research programmes are closely connected with UT research institutes Mesa+ Institute, TechMed Center and Digital Society Institute.