Year 2 – year 6

University of Twente

This WP contains two main elements.

The PhD candidate will study the grain-size effect on coastal sand nourishment morphodynamics, and the underlying sediment sorting processes. This will be realized by a unique combination of field observations (the dedicated Living Lab nourishment, WP 1; together with WP 2.1) and controlled, small-scale lab experiments. The lab experiments will be carried out in the wave-current flumes of Waterproof (Boechat Albernaz et al., 2022). These allow for studying the morphological evolution, as well as the underlying sand transport processes, in great detail for different nourishments designs, wave-current conditions and sand mixtures. These will be complemented by data from existing large-scale wave flume experiments (Van der Werf et al., 2019a). This fundamental understanding will lead to new sand transport model formulations that will be implemented in the numerical morphological models to be developed in WP 2.4. At the same time, the new lab data will provide a unique data-set to test how well these models are capable of reproducing carefully-measured nourishment morphodynamics.

The Post-Doc will focus on the practical aspects of using non-native sediments for coastal nourishments, which would be different from current nourishment practice in The Netherlands. This includes ecological aspects, legal aspects (permits), implementation issues (e.g. sediment availability, shipping distance), and societal acceptance of such a different nourishment practice in concert with WP 2.2 (ecology), WPs 3.1-3.3 (user needs and perspectives; social cost and benefits) and WP 4 (development of sustainable sand nourishment strategies).

Task 2.3a Analysis of field data to understand the nourishment sediment sorting processes (Living Lab, WP 1)
Task 2.3b Wave-flume experiments to systematically study the mixed sand nourishment morphodynamics
Task 2.3c Development of a practical model for mixed sand transport under the combined wave-current action
Task 2.3d Analysis of the costs, benefits and feasibility to use non-native sediments for coastal nourishments

WaterProof was and will be actively involved in the design and execution of the research, in particular related to experiments in their wave-current flumes (Task 2.3b). Together with the other consultants, in particular Royal HaskoningDHV and Svašek Hydraulics, they will also be involved in developing, testing and application of the newly-developed practical sand transport model (Task 2.3c). All stakeholders will be involved to determine the costs, benefits and feasibility to use non-native sediments for coastal nourishments (Task 2.3d).

This WP will result in verified experience and understanding of the behavior of non-native sediments for coastal nourishments (Scientific breakthrough). It contributes to an improved understanding and modeling of the coastal ecosystem response to SLR and sand nourishments on a decadal time-scale (Output). This supports the discussions among stakeholders to potentially use other types of sands for coastal nourishments, which could find its way to coastal nourishment practice (Outcomes). This is necessary to co-create multifunctional sand nourishment strategies for resilient dynamic coastal landscapes with high socio-economic and natural values (Societal Impact). The data from the wave-flume experiments will be organized in a data-set that will be published open access. The new sand transport formula will be open source, such that it is generally available to foster improvements of morphological model predictions worldwide (Scientific Impact).

[Here the key results of this WP will be presented.]