Projected Responses of Tidal Dynamics in the North Sea to Sea-Level Rise and Morphological Changes in the Wadden Sea

This study explores the projected responses of tidal dynamics in the North Sea induced by the interplay between plausible projections of sea-level rise (SLR) and morphological changes in the Wadden Sea. This is done in order to gain insight into the casual relationships between physical drivers and hydro-morphodynamic processes. To achieve this goal, a hydronumerical model of the northwest European shelf seas (NWES) was set-up and validated. By implementing a plausible set of projections for global SLR (SLRRCP8.5 of 0.8 m and SLRhigh−end of 2.0 m) by the end of this century and beyond, the model was run to assess the responses of the regional tidal dynamics. In addition, for each considered SLR, various projections for cumulative rates of vertical accretion were applied to the intertidal flats in the Wadden Sea (ranging from 0 to 100% of projected SLR). Independent of the rate of vertical accretion, the spatial pattern of M2 amplitude changes remains relatively stable throughout most of the model domain for a SLR of 0.8 m. However, the model shows a substantial sensitivity toward the different rates of vertical accretion along the coasts of the Wadden Sea, but also in remote regions like the Skagerrak. If no vertical accretion is assumed in the intertidal flats of the Wadden Sea, the German Bight and the Danish west coast are subject to decreases in M2 amplitudes. In contrast, those regions experience increases in M2 amplitudes if the local intertidal flats are able to keep up with the projected SLR of 0.8 m. Between the different scenarios, the North Frisian Wadden Sea shows the largest differences in M2 amplitudes, locally varying by up to 14 cm. For a SLR of 2.0 m, the M2 amplitude changes are even more amplified. Again, the differences between the various rates of vertical accretion are largest in the North Frisian Wadden Sea (> 20 cm). The local distortion of the tidal wave is also significantly different between the scenarios. In the case of no vertical accretion, tidal asymmetry in the German estuaries increases, leading to a potentially enhanced sediment import. The presented results have strong implications for local coastal protection strategies and navigation in adjacent estuaries. © Copyright © 2021 Jordan, Visscher and Schlurmann

Modelling dynamic plume behaviour

Follow the link to watch the presentation: https://vimeo.com/664335037/aeb71642c

Wake length of an artificial seagrass meadow: a study of shelter and its feasibility for restoration

Seagrasses are essential marine ecosystems for which restoration has proven challenging due to increased hydrodynamic stress. This study aims to analyze the flow alteration induced by an artificial seagrass (ASG) meadow by characterizing its wake effect through a shelter distance and thus yield guidance for seagrass restoration projects. Here, we define shelter distance as the longitudinal extent behind a meadow, with respect to the flow direction, where seagrass is protected and can hence grow successfully. Flume experiments were conducted for submerged meadows with three different lengths at constant canopy height, shoot density and water depth, and three different cross-section-averaged longitudinal flow velocities measured with state-of-the-art Particle Image Velocimetry (PIV). For the tested meadow morphology and hydrodynamic conditions, meadow length played a less important role regarding shelter distance, while incident flow velocity and effective canopy height governed the wake effect. Incident velocities 2 m behind the meadow, whereas higher velocities led to a reduced shelter distance ranging from 20-40 cm. ASG additionally produced an upwelling effect on the vertical distribution of the velocity profile observed along the wake, regardless of meadow length and incident velocity. Our results suggest that restoration projects should aim for areas of low flow, where currents induced by tidal or wind waves are less pronounced in order to activate larger shelter distances

Multi-, inter- and transdisciplinarity in challenge-based engineering education

Challenge-based learning (CBL) offers students in engineering programmes an opportunity to develop communicative and collaborative skills, apply disciplinary knowledge and develop boundary-crossing competencies. Mono-disciplinary approaches to CBL are generally regarded too limited, but whether multi-disciplinary, interdisciplinary, or transdisciplinary approaches should be used is open to discussion. Often, these concepts are used interchangeably, but there are notable differences. In literature, knowledge integration is mostly mentioned to make a distinction, but because of difficulties in applying this concept to education, we focus on tangible differences in educational practices, related to learning objectives, assessment, and the design of challenges. The different forms of CBL are illustrated by three case-studies carried out at a research university in the Netherlands. We found similarities, but also some subtle differences between multi-, inter- and transdisciplinary approaches to CBL. Multidisciplinary CBL projects are relatively pre-structured, with an indication of the knowledge that is to be applied, deepened, or combined. Interdisciplinary CBL is more open-ended, with students made responsible for connecting their disciplinary backgrounds to the project and for integrating disciplinary perspectives. Transdisciplinary CBL focuses more on impact than on integrating disciplinary contributions. Challenges are open-ended from a content and stakeholder perspective, while structure emerges in the interactions between students, teachers and stakeholders. Which form of CBL can best be employed in a course or programme is dependent on the intended learning objectives. Educators should be aware of tradeoffs and of the specific teacher competences required to design and support these different forms of CBL.</p

SWITCH city facilitated progress analysis: Cali

This report aims at providing an evaluation of the Learning Alliance (LA) process in Cali, Colombia, after 17 months from its inception. In fact, Cali has become a SWITCH demonstration city only at the beginning of 2008. Until then, Cali had only been a SWITCH case study. The establishment of the LA started de facto in April 2007. The relative magnitude of the impact achieved so far by the local LA has to be seen in the light of its limited duration

Robust methods for the decomposition and interpretation of compound dunes applied to a complex hydromorphological setting

Underwater dunes are a morphological feature that are explored by marine scientists and coastal engineers alike. This study presents new methodologies in order to simplify bedform identification and morphodynamic analyses. Specifically, subaqueous compound dunes are decomposed with a simple yet extensive tracking algorithm, which relies on a repeated evaluation of unfiltered bed elevation profiles according to five predefined length classes. In a second step, morphological trends are assessed in the form of bed migration rates, bed slope asymmetries and net sediment changes, in which all parameters are referred to equidistant sections of the examined fairway stretch. This integrated approach not only avoids the challenges in weighting the varying size and abundance of dunes of different scales but also ensures comparability between dune-specific and areal parameters, which significantly improves the interpretation of the morphological setting as a whole. The developed methods are applied to the Outer Jade fairway, an anthropogenically influenced and regularly maintained waterway in the German Bight, and allow scrutiny of spatio-temporal trends in this region. Based on a unique data set of 100 sequential high-quality echo-sounding surveys, various types of bedforms are identified, comprising large-scale primary as well as superimposing secondary dunes that are assumed to interfere with each other. Temporal trends show a long-term rise of the troughs of major bedforms and constant maximum crest elevations near the official maintenance depth, which matches the observed long-term aggradation of sediments. The spatial distribution of integrated morphodynamic parameters reflects a previously described zone of primary dune convergence and facilitates the precise localization of this geophysical singularity. The presented findings both confirm the robustness of the proposed methodologies and, in return, enhance the understanding of morphological processes in the Outer Jade. © 2020 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons Ltd. © 2020 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons Lt

Develop An Interdisciplinary Course Using The Twente Interdisciplinarity Toolbox

The ability to engage in interdisciplinary research and problem-solving are essential skills for contemporary engineers, however designing and delivering effective learning opportunities to reach these ideals, is often not straightforward [1]. Educators are often faced with a plethora of challenges, and interdisciplinary courses often do not run as smoothly as disciplinary ones. In this workshop, the primary goal was to stimulate participants to consider a few common design scenarios modeled on real-life cases and to apply some of the main design concepts and questions employed by a new online platform the Twente Toolbox which aims to assist instructors with interdisciplinary course design. Participants were asked to make certain design choices in response to the cases within teams. The toolbox, funded by the Netherlands Initiative for Education Research (NRO) and developed by researchers at the University of Twente (interdisciplinary-education.utwente.nl) maps out different interdisciplinary course design structures, skill targets and learning goals. These are linked to specific in-class student tasks and assessment tools, which help students achieve those learning goals. In the session, participants were directed to relevant sections within the toolbox that would help inform design decisions of participants

Multi-, inter- and transdisciplinarity in challenge-based engineering education

Challenge-based learning (CBL) offers students in engineering programmes an opportunity to develop communicative and collaborative skills, apply disciplinary knowledge and develop boundary-crossing competencies. Mono-disciplinary approaches to CBL are generally regarded too limited, but whether multi-disciplinary, interdisciplinary, or transdisciplinary approaches should be used is open to discussion. Often, these concepts are used interchangeably, but there are notable differences. In literature, knowledge integration is mostly mentioned to make a distinction, but because of difficulties in applying this concept to education, we focus on tangible differences in educational practices, related to learning objectives, assessment, and the design of challenges. The different forms of CBL are illustrated by three casestudies carried out at a research university in the Netherlands. We found similarities, but also some subtle differences between multi-, inter- and transdisciplinary approaches to CBL. Multidisciplinary CBL projects are relatively pre-structured, with an indication of the knowledge that is to be applied, deepened, or combined. Interdisciplinary CBL is more open-ended, with students made responsible for connecting their disciplinary backgrounds to the project and for integrating disciplinary perspectives. Transdisciplinary CBL focuses more on impact than on integrating disciplinary contributions. Challenges are open-ended from a content and stakeholder perspective, while structure emerges in the interactions between students, teachers and stakeholders. Which form of CBL can best be employed in a course or programme is dependent on the intended learning objectives. Educators should be aware of tradeoffs and of the specific teacher competences required to design and support these different forms of CBL