Variations in storm-induced bed level dynamics across intertidal flats
Vet, P.L.M. de; Prooijen, B.C. van; Colosimo, I. ; Steiner, N. ; Ysebaert, T. ; Herman, P.M.J. ; Wang, Z.B. - \ 2020
Scientific Reports 10 (2020)1. - ISSN 2045-2322
Hydrodynamic forces on intertidal flats vary over a range of temporal and spatial scales. These spatiotemporal inhomogeneities have implications for intertidal flat morphodynamics and ecology. We determine whether storm events are capable of altering the long-term morphological evolution of intertidal flats, and unravel the contributions of tidal flow, wind-driven flow, waves, and water depth on inhomogeneities in bed level dynamics (bed level changes over ~days) across these areas. We complement decades of bed level measurements on eight intertidal flats in two estuaries in the Netherlands with an extensive 1-month field campaign on one of those flats. Across this intertidal flat, the hydrodynamics and morphodynamics of a storm event were captured, including the post-storm recovery. We show that individual events can persistently alter the morphological evolution of intertidal flats; magnitudes of some bed level changes are even comparable to years of continuous evolution. The morphological impacts of events are largely controlled by the relative timing of the forcing processes, and not solely by their magnitudes. Spatiotemporal variations in bed level dynamics of intertidal flats are driven by a combination of: (1) the inhomogeneous distributions of the hydrodynamic forcing processes (including the under-explored role of the wind); and (2) the linear proportionality between bed level dynamics and the local bed slope.
Sediment Disposals in Estuarine Channels Alter the Eco-Morphology of Intertidal Flats
Vet, P.L.M. de; Prooijen, B.C. van; Colosimo, I. ; Ysebaert, T. ; Herman, P.M.J. ; Wang, Z.B. - \ 2020
Journal of Geophysical Research: Earth Surface 125 (2020)2. - ISSN 2169-9003
ecology - estuaries - intertidal flats - morphology - sediment disposals - sediment management
Dredging of navigation channels in estuaries affects estuarine morphology and ecosystems. In the Western Scheldt, a two-channel estuary in the Netherlands, the navigation channel is deepened and the sediment is relocated to other parts of the estuary. We analyzed the response of an intertidal flat to sediment disposals in its adjacent channel. Decades of high-frequency monitoring data from the intertidal flat show a shift from erosion toward accretion and reveal a sequence of cascading eco-morphological consequences. We document significant morphological changes not only at the disposal sites, but also at the nearby intertidal flats. Disposals influence channel bank migration, driving changes in the evolution of the intertidal flat hydrodynamics, morphology, and grain sizes. The analyzed disposals related to an expansion of the channel bank, an increase in bed level of the intertidal flat, a decrease in flow velocities on this higher elevated flat, and locally a decrease in grain sizes. These changes in turn affect intertidal flat benthic communities (increased in quantity in this case) and the evolution of the adjacent salt marsh (retreated less or even expanded in this case). The shifts in evolution may occur years after dredged disposal begins, especially in zones of the flats farther away from the disposal locations. The consequences of sediment disposals that we identify stress the urgency of managing such interventions with integrated strategies on a system scale.
Dit gras helpt tegen klimaatverandering, maar van de EU mogen koeien het niet eten
Dijkstra, Jan - \ 2019
Beneficial use of dredged sediment to enhance salt marsh development by applying a ‘Mud Motor’
Baptist, Martin J. ; Gerkema, T. ; Prooijen, B.C. van; Maren, D.S. van; Regteren, M. van; Schulz, K. ; Colosimo, I. ; Vroom, J. ; Kessel, T. van; Grasmeijer, B. ; Willemsen, P. ; Elschot, K. ; Groot, A.V. de; Cleveringa, J. ; Eekelen, E.M.M. van; Schuurman, F. ; Lange, H.J. de; Puijenbroek, M.E.B. van - \ 2019
Ecological Engineering 127 (2019). - ISSN 0925-8574 - p. 312 - 323.
Building with Nature - Nature-based solutions - Cohesive sediment - Dredging - Salt marshes - intertidal flats
We test an innovative approach to beneficially re-use dredged sediment to enhance salt marsh development. A Mud Motor is a dredged sediment disposal in the form of a semi-continuous source of mud in a shallow tidal channel allowing natural processes to disperse the sediment to nearby mudflats and salt marshes. We describe the various steps in the design of a Mud Motor pilot: numerical simulations with a sediment transport model to explore suitable disposal locations, a tracer experiment to measure the transport fate of disposed mud, assessment of the legal requirements, and detailing the planning and technical feasibility. An extensive monitoring and research programme was designed to measure sediment transport rates and the response of intertidal mudflats and salt marshes to an increased sediment load. Measurements include the sediment transport in the tidal channel and on the shallow mudflats, the vertical accretion of intertidal mudflats and salt marsh, and the salt marsh vegetation cover and composition. In the Mud Motor pilot a total of 470,516 m 3
of fine grained sediment (D50 of ∼10 μm) was disposed over two winter seasons, with an average of 22 sediment disposals per week of operation. Ship-based measurements revealed a periodic vertical salinity stratification that is inverted compared to a classical estuary and that is working against the asymmetric flood-dominated transport direction. Field measurements on the intertidal mudflats showed that the functioning of the Mud Motor, i.e. the successful increased mud transport toward the salt marsh, is significantly dependent on wind and wave forcing. Accretion measurements showed relatively large changes in surface elevation due to deposition and erosion of layers of
watery mud with a thickness of up to 10 cm on a time scale of days. The measurements indicate notably higher sediment dynamics during periods of Mud Motor disposal. The salt marsh demonstrated significant vertical accretion though this has not yet led to horizontal expansion because there was more hydrodynamic stress than foreseen. In carrying out the pilot we learned that the feasibility of a Mud Motor depends on an assessment of additional travel time for the dredger, the effectiveness on salt marsh growth, reduced dredging volumes in a port, and many other practical issues. Our improved understanding on the transport processes in the channel and on the mudflats and salt marsh yields design lessons and guiding principles for future applications of sediment
management in salt marsh development that include a Mud Motor approach
The Importance of Combined Tidal and Meteorological Forces for the Flow and Sediment Transport on Intertidal Shoals
de Vet, P.L.M. ; van Prooijen, B.C. ; Schrijvershof, R.A. ; van der Werf, J.J. ; Ysebaert, T. ; Schrijver, M.C. ; Wang, Z.B. - \ 2018
Journal of Geophysical Research: Earth Surface 123 (2018)10. - ISSN 2169-9003 - p. 2464 - 2480.
hydrodynamics - intertidal area - morphology - numerical model - sediment transport - wind
Estuarine intertidal areas are shaped by combined astronomical and meteorological forces. This paper reveals the relative importance of tide, surge, wind, and waves for the flow and sediment transport on large intertidal shoals. Results of an intensive field campaign have been used to validate a numerical model of the Roggenplaat intertidal shoal in the Eastern Scheldt Estuary, the Netherlands, in order to identify and quantify the importance of each of the processes over time and space. We show that its main tidal creeks are not the cause for the dominant direction of the net flow on the shoal. The tidal flow over the shoal is steered by the water level differences between the surrounding channels. Also during wind events, the tidal flow (enhanced by surge) is dominant in the creeks. In contrast, wind speeds of order 40 times the typical tidal flow velocity are sufficient to completely alter the flow direction and magnitude on an intertidal shoal. This has significant consequences for the sediment transport patterns. Apart from this wind-driven flow dominance during these events, the wind also increases the bed shear stress by waves. For the largest intertidal part of the Roggenplaat, only ∼1–10% of the yearly transport results from the 50% least windy tides, even if the shoal is artificially lowered half the tidal range. This dominance of energetic meteorological conditions in the transports matches with field observations, in which the migration of the creeks and high parts of the shoal are in line with the predominant wind direction.
Richtlijn takbreuk populier : Landelijke richtlijn te gebruiken voor vervangingsplannen populieren in de stedelijke omgeving
Kuik, Fons van; Prooijen, Gerrit Jan van - \ 2018
Wageningen : Stichting Wageningen Research, Wageningen Plant Research (Wageningen Plant Research rapport 2018-04) - 19
In opdracht van de Intergemeentelijke Studiegroep Boomverzorging (ISB) is een richtlijn ontwikkeld die gebruikt kan worden bij het beoordelen van populieren. Deze richtlijn richt zich specifiek op het aspect takbreuk. Bij bepaalde typen populier kunnen ogenschijnlijk gezonde takken een verhoogd risico op takbreuk opleveren. Bij een periodieke boomveiligheidscontrole wordt doorgaans onvoldoende op deze specifieke problematiek gelet. Aanvullende kennis en informatie is noodzakelijk voor een goede beoordeling van populieren op dit risico. De richtlijn, die bestaat uit acht stappen, reikt hiervoor aanknopingspunten aan.
The ecosystem engineer Crassostrea gigas affects tidal flat morphology beyond the boundary of their reef structures
Walles, B. ; Salvador de Paiva, J. ; Prooijen, B. van; Ysebaert, T. ; Smaal, A.C. - \ 2015
Estuaries and coasts 38 (2015)3. - ISSN 1559-2723 - p. 941 - 950.
wadden sea - sediment dynamics - pacific oysters - native mussels - habitat - estuary - stabilization - enhancement - communities - adaptation
Ecosystem engineers that inhabit coastal and estuarine environments, such as reef building oysters, do not only stabilise the sediment within their reefs, but their influence might also extend far outside their reefs, affecting tidal flat morphology and protecting the surrounding soft-sediment environment against erosion. However, quantitative information is largely missing, and the spatially extended ecosystem engineering effects on the surrounding soft-sediment largely unstudied. To quantify this, we measured elevations around eleven natural Crassostrea gigas reefs occurring on tidal flats in the Oosterschelde estuary (the Netherlands). These tidal flats experience strong erosion as a consequence of human interventions in the system. Various reef sizes were chosen to test the proportional effects of reefs on tidal flat morphology. Measurements were used to create 3-dimensional surface maps to obtain properties of the reefs and the surrounding soft-sediment environment. The area of the oyster reefs ranged from 2 to 1,908 m2. Reef length varied between 1 and 61 m, reef width between 1 and 45 m, and reef height between 0.20 and 1.08 m. Reefs varied in shape, going from round shape structures to more elongated ones. We observed elevated areas (>5 cm elevation from the background intertidal slope) on the lee side of all reefs, caused by the interaction between the reef’s structure and locally prevailing wave conditions. The elevated area (i.e. the spatially extended ecosystem engineering effect) affected by the reef was of the same order of magnitude as the reef area. The elevated area was related to reef properties such as reef length, width, and height. Reef length, however, appeared to be the best predictor. These findings contribute to management solutions for coastal adaptation and protection. Our study clearly showed that oyster reefs not only protect the tidal flat under their footprint, but as well an area beyond the boundary of the reef
|Ecodynamic solutions for the protection of intertidal habitats: the use of oyster reefs
Ysebaert, T. ; Walles, B. ; Dorsch, C. ; Dijkstra, J. ; Troost, K. ; Volp, N. ; Prooijen, B. van; Vries, M. de; Herman, P. ; Hibma, A. - \ 2012
In: 104th Annual Meeting, Shellfisheries Association, Seattle, Washington, March 24–29, 2012 Washington : National Shellfisheries Association - p. 362 - 362.
Ecosystem engineering processes are relevant to many environmental problems and management concerns. Within the program ‘‘Building with Nature’’ (www.ecoshape.nl) we investigate the use of bivalve reefs as ecodynamic measures to protect tidal flats against erosion, which poses a serious problem in the Oosterschelde estuary (Netherlands). Bivalve reefs are ecosystem engineers that influence tidal flow and wave action and therefore modify sediment transport patterns. The development of such infrastructural solutions that aim for an integration with the natural environment can only be achieved through experimentation and learning-by-doing. Artificial oyster reefs were constructed in different erosional intertidal environments in the Oosterschelde. Reefs consist of gabions filled with oyster shells (Crassostrea gigas), offering a stable substrate that allows for the settlement of oysters, while minimizing shell loss. Monitoring results indicate that artificial reefs can develop into self-maintaining, living oyster reefs which stabilize tidal flats. Site-specific effects in reef development (e.g. recruitment of oyster larvae) and in sediment dynamics were observed. Knowledge about local hydromorphological conditions and a thorough understanding of the ecosystem engineering properties and habitat requirements of C. gigas are needed to implement this concept in management practices. We present the concept, monitoring and modeling results and derive design rules from these.
Perceiving Pure Evil: The Influence of Cognitive Load and Prototypical Evilness on Demonizing
Prooijen, J.W. van; Veer, E. van de - \ 2010
Social Justice Research 23 (2010)4. - ISSN 0885-7466 - p. 259 - 271.
social categorizations - punishment - judgment - justice
The present research sought to investigate the psychological dynamics underlying demonizing, that is, the tendency to see others as personifications of pure evilness. Building on an integrative theoretical framework, it is hypothesized that the extent to which a perpetrator matches prototypical expectations of evilness shapes demonizing responses to offenders particularly when cognitive resources are impaired. In two experiments, participants were asked to memorize either a difficult or an easy telephone number (cognitive load vs. control), and were then asked to evaluate a perpetrator who murdered a young woman (Experiment 1) or who kidnapped a child (Experiment 2). Results revealed that the extent to which the description of the perpetrator was consistent with a prototypical evilness scheme influenced demonizing particularly under conditions of cognitive load. It is concluded that impairment of cognitive resources increases the influence of prototypical evilness on demonizing
|Jaarboek Sociale Psychologie 2009
Prooijen, J.W. van; Renes, R.J. ; Derks, B. ; Stel, M. ; Vliek, M. - \ 2010
Groningen : Aspo Pers - ISBN 9789080893979 - 543 p.
Innovative highlights in the environmental impact assessment Maasvlakte 2
Ledden, M. ; Bolle, L.J. ; Boon, J. ; Borst, W. ; Prooijen, B. van; Ronde, J. de - \ 2008
In: Coastal engineering: proceedings of the 31st International Conference, August 31 - September 5, 2008, Hamburg, Germany. - Hamburg : ICCE - p. 4436 - 4448.
This paper highlights the innovations during the environmental impact assessment of the land reclamation (Maasvlakte 2) near the port of Rotterdam (The Netherlands). The construction of this new port area consists of two main activities: sand mining in the North Sea and land reclamation near the harbor entrance of Rotterdam. Various modeling studies have been carried out to assess the effects of the land reclamation and sand mining on the surrounding coastal waters. Three innovative developments are described in this paper: 1) a large-scale three-dimensional hydrodynamic model of the Southern North Sea with a very high resolution along the Dutch coast and in the Wadden Sea, 2) a new fish larvae model that takes account of the behavior of fish larvae in relation to the physical factors (eg. salinity, currents) and biological processes (eg. larval growth), and 3) a process-based model for the dispersion of mud in the North Sea that includes the exchange of mud to and from the sediment bed at various time scales (tide, spring-neap, seasons). Apart from describing these innovations, the paper also discusses the fruitful interactions between various disciplines and institutes, and the lessons learned from this extensive modeling effort
Interference of polychlorinated biphenyls in thyroid hormone metabolism: possible neurotoxic consequences in fetal and neonatal rats.
Morse, D.C. ; Koeter, H.B.W.M. ; Smits van Prooijen, A.E. ; Brouwer, A. - \ 1992
Chemosphere 25 (1992). - ISSN 0045-6535 - p. 165 - 168.