Exploring Marine and Aeolian Controls on Coastal Foredune Growth Using a Coupled Numerical Model

Coastal landscape change represents aggregated sediment transport gradients from spatially and temporally variable marine and aeolian forces. Numerous tools exist that independently simulate subaqueous and subaerial coastal profile change in response to these physical forces on a range of time scales. In this capacity, coastal foredunes have been treated primarily as wind-driven features. However, there are several marine controls on coastal foredune growth, such as sediment supply and moisture effects on aeolian processes. To improve understanding of interactions across the land-sea interface, here the development of the new Windsurf-coupled numerical modeling framework is presented. Windsurf couples standalone subaqueous and subaerial coastal change models to simulate the co-evolution of the coastal zone in response to both marine and aeolian processes. Windsurf is applied to a progradational, dissipative coastal system in Washington, USA, demonstrating the ability of the model framework to simulate sediment exchanges between the nearshore, beach, and dune for a one-year period. Windsurf simulations generally reproduce observed cycles of seasonal beach progradation and retreat, as well as dune growth, with reasonable skill. Exploratory model simulations are used to further explore the implications of environmental forcing variability on annual-scale coastal profile evolution. The findings of this work support the hypothesis that there are both direct and indirect oceanographic and meteorological controls on coastal foredune progradation, with this new modeling tool providing a new means of exploring complex morphodynamic feedback mechanisms

The LifeLines Cohort Study:Prevalence and treatment of cardiovascular disease and risk factors

AbstractBackgroundThe LifeLines Cohort Study is a large three-generation prospective study and Biobank. Recruitment and data collection started in 2006 and follow-up is planned for 30years. The central aim of LifeLines is to understand healthy ageing in the 21st century. Here, the study design, methods, baseline and major cardiovascular phenotypes of the LifeLines Cohort Study are presented.Methods and resultsBaseline cardiovascular phenotypes were defined in 9700 juvenile (8–18years) and 152,180 adult (≥18years) participants. Cardiovascular disease (CVD) was defined using ICD-10 criteria. At least one cardiovascular risk factor was present in 73% of the adult participants. The prevalence, adjusted for the Dutch population, was determined for risk factors (hypertension (33%), hypercholesterolemia (19%), diabetes (4%), overweight (56%), and current smoking (19%)) and CVD (myocardial infarction (1.8%), heart failure (1.0%), and atrial fibrillation (1.3%)). Overall CVD prevalence increased with age from 9% in participants<65years to 28% in participants≥65years. Of the participants with hypertension, hypercholesterolemia and diabetes, respectively 75%, 96% and 41% did not receive preventive pharmacotherapy.ConclusionsThe contemporary LifeLines Cohort Study provides researchers with unique and novel opportunities to study environmental, phenotypic, and genetic risk factors for CVD and is expected to improve our knowledge on healthy ageing. In this contemporary Western cohort we identified a remarkable high percentage of untreated CVD risk factors suggesting that not all opportunities to reduce the CVD burden are utilised

ICON.NL: coastline observatory to examine coastal dynamics in response to natural forcing and human interventions

In the light of challenges raised by a changing climate and increasing population pressure in coastal regions, it has become clear that theoretical models and scattered experiments do not provide the data we urgently need to understand coastal conditions and processes. We propose a Dutch coastline observatory named ICON.NL, based at the Delfland Coast with core observations focused on the internationally well-known Sand Engine experiment, as part of an International Coastline Observatories Network (ICON). ICON.NL will cover the physics and ecology from deep water to the dunes. Data will be collected continuously by novel remote sensing and in-situ sensors, coupled to numerical models to yield unsurpassed long-term coastline measurements. The combination of the unique site and ambitious monitoring design enables new avenues in coastal science and a leap in interdisciplinary research

Assessing sandy beach width variations on intertidal time scales using permanent laser scanning

[EN] Coastal zones are highly dynamic, and their topography is subject to constant deformation. These deformations are governed by sediment transports that are forced by environmental conditions of waves, tides and wind which result in topographic changes at various spatial and temporal scales. In the view of climate change and intensification of extreme weather events, it is important for coastal management to monitor the deformation and coastal topography with high accuracy. To demonstrate a novel way of deriving these deformations and of analyzing the underlying processes, we use permanent laser scanning (PLS) to monitor part of the typical urban coastal beach in Noordwijk, The Netherlands. A laser scanner permanently installed on a hotel building acquired one 3D point cloud of the sandy beach and dunes every hour, continuously, for a duration of two years. The resulting spatio-temporal data set consists of ~ 15 000 point clouds and contains the evolution of a section of the coast of ~ 1 km length at great detail. The elevation changes are observed at centimeter level, allowing to monitor even small scale and slow processes. However, this information is not readily available from the extensive data set. By deriving digital elevation models (DEMs) from each point cloud and collecting elevation data as time series per spatial grid cell, we structure the data in an efficient way. We use the DEMs to estimate two parameters describing the coastal deformation, beach width and intertidal width. We also extract the shoreline at low and high tide for a part of the data set and estimate beach width and intertidal width from them. We find that heavy storms influence the location of the shoreline and the intertidal width in particular. Ultimately, the estimated beach width and intertidal width at high temporal frequency (monthly) and with high spatial accuracy (meters) helps coastal management to improve the understanding of coastal deformation processes.This research has been supported by the Netherlands Organization for Scientific Research (NWO, grant no. 16352) as part of the Open Technology Programme and by Rijkswaterstaat (Dutch Ministry of Infrastructure and Water Management).Kuschnerus, M.; Lindenbergh, R.; De Vries, S. (2023). Assessing sandy beach width variations on intertidal time scales using permanent laser scanning. Editorial Universitat Politècnica de València. 113-119. https://doi.org/10.4995/JISDM2022.2022.1372911311

The influence of the Sand Engine of the Delfland coastal cell

The Sand Engine is an example of a feeder nourishment that is intended to nourish coastal systems. This strategy is based on placing sediments highly concentrated at one location, from which it is expected to spread alongshore over large distances on decadal timescales. Here the morphological development of the Sand Engine mega feeder nourishment and the adjacent coastal sections is presented. This study is based on 37 high-resolution topographical surveys, spanning a coastal cell of 17 km alongshore. These data are explored to examine the alongshore spreading in the first five years after construction in 2011, as well as the response at different depth contours in the coastal profile. The analysis shows that the highly concentrated nourishment supplies sediment to a stretch of coast that is several times the initial length of the nourishment, as the size of the Sand Engine peninsula increased from 2.2 to 5.8km alongshore. The plan-form shape of the peninsula is found to gradually extend alongshore, while reducing in cross-shore extent. This behaviour is found to vary strongly with depth contours. The strongest response was found around the mean sea level iso-bath in contrast to the deeper parts and Aeolian parts of the Sand Engine. This variability in response over depth results in different profile slope development in accretive and erosive areas. In coastal sections which are eroding the sub-tidal slope decreases, while accretive profiles experience a profile slope increment over time. The cross shore extent of the morphologic response shows limited morphodynamic activity below the -8m NAP depth contour and confirms earlier assessments of closure depth at this coast. The current findings at the Sand Engine imply that mega feeder nourishments can be beneficial to the sediment budget of a larger coastal cell. However, volumes that are deposited around or below the depth of closure (around 15 % for the Sand Engine) may react on much longer time-scales than intended. Therefore, the feeding characteristics of mega feeder nourishments on time-scales of years should be assessed using the nourished volumes above the depth of closure rather than the total volume.Abstract to the presentation held on the NCK days 2018 in Haarlem, the Netherlands.status: publishe

Aeolian sediment transport on a beach with a varying sediment supply

Variability in aeolian sediment transport rates have traditionally been explain by variability in wind speed. Although it is recognised in literature that limitations in sediment supply can influence sediment transport significantly, most models that predict aeolian sediment transport attribute a dominant role to the magnitude of the wind speed. In this paper it is proposed that spatio-temporal variability of aeolian sediment transport on beaches can be dominated by variations in sediment supply rather than variations in wind speed.A new dataset containing wind speed, direction and sediment transport is collected during a 3. day field campaign at Vlugtenburg beach, The Netherlands. During the measurement campaign, aeolian sediment transport varied in time with the tide while wind speed remained constant. During low tide, measured transport was significantly larger than during high tide. Measured spatial gradients in sediment transport at the lower and upper beaches during fairly constant wind conditions suggest that aeolian sediment transport on beaches may be partly governed by the spatial variability in sediment supply, with relatively large supply in the intertidal zone when exposed and small supply on the upper beach due to sorting processes. The measurements support earlier findings that the intertidal zone can be significant source of sediment for sediment transport on beaches.Both a traditional cubic model (with respect to the wind speed) and a newly proposed linear model are fitted to the field data. The fit quality of both types of models are found to be similar