The Morphology of the Dutch Shoreface Between Hook of Holland and Den Helder (The Netherlands)

Wiersma, J.; Alphen, J. S. L. J. Van

doi:10.1007/978-94-015-7762-5_9

Cited by 4 publications

(5 citation statements)

References 4 publications

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“…The tidal current velocity during flood tide is~0.7 m/s, with lower values during the ebb tide. This result confirms previous studies from Wiersma and Van Alphen (1987) and Short (1992).…”

Section: Tidal Currentssupporting

confidence: 95%

“…Wave conditions are mild, with significant wave heights of 1.3 m and wave periods of 6.4 seconds, respectively (Wijnberg, 2002), with significant seasonal variations between summer and winter, with winter waves higher. The beach is mesotidal, with a tidal range of 1.4-1.7 m (Wiersma and Van Alphen, 1987). The tidal current is a pronounced hydrodynamic feature at this site, where strong alongshore (tidal) velocity flows to the north during flood tide and to the south during ebb tide.…”

Section: Datamentioning

confidence: 98%

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Dynamic Modelling of Rip Currents for Swimmer Safety on a Wind-Sea–Dominated Mesotidal Beach

Sembiring

Dongeren

Winter

et al. 2015

Journal of Coastal Research

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Sembiring, L.; van Dongeren, A.; Winter, G., and Roelvink, D., 0000. Dynamic modelling of rip currents for swimmer safety on a wind-sea-dominated mesotidal beach. Journal of Coastal Research, 00(0), 000-000. Coconut Creek (Florida), ISSN 0749-0208.We apply the process-based model XBeach to predict bathymetrically controlled rip current flow occurrence, velocities and duration in the wind-sea-dominated environment of Egmond aan Zee, The Netherlands. The model is validated against data obtained during a 5-day field experiment with GPS-equipped floating drifters. Numerical model results show good agreement with data and simulate flow patterns that resemble the offshore flow through the rip channel and subsequent alongshore drift of the drifters. The average relative error of the drifter position is 0.15 and 0.19 for the crossshore and the alongshore position, respectively. Results from the numerical experiments suggest that the rip current intensity is tidally modulated. For the period of analysis, the rips are initiated approximately 5 hours before low tide, reaching a maximum speed during low tide, and becoming inactive 3 hours after low tide. Initiation and duration of the rip current is correlated to a ratio of~0.55 between offshore wave height and water depth over the bar. Further experiments with the numerical model show that at Egmond, drifters that are transported offshore by the rip current are unlikely to circulate back to the shore (with only a 14% return rate). Instead, they are ejected from the surf zone and advected alongshore, dependent on the direction of the tidal current. Without wave group forcing in the model (i.e. with a stationary wave resolving approach), the model's predictability decreases, which mostly affects the prediction of the spatial flow patterns. The rip current durations can still be predicted very well, whereas the rip current magnitude is underestimated. With wind stress forcing, the model's predictive skill increases for the alongshore flow when the wind speed is relatively high, but this is not the case for low wind conditions.

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“…The tidal current velocity during flood tide is~0.7 m/s, with lower values during the ebb tide. This result confirms previous studies from Wiersma and Van Alphen (1987) and Short (1992).…”

Section: Tidal Currentssupporting

confidence: 95%

Section: Datamentioning

confidence: 98%

Dynamic Modelling of Rip Currents for Swimmer Safety on a Wind-Sea–Dominated Mesotidal Beach

Sembiring

Dongeren

Winter

et al. 2015

Journal of Coastal Research

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“…The influence of the shoreface morphology on the evolution of the beach-dune system along the Holland coast during the last thousand years has been pointed out (Wiersma and van Alphen, 1988). Sand supplied from the shelf has led to the formation of the Younger Dune Sands between 1000 and 1900 AD and has produced a steepening of the nearshore gradient from 1:200 to 1:100 between 0 and 5 m water depth (Roep, 1984).…”

Section: Introductionmentioning

confidence: 99%

“…Cross-shore transport is held responsible for most of the progradation along the central part of the coast of Holland (Wiersma and van Alphen, 1988;Stive and Eysink, 1989). Erosion in the north is thought to be largely due to loss of sand to the Wadden Sea through the Texel inlet (Stive and Eysink, 1989).…”

Section: Introductionmentioning

confidence: 99%

Shoreline evolution of the Holland coast on a decadal scale

Guillén

Stive

Capobianco

1999

Earth Surf. Process. Landforms

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The decadal evolution of the dunefoot position along 120 km of the Holland coast is analysed. Firstly, a new definition of dunefoot is introduced based on hydrodynamic and morphologic considerations, which is not affected by local and instantaneous processes occurring immediately before the bathymetric survey. The dunefoot evolution over decadal scales indicates the existence of spatial and temporal oscillations in the shoreline position with magnitudes of 2±3 km length and a periodicity of 4±15 years. Two main controlling factors of this behaviour are identified: (1) influence of sub-aqueous bar systems, and (2) changes in the storm-wave conditions reaching the coast. Although the precise controlling processes of the relation between the dunefoot and the subaqueous profile still remain unclarified, we introduce the concept that the development of a morphological bar cycle requires a fixed amount of time-integrated forcing that is proportional to the cumulative effect of storm waves.Beach mobility along the Holland coast on decadal scales (10±20 m) is similar or lower than mobility introduced by storms or by seasonal cycles. However, it is important to consider these changes for the possible implications on the local vulnerability of the coast to extreme events.

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“…The Holland coast is presently prograding in the centre and retreating in the north and south. The progradation is interpreted to be the result of onshore sediment exchange from the shelf and shoreface to the surf zone (Wiersma & van Alphen 1988;Stive & de Vriend 1987;Stive 1989;Stive et al 1990). Retreat in the north is due to sediment loss through the Marsdiep Inlet to the Wadden Sea and in the south due to net northward longshore losses enhanced by the Rotterdam Waterway (Dijkman et al 1990;Stive et a/.1990;Van Rijn 1995).…”

Section: Study Areamentioning

confidence: 99%

Shoreface morphodynamics along the Holland Coast

Hinton

Nicholls

2007

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The morphodynamic behaviour of the shoreface of the Holland coast has been investigated over the medium-and large-scales (years to decades). This is a wave-dominated, uniform coastline backed by dunes and uninterrupted by tidal inlets. The work takes a data-orientated approach using the 'long' profiles in a data set extending over 32 years and covering 81 km of coast. These profiles are spaced every 1 km alongshore and extend to a maximum offshore distance of 3 km (approximately 16 m water depth).Previous work based upon cross-shore profiles suggests that there is a seaward limit to significant depth change, or activity, on the upper shoreface over the small-and mediumscales (termed 'depth of closure'). Examination of the data set shows that the middle and lower shoreface is also morphologically active in many instances, with the activity increasing with timescale. Many profiles exhibit closure on the upper shoreface, and then reopen on the middle/lower shoreface, exhibiting morphological activity. This deeper shoreface morphodynamics appears to be related to onshore supply of sand to the active zone. Hence, the analysis shows that the upper, middle and lower shoreface are coupled, as widely assumed, and has widespread significance for understanding long-term coastal evolution.

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The Morphology of the Dutch Shoreface Between Hook of Holland and Den Helder (The Netherlands)

Cited by 4 publications

References 4 publications

Dynamic Modelling of Rip Currents for Swimmer Safety on a Wind-Sea–Dominated Mesotidal Beach

Dynamic Modelling of Rip Currents for Swimmer Safety on a Wind-Sea–Dominated Mesotidal Beach

Shoreline evolution of the Holland coast on a decadal scale

Shoreface morphodynamics along the Holland Coast

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