Observed Changes of a Mega Feeder Nourishment in a Coastal Cell: Five Years of Sand Engine Morphodynamics
Recently, <i>mega feeder nourishments</i> have been proposed as a new strategy to nourish sediment-starving beaches. This strategy involves the placement of a large, concentrated sediment volume at a single location along the coast. Wind, waves and currents act as the natural agents to s...
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| Format: | Article |
| Language: | English |
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MDPI AG
2021-01-01
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| Series: | Journal of Marine Science and Engineering |
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| Online Access: | https://www.mdpi.com/2077-1312/9/1/37 |
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| author | Bart Roest Sierd de Vries Matthieu de Schipper Stefan Aarninkhof |
| author_facet | Bart Roest Sierd de Vries Matthieu de Schipper Stefan Aarninkhof |
| author_sort | Bart Roest |
| collection | DOAJ |
| description | Recently, <i>mega feeder nourishments</i> have been proposed as a new strategy to nourish sediment-starving beaches. This strategy involves the placement of a large, concentrated sediment volume at a single location along the coast. Wind, waves and currents act as the natural agents to spread the sediment alongshore over the course of years to decades. This article presents the morphological development of the first full-scale implementation of this strategy, examining the 20 × 10<sup>6</sup> m<sup>3</sup><i>“Sand Engine”</i> feeder nourishment and its impact on adjacent coastal sections. The analysis is based on 37 high-resolution topographical surveys, executed in a 17 km coastal cell. These unique data describe the alongshore spreading in the first five years and the response at different elevations of the coastal profile. The analysis shows rapid transformation of the nourishment’s planform shape, changing rapidly into a smooth (Gaussian-like) shape which is gradually extending alongshore over time. Within five years, sediment has been distributed to a 5.8 km stretch of coast from the initial 2.2 km peninsula footprint. Changes in cross-shore and alongshore extent varied strongly over depth, with the strongest morphological response at the mean sea level (MSL) isobath and limited morphodynamic activity at deeper water, below −8 m MSL. This depth-dependent response has resulted in decreasing subtidal slopes in eroding areas, accretive areas contrastingly show a slope increment. These results yield important insights in nourished sediment mobility at different depths near the coast and distribution over a larger coastal cell. However, this single-design assessment cannot address the wide range of mega nourishment design parameters essential for morphological development of its coastal cell. This work suggests limiting cross-shore extent, since it is uncertain whether nourished sediment at deeper water will become active in the coastal system. A continuation of the current monitoring and future research might shed more light on this. |
| first_indexed | 2024-03-10T13:33:29Z |
| format | Article |
| id | doaj.art-fd6b28875c04402b84e7953115d75425 |
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| issn | 2077-1312 |
| language | English |
| last_indexed | 2024-03-10T13:33:29Z |
| publishDate | 2021-01-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Journal of Marine Science and Engineering |
| spelling | doaj.art-fd6b28875c04402b84e7953115d754252023-11-21T07:43:40ZengMDPI AGJournal of Marine Science and Engineering2077-13122021-01-01913710.3390/jmse9010037Observed Changes of a Mega Feeder Nourishment in a Coastal Cell: Five Years of Sand Engine MorphodynamicsBart Roest0Sierd de Vries1Matthieu de Schipper2Stefan Aarninkhof3Faculty of Civil Engineering and Geosciences, Department of Hydraulic Engineering, Delft University of Technology, P.O. Box 5048, 2600 GA Delft, The NetherlandsFaculty of Civil Engineering and Geosciences, Department of Hydraulic Engineering, Delft University of Technology, P.O. Box 5048, 2600 GA Delft, The NetherlandsFaculty of Civil Engineering and Geosciences, Department of Hydraulic Engineering, Delft University of Technology, P.O. Box 5048, 2600 GA Delft, The NetherlandsFaculty of Civil Engineering and Geosciences, Department of Hydraulic Engineering, Delft University of Technology, P.O. Box 5048, 2600 GA Delft, The NetherlandsRecently, <i>mega feeder nourishments</i> have been proposed as a new strategy to nourish sediment-starving beaches. This strategy involves the placement of a large, concentrated sediment volume at a single location along the coast. Wind, waves and currents act as the natural agents to spread the sediment alongshore over the course of years to decades. This article presents the morphological development of the first full-scale implementation of this strategy, examining the 20 × 10<sup>6</sup> m<sup>3</sup><i>“Sand Engine”</i> feeder nourishment and its impact on adjacent coastal sections. The analysis is based on 37 high-resolution topographical surveys, executed in a 17 km coastal cell. These unique data describe the alongshore spreading in the first five years and the response at different elevations of the coastal profile. The analysis shows rapid transformation of the nourishment’s planform shape, changing rapidly into a smooth (Gaussian-like) shape which is gradually extending alongshore over time. Within five years, sediment has been distributed to a 5.8 km stretch of coast from the initial 2.2 km peninsula footprint. Changes in cross-shore and alongshore extent varied strongly over depth, with the strongest morphological response at the mean sea level (MSL) isobath and limited morphodynamic activity at deeper water, below −8 m MSL. This depth-dependent response has resulted in decreasing subtidal slopes in eroding areas, accretive areas contrastingly show a slope increment. These results yield important insights in nourished sediment mobility at different depths near the coast and distribution over a larger coastal cell. However, this single-design assessment cannot address the wide range of mega nourishment design parameters essential for morphological development of its coastal cell. This work suggests limiting cross-shore extent, since it is uncertain whether nourished sediment at deeper water will become active in the coastal system. A continuation of the current monitoring and future research might shed more light on this.https://www.mdpi.com/2077-1312/9/1/37sand enginemega nourishmentfeeder nourishmentnourishment designcross-shore adjustment |
| spellingShingle | Bart Roest Sierd de Vries Matthieu de Schipper Stefan Aarninkhof Observed Changes of a Mega Feeder Nourishment in a Coastal Cell: Five Years of Sand Engine Morphodynamics Journal of Marine Science and Engineering sand engine mega nourishment feeder nourishment nourishment design cross-shore adjustment |
| title | Observed Changes of a Mega Feeder Nourishment in a Coastal Cell: Five Years of Sand Engine Morphodynamics |
| title_full | Observed Changes of a Mega Feeder Nourishment in a Coastal Cell: Five Years of Sand Engine Morphodynamics |
| title_fullStr | Observed Changes of a Mega Feeder Nourishment in a Coastal Cell: Five Years of Sand Engine Morphodynamics |
| title_full_unstemmed | Observed Changes of a Mega Feeder Nourishment in a Coastal Cell: Five Years of Sand Engine Morphodynamics |
| title_short | Observed Changes of a Mega Feeder Nourishment in a Coastal Cell: Five Years of Sand Engine Morphodynamics |
| title_sort | observed changes of a mega feeder nourishment in a coastal cell five years of sand engine morphodynamics |
| topic | sand engine mega nourishment feeder nourishment nourishment design cross-shore adjustment |
| url | https://www.mdpi.com/2077-1312/9/1/37 |
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