Print Email Facebook Twitter Observed Changes of a Mega Feeder Nourishment in a Coastal Cell: Five Years of Sand Engine Morphodynamics Title Observed Changes of a Mega Feeder Nourishment in a Coastal Cell: Five Years of Sand Engine Morphodynamics Author Roest, Lambertus W.M. (TU Delft Coastal Engineering; Katholieke Universiteit Leuven) de Vries, S. (TU Delft Coastal Engineering) de Schipper, M.A. (TU Delft Coastal Engineering) Aarninkhof, S.G.J. (TU Delft Hydraulic Engineering) Department Hydraulic Engineering Date 2021 Abstract Recently, mega feeder nourishments 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 × 106 m3“Sand Engine” 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. Subject Cross-shore adjustmentFeeder nourishmentMega nourishmentNourishment designSand engine To reference this document use: http://resolver.tudelft.nl/uuid:583f3d2b-a77f-4744-84bf-94f8c6fe180e DOI https://doi.org/10.3390/jmse9010037 ISSN 2077-1312 Source Journal of Marine Science and Engineering, 9 (1), 1-24 Part of collection Institutional Repository Document type journal article Rights © 2021 Lambertus W.M. Roest, S. de Vries, M.A. de Schipper, S.G.J. Aarninkhof Files PDF jmse_09_00037_v2.pdf 16.14 MB Close viewer /islandora/object/uuid%3A583f3d2b-a77f-4744-84bf-94f8c6fe180e/datastream/OBJ/view