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Comparing Hard and Soft Engineering Solutions for Marina Inlet Sedimentation and Coastal Erosion at Blankenberge and Wenduine, Belgium

2020; Taylor & Francis; Linguagem: Inglês

10.1680/cm.65147.087

1521-0421

Annelies Bolle, Leen Baelus, E. Kragiopoulou, Elias Van Quickelborne, Thijs Lanckriet,

Environmental Engineering and Cultural Studies

: Abstract Blankenberge and Wenduine are two neighbouring Belgian coastal towns that are both experiencing morphological issues. The access channel to the Blankenberge marina is constrained by two low jetties and experiences sedimentation due to littoral drift. Less than three kilometres to the west, Wenduine is located at a breakpoint in coastline orientation and experiences structural beach erosion. A feasibility study was performed to investigate different solutions for both issues, wherein eleven alternative solutions were simulated using numerical models of morphodynamics over 1-5 years (XBeach), hydrodynamics (XBeach) and wave penetration (MIKE 21 BW). Based on the simulations, the alternatives were compared for their effectiveness in reducing the erosion/sedimentation issues, impact on nautical access to the marina, swimmer safety, flood protection, ecology, cost, and scenic impacts. Based on workshop discussions with stakeholders, the optimal solution was selected. For Blankenberge, the selected measure consists of raising and extending the western jetty in combination with a buffer zone west of the jetty. For Wenduine, the selected solution consists of constructing 5 groynes, in order to trap sediment in the current erosional hotspot and extend the lifespan of the beach nourishments. A detailed cost calculation shows that the proposed groyne field at Wenduine, a hard engineering measure, is expected to be more cost-effective than the current nourishment strategy, since it realigns the equilibrium coastline with the hinterland.