Sand bypassing

Planning, design, construction and monitoring of sand bypassing systems.

Construction of marine structures alters coastal processes and will typically disturb the equilibrium of adjacent beaches by partially or fully blocking the natural sediment pathway.

PRDW has extensive coastal engineering and numerical modelling experience which provides the basis for understanding coastal processes (waves, wind, currents) and the influence of marine structures.

Changes in beach equilibrium or plan shape resulting from marine structures are often dealt with reactively when accretion updrift of a structure starts affecting:

  • Entrance channel navigability
  • Water quality at cooling water inlets
  • Beach widths for public amenities, etc.

And / or erosion downdrift starts affecting:

  • Property
  • Marine structures
  • Beach widths

Dredging of the accreting beach is then implemented and material is fed to the eroding beach or shoreline defence structures are built on the eroding beach. Alternatively the beaches are allowed to re-align.

A more pro-active approach is to incorporate some form of sand bypassing system in the design of the marine facility. This can only be done with a sound understanding of the coastal processes. PRDW have undertaken numerous sediment process and sand bypassing related studies and designs to address:

  • Creation of new beach amenities
  • Stabilisation and restoration of existing beach amenities
  • Security of cool, calm, sediment free water for power station cooling
  • Mobile and fixed sand bypassing systems

Each sand bypassing system is unique, designed to suit site specific coastal processes, marine infrastructure and environmental constraints by a multi-disciplinary team with expertise in coastal processes, coastal engineering, marine structures, MEPI, slurry and clear water hydraulics. PRDW retains all this expertise in-house. On complex projects, PRDW will sub-consult specialist input in the areas of MEPI and slurry hydraulics.