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  • A new tool to help our coastal engineers design stable artificial beaches

    Beach design and management tool
  • Beach design and management tool
  • Beach design and management tool
  • Beach design and management tool
  • Beach design and management tool

Beach design and management tool

HR Wallingford has developed a new software package to help our coastal engineers design stable artificial beaches. The Beach Design and Management Tool (BDMaT) allows engineers to apply the necessary parabolic equations computationally. This saves heavy number-crunching and has the additional advantage of providing a visual display of results.

When designing any artificial beach it is desirable to avoid, or minimise, future maintenance commitments by placing the initial beach plan-shape so that it remains in equilibrium given the incident wave climate. Headland bays, or embayments, where a sandy beach is held between two erosion resistant headlands, tend to evolve to a stable beach plan-shape with little movement of the beach contours over time.

The first stage in development of the tool involved an extensive literature review. We looked at the range of empirical bay shape equations that have been derived to fit curves to the shoreline planform of headland bay beaches. The most suitable equation for evaluating beach stability and predicting shoreline changes arising from structures built on a curved beach was the parabolic bay shape equation developed by Hsu and Evans (1989). The literature review indicated the limitations in the use of this equation, but found that it was still applicable, combined with engineering judgement, in the design and assessment of headland bays.

Historical application of this equation has largely been in manual form - tracing the calculated bay shape on a map or aerial photograph following hand calculations. Though straightforward, the process is repetitive and laborious.  BDMaT helps to overcome this limitation.

We can use BDMaT to calculate the idealised shoreline planform of a headland-bay beach in static equilibrium based on the parabolic equation. We can then present the results graphically within GIS, overlaying an image or map of the existing beach coastline.

BDMaT allows the stability of a headland-bay beach to be assessed visually, by comparing the existing shoreline periphery with the static equilibrium planform. The software can also be used to assist with the design of proposed artificial beaches, offering an intuitive environment with simple inputs and instant visualisation of results.  BDMaT provides HR Wallingford with a valuable tool for practical application on waterfront developments, shoreline protection and coastal management.

Authors

Jonathan Kemp, Hubert Bast, Tom Coates


Keywords

Stable beach assessment; beach design; coastal structures.


Completed

2007


References

Hsu and Evans (1989) Parabolic bay shapes and applications, Proceedings of Institution of Civil Engineers, 2,557-570.

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