An approach to medium-term coastal morphological modelling
UNESCO-IHE PhD Thesis
By Giles Lesser
CRC Press – 2010 – 250 pages
CRC Press – 2010 – 250 pages
This thesis presents the implementation of fully three-dimensional sediment transport and morphological updating formulations within a proven three-dimensional hydrodynamic flow solver. The thesis briefly discusses the formulations used to model both suspended and bed-load transport of non-cohesive sediment, and describes the implementation of a morphological updating scheme which incorporates novel approaches to morphological acceleration and dry bank erosion. Approaches used to model the three-dimensional effects of waves on coastal hydrodynamics and of three-dimensional currents on waves are also discussed.
Results of several validation studies are presented and the model is shown to perform well in a series of simplified theoretical, laboratory, and full scale test cases. Application of the model and acceleration techniques to the complex and dynamic entrance to Willapa Bay, WA, USA is also discussed. Model processes are validated against the results of an extensive field measurement campaign, and diagnostic morphological model simulations are performed for two historical periods of contrasting morphological development.
Input reduction and morphological acceleration techniques used to perform 5-year simulations of Willapa Bay are critically analysed and a new generic method to select a representative morphological tide for coastal environments containing significant diurnal tidal energy is presented.
1.3 Thesis Structure and Approach
2 A Three-dimensional Morphological Model
2.4 Suspended Sediment Transport
2.5 Bed-load Sediment Transport
3 Model Validation
3.2 Comparison with Analytical Solutions
3.3 Comparison with Physical Measurements
3.4 Comparison with Other Numerical Models
4 Medium-term Modelling of Willapa Bay
4.2 Field Measurement Campaign
4.3 Establishment of a Morphological Model
4.4 Morphological Model Analysis
4.5 Morphological Modelling Conclusions
5 Morphological Acceleration Techniques
5.1 Approaches and Considerations
6.1 Devloping a 3D Morphological Model
6.2 Validation of Process Models
6.3 Application of the Model
6.4 Morphological Acceleration Techniques
6.5 Concluding Remarks
List of Symbols
List of Figures
Giles Lesser (Wellington, New Zealand, 1970) studied civil engineering at the University of Canterbury in Christchurch, New Zealand graduating in 1991. From 1992 until 1998 he worked as a civil engineer for Wellington City Council where, for a period, he was responsible for the maintenance of the city's many kilometres of coastal defences. In 2000 he was awarded an MSc on coastal engineering at UNESCO-IHE.
He was employed by Delft Hydraulics from 2001 until 2006. In February 2006 Giles relocated to Melbourne, Australia to finish his thesis.