Numerical modelling

Tonkin + Taylor is New Zealand’s leading Environmental and Engineering Consultancy with over 40 years’ experience specialising in environmental, civil, structural, geotechnical and water resources engineering. These skills have been combined to develop a strong expertise in all facets of coastal and marine engineering, planning and science.

Numerical modelling is a powerful tool for investigating coastal processes and a temporal and spatial scale that cannot be done using field measurements or physical models. This enables us to simulate design events under higher sea level and extreme conditions, using field data or physical models for model calibration and validation. We offer a range of numerical modelling services requisite to get a better understanding of coastal processes, wave climate, hydrodynamics water levels, water quality and other coastal-related challenges. Numerical modelling is often undertaken in conjunction with field measurements or physical modelling to provide calibration confidence for application in the design of coastal structures or to understand future environmental change.

Areas of expertise:

  • Wave climate and harbour penetration modelling
  • Modelling of surf zone processes
  • Hydrodynamic modelling of coastal and estuarine processes
  • Water quality modelling
  • Sediment transport and morphological response modelling
  • Tsunami and pedestrian evacuation modelling
  • Wave run-up and coastal flood modelling
  • Vessel wake generation and propagation

Recent projects:

Ōpōtiki Harbour training wall design

A combination of models were used to inform Detailed Design of the Opotiki Harbour training walls. This includes preliminary modelling with SWAN to understand spectral wave transformation in the nearshore. To resolve complexities of reflection and convergence around the structures, a fully non-linear Boussinesq model Funwave-TVD was then used to inform sizing of armour units. Finally, the morphodynamic model XBeach and shoreline model Shoreline-S were used to investigate beach response to the design.

Majuro revetment design

XBeach non-hydrostatic was used to model across reef wave transformation and overtopping on an existing revetment that requires upgrading for sea level rise. The XBeach model resolves complex wave and surf-zone processes that are not easily captured in empirical formula and allows direct simulation of overtopping discharge and flooding.

Gravel beach overwash

When investigating coastal erosion hazards on gravel beaches in the Opotiki District, the numerical model XBeach - Gravel was used to simulate beach response to storm events at present day. This provided an output for the ‘dynamic zone’ where gravel can be mobilised during overwash events.

Vessel wake for feasibility design

Wake from regular maritime traffic can be the dominant source of energy in some inner harbour locations. Installation of a new pontoon in Hinemoa Reserve utilised a new nonlinear Boussinesq model to investigate how vessel wake can resonate in the local basin and become an important operational factor in design.

Tauranga Tsunami Inundation and Evacuation Modelling

Nearshore tsunami propagation (hydrodynamic) modelling and tsunami evacuation modelling to optimise evacuation times/routes for Tauranga City.

Waitangi Wharf Breakwater, Chatham Islands

Boussinesq wave transformation modelling to simulate the propagation of directional wave trains travelling from deep water to shallow water in the vicinity of the proposed wharf.

Vanuatu Inter-Island Shipping Support Project, Port Vila, Vanuatu

Hydrodynamic, wave, sediment transport and water quality modelling to assess effects of dredging a navigation channel north of South Paray wharf.

Lower Whanganui River updated numerical models

Hydrodynamic and wave modelling for the lower Whanganui River to assess waves (height, direction etc.) that penetrate the harbour.