The accumulated bank erosion can be used for updating the bank lines, and for updating the curvilinear grid (extent of the modelling area) at every time-step. The bank erosion is computed from a formula relating near-bank conditions to bank erosion rates. Alluvial resistance due to bed material and bed forms.MIKE21C is particular suited for river morphological studies and includes modules to describe:. MIKE 21C is a special module of MIKE 21 based on a curvilinear (boundary-fitted) grid, which makes it suitable for detailed simulation of rivers and channels, where an accurate description of bank lines is required. Generally, for flood modelling, river bed and channel form are fixed (excepting the development of breaches). blockages) at structures, and to develop river maintenance schemes. introduction of culverts, flood defences, etc), morphological change is usually limited to the consideration of scour or silting (e.g. While it is commonplace to model the physical changes to a watercourse or flood plain as a result of urbanisation (e.g. However, the consideration of other factors may also be critical. The primary long term factor affecting river hydrodynamics, and flood risk, is climate change. An example of this would be if the development was controlled by a time limited planning condition.’ (PPS25 Practice Guide) For guidance, residential development should be considered for a minimum of 100 years, unless there is specific justification for considering a shorter period. ‘For practical reasons it is difficult to define the lifetime of development as each development will have different characteristics. minimum lifetime of a residential development from PPS25) has been used. For the purpose of this example, a design life of 100 years (i.e. In the UK, flood risk and where necessary mitigation must be considered throughout the design life of the development. A MIKE 21C Concept Demonstration: Is it Possible to Model the Impact on Flood Risk due to the Morphological and Planform Change of a River over the Lifetime of a Development?
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