Tuflow and estry manual Version 3

• 
  Calibration to recorded information (if available).
  
• 
  Crosschecked using desktop calculations based on theory and/or standard publications (eg. Hydraulics of Bridge Waterways).
  
• 
  Crosschecked with results using other hydraulic software (eg. HEC-RAS).
  

It is important to note that contraction and expansion losses associated with structures are modelled very differently in 1D and 2D schemes. 1D schemes rely on applying form loss coefficients, as they cannot simulate the horizontal or vertical changes in velocity direction and speed. 2D schemes model these horizontal changes and, therefore, do not require the introduction of form losses to the same extent as that required for 1D schemes. However, 2D schemes do not model losses in the vertical or fine-scale horizontal effects (such as around a bridge pier) and, therefore, may require the introduction of additional form losses. See Syme 2001b for further details.