Erosion modeling for a small watershed

1. Digital elevation model and topographic parameters computed from point data by the RST method in GRASS5.0

1m resolution, 3x vertical exaggeration

• elevation
• slope
• aspect
• profile curvature
• tangential curvature
  

2. Erosion/deposition pattern predicted by models

Unit Stream Power Based Model (USPED): transport capacity limited erosion

• USPED, p=1
• USPED, p=1.6

Bivariate continuity equation based model SIMWE (diffusion coef is 0.1 (low) in all examples, critical sheer stress is negligible):

• n=0.05, p=1.5:
  • water depth
  • sediment flow
  • net erosion/deposition
    
  
  
• n=0.1, p=1.0, approximate dynamic
  
  • Animation representing the spatial distribution of overland water depth and net ersoion deposition for increasing time interval:
    animated gif
    mpeg movie
    

    snapshots from the animation :

  • net erosion/deposition: after 100 iterations, before steady state, there is only deposition in the valley center
    
  • net erosion/deposition: after 500 iterations, before steady state
    
  • net erosion/deposition: steady state, gully in the valley center develops with both high erosion and deposition rates
    
  • development of water flow
    
    
• n=0.1, p=0.6
  net erosion/deposition

3. Comparison with Cs data

see Application of TBGIS on a UK field

Computed with GRASS5.0

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