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An active region model for capturing fractal flow patterns in unsaturated soils: model development
H H Liu1, R Zhang, G S Bodvarsson
1Earth Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA. hhliu@lbl.gov
Journal of Contaminant Hydrology
|August 16, 2005
Summary
Preferential flow in unsaturated soils can contaminate groundwater. This study introduces a fractal active region model to better predict this rapid solute movement, improving groundwater protection strategies.
Area of Science:
- Environmental Science
- Soil Science
- Hydrology
Background:
- Preferential flow in unsaturated soils facilitates rapid solute transport to groundwater.
- This bypasses soil volumes, increasing contamination risks.
- Observed field patterns suggest fractal characteristics.
Purpose of the Study:
- To develop a model incorporating fractal flow patterns into the continuum approach.
- To address the limitations of traditional models in predicting preferential flow.
- To enhance understanding of solute transport in heterogeneous soil environments.
Main Methods:
- Developed a simple active region model dividing the flow domain into active (fractal) and inactive regions.
- Derived a new constitutive relationship linking the active region portion to soil saturation.
- Integrated fractal geometry into a continuum-based soil flow model.
Main Results:
- The model successfully incorporates fractal flow patterns into the continuum approach.
- A novel constitutive relationship for the active region was established.
- Model predictions showed consistency with field observations of fractal flow.
Conclusions:
- The active region model provides a more accurate representation of preferential flow.
- Fractal geometry is key to understanding and modeling rapid solute transport.
- The model enhances the prediction of groundwater contamination risk from soil surface inputs.