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Evaluating Increased Erosion Potential due to Wildfires Brian Drake CE394K – Fall 2005 Term Project Presentation

Evaluating Increased Erosion Potential due to Wildfires

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Evaluating Increased Erosion Potential due to Wildfires. Brian Drake CE394K – Fall 2005 Term Project Presentation. Study Area. Cedar Wildfire. Duration: 10/25/03 – 11/3/03 Size = 280,000 acres 2,232 homes destroyed 15 human deaths Suppression Cost: >$31 Mil. - PowerPoint PPT Presentation

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Page 1: Evaluating Increased Erosion Potential due to Wildfires

Evaluating Increased Erosion Potential due to Wildfires

Brian DrakeCE394K – Fall 2005

Term Project Presentation

Page 2: Evaluating Increased Erosion Potential due to Wildfires

Study Area

Page 3: Evaluating Increased Erosion Potential due to Wildfires

Cedar Wildfire

• Duration: 10/25/03 – 11/3/03• Size = 280,000 acres• 2,232 homes destroyed• 15 human deaths• Suppression Cost: >$31 Mil

Page 4: Evaluating Increased Erosion Potential due to Wildfires

Major Factors Affecting Soil Losses

• Vegetative Cover• Soil Characteristics• Topography• Intensity of Storms

Page 5: Evaluating Increased Erosion Potential due to Wildfires

Modeling Erosion

• USDA Universal Soil Loss Equation (USLE)

• A = R∙K∙LS∙C∙P– A = Soil loss per unit area– R = Rainfall-Runoff Erosivity– K = Soil Erodibility– LS = Slope Length/Steepness Factor– C = Land Cover Factor– P = Conservation Practice Factor

Page 6: Evaluating Increased Erosion Potential due to Wildfires

Rainfall-Runoff Erosivity (R)

• Reflects rainfall intensity and storm energy

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Soil Erodibility (K)

• Represents susceptibility of soil to erosion

Legend0.100000002 - 0.136666669

0.136666669 - 0.173333336

0.173333336 - 0.210000003

0.210000003 - 0.246666671

0.246666671 - 0.283333338

0.283333338 - 0.320000005

0.320000005 - 0.356666673

0.356666673 - 0.393333340

0.393333340 - 0.430000007

Page 8: Evaluating Increased Erosion Potential due to Wildfires

Slope Length/Steepness (LS)

 

LS = (a/22.13)0.4 (s/0.0896)1.3

DEM

Page 9: Evaluating Increased Erosion Potential due to Wildfires

Land Cover Factor (C)• Ratio of soil loss based on vegetative cover

Page 10: Evaluating Increased Erosion Potential due to Wildfires

Conservation Practice Factor (P)

• Reflects impact of erosion-reduction practices

Page 11: Evaluating Increased Erosion Potential due to Wildfires

Total Sediment Potential (A)

Aave = 30.7 ton/acre/yr

Aave = 1,295 ton/acre/yr

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Remaining Tasks

• Adjustments to current pre-fire calculation– Check for unit consistency– Search for more representative R-Factor– Ensure that LS value is accurate

• Modify factors to model post-fire conditions– Increase C-Factor

Page 13: Evaluating Increased Erosion Potential due to Wildfires

Resources

• DEM: http://seamless.usgs.gov/

• NHD: http://nhd.usgs.gov/data.html

• USDA Soils: http://www.ncgc.nrcs.usda.gov/products/datasets/statsgo/

• Fire Info: http://map.sdsu.edu/fireweb/

Page 14: Evaluating Increased Erosion Potential due to Wildfires

Questions?