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River Bank Erosion

River Bank Erosion. Siskiwit River, Cornucopia, WI. How Do we Measure Bank Erosion?. The Big Questions…continued. Are there simple methods that can be used to estimate bank erosion rates in the field?. Answer…No. Lateral Movement of bank. Measured in feet/year. Resisting Force

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River Bank Erosion

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  1. River Bank Erosion Siskiwit River, Cornucopia, WI

  2. How Do we Measure Bank Erosion?

  3. The Big Questions…continued • Are there simple methods that can be used to estimate bank erosion rates in the field? Answer…No

  4. Lateral Movement of bank. Measured in feet/year Resisting Force Intrinsic property of bank. Function of: Soil Vegetation Bank Angle Etc. Driving Force Property of the hydraulics. Function of: Near Bank Shear Stress Bank Erosion

  5. Bank Erodability How do we determine how susceptible a bank is to erosion?

  6. Predicting Bank Erosion Bank Erosion Hazard Index (BEHI)

  7. BEHI Variables • Bank Height Ratio • Root Depth Ratio • Weighted Root Density • Bank Angle • Surface Protection • Bank Material • Stratification

  8. Black River, Michigan (UP) Low Erosion Potential

  9. Moderate Erosion Potential Coldwater Creek, Union City, Michigan

  10. Very High / Extreme Erosion Potential Ontonagon River, Michigan (UP)

  11. Bank Erosion Near Bank Stress (NBS) Index Bank Erosion Hazard Index (BEHI)

  12. NBS#1 - Channel Patterns • Transverse and/or central bars – short and/or discontinous • NBS = High or Very High • Extensive deposition • NBS = Extreme • Chute cutoffs, down-valley meander migration, converging flow • NBS = Extreme

  13. NBS#2 – Ratio of Radius of Curvature (Rc) to Bankfull Width (Wbkf) Generally Rc Performed Using Aerial Photography

  14. NBS#3 & #4 – Ratio of Pool Slope to Average Slope (Sp/S) or Riffle Slope (Sp/Srif)

  15. NBS#5 – Pool Depth to Average Depth

  16. Measuring Bank Erosion

  17. Bank Erosion Bank Pins & Bank Profiles Bank Erosion Hazard Index (BEHI) Near Bank Stress (NBS) Index

  18. Bank Profile Measurement Equipment • Toe Pin (rebar) • Toe Pin Cap • Hammer • Survey Rod (2) or • Survey Rod & Pocket Rod • Line Level • Rod Level • Field Forms

  19. Measuring Bank Profile Source: Arkansas Department of Environmental Quality

  20. Comparison of Bank Profiles

  21. Bring it all Together Regional Curves

  22. Great Lakes Curves - Preliminary

  23. Is there a better correlation for predicting bank erosion? • Remotely-sensed data • Radius of curvature • Meander wavelength • Beltwidth:valley width • Valley slope • Soils maps for resistance and infiltration

  24. Questions? Contact: Dr. Jim Selegean, P.E., P.H. U.S. Army Corps of Engineers, Detroit District Great Lakes Hydraulics and Hydrology Office 477 Michigan Ave Detroit, MI 48226 313.226.6791 james.p.selegean@usace.army.mil

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