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River Restoration Toolbox: Field Methods & Data Collection Overview

Learn basic field methods in river restoration - from site mapping to assessing pebble counts and sediment samples. Discover key techniques to determine bankfull elevation and discharge, essential for effective restoration projects.

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River Restoration Toolbox: Field Methods & Data Collection Overview

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  1. Module # 6Field Methods to Determine/ Verify Bankfull Elevation, XS Area & Discharge Iowa’s River Restoration Toolbox Level 1 / Base Training

  2. Overview of Basic Field Data Collection • Site Map • Cross Sections • Longitudinal Profile • Sediment Samples • Reach Ave Pebble Count • Riffle Armor Pebble Count • Bar Sample • Stream Assessment Harrelson, C.C., Rawlins, C.L., and Potyondy, J.P. Stream Channel Reference Sites: An Illustrated Guide to Field Technique: General Technical Report RM-245, Fort Collins, CO: U.S. Department of Agriculture - Forest Service, Rocky Mountain Forest and Range Experiment Station, 1994.

  3. Site Map • General Info • Legend • Photo Points • Terraces • Features • Pool/Riffle Sequences • Gravel & Sand Bars • Abandoned Channels • Measurements

  4. Buffalo Run, KY courtesy Stantec Bankfull Discharge • Controls Average, Long-Term Channel Form • Corresponds to the Discharge that Channel Maintenance is Most Effective over the Long-Term • Low Recurrence Interval • Lower Recurrence Interval in Urban Watersheds flow bkf time

  5. Bankfull Indicators • Flat, Depositional Surface Adjacent to Active Channel • Height of Depositional Features (Point Bars) • Change in Vegetation • Slope or Topographic Breaks or Changes Along the Bank • Check Versus Water Level

  6. Survey Equipment

  7. Cross Section Measurements Source: DL Rosgen

  8. Cross Section Measurements

  9. Cross Section Measurements • Bankfull Call/Elevation • Inner Berm Features • Floodprone Width • Bankfull Area • Bankfull Width and Depth

  10. Profile Survey • Thalweg • Water Surface • Define Facets • Bankfull Indicators • Lowest Bank • Terraces, Etc.

  11. Measuring Water Depths • Height of Rod @ Thalweg Location • Hold Rod at Water Surface • Move to River’s Edge

  12. Profile Survey • Bankfull Slope • Facet Slopes – Always Measure Water Surface • Pool to Pool Spacing • Pool Lengths • Facet Maximum Depths – Channel Bottom to Bankfull Elevation • Low Bank Height or Valley Bottom

  13. Particle Size Distributions • Field Measurements of Channel Materials • Reach Average (classification) • Riffle Bed (armor layer) • Depositional (bedload transport) • Estimate Distributions • Used to Estimate Bed Roughness

  14. Pebble Counts & Bar Samples 3. Obtain Sieve Analysis at the location of the largest particle on lower 1/3 of point bar or other depositional feature 1. Obtain a 100-particle pebble count on 10 transects from bankfull to bankfull throughout the reach (Classification) 2. Obtain a 100-particle pebble count in the riffle bed (Sediment Transport)

  15. Wolman Pebble Counts

  16. Wolman Pebble Counts

  17. Wolman Pebble Counts

  18. Particle Size Distributions

  19. Planform Geometry Measurements Wbkf = Bankfull Width Wblt = Belt Width Am = Amplitude Lm = Meander Wavelength Rc = Radius of Curvature

  20. Channel Length/Valley Length -or- Valley Slope/Channel Slope Sinuosity

  21. Design Reach Data Collection • Dependant Upon Purpose of Project • Impacted Reach (Minimum Data per Stream Type) • Planform Measurements • Riffle Cross Section • Reach Average Pebble Count • Riffle Bed Material Pebble Count • Bar Sample Sieve Analysis • Longitudinal Profile

  22. Additional Design Reach Data Collection • Site Constraints • Upstream and Downstream Tie-In • Tributaries • Valley Type and Slope • Available Material Onsite • Potential Restoration Methods

  23. Reference Reach Criteria • Stable Reference Stream in Same Hydro-Physiographic Region • Same Stream Type as Intended Design • Stable for Two Meander Wavelengths (20 Bankfull Widths) • Best if Similar Valley Slope and Sediment Regime as Impacted/Design Reach

  24. Reference Reach Data Collection • Planform Measurements • Facet Cross Sections (Riffle, Run, Pool & Glide) • Longitudinal Profile through 2 Meander Wavelengths (Minimum) or 20 to 30 Bankfull Widths • Reach Average Pebble Count • Riffle Bed Material Pebble Count • Bar Sample Sieve Analysis • Pfankuch Channel Stability Assessment • Site Controls (Bedrock, Wood)

  25. Module # 6Field Methods to Determine/ Verify Bankfull Elevation, XS Area & Discharge Iowa’s River Restoration Toolbox Level 1 / Base Training

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