1 / 26

Module # 6 Field Methods to Determine/ Verify Bankfull Elevation, XS Area & Discharge

Module # 6 Field Methods to Determine/ Verify Bankfull Elevation, XS Area & Discharge. Iowa’s River Restoration Toolbox Level 1 / Base Training. Overview of Basic Field Data Collection. Site Map Cross Sections Longitudinal Profile Sediment Samples Reach Ave Pebble Count

lylee
Download Presentation

Module # 6 Field Methods to Determine/ Verify Bankfull Elevation, XS Area & Discharge

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  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

More Related