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National Sedimentation Laboratory

National Sedimentation Laboratory. Regional/National Sediment Yields: Application of Fundamental Fluvial Geomorphic Techniques for TMDLs. Andrew Simon USDA-ARS National Sedimentation Laboratory. National Sedimentation Laboratory. Impairment to Designated Uses by “Clean Sediment”.

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National Sedimentation Laboratory

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  1. National Sedimentation Laboratory Regional/National Sediment Yields: Application of Fundamental Fluvial Geomorphic Techniques for TMDLs Andrew Simon USDA-ARS National Sedimentation Laboratory

  2. National Sedimentation Laboratory Impairment to Designated Uses by “Clean Sediment” How does “clean” sediment impair waterbodies?? • Suspended Sediment • High concentrations over specified durations • Potentially lethal/sub-lethal to organisms • Bed-material • High rates of bed-material transport over specified durations (unstable bed) • Loss of habitat for benthic macro-inverterbrates • Deposition of fines • Ditto

  3. National Sedimentation Laboratory Some Definitions • Shear stress: Force applied by flowing water on the surface of the stream bed (function of flow depth and slope) • Transport Capacity: Maximum amount of sand-sized and larger sediment a stream can carry at a given discharge or shear stress • Sediment Availability/Supply: Amount of sediment supplied from all upstream sources • Sediment Load: Mass or volume of sediment transported per unit of time • Sediment Yield: Mass or volume of sediment transported per unit of time and drainage area.

  4. National Sedimentation Laboratory Fundamental Mechanism Streams are open systems with an ability to adjust QS a Qsd50 Q = water discharge S = bed or energy slope Qs = bed-material discharge d50= median particle size of bed material

  5. National Sedimentation Laboratory A Rapid Means of Evaluating Thousands of Streams is Needed The very popular Rosgen Classification offers one such means of rapidly classifying streams • easy to understand • novices can perform • excellent communication tool about channel form We don’t have the time or the money to perform detailed analyses at every site that needs to be evaluated and that may require a TMDL Still, a scientifically defensible procedure is required

  6. National Sedimentation Laboratory Process, Process, Process Use Form to Tell Us About Process • Channel Evolution Models Use Form to Infer Process • Schumm et al., 1984 • Simon and the Hupp, 1986; Simon, 1989

  7. National Sedimentation Laboratory Stages of Channel Evolution(just another empirical model) • References • Stage I • Stage VI

  8. Stage and Fish-Community Structure

  9. Clean Sediment TMDLs:Geomorphic Link • Develop methodology to evaluate “reference” and disturbed conditions • Disturbed channels transport greater volumes of sediment for a given discharge • Rates of bed material and suspended-sediment transport vary by stage of channel evolution

  10. National Sedimentation Laboratory Level III Ecoregions and Available Data

  11. National Sedimentation Laboratory Field Work Locations (as of April 2010)

  12. National Sedimentation Laboratory Effective and Bankfull Discharge • Effective discharge is that discharge or range of discharges that transports the largest portion of the annual sediment load over the long term (Leopold and Wolman, 1960; Wolman and Miller, 1960; Andrews, 1980). • Generally accepted to be the bankfull discharge. • Annual-maximum series (1.5 years) or Partial-duration series (1.0 years)?? • Simon et al., 2004 verified this for numerous ecoregions

  13. National Sedimentation Laboratory Definition Sketch of Effective Discharge

  14. National Sedimentation Laboratory Two-Stage Suspended-Sediment Ratings 110,000 T/D 26,000 T/D

  15. National Sedimentation Laboratory Three-Stage Suspended-Sediment Ratings 12,000 T/D 4,900 T/D

  16. National Sedimentation Laboratory Nationwide Median Q1.5 Concentrations

  17. National Sedimentation Laboratory Nationwide Median Q1.5 Yields Highest in continental United States AZ/NM Plateau

  18. National Sedimentation Laboratory Q1.5 Sediment Yields: Hawaii

  19. National Sedimentation Laboratory Median Suspended-Sediment Concentrations

  20. National Sedimentation Laboratory Median Suspended-Sediment Yields

  21. EPA Region VIII

  22. Suspended-Sediment Transport

  23. An Example: Ecoregion 17

  24. National Sedimentation Laboratory Stages of Channel Evolution(to identify processes) • References • Stage I • Stage VI

  25. “Reference” Yields

  26. Mean Annual Yields

  27. Mean-Annual Reference

  28. Refined “Reference” by Bed-Material Size Class Ecoregion 65

  29. Comparing Reference to Actual Yields How much reduction is required?

  30. National Sedimentation Laboratory Preliminary Reference Yields

  31. National Sedimentation Laboratory Frequency of Given ConcentrationsWhat are thresholds for aquatic health?

  32. National Sedimentation Laboratory Durations of Given ConcentrationsWhat are thresholds for aquatic health?

  33. National Sedimentation Laboratory Duration of High Concentrations and Benthic Populations

  34. National Sedimentation Laboratory Frequency of Bed-Material Movement More unstable site (degraded)

  35. National Sedimentation Laboratory Frequency and Duration Metrics Frequency Duration

  36. Metrics for Stable and Unstable Sites Frequency Duration

  37. National Sedimentation Laboratory “Reference” Frequency of Exceedance (%) Highly erodable and disturbed loess area Lowland coastal areas Mtns. Plains

  38. National Sedimentation Laboratory “Reference” Frequency of Exceedance (Days) Highly erodable and disturbed loess area Lowland coastal areas

  39. National Sedimentation Laboratory “Reference” Durations Highly erodible and disturbed loess area Lowland coastal areas

  40. Developing a “Reference” Bed-Material Composition for the Ridge and Valley and Shades Creek • A reference bed-material composition is based on a measure of embeddedness; • The percentage of materials finer than 2 mm (sand, silt and clay) in gravel or gravel/cobble-dominated streambeds; • Applies to 53 of the sites evaluated along Shades Creek and 34 sites in the Ridge and Valley.

  41. Ridge and Valley Shades Creek Developing a “Reference” Bed-Material Composition • Median for both the Ridge and Valley and Shades is 4% • Consider the 75th percentile

  42. Comparison of Embeddedness Values for the Ridge and Valley and Shades Creek

  43. Application to San Juan River Basin

  44. Stage of Channel Evolution

  45. National Sedimentation Laboratory Ecoregion 22 Bed-Material Reference Inter-quartile range: 0 – 20%

  46. National Sedimentation Laboratory San Juan River Basin Reference Inter-quartile range: 12 – 30%

  47. National Sedimentation Laboratory Animas River

  48. National Sedimentation Laboratory Bed-Material Conditions for Study Reaches

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