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

Impairment to Designated Uses by “Clean Sediment” 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 How does “clean” sediment impair waterbodies?? 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. National Sedimentation Laboratory

Fundamental Mechanism QS  Q s d 50 Q = water discharge S = bed or energy slope Q s = bed-material discharge d 50 = median particle size of bed material Streams are open systems with an ability to adjust National Sedimentation Laboratory

A Rapid Means of Evaluating Thousands of Streams is Needed National Sedimentation Laboratory 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 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

Process, Process, Process National Sedimentation Laboratory 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

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

Stage and Fish-Community Structure

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

Level III Ecoregions and Available Data National Sedimentation Laboratory

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

Definition Sketch of Effective Discharge National Sedimentation Laboratory

Two-Stage Suspended-Sediment Ratings 26,000 T/D 110,000 T/D

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

Nationwide Median Q 1.5 Concentrations National Sedimentation Laboratory

Nationwide Median Q 1.5 Yields National Sedimentation Laboratory Highest in continental United States AZ/NM Plateau

National Sedimentation Laboratory Q 1.5 Sediment Yields: Hawaii

National Sedimentation Laboratory Median Suspended-Sediment Concentrations

National Sedimentation Laboratory Median Suspended-Sediment Yields

EPA Region VIII

Suspended-Sediment Transport

An Example: Ecoregion 17

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

“Reference” Yields

Mean Annual Yields

Mean-Annual Reference

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

Comparing Reference to Actual Yields How much reduction is required?

National Sedimentation Laboratory Preliminary Reference Yields

Frequency of Given Concentrations What are thresholds for aquatic health? National Sedimentation Laboratory

Durations of Given Concentrations What are thresholds for aquatic health? National Sedimentation Laboratory

Duration of High Concentrations and Benthic Populations National Sedimentation Laboratory

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

National Sedimentation Laboratory Frequency and Duration Metrics Frequency Duration

Metrics for Stable and Unstable Sites FrequencyDuration

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

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

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

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.

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

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

Application to San Juan River Basin

Stage of Channel Evolution

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

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

Animas River National Sedimentation Laboratory

Bed-Material Conditions for Study Reaches National Sedimentation Laboratory