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Bed-material Sampling. May 2013 TESNAR Class Mackenzie Keith Hydrologist Oregon Water Science Center Portland, Oregon. The b-axis. From Bunte and Abt, 2001. Why measure bed material?. Sediment transport calculations and indications Fish/habitat /bio studies - PowerPoint PPT Presentation
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U.S. Department of the InteriorU.S. Geological Survey
Bed-material Sampling
May 2013 TESNAR Class
Mackenzie KeithHydrologistOregon Water Science CenterPortland, Oregon
Why measure bed material?
Sediment transport calculations and indications
Fish/habitat /bio studies Balance between supply and transport Sediment attrition Lithology
What’s in a D50? Plotting and reading data Bed material can range over several orders of
magnitude Log transformations and the phi scale Reading and reporting D50 (or D16, D84, or
whatever) Looking at multiple sets of data
Techniques for coarse material sampling: The grains
Operator bias Which side is the b-axis? Results from yesterday How many clasts do I count? What if I can’t pick the clast up? Surface Subsurface
Techniques for coarse material surface sampling: The counts Facies mapping Wolman pebble counts Sampling frames Ocular assessments Photogrammetric techniques Zig-Zag Bank to bank Other aquatic habitat measures
Techniques for coarse material surface sampling: Longitudinal Choosing the right location Choosing the right spacing Choosing the right grain Tiny clasts? Giant clasts?
A method for subsurface sampling: Bulk sampling Clearing the surface layer Digging, sieving, and weighing How much to dig up? Filling in the hole