7. The Clean Water Course Swale Water Quality Treatment Stream Restoration Projects Watersheds 2000 Healthy Streams Plan Watershed Based Permit Stream Erodibility Study Vegetated Corridor Standards
21. What does flow have to do with it? (USEPA - after Wolman and Miller 1960)
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26. Obtained from jet-test device = k ( o - c ) = erosion rate (m/s) k = erodibility coefficient (m 3 /N-s) o = boundary shear stress (Pa) c = critical shear stress (Pa) ( o - c ) = excess shear stress Critical shear stress is the stress required to initiate erosion. The Equation
27. Jest Test Device Jet Nozzle Jet Nozzle As scour hole depth increases, shear stress decreases
28. From Relation between Shear Stress and Erosion We Can Calculate c and Shear Stress, Pa Erosion Rate, cm 3 /sec c
36. Cohesive Strength Meter (CSM ) The CSM consists of a water-filled chamber 30 mm in diameter that is pushed into the sediment. The jet of water comes from a downward directed nozzle in the chamber. The velocity of the jet is increased systematically through each experiment. Bed erosion is inferred from the drop in the transmission of infrared light across the chamber caused by the suspension of sediment. Lighter, Faster, not as robust, indirect measurement