1. Stream Classification

2. What factors affect stream morphology? Width Depth Slope Velocity Discharge Flow resistance Sediment size Sediment load Leopold et al (1964)

7. Why classify?

8. Communication Tool Describe Existing Conditions & Trends Describe Restoration Goals Stream Classification Research Tool

9. Classification Schemes Wolman, Leopold and Miller/Schumm Method Montgomery and Buffington Method Rosgen Method

10. Leopold and Wolman/Schumm Classification

11. Wolman and Miller/Schumm Classification Channel Patterns (alluvial) ….in plan view (bird’s eye) Straight Meandering Braided Transition between Straight And Meandering is when Sinuosity is 1.5

12. (pools and riffles) Riffles are spaced ~ 5-7 times the channel width

13. Montgomery and Buffington Method

14. “Process-Based Approach” Montgomery and Buffington Method

15. Process-Based Approach Streams classified the same not only look similar, they are formed by similar processes. Basic premise is that streams with similar form (and formative processes) will function similarly.

16. Montgomery and Buffington, 1997 hillslope channel head colluvial cascade step-pool plane-bed pool-riffle dune-ripple High Transport Capacity Depositional Reaches

17. ‘Colluvial’ vs. ‘Alluvial’ Colluvial: unorganized and poorly sorted deposits at the base of a hillslope, formed by gravity. Alluvial: formed by the action of flowing water, indicated by rounded rocks, distinct channel banks, and organized bed forms.

18. Colluvial Channel

19. Why are colluvial channels important for alluvial river ecosystems?

20. Comprise >80% of the channel network Major pathway for the routing of water, sediment, organic matter, and thermal energy to downstream areas Unique and/or predator-free habitats for numerous amphibians and invertebrates

21. Process Domains Channel Head Colluvial Channels 1. Earth Flows 2. Gully Erosion 3. Debris Flows Fluvial Channel Network C C C C

22. 1.) Earth Flow Terrain

23. Copyright © Martin Geertsema 2002

24. 2.) Gully Erosion

25. 3.) Debris Flow Terrain

29. Montgomery and Buffington, 1997 hillslope channel head colluvial cascade step-pool plane-bed pool-riffle dune-ripple High Transport Capacity Depositional Reaches

30. Cascades High Gradient, Confined Channels

31. Cascades High Gradient, Confined Channels Poorly organized cobble and boulder bed Tumbling flow over large, protruding grains gradient ≥ 7%

32. Step-Pool High Gradient, Confined Channels

33. Step-Pool High Gradient, Confined Channels Interlocking cobbles and boulders organize into discrete channel- spanning stone lines that form alternating drops (steps) and pools. Gradient: 4 - 6%

34. Cascades Step-Pool High Gradient, Confined Channels Are they very responsive to change?

35. Montgomery and Buffington, 1997 hillslope channel head colluvial cascade step-pool plane-bed pool-riffle dune-ripple High Transport Capacity Depositional Reaches

36. Plane Bed Pool Riffle Moderate to Low Gradient, Unconfined Channels

37. Plane BedPool Riffle Moderate to Low Gradient, Unconfined Channels Are they sensitive to changes in sediment & wood supply and/or discharge? How / where do organisms seek refuge during floods?

38. Plane Bed Moderate to Low Gradient, Unconfined Channels

39. Plane Bed Moderate to Low Gradient, Unconfined Channels relatively featureless gravel / cobble bed streams homogeneous habitat 2 – 4% slope

40. Plane-Bed Channels

41. Pool Riffle Moderate to Low Gradient, Unconfined Channels

42. Pool Riffle Moderate to Low Gradient, Unconfined Channels Bedforms: alternating bar / pool Plan form: sinuous Gradient: < 2%

43. Copyright © Norm Catto 2002

45. Braided Streams

46. Dune Ripple Extremely Low Gradient, Unconfined Channels

49. Bedrock Channels

53. Why are there bedrock channels?

54. Sediment transport exceeds sediment supply Grain size of sediment is small relative to the transport capacity (channel slope * drainage area)

55. Montgomery and Buffington, 1997 hillslope channel head colluvial cascade step-pool plane-bed pool-riffle dune-ripple High Transport Capacity Depositional Reaches

56. Channel Gradient Particle Size Montgomery and Buffington, 1997 Valley Confinement hillslope channel head colluvial cascade step-pool plane-bed pool-riffle dune-ripple High Transport Capacity Depositional Reaches

58. Channel Type -- Colluvial channels (>10%) -- Cascade (7-10%) -- Step-Pool (3-7%) -- Plane-Bed (1.5-3%) -- Pool-Riffle (<1.5%)

59. Channel Types & Bed Mobility Cascade and Step Pool channels typically have an abundance of large, interlocking boulders that limit bed mobility. Benthic organisms can seek shelter in interstitial spaces. Plane Bed and Pool Riffle channels typically have mobile beds during large floods. Benthic organisms can seek shelter in less mobile areas of the channel. Dune Ripple channels are fully mobile during most storms. Benthic organisms may be limited to wood.

60. Rosgen Method

61. Link to Wildland Hydrology

62. Link to website:

63. Rosgen Classification of Natural Rivers Based on physical characteristics (empirical) Requires field measurements Requires bankfull dimensions

64. Solving for the eight variables… Width Depth Slope Velocity Discharge Flow resistance Sediment size Sediment load Leopold et al (1964)

65. Four Primary Components of the Rosgen Method Dimension (cross-section) Pattern (plan form) Profile (bed form) Bed material (substrate)

66. Level One: Rosgen Classification

67. Level Two: Rosgen Classification

79. Level One: Rosgen Classification

108. Strengths and Weaknesses of Rosgen Method…..

109. Stream Succession…..