1. Physical Stream Habitat

2. What is “Habitat”? Broad Definition (EPA): “The spatial structure of the environment which allows species to live, reproduce, feed and move” In Relation to Streams (USGS): “The physical and chemical characteristics of a stream that determine suitability for habitation and reproduction of stream organisms”

3. What is “Physical Habitat”? “The template of water depth, water velocity, substrate, cover and temperature that supports the stream ecosystem” – USGS

4. Stream Morphology Aquatic Community Physical Habitat Chemical Habitat Interspecies Interactions Land UseVegetation Hydrologic Conditions Geology Topography

5. Measurable Characteristics of Physical Habitat Channel morphology / type Flow regime Sediment texture / mobility Bank structural features / stability Riparian condition and connectivity Physiochemical – temperature, DO, metals, nutrients, turbidity, etc.

6. Mill Creek

7. Salmon and trout habitat requirements include: adequate but not excessive stream flows cool well-oxygenated unpolluted water streambed gravels that are relatively free of fine- sediments adequate food supply instream structural diversity (interposed pools, riffles, hiding and resting cover) Washington State Dept of Fish Wildlife

8. Physical stream characteristics affect stream organisms by defining: Habitat volume Habitat quality Disturbance magnitude Disturbance frequency

9. Habitat varies over spatial & temporal scales Stream Corridor Restoration, 199x

10. Scalar UnitDefinition Role in Habitat Characterization Watershed Basin Area defined by topography that contributes water and sediment to the stream network Determines boundary conditions within which river operates Segment Physiographically defined unit, based on relief, morphology and landscape position Determines boundary conditions within which river operates Reach Type Length of channel with uniform constraints resulting in a specific assemblage of geomorphic units Describes channel planform and geometry Geomorphic Unit Fluvial channel forms representing distinct form-process associations Determines channel character and behavior Habitat Type Patches of relatively uniform flow and substrate characteristics Describes ecologically relevant hydraulic and substrate conditions Large Scale Fine Scale Heirarchical Classification System

11. 10 3 m 10 2 m 10 1 m10 0 m 10 -1 m Watershed Segment Reach Type Geomorphic Unit Microhabitat Type How is each scale important to the species of interest?

12. Temporal Variability incorporates ‘predictable’ and ‘unpredictable’ cycles Macroinverts Salmon

13. Physical habitat a function of processes operating at multiple spatial and temporal scales How do we objectively assess it?

14. Define Stream Habitat Types (Classification) Bisson et al, 1982 McCain et al, 1990 (USFS) Hawkins et al, 1993 (USFS) Thomson et al, 2001 (UK, AUS) Fish - Centric

16. McCain et al, 1990

17. Bisson et al, 1982

18. Hawkins et al, 1993

20. McCain et al, 1990

21. Hydraulic Habitat Flow types can be distinguished by velocity and depth using Froude Number F = v gd

22. Panfil & Jacobson, 2000

23. Thomson et al, 2001

24. Stream Habitat types are created and maintained by erosion and deposition of sediments. Hjulstrom’s Diagram

25. Mechanics of Habitat Formation Shear Stress/Velocity Reversal Hypothesis Helical Flow Contraction/Expansion of Flow

26. t = rghs v ~ f(Rs) Knighton, 1998

27. Helical flow in meander bends Knighton, 1998

28. Flow contraction and expansion Wohl, 1998

29. Increased roughness reduces shear, promoting deposition of finer material McBain & Trush, 2004

30. Diversity is a function of fluctuations in erosion and deposition processes over varying scales What promotes Habitat Diversity? Disturbance

31. Natural flow regime Varying sediment inputs Structural diversity - LWD Natural stream systems are subject to the full spectrum of spatial & temporal disturbances Episodic Sediment Transport

32. Natural Flow Regime 5 characteristics :  Frequency  Magnitude  Duration  Timing  Rate of Change Key factor = extremes included

33. Disturbance acts to ‘reset’ processes Mount, 1995

34. Large Woody Debris Increases local scour and deposition Provides structural habitat Transient nature (moves, breaks, clumps, decays) All add to habitat diversity and complexity

35. Buffington & Montgomery 1999 Plane Bed Wood-poor Pool-riffle

36. Buffington & Montgomery 1999 Wood-rich Pool-riffle

37. Stream habitat diversity maintained over time  Species adapt Salmon – spawning and run timing Foothill Yellow-legged Frog – oviposition timing Cottonwood regeneration – accidental forest

38. Redrawn by Bledsoe from Schlosser (1995) Diversity in Trout Habitat

39. Alterations to flow regime & sediment supply alter habitat diversity & biodiversity Stream Corridor Restoration, 1998

40. Alterations to Stream Systems Flow extraction –diversions –groundwater withdrawal Flow augmentation –ag runoff –hydropower Sedimentation –development –logging –mining Sediment Loss –dams –mining

41. Channel Bed Coarsening Loss of Fines/Gravels Vegetation Encroachment Low bed mobility Degradation Channel Bed Fining Excess Fines/Gravels Lack of vegetation High bed mobility Aggradation

42. Effect of Dams Block Sediment “Flatline” Hydrograph Disrupt Connectivity Channel Degradation – bed coarsening, loss of fines/gravels Loss of extreme flows (loss of disturbance) – low bed mobility, vegetation encroachment, low habitat diversity Block habitat access, alter water chemistry, shift from lentic to lotic system

43. What can we do to improve spawning habitat conditions downstream of dams?