1. Predicting natural channel types in the Columbia River basin Hiroo Imaki 1, Tim Beechie 1, John Buffington 2 1. NOAA, Northwest Fisheries Science Center, 2. USFS, Rocky Mountain Research Station 2010.10.28

2. Questions

3. Columbia River Basin Historical Ecology Project Channel Type Riparian Vegetation Salmon Distribution Salmon Distribution

4. Project Objectives Establish a guideline to restore stream processes for endangered salmon and biodiversity Our methods and products can be used as… – Natural channel type template for restoration – Restoration prioritization tool

5. Columbia River Basin Area 668,000km 2 Total stream length 444,121 km Columbia River Basin Area 668,000km 2 Total stream length 444,121 km Our common perspective

6. Why Channel Types?

7. Floodplain Channel Types StraightMeanderingBraidedIsland-braided Beechie et al. (2006)

8. Mountain Channel Types Montgomery and Buffington (1997) Cascade Step-pool Plane-bed Pool-riffle

9. Channel Type System Pool-riffle Step-pool Plane-bed Cascade Slope < 0.015 Slope < 0.03 Slope < 0.065 BFW< 8 m * Meandering Island-braided Braided Straight Reach Prediction Model * Mountain ChannelsFloodplain Channels Yes No Montgomery and Buffington (1997) * Hall et al. (2007) Confined Beechie and Imaki (in review) * Support Vector Machine

10. Biophysical Floodplain Channel Type Model

11. Methods Establish channel type reference reaches Calculate geomorphic characteristics GIS data preparation (DEM, stream, etc.) Build a model and predict channel types (Support Vector Machine) Field measurements 1.Slope 2.Bankfull width 3.Floodplain width 4.Relative shear stress (RSS) 5.Fine sediment supply Fine sediment Alpine sediment 6.Root strength / Wood supply ABC Flow direction Profile Reach RSS + - Relative shear stress

13. N 0 50 km

14. Prediction accuracy and error Observed channel type Predicted channel type Braided Island- braided MeanderingStraightTotalAccuracy Braided 204012580% Island-braided 118442767% Meandering 122222781% Straight 420192576% Total 26 104 Accuracy 77%69%85%73% Channel type ~ Slope + acc_precip + r_stress + fine_sediment + alpine_sediment Overall accuracy = 76% Kappa = 0.69

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