Aquatic Habitat Conditions in the Lower Snoqualmie, Tolt, and Raging Rivers September 2018 Alternate Formats Available Aquatic Habitat Conditions in the Lower Snoqualmie, Tolt, and Raging Rivers Prepared for: Snoqualmie Watershed Forum Submitted by: Josh Kubo King County Water and Land Resources Division Department of Natural Resources and Parks Funded in part by: Snoqualmie Watershed Forum Cooperative Watershed Management Grant Program Aquatic Habitat Conditions in the Lower Snoqualmie, Tolt, and Raging Rivers Acknowledgements First and foremost, the authors would like to thank the Snoqualmie Watershed Forum for funding and supporting this project. Special thanks goes out to Matt Baerwalde, Angela Dillon, and Heather Minnella at the Snoqualmie Tribe for providing input on project design and for thoroughly supporting data collection and field surveys. Without the dedicated and generous support from staff at the Snoqualmie Tribe, this project would not have been possible. The authors would also like to thank Chris Gregersen, Dan Lantz, Elissa Ostergaard, and Jo Wilhelm for field surveys, Ken Rauscher for GIS support, Brian Footen for FishViews coordination and use, Chris Gregersen for the FishViews desktop evaluation, as well as Matt Baerwalde, Josh Baldi, Kollin Higgins, Beth leDoux, Kate O’Laughlin, Elissa Ostergaard, Mike Rustay, Michael Thai, Colin Wahl, Dave White, and Jo Wilhelm for thorough comments on previous drafts of the report. Citation King County. 2018. Aquatic Habitat Conditions in the Lower Snoqualmie, Tolt, and Raging Rivers. Prepared by Josh Kubo, Water and Land Resources Division. Seattle, Washington. King County Science and Technical Support Section i September 2018 Aquatic Habitat Conditions in the Lower Snoqualmie, Tolt, and Raging Rivers Table of Contents Executive Summary............................................................................................................................................ vii 1.0 Introduction .............................................................................................................................................. 1 2.0 Methods ...................................................................................................................................................... 4 2.1 Field Survey Area and Methods .................................................................................................... 4 2.2 Selected Field Survey Metrics ....................................................................................................... 6 2.2.1 Bank Conditions............................................................................................................................ 7 2.2.2 Large Woody Debris and Jams ................................................................................................ 8 2.2.3 Instream Habitats and Floodplain Features ...................................................................... 9 2.2.4 Channel and Floodplain Modifications ..............................................................................10 2.3 Riparian Conditions ........................................................................................................................10 2.4 Habitat Conditions Comparisons ...............................................................................................10 2.5 Riparian Change Analysis .............................................................................................................11 2.6 FishViews Comparison ..................................................................................................................12 3.0 Results and Discussion .......................................................................................................................13 3.1 Bank Conditions ...............................................................................................................................13 3.2 Large Woody Debris and Jams ....................................................................................................19 3.3 Instream Habitat and Floodplain Features ............................................................................25 3.4 Channel and Floodplain Modifications ....................................................................................31 3.5 Riparian Conditions and Land Cover Change Analysis .....................................................36 3.6 FishViews Desktop Evaluation ...................................................................................................56 4.0 Conclusions .............................................................................................................................................61 5.0 References ...............................................................................................................................................65 Figures Figure 1. 2017 habitat conditions survey extent (white halo) and EDT Reaches (colored segments) among the lower Snoqualmie, Tolt, and Raging, rivers. ....... 5 Figure 2. 2000/2001 and 2017 modified bank conditions organized by EDT reach across the Snoqualmie and Tolt rivers. .............................................................................16 Figure 3. Locations of significant changes in bank condition across the lower Snoqualmie, Tolt, and Raging rivers. ..................................................................................17 King County Science and Technical Support Section ii September 2018 Aquatic Habitat Conditions in the Lower Snoqualmie, Tolt, and Raging Rivers Figure 4. Proportions of instream glide, pool, and riffle habitats in the lower Snoqualmie, Tolt, and Raging rivers. ..................................................................................26 Figure 5. Water irrigation pumps observed in the lower Snoqualmie River from RM 10 to RM 19 in 2017 as well as previously in 2000/2001. ........................................34 Figure 6. Water irrigation pumps observed in the lower Snoqualmie River from RM 23 to RM 31 in 2017 as well as previously in 2000/2001. ........................................35 Figure 7. Areas of channel migration in the mainstem Snoqualmie River observed from aerial imagery analysis between 2002 and 2015. ..............................................39 Figure 8. Select changes in riparian land cover around RM 21 on the mainstem of the lower Snoqualmie River from 2002 to 2015. ..................................................................41 Figure 9. Select changes in riparian land cover around RM 11 on the mainstem of the lower Snoqualmie River from 2002 to 2015. ..................................................................43 Figure 10. Areas of channel migration in the lower Tolt River observed from aerial imagery analysis between 2002 and 2015. .....................................................................45 Figure 11. Select changes in riparian land cover around RM 2.5 on the mainstem of the lower Tolt River from 2002 to 2015. .................................................................................47 Figure 12. Select changes in riparian land cover around RM 0.5 on the mainstem of the lower Tolt River from 2002 to 2015. .................................................................................49 Figure 13. Areas of channel migration in the Raging River observed from aerial imagery analysis between 2002 and 2015. .....................................................................51 Figure 14. Select changes in riparian land cover around RM 4 on the mainstem of the lower Raging River from 2002 to 2015. ............................................................................53 Figure 15. Select changes in riparian land cover around RM 4.5 on the mainstem of the lower Raging River from 2002 to 2015. ............................................................................55 Tables EDT Reach details for the lower Snoqualmie, Tolt, and Raging rivers .................... 6 Aquatic habitat condition metrics for large river systems. ......................................... 7 2017 Snoqualmie, Tolt, and Raging rivers bank conditions organized by EDT reach. .....................................................................................................................................14 2000/2001 and 2017 bank conditions across the Snoqualmie, Tolt, and Raging rivers. ...............................................................................................................................15 2000/2001 and 2017 bank conditions organized by EDT reach across the Snoqualmie, Tolt, and Raging rivers. ..................................................................................15 Large woody debris observed in the lower mainstem Snoqualmie River ...........19 Large woody debris observed in the Tolt River .............................................................20 King County Science and Technical Support Section iii September 2018 Aquatic Habitat Conditions in the Lower Snoqualmie, Tolt, and Raging Rivers Large woody debris observed in the Raging River .......................................................21 Large woody debris conditions observed in 2017 and 2000/2001 as well as comparison to condition standards outlined by the National Marine Fisheries Services (NMFS 1996) and by Fox and Bolton (2007). ...........................24 Instream habitats observed in the lower mainstem Snoqualmie River. ..............27 Instream habitats observed in the Tolt River. ................................................................27