1. Processing of a Fine Sediment Pulse after Dam Removal Sediment Budget and Longitudinal Trends Chiloquin Dam Removal – Sprague River Matt Cox, Desiree Tullos, Cara Walter

2. Map: Mike Neumann, USBR Background: Chiloquin Dam

3. Objectives Develop a preliminary sediment budget for the Chiloquin Dam removal location from pre removal (2008) to 2 years post removal (2010) Examine longitudinal trends in the processing of the fine sediment pulse.

4. Topography/Bathymetry 2006,2007, 2008, 2009,2010 ADCP 2008,2009 and 2010 GPS RTK Ground Surveys Sediment riffles - pebble counts SSC collected by Klamath Tribes and USGS Turbidity, discharge, and stage USGS gage (#11501000) on the Sprague River USGS gage (#11502500) on the Williamson River Methods: Field Data Collection

5. Methods: Discharge, Turbidity, and SSC Sampling Upstream – USGS Gauge 11501000

6. Methods: Estimation of Suspended Sediment Concentration Turbidity vs. SSC at Sprague River near Chiloquin (US of reservoir) N = 66 samples T urbidity vs. SSC at Williamson River below Sprague River near Chiloquin (DS of reservoir) N = 48 samples

7. Methods: Reservoir erosion Repeat cross sections in 2008, 2009 and 2010 Volume change calculated from differences in reoccupied cross-sections

8. Methods: Surfacing and GCD uncertainty 1.Difference DEMs 2.Filter by uncertainty 3.Filter by spatial coherence 4.Extract cells of erosion and deposition Wheaton, J. M., Brasington, J., Darby, S. E. and Sear, D. A. (2010), Accounting for uncertainty in DEMs from repeat topographic surveys: improved sediment budgets. Earth Surface Processes and Landforms, 35: 136–156. doi: 10.1002/esp.1886 -

9. Results:Longitudinal trends in Sediment Deposition

10. D50 Upstream\D50 Downstream

11. Results: Reservoir Erosion

12. Results : Downstream SSC

13. Results: Suspended Sediment release during drawdown and removal

14. Results: Annual Suspended Sediment Load Yearly suspended sediment discharge (in metric tons) above and below the site of the Chiloquin Dam removal

15. Results: Downstream Differenced DEMs Sprague River Analysis Units

16. Results: Downstream Net Volume Change- Sprague River Analysis Units

17. Results: Downstream Differenced DEMs Williamson River Analysis Units

18. Results: Net Volume Change- Williamson River Analysis Units

19. Results: Sediment Volume deposited in Pool Analysis Units

20. Chiloquin Dam Removal Sediment Preliminary Sediment Budget 2008 - 2010 Upstream Boundary - SSC from turbidity Downstream Boundary - SSC from turbidity DS Deposition - DEM differencing Reservoir Erosion - Volume change from repeat XS surveys

21. Conclusions Sprague and Williamson Rivers are still processing the pulse of sediment input by the Chiloquin Dam Removal. Pool filling has been observed in both 2009 and 2010. Very little pool scour was observed. Basin wide trends may be partially obscuring the sediment signal of the removal. The suspended sediment signal from the drawdown event was very small compared to annual suspended sediment loads.

22. Future work – Links to Habitat data Reach scale habitat and invertebrate data (EPA EMAP protocol) collected in 2008, 2009 and 2010. Movement of endangered fish – USGS telemetry study ongoing.

23. Acknowledgements Dr. Desiree Tullos Cara Walter Summer Field Techs – Greg Woloveke, Kaileen Amish, Ryan Caruso, Adam Wyborny, Meredith Cavanaugh

24. Questions?