processing of a fine sediment pulse after dam removal sediment budget and longitudinal trends...

Processing of a Fine Sediment Pulse after Dam Removal

Sediment Budget and Longitudinal Trends

Chiloquin Dam Removal – Sprague RiverMatt Cox, Desiree Tullos, Cara Walter

Map: Mike Neumann, USBR

Background: Chiloquin Dam

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.

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 RiverUSGS gage (#11502500) on the Williamson River

Methods:Field Data Collection

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

Cara Walter

dam removal line to help orient with next slide?I'm wondering if this would be easier to read if the discharge data was upside down (similar to rainfall/discharge plots) - I think you accomplish this with a 2nd x-axis as well as second y-axis. Maybe then, you could also create another figure with both stations on same plot. I'm thinking start with this figure, then instead of having just the DS station on the next slide, have the DS station and US stations. If nothing else, it would be good to have the range for the y-axes (discharge and turbidity) and same for both plots.

Methods: Estimation of Suspended Sediment Concentration

Turbidity vs. SSC at Sprague River near Chiloquin (US of reservoir)

N = 66 samples

Turbidity vs. SSC at Williamson River below Sprague River near Chiloquin (DS of reservoir)

N = 48 samples

Cara Walter

Are you going to put the R values in context with typical values from the literature?

Methods: Reservoir erosion

• Repeat cross sections in 2008, 2009 and 2010

• Volume change calculated from differences in reoccupied cross-sections

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

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Results:Longitudinal trends in Sediment Deposition

Cara Walter

It would be nice to have something written on this graph and the next one to help differentiate them. Also, just looking at these two slides, I'm not sure how they fit in with the rest of the talk.

Results:Longitudinal trends in Sediment Deposition

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Results: Reservoir Erosion Volume evacuated

from Reservoir (m3) Mass of sediment evacuated from reservoir (metric tons – r sediment = 1601kg/m3)

WY 2009 2295 3673 (6.8%) WY 2010 1047 1676 (3.1 %) Total 3342 5349 (9.9%)

Results : Downstream SSC

Cara Walter

Maybe add a box to show the zoom in to the next slide?

Results: Suspended Sediment release during drawdown and removal

Results: Annual Suspended Sediment Load

Yearly suspended sediment discharge (in metric tons) above and below the siteof the Chiloquin Dam removal

Site WY 2008 (Nov 16th – Sept 30th)

WY 2009 WY 2010 (Oct 1st to Aug 24th)

During the period of drawdown and in-stream work

(Aug 8th 2008 to Aug 20th 2008)

Upstream: Sprague NR Chiloquin (USGS 1150100)

9200 5250 3900 26

Downstream: Williamson BLW Sprague NR Chiloquin (USGS 11502500)

9600 7450 5250 73

Difference 400 2200 1350 47

Cara Walter

Larger table text would be helpful. Also, tacking on "upstream" and "downstream" to site names. I think a difference row would be good too.

Results: Downstream Differenced DEMs Sprague River Analysis Units

Cara Walter

Is there any way to make the differenced DEMs bigger?

Results: Downstream Net Volume Change- Sprague River Analysis Units

Cara Walter

I think it would be easier to see the gaps between pools if the lines were broken - I think you can do this by inserting a blank row in the spreadsheet between pools. Also, make sure to mention how the volume is scaled.

Results: Downstream Differenced DEMsWilliamson River Analysis Units

Cara Walter

I think it might be easier to look at these if they weren't oriented how they are spatially. Maybe have each pool oriented so flow goes from top to bottom and have the pools go left to right?

Results: Net Volume Change- Williamson River Analysis Units

Results: Sediment Volume deposited in Pool Analysis Units

2008-2009 2008-2010Pool 1 -48 298Pool 2 60 517Pool 3 788 3274Pool 4 27 1352

Pool 1 131 1590Pool 2 -470 1487Pool 3 -15 829

Sprague Pool Units

Williamson Pool Units

Volume Changes in Sprague and Williamson Pool Analysis Units (cubic meters)

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

Cara Walter

I'm finding this figure really challenging to read. Maybe separating it out into more colors? E.g. color separations: 1) sources, 2) sinks, 3) upstream 4) reservoir, 50 downstream?

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.

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.

Acknowledgements

• Dr. Desiree Tullos• Cara Walter• Summer Field Techs– Greg Woloveke, Kaileen Amish, Ryan Caruso,

Adam Wyborny, Meredith Cavanaugh

Questions?

processing of a fine sediment pulse after dam removal sediment budget and longitudinal trends...

Documents

williamson river methods

dam removal line

river diversion

chiloquin dam removal

usgs turbidity

preliminary sediment

fine sediment pulse

pre removal