Gold Ray Dam Removal Monitoring: OSU Summary. Prepared by Desiree Tullos and Cara Walter

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Gold Ray Dam Removal Monitoring: OSU Summary Prepared by Desiree Tullos and Cara Walter December 11, 2012 Data Collection Data collection by Oregon State University consisted of three components on

1 Gold Ray Dam Removal Monitoring: OSU Summary Prepared by Desiree Tullos and Cara Walter December 11, 2012 Data Collection Data collection by Oregon State University consisted of three components on approximately an annual basis: 1) Boat-based bathymetry of the main channel; 2) ground surveys of bars and sloughs; 3) particle counts on bars (Table 1). The longitudinal extent of the surveys varied by survey with the maximum extent from TouVelle State Recreation Site to Valley of the Rogue State Park (Table 1, Figure 1). Boat-based bathymetry was collected from a cataraft with a Teledyne RD Instruments Workhorse Rio Grande ADCP for depth and a Topcon GR-3 RTK GPS using the ODOT network for a remote base station for water surface elevation and location. The same GPS system was used for the ground surveys. The boat-based surveys consisted of 3-5 longitudinal profiles spread across the width of the channel with additional data collected in alcoves (Figure 2). The ground surveys consisted of cross sections in Kelley and Tolo Sloughs, and the reservoir (Figure 2), and grid based sampling on bars including edge of water delineation (Figure 4). Table 1: Types, dates, and locations of data collection Dates Type of data collection Locations July 23 to August Boat-based bathymetry, ground surveys of bars, particle counts of TouVelle to Valley of the Rogue (excluding reservoir for ground surveys) (Pre-removal) bars October 6 to Ground survey of bars and sloughs, particle counts of bars Former reservoir, sloughs, and immediately downstream February 11, Ground survey of bars and sloughs, Former reservoir and sloughs (limited) 2011 particle counts of bars June 15 to 29, Boat-based bathymetry TouVelle to Valley of the Rogue 2011 September 19-21, October 11, 2011 Ground survey of bars and sloughs, particle counts of bars TouVelle to Valley of the Rogue Figure 1: Extent of surveys

2 Figure 2: Locations of data collected in the reservoir near the dam Bear Creek Figure 3: Example bar surveys in the reservoir upstream of the mouth of Bear Creek

3 Data Processing For the boat-based bathymetry data, the GPS and ADCP data were combined to derive the channel bottom elevations at the locations sounded by the ADCP using AdMap, a Matlab program developed by David Mueller at the USGS. Water surface elevations for locations with bad (floating or autonomous) GPS data were determined based upon good (fixed) GPS data upstream and downstream of the locations within the same longitudinal profile, or adjacent longitudinal profiles at the same cross section. For both boat-based and ground-based data collection, locations and elevations of control points were compared between profiles and between surveys to account for differences. Data Analysis A longitudinal profile of the deepest locations in the channel for the main channel for the extent of data collection was created as the first way of comparing annual surveys (Figures 4-9). Boat-based and ground-based data for the main channel were combined to create a Triangulated Irregular Network (TIN) surface for each annual survey using ArcMap. The TIN surfaces were converted to rasters and compared using the Geomorphic Change Detection (GCD) toolbox within ArcMap (Wheaton et al., 2010) (Figures 10). From the GCD analysis, the net change in volume for sections the length of the average channel width (60 m) was extracted and plotted (Figure 11). Cross sections surveyed in the sloughs were plotted for comparison (Figures 12-22). The particle counts were plotted by cumulative percent finer to determine D16, D50, and D84. Since the locations of bars, and therefore particle counts, changed from between annual surveys, the metrics derived from the particle counts (D16, D50, D84) were plotted with respect to distance along the channel centerline (Figure 23-25). Results From a comparison of the longitudinal profile of the thalweg, there is little difference between the 2010 (pre-removal) and 2011 (one year post removal) surveys in the reach upstream of the reservoir (Figure 4) and far downstream (~13.6 km) from the dam (Figure 9). In contrast, immediately upstream of the dam the channel elevation dropped up to 4 meters (Figure 5), and rose up to 2 meters immediately downstream of the dam (Figure 6) with some evidence of pool filling as far downstream as 12 km (Figure 8). In terms of volumetric change, the majority of the erosion occurred within the first 600 meters upstream of the dam (Figure 11). In contrast, the majority of the deposition occurred within 100 to 2800 meters downstream of the dam. There is also noticeable deposition at 12,500 meters from Tou Velle or 4,000 meters downstream from the dam which is the site of a large sand bar. The cross section comparison in the sloughs shows little change in Tolo Slough (Figures 21 and 22) or in the most upstream cross sections of Kelley Slough (Figures 19 and 20). However, large changes (1-2 m of cut) occurred between October 2010 (immediately postremoval) and September 2011 for most of the other cross sections in Kelley Slough (Figures 12, 14-18). From the particle counts, bars coarsened far upstream of the dam, and got finer downstream of the dam (Figures 23-25). However, there were fewer particle counts downstream of the dam in 2011, so it is unclear if there is a trend farther downstream.

4 Figure 4 Figure 5

5 Figure 6 Figure 7

6 Figure 8 Figure 9

7 Figure 10: Example output from GCD analysis: Comparison of 2010 to 2011 for the reservoir Figure 11

8 Figure 12 Figure 13 Figure 14 Figure 15

9 Figure 16 Figure 17 Figure 18 Figure 19

10 Figure 20 Figure 21 Figure 22

11 Figure 23 Figure 24 Figure 25

Channel responses to the removal of Gold Ray and Savage Rapids Dam. Prepared by Desirée Tullos and Cara Water

Channel responses to the removal of Gold Ray and Savage Rapids Dam Prepared by Desirée Tullos and Cara Water Introduction. As the results of extensive efforts over several decades, the Rogue River is now