Proposal Figures

Figure 1: The Manning, Chézy, and Darcy-Weisbach equations are commonly used in engineering and flood models. All three contain poorly-constrained friction factors that can be related to the ratio of average velocity to shear  velocities. The U ̅⁄U*  ratio serves as a dimensionless resistance factor in this study.

Figure 2: Rivers produce seismic energy by a variety of sources, including saltating bedload and turbulence. This study will focus on the turbulent flow signal. We will discriminate between the turbulent flow and bedload transport frequency bands based on the presence/absence of hysteresis during a flood. Figure form Larose et al. (2015).

Figure 3: Flowing water likely produces both Love and Rayleigh Surface waves. In the Gimbert et al. (2014) and Tsai et al. (2012) models, only Rayleigh energy production is approximated. This study seeks to evaluate that assumption via waveform polarization analysis. Diagram after Shearer (2009).

Figure 4: At Oroville dam, California, high flow release volumes and emergency spillway releases ultimately led to large amounts of erosion. A nearby seismometer in the UC Berkley Seismic Network is able to observe the seismic energy created by the high flow volumes interacting with emerging roughness in the spillway. Estimated outflow during this photo is 2,800 meters per second. Photo Credit: Dale Kolke / California Department of Water Resources on 2/15/17

Figure 5: The BK ORV seismometer used in this study is sensitive to the discharge volumes reported by the California Department of Water Resources. With higher discharges (blue line; right axis), more power is observed at a wide range of frequencies in the 1-20 Hz band. (color axis, left axis). The period shown is from January 1st to March 5th, 2017.

Figure 6: Diagram illustrates the three-component polarization analysis methodology used in this study (adapted from Koper and Hawley (2010). Oroville Dam and Northwest Branch data will both undergo this analysis. The planarity, linearity, incidence angle, and azimuths of the seismic energy at each frequency can be computed using this method.

Figure 7: The study river is the Northwest Branch of the Anacostia River, which crosses the Atlantic Fall Line, and ranges in morphology from a bedrock Knick zone to a gravel-bed river. We will evaluate this method at the three channel morphologies. Due to urbanization in the watershed, flood responses to storms are quick and intense.

Figure 8: This figure illustrates the experimental setup at the three study reaches on the Northwest Branch of the Anacostia River. Buried three-component seismometers will record continuously for 30 days at a time, with a sampling frequency of 500 Hz. Pressure Transducers will continuously collect water depth and water surface gradient. The bed grainsize distribution (D84) will also be collected at each channel cross section. 

Figure 9: Preliminary findings from one-component seismic analysis of a riffle-pool sequence in Paint Branch Creek, Maryland in May 2016. Due to variability in flow regime and background noise, five 30 second recordings were collected at 24 geophones arrayed at 12 cross sections along the stream. We observed higher frequencies at hydraulically smooth channel sections with less flow resistance (higher U/U* values). This may reflect a difference in signal from bed resistance (low U/U* values) and internal distortion resistance.