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DSD-INT 2019 Using D-Water Quality & D-Flow FM to model cohesive sediment transport in San Francisco Bay - White

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Presentation by Sienna White, Stanford University, USA, at the Delft3D - User Days (Day 4: Water quality and ecology), during Delft Software Days - Edition 2019. Thursday, 14 November 2019, Delft.

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DSD-INT 2019 Using D-Water Quality & D-Flow FM to model cohesive sediment transport in San Francisco Bay - White

  1. 1. Using D-Water Quality & D-Flow FM to model cohesive sediment transport in San Francisco Bay Sienna White siennaw@stanford.edu Oliver Fringer fringer@stanford.edu
  2. 2. Past masters theses that contributed to this project: Gostic, M., 2018. Sediment pathways in San Francisco South Bay. Master’s thesis, TU Delft. van Kempen, O., 2017. Sediment pathways in San Francisco South Bay. Master’s thesis, TU Delft. Pubben, S., 2017. 3D mixing patterns in San Francisco South Bay. Master’s thesis, TU Delft.
  3. 3. San Francisco Bay
  4. 4. North Bay San Pablo Bay South Bay Central Bay Suisun Bay
  5. 5. gold greed 850 million m3 of sand Moftakhari, H., Jay, D. A., Talke, S. A., Schoellhamer, D. H., 2015. Estimation of historic flows and sediment loads to San Francisco Bay , 1849–2011. Journal of Hydrology 529, 1247–1261.
  6. 6. Shirzaei, Manoochehr, and Roland Bürgmann. "Global climate change and local land subsidence exacerbate inundation risk to the San Francisco Bay Area." Science advances 4, no. 3 (2018). Why does sediment matter? muddy water = cleaner water contaminant tracking flood protection
  7. 7. Jaffe, B., Foxgrover, A. C., 2006. A history of intertidal flat area in South San Francisco Bay , California: 1858 to 2005. Tech. rep., US Geological Survey.
  8. 8. 1. How does sediment influx from local tributaries in South Bay affect sediment transport in South Bay? 2. How do wind waves affect sediment transport in South Bay? 3. What is the net sediment flux at the Dumbarton Bridge during water year 2013? Research Questions:
  9. 9. Hydraulic characteristics of San Francisco Bay Tides: standing waves in South Bay, strong M2 & K1 constituents at the Golden Gate Bridge
  10. 10. Hydraulic characteristics of San Francisco Bay Byxbee Park, Palo Alto ~2pm Waves: fetch-limited in SFB. Parameterized in our model via bottom shear stress (Grant & Madsen 1979).
  11. 11. [fun] cohesive sediment properties Sediment characteristics of San Francisco Bay
  12. 12. Bed Consolidation
  13. 13. Flocculation
  14. 14. Footage courtesy of Daniel Livsey, USGS
  15. 15. [fun] cohesive sediment properties!
  16. 16. Boundary Forcings Initial Condition Hydrodynamics D-Water Quality DELWAQ Model DELWAQ Input + switch on relevant processes, define parameters.
  17. 17. Boundary Forcings Initial Condition Hydrodynamics D-Water Quality DELWAQ DELWAQ Input Freshwater predicted with hydrologic model, SSC calculated with rating curves Equilibrium bed composition estimated using averaged bottom shear stress D-Flow FM model
  18. 18. Model Results
  19. 19. Bever, A. J., MacWilliams, M. L., 2013. Simulating sediment transport processes in San Pablo Bay using coupled hydrodynamic, wave, and sediment transport models. Marine Geology 345, 235–253.
  20. 20. SSC transport during a tidal cycle
  21. 21. Deposition & erosion in the fluff layer over a tidal cycle
  22. 22. Define transects for cumulative sediment flux calculation @ the Dumbarton Bridge
  23. 23. USGS Preliminary Data Livsey, DN, Downing-Kunz, M, and Schoellhamer, D. (in review) The effect of flocculation on suspended-sediment flux measurements in tidally affected systems. Cumulative Sediment Flux at the Dumbarton Bridge
  24. 24. Effect of minor tributaries on sediment flux
  25. 25. Effect of waves on sediment flux
  26. 26. Answering our research questions: 1. How does sediment influx from local tributaries in South Bay affect sediment transport in South Bay? a. Minor tributaries increase sediment import at the Dumbarton into South Bay on the order of 16% (likely a minimum). 2. How do wind waves affect affect sediment transport in South Bay? a. Waves decrease SSC variance in South Bay by damping deposition during ebb and slack tide, and such, increase residual sediment flux into South San Francisco Bay. 3. What is the net sediment flux at the Dumbarton Bridge during water year 2013? a. The net flux is positive → 525.7 ktons moving landward over October 2012 - October 2013.
  27. 27. Open source: accessible to a broader scientific community Can calculate sediment budgets + flux for transects difficult to access in situ. Strengths Validation difficult/weak with sparse data availability No mass exchange between sediment classes No spatial/temporal variation in sediment properties and dynamics Weaknesses Applicable sediment model for SSC signals on spring-neap time scales No feedback between hydrodynamics + morphodynamics Quick runtime: ~ 4 days of wall-clock time to run 5 months on a 64-bit 16 core AMD Opteron processor (clockspeed 2.3 Ghz)
  28. 28. 1. Minor tributaries increase sediment import at the Dumbarton into South Bay on the order of 16% (likely a minimum). 2. Waves decrease SSC variance in South Bay by damping deposition during ebb and slack tide and thus increase residual sediment flux into South San Francisco Bay. 3. The net flux is positive → 525.7 ktons moving landward over October 2012 - October 2013. Acknowledgements: Joe Adelson at Stanford; Daniel Livsey and Maureen Downing-Kunz at USGS; Emma Nuss, Rusty Holleman, Allie King, and Zhenlin Zhang at the San Francisco Estuary Institute; Mick van der Wegen all the TU Delft students who worked on developing this model: Michelle Gostic, Oxana van Kempen, Fernanda Achete, and Silvia Pubben; and Arjen Markus at Deltares. Thank you & questions !

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