1D-2D Still Water Level (SWL) Model
The 1D-2D Still Water Level (SWL) Model is a one- and two-dimensional (1D and 2D) model of the San Francisco Bay-Delta for detailed analysis of hydrodynamics, including still water levels and tide/surge in the San Francisco Bay and Sacramento-San Joaquin Delta.
Applications
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Forecasting and hindcasting of water levels to assist with emergency response decisions, infrastructure operations, resource allocation for current and potential sea level rise scenarios.
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Assess the effectiveness of planned flood protection measures against extreme tidal and non-tidal events.
Model Description
The 1D-2D SWL Model uses a high resolution (~100m) LiDAR mesh to model the effects of meteorological and fluvial forcing on coastal water levels. The model covers the Delta up to the approximate upstream limit of tidal influence and extends seaward to the Pacific Ocean.
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1D-2D SWL Model was developed from a 70-year record from 1950-2019. This 70-year hindcast simulation was used to estimate extreme values of water levels and their matching return periods.
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The 1D-2D Model does not simulate the impacts of wave setup and runup on the water level, as the impacts from wave-driven processes was found to be limited. For example, for 75% of the analyzed points around the Bay, waves were found to contribute less than 10% to extreme conditions compared to Mean Higher High Water (MHHW). More information on the impacts of wave processes will be published soon.
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The 1D-2D SWL model was developed using open-source Delft3D-Flexible Mesh software.
Download the 1D-2D SWL Model
Third parties can run, amend, copy, and distribute this SFBD-SWL and other SFBD Community Models under a Creative Commons Attribution-Share Alike 4.0 International License:
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Model grid, boundary conditions, and wind forcing for WY1951-2019.
2. Download processed model results
Processed model results for 1,244 locations across San Francisco Bay for WY 1951–2019, providing easy access to precomputed model outputs without the need to run simulations.
3. Download 2021 Extreme, Still, and Total Water Level Data
Includes shapefiles and analysis results of extreme, still, and total water levels across San Francisco Bay as developed in Nederhoff et al. (2021). Note: This dataset only includes current-day conditions and does not account for sea level rise (SLR).
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​4. Download 2025 Extreme Still Water Level Data (Updated Analysis – In Review)
Includes shapefiles and analysis results across San Francisco Bay, based on an updated study from 2025 (paper in review). Expanded from analysis done in 2021: This dataset incorporates four different Bay configurations and evaluates two sea level positions: current sea level and +1.5 meters (4.92 feet) of sea level rise. This dataset provides a more comprehensive assessment of how different shoreline configurations and SLR scenarios influence extreme water levels.
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Citation
When using one or more of the downloads, please include the following references: ·
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Deltares USA (2023). Coastal and Riverine Flood Assessment for Alameda County Flood Control District - Delft3D FM and SWAN model development and application for derivation of extremes across the San Francisco Bay. Report version 10. September 20, 2023. Download the report here.
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Nederhoff, K., Saleh, R., Tehranirad, B., Herdman, L., Erikson, L., Barnard, P. L., & van der Wegen, M. (2021). Drivers of extreme water levels in a large, urban, high-energy coastal estuary – A case study of the San Francisco Bay. Coastal Engineering, 170, 103984. https://doi.org/10.1016/j.coastaleng.2021.103984
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Tehranirad, B., Nederhoff, C.M., Herdman, L.M., and Erikson, L., 2021, Hydrodynamic model of the San Francisco Bay and Delta, California: U.S. Geological Survey, https://doi.org/10.5066/P9WWB9V4
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Tehranirad, B., Herdman, L., Nederhoff, K., Erikson, L., Cifelli, R., Pratt, G., Leon, M., & Barnard, P. (2020). Effect of fluvial discharges and remote non-tidal residuals on compound flood forecasting in San Francisco Bay. Water (Switzerland), 12(9), 1–15. https://doi.org/10.3390/w12092481
Terms of Use
The data provided on this website is provided 'as-is' with absolutely no warranty whatsoever, whether express or implied, as to the accuracy, thoroughness, value, quality, validity, suitability, condition, or fitness for a particular purpose, nor as to whether the data or models are error-free, up-to-date, complete, or based on accurate or meaningful facts.
The data and models are provided on the condition that neither Deltares USA, Alameda Flood Control District, California Department of Water Resources, the U.S. Geological Survey nor the U.S. Government can be held liable for any damages resulting from the authorized or unauthorized use of the data. Any use of the data is at the user’s sole risk.
Alameda Flood Control District © 2019-2021, use allowed under the terms of Attribution-ShareAlike 4.0 International
