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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.



  • Forecasting and hindcasting of water levels to assist with emergency response decisions, infrastructure operations, resource allocation for current and potential sea level rise scenarios.

  • 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.

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.

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.

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:

1. Download the Model

Model grid, boundary conditions, and wind forcing for WY1951-2019.


2. Download processed model results

Processed model results for 1244 points across the SF Bay for WY1951 - WY2019 for those wishing to access the data without running the SWL Model (for using data without running model)


3. Download extreme, still, and total water level data

Includes shapefiles and analysis results for extreme, still, and total water level across the SF Bay.


When using one or more of the downloads, please include the following references: ·

  • 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.

  • 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,

  • 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.

  • 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.

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

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