SRH-2D, Sedimentation and River Hydraulics – Two-Dimensional model, is a two-dimensional (2D) hydraulic, sediment, temperature, and vegetation model for river systems under development at the Bureau of Reclamation. Different versions of SRH-2D contain different modules, as listed below:

  • SRH-2D version 2: Modeling of flow hydraulics for stream/river systems
  • SRH-2D version 3: Mobile bed sediment transport module added to v.2
  • SRH-2D version 4: Temperature and vegetation module added to version v.2

For watershed runoff modeling, SRH-W v.1.1 should be used which is listed at the bottom.

About SRH-2D version 2

SRH-2D version 2 solves the 2D dynamic wave equations, i.e., the depth-averaged St. Venant equations. Its modeling capability is comparable to some existing 2D models but SRH-2D claims a few boasting features. First, SRH-2D uses a flexible mesh that may contain arbitrarily shaped cells. In practice, the hybrid mesh of quadrilateral and triangular cells is recommended though purely quadrilateral or triangular elements may be used. A hybrid mesh may achieve the best compromise between solution accuracy and computing demand. Second, SRH-2D adopts very robust and stable numerical schemes with a seamless wetting-drying algorithm. The resultant outcome is that few tuning parameters are needed to obtain the final solution. SRH-2D was evolved from SRH-W which had the additional capability of watershed runoff modeling. Many features are improved from SRH-W.

Major Features of SRH-2D v.2

Major SRH-2D capabilities are listed below:

  • 2D depth-averaged dynamic wave equations (the standard St. Venant equations) are solved with the finite-volume numerical method;
  • Steady state (with constant discharge) or unsteady flows (with flow hydrograph) may be simulated;
  • An implicit scheme is used for time integration to achieve solution robustness and efficiency;
  • An unstructured arbitrarily-shaped mesh is used which includes the structured quadrilateral mesh, the purely triangular mesh, or a combination of the two. Cartesian or raster mesh may also be used. In most applications, a combination of quadrilateral and triangular meshes is the best in terms of efficiency and accuracy;
  • All flow regimes, i.e., subcritical, transcritical, and supercritical flows, may be simulated simultaneously without the need for special treatments;
  • Robust and seamless wetting-drying algorithm; and
  • Solved variables include water surface elevation, water depth, and depth averaged velocity. Output variables include the above, plus Froude number, bed shear stress, critical sediment diameter, and sediment transport capacity.

SRH-2D is a 2D model, and it is particularly useful for problems where 2D effects are important. Examples include flows with in-stream structures, through bends, with perched rivers, with side channel and agricultural returns, and with braided channel systems. A 2D model may also be needed if one is interested in local flow velocities, eddy patterns, flow recirculation, lateral velocity variation, and flow over banks and levees.


SRH-2D version 3 (latest version)

  • SRH-2D version 3.2.0 Distribution Package (March 2017) (ZIP 61.1 MB)

SRH-2D version 2

  • SRH-2D version 2.2 Distribution Package (February 2016) (ZIP 66 MB)
  • "What’s New With Version SRH-2D Version 2.2?" (August 2012) (DOC 16 KB)
  • SRH-2D version 2 Theory and User's Manual (November 2008) (PDF 2.4 MB)
  • SRH-2D version 2 Distribution Package (2009 [November 2008]) (ZIP 3.5 MB)
  • Papers/Presentations:
    • Lai, Yong G. 2009. Two-Dimensional Depth-Averaged Flow Modeling with an Unstructured Hybrid Mesh. Paper/Presentation. (PDF 424 KB)
    • Lai, Yong G. 2007. 2D Flow Modeling With SRH-2D. MS PowerPoint Training Presentation (PDF 9.9 MB)

SRH-W version 1

  • SRH-W version 1.1 Theory and User Manual (2007 [November 2006]) (PDF 11.2 MB)
  • SRH-W version 1.1 Distribution Package (2007) (ZIP 11.4 MB)
  • SRH-2D Beta (July 2012) (ZIP 58.4 MB)
  • Papers/Presentations:
    • Lai, Yong G. 2006. Watershed Simulation with an Enhanced Distributed Model. Paper/Presentation. Federal Interagency Sedimentation Conference in Reno, Nevada, April 2-6, 2006. (PDF 779 KB)
Last Updated: 3/27/17