HEC-RAS 6.7 BETA 5 Release Notes & New Features

As of October 31, 2025, HEC-RAS is on version 6.7 BETA 5. While it is still in BETA, it already offers many valuable features. Let's start with the latest and greatest; the full list can be accessed on the Corps website here, or a printed PDF can be found here. A ton of the improved focus remains on piped networks and more detailed 2D methods.

Piped Network Improvements

1. Various Inlet Improvements for Piped Networks

   1. New inlet type: side inlets (think detention pond risers)

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   2. New inlet type: top inlet (replaces drop inlets)

      

   3. Can surcharge only both of these (ie, prevent any inflows)

2. New sluice-style gate inside piped networks

3. Improved Pipe network culvert opening inflows (accuracy improvement)

4. various others

Scour Tools

Includes a new beta version of the 2D bridge scour tools, which add:

1. output variables needed by FHWAs hydraulic toolbox

2. automated output tool to export 2D hydraulics from reference lines directly into a hydraulic toolbox file

   1. Note the scour equations are based on 1D hydraulics. Reference HEC-18 for more information.

   2. The above note out of the way, this will make my workflow much quicker when trying to copy hydraulic inputs into excel, then FHWAs toolbox.

   3. Note that both these tools are fantastic, but can be finicky, so save your work and back it up often.

3. More documentation about using both 2D RAS with the FHWA toolbox (just what we need!)

Momentum from Georeferenced Culverts

This can now be toggled on when using georeferenced culverts in 2D flow areas with the shallow water equations (not on by default). This produces a local circulation including a water jet and water entrainment near the structure.

CPU Affinity (technically a beta 4 update)

This option offers greater flexibility and, in theory, can provide faster runtimes on complex, time-intensive 2D models by forcing RAs to use only the performance cores rather than both p-cores and efficiency cores. As someone who has experimented with overclocking, undervolting, and various other hardware acceleration methods, this is really cool for me. PS, I am running a high-end Lenovo gaming laptop, and followed this Reddit thread for hardware optimization.

USGS Data Download (technically a beta 4 update)

If you have tried to download USGS LiDAR DEMs via the Ras Mapper download, you have probably been frustrated recently. Apparently, there is a new filter option that provides a workaround (although I believe much of the problem lies on the host server side).

Those are the ones that jumped off the page at me. There were also some significant 2D Bridges improvements in previous betas, but version 6.7. Check out the Corps website for the full details, and get out there and model some flood risk!