By: Kristy Riley, P.E., PMP

HEC-RAS Update: Closing a 30-Year Chapter, Building the Next Generation

The Hydrologic Engineering Center's River Analysis System (HEC-RAS) team has been busy on many fronts—supporting today’s modeling needs while also laying the foundation for the next 30 years of hydraulic analysis. With the final feature release of the current software line and rapid progress on our rewrite, we’re at an exciting transition point for the HEC-RAS community.

HEC-RAS 7.0: The Final Feature Release of “HEC-RAS Classic”

In April, the HEC-RAS team delivered HEC-RAS 7.0, the final feature release for the software line that has served the water resources community for more than three decades. This codebase—soon to be informally known as “HEC-RAS Classic”—has grown and evolved dramatically since the first public release in 1995. Over time, new capabilities were added (unsteady flow, geospatial tools, sediment, water quality, 2D modeling, and much more), and with that success came complexity: nearly 3 million lines of code across multiple programming languages.

That growth made continued feature development increasingly difficult and risky. So, after careful consideration, we made a deliberate decision: HEC-RAS 7.0 is the last feature release for that line.

This does not mean the software is going away. We know many agencies and firms have made major investments in HEC-RAS models and workflows. HEC-RAS Classic will remain supported with bug-fix releases for years to come, and we want users to feel confident that existing projects can continue to be maintained and executed successfully.

Why 7.0 is a “major” release

HEC-RAS 7.0 marks a significant milestone: stormwater pipe networks are no longer a beta feature.

Stormwater pipe networks were first introduced as a beta capability in HEC-RAS 6.6, and since then we’ve steadily expanded and refined the feature set based on testing, user feedback, and validation work. With 7.0, the beta tag has been removed—signaling that pipe networks are now a fully supported part of the HEC-RAS toolkit.

Stormwater pipe networks: expanding urban and pluvial flood modeling in RAS

The pipe network capabilities allow users to build and simulate closed conduit systems and integrate them with 1D and 2D surface elements. This expands the applicability of HEC-RAS in urban environments—supporting evaluations of stormwater system adequacy and improved characterization of pluvial flooding risk.

Across the HEC-RAS 6.7 beta releases, we added many key enhancements to make pipe networks more useful for real-world stormwater work, including:

  • Additional conduit shapes and improved plotting/visualization tools
  • Expanded property tables and cross-section/profile viewing
  • Speed improvements (including “speed draw” workflow enhancements)
  • Side inlets, top inlets, and manhole functionality
  • Hydraulic structures and losses (gates, weirs, entrance/exit losses)
  • Specialized junction losses, including junction angle losses and plunge losses

Releasing HEC-RAS 7.0 was also about more than one headline feature. The team spent substantial time wrapping up improvements, addressing bugs, tightening workflows, and resolving loose ends—with the goal of leaving that line in a strong, stable place for long-term use.

HEC-RAS 2025: The Rewrite Is Moving Fast

While finalizing 7.0, we’ve also been developing the next-generation software: HEC-RAS 2025—an effort comparable in significance to the transition from HEC-2 to HEC-RAS in the early 1990s. The rewrite is about giving the modeling community a modern, sustainable platform: a codebase and interface designed for today’s computing environment, and flexible enough to support new capabilities well into the future.

We released the HEC-RAS 2025 Alpha in October 2024, and since then we’ve been publishing updates on an approximately 6–8 week cadence. The feedback and bug reports have been invaluable, and the software has advanced rapidly as a result. With recent progress, the team the team released a beta version at the end of March 2026.

Building Capacity: Nationwide USACE Training for RAS 2025

A major focus over the first half of 2026 has been training and knowledge transfer. The team has been traveling nationwide to provide HEC-RAS 2025 training to USACE subject matter experts, partnering with each Division to host regional sessions. This approach is designed to scale expertise efficiently: attendees return to their Districts prepared to support local staff and help expand internal capability.

  • Pilot training hosted at HEC in December 2025
  • Eight classes taught nationwide in January-April 2026
  • 200+ USACE engineers trained

We are recording the training sessions and plan to publish the videos and materials to our website and YouTube channels in the coming months.

What’s Next

In the near term, our priorities are:

  • Delivering new updates to the HEC-RAS 2025 Beta version
  • Making recent advancements more visible to the broader user community
  • Continuing to stabilize workflows and incorporate feedback from training and early adopters
  • Maintaining ongoing bug-fix support for HEC-RAS Classic, recognizing the long lifecycle of major hydraulic models

We know transitions can be challenging—especially when users have decades of experience and investment in a trusted tool. Our goal is to make this transition as smooth as possible: keeping Classic reliable for established workflows while offering a compelling, modern path forward in HEC-RAS 2025.