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ALPHA

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Getting Started | Announcements | YouTube

Foreword

The HEC-RAS team is excited to present the RAS 2025 Alpha!

Today, RAS is still built on the foundational code that began in 1993. Technology and engineering have changed dramatically since then; we have access to multi-core computers, gigabit networks, cloud computing, and a wealth of software that wasn't conceivable 30 years ago. To meet the needs of today and of the future, it was necessary for us to invest in the next generation of our software.

This will be a long road - RAS has 30 years of amazing capabilities which we can't reproduce overnight. RAS 2025 is certainly a work-in-progress, but we believe it has evolved far enough to let people explore our vision of the next generation. We know many of you are as excited as we are to dive in and start using the software. Please be patient with the rough edges, and help us by providing feedback and bug reports to shape the development of the new river analysis system!

Welcome to the future of hydraulic modeling.

Interface

Modern UI

HEC-RAS has a brand new interface, built from the ground up. The original HEC-RAS 1.0 was designed in 1993, built around tabular data entry with basic geometry schematics. Today’s technology landscape is vastly different from 30 years ago, and has changed what we expect from software. Welcome to the new RAS!

In-App Updates (No Admin Required)

HEC-RAS 2025 is built for portability - everything it needs is self-contained. You can update, distribute, and download copies without worrying about administrator rights. Seamless feature updates are delivered within the software itself - with a single click, a small patch is downloaded, applied, and the software reboots into the new version. Looking ahead, expect an enhanced UI to manage side-by-side installs and multiple feature/stability channels.

Hybrid Workstations

The last decade has introduced multi-monitor setups, high-resolution displays, and hybrid office/telework conditions. Our flexible docking system and dynamic UI layout is designed to work with modern workstations.

Meshing

Mesh Generation

The HEC-RAS 2025 mesh generation system has been completely redesigned. Gone are the days wasting hundreds of hours painstakingly moving cells, only to be met with fatigue and frustration. Breaklines enforce faces, period.
From the inception of 2D modeling in HEC-RAS 5.0, meshes were cell-centric. Engineers would move cell center points, trying to convince the mesh generation system to put faces in the correct location. The new RAS mesh generation is now face centric.

Mesh Development Tools

Users digitize arcs in a 'conceptual' mesh, conveying intents like cell-size, shape, growth rates, and orthogonality. This mesh blueprint allows us to quickly build higher-quality computational meshes from simple inputs. This flexibility allows for quick and easy mesh manipulation at any point during model development.

New Mesh Types

Quadrilateral meshes conform to channel curvature, while cartesian and triangular meshes are better suited for 2D overland flow scenarios. Each mesh type includes post-processing routines to enhance mesh quality, improving stability and reducing model run-times. The goal is to give users intuitive controls to experiment with cell sizes, making mesh refinement and adjustments easier than ever before.

Export to HEC-RAS 6.6

You don't have to wait a year to use the new meshes in your system - meshes built in RAS 2025 can be exported and run from version 6.6.

More Control

The mesh generation rework places a strong emphasis on reliable breaklines and arc interactions. With this system, you can follow ridges and valleys more accurately, create holes in the mesh, and carefully guide the flow of mesh cells through the domain.

Mapping

Base Maps

RAS now has default base maps! Vector data is projected just-in-time, so text is crisp and legible. Powered by the Open Street Maps and USGS hillshade datasets.

Performance

When RAS was born, hard drives were 8MB. Now, terrains are 8GB. Data size is increasing exponentially, and our tools need to scale to meet the challenge. Raster importing and rendering is 10-50x faster in the new version of RAS.

Geospatial First

Fewer tables, more charts and maps. Most data in RAS can be manipulated directly from the map window.

New Foundation

New Explicit Solver

RAS 2025 brings an all-new compute engine. As the world's hardware scales to higher core counts, we had to re-evaluate and redesign our compute engine to scale with it. Building the compute engine and UI in a single package allows a brand new set of tools that were previously impossible. RAS now renders results as they're running, allowing you to get early feedback on your model results.

Designed for the Cloud

RAS runs on Linux, and is designed for a cloud-friendly future. It runs inside a container for ultimate portability and flexible distribution.

API

Over the past decade, a burgeoning collection of tools and scripts have emerged from the community to support our users and their models. We want to support these groups with a documented, public API to build the next generation of tooling around RAS.

Simplified File Management

No more project.g17.hdf! If you want to create a backup of a mesh or send it to a coworker for review, you can simply copy {GeometryName}.h5 and send the file. What you see is what you get.

Modern Code

RAS 2025 was written from scratch in C#.NET, with performance and quality assurance testing in mind. Modernizing and centralizing from 4 programming languages into 1 will help focus the team for more efficient and reliable feature delivery.

Connectivity

Web Connectivity

More of the data you need is connected directly in the UI. We're building importers for NLCD, NOAA Precipitation, USGS terrain, and USGS stream gauges, with more to come.

RAS has a combined search bar, letting you search for relevant commands ("Create new N-Value Layer"). We also search our documentation portal, linking to relevant sections of help text.

Example Projects

Example projects are now available directly from the main launch screen, tagged with relevant data and fully searchable. These projects are designed to be a primary teaching tool for new engineers and a convenient test playground for the latest features. When new features like infiltration are released, you'll have access to sample datasets with calibrated setups, ready to download from the interface.

Demos

We are starting a new series of videos in RAS2025 to showcase the new workflows and improved features! Expect more to come.

Roadmap

In the spirit of transparency, we would like to share our future roadmap with you. Please keep in mind these are coarse targets; roadmaps can slip if certain features take longer than expected or as priorities shift. We're still learning about our new development velocity while simultaneously supporting version 6. We would like to emphasize that this will be a multi-year journey before we start to hit feature parity with classic RAS.

2025

2026

2027

Alpha releases every 2-4 weeks with new features, bug fixes, and performance improvements

Mesh generation advancements

Precipitation

Basic Structures

Basic Terrain Modifications

Improved v6 Model Importer

Initial GPU Solver

1D/2D hybrid solver

1.0 release in late Fall 2025. Multiple feature/bug-fix releases throughout the year.

Advanced Terrain Modifications

Advanced Structures (Bridges/Gates/Pumps)

Advanced Mesh Post-Processor tooling

Advanced 1D Solver and Mesh enhancements

Extreme scale multi-resolution Mesh improvements.

Improved Boundary Conditions (Rating Curve, Multi-Variate)

Initial Conditions

Breaching

2.0 release (tentative). Multiple feature/bug-fix releases throughout the year.

Geometry & Boundary Condition clipping: import and export.

Sensitivity analysis framework

Project management features (model delta charts, summary reports)

Improved inundation mapping, particularly with precipitation and shallow flow

Implicit 2D solver

FAQ

What is happening with the HEC-RAS 6.X?

We understand how important existing models and capabilities are to everyone. We will support HEC-RAS version 6 with bug fixes, training classes, and user support for many years to come.

Can I forward migrate my existing HEC-RAS model?

We have a migration utility to port version 6 models into 2025. The geometry and solver are fundamentally different in the new generation, so models will need work to run and calibrate in the new software. Our migration tool will improve over time as we add more features to the new software.

When will HEC-RAS 2025 officially be released?

Our target is to have an alpha period of approximately 1 year, officially releasing the software in Fall 2025.

Can I use the RAS 2025 Alpha for studies and production work?

Please don't.

What about 1D Hydraulics?

Our current focus is on 2D hydraulics and improvements in the meshing system. 1D hydraulics will come later, but 1D models in the future may look different than what you are used to currently. More details will come later.

How can I provide feedback or report bugs?

Bug reports are now available directly from the UI! Please file them if you experience any software glitches or crashes. We are likely to receive a high volume of similar reports, so we will only reach out to you if we need your model to reproduce the issue.

We also anticipate a large amount of feedback and excitement in the early days of the alpha, so we're limiting feedback channels while we get our feet underneath us. We're well aware of the existing pain points in the alpha, and our next year of development and feature deliveries is fairly rigid. We're still investigating mechanisms to receive feedback that scale better than email - more to come on that later.

Open RAS 2025 > Help > Report Bug

This will be a long journey, but we're incredibly excited for what the future holds. From the entire HEC-RAS Team, thank you!

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Getting Started | Announcements | YouTube