An Introduction to the National Water Model, The NextGen Framework, and NextGen In A Box
What is the National Water Model?
The National Water Model is the United States' core water prediction framework, offering predictions for the Continental United States (CONUS), Alaska, Hawaii, Puerto Rico, and the U.S. Virgin Islands.
While the model's core implementation is administered by the NOAA's Office of Water Prediction (NOAA-OWP), it is built on free and open-source components, allowing the broader hydrology community to run it locally, make adjustments, and propose changes.
What is the NextGen Framework?
The Next Generation Water Resources Modeling Framework, most frequently referred to as NextGen, is a hydrologic modeling framework that forms the core for modern versions of the National Water Model.
The NextGen Framework aims to resolve current limitations of the National Water Model by transitioning to a highly modular, model-agnostic framework that improves regional interoperability and by making it easier for the hydrology community to append their own models. To enable these tenets, NextGen uses the Basic Model Interface (BMI) to standardize the format of each model's input, output, and properties, thus allowing for models written in any language to quickly be coupled together to create new outputs. These models are combined according to external configuration files, which ensures that all model runs are highly portable and reproducible.
As of version 3.0 of the National Water Model, which was adopted in 2024, the NWM represents a specific configuration of the NextGen Framework, which is freely available for use by the scientific community.
What is NGen?
NGen is the core implementation of the NextGen framework, responsible for administering connections between encapsulated models. While NGen is still under development, it's become an incredibly powerful tool for novel approaches to hydrology.
Unfortunately, these advantages are stymied somewhat by the difficulty of installing NGen. No standard installation process is currently available, instead requiring users to manage a lengthy chain of dependencies, compilers, and environmental conditions. This can already be a time-consuming task for experienced programmers, so for scientists wanting to apply it in their own research, installing and configuring NGen is severely unapproachable. These challenges fundamentally undermine the NextGen framework's core objectives regarding community accessibility and contribution.
What is NextGen In A Box?
Fortunately, there's a solution to this problem! NextGen In A Box is a containerized distribution of the NextGen framework. Containerization is an approach to software distribution and deployment that directly defines the host operating system, dependencies, and run conditions for software, which allows the software to be run in effectively identical conditions regardless of the host system. This means that with NextGen In A Box, anyone can get NextGen up and running in as few as 30 minutes!
Additionally, NextGen In A Box acts as the host platform for a full ecosystem of free, open-source utilities that allow users to customize, evaluate, and visualize their model runs. These tools lower the barrier to entry even further, allowing scientists to seamlessly integrate the NextGen framework into their workflows and produce exciting new discoveries.
If you'd like to get started with NextGen In A Box, check out the NGIAB 101 module, which contains everything you'll need to know to get started.
NGIAB 101 Module