Community NextGen 2026

Model integration in NextGen, NGIAB and NRDS

Day 1 Session 1

Josh Cunningham, AWI
Jordan Laser, Lynker
Harsha Vemula, AWI
Quinn Lee, AWI
Nia Minor, AWI
Gio Romero, Aquaveo
Arpita Patel, AWI
Nels Frazier, Lynker
Zach Wills, Lynker

This workshop explores the complete lifecycle of contributing BMI-compliant models to the NextGen Framework, NGIAB (NextGen In A Box), and the NextGen Research DataStream (NRDS). This hands-on session will equip you with the knowledge to navigate the model integration pathway from development through potential operational deployment.

Starting with BMI (Basic Model Interface) documentation, we’ll guide participants through the model integration checklist, contribution form and demonstrate how containerization via NGIAB’s “plugin” system enables modular model addition without direct Dockerfile editing. We’ll cover the technical requirements for model contribution, including BMI compliance verification, configuration standards, and testing protocols across Docker environments. Finally, the NGIAB Visualizer will also be used to explore local model results.

The workshop will then demonstrate how models integrated into NGIAB can become available through NRDS: the continuously running research platform generating daily NextGen outputs on AWS. We’ll discuss how this creates an immediate research-to-operations pathway where community model improvements can be tested, evaluated, and potentially adopted for operational forecasting. Additionally, we’ll address the organizational and technical considerations for sustainable community model integration: version control strategies, security considerations for model robustness, documentation standards, and coordination with Community Resources Working Groups to ensure community contributions align with framework evolution toward NWM 4.0.

The NextGen ecosystem is advancing toward a truly community-driven hydrological modeling framework through standardized model integration pathways. Join us to learn how you can contribute your hydrological models to the Community NextGen ecosystem, whether you’re developing new process representations, implementing regional adaptations, or advancing existing model formulations.

Getting Hands-on with the CIROH Community HydroFabric

Day 1 Session 2

Tony Castronova
James Halgren
Irene Garousi-Nejad
Josh Cunningham

This interactive workshop will introduce attendees to an ongoing effort to not only make the NextGen Hydrofabric open and accessible, but also at lowering the barriers to accessing, using, and contributing to these essential CIROH datasets. Attendees will be introduced to the CIROH Community Hydrofabric cyberinfrastructure, a new system that enables researchers to contribute to and adapt hydrofabric datasets while maintaining alignment with NOAA’s operational standards. This workshop will introduce the work undertaken to provide access to  community-maintained research versions of the hydrofabric, provide a hands-on exploration of access and data management capabilities designed to support innovative NextGen modeling activities, and present a framework for contributing enhancements through well-defined processes. The workshop will demonstrate practical applications showing how community knowledge can be integrated into the hydrofabric, and provide foundational skills in exploring, subsetting, and utilizing hydrofabric datasets for your own research applications. Whether you’re working on model calibration, parameter development, or exploring new modeling capabilities, this workshop will equip you with the tools and knowledge to engage with this critical infrastructure supporting the future of water prediction.

Orchestrating end-to-end reproducible NextGen and NextGen adjacent workflows: Part 1: Model setup and configuration

Day 2 Session 1

Darri Eythorsson, University of Calgary
Raymond Spiteri, University of Saskatchewan
Jordan Read, CUASHI
James Halgren, Brigham Young University
Martyn Clark, University of Calgary

In this workshop, we will go through the exercise of setting up and executing a full modelling workflow for NextGen or a NextGen-adjacent model using intelligent workflows. This will include community solutions for key components of the NextGen ecosystem (e.g., static data acquisition, domain definition and discretization, forcing data acquisition and model input pre-processing, default model instantiation, model optimization and evaluation). In the first session of the workshop, participants will select a USGS gauging station and build and optimize a model for the watershed upstream of it. At the end of the first session, participants will have a model that has achieved demonstrable improvement through sequential calibration methods. We will discuss best practices for reproducibility and provenance management throughout the workflow. We will consider key model decision points, discuss alternative model design structures, and assess their impact on model performance. We will discuss the sources of uncertainty in the model workflow and methods for characterizing and estimating them.

Orchestrating end-to-end reproducible NextGen and NextGen adjacent workflows: Part 2: Orchestrating parallel model calibration

Day 2 Session 2

Raymond Spiteri, University of Saskatchewan Darri Eythorsson, University of Calgary
Jordan Read, CUASHI
James Halgren, Brigham Young University
Martyn Clark, University of Calgary

In the second session of this workshop, we will discuss the technical challenges associated with establishing and maintaining the computational environment required to use HPC resources to calibrate NextGen models for both individual watershed studies and large-sample and continental-domain experiments. We will perform a parallel calibration exercise using the model developed in the first workshop session, demonstrating the utility of massively parallel computing resources for large-domain hydrological modelling.

In both sessions, we will discuss best practices for reproducibility and provenance management throughout the workflow. We will consider key model decision points, discuss alternative model design structures, and assess their impact on model performance. We will discuss the sources of uncertainty in the model workflow and methods for characterizing and estimating them.

Theory and Applications of Uncertainty Analysis for Extreme Event Hydrometry

Day 3 Session 1

Mohamed Abdelkader, University of Iowa
Marian Muste, University of Iowa,

This workshop provides an introduction to the theory and practical implementation of Uncertainty Analysis (UA) in hydraulic measurements and hydrometric applications, with emphasis on how uncertainty in observed hydrological variables propagates into hydrological model calibration and validation.

Participants will explore:

Terminology and Concepts of uncertainty analysis, including accuracy, error, bias, precision, confidence levels, and probability distributions commonly used in hydrology.

Uncertainty Analysis Frameworks, with an overview of standardized approaches and their relevance to hydrometric measurements used as inputs to hydrological models.

GUM Implementation Methodology, based on the Guide to the Expression of Uncertainty in Measurement (GUM), including Data Reduction Equations (DREs) and sensitivity coefficients.

GUM Implementation Examples, demonstrating how uncertainty propagates through measured hydrological variables such as discharge and water level, and how to quantify the uncertainty budget and confidence intervals.

Developing a physics-based modeling framework to predict water quality from hillslope to watershed scales

Day 3 Session 2

Jesus Gomez-Velez, University of Iowa
Felipe Quintero, University of Iowa
Ruben Molina, University of Iowa
Larry Weber, University of Iowa

This workshop introduces students to the conceptualization and implementation of a physics-based modeling framework to predict water quality from hillslope to watershed scales. It emphasizes fundamental concepts, including design and implementation decisions on the model structures, boundary and initial conditions, and forcing factors. As a practical example, the course examines the fate and transport of nitrate in heavily managed agricultural areas. Participants will use a new water quality module integrated into the Hillslope Link Model (HLM), developed at the University of Iowa.