Humans and Hydroclimate in the United States (H2US)

An Affinity Group Supporting a New Regional Hydroclimate Project in the United States

H2US Mission 

The Humans and Hydroclimate in the United States (H2US) Project is envisioned as a ten-year effort to understand and characterize the water, energy, and carbon cycles (physical processes) in the Anthropocene, driven by a need for useful modeling tools and actionable products developed in collaboration with a multitude of stakeholders to address climate justice, and support water, food, and energy security for natural and human systems in a changing future.

What is a Regional Hydroclimate Project (RHP)?

Global Energy and Water Exchanges (GEWEX) RHPs are generally large, regionally-focused, multidisciplinary projects that aim to improve the understanding and prediction of that region’s weather, climate, and hydrology.

Affinity Group

This web site serves the H2US Affinity Group. We aim to build a diverse, inclusive community of scholars, professionals, and practitioners to broaden participation in multidisciplinary hydroclimate modeling and applications research to enable a convergent science approach.

In December, 2023 the US Regional Hydroclimate Project (US-RHP) Affinity Group was renamed as the Humans and Hydroclimate in the United States (H2US) Affinity Group.

Become an Affinity Group Member


Science Summary Plan

Thematic Research Areas

We identified eight thematic research areas to advance. These are: Human Dimensions, Mountain Hydroclimate, Land-Atmosphere Processes and Coupling, Impactful Extremes, Organized Convection and Precipitating Systems, Advancing Observational Systems, Coastal Processes and Coupling, and the Digital Earth for the U.S (DEUS). Seven Working Groups were formed (see figure) for each theme, who identified the gaps (motivation), core science questions, and some candidate activities for their respective topics, and considered the implied scope. We have not formed a Coastal Processes and Coupling Working Group yet (we are looking for volunteers).

Diagram of H2US working groups and their interdisciplinary approach


Why an RHP?

One of the primary drivers for this project is to reduce the uncertainty in our ability to measure, predict and understand the coupled water, energy and carbon cycles


Diagram of Hydro-climate analysis, prediction, and uncertainty across time and space



The H2US is an opportunity to develop a coordinated, holistic response to hydroclimate change. In the past several years, the US has witnessed hydroclimate events that are without historical precedent (e.g., heat extremes, droughts, fires, relentless coastal storms, flooding, and record snowfalls), and the number of such events are growing. Yet the environmental science community often responds in a disjointed way, as there is no established mechanism to provide the needed coordination and synthesis. The H2US would create a flow of information that is sustained, coordinated, and actionable to the agencies and user communities, as these events and their aftermath unfold. This would help address and align the sizable gaps between the physical and human hydroclimate knowledgebase across the community. It is an opportunity to engage and coproduce science with Indigenous scientists and knowledge holders, in order to develop a more comprehensive and complete understanding of our changing hydroclimatic system. It is also an opportunity to center ideas about engagement, equity, and climate justice in knowledge coproduction and application, to broaden participation in multidisciplinary hydroclimate modeling, observations, and applications research, and to make actionable outputs more accessible and usable to educators and community users. Lastly, this will be a living document and process that will continue to evolve with community input.


Please direct questions/comments about this page to:

Tim Schneider

Sarah Tessendorf

Peter van Oevelen