Building drought early warning systems for fisheries and water management across the U.S.
As droughts become more frequent and severe, freshwater ecosystems and the valuable fisheries they support face increasing challenges. Drought reduces streamflows, raises water temperatures, and stresses fish populations, particularly cold-water species like trout. These impacts can lead to declines in trout populations, threatening biodiversity, ecosystem health, and local economies. To address these threats, scientists at the USGS Northern Rocky Mountain Science Center and Montana State University are developing Drought Early Warning Systems (DEWS) to help resource managers better understand and manage drought effects on valuable freshwater fisheries. By integrating biological, hydrological, and climate data, DEWS provide real-time drought forecasts and long-term insights into how water management impacts fish populations and freshwater habitats. This enables proactive decision-making to protect fish, water resources, and human communities. With the 2025 launch of Fish-Cast, a web-based data visualization and decision-making platform, DEWS will help stakeholders across the western U.S. prepare for and respond to drought, strengthening resilience in freshwater ecosystems.
Drought Early Warning Systems for Freshwater Ecosystems and Fisheries

Extreme droughts are becoming more frequent and severe, posing a significant threat to freshwater ecosystems and the critical services they provide. Drought conditions reduce streamflows, increase water temperatures, and can put immense stress on fish populations, particularly cold-water species like trout. These impacts can lead to declines in trout production and survival, affecting not only the health of the ecosystem but also the economic value of recreational fisheries. As climate change intensifies, freshwater ecosystems face even greater vulnerability, with far-reaching consequences for biodiversity, ecological health, and economies.
To address these challenges, scientists at the U.S. Geological Survey (USGS) Northern Rocky Mountain Science Center (NOROCK) and Montana State University are developing Drought Early Warning Systems (DEWS) to help state, federal, and tribal resource managers better understand and manage drought risks to cold-water fisheries. By combining biological, hydrological, and climate data, these systems offer a comprehensive view of how drought impacts freshwater ecosystems, particularly trout habitats.
How DEWS Help Manage Drought Risks
DEWS are designed to predict drought impacts on fish populations, allowing resource managers to make proactive decisions to protect freshwater ecosystems. These systems provide:
- Seasonal Outlooks (1-3 months): Short-term forecasts of drought risk on streamflow and fish populations to help prepare for immediate drought impacts on freshwater fisheries.
- Long-Lead Forecasts (1-3 years): Long-lead forecasts of fish abundance to guide planning and adaptive management.
- Streamflow Effects on Fish Production: Long-term insights into how changes in streamflow affect the production of trout fisheries.
With these tools, managers can better anticipate drought impacts on valuable cold-water fisheries, improve drought resilience, and protect both ecological health and local economies that depend on healthy fisheries.

Key Objectives of the Drought Early Warning Systems
The DEWS initiative aims to achieve the following:
- Quantify Drought Impacts on Trout Populations: Analyze long-term fisheries and climate data to understand how drought affects trout recruitment, survival, and production.
- Create Real-Time Forecasting Tools: Develop models that predict fish population vulnerability and management targets based on streamflow and climate forecasts, water quality, and fish abundance.
- Build Streamflow-Fish Production Rule Curves: Build river-specific relationships of the value of streamflow to production of valuable fisheries. These empirical relationships will help managers with long-term planning and decision-making around streamflow management and fish production.
- Develop Decision-Support Tools: Develop user-friendly tools and data visualizations to help managers and the public understand, assess, and mitigate drought risks, ensuring sustainable fisheries.
Empowering Stakeholders with Data and Decision Tools

This project is creating the first regional drought early warning systems for cold-water fisheries across the western U.S. Initially focused on Montana’s famous “blue-ribbon” trout rivers, the project has expanded to the upper Snake River system in Wyoming and Idaho, in collaboration with a broad range of partners. This initiative will help resource managers, stakeholders, and communities adaptively manage the impacts of drought and climate change on diverse freshwater ecosystems.
A key component of the project is Fish-Cast, an integrated web tool designed for data sharing and communication among state, federal, tribal, and nonprofit partners. Set for release in Spring 2025, Fish-Cast will provide a centralized platform for “real-time” drought-related data and enhance public awareness, enabling informed decision-making during drought events.
Supporting Sustainable Freshwater Ecosystems
This project aligns with the Department of the Interior's goals to enhance understanding of how extreme droughts impact both freshwater ecosystems and the people who depend on them. By providing coordinated hydrological and biological data, forecasts, and decision-support tools, the initiative aims to improve drought planning, communication, and resilience for freshwater ecosystems across the United States.
The strength of this work lies in its integrated approach and proactive decision-making tools for water and fisheries management. By balancing the needs of human, agricultural, and ecological systems, the DEWS project ensures the long-term sustainability and resilience of our nation’s freshwater resources.
Through this collaborative effort, DEWS will help protect freshwater ecosystems, support local economies, and provide science-based tools for adaptive management in the face of increasing drought risks.
This project has been funded by the National Oceanic and Atmospheric Administration's National Integrated Drought Information System (NIDIS) and the USGS Ecosystems Mission Area.
Socioeconomic resilience to climatic extremes in a freshwater fishery
An integrated framework for ecological drought across riverscapes of North America
As droughts become more frequent and severe, freshwater ecosystems and the valuable fisheries they support face increasing challenges. Drought reduces streamflows, raises water temperatures, and stresses fish populations, particularly cold-water species like trout. These impacts can lead to declines in trout populations, threatening biodiversity, ecosystem health, and local economies. To address these threats, scientists at the USGS Northern Rocky Mountain Science Center and Montana State University are developing Drought Early Warning Systems (DEWS) to help resource managers better understand and manage drought effects on valuable freshwater fisheries. By integrating biological, hydrological, and climate data, DEWS provide real-time drought forecasts and long-term insights into how water management impacts fish populations and freshwater habitats. This enables proactive decision-making to protect fish, water resources, and human communities. With the 2025 launch of Fish-Cast, a web-based data visualization and decision-making platform, DEWS will help stakeholders across the western U.S. prepare for and respond to drought, strengthening resilience in freshwater ecosystems.
Drought Early Warning Systems for Freshwater Ecosystems and Fisheries

Extreme droughts are becoming more frequent and severe, posing a significant threat to freshwater ecosystems and the critical services they provide. Drought conditions reduce streamflows, increase water temperatures, and can put immense stress on fish populations, particularly cold-water species like trout. These impacts can lead to declines in trout production and survival, affecting not only the health of the ecosystem but also the economic value of recreational fisheries. As climate change intensifies, freshwater ecosystems face even greater vulnerability, with far-reaching consequences for biodiversity, ecological health, and economies.
To address these challenges, scientists at the U.S. Geological Survey (USGS) Northern Rocky Mountain Science Center (NOROCK) and Montana State University are developing Drought Early Warning Systems (DEWS) to help state, federal, and tribal resource managers better understand and manage drought risks to cold-water fisheries. By combining biological, hydrological, and climate data, these systems offer a comprehensive view of how drought impacts freshwater ecosystems, particularly trout habitats.
How DEWS Help Manage Drought Risks
DEWS are designed to predict drought impacts on fish populations, allowing resource managers to make proactive decisions to protect freshwater ecosystems. These systems provide:
- Seasonal Outlooks (1-3 months): Short-term forecasts of drought risk on streamflow and fish populations to help prepare for immediate drought impacts on freshwater fisheries.
- Long-Lead Forecasts (1-3 years): Long-lead forecasts of fish abundance to guide planning and adaptive management.
- Streamflow Effects on Fish Production: Long-term insights into how changes in streamflow affect the production of trout fisheries.
With these tools, managers can better anticipate drought impacts on valuable cold-water fisheries, improve drought resilience, and protect both ecological health and local economies that depend on healthy fisheries.

Key Objectives of the Drought Early Warning Systems
The DEWS initiative aims to achieve the following:
- Quantify Drought Impacts on Trout Populations: Analyze long-term fisheries and climate data to understand how drought affects trout recruitment, survival, and production.
- Create Real-Time Forecasting Tools: Develop models that predict fish population vulnerability and management targets based on streamflow and climate forecasts, water quality, and fish abundance.
- Build Streamflow-Fish Production Rule Curves: Build river-specific relationships of the value of streamflow to production of valuable fisheries. These empirical relationships will help managers with long-term planning and decision-making around streamflow management and fish production.
- Develop Decision-Support Tools: Develop user-friendly tools and data visualizations to help managers and the public understand, assess, and mitigate drought risks, ensuring sustainable fisheries.
Empowering Stakeholders with Data and Decision Tools

This project is creating the first regional drought early warning systems for cold-water fisheries across the western U.S. Initially focused on Montana’s famous “blue-ribbon” trout rivers, the project has expanded to the upper Snake River system in Wyoming and Idaho, in collaboration with a broad range of partners. This initiative will help resource managers, stakeholders, and communities adaptively manage the impacts of drought and climate change on diverse freshwater ecosystems.
A key component of the project is Fish-Cast, an integrated web tool designed for data sharing and communication among state, federal, tribal, and nonprofit partners. Set for release in Spring 2025, Fish-Cast will provide a centralized platform for “real-time” drought-related data and enhance public awareness, enabling informed decision-making during drought events.
Supporting Sustainable Freshwater Ecosystems
This project aligns with the Department of the Interior's goals to enhance understanding of how extreme droughts impact both freshwater ecosystems and the people who depend on them. By providing coordinated hydrological and biological data, forecasts, and decision-support tools, the initiative aims to improve drought planning, communication, and resilience for freshwater ecosystems across the United States.
The strength of this work lies in its integrated approach and proactive decision-making tools for water and fisheries management. By balancing the needs of human, agricultural, and ecological systems, the DEWS project ensures the long-term sustainability and resilience of our nation’s freshwater resources.
Through this collaborative effort, DEWS will help protect freshwater ecosystems, support local economies, and provide science-based tools for adaptive management in the face of increasing drought risks.
This project has been funded by the National Oceanic and Atmospheric Administration's National Integrated Drought Information System (NIDIS) and the USGS Ecosystems Mission Area.