Integrated Water Science Basins: Willamette River
USGS Selects Willamette River Basin as Fourth Integrated Water Science Basin
The Willamette River Basin is: rocky mountain stream headwaters
The Willamette River Basin is: regulated below-dam rivers
The Willamette River Basin is: fertile agricultural lands
The Willamette River Basin is: populous urban areas
The Willamette River Basin reflects the conflicting water demands between humans and ecosystems—particularly salmon— and the challenge resource managers face throughout the Pacific Northwest.
Key Messages
- In 2022, the USGS selected the Willamette River Basin (WRB) as the fourth of up to ten planned Integrated Water Science (IWS) basins. The Willamette River Basin was chosen because it represents many of the challenges faced by conflicting water demands between humans and ecosystems in the Pacific Northwest.
- The WRB IWS effort will span 10 years, and is divided into two phases:
- Phase 1 (2022-2026) will focus on understanding streamflow and stream temperature in salmon-bearing streams to inform current and future water availability for human needs (such as irrigation and public water supply) and fish habitats (particularly ESA-listed spring Chinook Salmon).
- Phase 2 (2027-2031) will produce a basin-wide assessment of groundwater and surface-water quantity and quality to better understand and predict water availability for a range of human and ecosystem needs now and in the future.
About the Willamette River Basin IWS
The Willamette River Basin (WRB) is home to 70 percent of Oregon’s population and most of its major cities. The WRB includes rural, urban, forested, and agricultural lands and its sub-basins are hydrologically and geologically diverse. Streamflow and fish passage in the Willamette River and its tributaries are influenced by large and small dams, including 19 large reservoirs that support human-based activities such as flood protection, water storage, recreation, and/or hydropower. WRB water is the source of drinking water for two million people, irrigation for agriculture throughout the valley, and habitat for 34 native fish species. Of these species, spring Chinook Salmon, winter steelhead, and Bull Trout are federally listed species and Pacific Lamprey are a culturally important species for Native American Tribes in the region. These species rely on habitat in the WRB for spawning, rearing, and migration.
The physical and human geographies of the WRB are interwoven. Both people and fish rely upon water for livelihoods, while facing water-related challenges from drought, floods and other pressures. Natural hazards like floods, fires, and landslides can threaten human lives and critical infrastructure, but in some cases can also create and maintain diverse river habitats. Pollution and land-use change can affect the health and resiliency of its natural systems and fish species, likewise the network of dams and flow regulation impedes fish passage and alters stream habitats.
The balance of human and ecosystem needs for water is an ongoing and increasing challenge for resource management across the basin. Human water demands peak in summer and can conflict with fish habitat needs. For example, baseflows in some locations and years are insufficient to meet authorized withdrawals, and water temperatures can in places exceed harmful and lethal thresholds for spring Chinook Salmon and winter steelhead, which are both listed as Threatened on the Endangered Species Act (ESA).
The Integrated Water Science (IWS) effort selects nationally representative basins for an intensive 10-year study to better understand water availability and resource challenges in a wide range of environmental, hydrologic, and landscape settings and human stressors. The water availability studies produced by the WRB IWS aim to yield insights that are useful to local water management decisions and planning efforts. The Willamette River Basin also shares many similarities with other large, regulated river basins in the U.S., and the models and analytical frameworks produced by the WRB IWS are intended to be useful and transferable to other river basins.
IWS Programs & Phases
The Willamette IWS is divided into two phases, which will each address different types and scales of water availability issues. Each phase will entail new data collection, analyses, and modeling to address issues pertinent to local water management decisions while developing transferable tools that can be applied to other large river basins.
Phase 1 (2022-2026) will focus on understanding streamflow and stream temperature in salmon-bearing streams of the Willamette Basin to understand current and future water availability for human needs (such as irrigation and public water supply) and fish habitats (particularly ESA-listed spring Chinook Salmon). Phase 1 begins in the fall of 2023 and extends through the fall of 2026.
Phase 2 (2027-2031) will entail a basin-wide assessment to understand quantity and quality of groundwater and surface water, both now and in the future, and water availability for a broad range of human and ecosystem needs. Phase 2 begins in the fall of 2026 and extends through the fall of 2031.
Timeline of activities
IWS activities are accomplished primarily through three USGS Water Resources Mission Area science programs—the Integrated Water Availability Assessments (IWAAs) program, the Next Generation Water Observing System (NGWOS) program, and the Integrated Water Prediction (IWP) program, which becomes more active in the later years. Together, they support the national IWS Priorities:
- Enhanced water monitoring, mapping, research & development of new instrumentation for water measurements and improving the delivery of water data
- Analyses and research studies to understand water availability and trends over time
- State-of-the-art water-availability models
In the Willamette River Basin, IWS activities will follow the timeline below:
IWAAs Phase 1 (2022-2026): Focus study on surface water for human uses and salmon habitats
Beginning fall 2023, the Willamette IWAAs program is evaluating surface water availability for human and fish habitat needs. The study goals and approaches are still in development and will be refined with stakeholder input, but will likely include the elements described below.
Phase 1 goal: Predict patterns of surface water available for human uses and salmon habitats, now and in the future
Phase 1 objectives:
- Understand how streamflow and water temperature vary over time and space across the basin
- Assess the human and natural factors that influence variation in streamflow and water temperature
- Examine past extreme hydroclimatic events and associated hydrologic and thermal responses
- Predict hydrologic and thermal responses to future hydroclimatic variability
- Assess implications of hydrologic and thermal variability for surface water available for water withdrawals (such as irrigation and public water supply) and fish habitats (primarily ESA-listed spring Chinook Salmon)
Phase 1 activities:
- Produce an assessment of surface water availability focused on surface water withdrawals to support irrigation and public water supply
- Produce an assessment of water availability focused on understanding physical habitats for ESA-listed spring Chinook Salmon. This assessment will consider all life stages that occur within the stream corridors of the Willamette River Basin and explore spring, summer, and early fall periods with particular emphasis on low-flow or extremely warm periods
- Produce an integrated assessment of surface water availability for human uses and spring Chinook Salmon and implications for water management
IWAAs Phase 2 (2027-2031): Comprehensive basin-wide study of water quantity, quality for human and ecological needs
Beginning in fall of 2026, the Willamette IWAAs will begin a five-year study of basin-wide water availability for a wide range of human and ecosystem needs. As part of this effort, the USGS will develop a series of integrated groundwater, surface-water and water-quality models, considering scenarios that represent current and future hydroclimatic, socioeconomic, and water management conditions. The exact goals and study approaches for Phase 2 are in the early stages of development, with an overarching vision of developing models that can a) inform local water management questions, and b) provide a foundation for future refinement as new data becomes available and management questions evolve. Moreover, the modeling framework applied in the Willamette Basin is intended to be transferable to other large river basins with similar hydrologic and management conditions.
NGWOS (2022-2026): Characterizing important habitat corridors through the development of next generation stream observation networks
In 2023-2024, data collection and research and development through NGWOS focuses on new streamflow and water temperature monitoring as well as new geospatial mapping to characterize water temperature, channel substrates and river bathymetry. This mapping is focused on small, unregulated stream reaches of the Cascades, including many above-dam river corridors that were historically or are presently used by spring Chinook salmon for spawning, rearing and migration. Not only will these new datasets address critical knowledge gaps in important, under-studied stream corridors, but they also inform the IWAAs Phase 1 study.
Integral to this effort is developing new mapping capabilities to conduct high-resolution river surveys from variety of airborne, satellite and boat-based platforms and fixed cameras. This effort includes developing new and efficient workflows to process these data. Likewise, our expanded gaging program includes “tiers” of in-situ data collection that complement the spatially-continuous datasets and provide a comprehensive view of the riverscape for hundreds of miles of rugged, remote salmon-bearing streams. Altogether, these efforts yield critical new insights for Willamette Basin river corridors, as well as affordable tools for tracking future changes and transferable capabilities applicable to other basins.
New NGWOS data collection and mapping includes:
- New water quality and quantity monitoring to increase data coverage in the Willamette River Basin and develop new methods; this includes adding water temperature sensors to existing streamflow gages throughout the basin and adding new gages.
- New data collection to characterize river bathymetry, substrates, and channel morphology and develop cost efficient and transferable techniques. Initial efforts are assessing spawning habitat for spring Chinook Salmon in above-dam reaches in the Santiam River Basin. Teams are Additional efforts may expand to other Cascade and Coast Range sub-basins in the future.
- In 2023-24, USGS will collect over 125 miles of topographic-bathymetric on rivers important to spring Chinook Salmon. Rivers covered include reaches above and below high-head dams in the Santiam, McKenzie, Clackamas, and Middle Fork Willamette River basins. These data are critical for modeling flood hazards and evaluating water availability for human uses (such as public water supply and irrigation) and fish habitat. This large data acquisition was made possible by close collaboration between the USGS Oregon Water Science Center, USGS 3D Elevation Program, and U.S. Army Corps of Engineers.
- Compilation, visualization, and modeling of historical and current water temperature data for the Willamette River Basin in coordination with partners, including the Oregon Department of Environmental Quality, Oregon Department of Fish and Wildlife, NOAA Fisheries, NV5 , and U.S. Forest Service.
- A multi-scale characterization of stream temperature for the Santiam River Basin. Thermal infrared imagery collection is planned for major salmon-bearing rivers upstream of dams in the North Santiam, Middle Santiam, and South Santiam Rivers and Quartzville Creek.
NGWOS 2027-2031 Data Collection: Broader suite of data collection, research, and development
In the future, NGWOS will cover a wide range of data collection that supports and improves the assessment, management, and prediction of water resources in the Willamette Basin. This effort supports partner information needs and relies on their input to help us design the NGWOS network. We plan to address monitoring gaps in the basin by adding additional monitoring locations to the NGWOS network, testing new instrumentation and updating existing equipment, sample lists, and methods.
Below are other science projects associated with the Willamette Integrated Water Science Basin.
Integrated Water Science (IWS) Basins
Integrated Water Availability Assessments
Next Generation Water Observing System (NGWOS)
Integrated Water Prediction (IWP)
The Willamette River Basin reflects the conflicting water demands between humans and ecosystems—particularly salmon— and the challenge resource managers face throughout the Pacific Northwest.
Key Messages
- In 2022, the USGS selected the Willamette River Basin (WRB) as the fourth of up to ten planned Integrated Water Science (IWS) basins. The Willamette River Basin was chosen because it represents many of the challenges faced by conflicting water demands between humans and ecosystems in the Pacific Northwest.
- The WRB IWS effort will span 10 years, and is divided into two phases:
- Phase 1 (2022-2026) will focus on understanding streamflow and stream temperature in salmon-bearing streams to inform current and future water availability for human needs (such as irrigation and public water supply) and fish habitats (particularly ESA-listed spring Chinook Salmon).
- Phase 2 (2027-2031) will produce a basin-wide assessment of groundwater and surface-water quantity and quality to better understand and predict water availability for a range of human and ecosystem needs now and in the future.
About the Willamette River Basin IWS
The Willamette River Basin (WRB) is home to 70 percent of Oregon’s population and most of its major cities. The WRB includes rural, urban, forested, and agricultural lands and its sub-basins are hydrologically and geologically diverse. Streamflow and fish passage in the Willamette River and its tributaries are influenced by large and small dams, including 19 large reservoirs that support human-based activities such as flood protection, water storage, recreation, and/or hydropower. WRB water is the source of drinking water for two million people, irrigation for agriculture throughout the valley, and habitat for 34 native fish species. Of these species, spring Chinook Salmon, winter steelhead, and Bull Trout are federally listed species and Pacific Lamprey are a culturally important species for Native American Tribes in the region. These species rely on habitat in the WRB for spawning, rearing, and migration.
The physical and human geographies of the WRB are interwoven. Both people and fish rely upon water for livelihoods, while facing water-related challenges from drought, floods and other pressures. Natural hazards like floods, fires, and landslides can threaten human lives and critical infrastructure, but in some cases can also create and maintain diverse river habitats. Pollution and land-use change can affect the health and resiliency of its natural systems and fish species, likewise the network of dams and flow regulation impedes fish passage and alters stream habitats.
The balance of human and ecosystem needs for water is an ongoing and increasing challenge for resource management across the basin. Human water demands peak in summer and can conflict with fish habitat needs. For example, baseflows in some locations and years are insufficient to meet authorized withdrawals, and water temperatures can in places exceed harmful and lethal thresholds for spring Chinook Salmon and winter steelhead, which are both listed as Threatened on the Endangered Species Act (ESA).
The Integrated Water Science (IWS) effort selects nationally representative basins for an intensive 10-year study to better understand water availability and resource challenges in a wide range of environmental, hydrologic, and landscape settings and human stressors. The water availability studies produced by the WRB IWS aim to yield insights that are useful to local water management decisions and planning efforts. The Willamette River Basin also shares many similarities with other large, regulated river basins in the U.S., and the models and analytical frameworks produced by the WRB IWS are intended to be useful and transferable to other river basins.
IWS Programs & Phases
The Willamette IWS is divided into two phases, which will each address different types and scales of water availability issues. Each phase will entail new data collection, analyses, and modeling to address issues pertinent to local water management decisions while developing transferable tools that can be applied to other large river basins.
Phase 1 (2022-2026) will focus on understanding streamflow and stream temperature in salmon-bearing streams of the Willamette Basin to understand current and future water availability for human needs (such as irrigation and public water supply) and fish habitats (particularly ESA-listed spring Chinook Salmon). Phase 1 begins in the fall of 2023 and extends through the fall of 2026.
Phase 2 (2027-2031) will entail a basin-wide assessment to understand quantity and quality of groundwater and surface water, both now and in the future, and water availability for a broad range of human and ecosystem needs. Phase 2 begins in the fall of 2026 and extends through the fall of 2031.
Timeline of activities
IWS activities are accomplished primarily through three USGS Water Resources Mission Area science programs—the Integrated Water Availability Assessments (IWAAs) program, the Next Generation Water Observing System (NGWOS) program, and the Integrated Water Prediction (IWP) program, which becomes more active in the later years. Together, they support the national IWS Priorities:
- Enhanced water monitoring, mapping, research & development of new instrumentation for water measurements and improving the delivery of water data
- Analyses and research studies to understand water availability and trends over time
- State-of-the-art water-availability models
In the Willamette River Basin, IWS activities will follow the timeline below:
IWAAs Phase 1 (2022-2026): Focus study on surface water for human uses and salmon habitats
Beginning fall 2023, the Willamette IWAAs program is evaluating surface water availability for human and fish habitat needs. The study goals and approaches are still in development and will be refined with stakeholder input, but will likely include the elements described below.
Phase 1 goal: Predict patterns of surface water available for human uses and salmon habitats, now and in the future
Phase 1 objectives:
- Understand how streamflow and water temperature vary over time and space across the basin
- Assess the human and natural factors that influence variation in streamflow and water temperature
- Examine past extreme hydroclimatic events and associated hydrologic and thermal responses
- Predict hydrologic and thermal responses to future hydroclimatic variability
- Assess implications of hydrologic and thermal variability for surface water available for water withdrawals (such as irrigation and public water supply) and fish habitats (primarily ESA-listed spring Chinook Salmon)
Phase 1 activities:
- Produce an assessment of surface water availability focused on surface water withdrawals to support irrigation and public water supply
- Produce an assessment of water availability focused on understanding physical habitats for ESA-listed spring Chinook Salmon. This assessment will consider all life stages that occur within the stream corridors of the Willamette River Basin and explore spring, summer, and early fall periods with particular emphasis on low-flow or extremely warm periods
- Produce an integrated assessment of surface water availability for human uses and spring Chinook Salmon and implications for water management
IWAAs Phase 2 (2027-2031): Comprehensive basin-wide study of water quantity, quality for human and ecological needs
Beginning in fall of 2026, the Willamette IWAAs will begin a five-year study of basin-wide water availability for a wide range of human and ecosystem needs. As part of this effort, the USGS will develop a series of integrated groundwater, surface-water and water-quality models, considering scenarios that represent current and future hydroclimatic, socioeconomic, and water management conditions. The exact goals and study approaches for Phase 2 are in the early stages of development, with an overarching vision of developing models that can a) inform local water management questions, and b) provide a foundation for future refinement as new data becomes available and management questions evolve. Moreover, the modeling framework applied in the Willamette Basin is intended to be transferable to other large river basins with similar hydrologic and management conditions.
NGWOS (2022-2026): Characterizing important habitat corridors through the development of next generation stream observation networks
In 2023-2024, data collection and research and development through NGWOS focuses on new streamflow and water temperature monitoring as well as new geospatial mapping to characterize water temperature, channel substrates and river bathymetry. This mapping is focused on small, unregulated stream reaches of the Cascades, including many above-dam river corridors that were historically or are presently used by spring Chinook salmon for spawning, rearing and migration. Not only will these new datasets address critical knowledge gaps in important, under-studied stream corridors, but they also inform the IWAAs Phase 1 study.
Integral to this effort is developing new mapping capabilities to conduct high-resolution river surveys from variety of airborne, satellite and boat-based platforms and fixed cameras. This effort includes developing new and efficient workflows to process these data. Likewise, our expanded gaging program includes “tiers” of in-situ data collection that complement the spatially-continuous datasets and provide a comprehensive view of the riverscape for hundreds of miles of rugged, remote salmon-bearing streams. Altogether, these efforts yield critical new insights for Willamette Basin river corridors, as well as affordable tools for tracking future changes and transferable capabilities applicable to other basins.
New NGWOS data collection and mapping includes:
- New water quality and quantity monitoring to increase data coverage in the Willamette River Basin and develop new methods; this includes adding water temperature sensors to existing streamflow gages throughout the basin and adding new gages.
- New data collection to characterize river bathymetry, substrates, and channel morphology and develop cost efficient and transferable techniques. Initial efforts are assessing spawning habitat for spring Chinook Salmon in above-dam reaches in the Santiam River Basin. Teams are Additional efforts may expand to other Cascade and Coast Range sub-basins in the future.
- In 2023-24, USGS will collect over 125 miles of topographic-bathymetric on rivers important to spring Chinook Salmon. Rivers covered include reaches above and below high-head dams in the Santiam, McKenzie, Clackamas, and Middle Fork Willamette River basins. These data are critical for modeling flood hazards and evaluating water availability for human uses (such as public water supply and irrigation) and fish habitat. This large data acquisition was made possible by close collaboration between the USGS Oregon Water Science Center, USGS 3D Elevation Program, and U.S. Army Corps of Engineers.
- Compilation, visualization, and modeling of historical and current water temperature data for the Willamette River Basin in coordination with partners, including the Oregon Department of Environmental Quality, Oregon Department of Fish and Wildlife, NOAA Fisheries, NV5 , and U.S. Forest Service.
- A multi-scale characterization of stream temperature for the Santiam River Basin. Thermal infrared imagery collection is planned for major salmon-bearing rivers upstream of dams in the North Santiam, Middle Santiam, and South Santiam Rivers and Quartzville Creek.
NGWOS 2027-2031 Data Collection: Broader suite of data collection, research, and development
In the future, NGWOS will cover a wide range of data collection that supports and improves the assessment, management, and prediction of water resources in the Willamette Basin. This effort supports partner information needs and relies on their input to help us design the NGWOS network. We plan to address monitoring gaps in the basin by adding additional monitoring locations to the NGWOS network, testing new instrumentation and updating existing equipment, sample lists, and methods.
Below are other science projects associated with the Willamette Integrated Water Science Basin.