Water Resources

Climate change and peak flows: Knowledge-to-action to help managers address impacts on streamflow dynamics and aquatic habitat

Contact First Name: 
Gordon
Contact Last Name: 
Grant
Principal Investigator(s): 
Gordon Grant, Anne Nolin, Becky Flitcroft
Research Partners: 
Oregon State University
FS Research Station(s): 
Pacific Northwest Research Station
Summary: 

What will the rivers of the Pacific Northwest look like in the future? Will they be stable or unstable? Will they have salmon or other species? Will the waters be cold and clear or warm and muddy? These questions motivate our study of the effects of climate warming on streams draining the Cascade Mountains.

Previous studies have shown that snowpacks throughout the Cascades are highly vulnerable to warming temperatures, readily changing from snow to rain, and melting earlier. Less certain is how these changes are likely to affect streamflows, particularly in streams that derive much of their flow from deep groundwater and springs. These groundwater streams, which are currently characterized by very stable bed, banks, and vegetation, are particularly sensitive to increasing peak flows in the winter. We want to know how changing snowpacks and increased peak flows are likely to affect these channels, potentially changing their suitability as habitat for threatened species such as bull trout and spring Chinook. Results from our work, which include field and modeling components, will be used to guide management decisions affecting these streams: how dams are operated, whether water suppliers need to worry about turbidity, and how we should manage riparian vegetation.

Geographic Region: 
United States
Pacific Southwest Region (R5)
California
Pacific Northwest Region (R6)
Oregon
Washington
Project Status: 
Action
Record Entry Date: 
Tue, 09/23/2014

Coupling snowpack and groundwater dynamics to interpret historical streamflow trends in the western United States

Contact First Name: 
Gordon
Contact Last Name: 
Grant
Principal Investigator(s): 
Gordon Grant, Mohammad Safeeq
Research Partners: 
Oregon State University
FS Research Station(s): 
Pacific Northwest Research Station
Summary: 

A key challenge for resource and land managers is predicting the consequences of climate warming on streamflow and water resources. Over the last century in the western US, significant reductions in snowpack and earlier snowmelt have led to an increase in the fraction of annual streamflow during winter, and a decline in the summer. This study explores the relative roles of snowpack accumulation and melt, and landscape characteristics or 'drainage efficiency', in influencing streamflow. An analysis of streamflow during 1950-2010 for 81 watersheds across the western US indicates that summer streamflows in watersheds that drain slowly from deep groundwater and receive precipitation as snow are most sensitive to climate warming. During the spring, however, watersheds that drain rapidly and receive precipitation as snow are most sensitive to climate warming. Our results indicate that not all trends in the western US are associated with changes in snowpack dynamics; we observe declining streamflow in late fall and winter in rain-dominated watersheds as well. These empirical findings have implications for how streamflow sensitivity to warming is interpreted across broad regions.

Project Abstract: 

See more below

Research Results: 

Coupling snowpack and groundwater dynamics to interpret historical stream flow trends in the western United States - http://www.fsl.orst.edu/wpg/pubs/13_Safeeqetal_HP.pdf

Geographic Region: 
United States
Northern Region (R1)
Idaho
Montana
Intermountain Region (R4)
Idaho
Nevada
Utah
Pacific Southwest Region (R5)
California
Pacific Northwest Region (R6)
Oregon
Washington
Project Status: 
Complete
Record Entry Date: 
Tue, 09/23/2014

Evaluating landscape level sensitivity to changing peak and low streamflow regimes

Contact First Name: 
Gordon
Contact Last Name: 
Grant
Principal Investigator(s): 
Gordon Grant, Mohammad Safeeq, Brian Staab
Research Partners: 
Oregon State University, FS Region 6
FS Research Station(s): 
Pacific Northwest Research Station
Summary: 

Changes in timing and magnitudes of streamflows under climate change pose significant risks to ecosystems, infrastructure, and overall availability of water for human use. We have developed a spatial analysis that predicts how both peak (winter) and low (summer) streamflows are likely to change in the future for Oregon and Washington. This set of spatial tools gives land managers a full toolbox with which to anticipate and plan for streamflow changes on forest lands.

Project Abstract: 

See more below

Research Results: 

A geohydrologic framework for characterizing summer streamflow sensitivity to climate warming in the Pacific Northwest, USA - http://www.fsl.orst.edu/wpg/pubs/14_Safeeqetal_HESS_discussion.pdf

Geographic Region: 
United States
Pacific Northwest Region (R6)
Oregon
Washington
Project Status: 
Action
Record Entry Date: 
Tue, 09/23/2014

Watering the Forests for the Trees: an emerging priority for managing water in forest landscapes

Contact First Name: 
Gordon
Contact Last Name: 
Grant
Principal Investigator(s): 
Gordon Grant, Naomi Tague, Craig Allen
Research Partners: 
UC Santa Barbara, US Geological Survey
FS Research Station(s): 
Pacific Northwest Research Station
Summary: 

Water stress represents a common mechanism for many of the primary disturbances affecting forests, and forest management needs to explicitly address the very large physiological demands that vegetation has for water. This study demonstrates how state-of-science ecohydrologic models can be used to explore how different management strategies might improve forest health.

Project Abstract: 

Widespread threats to forests due to drought stress prompt re-thinking of priorities for water management on forest lands. In contrast to the widely held view that forest management should emphasize providing water for downstream uses, we argue that maintaining forest health in the face of environmental change may require focusing on the forests themselves and strategies to reduce their vulnerability to increasing water stress in the context of a changing climate. Management strategies would need to be tailored to specific landscapes but could include: a) thinning; 2) encouraging drought-tolerant species; 3) irrigation; and 4) strategies that make more water available to plants for transpiration. Hydrologic modeling reveals that specific management actions could reduce tree mortality due to drought stress. Adopting water conservation for vegetation as a priority for managing water on forest lands would represent a fundamental change in perspective and potentially involve tradeoffs with other downstream uses of water.

Research Results: 

Watering the Forests for the Trees: an emerging priority for managing water in forest landscapes - http://www.fsl.orst.edu/wpg/pubs/13_Granteal_WFFT.pdf

Geographic Region: 
United States
Alaska Region (R10)
Northern Region (R1)
Rocky Mountain Region (R2)
Southwestern Region (R3)
Intermountain Region (R4)
Pacific Southwest Region (R5)
Pacific Northwest Region (R6)
Southern Region (R8)
Eastern Region (R9)
Virgin Islands
Project Status: 
Complete
Record Entry Date: 
Tue, 09/23/2014

Climate change and future stream temperatures in the interior Columbia River Basin

Contact First Name: 
Steve
Contact Last Name: 
Wondzell
Principal Investigator(s): 
Steve Wondzell
FS Research Station(s): 
Pacific Northwest Research Station
Summary: 

Restoring riparian forests on streams where historic land uses have created open meadows could reduce maximum stream temperatures by as much as 7o C relative to current conditions, even under a future climate when air temperatures are 4o C warmer than today.

Project Abstract: 

Summer maximum stream temperatures are near thresholds of thermal tolerance for salmon and trout in many streams throughout the interior Columbia River Basin. Salmon and trout populations in many of these streams are severely depressed, resulting in efforts to restore stream and riparian habitat. Climate change raises serious questions about the long-term outcomes of restoration because projected warming could make many of these streams and rivers uninhabitable for salmon and trout within a few decades.

We used the mechanistic stream temperature model, HeatSource, to examine future changes in stream temperature on the upper Middle Fork John Day River. Our model scenarios examined: 1) a +4 oC increase in air temperature; 2) ±30% changes in stream discharge from both changes in irrigation withdrawals and climate-change related loss of winter snowpacks; and 3) four riparian vegetation scenarios: 3a) current conditions where effective stream shade averages 19%; 3b) a post-wild fire scenario with maximum vegetation height of 1 m and 10% canopy density resulting in 7% effective stream shade; 3c) an intermediate condition representing a young-open forest or tall-shrub dominated vegetation with trees or shrubs 10-m tall and with 30% canopy density resulting in 34% effective shade; and 3d) a restored riparian forest with trees 30-m high and canopy density of 50% resulting in 79% effective stream shade.

Our model results showed the composition and structure of riparian vegetation were the single biggest factor determining future stream temperatures. In contrast, changing air temperature or stream discharge had relatively small influence on future stream temperatures. The post-wildfire and the current-vegetation scenarios were warmer than today, but in both cases, effective shade was low, so the stream was sensitive to air temperature increases due to climate change. The intermediate restoration, simulating a young-open forest or a tall-shrub dominated riparian zone, was slightly cooler than today. The biggest change resulted from restoring the riparian forest which decreased summer maximum temperatures by ~ 7 oC.

Research Results: 

Manuscripts are in progress.

Geographic Region: 
United States
Northern Region (R1)
Montana
Pacific Northwest Region (R6)
Oregon
Washington
Project Status: 
Complete
Record Entry Date: 
Mon, 09/08/2014

NorEaST - Stream Temperature Web Portal

Overview & Applicability

Stream data are needed to enable managers to understand baseline conditions, historic trends, and potential impacts of climate change on stream temperature and flow, and in turn on aquatic species in freshwater ecosystems.

Summary: 

NorEaST is being developed to provide a coordinated, multi-agency regional web portal to compile, store, map, and distribute continuous stream temperature locations and data across the Northeastern U.S.

Assessing Local Urban Forest Carbon Storage, Sequestration and Effects on Emissions from Building Energy Use

Contact First Name: 
David
Contact Last Name: 
Nowak
Principal Investigator(s): 
David Nowak
FS Research Station(s): 
Northern Research Station
Summary: 

The i-Tree suite of models is designed to link research with local data on tree populations to assess the services and values provide by trees. The model is constantly being updated with new features and is being used globally. The model estimates numerous ecosystem services, disservices, and values, and includes estimates of tree carbon storage and annual sequestration, and their effects on building energy and consequent emissions from power plants. For more, please see the i-Tree tools page.

Geographic Region: 
United States
Project Status: 
Action
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