Climate Change Scenarios
Climate Change Streamflow Scenario Tool
ARCHIVE: This tool was replaced in spring 2009 with an expanded set of streamflow locations (271 sites) and modeled variables (in addition to streamflow). This page is currently not being supported.
- Alan Hamlet, CIG and UW Civil Engineering (contact person)
- Amy Snover, CIG
- Dennis Lettenmaier, CIG and UW Civil Engineering
Climate change streamflow scenarios are provided to support simple and inexpensive evaluation of a water resource system’s vulnerability to climate change. The streamflow scenarios can be directly incorporated into existing planning methods (such as critical period analysis) in place of the historic streamflow record.
The scenarios are currently available at 16 locations in the Columbia River basin (Figure 1). For each location, we provide 40 year monthly time-step streamflow scenarios for the 2020s and for the 2040s as well as simulated historical streamflow for water years 1950-1989. These flow records represent what historical observed (naturalized) flows would be if the average climate of the Pacific Northwest (PNW) changed as projected by global climate models.
click image to visit streamflow scenarios page
Figure 1 Streamflow scenarios are currently available for 16 sites in the Columbia River Basin. For a list of these sites and data links, please visit the streamflow scenarios page.
These streamflow scenarios allow planners to compare, water year by water year, the performance of water resources planning alternatives for the historic record and various climate change scenarios. Using these scenarios, planners can explore questions like:
- What would water year X (e.g., 1933, 1954) look like under a global warming scenario (i.e., in the decade of the 2020s or the 2040s)?
- How would climate change affect the reliability and vulnerability of my system?
- How could operations be changed to cope with these changes?
This tool has been described in a recent paper in the Bulletin of the American Meteorological Society (Snover et al. 2003). The number of regional climate change scenarios, streamflow locations, and years for which data are provided will be expanded in ongoing work.
Types of Streamflow
Hydrologists talk about several different types of streamflow: observed, naturalized, modified and regulated flows.
- Naturalized flows represent the flow pattern that would be present in the absence of any human modification (e.g., dams/reservoirs) of the river system.
- Modified flows are naturalized flows minus consumptive losses for irrigation and municipal and industrial use.
- In a managed river system, regulated flows are the flows that are observed.