Pacific Northwest Region

Columbia River Basin Impacts Assessment Overview

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A primary focus of the Assessment is to generate future climate change flow at more than 300 locations across the Columbia River Basin (Basin) and evaluated the potential impact of those flows at specific sub-basins within the Basin. These future climate change flows will be generated using the 1/16th degree Variable Infiltration Capacity hydrologic model using the International Panel on Climate Change Coupled Model Intercomparison Program Phase 5 (CMIP5) climate change projections.

With those flows, Reclamation will conduct more detailed analyses in the upper Snake River Basin (from the headwaters to Brownlee Reservoir including major tributaries) using the MODSIM-DSS model to evaluate how changes in water supply and demand will impact reservoir operations and environmental requirements. In addition, specific applications of the future climate change flow will be also used in hydraulic models that have been constructed for restoration efforts in the Grande Ronde basin (Oregon) and the Middle Fork John Day River (Oregon) basin.

These future climate change flows will be used to quantitatively evaluate the impacts associated with climate change as they relate to the mission of Reclamation. This will include risks to water supplies and any increase in the demand for water as a result of increasing temperatures and the reservoir evaporation rates for the Basin. The impacts of these changes will be analyzed on water delivery, power generation, ecological resources, flood control, and recreation at Reclamation facilities. To identify the risks and impacts to these components, the Assessment will use the best available science and climate information within a planning context at the reconnaissance level.

The potential impacts of future climate change flows on Reclamation’s engineering design and habitat restoration activities will be determined and compared with results obtained using stationarity. Stationarity assumes that climate doesn’t change in the future. The assumption of stationarity has been a standard method for generating river flow data for decades. Flow impacted by climate change (termed non-stationarity) impacts will be quantified for use in determining the next steps of incorporating climate change flow into these program areas.

Climate change information on the mainstem Columbia River will be summarized from the River Management Joint Operating Committee (RMJOC) Climate Change Study (2011). Because RMJOC Climate Change Study used IPCC CMIP3 climate change data, a comparison of the results from that effort and the Assessment will be made to identify any changes. These updated datasets will be available to our partners for future use in understanding impacts to power production, flooding, and other aspects of water resources on the mainstream.

Contact

Carri Hessman
Program Manager
(208) 378-5106
chessman@usbr.gov

Bureau of Reclamation
Pacific Northwest Regional Office
1150 North Curtis Road, Suite 100
Boise, Idaho 83706-1234