Predictions of Global Warming Impacts in the Upper Willamette River Basin
Preparing for Climate Change in the Upper Willamette River Basin of Western Oregon
- Rising Temperatures: Within the Basin, annual average temperatures are likely to increase from 2 to 4ºF (1 to 2ºC) by 2040 and an additional 6 to 8ºF (3 to 4ºC) by 2080. More worrisome are summer temperatures, which are likely to rise 4 to 6ºF by 2040 and 8 to 13ºF by 2080.
- Wildfires and Flooding: Most of the basin (90%) is covered by forestland, 2 million acres of which is already at a high risk of wildfire. Heightened temperatures increase the likelihood of wildfires and flooding, both of which threaten buildings, transportation systems, and other public infrastructure. Especially vulnerable areas fall within the wildland-urban interface and floodplains. Of the 47,600 acres of land that are on taxable lots, nearly 33,450 acres are in the floodplain.
- Vulnerability of Local Species: Some local species will be put in an especially risky position, including those at high elevations (alpine and sub-alpine species), species dependent on old-growth forests (e.g. Northern Spotted Owl), moisture dependent species (e.g. waterbirds), and already rare/declining species. Additional stress may come from invasive species and refugees, who come to the Basin from areas with larger climactic problems.
- Snowpack and Water Supplies: Compared to historic levels, snowpack across the Pacific Northwest will likely decline 60% by 2040 and 80-90% by 2095. Less snowpack, in combination with summer drought and evapotranspiration, may result in water shortages. Even the McKenzie River, which is vital to Eugene municipal water supply in the summer months, is projected to experience a loss of summer stream-flows.
- Economic Impacts: The economy of the Upper Willamette River Basin (including manufacturing, services, agriculture, forestry, and tourism) is highly dependent on stored water for hydroelectricity, irrigation, and municipal water supply. It also depends on readily available local, regional, and national transportation. Climate change threatens the Basin’s water supply. In addition, road, air, and rail transportation are likely to face disruptions due to increased storm events (locally and elsewhere), flooding, and wildfires.
- Public Health: Rising summer temperatures will increase the incidences of heat-related illnesses, such as heat stroke and exhaustion. These illnesses are likely to be exacerbated by the fact that many homes in the Upper Willamette River Basin lack air conditioning. Warmer waters and increased flooding will also increase the incidence of West Nile virus and malaria, both of which were endemic in the Basin during the 19th century.
