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Sediment delivery in a changing climate

Posted date: January 23, 2015
Publication Year: 
2014
Authors: Buffington, John M.; Luce, Charles H.;
Document type: Briefing Papers

Description

The delivery and transport of sediment through mountain rivers affects aquatic habitat and water resource infrastructure. While climate change is widely expected to produce significant changes in hydrology and stream temperature, the effects of climate change on sediment yield have received less attention. In the northern Rocky Mountains, climate change is expected to increase sediment yield primarily through changes in temperature and hydrology that promote vegetation disturbances (i.e., wildfire, insect or pathogen outbreak, drought-related die off).

Key Findings:

  • Sediment delivery in the Idaho batholith is dominated by episodic pluses associated with post-fire thunder storms.
  • Projected climatic trends, increased frequency of wildfires, and changing hydrology are likely to increase sediment yields.
  • Sediment delivery from fire-induced debris flows is greater in magnitude, but lower in frequency compared to the chronic supply from roads.
  • Road restoration is expected to provide relatively minor reductions in sediment yield, but may locally benefit aquatic ecosystems by reducing detrimental fine sediment input.
  • Episodic debris flows are impractical to manage and the dynamic response to such events may help to maintain more diverse and resilient ecosystems.