Impact on the Columbia River of an outburst of Spirit Lake

Water-Resources Investigations Report 85-4054



A one-dimensional sediment-transport computer model was used to study the effects of an outburst of Spirit Lake on the Columbia River. According to the model, flood sediment discharge to the Columbia from the Cowlitz would form a blockage to a height of 44 feet above the current streambed of the Columbia River, corresponding to a new streambed elevation of -3 feet, that would impound the waters of the Columbia River. For an average flow of 233,000 cubic feet in that river, water surface elevations would continue to increase for 16 days after the blockage had been formed. The river elevation at the Trojan nuclear power plant, 5 miles upstream of the Cowlitz River, would rise to 32 feet, compared to a critical elevation of 45 feet, above which the plant would be flooded. For comparison, the Columbia River at average flow without the blockage has an elevation at this location of 6 feet. Correspondingly high water surface elevations would occur along the river to Bonneville Dam , with that at Portland, Oregon, for example, rising also to 32 feet, compared to 10 feet without the blockage. (USGS)
Publication type Report
Publication Subtype USGS Numbered Series
Title Impact on the Columbia River of an outburst of Spirit Lake
Series title Water-Resources Investigations Report
Series number 85-4054
DOI 10.3133/wri854054
Year Published 1985
Language English
Publisher U.S. Geological Survey,
Publisher location Reston, VA
Contributing office(s) Volcano Hazards Program
Description 60 p.
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