| The cataclysmic eruption of Mount St. Helens, in southwestern Washington, on May 18, 1980, produced devastating mudflows that delivered large quantities of debris to the lower reaches of the Cowlitz River and the Columbia River near Longview, Wash. To obtain information on the character of the "new" sediment and its disposition in the rivers, data were collected during a 9-day period in mid-August 1980. This report presents hydrologic data collected for the investigation and discusses the findings. The information pertains mainly to the particle-size distribution, shape factor, and specific gravity of bottom sediments, although some information is given on the disposition of suspended sediment; the results are based on limited data that were collected over a very short span of time. -- Hubbell, 1983 |
