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Digital elevation models of upper North Fork Toutle River near Mount St. Helens, based on 2006-2014 airborne lidar surveys

April 11, 2019

The lateral blast, debris avalanche, and lahars of the May 18th, 1980, eruption of Mount St. Helens, Washington, dramatically altered the surrounding landscape. Lava domes were extruded during the subsequent eruptive periods of 1980-1986 and 2004-2008. Nearly four decades after the emplacement of the 1980 debris avalanche, high sediment production persists in the North Fork Toutle River basin, which drains the northern flank of the volcano. This high sediment production poses a risk of flooding to downstream communities along the Toutle and Cowlitz Rivers and of clogging the shipping channel of the Columbia River. Consequently, U.S. Army Corps of Engineers (USACE), under the direction of Congress, built a sediment retention structure on the North Fork Toutle River in 1989 to maintain an authorized level of flood protection. During 2006, 2010, 2011, 2012, 2013, and 2014, USACE contracted the acquisitions of six high-precision airborne lidar surveys of upper North Fork Toutle River valley near Mount St. Helens. All surveys used near infrared lasers except the 2014 topobathymetric lidar survey which used a green laser scanner. The U.S. Geological Survey (USGS) used classified returns and breaklines from these surveys to produce digital elevation models (DEMs) of the ground surface for each dataset, including beneath forest cover and shallow water surfaces. This USGS data release contains digital elevation data as a 3-foot resolution raster datasets (.tif files). This DEM can be used to develop sediment budgets and models of sediment erosion, transport, and deposition.

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