High-Resolution Digital Elevation Model of Lower Cowlitz 
  and Toutle Rivers, Adjacent to Mount St. Helens, 
  Washington, Based on an Airborne Lidar Survey of October 
  2007

  By Adam R. Mosbrucker

  Prepared in cooperation with the U.S. Army Corps of 
  Engineers

  Data Series 936

  2015

  U.S. Department of the Interior
  U.S. Geological Survey


  Abstract:

  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. More than three decades after the 
  emplacement of the 1980 debris avalanche, high sediment 
  production persists in the Toutle River basin, which drains 
  the northern and western flanks of the volcano. Because 
  this sediment increases the risk of flooding to downstream 
  communities on the Toutle and lower Cowlitz Rivers, the 
  U.S. Army Corps of Engineers (USACE), under the direction 
  of Congress to maintain an authorized level of flood 
  protection, continues to monitor and mitigate excess 
  sediment in North and South Fork Toutle River basins to 
  help reduce this risk and to prevent sediment from clogging 
  the shipping channel of the Columbia River. From October 
  22-27, 2007, Watershed Sciences, Inc., under contract to 
  USACE, collected high-precision airborne lidar (light 
  detection and ranging) data that cover 273 square 
  kilometers (105 square miles) of lower Cowlitz and Toutle 
  River tributaries from the Columbia River at Kelso, 
  Washington, to upper North Fork Toutle River (below the 
  volcano's edifice), including lower South Fork Toutle 
  River. These data provide a digital dataset of the ground 
  surface, including beneath forest cover. Such remotely 
  sensed data can be used to develop sediment budgets and 
  models of sediment erosion, transport, and deposition. The 
  U.S. Geological Survey (USGS) used these lidar data to 
  develop digital elevation models (DEMs) of the study area. 
  DEMs are fundamental to monitoring natural hazards and 
  studying volcanic landforms, fluvial and glacial 
  geomorphology, and surface geology. Watershed Sciences, 
  Inc., provided files in the LASer (LAS) format containing 
  laser returns that had been filtered, classified, and 
  georeferenced. The USGS produced a hydro-flattened DEM from 
  ground-classified points at Castle and Coldwater Lakes. 
  Final results averaged about two laser last-return points 
  per square meter. As reported by Watershed Sciences, Inc., 
  vertical accuracy is 10 centimeters (cm) at the 95-percent 
  confidence interval on bare road surfaces; however, over 
  natural terrain, USGS found vertical accuracy to be 10-50 
  cm. This USGS data series contains the bare-earth lidar 
  data as 1- and 10-meter (m) resolution Esri grid files. 
  Digital-elevation data can be downloaded (1m_DEM.zip and 
  10m_DEM.zip), as well as a 1-m resolution hillshade image 
  with pyramids (1m_hillshade.zip). These geospatial data 
  files require geographic information system (GIS) software 
  for viewing.


  Disclaimer:

  Although these data have been processed successfully on a 
  computer system at the U.S. Geological Survey (USGS), no 
  warranty expressed or implied is made regarding the display 
  or utility of the data on any other system, or for general 
  or scientific purposes, nor shall the act of distribution 
  constitute any such warranty. The USGS shall not be held 
  liable for improper or incorrect use of the data described 
  and (or) contained herein.


  Contact Information:

  If you have any questions regarding this dataset please 
  feel free to contact:
  Adam R. Mosbrucker
  U.S. Geological Survey
  1300 SE Cardinal Court, Building 10, Suite 100
  Vancouver, WA 98683
  amosbrucker@usgs.gov
  (360) 993-8975


  Suggested citation:

  Mosbrucker, A.R., 2015, High-resolution digital elevation 
  model of lower Cowlitz and Toutle Rivers, adjacent to Mount 
  St. Helens, Washington, based on an airborne lidar survey 
  of October 2007: U.S. Geological Survey Data Series 936, 
  http://dx.doi.org/10.3133/ds936.

  ISSN 2327-638X (online)


  ----------------------------------------------------
  This Data Series includes the following Information. 
  ----------------------------------------------------

  Delivery Report

  MSH2007_delivery_report.pdf -- PDF file of report by 
  Watershed Sciences, Inc., under contract to USACE, on high-
  precision airborne lidar data collected October 22-27, 
  2007, that cover 273 square kilometers (106 square miles) 
  including lower Cowlitz River, Toutle River, North Fork 
  Toutle River (below edifice of Mount St. Helens), and lower 
  South Fork Toutle River.

  Digital Data

  1m_DEM.zip -- Digital-elevation data using bare-earth lidar 
  data as 1-m resolution Esri grid files.

  10m_DEM.zip -- Digital-elevation data using bare-earth 
  lidar data as 10-m resolution Esri grid files.

  1m_hillshade.zip -- 1-m resolution hillshade image with 
  pyramids.

  Metadata

  FGDC_Metadata.txt -- FGDC compliant metadata file for the 
  1- and 10-m digital elevation models and 1-m hillshade 
  image.