GEOGRAPHIC INFORMATION

Channel Migration Zone of the Clark Fork, Bitterroot River to Huson, 2009

Data Provider DTM Consulting, Inc.
Applied Geomorphology, Inc.
Date 2009
Content Type Downloadable Data
Abstract A Channel Migration Zone map and associated report was completed for approximately 20 miles of the Clark Fork River from the Bitterroot River confluence, downstream to the Six Mile Creek confluence near Huson.Channel Migration Zone mapping is based on the understanding that rivers are dynamic and move laterally across their floodplains through time. Over any given time period, rivers occupy a corridor area whose width is dependent on rates of bank erosion. The map units contained in the data include the following: 1 - Active Channel: The active channel reflects the channel course in 2005. 2 - Historic Migration Zone (HMZ): This unit reflects the area where active channels of the Clark Fork River have existed between 1955 and 2005. 3 - Erosion Buffer: The erosion buffer reflects a calculated erosion buffer based on over one hundred measurements of channel migration. The main buffer is twice the mean 50-year migration rate. The larger buffer extending slightly beyond reflects twice the 75th percentile value measured for the 1955-2005 time frame. 4 - Bedrock: Geologic units that are older than the valley bottom sediments are mapped as bedrock. These areas were not assigned erosion buffers or geotechnical setbacks, as any risk of erosion in these areas is highly site-specific and beyond the realm of this study. 5 - Avulsion Hazard Zone (AHZ): Areas where topographic conditions suggest potential channel relocation or reactivation are mapped as the AHZ. These areas reflect sites where during flood events, these channels are prone to reactivation or flooding.
Purpose
Supplemental Information
Please consult technical memo titled 'Clark Fork River CMZ Pilot,' created December 15, 2009, for Peter Nielsen at the Missoula County planning office prior to using these data for analysis. The Montana State Library provides this product/service for informational purposes only. The Library did not produce it for, nor is it suitable for legal, engineering, or surveying purposes. Consumers of this information should review or consult the primary data and information sources to ascertain the viability of the information for their purposes. The Library provides these data in good faith but does not represent or warrant its accuracy, adequacy, or completeness. In no event shall the Library be liable for any incorrect results or analysis; any direct, indirect, special, or consequential damages to any party; or any lost profits arising out of or in connection with the use or the inability to use the data or the services provided. The Library makes these data and services available as a convenience to the public, and for no other purpose. The Library reserves the right to change or revise published data and/or services at any time.
Data Access http://geoinfo.msl.mt.gov/Home/data/montana_channel_migration_zones/projects/clark_fork_-_bitterroot_to_huson.aspx
Distributor Montana State Library
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Email: geoinfo@mt.gov
Distribution liability The Montana State Library provides this product/service for informational purposes only. The Library did not produce it for, nor is it suitable for legal, engineering, or surveying purposes. Consumers of this information should review or consult the primary data and information sources to ascertain the viability of the information for their purposes. The Library provides these data in good faith but does not represent or warrant its accuracy, adequacy, or completeness. In no event shall the Library be liable for any incorrect results or analysis; any direct, indirect, special, or consequential damages to any party; or any lost profits arising out of or in connection with the use or the inability to use the data or the services provided. The Library makes these data and services available as a convenience to the public, and for no other purpose. The Library reserves the right to change or revise published data and/or services at any time.
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Metadata date 12/01/2014