Quantifying Debris Flood Deposits in an Alaskan Fjord Using Multitemporal Digital Elevation Models

Area of Science:

• Geomorphology
• Hydrology
• Remote Sensing

Background:

• Sedimentation processes in drainage basins are crucial for understanding landscape evolution.
• Quantifying sediment budget changes due to extreme weather events requires accurate elevation data.
• Alaska's Japanese Creek drainage is susceptible to flood-related sediment transport.

Purpose of the Study:

• To estimate flood-related sedimentation in the Japanese Creek drainage over a 10-year period.
• To assess the effectiveness of the DEMs of Difference (DoD) technique for quantifying sediment redistribution.
• To correlate sediment budget changes with major flood events and precipitation data.

Main Methods:

• Utilized six Digital Elevation Models (DEMs) from existing LiDAR, GNSS, and newly generated dGNSS/SfM data.
• Applied the DEMs of Difference (DoD) technique to quantify volumetric changes and spatial patterns of sediment.
• Correlated sediment budget alterations with historical rainfall data and identified major flood events.

Main Results:

• Major flood events in 2006 and 2012 led to increased sedimentation across the drainage.
• The 2006 and 2012 floods added at least 70,100 and 53,900 cubic meters of sediment to the lower reaches, respectively.
• The DoD method proved effective in quantifying sediment redistribution volumes and patterns.

Conclusions:

• The study confirms that significant flood events are primary drivers of sedimentation in the Japanese Creek drainage.
• The integration of multiple DEM technologies enhances the accuracy of sediment budget analysis.
• The DoD technique is a valuable tool for monitoring geomorphic changes in response to hydrological events.