Abstract: Session C  11:20 am (Back to Session C)
Fusion of Topographic Data for River Valley Geomorphic Studies: Examples from Grand Canyon’s Colorado River, Arizona

Stephanie V. Coffman
Stantec Consulting Services Inc.
Fort Worth, TX

Authors:  Joshua Caster, US Geological Survey, Grand Canyon Monitoring and Research Center, Flagstaff, AZ
Joel B. Sankey, US Geological Survey, Grand Canyon Monitoring and Research Center, Flagstaff, AZ
Alan Kasprak, US Geological Survey, Grand Canyon Monitoring and Research Center, Flagstaff, AZ
Joel Unema, US Geological Survey, Arizona Water Science Center, Flagstaff, AZ
Stephanie Coffman, Stantec Consulting Services, Arlington, TX

Two Objectives:
1.  Assess fusion of topographic data collected through different survey methods for landscape
2. Use survey data from different methods and time periods to investigate geomorphic change within
     the Colorado River and Grand Canyon, AZ

Quantifying the effects of flow alteration on river channel and valley geomorphology is often difficult given the highly connected nature of fluvial and non-fluvial geomorphic processes. For geomorphologists, a high-resolution topographic survey provides a resource for characterizing landforms for local or valley-scale geomorphic settings. Advancements in the field of light detection and ranging (LIDAR) and modern photogrammetry techniques, such as structure from motion (SFM) photogrammetry, have increased the availability of these data, providing greater opportunity for quantifying landscape changes through repeat survey. These technological advancements, however, have presented both the dilemma and opportunity to compare and fuse topographic data collected by differing methods and resolutions. In this study, we first evaluate contemporary data collected within Grand Canyon, AZ using LIDAR, photogrammetry and total station surveys to assess data agreement between methods. Next, we analyze repeat survey data collected with these methods to assess landscape change at sites undergoing a combination of fluvial, aeolian and hillslope geomorphic processes. We find that all three survey methods show comparable data in terms of error budgets on a point basis, though the extent of comparison is limited by physical context, post processing procedure and survey resolution. We demonstrate a novel approach for quantifying the relative contributions of sediment transport processes using repeat survey data and show how incorporating multiple data collection methods can be used to supplement geomorphic change analysis where data from a single method is either imperfect, unavailable or impractical. We anticipate that this study will be useful for landscape characterization and assessments of geomorphic change on local or valley-scale contexts, specifically where previous and future mapping efforts incorporate multiple survey data collection techniques.