T316 Change Detection Photogrammetry in Earth Science

Wednesday, 25 October 2017
8:00 AM - 12:00 PM
Chelan 4

RAPID CHARACTERIZATION OF STREAMBED MICROTOPOGRAPHY IN MOUNTAIN CHANNELS: METHODS AND APPLICATION USING STRUCTURE-FROM-MOTION PHOTOGRAMMETRY

Paper number: T316-9
Program: Technical Sessions
Time: 10:10 AM – 10:30 AM

Authors

Abstract

Erosion and sediment transport in mountain rivers depend to first order on the size distribution of channel-bed sediment and flow resistance, both of which are encoded in streambed microtopography. Recent advances in structure-from-motion (SfM) multi-view photogrammetry have radically lowered the cost and effort of acquiring high-resolution topographic surveys, which are particularly well-suited for characterizing streambed microtopography at dry or low-flow conditions. Minimal equipment and power requirements make field surveys of typically inaccessible channels feasible, allowing for rapid collection of baseline datasets for quantifying bed-state and assessing landscape change. Here we outline a workflow focused on efficient field data collection of streambed microtopography using ground-based SfM methods. We present field techniques for scaling and referencing datasets with minimal equipment, and evaluate optimal scales of analysis for point-cloud-based processing and mesh generation using statistical properties of streambed microtopography. We apply this methodology to field examples in Pennsylvania, California, and Taiwan to: 1) evaluate connections between streambed microtopography and grain size distribution and particle shape; 2) quantify boulder mobility and erosion using repeat surveys; and 3) integrate field-surveyed streambed microtopography into computational fluid dynamics models to predict flow resistance.

Geological Society of America Abstracts with Programs. Vol. 49, No. 6

doi: 10.1130/abs/2017AM-306648

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