James Thomas Dietrich

University of Texas at Austin | UT · Center for Space Research

Recent developments in the remote sensing of fluvial systems have provided researchers with unprecedented views on the complexity of rivers. An aerial perspective is key to mapping and understanding the river at a variety of spatial scales. I employed a helicopter-mounted digital SLR camera and Structure-from-Motion (SfM) photogrammetry to bridge t...

http://onlinelibrary.wiley.com/doi/10.1002/esp.4012/full The declining costs of small Unmanned Aerial systems (sUAS), in combination with Structure from Motion (SfM) photogrammetry have triggered renewed interest in image-based topography reconstruction. However, the potential uptake of sUAS-based topography is limited by the need for ground contr...

http://onlinelibrary.wiley.com/doi/10.1002/esp.4060/abstract Stream bathymetry is a critical variable in a number of river science applications. In larger rivers, bathymetry can be measured with instruments such as sonar (single or multi-beam), bathymetric airborne LiDAR, or acoustic doppler current profilers. However, in smaller streams with dept...

Much of the geomorphic work of rivers occurs underwater. As a result, high resolution quantification of geomorphic change in these submerged areas is important. Currently, to quantify this change, multiple methods are required to get high resolution data for both the exposed and submerged areas. Remote sensing methods are often limited to the expos...

A major advance in global bathymetric observation occurred in 2018 with the launch of NASA’s ICESat-2 satellite, carrying a green-wavelength, photon-counting lidar, the Advanced Topographic Laser Altimeter System (ATLAS). Although bathymetric measurement was not initially a design goal for the mission, pre- and post-launch studies revealed ATLAS’s...

Dams fragment the longitudinal flux of sediment and obstruct fish passage. To help remediate these impacts, dam removal has become an important tool in the river restoration toolkit. Scientifically, these removals also provide an important experimental design, fixed in time and space, to quantify geomorphic and ecological responses to removal of a...

Ephemeral rivers in arid regions act as linear oases, where corridors of vegetation supported by accessible groundwater and intermittent surface flows provide biological refugia in water-limited landscapes. The ecological and hydrological dynamics of these systems are poorly understood compared to perennial systems and subject to wide variation ove...

Rivers are among the world's most threatened ecosystems. Enabled by the rapid development of drone technology , hyperspatial resolution (< 10 cm) images of fluvial environments are now a common data source used to better understand these sensitive habitats. However, the task of image classification remains challenging for this type of imagery and t...

Ephemeral rivers are key features of desert ecosystems, providing shallow groundwater and occasional surface flow, but compared to perennial systems, the structure of riparian forests in ephemeral rivers and their interactions with the hydrologic regime are poorly understood. This study examines the distribution of riparian woody species in the eph...

River environments are among the world’s most threatened ecosystems. Enabled by the rapid development of drone technology, hyperspatial resolution (<10 cm) images of fluvial scenes are now a common data source used to better understand these sensitive habitats. However, the task of image classification remains challenging for this type of imagery a...

Most river system analyses use either intensive, small-area surveys, or extensive, low-resolution surveys. Recent research postulates that both high-resolution and river-extent information are necessary to understand fundamental questions of river processes, such as patterns of critical habitat, sediment links, and river instability. As part of a l...

The extreme rainfall of October 2015 in South Carolina generated numerous dam failures and spawned the flood of record at most U.S. Geological Survey stream gauges. Detailed field sampling and systematic image analysis are used to document the immediate and sustained geomorphic adjustments at four failed dams within the urbanized Gills Creek waters...

Quantifying the rates of geomorphic change is critical for a range of applications within river science and management, including monitoring the evolution of river restoration and assessing the impacts of flow modifications and engineering structures on habitat availability. • The tools available for monitoring small river systems at high spatial r...

Aeolian processes are important drivers of geomorphic change in cold regions. Because these processes often occur at slow timescales over large areas, it can be difficult to quantify rates using traditional field methods. In the Kangerlussuaq region of Greenland, strong katabatic winds have shaped distinct erosional landforms, or deflation patches,...

http://onlinelibrary.wiley.com/doi/10.1002/rra.2989/abstract It has long been known that large wood in rivers increases channel complexity and is a primary driver of geomorphic change in forested mountain streams in the Pacific Northwest. Studies analyzing the presence and distribution of fluvial wood are often limited in their spatial extents to...

AVAILABLE FROM: https://scholarsbank.uoregon.edu/xmlui/handle/1794/18701---------------------------------------------- Since 2011, Structure-from-Motion Multi-View Stereo Photogrammetry (SfM or SfM-MVS) has gone from an overlooked computer vision technique to an emerging methodology for collecting low-cost, high spatial resolution three-dimensional...

The production of topographic datasets is of increasing interest and application throughout the geomorphic sciences, and river science is no exception. Consequently, a wide range of topographic measurement methods have evolved. Despite the range of available methods, the production of high resolution, high quality digital elevation models (DEMs) re...

The production of high-resolution topographic datasets is of increasing concern and application throughout the geomorphic sciences, and river science is no exception. Consequently, a wide range of topographic measurement methods have evolved. Despite the range of available methods, the production of high resolution, high quality digital elevation m...

We present a new approach to mapping both the above- and below-water three-dimensional riverscape environment using nothing but off-the-shelf (and geometrically unconstrained) cameras and a new approach called “Structure from Motion” (SfM). Multiple images taken from different vantage points can be converted to 3D topographic point clouds using aut...