Monitoring Braided River Change Using Terrestrial Laser Scanning and Optical Bathymetric Mapping

Williams, R. D.; Brasington, James; Vericat, Damià; Hicks, Murray; Labrosse, Fred; Neal, Mark

doi:10.1016/b978-0-444-53446-0.00020-3

Cited by 51 publications

(79 citation statements)

References 29 publications

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“…The head of the Rees River is at a prominent col known as the Rees Saddle. The col is 80 m above Snowy Creek to the north, a former tributary of the Rees River that was captured by the Dart River (Williams et al, 2011). The southernmost boundary of the mapped area is at the junction of the Rees-Dart delta with Lake Wakatipu, taking in Glenorchy.…”

Section: Site Location and Descriptionmentioning

confidence: 99%

“…The valley is occupied by the Rees River, which is 41 km in length and drains a catchment area of 405 km 2 (Williams et al, 2011). The Richardson Mountains are located to the east of the river and the Forbes Mountains to the west, and both mountain ranges attain altitudes exceeding 2000 m.a.s.l.…”

Section: Site Location and Descriptionmentioning

confidence: 99%

“…DeScally et al (2010) examined some examples of debris flow fans and alluvial fans in the Rees Valley and surrounding area as part of a wider study of the morphometric properties of these two landforms. Modern fluvial sediment transfer processes have been examined by Brasington (2010) and Williams et al (2011Williams et al ( , 2013 who made detailed studies of the evolution of the braided lower reaches of the Rees River using Terrestrial Laser Scanning. Wild et al (2008) have also reconstructed recent sedimentation rates to the Rees and Dart delta.…”

Section: Site Location and Descriptionmentioning

confidence: 99%

“…Williams et al, 2011Williams et al, , 2013. Surveys reveal that the river bed has been aggrading around the road bridge that crosses the Rees River close to the southeast flank of Mt Alfred (1235800, 5030400), and in the braided reach down-river of the bridge (Otago Regional Council, 2008;Williams et al, 2011).…”

Section: Fluvialmentioning

confidence: 99%

“…In this respect, the geomorphological map of the Rees catchment provides an important context for other on-going investigations in the area concerned with modern-braided river dynamics (e.g. Brasington, 2010;Williams et al, 2013;Williams et al, 2011), former glacial conditions and processes, and changes in the level of Lake Wakatipu since the LGM (e.g. Wild et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

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Geomorphology of the Rees Valley, Otago, New Zealand

Cook¹,

Quincey

Brasington

2013

Journal of Maps

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We present a 1:33,333 geomorphological map of the Rees Valley, Otago, New Zealand. The Rees River drains an area of 405 km 2 and feeds into the head of Lake Wakatipu. This area has been affected by a range of geomorphological processes including tectonic activity, glacial erosion and deposition, mass movement, fluvial action, and base (lake) level change. Mapping was achieved by a combination of interpretation from SPOT 5 HRG satellite imagery and ground-truthing. The map presents the current distribution of landforms and sediments associated with the wide variety of contemporary and past geomorphological processes. It represents the most detailed and finest resolution geomorphological map of this region to date, and hence a number of features have been mapped and described for the first time. The map will assist on-going studies in the Rees catchment that seek to understand fluvial sediment transport and associated flood hazards, the dynamics of former glaciers, base level change associated with a drop in the level of Lake Wakatipu, and mass movement hazards.

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Section: Site Location and Descriptionmentioning

confidence: 99%

Section: Site Location and Descriptionmentioning

confidence: 99%

Section: Site Location and Descriptionmentioning

confidence: 99%

Section: Fluvialmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Geomorphology of the Rees Valley, Otago, New Zealand

Cook¹,

Quincey

Brasington

2013

Journal of Maps

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Linking the spatial distribution of bed load transport to morphological change during high‐flow events in a shallow braided river

et al. 2015

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This paper provides novel observations linking the connections between spatially distributed bed load transport pathways, hydraulic patterns, and morphological change in a shallow, gravel bed braided river. These observations shed light on the mechanics of braiding processes and illustrate the potential to quantify coupled material fluxes using remotely sensed methods. The paper focuses upon a 300 m long segment of the Rees River, New Zealand, and utilizes spatially dense observations from a mobile acoustic Doppler current profiler (aDcp) to map depth, velocity, and channel topography through a sequence of high-flow events. Apparent bed load velocity is estimated from the bias in aDcp bottom tracking and mapped to indicate bed load transport pathways. Terrestrial laser scanning (TLS) of exposed bar surfaces is fused with the aDcp surveys to generate spatially continuous digital elevation models, which quantify morphological change through the sequence of events. Results map spatially distributed bed load pathways that were likely to link zones of erosion and deposition. The coherence between the channel thalweg, zone of maximum hydraulic forcing, and maximum apparent bed load pathways varied. This suggests that, in places, local sediment supply sources exerted a strong control on the distribution of bed load, distinct from hydraulic forcing. The principal braiding mechanisms observed were channel choking, leading to subsequent bifurcation. Results show the connection between sediment sources, pathways, and sinks and their influence on channel morphology and flow path directions. The methodology of coupling spatially dense aDcp surveys with TLS has considerable potential to understand connections between processes and morphological change in dynamic fluvial settings.

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Error modeling of DEMs from topographic surveys of rivers using fuzzy inference systems

Bangen

Hensleigh

McHugh

et al. 2016

Water Resources Research

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Digital elevation models (DEMs) have become common place in the earth sciences as a tool to characterize surface topography and set modeling boundary conditions. All DEMs have a degree of inherent error that is propagated to subsequent models and analyses. While previous research has shown that DEM error is spatially variable it is often represented as spatially uniform for analytical simplicity. Fuzzy inference systems (FIS) offer a tractable approach for modeling spatially variable DEM error, including flexibility in the number of inputs and calibration of outputs based on survey technique and modeling environment. We compare three FIS error models for DEMs derived from TS surveys of wadeable streams and test them at 34 sites in the Columbia River basin. The models differ in complexity regarding the number/type of inputs and degree of site-specific parameterization. A 2-input FIS uses inputs derived from the topographic point cloud (slope, point density). A 4-input FIS adds interpolation error and 3-D point quality. The 5-input FIS adds bed-surface roughness estimates. Both the 4 and 5-input FIS model output were parameterized to site-specific values. In the wetted channel we found (i) the 5-input FIS resulted in lower mean dz due to including roughness, and (ii) the 4 and 5-input FIS resulted in a higher standard deviation and maximum dz due to the inclusion of sitespecific bank heights. All three FIS gave plausible estimates of DEM error, with the two more complicated models offering an improvement in the ability to detect spatially localized areas of DEM uncertainty. Key Points:Compare fuzzy inference system DEM error models for total station surveys of streams Including roughness decreases in-channel mean error estimate Including site-specific bank heights increases in-channel standard deviation and max error estimate

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Monitoring Braided River Change Using Terrestrial Laser Scanning and Optical Bathymetric Mapping

Cited by 51 publications

References 29 publications

Geomorphology of the Rees Valley, Otago, New Zealand

Geomorphology of the Rees Valley, Otago, New Zealand

Linking the spatial distribution of bed load transport to morphological change during high‐flow events in a shallow braided river

Error modeling of DEMs from topographic surveys of rivers using fuzzy inference systems

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