The Valley Bottom Extraction Tool (V-BET): A GIS tool for delineating valley bottoms across entire drainage networks

Gilbert, Jordan T.; Macfarlane, William W.; Wheaton, Joseph M.

doi:10.1016/j.cageo.2016.07.014

Cited by 58 publications

(66 citation statements)

References 32 publications

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“…Many terrain indices [19][20][21][22] have been developed in order to build up a stronger connection between water presence and topography. Most of these terrain indices can generally be categorized into two groups, valley bottom based and drainage based.…”

Section: Introductionmentioning

confidence: 99%

A Comparison of Terrain Indices toward Their Ability in Assisting Surface Water Mapping from Sentinel-1 Data

Huang

Nguyen

Zhang

et al. 2017

IJGI

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Abstract:The Sentinel-1 mission provides frequent coverage of global land areas and is hence able to monitor surface water dynamics at a fine spatial resolution better than any other Synthetic Aperture Radar (SAR) mission before. However, SAR data acquired by Sentinel-1 also suffer from terrain effects when being used for mapping surface water, just as other SAR data do. Terrain indices derived from Digital Elevation Models (DEMs) are easy but effective approaches to reduce this kind of interference, considering the close relationship between surface water movement and topography. This study compares two popular terrain indices, namely the Multi-resolution Valley Bottom Flatness (MrVBF) and the Height Above Nearest Drainage (HAND), toward their performance on assisting surface water mapping using Sentinel-1 SAR data. Four study sites with different terrain characteristics were selected to cover a very wide range of topographic conditions. For two of these sites that are floodplain dominated, both normal and flooded scenarios were examined. MrVBF and HAND values for the whole study areas, as well as statistics of these values within water areas were compared. The sensitivity of applying different thresholds for MrVBF and HAND to mask out terrain effect was investigated by adopting quantity disagreement and allocation disagreement as the accuracy indicators. It was found that both indices help improve water mapping, reducing the total disagreement by as much as 1.6%. The HAND index performs slightly better in most of the study cases, with less sensitivity to thresholding. MrVBF classifies low-lying areas with more details, which sometimes makes it more effective in eliminating false water bodies in rugged terrain. It is therefore recommended to use HAND for large scale or global scale water mapping. However, for water detection in complex terrain areas, MrVBF also performs very well.

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Section: Introductionmentioning

confidence: 99%

A Comparison of Terrain Indices toward Their Ability in Assisting Surface Water Mapping from Sentinel-1 Data

Huang

Nguyen

Zhang

et al. 2017

IJGI

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“…valley bottom including 1.5-dimensional (1.5D), twodimensional (2D) or three-dimensional (3D) hydraulic modeling, manual delineation, the Fluvial Corridor Tool (Roux et al, 2015) or the VBET (Valley Bottom Extraction Tool) (Gilbert et al, 2016). Depending on the resolution and scale of the valley bottom polygon being used, it may be necessary to provide a small buffer (similar to resolution of mapping) on the channel extent to ensure an intersection.…”

Section: Network Preparation and Processing Extentmentioning

confidence: 99%

“…However, such measures produce only confined and unconfined binaries that occur on either side of a discrete valley width/bankfull width threshold (Wohl et al, 2012;Wohl, 2013). Similarly, Roux et al (2015) and Gilbert et al (2016) developed a suite of geographic information system (GIS)-based tools designed to extract valley bottoms for use in measuring valley confinement. Rosgen, 1996), use the ratio of bankfull channel width to width at 2× bankfull height.…”

Section: Introductionmentioning

confidence: 99%

Mapping valley bottom confinement at the network scale

O'Brien

Wheaton

Fryirs

et al. 2019

Earth Surf Processes Landf

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In this article, we demonstrate the application of a continuous confinement metric across entire river networks. Confinement is a useful metric for characterizing and discriminating valley setting. At the reach scale, valley bottom confinement is measured and quantified as the ratio of the length of channel confined on either bank by a confining margin divided by the reach length. The valley bottom is occupied by the contemporary floodplain and/or its channel(s); confining margins can be any landform or feature that makes up the valley bottom margin, such as bedrock hillslopes, terraces, fans, or anthropogenic features such as stopbanks or constructed levees. To test the reliability of calculating confinement across entire networks, we applied our geoprocessing scripts across four physiographically distinct watersheds of the Pacific Northwest, USA using freely available national datasets. Comparison of manually digitized and mapped with modeled calculations of confinement revealed that roughly one‐third of reaches were equivalent and about two‐thirds of the sites differ by less than ±15%. A sensitivity analysis found that a 500 m reach segmentation length produced reasonable agreement with manual, categorical, expert‐derived analysis of confinement. Confinement accuracy can be improved (c. 4% to 17% gains) using a more accurately mapped valley bottom and channel position (i.e. with higher‐resolution model inputs). This is particularly important when differentiating rivers in the partly confined valley setting. However, at the watershed scale, patterns derived from mapping confinement are not fundamentally different, making this a reasonably accurate and rapid technique for analysis and measurement of confinement across broad spatial extents. © 2019 John Wiley & Sons, Ltd.

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“…, 2013 and other geographic information system (GIS) readable imagery, in conjunction with the National Elevation Dataset (NED; USGS, 1999) and National Hydrography Dataset (NHD; USGS, 2007), to document the landscape-scale physiographic attributes such as underlying geology, vegetation patterns and composition, relief, drainage density and a thorough visual interpretation of stream and valley attributes. Air photo analysis is critical for validating preliminary mapping of the valley bottom (Gilbert et al, 2016), channel, and where aerial photo resolution allows, for bed material inference and in-channel geomorphic units. Determining reach breaks (e.g.…”

Section: Desktop Analyses and Stream Surveymentioning

confidence: 99%

“…The geomorphology of river channels and their floodplains is key to understanding the processes that create and maintain habitat conditions suitable for salmonid species (Beechie & Sibley, 1997;Gilbert, Macfarlane, & Wheaton, 2016;Wheaton et al, 2010). An analysis of a river's current geomorphic condition and its recovery potential not only informs potential restoration targets and priorities, it can also support assessments of salmonid-habitat relationships at a variety of spatial scales (e.g.…”

Section: Introductionmentioning

confidence: 99%

A geomorphic assessment to inform strategic stream restoration planning in the Middle Fork John Day Watershed, Oregon, USA

et al. 2017

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A geomorphic assessment of the Middle Fork John Day Watershed, Oregon, USA, was used to generate a hierarchical, map-based understanding of watershed impairments and potential opportunities for improvements. Specifically, we (1) assessed river diversity (character and behavior) and patterns of reach types (and their controls); (2) evaluated the geomorphic condition of the streams; (3) interpreted their geomorphic recovery potential; and (4) synthesized the above into a hypothetical, strategic management plan. Collectively, these maps can set bounds and provide realistic guidance for river rehabilitation, design and implementation efforts. Fifteen distinct reach types were identified, two-thirds of which are found along perennial streams. On the basis of a variety of geo-indicators, approximately two-thirds of all perennial stream reaches were found to be in 'good' geomorphic condition, whereas one-third had departed to 'moderate' and 'poor' condition. Departures from 'good' condition were primarily related to riparian vegetation removal, conversion of floodplain to agricultural land uses (farming and grazing), logging, and channel bed dredge mining for gold. Encouragingly, the majority of reaches classified as being in moderate geomorphic condition were found to have high recovery potential. While our geomorphic assessment has practical utility for informing physically realistic expectation management for efforts like salmonid habitat restoration, the maps themselves are the key vehicle for communicating and visualizing among stakeholders. ARTICLE HISTORY

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The Valley Bottom Extraction Tool (V-BET): A GIS tool for delineating valley bottoms across entire drainage networks

Cited by 58 publications

References 32 publications

A Comparison of Terrain Indices toward Their Ability in Assisting Surface Water Mapping from Sentinel-1 Data

A Comparison of Terrain Indices toward Their Ability in Assisting Surface Water Mapping from Sentinel-1 Data

Mapping valley bottom confinement at the network scale

A geomorphic assessment to inform strategic stream restoration planning in the Middle Fork John Day Watershed, Oregon, USA

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