C. D. Rennie
R. B. Jacobson
R. D. Townsend
E. C. Jamieson
2011
<div class="NLM_sec NLM_sec_level_1 hlFld-Abstract"><p>Detailed mapping of bathymetry and apparent bed load velocity using a boat-mounted acoustic Doppler current profiler (ADCP) was carried out along a 388-m section of the lower Missouri River near Columbia, Missouri. Sampling transects (moving boat) were completed at 5- and 20-m spacing along the study section. Stationary (fixed-boat) measurements were made by maintaining constant boat position over a target point where the position of the boat did not deviate more than 3 m in any direction. For each transect and stationary measurement, apparent bed load velocity (<span class="equationTd"><span id="MathJax-Element-1-Frame" class="MathJax" data-mathml="<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"><msub><mi>v</mi><mi>b</mi></msub></math>"><span id="MathJax-Span-1" class="math"><span><span id="MathJax-Span-2" class="mrow"><span id="MathJax-Span-3" class="msub"><span id="MathJax-Span-4" class="mi">v</span><span id="MathJax-Span-5" class="mi">b</span></span></span></span></span><span class="MJX_Assistive_MathML">vb</span></span></span>) was estimated using ADCP bottom tracking data and high precision real-time kinematic (RTK) global positioning system (GPS). The principal objectives of this research are to (1) determine whether boat motion introduces a bias in apparent bed load velocity measurements; and (2) evaluate the reliability of ADCP bed velocity measurements for a range of sediment transport environments. Results indicate that both high transport (<span class="equationTd"><span id="MathJax-Element-2-Frame" class="MathJax" data-mathml="<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"><msub><mover accent="true"><mi>v</mi><mo>&#xAF;</mo></mover><mi>b</mi></msub><mo>&gt;</mo><mn>0.6</mn><mtext>&#x2009;</mtext><mtext>&#x2009;</mtext><mi mathvariant="normal">m</mi><mo>/</mo><mi mathvariant="normal">s</mi></math>"><span id="MathJax-Span-6" class="math"><span><span id="MathJax-Span-7" class="mrow"><span id="MathJax-Span-8" class="msub"><span id="MathJax-Span-9" class="mover"><span id="MathJax-Span-10" class="mi">v</span><span id="MathJax-Span-11" class="mo">¯</span></span><span id="MathJax-Span-12" class="mi">b</span></span><span id="MathJax-Span-13" class="mo">></span><span id="MathJax-Span-14" class="mn">0.6</span><span id="MathJax-Span-15" class="mtext"> </span><span id="MathJax-Span-16" class="mtext"> </span><span id="MathJax-Span-17" class="mi">m</span><span id="MathJax-Span-18" class="mo">/</span><span id="MathJax-Span-19" class="mi">s</span></span></span></span><span class="MJX_Assistive_MathML">v¯b>0.6 m/s</span></span></span>) and moving-boat conditions (for both high and low transport environments) increase the relative variability in estimates of mean bed velocity. Despite this, the spatially dense single-transect measurements were capable of producing detailed bed velocity maps that correspond closely with the expected pattern of sediment transport over large dunes.</p></div>
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10.1061/(ASCE)HY.1943-7900.0000373
en
American Society of Civil Engineers
Evaluation of ADCP apparent bed load velocity in a large sand-bed river: Moving versus stationary boat conditions
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