2016 Old River Control Complex sedimentation data : supplement to Old River Control Complex sedimentation investigation (MRG&amp;P Report No. 6)

Jones, Kathleen F.; Abraham, David D.; McAlpin, Tate O.; Ganesh, Naveen

doi:10.21079/11681/27109

Cited by 1 publication

(4 citation statements)

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“…To discern possible estimation errors from the two different approaches, we compared the estimated BML using Yang's formula with measured BML by the USACE. The BML measurements were conducted in 2010, 2011, and 2016 by 10 field trips (Heath et al, 2015; Jones et al, 2018). During each trip, water and sediment fluxes were determined using an Acoustic Doppler Current Profiler (ADCP) and multibeam sounds.…”

Section: Discussionmentioning

confidence: 99%

“…Discharge ranges correspond with low, action, intermediate, high, and peak flows as defined by National Oceanic and Atmospheric Administration (NOAA) for stages at Red River Landing could affect downstream channel dynamics, sedimentation and, therefore, the long-term stability of the bifurcated channels. This knowledge can be useful for the management and operation of the (Heath et al, 2015;Jones et al, 2018). F I G U R E 1 2 Comparison between estimated bed material load (BML) using Yang's (1973)…”

Section: Discussionmentioning

confidence: 99%

“…However, Yang's, 1979 formula is more appropriate when the sand concentration is higher than 100 ppm which is not the case in the Lower Mississippi River (Joshi & Xu, 2015). The USACE recently conducted field measurements on bedload and bed material load at several sites near the ORCS (Heath et al, 2015; Jones, Abraham, McAlpin, & Ganesh, 2018). This supplies us with an excellent opportunity to study bed material load using the classic sediment transport formulas.…”

Section: Methodsmentioning

confidence: 99%

“… Q s = daily bed material discharge (metric tons/day).where G w is the water discharge by weight (kg/s) and the coefficient in ) (86.4) transform bed material discharge from kg per second to metric tons per day. In Equation ), a median grain size (D 50 ) of 0.34 mm was used for the Mississippi River and a D 50 of 0.37 mm was used for the Outflow Channel based on field measurements of bed sediment grain size in 2016 (Jones et al, 2018). We calculated the daily bed material load at Site 1 (upstream), Site 2 (downstream), and Site 3 (the end of the Outflow Channel) for the 10‐year study period and assessed their transport rates under varying flow conditions.…”

Section: Methodsmentioning

confidence: 99%

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Estimating bed material fluxes upstream and downstream of a controlled large bifurcation ‐ the Mississippi‐Atchafalaya River diversion

Wang

2020

Hydrological Processes

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Bed material transport at river bifurcations is crucial for channel stability and downstream geomorphic dynamics. However, measurements of bed material transport at bifurcations of large alluvial rivers are difficult to make, and standard estimates based on the assumption of proportional partitioning of flow and bedload transport at bifurcations may be erroneous. In this study, we employed a combined approach based on observed topographic change (erosion/deposition) and bed material transport predicted from a one‐dimensional model to investigate bed material fluxes near the engineering‐controlled Mississippi‐Atchafalaya River diversion, which is of great importance to sediment distribution and delivery to Louisiana's coast. Yang's (1973) sediment transport equation was utilized to estimate daily bed material loads upstream, downstream, and through the diversion during 2004–2013. Bathymetric changes in these channels were assessed with single beam data collected in 2004 and 2013. Results show that over the study period, 24% of the Mississippi River flow was diverted into the Atchafalaya River, while the rest remained in the mainstem Mississippi. Upstream of the diversion, the bed material yield was predicted to be 201 million metric tons (MT), of which approximately 35 MT (i.e., 17%) passed through the bifurcation channel to the Atchafalaya River. The findings from this study reveal that in the mainstem Mississippi, the percentage of bed material diversion (83%) is larger than the percentage of flow diversion (76%); Conversely, the diversion channel receives a disproportionate amount of flow (24%) relative to bed material supply (17%). Consequently, severe bed scouring occurred in the controlled Outflow Channel to the Atchafalaya River, while riverbed aggradation progressed in the mainstem Mississippi downstream of the diversion structures, implying reduced flow capacity and potential risk of a high backwater during megafloods. The study demonstrates that Yang's sediment transport equation provides plausible results of bed material fluxes for a highly complicated large river diversion, and that integration of the sediment transport equation with observed morphological changes in riverbed is a valuable approach to investigate sediment dynamics at controlled river bifurcations.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%