Mississippi River Hydrodynamic and Delta Management Study (MRHDM) - Geomorphic Assessment

Little, Charles D.; Biedenharn, David S.

doi:10.21236/ada606456

Cited by 16 publications

(39 citation statements)

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“…There was no significant difference in the dredging volume during the two periods (Little & Biedenharn, ). The annual sediment and sand load at Tarbert Landing (RK 493) had no significant trend either (Joshi & Xu, ; Rosen & Xu, ).…”

Section: Discussionmentioning

confidence: 92%

“…However, in the LmMR, dredging is mainly operated in the 11 reaches in reach C between RK 381 and RK 241 (detailed dredging information shown in Table S2). Considering the amount of annually dredged sediment in this reach (i.e., ~13 × 10 6 m 3 ; Little & Biedenharn, ), the riverbed of reach C has actually gained 270 × 10 6 m 3 sediment during 1992–2004 and 30 × 10 6 m 3 during 2004–2013. The estimated changes in bed elevation and cumulative sediment volume in consideration of dredging activities are shown in Figures and when the average annual dredging amount in each reach was added back to reach C. Different from reach C, reverse trends were observed in reach D (i.e., +12 versus −70 × 10 6 m 3 ; Table ).…”

Section: Discussionmentioning

confidence: 99%

“…In this 500‐km river reach, dredging has been mainly conducted on the crossings between Baton Rouge (RK 368) and New Orleans (RK 165) to keep the channel navigable. The annual dredging volume during 1988–2011 has been reported to be approximately 13 × 10 6 m 3 (Little & Biedenharn, ).…”

Section: Methodsmentioning

confidence: 99%

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Decadal‐Scale Riverbed Deformation and Sand Budget of the Last 500 km of the Mississippi River: Insights Into Natural and River Engineering Effects on a Large Alluvial River

Wang

2018

JGR Earth Surface

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Alluvial rivers are shaped by interactions of flow and sediment transport. Their lower reaches to the world's oceans are highly dynamic, often presenting engineering and management challenges. Here we analyzed over 6,000 single-beam cross-sectional measurements surveyed in 1992, 2004, and 2013 in the last 500-km reach of the highly engineered Mississippi River, also known as the lowermost Mississippi River or LmMR, starting from the river's Gulf outlet to its avulsion into the Atchafalaya River. We applied inverse distance weighted interpolation to downscale the survey records into 10 × 10 m digital elevation models. We assessed riverbed deformation from bank to bank and quantified changes in riverbed sediment volume. The goal of our study is to test the hypothesis that the lower reach of a large alluvial river can function as a conduit for sediment transport under the current engineering focus of navigation safety and flood control. Our analysis shows that in the past two decades, nearly 70% of the riverine sand was trapped within the LmMR, and continuous riverbed aggradation occurred below the Mississippi-Atchafalaya diversion, presenting favorable backwater conditions for avulsion. Backwater effects have mainly controlled riverbed deformation in the LmMR, while flow reduction may have also contributed to the channel aggradation in the uppermost and lowermost reaches. The study reveals the considerable complexity of geomorphic responses of a large alluvial river to human interventions, strongly suggesting that future river engineering and management of the world's alluvial rivers should focus on strategies and solutions that will improve sediment transport.Over the past century, the natural fluvial processes of many alluvial rivers have been altered by human interventions, including levee construction and other engineering practices, that is, channel cutoffs, dredging,

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Section: Discussionmentioning

confidence: 92%

Section: Discussionmentioning

confidence: 99%

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Decadal‐Scale Riverbed Deformation and Sand Budget of the Last 500 km of the Mississippi River: Insights Into Natural and River Engineering Effects on a Large Alluvial River

Wang

2018

JGR Earth Surface

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“…The development of a ratings curve for a plot of suspended sediment load versus discharge ( Figure 5) has been conducted utilizing many different curve fitting methods, including the use of individual annual curves (Horowitz 2003) and semi-automated procedures (Koltun et al 1994;Runkel et al 2004). For the present study, to allow inter-comparison with the author's previous efforts in the Louisiana section of the Mississippi River (Allison et al 2012;Little and Biedenharn 2014), two methods of curve fitting the data were conducted. As reported in Tables 3 and 4, total and sand-suspended sediment load at all stations were calculated using a quadratic best fit regression following Little and Biedenharn (2014):…”

Section: Sediment Discharge Calculationsmentioning

confidence: 99%

“…For the present study, to allow inter-comparison with the author's previous efforts in the Louisiana section of the Mississippi River (Allison et al 2012;Little and Biedenharn 2014), two methods of curve fitting the data were conducted. As reported in Tables 3 and 4, total and sand-suspended sediment load at all stations were calculated using a quadratic best fit regression following Little and Biedenharn (2014):…”

Section: Sediment Discharge Calculationsmentioning

confidence: 99%

Suspended sediment loads and tributary inputs into the Mississippi River below St. Louis, MO, 1990–2013 : A comparison with the Keown et al. (1981) report

Biedenharn¹,

Little²

2017

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Annual suspended sediment loads and water discharges were calculated in the Mississippi River main-stem channel and major tributary inputs at gaging stations from St. Louis, MO, to Belle Chasse, LA, for the period of water years 1990 to 2013. The purpose was to (1) quantify changes in the Mississippi River sediment budget by linking with an earlier study for the periods of pre-1953pre- and 1970pre- -1978pre- (Keown et al. 1981 and (2) examine the role of anthropogenic (e.g., dams, river control works, soil conservation practices) and natural (e.g., rainfall and denudation rates) factors in controlling these changes. The present report focuses on (1) a first-order comparison of changes in station-specific sediment loads with the earlier Keown results, (2) documenting data quality and data comparison issues observed in the data, and (3) identifying possible additional gaging station sites at critical junctures that would improve future sediment budget assessments for the Mississippi River. It is anticipated that sediment budgets will provide a powerful framework when combined with other geomorphic assessment tools (e.g., specific gage records, channel geometry changes) to aid in unraveling the complex morphological processes that drive the Mississippi River. This integration is also planned for future, comprehensive MRG&P efforts.

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Estimate of decadal‐scale riverbed deformation and bed‐load sediment transport during flood events in the lowermost Mississippi River

Mossa

Jaeger

2022

Earth Surf Processes Landf

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Riverbed changes are important to applications in engineering in the environment, such as navigation, salt‐water intrusion and habitat quality. This study employed decadal hydrographic data over the past 50 years (1963–2013), as well as daily water stages and discharges to outline the long‐term channel morphological changes and bed‐load sediments deposited by floods in the lowermost Mississippi River (LMR). To generate accurate bathymetric digital elevation models (DEMs), we interpolated the hydrographic survey in a channel‐centred coordinate system by employing ordinary kriging with anisotropy. Riverbed deformations were estimated by subtracting the elevations between DEMs at two different times to generate a series of DoDs (DEM of difference). The results from DoDs exhibit temporal riverbed change patterns and also reveal net degradation after the completion of the Old River Control Structure in 1963, except for the period 1992–2004. Spatially, over 32% of the total area experienced continuous erosion, with only 0.4% having continuous aggradation. Historical erosion over the past 50 years could be removing the alluvial veneer in sections of the river, and exposing more non‐alluvial sediments, particularly between river kilometre RK 230 and RK 40. Our analysis also shows that riverbed deformation patterns are mainly controlled by flood events, backwater effects, as well as the drawdown effect near the Bonnet Carré spillway. In this study, we also examine whether the LMR traps bed‐load sediment under flood conditions. The probability distribution estimated by Monte Carlo simulation suggests only low amounts of bed‐load sediments are deposited on the channel bed during floods. Spatially, the short‐term bed‐load erosion/deposition pattern roughly matches the decadal‐scale riverbed deformation estimated from DoDs. Moreover, this study finds that the trends between the thalweg changes and riverbed deformation are similar, suggesting that both of these patterns are controlled by the same factors.

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Mississippi River Hydrodynamic and Delta Management Study (MRHDM) - Geomorphic Assessment

Cited by 16 publications

References 0 publications

Decadal‐Scale Riverbed Deformation and Sand Budget of the Last 500 km of the Mississippi River: Insights Into Natural and River Engineering Effects on a Large Alluvial River

Decadal‐Scale Riverbed Deformation and Sand Budget of the Last 500 km of the Mississippi River: Insights Into Natural and River Engineering Effects on a Large Alluvial River

Suspended sediment loads and tributary inputs into the Mississippi River below St. Louis, MO, 1990–2013 : A comparison with the Keown et al. (1981) report

Estimate of decadal‐scale riverbed deformation and bed‐load sediment transport during flood events in the lowermost Mississippi River

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