Textural analysis and modelling of a flood deposit: River severn, U.K.

Marriott, Susan B.

doi:10.1002/esp.3290170705

Cited by 118 publications

(82 citation statements)

References 11 publications

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“…Such approaches predict an exponential reduction in sedimentation with distance from the main channel, which is broadly consistent with field evidence [Marriott, 1992]. However, superimposed upon this general trend is a high level of spatial and temporal variability [Walling et al, 1996], which is a product of temporal variation in flood magnitude and sediment load, and the complex feedbacks between floodplain topography and sediment transport and deposition processes.…”

Section: Introductionsupporting

confidence: 60%

Development and evaluation of a new catchment‐scale model of floodplain sedimentation

Nicholas

Walling

Sweet

et al. 2006

Water Resources Research

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[1] Fine-sediment storage within floodplain systems typically represents a significant component of the catchment sediment budget and a primary control on sediment-associated nutrient and contaminant fluxes at the basin scale. However, quantitative modeling of floodplain sedimentation within whole catchments represents a significant challenge, not least because hydraulic controls on sediment transport and deposition processes operate at fine spatial scales that cannot be resolved by basin-scale models. This paper outlines a new approach to addressing this problem in order to develop a computationally efficient model of floodplain sedimentation, which retains a strong physical basis. The approach involves two stages. First, a simple theoretical model of overbank sedimentation is presented, which quantifies the relationship between floodplain geometry, overbank discharge, and total sedimentation rate. Second, the precise form that such a relationship should take is established by analysis of the output from high-resolution flow and suspended sediment transport models applied to 22 floodplain reaches along three U.K. rivers. This analysis supports a simple power law model between discharge in excess of bankfull and sedimentation rate per unit valley floor length per unit sediment concentration. The power law model is then incorporated within a sediment budget framework and implemented using a Monte Carlo approach to allow an assessment of uncertainty in the model parameterization. The relative likelihood of competing model structures is determined using estimates of mean annual floodplain sediment storage derived by analysis of the 137 Cs content of floodplain sediment cores. Comparison of 137 Cs-derived sedimentation rates with uncertainty-bounded model predictions highlights the potential for assessing the significance of overbank sedimentation within catchment sediment budgets using the simple power law model.

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Section: Introductionsupporting

confidence: 60%

Development and evaluation of a new catchment‐scale model of floodplain sedimentation

Nicholas

Walling

Sweet

et al. 2006

Water Resources Research

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“…In natural river systems, channel pattern (e.g., Eaton et al, 2010) and elevation changes driven by overbank deposition, subsidence, and aggradation may also influence the age structure of riverine POC. Since most overbank deposition is focused near the active channel (Pizzuto, 1987;Marriott, 1992;Aalto et al, 2008), the spatiotemporal pattern of lateral channel migration likely approximates the storage durations associated with these deposits. Overbank deposition distal to the channel coupled with subsidence can lead to the burial of sediment deposits below the scour depth of the migrating channel.…”

Section: Behavior Of Biogeochemical Cyclesmentioning

confidence: 99%

Model predictions of long-lived storage of organic carbon in river deposits

et al. 2017

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Abstract. The mass of carbon stored as organic matter in terrestrial systems is sufficiently large to play an important role in the global biogeochemical cycling of CO 2 and O 2 . Field measurements of radiocarbon-depleted particulate organic carbon (POC) in rivers suggest that terrestrial organic matter persists in surface environments over millennial (or greater) timescales, but the exact mechanisms behind these long storage times remain poorly understood. To address this knowledge gap, we developed a numerical model for the radiocarbon content of riverine POC that accounts for both the duration of sediment storage in river deposits and the effects of POC cycling. We specifically target rivers because sediment transport influences the maximum amount of time organic matter can persist in the terrestrial realm and river catchment areas are large relative to the spatial scale of variability in biogeochemical processes.Our results show that rivers preferentially erode young deposits, which, at steady state, requires that the oldest river deposits are stored for longer than expected for a well-mixed sedimentary reservoir. This geometric relationship can be described by an exponentially tempered power-law distribution of sediment storage durations, which allows for significant aging of biospheric POC. While OC cycling partially limits the effects of sediment storage, the consistency between our model predictions and a compilation of field data highlights the important role of storage in setting the radiocarbon content of riverine POC. The results of this study imply that the controls on the terrestrial OC cycle are not limited to the factors that affect rates of primary productivity and respiration but also include the dynamics of terrestrial sedimentary systems.

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“…Their for ma tion is likely re lated to tur bu lent ed dies, which are re spon si ble for sed i ment lift ing and trans fer ring from the chan nel to the near chan nel-bank zone. This mech a nism of sand trans port is de fined as the tur bulent dif fu sion of sus pended ma te rial (Pizzuto, 1987;Marriott, 1992;Asselman and Middelkoop, 1995) and pro duces rel atively thick sand ac cu mu la tion close to the chan nel.…”

Section: Discussion the Sedimentary Flood Recordmentioning

confidence: 99%

“…These field in ves ti ga tions of floodplain sed imen ta tion are ac com pa nied by nu mer ous lab o ra tory ex per iments (e.g., Bathurst et al, 2002;Fraselle et al, 2010) and numer i cal mod el ling (e.g., Marriott, 1992). These stud ies show that river flood sed i men ta tion is sig nif i cantly con di tioned by local fac tors and re mains poorly un der stood.…”

Section: Introductionmentioning

confidence: 86%

Sedimentary records of 2010 and 2011 Warta River seasonal floods in the region of Poznań, Poland

Skolasińska¹,

Szczuciński²,

Mitręga³

et al. 2014

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The Warta River near Poznañ (West Po land) rep re sents a me an der ing low land river mod i fied by hy dro-en gi neer ing pro jects. Re cently, two large floods oc curred dur ing the sum mer of 2010 and the win ter of 2011. Rapid re sponse sur veys were conducted to doc u ment ero sion and sed i men tary re cords of the floods (spa tial ex tent, grain size, com po si tion, grain microtextures). Fol low-up stud ies, which were con ducted dur ing the two years af ter the floods, as sessed postdepositional changes in the flood de pos its. A thick sand layer formed that ranged from an av er age of 10-15 cm (sum mer) to 30-35 cm (win ter), build ing nat u ral lev ees, side bars and cre vasse splays. The sand lay ers con sisted of fine-and me dium-grained sands that were well-sorted, fine skewed and sourced from the river chan nel. The lon ger but smaller win ter flood pro duced thicker and coarser de pos its at dif fer ent sites com pared with the sum mer flood. An or ganic-rich mud layer and al gal mats, which were short-ex ist ing, were also de tected on the floodplain. The study proved that the flood re cord on en gi neered rivers may be only in the sand bod ies near the river chan nel and their pres er va tion is mainly con trolled by their thick ness. A sin gle site may not re cord all floods, as par tic u lar events tend to leave de pos its in var i ous places.

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Textural analysis and modelling of a flood deposit: River severn, U.K.

Cited by 118 publications

References 11 publications

Development and evaluation of a new catchment‐scale model of floodplain sedimentation

Development and evaluation of a new catchment‐scale model of floodplain sedimentation

Model predictions of long-lived storage of organic carbon in river deposits

Sedimentary records of 2010 and 2011 Warta River seasonal floods in the region of Poznań, Poland

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