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Manh, N. V., B. Merz e H. Apel. "Sedimentation monitoring including uncertainty analysis in complex floodplains: a case study in the Mekong Delta". Hydrology and Earth System Sciences 17, n.º 8 (1 de agosto de 2013): 3039–57. http://dx.doi.org/10.5194/hess-17-3039-2013.
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Abstract. Quantity and quality of sediment deposition in complex floodplains are affected by many processes that are typically highly spatially and temporally variable and hard to quantify exactly. The main processes in this context are suspended sediment transport dynamics in rivers, floodplain channel interactions, and internal floodplain processes. In consequence, any point measurement of sedimentation in floodplains contains a high degree of uncertainty, both stemming from measurement errors and from the lack of representativeness for a larger area. However, up to now, uncertainty analyses have not been performed as part of publications on floodplain sedimentation data. Therefore the present work illustrates a field sampling strategy aiming at the monitoring of floodplain deposition and spatial variability on a large scale and at the quantification of uncertainties associated to sediment deposition data. The study was performed in the Mekong Delta, being an example for a large and complex floodplain with a high degree of anthropogenic disturbances. We present a procedure for the quantification of the uncertainty associated to the data, based on the design of the monitoring campaign, sampling procedures, and floodplain characteristics. Sediment traps were distributed strategically over the floodplain in clusters of three mat traps representing one monitoring point. The uncertainty originating from collection of the traps from still ponding water is quantified by lab experiments. The overall uncertainty of the deposition samples and the associated nutrient content is quantified in a Monte Carlo simulation and illustrated by uncertainty bounds. For the study area the results show a very high variability of the annual floodplain deposition (2.2–60 kg m−2) with uncertainty bounds ranging from −61 to +129% relative to overall mean deposition of 11.4 kg m−2. No correlations in the spatial distribution of sedimentation in the floodplains could be found. This is caused by the highly complex channel and dike system and the high number of hydraulic structures. Also, no differences in deposition between floodplain compartments protected with high and low dikes could be detected. However, it can be shown that within single floodplain compartments the spatial deposition variability depends on the dike levels and operation and location of hydraulic structures.
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Manh, N. V., B. Merz e H. Apel. "Sedimentation monitoring including uncertainty analysis in complex floodplains: a case study in the Mekong Delta". Hydrology and Earth System Sciences Discussions 10, n.º 1 (11 de janeiro de 2013): 325–73. http://dx.doi.org/10.5194/hessd-10-325-2013.
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Abstract. Quantity and quality of sediment deposition in complex floodplains are affected by many uncertain factors, ranging from suspended sediment transport dynamics in rivers and floodplain channel interactions to internal floodplain processes. In consequence, any point measurement of sedimentation in floodplains contains a high degree of uncertainty calling for a careful analysis of the measured data. However, uncertainty analyses are not documented in publications on floodplain sedimentation data. Therefore the presented work illustrates a field sampling strategy aiming at the quantification of uncertainties associated to sediment deposition data, as well as the spatial variability of sediments deposition on floodplains. The study was performed in the Mekong Delta (MD), being an example for a large and complex floodplain with a high degree of anthropogenic disturbances. We present a procedure for the quantification of the uncertainty associated to the data, based on the design of the monitoring campaign and floodplain characteristics. Sediment traps were distributed strategically over the floodplain in clusters of three mat traps representing one monitoring point. The uncertainty originating from collection of the traps in ponding water is quantified by lab experiments. The uncertainty of a single monitoring point is then quantified in a Monte Carlo simulation, propagating the uncertainty from the different uncertainty sources to final uncertainty bounds of the monitored sediment data. For the case study area, it is shown that there are no correlations in the spatial distribution of sedimentation in floodplains. This can be explained by the highly complex channel and dike system and the high number of hydraulic structures. However, it can be shown that within single floodplain compartments the spatial deposition variability depends on the dike levels and operation and location of hydraulic structures.
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Middelkoop, H. "Heavy-metal pollution of the river Rhine and Meuse floodplains in the Netherlands". Netherlands Journal of Geosciences - Geologie en Mijnbouw 79, n.º 4 (dezembro de 2000): 411–27. http://dx.doi.org/10.1017/s0016774600021910.
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AbstractThe embanked floodplains of the lower Rhine river in the Netherlands contain large amounts of heavy metals, which is a result of many years of deposition of contaminated overbank sediments. The metal pollution varies greatly between the various floodplain sections as well as in vertical direction within the floodplain soil profiles. The present contribution describes the key processes producing the spatial variability of the metal pollution in floodplain soils: (1) spatial patterns of the concentrations and deposition of Cd, Cu, Pb and Zn during a single flood, which have been determined from samples collected after a high-magnitude flood event; (2) the pollution trends of the lower Rhine over the past 150 years, which were reconstructed on the basis of metal concentrations in sediments from small ponds within the floodplain area. During the flood the largest metal depositions (0.03 g/m2 Cd, 0.7 g/m2 Cu, 1.1 g/m2 Pb and 5.0 g/m2 Zn for the Rhine) occurred along the natural levees, decreasing to about one third of these values at larger distance from the river. Deposition of heavy metals occurred since the end of the nineteenth century. Periods of maximum pollution occurred in the 1930s and 1960s, when Cu, Pb and Zn concentrations were about 6–10 times as high as background values.The resulting metal distribution in the floodplain soil profiles is illustrated by means of typical examples. Maximum metal concentrations in floodplain soils vary from 30 to 130 mg/kg for Cu, from 70 to 490 mg/kg for Pb, and from 170 to 1450 mg/kg for Zn. The lowest metal pollution is found in the distal parts of floodplain sections with low flooding frequencies, where average sedimentation rates have been less than about 5 mm/a. The largest metal accumulations occur in low-lying floodplain sections where average sedimentation rates have been more than 10 mm/a.
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Parker, Israel D., Roel R. Lopez, Reema Padia, Meghan Gallagher, Raghupathy Karthikeyan, James C. Cathey, Nova J. Silvy e Donald S. Davis. "Role of free-ranging mammals in the deposition of Escherichia coli into a Texas floodplain". Wildlife Research 40, n.º 7 (2013): 570. http://dx.doi.org/10.1071/wr13082.
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Context The role of wildlife in faecal pollution of water bodies (deposition of Escherichia coli (E. coli)) is not well understood. Current water-quality and land-use planning research largely relies on unreliable wildlife data (e.g. poor sourcing of abundance estimates, population density estimates applied to multiple fundamentally different areas, suspect or insufficiently described data collection techniques) Aims Our goal for the present research was to investigate deposition of E. coli into a floodplain by free-ranging mammals. Objectives of the research were to determine the density of important free-ranging meso- and large mammals in the study area, determine faecal E. coli loads for each species, and evaluate spatial data on species-specific faecal deposition. Methods We conducted our research in south-eastern Texas, USA, on two cattle ranches bisected by Cedar Creek (44-km long). Cedar Creek has elevated E. coli concentrations. We conducted mark–recapture and mark–resight population density estimates (2008/09) for meso- and large mammals in the study areas. We collected faecal samples from all captured wildlife. We also conducted transects through the study area to determine faecal-deposition patterns. Key results We found that raccoons (Procyon lotor), wild pigs (Sus scrofa), Virginia opossums (Didelphis virginiana) and white-tailed deer (Odocoileus virginianus) all had substantial faecal E. coli loads and population densities, thus implying an important role in E. coli deposition into the study floodplain. All species were widely distributed through the floodplain. Conclusions Free-ranging mammals contribute E. coli to floodplains and potentially affect water quality. We determined that four species commonly found in floodplains throughout North America all contributed E. coli to the study floodplain, thus implying mammal E. coli contributions in many locations and this is potentially important for E. coli management. Implications Improved locally specific mammal population estimates and estimates of locally derived E. coli concentration will improve floodplain and water-quality models that often depend on data of various quality. Additionally, our analyses demonstrated the need for continued research into the role of wildlife in E. coli deposition.
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Gordon, Brad A., Olivia Dorothy e Christian F. Lenhart. "Nutrient Retention in Ecologically Functional Floodplains: A Review". Water 12, n.º 10 (4 de outubro de 2020): 2762. http://dx.doi.org/10.3390/w12102762.
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Nutrient loads in fresh and coastal waters continue to lead to harmful algal blooms across the globe. Historically, floodplains—low-lying areas adjacent to streams and rivers that become inundated during high-flow events—would have been nutrient deposition and/or removal sites within riparian corridors, but many floodplains have been developed and/or disconnected. This review synthesizes literature and data available from field studies quantifying nitrogen (N) and phosphorus (P) removal within floodplains across North America and Europe to determine how effective floodplain restoration is at removing nutrients. The mean removal of nitrate-N (NO3−-N), the primary form of N in floodplain studies, was 200 (SD = 198) kg-N ha−1 year−1, and of total or particulate P was 21.0 (SD = 31.4) kg-P ha−1 year−1. Based on the literature, more effective designs of restored floodplains should include optimal hydraulic load, permanent wetlands, geomorphic diversity, and dense vegetation. Floodplain restorations along waterways with higher nutrient concentrations could lead to a more effective investment for nutrient removal. Overall, restoring and reconnecting floodplains throughout watersheds is a viable and effective means of removing nutrients while also restoring the many other benefits that floodplains provide.
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Thonon, I., H. Middelkoop e M. van der Perk. "The influence of floodplain morphology and river works on spatial patterns of overbank deposition". Netherlands Journal of Geosciences - Geologie en Mijnbouw 86, n.º 1 (abril de 2007): 63–75. http://dx.doi.org/10.1017/s0016774600021326.
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AbstractFloodplain topography and related hydraulic patterns of overbank flow constitute a major control on the amounts and patterns of sediment deposition on floodplains. We studied the differences in sediment deposition at two scales along two river branches of the lower River Rhine in the Netherlands: the Waal and IJssel River. Human alterations like levelling and embankment construction have severely impacted the floodplains along the Waal River branch (average discharge: 1500 m3·s‒1), whereas the relatively wide floodplains along the IJssel River (average discharge: 250 m3·s‒1) still exhibit their characteristic ridge-and-swale topography and natural levees. We found that, in general, the amounts of sediment deposited sediment decreases with increasing distance to the sediment source. Clay and organic matter content generally increase with decreasing floodplain elevation. These trends are, however, far less pronounced in the Waal River floodplains than in the IJssel River floodplains. Sediment deposited on the IJssel River floodplains also contains significantly more sand than the sediment deposited on the Waal River floodplains, probably because of the absence of minor embankments along the IJssel River and its higher sinuosity. Furthermore, during inundation the individual Waal River floodplains receive more sediment per unit area than the IJssel River floodplains. At the scale of the river branch, however, the conveyance losses in the Waal River are less than in the IJssel River, because of the larger surface area of the floodplains along the IJssel River relative to its water and sediment discharge during flood events. This discrepancy stresses that both the individual floodplain sections and the total river branch should be taken into account when studying the role of overbank deposition as part of a river’s sediment budget.
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Daskin, Joshua H., Filipe Aires e A. Carla Staver. "Determinants of tree cover in tropical floodplains". Proceedings of the Royal Society B: Biological Sciences 286, n.º 1914 (30 de outubro de 2019): 20191755. http://dx.doi.org/10.1098/rspb.2019.1755.
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Tree cover differentiates forests from savannas and grasslands. In tropical floodplains, factors differentiating these systems are poorly known, even though floodplains cover 10% of the tropical landmass. Seasonal inundation potentially presents trees with both challenges (soil anoxia) and benefits (moisture and nutrient deposition), the relative importance of which may depend on ecological context, e.g. if floods alleviate water stress more in more arid ecosystems. Here, we use remotely sensed data across 13 large tropical and sub-tropical floodplain ecosystems on five continents to show that climatic water balance (i.e. precipitation—potential evapotranspiration) strongly increases floodplain tree cover in interaction with flooding, fire and topography. As predicted, flooding increases tree cover in more arid floodplains, but decreases tree cover in climatically wetter ones. As in uplands, frequent fire reduced tree cover, particularly in wet regions, but—in contrast with uplands—lower elevation and sandier soils decreased tree cover. Our results suggest that predicting the impacts of changing climate, land use and hydrology on floodplain ecosystems depends on considering climate-disturbance interactions. While outright wetland conversion proceeds globally, additional anthropogenic activities, including alteration of fire frequencies and dam construction, will also shift floodplain tree cover, especially in wet climates.
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Yuskar, Yuniarti, Dewandra Bagus Eka Putra e Muhammad Revanda. "Quarternary Sediment Characteristics of Floodplain area: Study Case at Kampar River, Rumbio Area and Surroundings, Riau Province". Journal of Geoscience, Engineering, Environment, and Technology 3, n.º 1 (10 de março de 2018): 63. http://dx.doi.org/10.24273/jgeet.2018.3.1.1226.
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The study area is located in some floodplains of meandering river environment along the Kampar River, Rumbio. Typical morphology of meandering river that found in this area can be classified as stream channel, floodplain, abandoned channel, and sand bars deposit. Meandering river system carries sediment supply by suspended and bed - load (mixed load) in conjunction with low energy into a particular characteristic on sediment deposition. This study aims to determine the characteristics of the sediments, changes in vertical and lateral spread of sediment deposition on the floodplain environment. This study conducted by field survey using a hand auger of 1.5m - 4m depth and trenching which is a layer that has been exposed of 1-2 meters depth. Further analysis had been carried out using granulometri method and core data analysis to determine the characteristics and depositional facies. Sediment deposit that formed along the Kampar River is the result of the main channel migration of Kampar River. The characteristic of quaternary sediment facies is coarse to gravelly sand on the bottom followed by fine to very fine sand with pattern fining upwards and silt to clay and abundant terrestrial organic matter at the uppermost layer. Depositional facies are determined based on the characteristics of sediment facies which can be grouped into a stream channel, oblique accretion deposits, sand bars and overbank deposits.
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Azmi, Azyan Syahira, Mohd Suhaili Ismail, Jasmi Ab Talib e Nur Marina Samsudin. "Environment Of Deposition Of The Jurassic-Cretaceous Continental Deposit In Central Pahang (Peninsular Malaysia) By Sedimentary Facies Analysis". Bulletin Of The Geological Society Of Malaysia 70, n.º 1 (30 de novembro de 2020): 153–62. http://dx.doi.org/10.7186/bgsm70202013.
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Spatial lithofacies and lithofacies association serves as one of the reliable methods in assessing the depositional process of sediments and interpreting its depositional environment. The method of facies analysis is adapted in this study where four newly exposed stratigraphic sections along the Jerantut-Maran road in Jerantut, Central Pahang of Peninsular Malaysia were studied. Previous studies showed that the environment of deposition of these continental deposits is broadly of braided-meandering river. Sedimentological data from the newly exposed stratigraphic sections had given a better understanding on the sedimentation processes involved in these deposits where interpretation on the environment of deposition is construed up to its sub-environment. The main lithofacies recognized include conglomerate, sandstone, and fine-grained facies. The facies associations identified include (i) massive to laminated silt/mudstone, (ii) massive sandstone, (iii) thin to thick ripple to parallel laminated sandstone, (iv) conglomeratic sandstone, (v) graded channelized sandstone, (vi) coarsening upwards medium bedded sandstone and (vii) heterolithic sandstone. The different facies associations are grouped to four (4) facies assemblages showing characteristics of certain environment: (1) floodplain, (2) channel bar complex, (3) point bar and (4) crevasse splay. Floodplain facies assemblage is marked by fine-grained facies, mainly siltstone/mudstone and fine-grained sands with lower flow regime structures. Channel bar complex is identified by high energy deposits of coarse-to-medium grained sandstones often with scoured bottom and lenticular geometry. Point bar is recognized by the lateral accretion surfaces often consisting of normal graded sandstone with sharp top and bottom contact, sometimes capped with thin mudstones. Crevasse splay facies assemblage is characterized by heterolithic sandstone, dominated by flaser-wavy bedding and coarsening upwards medium bedded sandstone that is overlain by fine-grained facies of the floodplain assemblage. The overall facies based on an outcrop scale suggests general features of fluvial facies with fluctuations in flow energy. The environment of deposition is thus interpreted to be of braided river with floodplains and isolated point bar.
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Shaw, John D., Edmond C. Packee, Sr. e Chien-Lu Ping. "Growth of balsam poplar and black cottonwood in Alaska in relation to landform and soil". Canadian Journal of Forest Research 31, n.º 10 (1 de outubro de 2001): 1793–804. http://dx.doi.org/10.1139/x01-119.
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While constructing site index curves for balsam poplar (Populus balsamifera L.) and western black cottonwood (Populus trichocarpa Torr. & A. Gray) for interior and southcentral Alaska, we found variations in growth patterns that appeared to be related to landform and soil properties. We characterized soils for 42 of 65 site index plots in an attempt to explain site productivity variation. We found significant negative correlations between site index and elevation. Region, landform, and floodplain characteristics (especially sediment deposition) significantly affected poplar growth rate and soil development patterns. Nutrient availability and recycling appear to be mediated by flooding through scouring or burial of surface organic layers. Soil pH patterns related to O-horizon development and salt crust formation and dissolution described previously for the Tanana River floodplain do not hold for all floodplains in Alaska. At similar latitudes and elevations, upland locations may have higher site indices than frequently sedimented floodplain locations because upland soil development is relatively uninterrupted. Floodplain locations experiencing little or no sediment accumulation after establishment of poplar stands tend to have higher site indices than those experiencing frequent sediment accumulation. At some floodplain locations, site index was positively correlated with rooting depth.
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Waters, Michael R., e John C. Ravesloot. "Late Quaternary Geology of the Middle Gila River, Gila River Indian Reservation, Arizona". Quaternary Research 54, n.º 1 (julho de 2000): 49–57. http://dx.doi.org/10.1006/qres.2000.2151.
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Stratigraphy and dating provide an 18,000 yr record of erosion and deposition by the middle Gila River. Prior to 18,000 cal yr B.P., the Gila River cut into its floodplain and created a deep, wide channel. Sand and gravel accumulated within this channel until 4250–4400 cal yr B.P. By this time, the channel of the Gila River was narrow and deep. Around 5000 cal yr B.P., fine-grained sediments began to accumulate on the floodplain. At 800–950 cal yr B.P., there was a major period of channel widening. After this erosional episode, the channel again narrowed as it filled with sand and gravel until around 200 cal yr B.P. On the floodplain, deposition continued from about 5000 cal yr B.P. to 500 cal yr B.P. A period of stability and soil formation occurred on the floodplain between 500 and 200 cal yr B.P., after which overbank deposition resumed and buried the soil. Channel widening again occurred in the late 19th century. The changes observed in the sedimentologic history of the Gila River show that during the late Pleistocene, the Gila River was a competent stream capable of carrying and depositing coarse sediment loads. Later deposition of sand and gravel during the first half of the Holocene implies an increase in sediment yield from upstream watersheds. Changes during the last 4000 years reflect the response of the river to climatic perturbations, the timing of large floods, internal landscape thresholds, and human impacts.
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Notebaert, B., G. Houbrechts, G. Verstraeten, N. Broothaerts, J. Haeckx, M. Reynders, G. Govers, F. Petit e J. Poesen. "Fluvial architecture of Belgian river systems in contrasting environments: implications for reconstructing the sedimentation history". Netherlands Journal of Geosciences - Geologie en Mijnbouw 90, n.º 1 (agosto de 2011): 31–50. http://dx.doi.org/10.1017/s0016774600000652.
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AbstractAccurate dating is necessary to get insight in the temporal variations in sediment deposition in floodplains. The interpretation of such dates is however dependent on the fluvial architecture of the floodplain. In this study we discuss the fluvial architecture of three contrasting Belgian catchments (Dijle, Geul and Amblève catchment) and how this influences the dating possibilities of net floodplain sediment storage. Although vertical aggradation occurred in all three floodplains during the last part of the Holocene, they differ in the importance of lateral accretion and vertical aggradation during the entire Holocene. Holocene floodplain aggradation is the dominant process in the Dijle catchment. Lateral reworking of the floodplain sediments by river meandering was limited to a part of the floodplain, resulting in stacked point bar deposits. The fluvial architecture allows identifying vertical aggradation without erosional hiatuses. Results show that trends in vertical floodplain aggradation in the Dijle catchment are mainly related to land use changes. In the other two catchments, lateral reworking was the dominant process, and channel lag and point bar deposits occur over the entire floodplain width. Here, tracers were used to date the sediment dynamics: lead from metal mining in the Geul and iron slag from ironworks in the Amblève catchment. These methods allow the identification of two or three discrete periods, but their spatial extent and variations is identified in a continuous way. The fluvial architecture and the limitation in dating with tracers hampered the identification of dominant environmental changes for sediment dynamics in both catchments. Dating methods which provide only discrete point information, like radiocarbon or OSL dating, are best suited for fluvial systems which contain continuous aggradation profiles. Spatially more continuous dating methods, e.g. through the use of tracers, allow to reconstruct past surfaces and allow to reconstruct reworked parts of the floodplain. As such they allow a better reconstruction of past sedimentation rates in systems with important lateral reworking.
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Kronvang, Brian, Carl C. Hoffmann e Rianne Dröge. "Sediment deposition and net phosphorus retention in a hydraulically restored lowland river floodplain in Denmark: combining field and laboratory experiments". Marine and Freshwater Research 60, n.º 7 (2009): 638. http://dx.doi.org/10.1071/mf08066.
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Restoration of river systems allowing the transformation of former drained and dry riparian areas into riparian wetlands will increase the overbank storage of sediment and sediment-associated phosphorus (P). Wetland restoration is therefore a cost-effective mitigation measure to reduce the sediment and nutrient transport to river systems. The studied floodplain of the River Odense was restored in 2003 by remeandering the river channel along a 6-km reach. The restoration project involved 78 ha of riparian areas that were transformed from mainly arable land to extensive grassland and wetlands. The aim of the study was to quantify and model sediment and particulate P deposition on restored river floodplains. The present study suggests that during a 47-day flooding period, the river floodplain is able to retain 9–14.8% of the sediment and 1.1–3.7% of the particulate P transported in the river. Incubation experiments further showed that a maximum of 11–25% of the deposited phosphorus can be released as dissolved inorganic phosphorus following deposition. The results from the best deposition model (R2 = 0.42 for sediment and R2 = 0.44 for particulate P) show that work should be done to further improve the performance of these models.
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Walker, Alexander E., Johnnie N. Moore, Paul E. Grams, David J. Dean e John C. Schmidt. "Channel narrowing by inset floodplain formation of the lower Green River in the Canyonlands region, Utah". GSA Bulletin 132, n.º 11-12 (27 de março de 2020): 2333–52. http://dx.doi.org/10.1130/b35233.1.
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Abstract The lower Green River episodically narrowed between the mid-1930s and present day through deposition of new floodplains within a wider channel that had been established and/or maintained during the early twentieth century pluvial period. Comparison of air photos spanning a 74-yr period (1940–2014) and covering a 61 km study area shows that the channel narrowed by 12% from 138 ± 3.4 m to 122 ± 2.1 m. Stratigraphic and sedimentologic analysis and tree ring dating of a floodplain trench corroborates the air photo analysis and suggests that the initial phase of floodplain formation began by the mid-1930s, approximately the same time that the flow regime decreased in total annual and peak annual flow. Tamarisk, a nonnative shrub, began to establish in the 1930s as well. Narrowing from the 1940s to the mid-1980s was insignificant, because floodplain formation was approximately matched by bank erosion. Air photo analysis demonstrates that the most significant episode of narrowing was underway by the late 1980s, and analysis of the trench shows that floodplain formation had begun in the mid-1980s during a multi-year period of low peak annual flow. Air photo analysis shows that mean channel width decreased by ∼7% between 1993 and 2009. A new phase of narrowing may have begun in 2003, based on evidence in the trench. Comparison of field surveys made in 1998 and 2015 in an 8.5 km reach near Fort Bottom suggests that narrowing continues and demonstrates that new floodplain formation has been a very small proportion of the total annual fine sediment flux of the Green River. Vertical accretion of new floodplains near Fort Bottom averaged 2.4 m between 1998 and 2015 but only accounted for ∼1.5% of the estimated fine sediment flux during that period. Flood control by Flaming Gorge Dam after 1962 significantly influenced flow regime, reducing the magnitude of the annual snowmelt flood and increasing the magnitude of base flows. Though narrowing was initiated by changes in flow regime, native and nonnative riparian vegetation promoted floodplain formation and channel narrowing especially through establishment on channel bars and incipient floodplains during years of small annual floods.
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Japenga, J., K. H. Zschuppe, A. J. de Groot e W. Salomons. "Heavy metals and organic micropollutants in floodplains of the river Waal, a distributary of the river Rhine, 1958-1981." Netherlands Journal of Agricultural Science 38, n.º 3A (1 de setembro de 1990): 381–97. http://dx.doi.org/10.18174/njas.v38i3a.16595.
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During periods of high water discharge, dyke-protected floodplains of the river Rhine in the Netherlands become inundated and suspended matter from the river settles out. In the last 30 years, floodplain top layers have been sampled several times just after deposition; samples were dried and stored in a specimen bank. The samples were used to assess the development of sediment contamination with heavy metals and organic micropollutants during the past decades. Heavy metals studied include Zn, Cu, Cr, Pb, Cd, Ni, Hg and As. Different groups of chemically persistent organic micropollutants were studied: polycyclic aromatic hydrocarbons, polychlorobiphenyls, hexachlorobenzene, DDT and DDT-metabolites. The levels of most contaminants decreased substantially between 1958 and 1981. The variation among the different floodplain locations is due to differences in hydrodynamic characteristics of the location. A comparison was made between the concentrations found and the levels considered acceptable if the floodplain area is used for cattle grazing; a comparison was also made with estimated natural background levels and with reference values defined by the Dutch government. (Abstract retrieved from CAB Abstracts by CABI’s permission)
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Elznicová, Jitka, Tomáš Matys Grygar, Jan Popelka, Martin Sikora, Petr Novák e Michal Hošek. "Threat of Pollution Hotspots Reworking in River Systems: Case Study of the Ploučnice River (Czech Republic)". ISPRS International Journal of Geo-Information 8, n.º 1 (16 de janeiro de 2019): 37. http://dx.doi.org/10.3390/ijgi8010037.
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As fluvial pollution may endanger the quality of water and solids transported by rivers, mapping and evaluation of historically polluted fluvial sediments is an urgent topic. The Ploučnice River and its floodplain were polluted by local uranium mining from 1971–1989. We have studied this river since 2013 using a combination of diverse methods, including geoinformatics, to identify pollution hotspots in floodplains and to evaluate the potential for future reworking. Archival information on pollution history and past flooding was collected to understand floodplain dynamics and pollution heterogeneity. Subsequently, a digital terrain model based on laser scanning data and data analysis were used to identify the sites with river channel shifts. Finally, non-invasive geochemical mapping was employed, using portable X-ray fluorescence and gamma spectrometers. The resulting datasets were processed with geostatistical tools. One of the main outputs of the study was a detailed map of pollution distribution in the floodplain. The results showed a relationship between polluted sediment deposition, past channel shifts and floodplain development. We found that increased concentration of pollution occurred mainly in the cut-off meanders and lateral channel deposits from the mining period, the latter in danger of reworking (reconnecting to the river) in the coming decades.
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Rimkus, A., e S. Vaikasas. "Possible ways to improve sediment deposition in the Nemunas delta". Hydrology Research 41, n.º 3-4 (1 de abril de 2010): 346–54. http://dx.doi.org/10.2166/nh.2010.118.
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The deposition of sediment in the inundated floodplains of rivers, particularly in their deltas, improves the water quality of the rivers themselves and of their receivers. It would be very useful if ways to increase the amount of sediment deposition could be identified. An investigation into a number of possibilities was carried out in the delta of the River Nemunas. Various factors can influence the increase or decrease of sediment deposition, e.g. the increase of water discharge flowing through the river valley, the growth of bushes on the floodplain, the building of road banks across the valley and changes in growth stages of grass (which affect its ability to entrap sediments). The effects of these factors are discussed, and the most successful ways for improvement in the Nemunas delta are proposed. Similar methods may also be applicable in other river deltas.
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Valentin, GOLOSOV, BOTAVIN Dmitry, KONOPLEV Alexei e WAKIYAMA Yoshifumi. "Transformation of different reaches of the Niida River (Japan) after extreme flood". Revista de Geomorfologie 19, n.º 1 (30 de dezembro de 2017): 75–87. http://dx.doi.org/10.21094/rg.2017.006.
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Extreme floods can have different effects on the river bottom relief depending on several factors. The geomorphological impact of the extreme flood occurring in the Niida River basin (Fukushima prefecture, Honshu inland, Japan) on the channels and river bottom of different reaches of the river is analyzed. High-resolution satellite images and field assessments were used for quantitative evaluation of river bottom transformation which mainly occurred in the lower reach of the Niida river. The lower reach of the Niida River was divided on three subzones according the channel gradient changes. Each sub-zones is correspond with the dominance of a certain type of channel (straight, meandering and wandering). It was found that bank erosion exceeded in- channel deposition in 1,7-2,7 times for all types of river channel in the low reach located within the coastal floodplain. However, floodplain sedimentation is the most active processes for the river sections with meandering and wandering types of the river channel. Floodplain sedimentation exceed bank-erosion in 2.2 times for river sections with the meandering type of channel and in 2.9 time for the river sections with wandering type of channel. It was found that bank erosion exceeded in- channel deposition in 1,7-2,7 times for all types of river channel in the low reach located within the coastal floodplain. However, floodplain sedimentation is the most active processes for the river sections with meandering and wandering types of the river channel. Floodplain sedimentation exceed bankerosion in 2.2 times for river sections with the meandering type of channel and in 2.9 time for the river sections with wandering type of channel. The bank erosion exceeds floodplain deposition in 1,2 times only within the river sections with straight type of channel. Total sedimentation (in-channel + floodplain) in 2.6 times higher than bank erosion in the lower reach of the Niida River after extreme flood event with probability 4-5%.
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Nakanishi, T., S. Sato e T. Matsumoto. "TEMPORAL CHANGES IN RADIOCESIUM DEPOSITION ON THE FUKUSHIMA FLOODPLAIN". Radiation Protection Dosimetry 184, n.º 3-4 (26 de abril de 2019): 311–14. http://dx.doi.org/10.1093/rpd/ncz086.
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Abstract There has been significant concern about increases in the exposure dose in living areas due to the accumulation of radiocesium discharged from contaminated mountainous forests in Fukushima. In this study, we investigated the history of radiocesium deposition on several floodplains in Fukushima following the nuclear power plant accident. Radiocesium concentrations in river suspended particles and the air dose rates on the floodplains were observed continuously. The annual sediment accumulation on the floodplains was 5.5–200 kg m−2, and the observed radiocesium concentration decreased with the decrease in the radiocesium concentration of suspended particles. The air dose rates on the floodplains were gradually decreasing with time. In 2015, with heavy flood discharge, a sediment accumulation of 180–200 kg m−2 and a sharp decrease in the air dose rate were observed at the Takase River, which does not have a reservoir. Conversely, the sediment accumulation at the Ukedo River was significantly reduced due to deposition in an upstream reservoir.
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Madeira, Claudio Valdetaro, e Leonardo Borghi. "Estrutura dos depósitos sedimentares quaternários da bacia hidrográfica do rio Santana, Miguel Pereira, Estado do Rio de Janeiro". Anuário do Instituto de Geociências 22 (1 de janeiro de 1999): 8–22. http://dx.doi.org/10.11137/1999_0_8-22.
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The present work deals with stratigraphy, sedimentology and geomorphology of Quaternary sedimentary deposits of Santana river hydrographic basin. through facies and arquitectural elements descriptions. Based on five arquitectural elements characterized by ten lithofacies the following structural and depositional evolutions were scheduled: 1) formation of thick soil horizons over the basement; 2) deposition of several alluvial fans on the soils (lithofacies Gm and Fm, element E); 3) above an unconformity we can recognize a fluvial system, characterized by a non well drainage floodplain. This floodplain is overlaid by high-sinuosity channels (lithofacies Sp and St, element C) genetically related to other floodplain (lithofacies Fl and Fsc, element A) where the interfigering with crevasse splay deposits (lithofacies Sh, Sl, and Sp, element B) is ususal; 4) an erosional phase suceed by a new depositional phase characterized by low-sinuosity channels (lithofacies Gp, Gt, Sp, St, and Sh, element D). Nowadays anthropogenic action produces a new erosional phase. The geomorphological features recognized were scheduled: 1) the present floodplain 1.5m above the river bed; 2) the low terrace ( named T2) 5m above the river bed and its deposits is related to element D; 3) the high terrace ( named T1) 11m above the river bed and its deposits is related to elements A, B, C and E.
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IZUMI, Norihiro, Yukiko MATSUDA e Hitoshi TANAKA. "FINE SAND DEPOSITION ON A FLOODPLAIN DURING A FLOOD". PROCEEDINGS OF HYDRAULIC ENGINEERING 44 (2000): 419–24. http://dx.doi.org/10.2208/prohe.44.419.
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Wang, H., e X. Jia. "Selective deposition response to aeolian-fluvial sediment supply in the desert braided channel of the Upper Yellow River, China". Natural Hazards and Earth System Sciences Discussions 3, n.º 2 (10 de fevereiro de 2015): 1269–90. http://dx.doi.org/10.5194/nhessd-3-1269-2015.
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Abstract. Rivers flow across aeolian dunes and develop braided stream channels. Both aeolian and fluvial sediment supplies regulate sediment transport and deposition in such a cross-dune braided river. Here we show a significant selective deposition in response to both aeolian and fluvial sediment supplies in the Ulan Buh desert braided channel. This selective deposition developed by the interaction between the flows and the Aeolian-fluvial sediment supplies, making the coarser sediments (> 0.08 mm) from aeolian sand supply and bank erosion to accumulate in the channel center and the finer fluvial sediments (< 0.08 mm) to be deposited on the bar and floodplain surfaces and forming a coarser-grained thalweg bed bounded by finer-grained floodplain surfaces. This lateral selective deposition reduces the downstream sediment transport and is a primary reason for the formation of "above-ground river" in the braided reach of the Upper Yellow River in response to aeolian and fluvial sediment supplies.
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Aalto, Rolf, e Charles A. Nittrouer. "210 Pb geochronology of flood events in large tropical river systems". Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 370, n.º 1966 (13 de maio de 2012): 2040–74. http://dx.doi.org/10.1098/rsta.2011.0607.
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Floodplain sedimentation removes particles from fluvial transport and constructs stratigraphic records of flooding, biogeochemical sequestration and other aspects of the environmental history of river basins—insight that is enhanced by accurate geochronology. The natural fallout radionuclide 210 Pb, often employed to date lacustrine and marine sediments, has previously been used to determine floodplain accumulation rates over decadal-to-century time scales using the assumption that both input concentration and sediment accumulation rates are constant. We test this model in approximately 110 cores of pristine floodplains along approximately 2000 km of the Rios Beni and Mamore in northern Bolivia; over 95 per cent of the 210 Pb profiles depict individual episodic deposition events, not steady-state accumulation, requiring a revised geochronological methodology. Discrete measurements of down-core, clay-normalized adsorbed excess 210 Pb activity are coupled with a new conceptual model of 210 Pb input during floods: constant initial reach clay activity, unknown sedimentation (CIRCAUS). This enhanced methodology yields 210 Pb dates that correspond well with (i) dates determined from meteoric caps, (ii) observed dates of river bar formation, (iii) known flood dates, and (iv) dates from nearby cores along the same transect. Similar results have been found for other large rivers. The CIRCAUS method for geochronology therefore offers a flexible and accurate method for dating both episodic (decadal recurrence frequency) and constant (annual recurrence) sediment accumulation on floodplains.
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Wilson, C. G., A. N. T. Papanicolaou e O. Abaci. "SOM dynamics and erosion in an agricultural test field of the Clear Creek, IA watershed". Hydrology and Earth System Sciences Discussions 6, n.º 2 (4 de março de 2009): 1581–619. http://dx.doi.org/10.5194/hessd-6-1581-2009.
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Abstract. To date, few studies have examined in detail the role of spatial variabilities of erosion on Soil Organic Matter (SOM). More specifically, the role of deposition is still poorly understood. The nature of the research is novel because it combines dynamic model simulations using the Water Erosion Prediction Project (WEPP) and CENTURY SOM dynamics model to evaluate soil and SOM loss in an agricultural test field of the Clear Creek, IA watershed. In addition, numerical simulations were coupled with limited field investigations calibrating and verifying WEPP and CENTURY. The main task of this study was to evaluate changes in SOM dynamics in a field using CENTURY and accounting for the interdependence of historical and current management practices, erosion (i.e., soil loss and deposition), and decomposition. Simulations were conducted under three different erosion scenarios determined using WEPP to demonstrate the importance of including deposition in studies of SOM dynamics: (1) assuming no erosion, (2) using an average erosion rate for the whole field, and (3) dividing the field into an erosional upland and depositional floodplain. The total SOM concentrations produced by the segmented field simulation agreed best with the measured field values. Simulated SOM concentrations values for the upland were 13% lower and values for the floodplain were 16% higher than measured field values. The results of this investigation compare well with the simulation results of other studies in terms of the effects of deposition on SOM distributions and that more detailed erosion values lead to better performance of the model. Deposition decreased SOM loss from the field by accounting for sequestration of carbon.
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Buchheim, H. P., L. R. Brand e H. T. Goodwin. "Lacustrine to fluvial floodplain deposition in the Eocene Bridger Formation". Palaeogeography, Palaeoclimatology, Palaeoecology 162, n.º 1-2 (setembro de 2000): 191–209. http://dx.doi.org/10.1016/s0031-0182(00)00112-7.
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González-Sanchis, M., J. Murillo, A. Cabezas, J. E. Vermaat, F. A. Comín e P. García-Navarro. "Modelling sediment deposition and phosphorus retention in a river floodplain". Hydrological Processes 29, n.º 3 (17 de fevereiro de 2014): 384–94. http://dx.doi.org/10.1002/hyp.10152.
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Omengo, Fred Ochieng, Tine Alleman, Naomi Geeraert, Steven Bouillon e Gerard Govers. "Sediment deposition patterns in a tropical floodplain, Tana River, Kenya". CATENA 143 (agosto de 2016): 57–69. http://dx.doi.org/10.1016/j.catena.2016.03.024.
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Baniya, Mahendra B., Takashi Asaeda, Takeshi Fujino, Senavirathna M. D. H. Jayasanka, Guligena Muhetaer e Jinghao Li. "Mechanism of Riparian Vegetation Growth and Sediment Transport Interaction in Floodplain: A Dynamic Riparian Vegetation Model (DRIPVEM) Approach". Water 12, n.º 1 (24 de dezembro de 2019): 77. http://dx.doi.org/10.3390/w12010077.
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The ecological dynamics of riparian areas interact with sediment transport in river systems, which plays an active role in riparian vegetation growth in the floodplain. The fluvial dynamics, hydraulics, hydro-meteorological and geomorphological characteristics of rivers are associated with sediment transport in river systems and around the riparian area. The flood disturbance, sediment with nutrients and seeds transported by river, sediment deposition, and erosion phenomena in the floodplain change the bare land area to vegetation area and vice versa. The difference in riparian vegetation area in the river floodplain is dependent on the sediment grain size distribution which is deposited in the river floodplain. Mathematical models describing vegetation growth in a short period exist in literature, but long-term modelling and validations are still lacking. In order to cover long-term vegetation growth modelling, a Dynamic Riparian Vegetation Model (DRIPVEM) was proposed. This paper highlights the existing modelling technique of DRIPVEM coupled with a Dynamic Herbaceous Model used to establish the interactive relationship of sediment grain sizes and riparian vegetation in the floodplain.
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Wang, H., X. Jia, Y. Li e W. Peng. "Selective deposition response to aeolian–fluvial sediment supply in the desert braided channel of the upper Yellow River, China". Natural Hazards and Earth System Sciences 15, n.º 9 (2 de setembro de 2015): 1955–62. http://dx.doi.org/10.5194/nhess-15-1955-2015.
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Abstract. Rivers flow across aeolian dunes and develop braided stream channels. Both aeolian and fluvial sediment supplies regulate sediment transport and deposition in such cross-dune braided rivers. Here we show a significant selective deposition in response to both aeolian and fluvial sediment supplies in the Ulan Buh desert braided channel. The Ulan Buh desert is the main coarse sediment source for this desert braided channel, and the mean percentage of the coarser (> 0.08 mm) grains on the aeolian dunes surface is 95.34 %. The lateral selective deposition process is developed by the interaction between the flows and the aeolian–fluvial sediment supplies, causing the coarser sediments (> 0.08 mm) from aeolian sand supply and bank erosion to accumulate in the channel centre and the finer fluvial sediments (< 0.08 mm) to be deposited on the bar and floodplain surfaces, forming a coarser-grained thalweg bed bounded by finer-grained floodplain surfaces. This lateral selective deposition reduces the downstream sediment transport and is a primary reason for the formation of an "above-ground" river in the braided reach of the upper Yellow River in response to aeolian and fluvial sediment supplies.
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Hostache, R., C. Hissler, P. Matgen, C. Guignard e P. Bates. "A 2-D hydro-morphodynamic modelling approach for predicting suspended sediment propagation and related heavy metal contamination in floodplain: a sensitivity analysis". Hydrology and Earth System Sciences Discussions 11, n.º 2 (10 de fevereiro de 2014): 1741–76. http://dx.doi.org/10.5194/hessd-11-1741-2014.
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Abstract. Fine sediments represent an important vector of pollutant diffusion in rivers. When deposited in floodplains and riverbeds they can be responsible for soil pollution. In this context, this paper proposes a hydro-morphodynamic modelling exercise aiming at predicting transport and diffusion of fine sediments and dissolved pollutants. The model is based upon the Telemac hydro-informatic system (dynamical coupling Telemac-2D-Sysiphe). As empirical and semi-empirical parameters need to be calibrated for such a modelling exercise, a sensitivity analysis is proposed. In parallel to the modelling exercise, an extensive hydrological/geochemical database has been set up during two flood events. The main sensitive parameters were found to be the hydraulic friction coefficient and the sediment particle settling velocity in water. Using the two monitored hydrological events as calibration and validation, it was found that the model is able to satisfyingly predict suspended sediment and dissolve pollutant transport in the river channel. In addition, a qualitative comparison between simulated sediment deposition in the floodplain and a soil contamination map shows that the preferential zones for deposition identified by the model are realistic.
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Nicholas, A. P., e D. E. Walling. "Numerical modelling of floodplain hydraulics and suspended sediment transport and deposition". Hydrological Processes 12, n.º 8 (30 de junho de 1998): 1339–55. http://dx.doi.org/10.1002/(sici)1099-1085(19980630)12:8<1339::aid-hyp618>3.0.co;2-6.
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Talchabhadel, Rocky, Hajime Nakagawa e Kenji Kawaike. "Sediment management in tidal river: A case study of East Beel Khuksia, Bangladesh". E3S Web of Conferences 40 (2018): 02050. http://dx.doi.org/10.1051/e3sconf/20184002050.
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The widespread construction of coastal embankments limited the natural deposition on the floodplain and accelerated the silt deposition in river channels. It resulted in drainage congestion and large-scale waterlogging problem. The temporary de-poldering is one of the effective methods to solve this issue. During high tide, muddy water enters the selected tidal basin depositing a major portion of sediment and at low tide, relatively clearer water erodes the riverbed. This paper presents a twodimensional numerical model to simulate the mechanism of sediment transport and deposition during the process of controlled flooding. The model was applied to three different scenarios of the embankment cuts in East beel Khuksia, Bangladesh. The study recommends operating single embankment cut at a time if the tidal equilibrium is fulfilled by the opening size of that embankment cut. The developed model can be used to assess the land heightening in sediment-starved tidal basins and ultimately plan the rotation of tidal basins for sustainable sediment management.
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Hereford, Richard. "Modern Alluvial History of the Paria Rver Drainage Basin, Southern Utah". Quaternary Research 25, n.º 3 (maio de 1986): 293–311. http://dx.doi.org/10.1016/0033-5894(86)90003-7.
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Stream channels in the Paria River basin were eroded and partially refilled between 1883 and 1980. Basin-wide erosion began in 1883; channels were fully entrenched and widened by 1890. This erosion occurred during the well-documented period of arroyo cutting in the Southwest. Photographs of the Paria River channel taken between 1918 and 1940 show that the channel did not have a floodplain and remained wide and deep until the early 1940s. A thin bar (<50 cm), now reworked and locally preserved, was deposited at that time. Basin-wide aggradation, which began in the early 1940s, developed floodplains by vertical accretion. The floodplain alluvium, 1.3–3 m thick. consists of two units recognizable throughout the studied area. An older unit was deposited during a time of low flow and sediment yield whereas the younger unit was deposited during times of high flow, sediment yield, and precipitation. Tree-ring dating suggests that the older unit was deposited between the early 1940s and 1956, and the younger between 1956 and 1980. The units are not time transgressive, suggesting that deposition by knickpoint recession was not an important process. High peak-flood discharges were associated with crosion and low flood discharges with aggradation. The erosional or aggradational mode of the streams was determined principally by peak-flood discharge, which in turn was controlled by precipitation.
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Wierzbicki, Grzegorz, Piotr Ostrowski e Tomasz Falkowski. "Applying floodplain geomorphology to flood management (The Lower Vistula River upstream from Plock, Poland)". Open Geosciences 12, n.º 1 (14 de outubro de 2020): 1003–16. http://dx.doi.org/10.1515/geo-2020-0102.
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AbstractUsing remote sensing extended on geological and topographical maps and verified by the field work, we present the flood management and study the geomorphic features of the floodplain of a large, sand bed, untrained but embanked river in order to determine the flood hazard and to predict future flood scenarios. In geomorphological mapping, we focus on the landforms: crevasse channels and splays, flood basin, chute channels, side arms, floodplain channels, dunes and fields of aeolian sand. We base the flood risk assessment on consultations with environmental engineers who design new technical structures that control inundation (cut-off walls and lattice levees). We describe a levee breach as a result of piping (inner erosion) in a high hydraulic gradient condition and its effect (scour hole) as an erosional landform consistent with the repetitive pattern of erosion and deposition formed by an overbank flow on a floodplain. We reveal an existence of homogenous morphodynamic reaches in the river valley.
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Olde Venterink, Harry, Jan E. Vermaat, Mario Pronk, Frank Wiegman, Guda E. M. van der Lee, Martin W. van den Hoorn, L. W. G. Bert Higler e Jos T. A. Verhoeven. "Importance of sediment deposition and denitrification for nutrient retention in floodplain wetlands". Applied Vegetation Science 9, n.º 2 (novembro de 2006): 163–74. http://dx.doi.org/10.1111/j.1654-109x.2006.tb00665.x.
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Govenor, Heather, W. Cully Hession, Tyler A. Keys, C. Nathan Jones, Ryan D. Stewart e Leigh-Anne H. Krometis. "Evaluating Rare Earth Elements as Tracers of Fluvial Processes: Fine Sediment Transport and Deposition in a Small Stream". Transactions of the ASABE 64, n.º 3 (2021): 905–18. http://dx.doi.org/10.13031/trans.14358.
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HighlightsNatural sediments labeled with rare earth elements can effectively be used as tracers for quantifying fine sediment transport and deposition.Two artificial floods in a small stream (100 ha watershed, 1.5 year return flow of 515 L s-1) transported fine sediment 0 m to >850 m at a maximum flow rate of 55 L s-1.Sediment deposition per unit area was greater in the channel than in the near-channel floodplain.Use of two distinct tracers demonstrated resuspension extent during sequential high-flow events.Presence of large wood in the channel was associated with reduced streamflow rate, decreased suspended sediment transport velocity, increased channel sediment deposition, and reduced near-floodplain sediment deposition.Abstract. Effective sediment management requires an understanding of the lag time between best management practice implementation and observable changes in the target water body. To improve our understanding of sediment lag times, we tested a method to label locally sourced sediments with rare earth elements to quantify fine sediment flow-through and storage in fluvial systems. We injected sediments labeled with lanthanum and ytterbium into a small stream during two artificial flood events. During the floods, we collected and quantified suspended sediments and sediment deposition in the stream channel and floodplain at four cross-sections within our study reach. Two down-gradient (90 m and 850 m) time-integrated suspended sediment samplers evaluated total travel distance. Sediment tracer observations of particle transport distances ranged from 0 m to at least 850 m at a maximum flow rate of 55 L s-1 (stream 1.5 year flow was 515 L s-1). Sediment deposition per unit area was greater in the channel than in the floodplain. The majority of sediment tracer mass injected into the stream entered storage within the first 69 m of the reach. Some particles that deposited following the first flood were resuspended and either transported downstream or redeposited within the study reach. Our results support the further use of rare earth elements as sediment tracers to inform water quality and sediment transport models, and to provide estimates of lag times between management actions and downstream improvements. Keywords: Fine sediment, Flood, Fluvial geomorphology, Lag time, Large wood, Rare earth elements, Sediment deposition, Sediment transport, Tracer.
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Erturaç, Mehmet Korhan, Eren Şahiner, Cengiz Zabcı, Hilal Okur, Georgios S. Polymeris, Niyazi Meriç e Cercis İkiel. "Fluvial response to rising levels of the Black Sea and to climate changes during the Holocene: Luminescence geochronology of the Sakarya terraces". Holocene 29, n.º 6 (11 de março de 2019): 941–52. http://dx.doi.org/10.1177/0959683619831428.
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The Sakarya River is among the largest fluvial systems of the southern Black Sea basin, draining most of NW Anatolia. The river crosses the high relief of the Pontide mountain range through successive narrow gorges and strike-slip basins formed by the North Anatolian Fault (NAF) System. We have investigated this fluvial record along the course of the main river channel at its lower reaches. The study site is located south of the Adapazarı Basin, ~50 km inland from the Black Sea, where remnant floodplains are preserved as a three-step terrace staircase resulting from continuous uplift to the south of the NAF. The combination of high resolution mapping with a detailed luminescence (OSL and p-IR-IRSL) and radiocarbon geochronology has shed light on changes in the level of the Black Sea and in the hydrological system during the late Pleistocene to recent. The last glacial period is represented by the highest terrace (T3) indicating deposition during marine isotope stage (MIS) 3 in between two low stands of the Black Sea. Following a long-term erosional period initiated prior to last glacial maximum (LGM), the initiation of the deposition (T2) was synchronous with the proposed catastrophic sea level rise of the Black Sea (cal. C14 9.3 ka BP) which continued throughout the Holocene until the Roman warm period (1.8 ka BP). The late-Holocene to recent morphological evolution of the region is marked with two sequential erosional and depositional (T1 and T0) periods, which can be correlated with the well-documented historical climate shifts affecting the hydrological system. These results reveal that the erosional and depositional periods on the Sakarya River floodplain are controlled by major sea level changes and climatically induced fluctuations in discharge and sediment supply.
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Vaikasas, Saulius, e Alfonsas Rimkus. "Hydraulic Modelling of Suspended Sediment Deposition in an Inundated Floodplain of the Nemunas Delta". Hydrology Research 34, n.º 5 (1 de outubro de 2003): 519–30. http://dx.doi.org/10.2166/nh.2003.0022.
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Floods of meadows in the delta of the river Nemunas contribute to the deposition and retention of sediments and nutrient that would otherwise deposit in the Curonian Lagoon. In grassland area of the Nemunas delta the formation of alluvial soil occurs according to the flood dynamic rules: water discharging into the valley leaves suspended sediments on the soil surface. By mathematical modelling it was established that about 35% of suspended sediments inflow deposited there. Due to sand particles deposited during the study period (1950-1991), the natural river bank levee rose by 0.3 m. Fine clay and silt particles deposited uniformly within the entire model area and formed a 4-6 mm thick layer there. It contained about 50-60 t/ha of silt deposits. The valley soils were naturally fertilized with 250 t of potassium, 950 t of phosphorus, 38,000 t of calcium, and even 147,000 t of organic matter saturated with nitrogen. Certain amount of heavy metals also deposited there. The deposition process has not yet been adequately investigated under the conditions of flow bed covered by grass. It was established that grass cover intensified the sediment deposition in the floodplain. Considering calculation results and measurement data, the process of suspended sediment deposition was analysed and new formulas were derived. It was established that in order to increase sedimentation in the valley, it would be necessary to increase water discharge overflowing from river bed into the delta valley.
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Bakker, M. A. J., D. Maljers e H. J. T. Weerts. "Ground-penetrating radar profiling on embanked floodplains". Netherlands Journal of Geosciences - Geologie en Mijnbouw 86, n.º 1 (abril de 2007): 55–61. http://dx.doi.org/10.1017/s0016774600021314.
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AbstractManagement of the Dutch embanked floodplains is of crucial interest in the light of a likely increase of extreme floods. One of the issues is a gradual decrease of floodwater accommodation space as a result of overbank deposition of mud and sand during floods. To address this issue, sediment deposits of an undisturbed embanked floodplain near Winssen along the river Waal were studied using ground-penetrating radar (GPR). A number of radar facies units were recognized. Boreholes were used to relate radar facies units to sedimentary facies and to determine radar velocity. The GPR groundwave is affected by differences in moisture and texture of the top layer and probably interferes with the first subsurface reflector. The architectural elements recognized in the GPR transects confirm earlier reported insights on human-influenced river behaviour. This is testified in the development of sand bars during flood regimes that are probably more widespread than previously established.
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Liu, Fei, e Xiao Feng Zhang. "Experimental Study on River Channel's Formation and Change Process of on the Surface of Delta Deposition". Applied Mechanics and Materials 405-408 (setembro de 2013): 2264–72. http://dx.doi.org/10.4028/www.scientific.net/amm.405-408.2264.
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Experimental study on river channels formation and change process with two different constant flows 2.45L/s and 4.9L/s that which come from mountains and into delta depositions surface, based on sediment supply 15.72kg/h at the water inlet. After 964h experiment, research on the study shows as follows: with 2.45L/s flow, on the surface of delta depositions forming process the channel appears as straight, braided, micro-bend and meandering form. The first formation processes of delta deposition are straight and braided river which appeared alternately every 50h on the surface. When time goes on the delta get longer and braided streams branch of the shunt decrease gradually, that made the channel appeared with slightly curved form. Combined with that flexural radius gets bigger because of the outer bank erosion of slightly curved channel backed off, finally the meandering channels presented. With 4.9L/s flow, the formation processes gave priority of braided river, which appeared every 15h cycle, following the aggravate of eroding in floodplain and scouring in main channel, the river pool board-shallow comes with the main-flow swing, the channel existed as slightly curved form, and appears two sides of deposition. Finally analysis and research the channel cross-section morphological and longitudinal slope. In conclusion, the delta depositions surface channel existed as micro-bend of no branch with single strands, under the constantly water and sediment conditions.
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Shen, Zhixiong, Torbjörn E. Törnqvist, Barbara Mauz, Elizabeth L. Chamberlain, Austin G. Nijhuis e Laure Sandoval. "Episodic overbank deposition as a dominant mechanism of floodplain and delta-plain aggradation". Geology 43, n.º 10 (21 de agosto de 2015): 875–78. http://dx.doi.org/10.1130/g36847.1.
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Nakayama, Naoki, Jun Nishihiro, Yuichi Kayaba, Takashi Muranaka e Izumi Washitani. "Seed deposition of Eragrostis curvula, an invasive alien plant on a river floodplain". Ecological Research 22, n.º 4 (5 de outubro de 2006): 696–701. http://dx.doi.org/10.1007/s11284-006-0047-3.
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Nakayama, Naoki, Jun Nishihiro, Yuichi Kayaba, Takashi Muranaka e Izumi Washitani. "Seed deposition of Eragrostis curvula, an invasive alien plant on a river floodplain". Ecological Research 22, n.º 4 (13 de fevereiro de 2007): 702. http://dx.doi.org/10.1007/s11284-007-0346-3.
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Latuso, Karen D., Richard F. Keim, Sammy L. King, David C. Weindorf e Ronald D. DeLaune. "Sediment deposition and sources into a Mississippi River floodplain lake; Catahoula Lake, Louisiana". CATENA 156 (setembro de 2017): 290–97. http://dx.doi.org/10.1016/j.catena.2017.04.020.
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Forbes, Matt, Erick Bestland e Rod Wells. "Preliminary 14C Dates on Bulk Soil Organic Matter from the Black Creek Megafauna Fossil Site, Rocky River, Kangaroo Island, South Australia". Radiocarbon 46, n.º 1 (2004): 437–43. http://dx.doi.org/10.1017/s0033822200039746.
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Radiocarbon age determinations and stratigraphy suggest that the deposits in Black Creek Swamp on Kangaroo Island record 3 phases of deposition and associated soil development which spanned at least the last 20,000 yr. Four new 14C age determinations on bulk soil organic matter and their stratigraphic context are presented in this paper. Three of these age determinations (FP6: 15,687 ± 110 BP [WK11487]; FP7: 16,326 ± 385 BP [WK11488]; and FP8: 17,618 ± 447 BP [WK11489]), are from the organic-rich fossil layer located 45–75 cm below the current floodplain surface. The fourth, a much younger date, FP5: 5589 ± 259 BP (WK11486), was obtained from the base of the overlying modern soil. The dates for the fossil layer increase systematically with depth and correlate well with 5 previous 14C dates (Hope et al., unpublished), ranging between 15,040 ± 120 BP and 19,000 ± 310 BP. This suggests that the data set represents a possible minimum age of the bulk organic matter, and considering the high organic matter contents of approximately 8%, has implications for the age of the megafauna buried in this layer. The overlying modern soil, with its much younger date, contains lower levels of organic matter (3–7%) and gastropods not seen in the fossil layer. This suggests a substantial change in environmental conditions probably due to an alteration in the floodplain drainage conditions. This chronological and sedimentalogical discontinuity indicates that 2 distinct depositional regimes existed and were separated by up to 10,000 14C yr. A calcareous, sandy silt deposit underlying the fossil layer is a calcarenite deposit with low total organic content and is considered the base of the section; it suggests a third separate depositional episode. As such, the Black Creek Swamp in the southwest corner of Kangaroo Island formed intermittently over at least the last 20,000 yr during 3 distinct depositional phases, one of which was the formation of the fossil-laden, organic-rich floodplain surface, which has a possible minimum age of approximately 15,000 to 19,000 BP.
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Wyżga, Bartłomiej. "Estimating mean flow velocity in channel and floodplain areas and its use for explaining the pattern of overbank deposition and floodplain retention". Geomorphology 28, n.º 3-4 (julho de 1999): 281–97. http://dx.doi.org/10.1016/s0169-555x(98)00110-x.
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Rasmussen, Dirk M., Brady Z. Foreman, Henry C. Fricke, Kathryn Snell, Lindsey Gipson e Bernard Housen. "The early Paleogene stratigraphic evolution of the Huerfano Basin, Colorado". Rocky Mountain Geology 55, n.º 1 (1 de julho de 2020): 1–26. http://dx.doi.org/10.24872/rmgjournal.55.1.1.
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ABSTRACT Sedimentary basins throughout the North American Western Interior contain a record of Late Cretaceous through Eocene deposition related to the Laramide orogeny. The typical stratigraphic progression includes an uppermost Cretaceous fluvio-deltaic geologic formation that is unconformably overlain by an alluvial or paludal Paleocene geologic formation. The Paleocene unit is usually characterized by drab overbank facies, and overlain by an interval of amalgamated fluvial sand bodies. The overlying Eocene geologic units are characterized by red bed overbank facies. These major stratigraphic changes have been variably linked to long-wavelength dynamic subsidence, local uplift, and climatic shifts. Herein, we evaluate the depositional history of the Huerfano Basin of south-central Colorado in this overarching context. Our study presents a detailed lithofacies analysis of the Poison Canyon, Cuchara, and Huerfano Formations integrated with a new bulk (1) organic carbon isotope record, n = 299 measurements (Data Supplement 1A); and (2) magnetic record, n = 247 measurements (Data Supplement 1B). We interpret that the Paleocene Poison Canyon Formation was deposited by a braided or coarse-grained meandering river system with relatively poorly drained floodplains. The Eocene Huerfano Formation was likely deposited by a coarse-grained meandering river system with a comparatively well-drained floodplain. This pattern mirrors other Laramide basins, and is likely related to a regional drying pattern linked to long-term warming during the early Paleogene. Age of the intervening Cuchara Formation is poorly resolved, but is an anomalously thick and coarse-grained fluvial unit, with evidence for extensive reworking of floodplain deposits and a moderate coarsening-upward pattern. The Cuchara Formation is associated with magnetic trends that suggest greater oxidation and weathering, and greater variability in rainfall patterns, as well as a subtle negative shift in carbon isotope values. This pattern indicates a period of widespread progradation within the basin, potentially related to a major Laramide uplift event that affected Colorado’s Wet Mountains, Front Range, and Sangre de Cristo Mountains.
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Wood, S. H., e A. D. Ziegler. "Floodplain sediment from a 30-year-recurrence flood in 2005 of the Ping River in northern Thailand". Hydrology and Earth System Sciences Discussions 4, n.º 5 (18 de outubro de 2007): 3839–68. http://dx.doi.org/10.5194/hessd-4-3839-2007.
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Abstract. This paper documents the nature of flood-producing storms and floodplain deposition associated with the 28 September–2 October 2005 30-year-recurrence flood on the Ping River in northern Thailand. The primary purpose of the study is to understand the extent that deposits from summer-monsoon floods can be identified in floodplain stratigraphy A secondary objective is to document the sedimentation processes/patterns associated with a large contemporary flood event on a medium-sized Asian river. Maximum sediment depths of 15 cm were found on the river levee, within 30 m of the main channel, and at 350 m thickness was 4 cm. Sediment depth generally decreased exponentially with distance away from the main channel. The extent of sediment deposition was about 1 km from the river channel. However, 72% of the sediment was deposited within an oval-shaped area 200–400 m from the main channel and centered on a tributary stream, through which sediment-laden water entered the floodplain, in addition to overtopping the levee of the main channel. Sediment concentration during the flood was estimated at 800–1500 mg L−1; and we believe the sediment was delivered by flows of well-mixed flood water occurring over a 1–2 day period. These data suggest that flood-deposited strata related to 30-year recurrence floods is only likely to be preserved in deposits located relatively close to the main river channel where fine sand and clayey coarse silt deposits have thicknesses of at least 5–10 cm. These relatively thick deposits would survive bioturbation, whereas more distal areas with thin clayey silt deposits would not.
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Scott, Daniel N., e Ellen E. Wohl. "Geomorphic regulation of floodplain soil organic carbon concentration in watersheds of the Rocky and Cascade Mountains, USA". Earth Surface Dynamics 6, n.º 4 (23 de novembro de 2018): 1101–14. http://dx.doi.org/10.5194/esurf-6-1101-2018.
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Abstract. Mountain rivers have the potential to retain OC-rich soil and store large quantities of organic carbon (OC) in floodplain soils. We characterize valley bottom morphology, floodplain soil, and vegetation in two disparate mountain river basins: the Middle Fork Snoqualmie in the Cascade Mountains and the Big Sandy in the Wind River Range of the Rocky Mountains. We use this dataset to examine variability in OC concentration between these basins as well as within them at multiple spatial scales. We find that although there are some differences between basins, much of the variability in OC concentration is due to local factors, such as soil moisture and valley bottom geometry. From this, we conclude that local factors likely play a dominant role in regulating OC concentration in valley bottoms and that interbasin differences in climate or vegetation characteristics may not translate directly into differences in OC storage. We also use an analysis of OC concentration and soil texture by depth to infer that OC is input to floodplain soils mainly by decaying vegetation, not overbank deposition of fine, OC-bearing sediment. Geomorphology and hydrology play strong roles in determining the spatial distribution of soil OC in mountain river corridors.
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Marion, G. M., K. Van Cleve e C. T. Dyrness. "Calcium carbonate precipitation–dissolution along a forest primary successional sequence on the Tanana River floodplain, interior Alaska". Canadian Journal of Forest Research 23, n.º 5 (1 de maio de 1993): 923–27. http://dx.doi.org/10.1139/x93-120.
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Calcareous (alkaline) soils exist along the river floodplains of interior Alaska. In calcareous soils, the balance of CaCO3 reflects net system acidification–alkalinization. The objectives of this study were to determine the origin of the CaCO3, quantify CaCO3 precipitation–dissolution, and quantify net system acidification–alkalinization along a forest primary successional sequence (250 years) on the Tanana River floodplain of interior Alaska. The CaCO3 concentrations in the initial soil profiles were positively correlated (R2 = 0.883) with silt concentrations. Differences in CaCO3 concentrations in the early soil profiles between sites of similar age, between forest successional stages, and among soil horizons within a profile are primarily due to differences in silt concentrations, which are controlled by the alluvial deposition process. There was a curvilinear decrease in CaCO3 content along the forest successional sequence, suggesting that the CaCO3 originated with the alluvial material and was not formed insitu. The loss of CaCO3 was equivalent to a loss of acid-neutralizing capacity of 10.0 kequiv•ha−1•year−1, which is a high rate of soil acidification. These forested, relatively pristine ecosystems are dominated by internal sources of acidity.