The influence of wind, fetch, and water depth on the distribution of sediments in Lake Vänern, Sweden

Palaeolimnological studies rely on assumptions regarding the distribution and completeness of lake deposits that are not always fully supported by observations. In particular, the assumption that "focusing" of suspended sediments leads to preferential deposition in the deepest part of a lake is not always justified, especially in upland lakes subject to energetic wind forcing. Few studies have investigated the hydrodynamic controls on lake sediment focusing, especially the importance of wind-driven currents in deep water. We combine a three-dimensional numerical hydrodynamic and suspended sediment model (FVCOM) with a semi-empirical wind wave model to investigate the potential mobility of bottom sediments in a small oligotrophic upland lake (Llyn Conwy, north Wales, UK). Exploratory simulations of wave-and current-generated bottom stress and suspended sediment dynamics confirm the expected importance of wave-generated bottom stresses in shallower waters (< 3 m depth) around the shore. Field survey shows that lake sediments are largely absent from this zone. This is consistent with peripheral wave action as a sediment focusing mechanism. In deeper water, wind-driven currents become the dominant contributor to bottom stress. Strong wind forcing events drive an energetic circulation with peak bottom stresses that intermittently exceed any realistic erosion threshold over a large proportion of the lake at depths far below those at which waves can be effective. The spatial distribution of lake sediments, and the completeness of the sediment record, is thus determined by a complex interaction between wind-driven circulation and bathymetry, rather than by bathymetry alone. Although our sediment dynamics simulations are purely exploratory, the results are consisted with survey results that show a patchy distribution of deep-water accumulation. Some implications of these results for the selection of sediment coring locations and the interpretation of sediment records are considered.

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“…According to Håkanson (1977), sediment will not accumulate on slopes > 14%. Below 4%, slope has no effect.…”

Section: Evaluation Of Alternative Sediment Focusing Mechanismsmentioning

confidence: 99%

Three‐dimensional hydrodynamic and sediment transport modeling to test the sediment focusing hypothesis in upland lakes

Morales-Marín

French

Burningham

et al. 2017

Limnology & Oceanography

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“…Mobilized sediments are focused into, and re-deposited in the still submerged parts of the reservoir (Anderson et al, 1988). Hakanson (1977) divided lake bottoms into three zones: an erosional zone, characterized by coarse material and high water turbulence; a transportation zone of discontinuous sedimentation interrupted by infrequent periods of resuspension and removal of material; and an accumulation zone of fine sediment, where no reworking occurs, and sediment properties are replicable over the area. Sediments in both the erosional and transportation zone are thus unsuitable for core collection.…”

Section: Stage 1: Core Collectionmentioning

confidence: 99%

Establishing the sediment stratigraphy of reservoirs in the southern Pennines, UK

Shotbolt¹,

Hutchinson²,

Thomas³

2001

Hydrological Sciences Journal

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Reservoirs in the southern Pennines have been investigated to determine their potential for reconstructing a history of atmospheric pollution. A selection procedure has been used to identify sites with the best chance of obtaining a usable sedimentary record prior to sample collection. Five reservoirs were selected for core collection and sediment analysis using magnetic susceptibility (%i f ), particle size, spheroidal carbonaceous particle (SCP) analysis and radiometric dating. Analysis reveals that largely undisturbed sedimentary records exist in the deepest zones of these reservoirs, thus reservoir sediments represent a valuable resource for investigating pollution histories in the southern Pennines.Key words reservoirs; southern Pennines; sediment stratigraphy; particle size; magnetic susceptibility; spheroidal carbonaceous particles Etablissement de la stratigraphie sédimentaire de réservoirs des Pennines du Sud, Royaume UniRésumé Des réservoirs des Pennines du Sud ont été étudiés pour déterminer leur potentiel dans la reconstitution de l'histoire de la pollution atmosphérique. Une procédure de sélection a été utilisée pour identifier les sites qui présentent les meilleures chances d'obtenir un enregistrement sédimentaire utilisable, avant la prise d'échantillons. Cinq réservoirs ont été choisis pour recueillir des échantillons par carottage et analyser les sédiments du point de vue de la susceptibilité magnétique (Xif), de la taille des particules, des particules spéroïdes carbonées et de la datation radiométrique. L'analyse montre que des profils sédimentaires particulièrement bien conservés se trouvent dans les zones les plus profondes de ces réservoirs, constituant ainsi une ressource pertinente pour étudier l'histoire de la pollution dans les Pennines du Sud.

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“…Geometric conditions of lakes determine energy and matter exchanges on the external border surfaces and their transfer within the lake. Thus, morphometric features of lakes also affect heat balance (Gorham 1964;Lange 1986), stratification and mictic type (Patalas 1960;Lathrop and Lille 1980;Gorhan and Boyce 1989), sediment dynamics (Håkanson 1977a;Blais and Kalff 1995), water residence time and flushing rate (Pasławski 1975;Johnson et al 1978;Lerman and Hull 1987), distribution of nutrients and dissolved gases in a water column (Eberly 1964;Nuremberg 1995), light regime (Borowiak 2011), and consequently primary production (Fee 1979;Guildford et al 1994) and qualitative characteristics of lake water (Nõges 2009;Stefanidis and Papastergiadou 2012).…”

Section: Introductionmentioning

confidence: 99%

A new bathymetric survey of the Suwałki Landscape Park lakes

Borowiak

Nowiński

Grabowska

2016

Limnological Review

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Abstract:The results of the latest bathymetric survey of 21 lakes in the Suwałki Landscape Park (SLP) are presented here. Measurements of the underwater lake topography were carried out in the years 2012-2013 using the hydroacoustic method (sonar Lawrence 480M). In the case of four lakes (Błędne, Pogorzałek, Purwin, Wodziłki) this was the first time a bathymetric survey had been performed. Field material was used to prepare bathymetric maps, which were then used for calculating the basic size and shape parameters of the lake basins. The results of the studies are shown against the nearly 90 year history of bathymetric surveying of the SLP lakes. In the light of the current measurements, the total area of the SLP lakes is over 634 hm 2 and its limnic ratio is 10%. Lake water resources in the park were estimated at 143 037.1 dam 3 . This value corresponds to a retention index of 2257 mm. In addition, studies have shown that the previous morphometric data are not very accurate. The relative differences in the lake surface areas ranged from -14.1 to 9.1%, and in the case of volume -from -32.2 to 35.3%. The greatest differences in the volume, expressed in absolute values, were found in the largest SLP lakes: Hańcza

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The influence of wind, fetch, and water depth on the distribution of sediments in Lake Vänern, Sweden

Cited by 254 publications

References 17 publications

Three‐dimensional hydrodynamic and sediment transport modeling to test the sediment focusing hypothesis in upland lakes

Three‐dimensional hydrodynamic and sediment transport modeling to test the sediment focusing hypothesis in upland lakes

Establishing the sediment stratigraphy of reservoirs in the southern Pennines, UK

A new bathymetric survey of the Suwałki Landscape Park lakes

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