Wyniki wyszukiwania

1

Critical velocities for non-cohesive grounds

100%

Zelazo J.

Annals of Warsaw Agricultural University. Land Reclamation

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1987

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tom 23

2

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Sediment segregation on weirs of lowland rivers

86%

Bajkowski S.

Annals of Warsaw University of Life Sciences - SGGW. Land Reclamation

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2010

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tom 42

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nr 1

177-185

Erosion and accumulation processes in the vicinity of water structures develop depending on the life of the facility, hydrological regime and morphology of the riverbed. Diversification of fl ow characteristics affects the segregation of bed sediment on section of period of weirs. Knowledge of factors determining granulometric diversity of bottom material allows for more appropriate bed and riverbanks protections design. It also enables estimation of the conditions of sediment transport down the watercourse and its participation in the balance of the transport of bottom material in the watercourse. Areas where sediment accumulates on the water structures are up water and down water positions, stilling basin and other cavities of the structure. The article presents an analysis of granulometric composition of bottom material in selected lowland weirs. Research facilities are weirs located on lowland rivers. Segregation of sediment material was observed on weir sections. Thickest sediment is piled in up water, smallest in down water.

3

Determination of conditions of suspended sediment transport in river and water reservoir

72%

Michalec B., Tarnawski M.

Annals of Warsaw University of Life Sciences - SGGW. Land Reclamation

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2008

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tom 39

The carried out measurement of waters flow and suspended sediment concentration in the river Wisłoka and the small water reservoir at Krempna constituted the basis of determination of conditions of suspended load transport at low water flow according to van Rijn’s criteria (1984). The results of measurements carried out in the river and in the reservoir permitted elaboration of profi les of suspended sediment concentration Ca on the reference level “a”. The reference level was established according to van Rijn’s methods. In the river the reference level was adopted as 0.5 of the diameter of the biggest particle, and in the water reservoir 0.01 of elevation in a given hydrometric vertical. Measurement were performed at a flow equalling 0.89 m3⋅s–1. Concentration Ca in the river in fi ve hydrometric verticals, determined from the concentration profile, ranged from 11.4 to 25.3 g⋅m–3. The concentration value, calculated according to van Rijn’s formula was within the range 11.2–36.5 g⋅m–3 and the average it was over 26% higher than that determined from the concentration profile. In the water reservoir concentration measurements were performed in appointed verticals in eight cross-sections. At a flow 0.89 m3⋅s–1 in the water reservoir critical bed shear velocities causing movement of bottom material will not be exceeded. The calculated stage transport parameter (T) equaled from –0.9961 to –0.9996 in particular verticals of cross-sections. With regard to the negative values of the stage transport parameter (T) it proved impossible to calculate concentration Ca in the reservoir by use of the van Rijn’s formula.

4

Dynamics of erosion process in the Warta River bed downstream of the Jeziorsko reservoir

58%

Przedwojski B., Wicher-Dysarz J., Wierzbicki M., Dysarz T.

Roczniki Akademii Rolniczej w Poznaniu. Melioracje i Inżynieria Środowiska

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2005

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tom 26

325-338

Ograniczanie wyników

2 Annals of Warsaw University of Life Sciences - SGGW. Land Reclamation

1 Annals of Warsaw Agricultural University. Land Reclamation

1 Roczniki Akademii Rolniczej w Poznaniu. Melioracje i Inżynieria Środowiska

1 Bajkowski S.

1 Dysarz T.

1 Michalec B.

1 Przedwojski B.

1 Tarnawski M.

1 Wicher-Dysarz J.

1 Wierzbicki M.

1 Zelazo J.

1 2010

1 2008

1 2005

1 1987

Critical velocities for non-cohesive grounds

Sediment segregation on weirs of lowland rivers

Determination of conditions of suspended sediment transport in river and water reservoir

Dynamics of erosion process in the Warta River bed downstream of the Jeziorsko reservoir