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

100%

Michalec B., Tarnawski M.

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

2008

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.

Recorded lag times of snowmelt events in a small catchment

100%

Hejduk A., Banasik K.

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

2011

tom 43

nr 1

The hydrological and meteorological data collected in small, lowland catchment during snowmelt floods have been used to calculate lag time of runoff (Lag) and lag time of sediment yield (Lags). Both, Lag and Lags are important characteristics of the instantaneous unit hydrograph (IUH) and instantaneous unit sedimentgraph (IUSG). Field data from Zagożdżonka River catchment have been used to demonstrate the relationship between lag times. The results of investigation show that: a) there is a strong relationship between Lag and Lags; b) in most cases the value of a= Lags/Lag is smaller than 1; c) in case of snowmelt floods there was only poor correlation between parameter a and the total runoff depth (water supply).

Ograniczanie wyników

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

1 Banasik K.

1 Hejduk A.

1 Michalec B.

1 Tarnawski M.

1 2011

1 2008

Wyniki wyszukiwania

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

Recorded lag times of snowmelt events in a small catchment