Determination and comparison of hydraulic conductivity values of bed silts along Chotárny channel using grain size analysis

Rok, strany: 2020, 139 - 144

This paper goes in for the evaluation of permeability of the bed silts located along the Chotárny channel at the Žitný ostrov (ŽO), Slovakia. The Chotárny channel is one of three main channels at the ŽO area – the flat lowland with channel network. Whole ŽO area has very low slope, so longitudinal slopes of all channels are negligible. This fact influences the formation of silts on the channel bottom. The bed silt permeability impacts water flow between surface water in the channel and surrounding groundwater in the scope of their interaction at this area. It is expressed by value of hydraulic conductivity, for our case, inasmuch as the bed silts are located in saturated zone under water level, by value of saturated hydraulic conductivity. This paper deals with disturbed samples extracted from the Chotárny channel and for that reason only the empirical formulas based on the grain size analysis were used for assessment of saturated hydraulic conductivity value. The disturbed samples were extracted in three different vertical parts of silt – top, middle and bottom part of silt layer and subsequently as mixed samples in each selected profile of the Chotárny channel. The selection of sampling place was made by thickness of bed silt in the measured profiles. The values of saturated hydraulic conductivity obtained from disturbed samples of bed silt – Kd were calculated according to three empirical formulas: 1. Bayer – Schweiger formula; 2. Špaček I formula and 3. Špaček II formula, firstly for samples from the single vertical parts of the silt layer (top, middle and bottom) and then for mixed samples. The valid values Kd from single parts of the silt layers reached from 1.29x10-08 to 1.19x10-04 m s-1, the valid values Kd from mixed samples reached from 1.38x10-08 to 4.11x10-06 m s-1. All values obtained using grain size analysis are only approximate, but the only possible ones in case of impossibility to take an undisturbed samples. According to results of comparison of Kd from single vertical parts of silt layers and Kd from mixed samples it is not possible to assess explicitly which values set of saturated hydraulic conductivity are more suitable to use in calculation or modelling. Next analysis of obtained datasets and comparison with the values of saturated hydraulic conductivity from undisturbed samples of bed silt will be necessary.

ISO 690:

Dulovičová, R., Velísková, Y., Schügerl, R. 2020. Determination and comparison of hydraulic conductivity values of bed silts along Chotárny channel using grain size analysis. In Acta Hydrologica Slovaca, vol. 21, no.2, pp. 139-144. 2644-4690. DOI: https://doi.org/10.31577/ahs-2020-0021.02.0017

APA:

Dulovičová, R., Velísková, Y., Schügerl, R. (2020). Determination and comparison of hydraulic conductivity values of bed silts along Chotárny channel using grain size analysis. Acta Hydrologica Slovaca, 21(2), 139-144. 2644-4690. DOI: https://doi.org/10.31577/ahs-2020-0021.02.0017

Vydavateľ: Institute of Hydrology SAS, Dúbravská cesta 9, 841 05 Bratislava, Slovakia