Streszczenie:

In this study, it was aimed at determining the seasonal variability in the sed-iment concentrations observed in an agricultural drainage basin. This research was carried out in an agricultural basin of 9 495 ha, located in the Cukurova region within the borders of Adana province, in Turkey. In order to determine the sedi-ment concentrations, an automatic water sampler was set at the outlet (L4) of the main drainage channel (YD2) that provides drainage of the basin. Drainage water samples with 250 ml volume were taken on a daily time step. Sediment concentra-tion values of the water samples taken were determined in the laboratory by the drying and evaporation method. The sediment concentration series observed in the 2020 hydrological year were directly associated with the sediment data observed simultaneously at the drainage flow observation station located in the Sirkenli village, downstream of the YD2. Daily sediment concentration series in L4 was disaggregated by months and seasons of the hydrologic year 2020 to make a tem-poral comparison among the data. Temporal analysis showed that the sediment concentration values have been prone to an increase in heavily rainy periods as well as in irrigation season. Additionally, it was determined that the correlation between sediment concentration values and drainage water depths in the main drainage channel was statistically insignificant during the peak irrigation season. The insignificant correlation between sediment concentration and drainage water depth might be ascribed to the direct by-pass irrigation flows to the drainage sys-tem of the agricultural basin.