Assessment of surface waters quality of small water reservoirs in agricultural landscape

In the article are presented results from water quality monitoring of six small water reservoirs situated in agricultural landscape in different Slovak regions. The study period was from June 2020 to September 2021. Studied parameters covered oxygen regime, total dissolved solids, fluorescent dissolved organic matter, turbidity, chlorophyll a, phycocyanin and phycoerythrin. All parameters were measured directly in the field using EXO YSI 2 probe. For interpretation of the measured data the application of different statistical approaches were used. The cluster analysis divided the six monitored water reservoirs in to two clusters. The Kruskal-Wallis test confirmed the significant differences between groups of water reservoirs. Analysis of normalized data revealed main parameters that caused the distribution in to two clusters: chlorophyll a, cyanobacterial photosynthetic pigments phycocyanin and phycoerythrin, turbidity and pH. In the cluster 2 the concentration ranges for these parameters showed large fluctuations. Comparison of the land cover structure of 500 m buffer zones pointed out the importance of buffer zone composition for better water quality. For the cluster 2 the highest proportion belonged to arable soils (63.63–92.00%) and only 1.12–9.33% to forests.