Influence of agricultural anthropopression on water quality of the dam reservoirs

Abstract

The quality of water in dam reservoirs is to a large extent dependant on human activity in the adjacent area. The research focused on the chemical composition of the water bodies in the agricultural catchments: Kozlowa Gora, Przeczyce and Laka (all located in the Upper Silesian Region Southern Poland). It was established that the reservoirs were often fed with flowing waters exhibiting eutrophication characteristics, especially with reference to nitrates content (average annual concentration − 3 NO > 10 mg/dm ). The fact should be associated with agricultural activity including fertilization management in the area covering at least 50% of the catchment. The eutrophication process was also observed in dam reservoirs. It might have been inferred from algae blooms. Besides, a strongly alkaline range of pH value was recorded in the water bodies. The highest water fertility was exhibited by the reservoir Laka, which may be associated with the fact that it is the area with the highest proportion of agricultural activities. It was additionally reflected by a high concentration of phosphates, on average about 0.389 mg/dm − 4 PO . The research revealed that the agricultural anthropopression threatens water reservoirs because of eutrophication and the subsequent deterioration of the quality of water resources.