Abstract Over 80 years ago the scientists conceived and implemented a concept of energetic utilization of the Słupia River. The reservoirs have not been dredged and thus they remain exemplary sumps, sediment reservoirs of matter from the denudated reception basin. In Krzynia reservoir the last and Bytowski reservoir the first link of the cascade there is a great number of various granularity sediments. Thick sediments (sand, gravel and pebbles) cover narrow belts of a shore shallow of both reservoirs while fine sediment (slime and loam) is available in an open reservoir. A spatial distribution is an effect of depth differentiation; the deeper it gets the smaller diameter of granulation and the higher concentration of organic matter.

An average annual pace of accumulation is higher in Bytowski reservoir: 3,7 cm in a front belt of the delta and 1,4-1,5 cm in a limnetic zone. In Krzynia reservoir the proportions are: 2,5 cm in a front belt and 0,6-0,9 cm in a limnetic zone. The proportions are comparable to other reservoirs in Poland and neighboring countries. Concentration of the selected indicators (biogens, heavy metals and polynuclear aromatic hydrocarbons) do not exceed the level of geochemical background.

Keywords: Słupia River’s cascade, the river bottom sediments, biogens, heavy metals, barrier reservoir