Characteristics and origin of suspended matter in a reservoir of the “small retention” category (Poland)

Abstract The study described involved qualitative and quantitative analysis of suspended sediment in a body of water, with origins also determined. The reservoir in question – in the so-called “small retention” category, is located in Blizne, Podkarpackie Voivodeship (SE Poland), and was studied during summer 2017. Results showed a linear negative correlation between the suspended sediment content in water and the latter's organic matter content. There was also a clear relationship between the suspended sediment content and the rate of sedimentation of solid particles suspended in the water column. The research showed that the TOC-to-OM conversion factor commonly applied to bottom sediments does not apply to sediments consisting of sedimentation particles in the water column. It was also observed that the organic matter prevailing in entrapped sediment was of autochthonous origin. The share of the latter was greatest, and the content of total phosphorus highest, in the collected sediments while water was being retained in the reservoir for the longest period. The increase in phosphorus content co-occurred with the lowest TOC: TN ratio, and with a decrease in the sedimentation rate as compared with other series. Analysis has thus shown that the composition and specific nature of suspended sediment in this reservoir affects the rate of deposition of matter and can determine the silting processes.