Variability of horizontal hydraulic conductivity of fen peats from Eastern Poland in relation to function of peatlands as a natural geological barriers

This paper presents the test results of horizontal hydraulic conductivity (k) of fen peats from eastern Poland. Three fen peatlands in the Lubartów Plateau (3 objects marked as LP1, LP2 and LP3) and two in the Siedlce Plateau (2 objects marked as SP1 and SP2) have been selected. Studied objects represent valley bogs type and are similar in peat thickness, but different in the occupied area. They are also vary in terms of botanic compositions and basic physical and chemical parameters of peats. The BAT permeameter was used to in-situ measurements of horizontal hydraulic conductivity. Horizontal hydraulic conductivity of studied peats varies from 1.3×10-8 m/s to 1.1×10-6 m/s. The lowest values of horizontal hydraulic conductivity were observed for silted (high-ash) carbonate peats and amorphous or pseudo-fibrous peats, while the highest values were observed for unsilted (low-ash) non-carbonate peats of fibrous structure. The analysis of variability of horizontal hydraulic conductivity showed that in each case the lowest values were observed for the bottom of the studied profile. The study allowed to indicate the specific areas within the peatlands differing in permeability and identify the role of individual objects as natural geological barriers.