Artificial lakes and reservoirs serve as traps for suspended sediment. In this paper we study sediments in Brno dam and Nové Mlýny reservoirs. We determine the sedimentation rate and depth of dam sediments. 137Cs dating were used for determination of chronology. Magnetic susceptibility and X-ray densitometry were used to establish a stratigraphic framework in the cores. 137Cs dating revealed a distinct Chernobyl peak at 44–48 cm depth inferring an average sedimentation rate of 2.3 cm per year in the Nové Mlýny reservoir. In the Brno reservoir, the Chernobyl peak was located in 62–65 cm depth indicating an average sedimentation rate of 3.04 cm per year
