Summary:

The many years' measurements of silting the small water reservoir, closing the cachment covered loesses soils, allowed on the change qualification of the silt-ing degree during operation. In this work was compared the archival data from the measurements of silting the water reservoir in Zesławice, executed in the pe-riod before his desilting, with the results of measurements executed after desilting and building the side assistant reservoir. Water reservoirs in Zesławice are characterize the high intensity of silting. The Annual mean of silting ratio of res-ervoirs carries out: 3,0 % – the main reservoir before desilting, 1,87 % – the main reservoir after desilting and 1,00 % – the side assistant reservoir. Disposing the volume of sediment stopped in reservoirs the coefficient of the mechanical denudation was counted, definite by Wiśniewski as the relation of the volume of sediment deposited in the reservoir to the catchment area. The defi-nite approximate value of the denudation, for the help of this coefficient, proved considerably diverse in the individual years in which the measurements of silting were made. The mechanical denudation coefficient was counted for periods before and after desilting of the main reservoir. The results of the calculations of the transportation of suspended sediment, definite on the basis of bathometric meas-urements establish the basic research material, on the basis which the unitary de-nudation was qualified. Affirm, that the value of the mechanical denudation coef-ficient, the not taking into account quantity of suspended sediment flowing out from the reservoir, is about three the times lower than the unitary denudation, carrying out 91,7 t *km^-2 *rok^-1. Unitary denudation from the Dłubnia catchment definite on the basis of the seventeen - year - old sequence of the hydrological data is above twice smaller than the unitary denudation definite on the basis of calcula-tions methods Reniger-Dębski and Brański.