The assessment of sediment amount transported by river based on indirect methods may lead to considerable errors. It particularly pertains to the assessment of transported suspended sediment quantity. In the paper methods are presented of determining the amount of load transported by the river and supplied to the water reservoir at Krempna on the Wisłoka river. The quantity of load flowing into the reservoir determined on the basis of field measurements was assumed reliable in the assessment of applied computational methods. On the basis of results of the multi-annual investigations on the silting processes, the authors, set a value of β-parameter using the results of the silting volume measurements and load transport computations during the subsequent years of the reservoir’s operational period. The sediment trap efficiency of the reservoir determined on the basis of transported sediment mass computed according to bathometric measurements and silting surveys ranges between 65% in 1998 and 50% in 2005. The determined sediment trap efficiency on the basis of the results of calculations by the DRUSLE method is on about 30% larger than the sediment trap efficiency value calculated on the basis of bathometric measurements. The amount of sediment transport computed by the MUSLE method is much lower than the sediment mass trapped in the reservoir. Hence also the sediment trap efficiency appointed on the basis of the results of calculations by the MUSLE method is larger than 100%.