The drift distance, offset distance, and landing range of sandbags thrown by bottom-opening barges and flipper boats in the presence of riverbank slopes are analyzed through generalized flume experiment. The influence of different throwing methods is also investigated. The experimental results show that the existence of the riverbank slope will cause the sandbags to slide or roll, increasing their drift and offset distance. Moreover, as the slope gradient increases, the landing points of the sandbags become more scattered in the downstream direction. The average drift distance of sandbags increases with the flow velocity. When the flow velocity is high, the variation in slope gradient has a relatively small impact on the drift distance of the sandbags. However, when the flow velocity is low, the average drift distance of the sandbags thrown by the bottom-opening barges increases with increasing slope gradient, while the landing points of the sandbags thrown by the flipper boats become more concentrated in the downstream direction. The throwing method of bottom-opening barges results in more dispersed landing points compared to flipper boats, although the difference in landing range between the two throwing methods is insignificant.