Two series of artificial landslide dams were constructed on November 7th 2012 in the adjusted discharge experimental station, in Landao Creek, Huisun forest, Taiwan. We performed a dammed-lake failure experiment based on hydrological analysis and high precise observation using cameras and water level gauges. The experiment results suggest that the water level raising rate of the dammed-lake depend on the impoundment type and piping development; however, the water level decreasing rate depends on the type of dam breaching. The two serial dams experiment shows the breaching discharge from the upstream dam quickly induced overtopping failure that rapidly raised the water level of downstream dam and decreased the influence of piping.