Rill erosion is studied in south-east and south western Taiwan respectively. Two types of mudrock sites were selected as they are made up of different types of mudrocks reflecting different sedimentary depositions and tectonic activities. The sites were instrumented to collect data that will be used to address selected issues related to slope retreat under a highly complex geomorphic environment, for the purposes of soil and water conservation. The methodology consists of a detailed field survey, continuous recording of site meteorological parameters, semi-automatic monitoring of the process and response parameters relevant to slope retreat, collection of photographic evidence, and laboratory analysis on the slope forming materials. The preliminary results obtained suggest that there is significant difference in rill development between the two sites. It is suggested that this is primarily due to the composition of the mudrock, the environmental conditions under which weathering occurs and the different processes of erosion. The development of gullies and rills in south-western Taiwan occur randomly and are dendritic in pattern. The Lichi area of south-eastern Taiwan demonstrates regular pattern of gully and rill development due in part to the degree of tectonic compression.