Moisture Changes and ineffective rainfall on Masado Slopes During Rainfall

To predict slope failures induced by rainfall infiltration and groundwater flow it is very important to know behaviors of rainfall infiltration on actual slopes. Authors introduced in another paper about field monitoring system to measure moisture changes and groundwater level which is being carried out on natural Masado slopes near by a debris flow site which occurred on June 29, 1999. In this paper, behaviors of moisture changes during rainfall under consideration of different ground structure will be discussed. Then, in-situ water retention curve and unsaturated coefficient of permeability of Masado which observed from the monitoring results will be discussed. Then, ineffective rainfall, amount of rainfall which supplied to unsaturated layer before groundwater is generated at bottom layer, will be explained which leads to a very important conclusion about the mechanism of the formation water level in highly permeable materials like Masado