Monitoring Techniques for Sediment Disaster in Mountant Area

In Taiwan, disaster prevention work has become an important issue for government agency which works for mountain area conservation, especially when disaster has become a complex kind of slope disaster combining landslide, debris flow, and flooding. In order to increase the ability of these complex disaster monitoring prewarning system in Taiwan area, one is to gain the prewarning time in which we can put much power-saving monitoring system more upstream, and the other way is to make the monitoring site much densely covered with disaster prevention class order low cost detecting instruments apply by low-frequency radio transmitter and mesh transfer technique for accurate data transmit. Another use of watershed prewarning technique is the UAV image providing different time of slope and riverbed landscape and also provides high-resolution DTM and DSM in order to calculate and provide numerical modification resources for different construction suggestions and monitoring sensor position replacement. In result, we use Han-Shi watershed in Yi-Lan County in northwest of Taiwan, and Li-Yi in Pin-Tung County in southern Taiwan has accomplished this goal and makes effort by the use of 158, 433 and 900 MHz all three different frequencies of radio transmission, and successfully transmit including five major collecting site, and 19 different signals for upstream debris flow of potential river monitoring for slope sliding amount, ground movements, ground moisture, rain amount, water level, and also site visions. From measurement result, we can assure that sediment transportation in this watershed can be measured in all three directions, and for protection site, large mass of sediment movement occurrence can be measured by these low-cost direct instruments and by the use of low-frequency radio network, prewarning alert can be proposed and old estimations for rainfall induced amount can be fixed more correctly.