Debris flow hazard posts a big threat to the main downstream of Jinsha River where a number of huge power stations are under
construction. The characteristics of spatial distribution of debris flows and the effect of their sediment yield on the reservoir
areas have been studied. An automatic recognition module was developed to extract the geometry of debris flow channels from
remote sensing data. Spatial distribution pattern of debris flows is obtained through combining the inventory database and
multi-source remote sensing investigation. The distribution of debris flows has high dependency on the various factors including
geology, geomorphology, climate, hydrology and human economic activities. The debris flows distributed in the study area are
characterized by group and pair distribution, uncompleted deposition fans, highly controlled by faults and tectonic activities,
spatial variation between left bank and right bank, and different subdivisions. The sediment yield caused by debris flow activates
is evaluated using multi-year observation data from numerous observation stations. Quantitative studies have been performed
on the relationship between the sediment yield and the debris flow area. A relatively fix ratio of 2.6 (×104 t/km2) has been found in different subdivisions of main downstream area which shows that the source of sediment discharged into
Jinsha River primarily come from debris flow activities. Another ratio is evaluated to represent the transforming possibility
of debris flow materials to bed-sediment load and suspended-sediment load in the river. Based on these findings, the potential
effect of sediment yield caused by debris flows on reservoir areas is discussed. The zonation map shows the different effect
of debris flow sediment on different dam site area which shows a good agreement with variation of debris flow spatial distribution. 相似文献
The Sichuan-Tibet railway goes across the Upper Jinsha River, along which a large number of large historical landslides have occurred and dammed the river. Therefore, it is of great significance to investigate large potential landslides along the Jinsha River. In this paper, we inspect the deformation characteristics of a rapid landsliding area along the Jinsha River by using multi-temporal remote sensing, and analyzed its future development and risk to the Sichuan-Tibet railway. Surface deformations and damage features between January 2016 and October 2020 were obtained using multi-temporal InSAR and multi-temporal correlations of optical images, respectively. Deformation and failure signs obtained from the field investigation were highly consistent. Results showed that cumulative deformation of the landsliding area is more than 50 cm, and the landsliding area is undergoing an accelerated deformation stage. The external rainfall condition, water level, and water flow rate are important factors controlling the deformation. The increase of rainfall, the rise of water level, and faster flow rate will accelerate the deformation of slope. The geological conditions of the slope itself affect the deformation of landslide. Due to the enrichment of gently dipping gneiss and groundwater, the slope is more likely to slide along the slope. The Jinsha River continuously scours the concave bank of the slope, causing local collapses and forming local free surfaces. Numerical simulation results show that once the landsliding area fails, the landslide body may form a 4-km-long dammed lake, and the water level could rise about 200 m; the historic data shows that landslide dam may burst in 2–8 days after sliding. Therefore, strategies of landslide hazard mitigation in the study area should be particularly made for the coming rainy seasons to mitigate risks from the landsliding area.
Debris flows occurring on Klapperhorn Mountain in the Yellowhead Pass in the Canadian Rocky Mountains pose a significant hazard to railway operations at the base of the mountain. The size (volume) and travel distance of these debris flows play an important role in assessing the risk to the railway. GIS analysis, airphoto interpretation together with field work were undertaken on two debris flows located at track mileage 54.0 and 54.3. Characteristics of these two debris flow events were analyzed, including debris flow path morphology and event behavior. Their sizes and travel distances were estimated using an empirical-statistical model (UBCDFLOW) under different initiation conditions. Their potential impact on the railway bridge was evaluated using a bridge blockage ratio. 相似文献