Morphological Change of Gravel Slope.-An Application of a Terrestrial Laser Scanner.
Date Issued
2012
Date
2012
Author(s)
Chang, Tsu-Ta
Abstract
In this study, we monitored 7 gravel slopes in 3 different research areas by terrestrial laser scanner (TLS). The purposes of this study are to assessment the feasibility of monitoring the mass movement on gravel slope by using terrestrial laser scan technique, and to detection of mass movement events by compare two different time measurement data of the hillslopes, then analysis the spatial pattern of the events on the hillslopes. And compare the spatial pattern of the events with gradient and topography, which are the two of the most important factor to the erosivity of overland flow.
Some mass movement events not occur on the hillslope with relative highly gradient, instead on the gentler gradient area, due to three possible resent. First, overland flow generate more impact as it flow through the boundary of the steep slope at upslope and the gentle slope at downslope. Second, the erosion force of overland flow is increase with the water depth increasing. Therefore, causing more mass movement events on gentle gradient hillslopes, because of the depth of overland flow on gentle gradient hillslopes is thicker than on steep slope. And third, the impact of rain splash on gentle gradient hillslopes is greater than on steep slopes.
The vertical linear patterns of mass movement events are appear on the all monitor slope in this study. The linear patterns are almost matching the rill on the hillslopes. It is indicating that the convergence topography gathers the overland flow on the hillslopes, and highly erosion force causing more mass movement events occur around the rill.
There is highly relationship between the spatial distribution of the erosivity of overland flow and the spatial pattern of the mass movement events on gravel hillslopes. Therefore, we can regard the spatial pattern of the events as an important information for the research of the overland flow on gravel slope in the future.
Some mass movement events not occur on the hillslope with relative highly gradient, instead on the gentler gradient area, due to three possible resent. First, overland flow generate more impact as it flow through the boundary of the steep slope at upslope and the gentle slope at downslope. Second, the erosion force of overland flow is increase with the water depth increasing. Therefore, causing more mass movement events on gentle gradient hillslopes, because of the depth of overland flow on gentle gradient hillslopes is thicker than on steep slope. And third, the impact of rain splash on gentle gradient hillslopes is greater than on steep slopes.
The vertical linear patterns of mass movement events are appear on the all monitor slope in this study. The linear patterns are almost matching the rill on the hillslopes. It is indicating that the convergence topography gathers the overland flow on the hillslopes, and highly erosion force causing more mass movement events occur around the rill.
There is highly relationship between the spatial distribution of the erosivity of overland flow and the spatial pattern of the mass movement events on gravel hillslopes. Therefore, we can regard the spatial pattern of the events as an important information for the research of the overland flow on gravel slope in the future.
Subjects
Gravel Slopes
TLS
Rock Fall
Debris Fall
Overland Flow
Type
thesis
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