Narisa Saejeng. Application of geographic information system for risk area of land subsidence in Nakhonpathom province . Master's Degree(Information Management on Environments and Resources). Mahidol University. : Mahidol University, 2007.
Application of geographic information system for risk area of land subsidence in Nakhonpathom province
Abstract:
The objective of this research was to analyze risk areas of land subsidence.
Risk factors were selected from related research on the problem of land subsidence.
There were six factors selected: geology, hydrogeology, wells, amount of groundwater
used, land use and population. The factors were analyzed by weighting and rating
scores from twelve governmental officers from concerned agencies. The total score of
each factor was employed to assess risk area of land subsidence by GIS and overlay
technique. The output in this study is a map of risk area of land subsidence in
Nakhonpathom Province.
In this study, the risk area of land subsidence was classified into three levels.
Most of the land consisted of areas at a moderate risk of subsidence and these areas
were scattered throughout the study area, covering 1,905.93 km2, while a high level to
at risk areas was found in parts of the west and south of the study area, covering
251.02 km2. The low level of land subsidence risk covered the least area, at only 14
km2, mainly in the northwestern and eastern parts of the study area. Furthermore, the
results showed land subsidence is most heavily influenced by excessive utilization of
groundwater. The second most influential factor is the number of wells.
A comparison of bench marks from the Royal Thai Survey Department,
ground checks of the real situation and the assessments made in this study showed all
three sources were in the same direction.