MORPHOLOGICAL CHANGE OF HOYENSHAN, MIAOLI COUNTY, TAIWAN.
Date Issued
2004
Date
2004
Author(s)
Cheng, Yeuan-Chang
DOI
zh-TW
Abstract
Hoyenshan, a gravel landscape classed as an area of badlands is located within the Miaoli Hills of Taiwan. The badlands area experiences severe erosion and accretion during extreme storm events. This study investigates the use of derived digital imagery (DDI), and digital terrain models (DTM) extracted using digital photogrammetry for quantifying the geomorphological processes that operate within Hoyenshan, for the years 1986, 1991, 1993, 1998 and 2002. DTMs of change enable volumetric calculations to be made for the upstream and alluvial fan areas between epochs. These demonstrate that the slopes experience parallel retreat and reduction in terrain elevation. During 1991 to 2002, the major changes observed are: (1) average parallel retreat of 2.5 metres associated with a slope elevation reduction of 1.5 metres. Sample profiles over a ten years period show that erosion and deposition occur in upstream areas, and during storm events, accumulated material is transported downstream with insignificant changes to the slope profile of the midstream areas; (2) an increase in erosion within all 1st order catchments; (3) No.3 drainage has the fastest rate of the uncovered area increasing about average 3 meters a year. Within Hoyenshan, drainage basin No.3 is the most dynamic, exhibiting the largest volume of debris accumulation which appears to have had an impact on the development of adjacent alluvial fans. This may be attributed to the large catchment area of drainage basin No.3, which during storm conditions produce large discharges that increase the opportunity for greater movement of eroded material. Analysis of the 1986 to 2002 data demonstrate that the typhoon event of 2001 is responsible for the significantly large volumes of material movement within the drainage basins.
Subjects
航空攝影測量
苗栗火炎山
侵蝕與堆積
邊坡後退
debris accumulation and erosion.
digital photogrammetry
Hoyenshan
alope retreat
Type
thesis
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