Abstract

The purpose of this study is to establish a method of hazard assessment for the river terraces along the Chenyulan River and use 40 of them as protected objects. Using a geographic information system, the researchers extracted nine parameters for such terraces. These are length to attack shore, distance away from fault, distance from river channel, number of creeks and streams with possibility of debris flows, height above stream level, average slope degree, geology, number of erosion ditches, and distance from landslide area behind. Next, the weightings identified by analytic hierarchy process analysis were used as the basis for grading the various factors affecting river terraces. Hazard assessment for the river terraces then proceeded via totaling of the potential trends of the various factors and the protected objects, as well as comparison of historical disaster conditions and satellite images. The results showed that there were 8 high-risk river terraces, 14 medium–high-risk river terraces, 14 medium–low-risk river terraces and 4 low-risk river terraces. The evaluation of the current conditions of the settlement environment through parameter weighting has a certain accuracy and reference value in reducing the disaster impact of the riverine terrace settlement.

Highlights

  • Taiwan is located at the junction of the Eurasian continental plate and the PhilippineSea plate

  • The existence of river terraces indicates frequent geological changes, high erosion rates, abundant sources of silt, and strong river scour [1], but their formation is affected to some extent by climate change and human activities [2]

  • During the rainy season, the region is prone to typhoons, each of which tends to increase the intensity of rainfall within a short period of time, and this can result in landslides and mudslides in mountainous areas, as well as rapid rises in the water levels in rivers, which often results in flooding and the erosion and collapse of riverbanks

Read more

Summary

Introduction

Taiwan is located at the junction of the Eurasian continental plate and the PhilippineSea plate. Due to population growth and rapid industrial and commercial development in Taiwan in recent years, the use of flat land has become saturated, and development of hillside areas, especially river terraces, has become common. As Taiwan is surrounded by the sea on all sides, it receives abundant rainfall throughout the year, about 2500 mm, more than two and a half times the world annual average of 970 mm. During the rainy season (from 1 May to 30 November each year), the region is prone to typhoons, each of which tends to increase the intensity of rainfall within a short period of time, and this can result in landslides and mudslides in mountainous areas, as well as rapid rises in the water levels in rivers, which often results in flooding and the erosion and collapse of riverbanks. Due to the collapse of Xiandu (Xianto) Mountain, Xiaolin Village was destroyed, and a short-term barrier lake that was formed endangered the lives and property of residents downstream

Objectives
Methods
Conclusion

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.