Comprehensive disaster mitigation in watershed areas
A combination of check dams and submerged dams and engineering methods such as river regulation, embankments, water drainage, and vegetation and landscaping are used to deal with seriously scoured and silted wild creeks and gullies as well as collapsed sites and landslides. The choice of methods depends on local circumstances. The purpose is to deliver concrete benefits such as disaster prevention and soil and water resource conservation over a short period of time. In recent years, with rising public awareness of the importance of environmental protection and conservation, amenity embankments, landscaping, and ecological engineering methods are being incorporated into the treatment methodology.
Comprehensive treatment programs using watersheds as units were formulated for eastern and western Taiwan in 1980 and 1992, respectively. Up to the year 2000, a total of NT$12.7 billion was invested in eastern Taiwan and NT$24.1 billion in western Taiwan . In 2001, the two programs were merged and a budget of NT$3.0 billion was approved. A budget of NT$2.9, 2.8, and 2.6 billion was slated for 2002, 2003, and 2004, respectively. The programs were devised for the treatment of soil and water, landslides, environmental protection and conservation, and relevant experiments and research. The outcome has been widely recognized.
In the wake of Chichi Earthquake, which inflicted severe damage to seven counties and cities in central Taiwan , followed by Typhoons Xangsane, Toraji and Nari, which triggered serious debris flow disasters, many disaster areas have been in dire need of reconstruction and treatment. The government, in recent years, has been more active in raising funds for reconstruction and treatment, and the budgets so allocated have exceeded over 50% of the SWCB's annual budget.
Landslide treatment in Lishan
Uninterrupted torrential rains in the middle of April 1990 triggered new landslides in the old landslide zone of Lishan, Taichung County . Covering an area of 230 hectares, the landslides caused road interruption and destroyed buildings including the Lishan Hotel.
To prevent the disaster from escalating, the Industrial Technology Research Institute was commissioned to prepare the Program for Investigation and Treatment of Landslide in Lishan in 1991. Approved by the Executive Yuan in February 1995, a budget of NT$1.25 billion was allocated to the program, carried out from 1995 to 2002.
Up to 2002, a total of NT$1.07 billion was slated for appropriate treatments such as surface water drainage, drainage pipe ditches, water drainage channels, lateral drainage pipe ditches, check dams, submerged dams, riverbed stabilizing sills and monitoring system, which were completed in stages. Completion of the program has effectively stabilized slope surface and allowed smooth traffic flow.
Thanks to careful monitoring of the affected areas, the threat landslides pose has been effectively eased. There was no obvious movement in the affected area following the 1999 Chichi Earthquake and the downpour of torrential rain during reconstruction.
Establishment of a technical system for disaster prevention
In the wake of the Chichi Earthquake in 1999, the government has been striving to utilize new technologies and recruit experts and scholars in order to establish a technical system for the prevention of mountain disasters, to rapidly and effectively prevent debris flows, and to ensure the safety of lives and property.
Projects such as survey on potential debris flow torrents in Taiwan, survey on landslides, formulation of debris flow warning thresholds, establishment of debris flow monitoring demonstration stations, geographic information system on the Internet, debris flow disaster prevention and emergency operation system, development of project management and inspection system, exercises of debris flow disaster prevention, as well as planning and demonstration of evacuation routes were completed to raise public awareness of disaster prevention.
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