The Geotechnical Engineering Office visits a slope at the Hong Kong University of Science and Technology in Clear Water Bay. Photo: Felix Wong
Source:
https://scmp.com/news/hong-kong/health-environment/article/3004737/highest-number-landslides-decade-reported-hong Health & Environment
Highest number of landslides in a decade reported in Hong Kong last year – but don’t blame Typhoon Mangkhut says Geotechnical Engineering Office
- Recorded rainfall is deciding factor for landslides, says deputy head of office in charge of upkeep of Hong Kong’s slopes
- Urbanisation, slope degradation and extreme weather all led to increased risk as government to use HK$1 billion annually to prevent landslides
More than 250 landslides were reported in Hong Kong last year, the highest number for a decade. Photo: Felix Wong
More than 250 landslides were reported in Hong Kong last year, the highest number for a decade, the office responsible for the upkeep of slopes in the city has revealed.
Urbanisation, slope degradation and extreme weather had all led to an increased risk, according to Au Yeung Yan-sang, the deputy head of the Geotechnical Engineering Office.
“More buildings are being constructed near slopes, so the risk will increase,” Au Yeung said.
“We have carried out measures to prevent the risk of landslides.”
According to Au Yeung, HK$1 billion would be used each year as part of a government plan to prevent landslides.
Some 150 man-made slopes owned by the government would be consolidated each year, and safety screening would be conducted for 100 privately owned man-made slopes. Mitigation measures for 30 natural hillside catchments would also be carried out.
“The number of landslides since 2008 has been lower than the average of 300 over the past 25 years. Hong Kong hasn’t experienced a huge rainstorm since 2008,” Au Yeung said.
In 2008, 863 landslides were reported according to government statistics. The figure for 2018 was 253.
While Typhoon Mangkhut last year was a tropical cyclone of historic proportions, the number of landslides recorded in its wake was not even the highest in 2018, Au Yeung said.
Jenny Yeung, chief geotechnical engineer (left) and Au Yeung Yan-sang. Photo: Felix WongFelix Wong
Some 27 landslides were reported following the typhoon signal number 10 storm, the highest category on Hong Kong’s scale, which hit the city on September 16. The landslip warning signal was issued a day earlier and remained in place for 38 hours, according to statistic provided by the office.
However, 58 landslides were reported between August 29 and 30, when the landslip warning signal was up for 27 hours.
Under a government plan, 150 man-made slopes owned by the government would be consolidated each year, and safety screening would be conducted for 100 privately owned man-made slopes. Photo: Felix Wong
“During Typhoon Mangkhut, 162mm of rainfall was recorded in Tsuen Wan during the four heaviest hours,” Au Yeung said. “However on August 29 in Ta Shek Wu in Pat Heung, 314mm of rainfall was recorded over the peak four hours.
“The amount of rainfall recorded is the deciding factor for landslides.”
Jenny Yeung Fei, chief geotechnical engineer at the office, said: “If slopes aren’t properly maintained, they will deteriorate and landslides may occur, causing injuries to people and damage to property.
“If this happens, private slope owners may face greater expenses for remedial works and claims for damaged property.”