Hong Kong has about 60,000 registered man-made slopes of varying levels of strength, the result of rapid urban development near the city's hillsides in the 1960s and 1970s.
The identification of potential landslide risks, the upgrade and maintenance of natural slopes, and public education fall on the shoulders of the Geotechnical Engineering Office (GEO) of the Civil Engineering and Development Department (CEDD).
Several massive fatal landslides prompted the government to establish GEO in 1977 to reduce landslide risks caused by slope degradation in hillside developments, according to Terence Lam, senior geotechnical engineer at GEO.
Shortly after its establishment, the office developed and implemented the Slope Safety System and launched the Landslip Preventive Measures (LPM) programme which was completed last year.
"The LPM programme involved the systematic selection and study of all government slopes, followed by the maintenance and upgrading of substandard ones. Squatters' structures on dangerous slopes were cleared to minimise possible landslide damage to residents," Lam says.
Thanks to the LPM programme, about 7,000 high-risk man-made slopes were upgraded to meet safety standards.
"The overall landslide risk from man-made slopes has been reduced to less than 25 per cent of that in 1977," Lam says.
Following the LPM programme, GEO embarked on a Landslip Prevention and Mitigation programme (LPMitP) in 2008.
It has continued to identify and upgrade potentially problematic slopes among 15,000 slopes of moderate risk.
Through interpretation of large-scale historical aerial photographs taken in various periods, GEO has identified about 2,700 natural hillside catchments with known history of failure and close to existing buildings and roads.
On an annual and rolling basis, GEO aims to upgrade 150 government man-made slopes, conduct safety-screening studies for 100 private slopes, and carry out studies and necessary risk mitigation works for 30 natural hillside catchments through such measures as debris traps and barriers, Lam says.
The GEO recruits some 10 geotechnical engineers annually for two streams: geotechnical and geologist. Geological work includes extensive surveys to identify fault zones and build understanding of the different compositions of types of soils and rocks in various districts.
"The basic requirements for candidates in the geotechnical stream include corporate membership of the Hong Kong Institution of Engineers [civil or geotechnical discipline] elected after December 5, 1975 or equivalent and two years' experience in geotechnical engineering," Lam says.
"Or they should have a Hong Kong university degree in civil engineering, engineering geology or geology and four years of post-graduate experience in geotechnical engineering. Candidates for the geological stream are also required to have a degree in relevant disciplines and four years of post-graduate experience.
"As the office frequently deals with the public and attends meetings with district councils, the geotechnical engineers should have excellent communication and high emotional quotient on top of the technical competencies."
New recruits are appointed on permanent civil servant terms with a three-year probation.
Entry-level salary is at the master pay scale point 32 of HK$46,490. Depending on individual performance, a geotechnical engineer can be promoted to chief geotechnical engineer for each division.
One of GEO's major functions is to audit the design of geotechnical works to ensure they meet safety standards.
The auditing scope covers all building developments and civil engineering works and the standards of site supervision.
"A landslip warning system alerts the public to potential landslide danger. GEO operates a 24-hour emergency service to provide geotechnical advice to government departments on steps to be taken after a landslide," Lam says.