When you start walking around Hong Kong, you might notice that every retaining wall and slope has a sign on it, listing a registration number:
To me it seemed really odd: why would anyone care about a slope?
The reason is the environment that is Hong Kong: dense urban development on steep hillsides and torrential summer rainfall. Put the two other and you get landslips: in the 50 years from the end of World War II, they caused more than 470 people deaths.
To reduce the risk in 1977 the government established an entire government department to stabilise slopes: the Geotechnical Engineering Office.
The signs date from a four year project started in 1998 to catalogue all man-made slopes and retaining walls in Hong Kong, the final number was 60,000! Despite this, during my travels I still saw many examples of repair work being carried out to slopes:
The side effect of the slope improvements is that the majority of urban hillsides are covered in concrete, with drainage channels running along them to take away water, and access walkways part way up.
The entire western side of Tsing Yi island has been cut away to make room for a freeway, as seen from the Tsing Ma bridge.
You can see the registration sign on this slope:
With stairways leading upwards, allowi9ng for maintenance work to be carried out on the slope:
The monkeys are a story for another time…
- Review of recent building and civil works that involved large‐scale slope or rock cuttings – a presentation by Raymond Wong, City University of Hong Kong, to the Geotechnical Division, Hong Kong Institution of Engineers.
- Site formation and slopeworks – a presentation on the methods of slope protection, again by Raymond Wong.
- Application of GIS technology on slope registration for the prevention of landslide – journal article by Woo Chi Pong of the HK Civil Engineering and Development Department (CEDD).