Civil Engineering and Development Department (Hong Kong SAR), China

Hong Kong Takes Slope Safety to New Heights

buildings The Challenge:

Hong Kong is one of the most densely populated places in the world. Approximately 6.8 million people live in an area just more than 1,000 square kilometers, giving Hong Kong a population density of 6,300 people per square kilometer. A substantial portion of the city’s dense urban developments are on steep hillsides. Extensive excavation into the existing hillsides, as well as the creation of fill slopes, have been necessary to provide platforms for building and infrastructure developments. Hong Kong has 57,000 of these man-made slopes, of which 17,000 are on private land, and are therefore the responsibility of private owners to maintain. Coupled with torrential summer rainfall and an average of 300-400 landslides per year, Hong Kong’s challenge in maintaining slope safety is unique, and is a shared responsibility of the Government and private land owners.

In the late 1990s, the Civil Engineering and Development Department (CEDD) embarked upon a $14 million (U.S.) project to identify, register, and collect information on all of Hong Kong’s sizeable man-made slopes. Data such as photographs, text, and graphical information was collected for 57,000 slopes. To improve public awareness of slope safety, and facilitate maintenance planning, CEDD needed to establish a slope information system on the Web and Government intranet. The Geotechnical Engineering Office of CEDD oversaw the development and management of this project.

The Objectives:

Provide a spatially enabled online slope information system for the Government and public
Establish a system that could handle 50 Gigabytes of slope information, using data in various GIS formats
Enable fast, real-time retrieval of information during landslide emergencies

The Solution:

With the assistance of Intergraph Hong Kong, CEDD published its Catalogue of Slopes to the World Wide Web and government intranet using GeoMedia WebMap. As CEDD’s Deputy Head of the Geotechnical Engineering Office (Island), Mr. S.H. Mak, explained, “We looked at a number of vendors in choosing software to publish spatial information to the Web. We chose GeoMedia WebMap because of its ability to read data in different formats, and its value-for-money spatial functionality.”

The Slope Information System provides real-time, comprehensive slope information to users through the government intranet and the Web at http://hkss.cedd.gov.hk. During landslide emergencies, maps are generated on the government intranet to show the location and seriousness of the landslides. This information assists the Emergency Controller to monitor the situation and assign emergency resources appropriately. The comprehensive slope information in the System is also useful to owners of private slopes on a day-to-day basis, to assist in planning maintenance and improving stability. The provision of free slope information on the Web enhances the government’s role in caring for the community, and making information delivery to the public highly transparent, up-to-date, and efficient.

The intranet site provides additional functionality to allow government users to run spatial query functions. For instance, staff who plan and design upgrades to slopes can extract relevant slope information using buffering techniques as well as length and area measurements, all in batch mode to save time.

Future Plans:

CEDD is continually improving the site to enhance the performance and functionality of the slope information system. The next stage is to migrate the system to publish slope information in open data formats such as XML and GML. CEDD is also interested in adding mobile functionality to the system. This would allow staff to use personal digital assistants (PDAs) for data retrieval and updates in the field.

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