Old works 'safe' amid tunnelling

PUBLISHED : Monday, 11 February, 2008, 12:00am
UPDATED : Monday, 11 February, 2008, 12:00am

Officials have promised that tunnelling work needed to replace reservoirs near the University of Hong Kong as it expands its campus will not affect a grade-three-listed waterworks in the middle of the site.

Two saltwater reservoirs are being rebuilt underground to minimise the impact on the environment.

The 77-year-old Elliot Treatment Works has been protected with extra structures and wrapped in a protective screen while workers labour around the clock to drill a 70-metre-long cavern into hard granite and sandstone.

Officials said regular monitoring had found no signs of subsidence, cracks or displacement of the treatment works.

'We have made heavy structures to protect the building. No matter how the contractor digs the caverns, it will remain steady and will not collapse,' Chan Tze-ho, senior engineer of the Water Supplies Department, said.

Mr Chan said the cavern would be dug with machines only and no explosives would be used.

The treatment works, which is owned by the department, is being preserved along with two other historic structures on a site in Pok Fu Lam where the university will build its Centennial Campus.

The university is spending HK$800 million, one-third of the cost of the development, to preserve the buildings and replace the reservoirs.

The other two structures - a grade-two-listed staff quarters and a grade-three-listed workmen's quarters - have been turned into the contractor's offices.

The site, west of the main campus, used to be an underground drinking water and seawater reservoir serving 250,000 residents but had to be relocated to allow the campus extension.

A previous extension plan would have involved not just bulldozing the quarters but also cutting a huge area of greened slope to move the water storage underground.

But the university and department later agreed to change the plan by putting the seawater storage facility into a cavern dug into the hill.

As a result, the two heritage buildings could be preserved. Upon completion of the work, they will be handed to the university.

Water officials said it was the first time reservoirs had been built in underground caverns.

Liquid assets

The water utilities replacement work will be completed by next year

The cost, which is being funded entirely by the university, in HK dollars $530m