Issue 2007 No.1 - September 2007
Innovative Technology for the Re-provision of Reservoirs for the Development

The fresh and salt water reservoirs on the proposed site for the campus extension have served nearby areas for decades. At present, salt water is stored in two concrete surface reservoirs and fresh water in one underground reservoir. An opportunity to upgrade and re-provide these facilities arises as a result of campus development.

The University has adopted sustainability as one of the guiding principles for its Centennial Campus Development. This principle is the basis for formulating the preliminary design scheme to upgrade the salt water service reservoirs, by ensuring the environmental acceptability of the scheme not only during the construction stage, but also extending to the functional operation as well as to the realization of The University's vision of the future campus as a green oasis in the Western District.

Recognizing that the Site has significant environmental value being located adjacent to a Country Park, the HKU project team, working in close collaboration with experts and consultants, has determined that the conventional approach in building the new surface reservoirs would require significant slope cutting and the loss of tree cover, which is both environmentally and aesthetically unacceptable. Therefore, a new approach has been adopted, and under the principle of giving priority to being environmentally responsible, it is determined that the best solution is to relocate the salt water reservoirs in a cavern structure within the hillside so as to minimize the environmental and visual impact to the existing natural environment. This solution will result in minimum disturbance to existing vegetation and ecology.

The technology involved in the re-provision of salt water reservoirs has been proven promising in many parts of the world, however, it is the first of its kind for water storage application in Hong Kong.

The rock cavern will comprise of two salt water storage reservoirs connecting to a common section from an access portal. The single portal for the cavern is visually inconspicuous and minimize cutting into the natural hill-slope. Conforming to the environmentally sensitive principle, the cavern will be excavated using a non-explosive drill-and-break tunnelling method.

The rock cavern with the two salt water service reservoirs will be handed over to and operated by Water Services Department upon completion.
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