To support Hong Kong's sustainable development, the Government actively explores innovative approaches to develop new land resources. One possible approach is rock cavern development.
Cavern construction is an established technology that has seen continual improvement in its application. A number of cavern schemes for various uses have been successfully adopted around the world with notable examples in Canada, China, Finland, Japan, Korea, Norway, Singapore, Sweden and the USA.
In fact, there are successful local examples of accommodating facilities in rock caverns, including the Stanley Sewage Treatment Works completed in 1995, as well as Island West Refuse Transfer Station and Kau Shat Wan Explosives Depot both completed in 1997. Also, in 2009, the University of Hong Kong reprovisioned the Western Salt-water Service Reservoirs in rock caverns to release the site for its Centennial Campus development. These projects have demonstrated that rock caverns are valuable resources, while providing added environmental, safety and security benefits for many applications.
Civil Engineering and Development Department (CEDD) completed the study on "Enhanced Use of Underground Space in Hong Kong" in March 2011. It found that two-thirds of the total land area in Hong Kong was suitable for rock cavern development which can release the surface site currently occupied by existing government facilities. CEDD also completed the study on "Enhancing Land Supply Strategy - Reclamation outside Victoria Harbour and Rock Cavern Development" in 2014 and recommended to proceed a feasibility study on the relocation of the Sai Kung Sewage Treatment Works (SKSTW) to caverns. The relocation can release the existing site (about 2.2 hectares) for housing and other beneficial uses. The relocation site was preliminarily proposed at Tsiu Hang.
In order to provide adequate treatment capacity to cater for increase in sewage flows arising from committed and planned development at Sai Kung, DSD will consider to upgrade the treatment capacity of the SKSTW to 23,000 m3
per day under this caverns feasibility study.