ABSTRACT
The Inter-Reservoirs Transfer Scheme (IRTS) in Hong Kong is undertaken by Drainage Services Department (DSD) to mitigate flood risks and conserve water. Bouygues Travaux Publics (BTP) constructed a 2.8km, 3m diameter water tunnel linking Kowloon Byewash Reservoir (KBR) to Lower Shing Mun Reservoir (LSMR) using the Tunnel Boring Machine (TBM) method. This project optimized drainage capacity and reduced the need for extensive urban pipe upgrades. Traversing beneath Kam Shan Country Park, the project addressed geological challenges such as high permeability and fault intersections. The topography rises steeply resulting in 200 m high groundwater table and ground cover. To consider the hillside groundwater regime, the tunnel was designed as undrained to resist full water pressure and to minimize environmental impact. Despite significant hurdles, including COVID-19 disruptions and managing variable geological conditions, innovative technologies and meticulous planning ensured the tunnel’s successful completion. The IRTS project increases the average local yield of fresh water by approximately 3.4m cu.m per year and enhances flood protection and climate resilience in West Kowloon, setting a high standard for future water management projects.
