Author(s): Jim S. S. Chim; Sylvia S. F. Chan; Harry H. C. Lam; Paul C. K. Chu

Linked Author(s):

Keywords: Flood protection; Hydraulic model; Drainage tunnel; Intakes; Enhancement

Abstract: Being a major strategic flood prevention infrastructure in Hong Kong, Tsuen Wan Drainage Tunnel (TWDT) was one of the drainage tunnels implemented by Drainage Services Department (DSD) of Hong Kong Special Administrative Region to relief the flood risk in the densely-populated areas. A previous analysis by DSD using the hydrological data collected between 2014-2016 revealed that there might be room for improving TWDT's drainage performance. DSD therefore invited Binnies Hong Kong Limited to jointly conduct an in-depth hydraulic study to review the performance of TWDT. The objectives of the study were to (1) review and enhance the flow monitoring system, (2) review the runoff carried by the existing waterworks facilities at the uphill catchment, (3) review the interception performance at the intakes, and (4) propose measures for enhancing the intercepting performance to strengthen the climate resilience of the drainage system. The study suggested a comprehensive flow monitoring system to obtain a water balance for evaluating the drainage tunnel performance, which was followed by adopting hydraulic modelling and computational fluid dynamic (CFD) modelling techniques to review the design assumptions of the hydraulic structures. The approach and assumptions in relation to the uphill waterworks facilities for designing the drainage tunnel were also examined. Factors affecting the intercepting performance and room for enhancing the intercepting performance would be identified. Appropriate improvement measures at the intake structures were then formulated to unleash the full hydraulic potential of TWDT. This case study could set an example for upcoming performance review of other similar drainage tunnels.

DOI: https://doi.org/10.3850/978-90-833476-1-5_iahr40wc-p0168-cd

Year: 2023