IAHR, founded in 1935, is a worldwide independent member-based organisation of engineers and water specialists working in fields related to the hydro-environmental sciences and their practical application. Activities range from river and maritime hydraulics to water resources development and eco-hydraulics, through to ice engineering, hydroinformatics, and hydraulic machinery.
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You are here : eLibrary : IAHR World Congress Proceedings : 35th IAHR Congress - Chengdu (2013) : THEME 8 - CLIMATE CHANGE AND HAZARD MITIGATION : Numerical Determination and Design Optimization of the Drainage System for Happy Valley Flood Protec...
Numerical Determination and Design Optimization of the Drainage System for Happy Valley Flood Protection Scheme, Hong Kong, China
Author : Karen K.Y. Chan and Kevin Chan
Combating flooding against urbanization has long been a challenge in many densely populated cities. While drainage improvement by conventional pipe amplification is a direct flood relief alternative, many aspects of disturbance to the public during construction are considered inevitable in view of various site constraints that are intrinsic to most urban areas. As part of an integrated flood alleviation strategy in Happy Valley of Hong Kong, the Happy Valley Underground Stormwater Storage Scheme (HVUSSS) is adopted to minimize the potential vulnerability of the city?s social-economic growth to flood risk. To ascertain the effectiveness of flood attenuation by the stormwater storage scheme, 1-dimensional and 2-dimensional computational hydraulic modelling of the drainage network and overland flow are adopted to assess the extent of flood risks under various rainstorm events. Combining engineering intelligence with modern technology, the design of the HVUSSS was optimized to obtain a robust and sustainable flood control solution with acclimatization to the effect of climate change. The HVUSSS comprises several major components including an inlet structure, a twin cell diversion box culvert, an automatic movable overflow side weir system, an underground storage tank and a pump house. Particular attention has been given to minimising both the volume and depth of the underground storage tank to achieve a more economical and sustainable design for construction and operation in long-term. Without adopting the traditional fixed crest weirs, the automatic movable crest weirs use real-time water levels measured at the upstream and downstream as the basis to adjust their levels for controlling the timing and amount of stormwater flowing from the twin cell diversion box culverts to the storage tank. Hence, early spillage into the tank could be avoided which could help reducing the required volume of the storage tank by 30%. To enhance the saving of energy consumption and recurrent costs of discharging water from the storage tank after rainstorm events, the tank has been designed shallow enough to allow most of the stored water to be discharged by gravity via the automatic movable crest weirs from the tank to the box culvert. This paper discusses the design and computational hydraulics aspects of the Happy Valley Flood Protection Scheme in Hong Kong. In particular, the adoption of the latest technique of 3-dimensional Computational Fluid Dynamics in the hydraulic analysis to optimize the design will be elaborated.
File Size : 1,107,913 bytes
File Type : Adobe Acrobat Document
Chapter : IAHR World Congress Proceedings
Category : 35th IAHR Congress - Chengdu (2013)
Date Published : 19/07/2016
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