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You are here : eLibrary : IAHR World Congress Proceedings : 35th IAHR Congress - Chengdu (2013) : THEME 4 - HYDRO-ENVIRONMENT : Operating Experience of Inflatable Dam for Pollution Control in Deep Bay, Hong Kong, China
Operating Experience of Inflatable Dam for Pollution Control in Deep Bay, Hong Kong, China
Author : S.K. SHE, S.H. WONG and Gigi W.C. POON
Inflatable dams have been adopted for pollution control in urban streams in Hong Kong. The dams have served the purpose satisfactorily by preventing organic suspended particles from the polluted tidal backflow entering the streams in which odor is generated when these organic pollutants are decomposed under anaerobic condition at the bottom of the stream. With an automatic deflation response to an increase in flow rates under a heavy rainfall, the dams do not pose higher flooding risk to the community. In recent years, there is a paradigm shift in stormwater management in which more focus is placed on eco-hydraulics and low carbon footprint (Wenger et al., 2009; Brown and Farrelly, 2008). Therefore, it is time to review the need and the operation mode of these inflatable dams so that the operation not only meets the objective of pollution control, but also enhances the ecological value of the stream and reduces energy consumption. As measures for achieving these multiple targets are sometimes contradictory, it is not easy to reach the right balance which is dynamic in nature and also site specific, with limited information on flow, ecology, and pollution loading. This paper presents a review of the operating experience of three inflatable dams in urban streams, namely the Yuen Long Bypass Floodway (YLBF), Ngau Tam Mei Nullah (NTMN) and Yuen Long Nullah (YTN). Although they are very close to each other and discharge into the same estuary, Deep Bay in Hong Kong, the site specific conditions would affect the need and the operation of the dam. The YLBF is an engineered channel to divert upstream runoff away from Yuen Long town center for flood prevention. For the purpose of energy saving, the frequency on dam deflation and bypass pumping has been reduced. It satisfactorily achieved annual electricity saving of 100,000kWh, and thus corresponding 70tCO e emission. The 2 inflatable dam for the NTMN was damaged incidentally a few years ago and it was beyond repair. The broken dam, however, has re-established the connection between the stream and the bay, and thus enhancing the ecological value of the stream. Lastly, the YLN running through the Yuen Long town centre is a candidate for revitalization of urban stream for the community. The findings of a detailed investigation with stakeholder engagement suggest that only a section of the nullah in the town center could be revitalized at this stage, and the existing inflatable dam should be maintained to prevent the pollution from Deep Bay.
File Size : 535,419 bytes
File Type : Adobe Acrobat Document
Chapter : IAHR World Congress Proceedings
Category : 35th IAHR Congress - Chengdu (2013)
Article : THEME 4 - HYDRO-ENVIRONMENT
Date Published : 18/07/2016
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