Tai Lam Chung Reservoir Waterfall Dam
Side Channel Spillway Model Study
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Located in Tuen Mun, New Territories, the Tai Lam Chung Reservoir has a direct catchment area of 16.5 km2, with a Probable Maximum Flood (PMF) of 703 m3/s. Flood flows are discharged over a concrete gravity dam side channel spillway with a crest length of 138m. In order to safeguard downstream developments, a physical and mathematical modelling study of the spillway has been carried out in the hydraulic laboratory of the civil engineering department, University of Hong Kong, to determine:
  • the head discharge relationship of the spillway,
  • the  flow characteristics of the spillway and capacities of the side channels for various flood conditions.

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View of spillway from downstream

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Stilling basin and apron

 

 

 

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Down stream river course

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Left stepped side channel

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Observed Tai Lam Chung spillway for 27.9.93 flood.

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Observed spillway flow for 27.9.93 flood.

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Observed flow in left side channel for 27.9.93 flood

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Observed flow in right side channel for 27.9.93 flood
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Spillway flow over central weir sections at PMF

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Oblique view of cross-currents and jet splashing in side channels at PMF
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Observed flow in left channel at PMF

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Observed flow in right channel at PMF
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Side view of air-water flow over the steps of the right side channel