Tai Lam Chung Reservoir Waterfall Dam
Side Channel Spillway Model Study

Back one level
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.

spillway.jpg (20691 bytes)
View of spillway from downstream

stilling.jpg (50172 bytes)
Stilling basin and apron




downstream.jpg (27516 bytes)
Down stream river course

channel.jpg (37407 bytes)
Left stepped side channel

flood_sp.jpg (14433 bytes)
Observed Tai Lam Chung spillway for 27.9.93 flood.

model_sp.jpg (13475 bytes)
Observed spillway flow for 27.9.93 flood.

flood_ch.jpg (14826 bytes)
Observed flow in left side channel for 27.9.93 flood

model_ch.jpg (17903 bytes)
Observed flow in right side channel for 27.9.93 flood

crest.jpg (15070 bytes)
Spillway flow over central weir sections at PMF

model_spil2.jpg (14153 bytes)
Oblique view of cross-currents and jet splashing in side channels at PMF

channel1.jpg (11986 bytes)
Observed flow in left channel at PMF

channel2.jpg (13905 bytes)
Observed flow in right channel at PMF

channel3.jpg (11226 bytes)
Side view of air-water flow over the steps of the right side channel