Date, time & venue 
2013-02-02;8:45 am to 13:30 pm;High Island Reservoir (Click the button at top right for gathering point)

Programme Highlights

High Island Reservoir is one of the largest dams in Hong Kong, Construction work commenced in 1971 and was completed in 1979, it provides a capacity of 280 million m^3. Throughout the visit, the participants can understand the construction of High Island Reservoir for water storage and supply for the wellbeing of Hong Kong people. The participants also can learn how the planning, design, construction, and maintenance for the reservoir safety as to arouse young engineer to interest for becoming professional reservoir safety engineer as one of their careers.

Fee: Free of charge

Registration & Enquiries

Seats are limited to 25.

As of 5:30pm 14 January 2013, the number of applicants exceeded the capacity. On-line registration was CLOSED.

The successful applicants will be confirmed on or before 25 January 2013.

For enquiries, please contact Ir. C.S. Lam at 91527659.

CPD certificate will be issued after completion of the visit.

Report

By Miss Elizabeth Leung

The Civil Division organized the captioned visit on 2 February 2013. The visit was led by Ir Lam Chi Sing and Ir Edmund Li, Engineer of the Water Supplies Department (WSD). Ir Li briefed that the purpose of the visit was to raise the participants’ interest in the field of reservoir safety.

At the beginning of the visit, Ir Li introduced to us the history and the background information of the High Island Water Scheme. We were then led to the draw-off tower via the tunnel access. The tower has five levels of intakes. Water drawn from these intakes is transferred to the Shatin Treatment Works for treatment before entering the distribution network. The interior of the tunnel access to the draw-off tower was observed with random fine cracks and seepage on walls.  Some small relief drain holes were formed to avoid the building up of water pressure behind the tunnel walls.

The bell-mouth overflow spillway manages to pass a flood of 396 m³/s at the onset of backwater flow rising to 453 m³/s at a water level of 61.69 mPD. The overflow discharges to a 6m diameter vertical shaft, connected to a tunnel of 5.5 m diameter which discharges directly into the sea shore at a flip bucket in form of a ramped baffle wall.

At the West Col Dam, more than 100 piezometers were installed along the downstream dam face for monitoring of the phreatic surface within the Dam.  The Dam had a history of leakage since impoundment in late 1970s with the leakage rate up to about 480l/min in some occasions. In view of this, investigation and remedial grouting works local to the south end of the Dam were carried out by WSD.  The remedial works were proved successful by the subsequent monitoring records which indicate largely-reduced and steady leakage discharges.

A drainage gallery was constructed within the West Main Dam for collecting possible seepage through the dam core.  Such seepage was gauged at the entrances of the gallery with V-notch plates.  There was also an inverted pendulum inside the gallery for gauging the movement of the dam

Finally on behalf of the Civil Division and the participants, we would like to express our sincere thanks to WSD Reservoir Safety Team for their kind arrangement and presentation.

Photos of the Event

Please visit Photo Album 20130202 High Island Reservoir