The Black Rainstorm Signal issued on May 22 this year had the second longest duration ever recorded in Hong Kong. According to the Hong Kong Observatory, more than 150 millimetres of rainfall per hour were recorded in many places over the territory. Although there were some incidents of flooding, tree collapses and landslides, we were fortunate that severe regional flooding did not occur thanks to the remarkable results of the territory-wide flood prevention projects of the Drainage Services Department (DSD) over the past 10 years or so.
I happened to visit the DSD two days later as previously arranged. Using this Black Rainstorm Signal that lasted five and a half hours as an example, let me briefly explain how the DSD addresses the flooding problems caused by sudden rainstorms. I will illustrate how the DSD reacted when higher levels of rainstorm warning signals were successively hoisted in less than three hours that night, especially the way it tackled the flooding at Tin Sam Village in Yuen Long and the Kwun Tong Road Underpass. It is hoped that this may help you know more about the measures taken by the Government against inclement weather.
In the early hours that day, the Observatory successively issued the Amber, Red and Black Rainstorm Signals as well as the Special Announcement on Flooding in the Northern New Territories. While most of us were still sleeping, 25 DSD colleagues on duty quickly headed for the emergency control centre in Cheung Sha Wan in torrential rain once they had been notified of the Red Rainstorm Signal.
In fact, a working team of the DSD swiftly arrived at Tin Sam Village in Yuen Long to alleviate the flooding problem at 2.15am, more than two hours before the issuance of the Black Rainstorm Signal. Its early arrival was made possible by the DSD’s initiative of stationing a number of working teams at its regional offices across the territory during heavy rainstorms, so that they can inspect the drains and clear blockages immediately after reports of flooding are received to prevent problems from deteriorating. That day, when they were informed of the serious flooding at Tin Sam Village in Yuen Long and the Kwun Tong Road Underpass, they quickly sent colleagues to inspect the situations and help other departments pump out excess water as soon as possible.
The emergency control centre, which was activated shortly after the Black Rainstorm Signal had been issued, is mainly responsible for co-ordinating contractors and instructing them to allocate resources to clear blocked drains quickly in flooded areas, thereby minimising inconvenience to the public. In addition, the centre reported to the relevant government departments every hour on the latest situation of the flooded areas and progress of the flood alleviation work. In the fight against the rainstorm, they dealt with flooding in various parts of the territory with dedicated efforts. I will not go into the details here, but I just want to point out that at the peak of their work, the contractors mobilised some 30 working teams, each equipped with draining tools and pumps, to inspect the flooding spots and carry out emergency work to alleviate the flooding problems under the instruction of the centre.
While all the rainstorm warning signals were cancelled by 10.30am, the emergency control centre remained in operation till 6pm to handle and monitor all the flooding cases until they were all resolved.
Although severe regional flooding did not occur that day, our colleagues did not lower their guard as local flooding, which was mainly caused by the blockage of roadside drains with rubbish or silt, still occurred in some places. Our colleagues worked really hard with other departments to tackle the flooding problems.
Besides addressing the flooding problems, the DSD also attaches great importance to long-term prevention work. The annual average rainfall in Hong Kong is about 2 400 millimetres, one of the highest levels among the cities in the Pacific Rim. Since its establishment in 1989, the DSD has been actively carrying out territory-wide drainage and flood prevention projects, including the river regulation projects in the New Territories and stormwater storage tanks in Tai Hang Tung and Sheung Wan, as well as the drainage tunnels in Western Island, Lai Chi Kok and Tsuen Wan. With the completion of these projects, over 100 flooding black spots have been eliminated. As a result, we are protected against the severe regional flooding that used to plague the low-lying areas in the northern New Territories and some old urban areas during heavy rainstorms in the past.
To keep in line with the future development of Hong Kong, the DSD has commenced the review of the Drainage Master Plans of different districts, and will study the effects on the drainage system of extreme weather due to climate change. In addition to carrying out various flood prevention measures, the DSD will also ensure that the drains are in good condition through proper daily maintenance work.
The DSD will celebrate its 25th anniversary next year, and will continue to take up the challenges ahead presented by increasingly extreme weather and unpredictable rainstorms. I believe that my colleagues will always remain vigilant, diligently perform their duties and stay well prepared to tackle any flooding emergencies. I would like to take this opportunity to express my gratitude to all the DSD colleagues for their outstanding service for more than 20 years, and I hope that we Hong Kong people will all work together to keep our drains clear. Your valuable assistance will certainly make our work possible.
2 June, 2013
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