The Drainage Services Department (DSD) has completed its investigation into the flooding incident at Sha Po Tsai Village in Tai Po which occurred on July 22 this year. An independent review of the DSD's investigation conducted by a hydraulics expert has also been completed. A summary of the investigation was uploaded to the websites of the Development Bureau (DEVB) and the DSD for public perusal today (October 28).
During the Black Rainstorm on July 22, serious flooding occurred at Sha Po Tsai Village. The Administration is deeply concerned about the incident which resulted in one fatality and damage to property.
After the incident, the Development Bureau directed the DSD to carry out an investigation into the causes of the flooding. The Secretary for Development, Mrs Carrie Lam, appointed an internationally renowned hydraulics expert, Professor Joseph Lee Hun-wei, to conduct an independent review of the investigation report. The DSD's investigation report and Professor Lee's independent review report were submitted to the Development Bureau in August and October respectively.
In the course of the investigation, the DSD conducted a thorough review of the drainage regime around Sha Po Tsai Village, the improvement works completed before July 22 as well as the degrees of blockage and damage to Tai Po River resulting from the flooding event. With the information collected, the DSD constructed a mathematical hydraulic model to assess the effects that the blockages at the bridges, the interim drainage works and the erosion/deposition had on the flooding situation.
Professor Lee carried out an independent review of the DSD's investigation report on the causes of the flooding, the effect of the river training works on the flooding situation, the sources of the coarse sediment, the appropriateness of the construction sequence, and the adequacy of the improvement measures completed or to be carried out by the DSD.
In the course of the review, Professor Lee made site visits, interviewed relevant villagers and collected information on the flooding event, the flooding history of Sha Po Tsai Village, as well as the construction activities of the drainage improvement works. With the information collected, Professor Lee deployed different kinds of state-of-the-art hydraulic modelling techniques developed in hydraulic research in recent years to simulate the flash flood in the incident.
A spokesman for the Development Bureau said the Coroner had instructed the Hong Kong Police Force on July 26 to carry out an investigation and submit a death investigation report to him within six months.
"At the moment, the Administration cannot rule out the possibility of a Coroner's inquest into the fatality. In order not to affect the conduct of a possible death inquest or possible criminal investigation, the investigation report and the independent review report will not be disclosed to the public at this stage," the spokesman said.
"However, the Administration has prepared a summary of factual information which covers the methodology of the DSD's investigation as well as the relief work and improvement measures following the rainstorm. The summary has been uploaded to the website of DEVB (http://www.devb.gov.hk/) and DSD (http://www.dsd.gov.hk/) for public perusal."
Immediately after the flooding incident, the DSD carried out flood relief work to help restore to normal the daily lives of the affected villagers as early as possible.
"The relief work includes reinstating pedestrian accesses and railings, clearing blockages at bridge crossings, and clearing sediment and boulders deposited along the river. In addition, the DSD has assisted the villagers to clean up and repair their houses that had been affected by the flooding.
"The DSD aims to carry out as much improvement work to the Tai Po River as possible in the coming dry season to further raise the level of flood protection prior to the completion of all the drainage works by end 2011," the spokesman said.
The department has also completed a review of its on-going river improvement works in various parts of the territory, and is satisfied that the flow carrying capacities of these rivers will not be adversely affected by their construction works during heavy downpours.
"These river improvement works will not increase the risks of flooding of their works areas. Nevertheless, temporary drainage management plans have been put in place under the respective works contracts to ensure that the flow carrying capacities of the concerned rivers will not be adversely affected by the works," the spokesman said.
Ends/Thursday, October 28, 2010
Issued at HKT 15:01
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