The Permanent Secretary for Development (Works), Mr Wai Chi-sing (back row, third left), and the Director of Drainage Services, Mr Chan Chi-chiu (back row, second left), today (September 5) witnessed the signing of the contract for the major works of the Happy Valley Underground Stormwater Storage Scheme by the Deputy Director of Drainage Services, Mr Tsui Wai (front row, second left), and the President of Chun Wo Construction and Engineering Co Ltd, Mr Derrick Pang (front row, second right).