The Municipal Affairs Bureau (IAM) attaches great importance to the Commission of Audit’s report on “Construction of the rainwater pumping station and box culvert drain in Northern Inner Harbour” and will actively improve communication with other public departments according to the suggestions in the audit report to jointly accomplish flood management and drainage work.
The Commission of Audit pointed out in the report that, IAM has not applied the standard of rainfall intensity in a 20-year return period in the planning of the rainwater pumping station in Northern Inner Harbour as suggested in “Report on the comprehensive proposal concerning planning of flood (and tide) prevention and drainage in the Inner Harbour and waterfront area of Macao”, and has instead continued to apply the standard of rainfall intensity in a 10-year return period established in the “Regulation of Water and Wastewater Drainage of Macao” in the project design due to inadequate communication with other departments. In this regard, IAM will seriously review the shortcomings existing in its work and continuously strengthen communication with other public departments.
The standard of rainfall intensity in a 10-year return period was used as the lowest standard in the design of the rainwater pumping station in Northern Inner Harbour. The capacity of rainwater collection in the area has been taken into consideration in the planning of the pumping station by IAM and the overall drainage capacity of the completed facilities such as rainwater box culvert drain, drainage pumping station, etc. has surpassed the design standard of a 10-year return period. The facilities are capable of effectively fulfilling the drainage needs of that area during rainfall and rainstorms. In the two years the rainwater pumping station in Northern Inner Harbour has operated, the flooding of the surrounding areas has been reduced while there has been no need to activate all the water pumps in the pumping station for drainage in multiple occasions of adverse weather like heavy rain and typhoons.
Drainage of the urban area is a project of systematic construction and requires the synergy and joint operation of the facilities for water collection, storage, drainage, etc. to achieve the best drainage effect. After the construction of the box culvert drain and the drainage pumping station was completed, successive replacement and expansion of the upstream drainage network in the old areas will be needed in the future to direct the rainwater to the box culvert drain smoothly for timely drainage into the Inner Harbour by the pumping station, so as to fully utilise and exert the flood management and prevention capacity of the rainwater pumping station in Northern Inner Harbour and reduce the impact of flooding on the daily lives of the residents in the area to the greatest extent.