The New South Wales division of the Institute of Public Works Engineering Australia (IPWEA) Excellence for Engineering Awards 2002 attracted a record number of entries, with projects of an exceptionally high standard. The awards were presented at IPWEA – NSW Division’s Annual Conference staged in Coffs Harbour in November.
The Gold Award went to Ryde City Council for the West Ryde Drainage Tunnel. With the existing drainage system largely under buildings, it was found to be too costly and difficult to improve due to necessary disturbance to buildings, roads and parks. As a result, Council constructed a drainage tunnel 2.7 kilometres in length and 3.6 metres in diameter. The construction of the tunnel reduced costs from an estimated $16 million to a final cost of approximately $10 million.
An innovative system of strata subdivision provided easements beneath private property, bringing a minimal loss to property value. The depth of the tunnel also reduced potential noise and vibration impacts during excavation. Waste from the construction was used to raise the level of playing fields at the downstream outlet of the tunnel.
Copmanhurst Shire Council, together with New South Wales fisheries, took out the Special Community Service Award with an innovative fish friendly waterway crossing design in the Clarence River catchment. The existing causeway tended to hinder fish movement. It was replaced with a multi cell box culvert design with a rough base and sidewalls to enhance fish movement.
The roughness was also used to create boundary layers similar to a natural creek. The structure increased the cross sectional area below the roadway and reduced water velocity to that naturally occurring in the creek. A realistic timetable of ten days was agreed with the community, accepting that access would not be available during that period. The project was completed on time and on budget.
