Bonnie Doon Drainage Catchment Flood Study (Pipe and Overland 2D)

| The Bonnie Doon Drainage Catchment is located within the Rockdale City Council Local Government area and drains the suburb of Arncliffe to the Cooks River. The catchment area encompasses approximately 1.1 square kilometres, bounded generally by Forest Road to the South, Wolli Creek Road to the West, Cooks River to the east and Willington, Knoll and Lusty Streets to the north.\r\n\r\nIn the past flooding in the Bonnie Doon catchment has caused considerable property damage. The cost of property damage and the inconvenience to residents by such flooding has prompted Rockdale City Council to prepare a comprehensive and integrated Floodplain Management Plan for the Bonnie Doon Catchment. This is part of the State Government's program to manage major flood impacts and hazards in the floodplains, in accordance with the State Government's Floodplain Development Manual,1986.\r\n\r\nThe first step in the process of preparing a Floodplain Management Plan is the undertaking of a detailed Flood Study for the storm drainage system and associated floodplain of the Bonnie Doon Drainage Catchment. Rockdale City Council requested Lawson and Treloar Pty Ltd (L&T) to undertake a flood study of the catchment to determine the flood behaviour for the 1%, 2%, 5%, 10%, 20% annual exceedance probability (AEP) and extreme flood events. In accordance with the study objectives, the study will determine the nature and extent of flooding through the estimation of design flows, levels and velocities.\r\n\r\nThe objectives of the Flood Study were to:\r\n\r\n* Identify all the flood related data by searching all relevant data sources.\r\n* Determine the likely extent and nature of historical flooding by reviewing the previously compiled survey of residents in the catchment.\r\n* Define existing flood behaviour of the Bonnie Doon Drainage catchment at the highest obtainable level of accuracy.\r\n* Define design flood levels, velocities and flow distributions for the Bonnie Doon Drainage catchment.\r\n* Estimate flood wave travel times for the flood peak at representative locations in the catchment.\r\n* Map extent of flooding for the 1% AEP and Probable Maximum (extreme) Floods (PMF) for the Bonnie Doon Drainage catchment.