Upper Parramatta River Catchment Floodplain Risk Management Study

#THE STUDY AREA\r\nThe Upper Parramatta River catchment covers an area of 110 square kilometres and\r\ncovers all land that drains to the Parramatta River upstream of its tidal limit at the\r\nCharles Street Weir, between the Barry Wilde Bridge (Wilde Avenue) and the Gasworks\r\nBridge (Macarthur Street). Most of the catchment is urbanised and has a population of\r\nmore than 230,000. However, there are significant areas of urban bushland, generally\r\nlocated along the major watercourses.\r\n\r\nA map of the study area is presented as Figure 1.1. The Upper Parramatta River has\r\na number of tributaries that flow into it within the study area. The two largest tributaries\r\nare Toongabbie Creek and Darling Mills Creek. Other tributaries include the following:\r\n\r\n* Brickfield Creek;\r\n* Domain Creek;\r\n* Finlaysons Creek;\r\n* Coopers Creek;\r\n* Pendle Creek (also known as Pendle Hill Creek);\r\n* Greystanes Creek (also known as Girraween Creek);\r\n* Grantham Creek;\r\n* Blacktown Creek;\r\n* Lalor Creek;\r\n* Quarry Creek;\r\n* The Quarry Branch (also known as Northmead Gully);\r\n* Excelsior Creek;\r\n* Blue Gum Creek;\r\n* Rifle Range Creek;\r\n* Hunts Creek.\r\n\r\nThe Upper Parramatta River catchment includes parts of the following four local\r\ngovernment areas (LGAs):\r\n\r\n* Shire of Baulkham Hills — including the suburbs of Oatlands, Carlingford, North\r\nRocks, Northmead, North Parramatta, West Pennant Hills, Castle Hill and\r\nBaulkham Hills;\r\n* City of Blacktown — including the suburbs of Toongabbie, Seven Hills, Prospect,\r\nBlacktown, Lalor Park and Kings Langley;\r\n* City of Holroyd — including the suburbs of Westmead, Wentworthville, South\r\nWentworthville, Greystanes, Pendle Hill, Girraween, Prospect, Toongabbie and\r\nMerrylands West;\r\n* City of Parramatta — including the suburbs of Parramatta, North Parramatta,\r\nWestmead, Northmead, Wentworthville, Toongabbie, Old Toongabbie and\r\nWinston Hills.\r\n\r\n#OBJECTIVES OF THIS STUDY\r\nThe primary objective of the current Upper Parramatta River Floodplain Risk\r\nManagement Study and Plan is to bring together, and place in appropriate context, all\r\npast, current and proposed future activities related to the reduction of flood risk in the\r\ncatchment. In broad terms, the current study has investigated what can be done to\r\nminimise the effects of flooding in the Upper Parramatta River catchment and\r\nrecommended a strategy in the form of a Floodplain Risk Management Plan.\r\nAs mentioned above, despite the expenditure of more than $35 million on flood\r\nmitigation works and measures since 1989, none of the four councils within the area of\r\nthe Trust have adopted a formal Floodplain Risk Management Plan as required by the\r\nNew South Wales (NSW) Government’s Flood Prone Land Policy. This study and plan\r\nconstitute key components of the NSW Government’s floodplain risk management\r\nprocess as outlined in the Floodplain Management Manual (NSW Government, 2001)\r\n(see Section 1.4).\r\n\r\nSome of the objectives of the study include:\r\n\r\n* briefly outlining the hydrological and hydraulic modelling activities that have been\r\nundertaken for the catchment to date;\r\n* briefly reviewing the past, current and future flood-related activities of the Trust\r\nand the four constituent Councils;\r\n* reviewing, in detail, issues relating to planning and development controls within\r\nthe catchment’s floodplains;\r\n* identifying additional floodplain risk management measures that particularly relate\r\nto community awareness about flooding, the release of flood-related information\r\nto the community, flood warning and emergency management;\r\n* developing a mutually agreeable Floodplain Risk Management Plan for the Upper\r\nParramatta River catchment that outlines the best measures to reduce flood\r\ndamage, based on environmental, social, economic, financial and engineering\r\nconsiderations.\r\n\r\n#Report\r\nThe structure of this report is as follows:\r\n\r\n__Chapter 2__ summarises the flood problems, together with the behaviour and\r\nimpacts of flooding in the Upper Parramatta River catchment. Chapter 2 also\r\ndiscusses the modelling of flood flows and flood levels in the catchment;\r\n\r\n__Chapter 3__ provides an overview of the previous flood-related studies and\r\ninvestigations that have been undertaken in the catchment, together with an\r\noutline of the available mapping and survey that has been carried out;\r\n\r\n__Chapter 4__ presents an overview of floodplain risk management measures\r\navailable for dealing with flood problems generally and the methodology used to\r\nassess these management measures in the current study. The large number of\r\nfloodplain risk management measures that have already examined and\r\nimplemented in the catchment are also listed in this chapter;\r\n\r\n__Chapter 5__ discusses possible future floodplain risk management options for the\r\nUpper Parramatta River catchment, particularly flood-related planning and\r\ndevelopment controls, community awareness about flooding, the release of floodrelated\r\ninformation to the community, flood warning and emergency\r\nmanagement;\r\n\r\n__Chapter 6__ lists all the documents referenced in this study;\r\n\r\n__Chapter 7__ provides a bibliography of all studies and investigations that have\r\nbeen undertaken in the catchment since the early 1970s;\r\n\r\n__Chapter 8__ provides a glossary of terms used in this study.