Introduction Cardno were commissioned by Shoalhaven City Council to undertake the Floodplain Risk Management Study and Plan for the Broughton Creek catchment. The catchment is approximately 518 km2 in size and surrounds the township of Berry on the NSW south coast. The study has been undertaken to define the existing flooding behaviour and associated hazards, and to investigate possible mitigation options to reduce flood damage and risk. The tasks were undertaken alongside community consultations to ensure that community concerns were addressed. In the past, flooding in the catchment has caused property damage and posed a hazard to residents. Significant flood events occurred in 2011, 2005, 2002, 1988 and 1974. A flood study was previously prepared that identified the flood behaviour in the study area (SMEC, 2008). An update has subsequently been undertaken in this study to improve the definition of the flood behaviour in the Berry Township, and in the areas immediately adjacent to the township. Details on the update and outcomes of the study are provided in Appendix B through Appendix E. Flooding was assessed for the 50% AEP, 20% AEP, 10% AEP, 5% AEP, 2% AEP and 1% AEP events, as well as the Probable Maximum Flood (PMF). Flood levels, depths and velocities were determined, as well as provisional hazard categories, and hydraulic categories. From the base case results, a number of flood mitigation options were examined to manage flooding within the Broughton Creek catchment. The identification and examination of these options was done in accordance with the NSW Government Floodplain Development Manual (NSW Government, 2005).

Cardno were commissioned by Shoalhaven City Council to undertake the Floodplain Risk Management Study and Plan for the Nowra and Browns Creeks catchment. The study has been undertaken to define the existing flooding behaviour and associated hazards of the study area, and to investigate possible mitigation options to reduce flood damage and risk. The tasks were undertaken alongside community consultation to ensure that community concerns were addressed. This report details the proposed implementation strategy for the flood risk management options identified in the Floodplain Risk Management Study (Cardno, 2015).

Report; Stage reports; Costings.

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Introduction The Dora Creek Flood Risk Management Plan has been prepared for Lake Macquarie City Council (Council) in accordance with the NSW Floodplain Development Manual (April 2005 - Reference 1) and the August 2010 Flood Risk Management Guide – Incorporating sea level rise benchmarks in flood risk assessment (Reference 4) and: Is based on a comprehensive and detailed evaluation of factors that affect and are affected by the use of flood prone land; Represents the considered opinion of the local community on how to best manage its flood risk and its flood prone land; and Provides a long-term path for the future development of the community. The Dora Creek catchment is located on the western side of Lake Macquarie waterway, 30 km south-west of Newcastle and 120 km north of Sydney. Dora Creek has a catchment area of approximately 238 km2 and is the largest catchment flowing into the Lake Macquarie waterway which has a total catchment of 648 km2 (Figure 1). The study area focuses on the existing township of Dora Creek and includes the townships of Cooranbong and Avondale, where new and planned rural and urban developments are proposed within the floodplain. The upper limit of the study area extends above Freemans Drive to Cooranbong and downstream to the confluence of Dora Creek with the Lake Macquarie waterway. There are three main tributaries within the catchment with Dora Creek being joined by Jigadee Creek at Cooranbong and then Stockton Creek before draining into Lake Macquarie waterway at Bonnells Bay and Lake Eraring. Watercourses within the catchment area and above the tidal limit are narrow; Dora Creek is typically less than 15 m wide upstream of Freemans Drive. Below the tidal limit, the creeks become broader with Dora Creek varying from a width of 50m at the Sydney to Newcastle Freeway to 100m where it forms a delta into Lake Macquarie waterway. Upstream of the delta the Eraring Power station draws cooling water for steam condensation from Bonnells Bay, which passes under Dora Creek through a concrete tunnel and open canal.

Introduction A Floodplain Risk Management Study (FRMS) and Floodplain Risk Management Plan (FRMP) for the Broughton Creek catchment has been prepared by Cardno for Shoalhaven City Council. The Study identifies and examines options for the management of flooding within the Broughton Creek catchment floodplain. This Plan takes the recommendations from the Study and incorporates them into a plan of implementation. Both studies have been prepared in accordance with the NSW Government Floodplain Development Manual (2005).

Indirectly affected area; Low flood island; Low trapped perimeter area; Overland escape route; Rising road access.

Survey, brochure, workshop, public exhibition

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