Summary of Management Plan

(1) Most of the flood damage reduction measures considered as part of the 1993 Floodplain Management Study cannot be justified on benefit-cost considerations. They could be reconsidered if new information becomes available that leads to substantially increased benefit-cost ratios. Notwithstanding, Option 1E from the 1993 Floodplain Management Study was shown to have a Benefit-Cost ratio of about 0.4 and therefore should be retained within the Plan. This floodplain management strategy involved the voluntary raising of a 39 houses located in areas of Edgeworth, Barnsley and Boolaroo that are potentially flood affected. It is recommended that these houses be re-assessed and prioritised in terms of their suitability for house raising. Once a prioritised list has been determined, steps should be undertaken to implement the strategy. (2) The Flood and Floodplain Management Studies on which this Plan is based should be revisited. The reason for this and the process that should be followed is outlined in Appendix C. The majority of the floodplain management options considered in the 1993 study are either not viable from a cost/benefit perspective or may not be considered appropriate now. Hence, contemporary floodplain management issues need to be determined through consultation with the Committee and key stakeholders within the community. It is not clear whether any consultation took place as part of earlier studies. However, this is considered to be essential to managing future flooding issues that may arise along creek system and its floodplain. This could be achieved by distribution of a brochure similar to that included in Appendix A. (3) Development within areas defined in Figure 4 as 2A, 2B and 2C, should be able to proceed without extensive independent flood investigations, provided all appropriate requirements specified by the current Local Environment Plan are addressed (eg., those related to filling). (4) Development Restrictions Flooding/Tidal Inundation Certificates should be revised to incorporate the predicted peak level of the Probable Maximum Flood or an ‘extreme’ flood. The format of Development Restrictions Flooding/Tidal Inundation Certificates could be modified to provide more information. (5) Further investigations need to be undertaken to determine whether flood damage reduction measures can be implemented for those problem areas listed in Section 4.3.1 (6) Further hydraulic investigations should be undertaken the determine the amount of time before inundation of key areas along Cockle Creek in a typical major flood. (7) A flood liable lands DCP is to be developed specifically for the Cockle Creek catchment. The DCP would effectively serve as a revised Flood Policy and relate to the specifics of flood behaviour in the catchment (as distinct from the lake inundation flood behaviour that applies in other areas of Lake Macquarie City).