General
The study area is located on the lower North Coast of NSW, and includes areas on the Tomaree Peninsula and Tilligerry Peninsula, located on either side of Tilligerry Creek
Flooding in the study area is complex and during major events, floodwaters can interact with the Hunter River, Fullerton Cove and Tilligerry Creek, all of which have tidal influences and also contribute to flooding. This flood study involves the development and calibration/verification of hydrologic models and hydraulic models to determine the nature and extent of flooding in the area.
Purpose of this Flood Study
The purpose of this study is to investigate the existing and future flood risks in the study area and to provide information for the development of the subsequent floodplain risk management study and plan in accordance with the NSW Government’s Floodplain Development Manual.
Objectives
-
Develop and calibrate/verify hydrologic and hydraulic models for the estimation of overland and mainstream flood behaviour in the study area, taking into account the influence and interaction of the various flooding mechanisms in the study area. The models are also to consider the performance of floodgates, hydraulic structures and the stormwater drainage network including overflows from the
drainage network.
-
Determine and describe design flooding behaviour and flood risk in the study area under the full permissible level of development and for current climate conditions, for a range of flood events between the 20% Annual Exceedance Probability (AEP) event and the Probable Maximum Flood (PMF) event.
-
Assess the sensitivity of flood behaviour to changes in hydrologic and hydraulic characteristics in the catchments.
-
Assess the impact of climate change on flood levels in the study area.
-
Mapping of flooding characteristics (depth, level, velocity), flood hydraulic and hazard categories.
-
Determine the Flood Planning Level (FPL) and Flood Planning Area (FPA), based on the 1% AEP event under future climate conditions – 2100 sea level rise (+0.9m above existing) and 20% increase in rainfallintensity.
-
Identify the flood emergency response categories for different parts of the catchment and community.
-
Identify and describe key flood problem areas, including potential mitigation.
-
Analyse potential mitigation options for selected flood problem areas.
The outcomes from this flood study will form the basis for the identification, assessment and prioritisation of management measures during the subsequent floodplain risk management study and plan.
