Noosa Considering Plan To Cope With Climate Change Effects
Noosa Main Beach. Image Credit: Frances Adcock
Noosa Main Beach is tipped to be more severely impacted by rising sea levels in coming years, unless action is taken between now and then.
Storm tidal surges, erosion and hazard maps, detailed in the report titled 'QCoast 2100', will be considered by Council during next week's Ordinary and General Meetings.
Noosa Council is responding to potential climate change risks by undertaking a two-year project to develop a Climate Change Adaptation Plan (CCAP).
The core objectives for the CCAP are to:
• Improve Noosa Council and the community’s understanding of current & future risks from coastal hazards and how they might change through time as a result of climate change;
• Consult with the community clearly and sensitively throughout key stages of the project so the community understands the implications and contributes to the decision making;
• Identify what actions are required to avoid, reduce or adapt to these risks to people, property, assets and the environment;
• Provide mapping & visual products and deliverables that are useful for a range of purposes across Council departments and functions and within the community (e.g. planning scheme, asset management, community awareness, disaster management and financial planning); and
• Provide direction for a coordinated approach for Council and the community to adapt to climate change and coastal hazards.
Overtopping, which happens when the water breaches a dune or coastal barrier is predicted to occur at Noosa Main Beach and Teewah Beach.
The report states that Teewah Beach shouldn't be too badly affected due to the well-established hind dune area.
The effects of overtopping are considered greater at Noosa Main Beach. The report also finds that as the shoreline shrinks as a result of Sea Level Rises (SLR), it is constrained by development in the area. That means action needs to be taken to lessen the predicted impact.
The report suggests that overtopping at Noosa Main Beach may need to be considered further during the options analysis stage of the Noosa CHAP.
The Noosa CHAP Scoping Study Report (BMT WBM 2017) discusses the three ‘categories’ of storm tide hazard that have been considered as part of previous local government scale
(1) ‘Open coast storm tide’ which can lead to inundation of nearshore areas adjacent to beaches. For these locations the combination of tide, surge and wave breaking processes
contribute to the observed water level.
(2) ‘Lower Noosa River catchment storm tide’ which can lead to flooding of areas within the tidal extent of the lower river system. For these locations and in the absence of significant rainfall and catchment flooding, the combination of tide and surge contribute to the observed water level.
(3) ‘Coincident catchment flooding and storm tide’ which can lead to flooding of areas within the tidal extent of the lower river system. For these locations the combination of river flow, tide and surge contribute to the observed water level.
The likelihood of peak storm tide conditions coinciding with peak catchment flooding within the lower Noosa River is expected to be a rare event, that whilst valuable to understand, would be an extreme event and not preferred as a basis for making planning decisions.
The coincident rainfall, river flooding and storm tide hazard was recently assessed by WMA Water for the present-day and 2100 planning horizons.
The 2040 and 2070 planning horizons were subsequently assessed to provide the additional hazard information.
The Noosa CHAP adopts the following sea level rise allowances (relative to present-day mean sea level):
• 2040: 0.2 m
• 2070: 0.5 m
• 2100: 0.8 m
Future climate 2100 scenarios were also reported by Aurecon (2013). These assessments simply added a 0.8 m SLR allowance to the current climate design water levels.
Current climate and future climate open coast design water levels adopted for the Noosa CHAP storm tide hazard mapping are provided in Table 2-2 below.
Table 2-2 100 year ARI Open Coast Storm Tide Levels (mAHD)
Location Current 2040 2070 2100
Peregian Beach 2.97 3.17 3.47 3.77
Marcus Beach 3.01 3.21 3.51 3.81
Sunshine Beach 3.17 3.37 3.67 3.97
Noosa Head 3.17 3.37 3.67 3.97
Noosa Main Beach 2.62 2.82 3.12 3.42
Noosa River Entrance* 1.63 1.83 2.13 2.43
Noosa North Shore 2.73 2.93 3.23 3.53
Teewah Beach 3.18 3.38 3.68 3.98
*wave setup not included within river entrance