2019-07-09 P&E Agenda - Item 10 - Attachment 1 - Coastal Hazards Risk, Vulnerability and Adaptation Assessment

Noosa Shire Council Coastal Hazard Mapping                                                                  I
Executive Summary




Executive Summary
Priority gap studies identified by the Noosa Shire Council Coastal Hazard Adaptation Plan (CHAP) Scoping
Report (BMT WBM 2017) have been completed, namely:

• Development of storm tide hazard mapping for the CHAP planning horizons (present-day, 2040, 2070
  and 2100); and

• Coastal erosion prone area assessment and mapping for the CHAP planning horizons.

BMT WBM (2017) discusses the three ‘categories’ of storm tide hazard that are relevant to the region:

(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.

Hazard areas related to each of the above storm tide categories have been developed using a combination
of existing information and inundation modelling tools (Aurecon 2013; WMA Water 2017a; WMA Water
2017b). For land adjacent to the lower Noosa River both inundation depth and velocity hazard information
has been determined.

In accordance with the Queensland Government Coastal Hazard Technical Guide (DEHP, 2013), the open
coast calculated erosion distance has been refined through consideration of the design storm conditions,
dune slumping, long term recession and the shoreline response to sea-level rise. In addition, and for
consistency with the State-defined erosion prone areas, the permanent tidal inundation due to sea-level rise
hazard area has also been established.

These hazard maps will be used to support future consultation with the community and a risk assessment
process; in combination, these will then inform the consequences of these hazards to assets and future
strategic planning in response.




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