2021-11-15 GC Agenda - Item 7 - Attachment 2 - Coastal Hazards Adaptation Plan with tracked changes

NOOSAVILLE
Setting
The Noosaville locality is a vibrant urban setting defined by watercourses and bushland edges
including the Noosa River, Eenie Creek, Lake Weyba, and Noosa National Park. Noosaville
provides much of the commercial, retail, administrative, industrial and social needs of the coastal
urban portion of Noosa Shire and is a major focus area for visitor accommodation and services.
The Noosa River foreshore adjacent to Gympie Terrace is an important recreational space for the
local community and visitors. The area is popular for passive recreation, walking, dog exercise and
access to the Noosa River including ferry stops.

Noosaville is topographically quite flat with much of the locality having an elevation of only a few
meters above present-day high tide levels. For this reason, low-lying parts of Noosaville already
see inundation at king tides, and “daylight flooding” (due to overflowing stormwater systems) after
heavy rainfall events.

Risks to Noosaville
Significant areas of Noosaville adjacent to the Noosa River and other waters areis considered at
high to very high risk from tidal inundation by the end of the planning period. The low topography of
the locality means many assets are likely to be exposed to frequent inundation. The most
prominent of these are publicly owned assets, namely foreshore recreation areas, the road network
(including footpaths) and the gravity-based stormwater network. Some residential lots are
projected to be partially inundated, though this is unlikely to include the dwellings themselves, only
gardens and driveway areas. A small number of tourism and commercial operations may also be
affected by inundation. Environmental values present across natural foreshore areas of the river39
and the conservation parks will be affected.

Appendix 3 shows the change in risk profile across various parts of Noosaville as the area exposed
to the effects of periodic tidal inundation increases over time. Table 1819 provides a summary of
the changing risk profile for six broad asset types within the locality that are projected to be
exposed to the effects of periodic tidal inundation between present day and 2100.

The most significant concerns in this locality relate to the risks to foreshore parks, given the
reliance of locals, visitors and adjacent businesses alike on them to create safe and attractive
places to spend time. Some areas of Quota and Apex Parks are can almost certainty expect to be
inundated under normal tidal conditions to depths of 10cm for at least 1 hr per day for up to 300
days per years. The exposure of Council-managed infrastructure, in particular the stormwater
network, is of significant concern as this network already affected by intrusion of saline tidal waters
onto the stormwater pipes. As sea levels increase, this is expected to occur on a daily basis.

This salt watersaltwater intrusion presents two key problems. Firstly, the salt watersaltwater may
damage assets that are not expected to be regularly exposed to salt watersaltwater and these
waters may lead to sedimentation of the network. Secondly, the network is designed to carry a
specified volume of overland flows of water during rainfall away from developed areas and into the
Noosa River. If the network capacity is taken up by tidal waters, these overland flows cannot enter
the network and flow out the river, thus potentially leading to some increased flooding in the road
network during minor rainfall events. From mid-century onwards, it is very likely that tidal waters
may flow back up the network and into the street even under sunny day conditions. As a result,
both of these scenarios may create nuisance and disruption to the community, health and safety
risks to residents and visitors, as well as possibly leading to minor damage to public and private
assets.




39 Including Keyser Island, Hay Island, and Ross Island.


Noosa Council – Coastal Hazards Adaptation Plan                                                Page 71