Mount Cotton – Natural Hazards and Critical Infrastructure

Mount Cotton – Natural Hazards and Critical Infrastructure

Natural Hazards

Bushfire

Mt Cotton has a significant bushfire risk with the majority of the Mt Cotton region being classified as having a high to very high bushfire hazard. The large rural properties in the Mt Cotton area including the Ridgewood Downs Estate are at greater risk due to the nature of those properties being heavily wooded. The risk is further compounded for those properties where the home is set back deep into the property with long single access driveways (some up to 1 kilometre long) which impacts the ability to evacuate those properties should a bushfire cut driveway access to the road.

Mt Cotton Village along Valley Way is a pocket of urban development surrounded by high to very high bushfire hazard areas. Whilst the development area does not indicate a bushfire hazard, the location of the development lends itself to the risk of ember attack from the surrounding areas. During a wild fire, embers can travel up to 3 kilometres in front of a fire line which means that all dwellings within the Mt Cotton area are at risk. Residents need to be vigilant and be prepared. For more information about bushfire preparedness and what to do during a bushfire, visit the Queensland Rural Fire Service website and download the Bushfire Survival Plan – PREPARE.ACT.SURVIVE.

Along with threatening homes, a bushfire in the Mt Cotton area is likely to impact major power, water, wastewater and telecommunications infrastructure which will have flow on affects for the rest of Redland City. Furthermore, Mt Cotton is home to substantial industry in the form of large quarrying operations, numerous poultry farms and the Golden Cockerel plant, all of which would be impacted by bushfire.

Redland City Council employs a range of fire mitigation strategies to reduce the risk of bushfire in the area. These strategies include hazard reduction burning (back burns), fire breaks and weed management. Redland City Council is also investigating arrangements with Queensland Fire and Emergency Services to support fire mitigation activities around the city.

Download the Mount Cotton Bushfire Prone Map.

Flood Prone, Storm Tide

Mt Cotton has an extensive network of creeks originating from the Mt Cotton ridgeline and running both west across West Mt Cotton Road into Venman National Park and east toward Moreton Bay crossing Mt Cotton Road at a number of points. These creek systems have the potential to cause some localised flooding in the Mt Cotton area during heavy rain events and severe weather. Mt Cotton Road, just south of Woodlands Drive has been identified as an area with a history of localised flooding.

Download the Mount Cotton Flood Prone, Storm Tide Overlay.

Landslide

The majority of the Mt Cotton region has a level of landslide hazard attributed to it. The area of Mt Cotton located between West Mt Cotton Road and Mt Cotton Road is identified on current mapping as having high to very high landslide hazard. This area is predominantly rural and as such contains large properties and minimal residential development.

The Redland Planning Scheme, through the Landslide Hazard Overlay attempts to mitigate the impacts of the landslide hazard by requiring more robust engineering for developments built within the identified landslide hazard areas. It is important for engineers and geologists to evaluate slope stability and any landslide threat during development assessments so that effective and timely remedial measures can be implemented.

Download the Mount Cotton Planning Scheme, Landslide Hazard Overlay.

Critical Infrastructure

Critical infrastructure at the time of a disaster event includes utilities such as power, water, sewerage, telecommunications, gas and road and rail networks. Impacts of a disaster on these services may have far reaching long term affects for mainland communities.

Sewerage

Mt Cotton has a mix of sewered and non-sewered areas. The primary residential development of Mt Cotton Village which straddles both sides of Valley Way is connected to the city’s sewer network. Effluent from the Mt Cotton area is directed to the wastewater treatment plant on German Church Road, Redland Bay.

The rural areas of Mt Cotton, including the Ridgewood Downs Estate off Sanctuary Drive are not connected to the city’s sewer network and rely on a mix of gravity fed septic systems and on-site sewerage treatment plants located on the properties to manage the wastewater. The on-site sewerage treatment plants require electricity to function, therefore it is recommended that these systems have a back-up generator to cope with extended periods of power outages which can occur during severe weather events.

Water

Mt Cotton is critical in terms of potable water distribution to Redland City. Redland City is connected to the South East Queensland Water Grid via a pump station on Gramzow Road, Mt Cotton which allows water to be pumped to and from the city. This pump station connects to the Heinemann Road Reservoir, Mt Cotton which is also connected to Herring Lagoon on North Stradbroke Island ensuring two sources of water to the southern end of the city.

The Heinemann Road Reservoir services the Southern Moreton Bay Islands, Redland Bay, Victoria Point and Thornlands and is also connected to the Mt Cotton Reservoir at Tallow Wood Court, Mt Cotton which services Mt Cotton and Sheldon. The Mt Cotton Reservoir in turn is connected to the Alexandra Hills Reservoir located at Hilltop Circuit, Alexandra Hills making possible the supply of water to Redland City’s northern suburbs should there be issues with Leslie Harrison Dam which traditionally services the north of the city.

There are a number of rural properties in the Mt Cotton area with large dams that act as an independent water source for those residents. These dams may provide a potential source of water for aerial water bombing operations should they be required.

Electricity

Mt Cotton has significant electrical infrastructure passing through it at a number of points. Power supply connection between Logan City and Brisbane City runs via a 110kV above ground powerline from the southern end of Mount Cotton. The powerline travels north through Mt Cotton and Sheldon where it traverses heavily wooded terrain which is characterised as high to very high bushfire risk before crossing Tingalpa Creek into the Brisbane City area.

Second and third 33kV above ground powerline networks run parallel to one another, one along Mt Cotton Road and the other west of Mt Cotton Road through bushland passing Barro Quarry and the Golden Cockerel plant to intersect another at Seaview Road opposite Mt Cotton State School. From this point, one 33kV above ground powerline network runs north along Mt Cotton Road to Woodlands Drive on the border of Sheldon and Thornlands, and the other 33kV above ground powerline network runs east along Giles Road to Redland Bay.

Mt Cotton is a relatively new residential development with further development being planned in the future. Accordingly, the majority of the powerline network that services the residential areas is underground reducing the risk of fallen powerlines during severe storms.

However, there are overhead powerline in the area that are more susceptible to damage during severe weather which can result in power outages and fallen powerlines. Fallen powerlines oppose significant dangers to the community, be aware that any object in contact with powerlines could be live. The area is more dangerous in wet conditions as water is an excellent conductor.

Remember: any metallic objects, including fences, will be electrified if they touch or are even close to a live fallen powerline. Even a tree branch can be a potential conductor of electricity if it is in contact with a live wire. Stay away from fallen powerlines and alert others of the danger – contact Energex on 13 19 62.

Gas

There is no domestic reticulated gas service within Redland City. Nor is there a gas main that runs through the suburb of Mt Cotton. There are however homes within the area that use gas bottles the service hot water systems and cooking appliances. Residents are reminded to be diligent with the appropriate storage and maintenance of any gas bottles that they have located on their property.

Telecommunications

The residential areas of Mt Cotton are connected via landlines to the telecommunications and data networks. There is a mobile network established at Mt Cotton however due to the steep terrain of the region, there are likely to be mobile reception black spots in the area. Telstra is the major supplier of telecommunications to the region; other suppliers include Optus and Vodafone.

Emergency service agencies have established communications infrastructure at Mt Cotton which provides radio communications capabilities to their emergency service units throughout mainland Redland City. Positioned along with that communications infrastructure is the broadcasting tower for BayFM and ABC 612 which provide emergency update and alerts via radio to Redland City residents. It is critical that this essential communication infrastructure is protected during a disaster event.

Road Network

REMEMBER: If it’s flooded, forget it!

On 20 November 2012, Iain MacKenzie – Inspector General Emergency Management said “There is absolutely no excuse for motorists who deliberately drive or walk past a road closed sign and into floodwaters. Even if you are in familiar territory and believe local knowledge will get you through, think again. Floodwaters are treacherous and the dangers are hidden beneath the surface.”

Every year people are hurt, or die, trying to cross or play in flooded waterways. It can happen anywhere – roads, creeks, dams, parks or backyards. Residents should be aware of the dangers connected to floodwater or swift flowing water such as: slippery surfaces; uneven ground; strong currents; sharp objects; electrical current; fences; vehicles; rocks; long grass; tree branches; sewerage; and chemicals.

If you get trapped in floodwater, you not only put your life and the lives of the people with you at risk, but you also put the lives of the rescuers at risk too.
Localised flooding may temporarily restrict access and cut roads in some areas of Redland City. Please consider this when planning to drive during periods of heavy rain. A list of the areas impacted by localised flooding can be found here.

Rail Network

Currently there is no rail infrastructure in Mt Cotton and there are no plans to extend the rail network to Mt Cotton in the near future.