Mount Cotton – Natural Hazards and Critical Infrastructure

Mount Cotton – Natural Hazards and Critical Infrastructure

Natural Hazards

To view Natural Hazard mapping layers for bushfire, flood and storm tides, or landslides visit the Redlands Coast Disaster Dashboard.

Bushfire

Mount Cotton has a significant bushfire risk with the majority of the Mount Cotton region being classified as having a high to very high bushfire hazard. The large rural properties in the Mount 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 1km long) which impacts the ability to evacuate those properties should a bushfire cut driveway access to the road.

Mount Cotton Village along Valley Way is a pocket of urban development surrounded by high to very high bushfire hazard areas. Although this area does not indicate a bushfire hazard, the location of the housing lends itself to the risk of ember attack from the surrounding areas. During a wildfire, embers can travel up to 3km in front of a fire line which means that all dwellings within the Mount 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 to create your Bushfire Survival Plan – PREPARE.ACT.SURVIVE.

Along with threatening homes, a bushfire in the Mount Cotton area is likely to impact major power, water, wastewater and telecommunications infrastructure which will have flow on effects for the rest of Redland City. In addition to this, Mount Cotton is home to substantial industry in the form of large quarrying operations, numerous poultry farms and the Golden Cockerel processing 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 on Council owned land and impact to surrounding areas. These strategies include hazard reduction burning (back burns), fire breaks and weed management.  Redland Council works with its Local Disaster Management Group partners to undertake fire mitigation activities around the city.

Flood Prone, Storm Tide

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

The Upper Tingalpa Creek starts in the west Mount Cotton hills and the Venman Bushland National Park reserve land as many small meandering ephemeral streams. Wallaby and Buhot Creeks are tributaries and there are many more unnamed tributaries of Tingalpa creek. Tingalpa Creek flows into Leslie Harrison Dam, a major water supply dam connected to the south-east Queensland water grid.

Eprapah Creek is about 52km long and is made up of a main channel and two smaller tributary channels – Little Eprapah and Sandy Creeks. The creek starts at the Mount Cotton hills west of Mount Cotton road, flows through cleared rural blocks and east towards the lower, urbanised reaches of Victoria Point. Eprapah Creek catchment covers the western edges of Victoria Point and Redland Bay and the majority of Mount Cotton. West Mount Cotton Road forms part of the western catchment boundary. The catchment also has many smaller parcels of bushland refuges and Eprapah Creek corridor conservation land.

Native Dog Creek and tributaries flows off the eastern side of Mount Cotton, through Mount Cotton Village and lakes, then south into the lower reaches of Logan River. The upper western portion of the catchment is dotted with many farm dams, poultry farms and lifestyle blocks. The eastern and northern portions are mainly reserve land and covered with bushland. Only one third of the catchment area (upper catchment) is within Redland City boundary. The remaining two thirds is in Logan City. The catchment is bounded by Logan River to the south and Eprapah Creek catchment to the north.

Serpentine Creek rises in the Days Road Conservation Area and flows south into the lower reach of Logan River. The Creek is bound by Moogurrapum catchment to the north, Southern Redland Bay catchment to the east and Native Dog catchment to the west. Two thirds of the catchment is National Park or Reserve land. Key natural features on public land include Days Road, Kidd Street and Serpentine Creek Conservation Areas along with Bay View Conservation Park.

Landslide

The majority of the Mount Cotton region has a level of landslide hazard attributed to it. The area located between West Mount Cotton Road and Mount 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 City Plan, 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.

Plants and tree roots help to prevent landslides occurring by absorbing water and holding the ground together. After bushfires, heavy rain combined with a loss of plants and roots can make the ground soft and heavy, leading to a greater chance of landslides. Landsides can carry debris such as rocks and trees downhill and cause serious damage to anything in their path. The risk of a landslide occurring in a burnt area depends on the volume of rainfall, how steep the land is, the amount of remaining vegetation to support the land, the soil composition and the structure of rocks below the surface. QFES assess landslide prone areas after a significant bushfire to determine if there is a landslide hazard risk.

Critical Infrastructure

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

Sewerage

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

The rural areas of Mount 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. Many of the RCC sewage pumping stations have fixed generators onsite to provide backup power in the event of a power failure. Those that do not have fixed generators have the facilities to plug in a portable generator; several are available that can be taken to any site that requires it.

Water

Mount Cotton is critical in terms of potable water distribution to Redland City. Redland City is connected to the SEQ Water Grid via a pump station on Gramzow Road, Mount Cotton which allows water to be pumped to and from the city. This pump station connects to the Heinemann Road Reservoir at Mount 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 Mount Cotton Reservoir at Tallow Wood Court, which services Mount Cotton and Sheldon. The Mount Cotton Reservoir in turn is connected to the Alexandra Hills Reservoir located at Alexandra Circuit, 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 Mount 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

Mount 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 Mount 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 Mount Cotton Road and the other west of Mount Cotton Road through bushland passing Barro Quarry and the Golden Cockerel plant to intersect another at Seaview Road opposite Mount Cotton State School. From this point, one 33kV above ground powerline network runs north along Mount 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.

A portion of Mount Cotton is relatively new residential development, therefore the majority of the powerline network that services the residential areas is underground reducing the risk of fallen powerlines during severe storms.

There are overhead powerlines in the area that are more susceptible to damage during severe weather which can result in power outages and fallen powerlines. Fallen powerlines can cause significant dangers to the community, so be aware that any object in contact with powerlines could be live. The surrounding fallen powerlines is more dangerous in wet conditions as sea and tap water are an excellent conductor of electricity.

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 000 or Energex on 13 19 62.

Gas

There is no domestic reticulated gas service within Redland City and there is no gas main that runs through the suburb of Mount Cotton. There are however, homes within the area that use gas bottles to 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 Mount Cotton are connected via landlines to the telecommunications and data networks. There is a mobile network established at Mount 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 Mount 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 ABC 612 AM and Bay FM 100.3 which provide emergency updates and alerts via radio to Redland City residents. It is critical that this essential communication infrastructure is protected during a disaster event.

Connection to the National Broadband Network (NBN) is now available across the majority of Australia, with various connection types for both wired (copper, fibre optic, and hybrid fibre-coaxial) and radio (satellite and fixed wireless). It is important to know the type of connection you have; fibre to the building (FTTB), fibre to the curb (FTTC), fibre to the node (FTTN), fibre to the premises (FTTP), or hybrid fibre-coaxial (HFC), there is also satellite or fixed wireless. The majority of connections are FTTN and FTTP, closely followed by HFC.

It is important to note that any equipment connected via the NBN will not work during a power outage, including VOIP (Voice over Internet Protocol) phones. For more information about what happens in a power blackout for the type of connection at your residence, please go to https://www.nbnco.com.au/learn/what-happens-in-a-power-blackout. Certain connection types can request battery back-up solutions through their internet service provider; battery back-up is required for all Priority Assistance customers who suffer from a diagnosed life-threatening illness.

If you have a medical alarm, emergency call button, autodialler, security alarm, monitored fire alarm or lift emergency phones at your premises, please contact your equipment provider to confirm whether your equipment will work via the network in the event of a power outage. Further information is also available on the NBN website and how to register these devices; this assists the NBN in identifying premises where support maybe be required to minimise service outages https://www.nbnco.com.au/learn/device-compatibility.

Road Network

REMEMBER: If it’s flooded, forget it – BACK IT UP!

Summer months bring rain, cyclones and unstable weather conditions to Queensland. More than half of flood related deaths in Queensland are the result of people driving through floodwater. 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. See a list of the areas that may be impacted by localised flooding.

Don’t wait until it’s too late. Plan ahead and keep yourself, family and friends safe. Check out the Queensland Government’s ‘Back it Up’ initiative for more information.

Rail Network

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