Alexandra Hills – Natural Hazards and Critical Infrastructure

Alexandra Hills – 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

Alexandra Hills is predominantly a residential area that encompasses large bushland areas to the east and south-west of the suburb. Located in the vicinity of Hanover Drive and Nanette Court is the Cleveland Wastewater Treatment Plant and the Alexandra Hills Reservoir. Both of these pieces of critical infrastructure adjoin medium to high bushfire hazard land and if compromised would have significant impact on communities in the north of Redland City. The Greater Glider Conservation area between Windemere Road and Vienna Road is marked by a high bushfire hazard, which is bordered by residential properties and Redland Bay Road.

Properties adjacent to bushland areas may be at risk of ember attack should there be a bushfire in the vicinity. During a wildfire, embers can travel up to 3km in front of a fire line which means residents need to be vigilant and be prepared. For more information about bushfire preparedness and what to do during a bushfire, visit the Queensland Fire and Emergency Services website to create your Bushfire Survival Plan – PREPARE.ACT.SURVIVE.

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 City Council works with its Local Disaster Management Group partners to undertake fire mitigation activities around the city.

Flood Prone, Storm Tide

Alexandra Hills has a number of waterways, the majority of which are located within bushland areas. These creeks and waterways do have the potential for flash flooding during heavy rain events. Current flood mapping indicates that residential development in the Alexandra Hills area would experience limited impacts from flash flooding.

Hilliards Creek is also susceptible to flash flooding; the creek rises in the low hills of Sheldon and Thornlands either side of Taylor Road. Woodlands Drive forms part of the catchment boundary between Hilliards and Eprapah Creeks catchments. Hilliards Creek upper branches meet just north of Boundary Road and flows northward, through Alexandra Hills and Ormiston, draining into Central (Moreton) Bay. The creek is about 13km long. The freshwater section of the creek ends at the road crossing at Sturgeon Street Ormiston and the estuarine section extends for three to four kilometres to the foreshore. Wetlands of state significance are located around the mouth of Hilliards Creek and foreshore of Wellington Point.

There is potential for flooding along Tarradarrapin Creek which is flanked by narrow corridors of park or conservation land. The catchment covers the suburb of Birkdale, the edges of Alexandra Hills and Wellington Point. Many stretches of the creek are channelled, including the modified estuaries that are hard lined into Aquatic Paradise and Sovereign Waters. There is a bio-retention basin and swale on a western tributary of Tarradarrapin Creek (between Quarry Rd and Birkdale Rd). This tributary flows into Woodgate Canal of the Aquatic Paradise canal estate, Birkdale. There are closed landfill sites in Birkdale (Judy Holt Park and adjoining property) and Wellington Point (upstream of Sovereign Waters).

Coolnwynpin Creek flows from the edge of Sheldon through parks, residential, urban and commercial areas of Capalaba and Alexandra Hills, and is a major tributary of Tingalpa Creek. Coolnwynpin Creek exits Alexandra Hills at Windemere Road; from Wimborne Road Park and through the Greater Glider Conservation Area. Tingalpa Creek forms the boundary between Brisbane and Redland cities; below Leslie Harrison dam the creek flows past open space, sporting fields and low lying land before flowing into Waterloo Bay.

Landslide

Landslide Hazard mapping indicates that Alexandra Hills has low landslide risk throughout the suburb due to the terrain of the area, with medium risks identified along Hilliards Creek at the boundary with Cleveland, and the Judy Holt Recreation Reserve and Birkdale Waste & Recycling Facility. The areas of low landslide risk are generally identified around the Alexandra Hills Reservoir and the surrounding residential estate east of Vienna Road and continuing further east to Sevenoaks Street and Teesdale Road.

These areas are heavily populated with a high level of 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.

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 effects for mainland communities.

Sewage

The residential areas in Alexandra Hills have been established for many years and are connected to the sewer network which links into the Cleveland Wastewater Treatment Plant, located east of Hanover Drive and west of the Redland Hospital, adjacent to bushland identified as being a medium to high bushfire hazard.

The small number of acreage properties located in the south and north-east of the suburb are not sewered 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

Alexandra Hills receives its water supply from the Alexandra Hills Reservoir located at Alexandra Circuit, Alexandra Hills. The Alexandra Hills Reservoir services the Redland City’s northern suburbs via a pipeline network that is both gravity-fed and pressurised. The reservoir holds a mix of water from the Leslie Harrison Dam and the Herring Lagoon bore field on North Stradbroke Island.

This is possible because the Alexandra Hills Reservoir connects to both the Leslie Harrison Dam and the Mount Cotton Reservoir at Tallow Wood Court, Mount Cotton. This Reservoir is in turn connected to the Heinemann Road Reservoir, Mount Cotton which connects to both the SEQ Water Grid and North Stradbroke Island. Redland City is connected to the Grid via a pump station on Gramzow Road, Mount Cotton which allows water to be pumped to and from the city via the Heinemann Road Reservoir. This network of reservoirs, pump stations and pipelines ensures that water can be moved around the network and that multiple water supplies are available to residents living in all areas Redland City.

Electricity

The main power supply is carried on 110kV overhead powerline network that runs through the acreage areas of Sevenoaks Street and past the Cleveland Wastewater Treatment plant to Cleveland. This network utilises steel towers within a maintained corridor, to mitigate the risks posed by natural disasters such as fire and flood.

There are a few residential pockets at the southern end of Windemere Road and around the Hanover Drive area that utilise an underground powerline network, however the majority of Alexandra Hills has been established for some time and as such is serviced by an overhead powerline network.

Overhead powerlines 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 area surrounding fallen powerlines is more dangerous in wet conditions as sea and tap water are an excellent conductor of electricity.

Energex offer a notification service for Emergency and Planned outages, and other alerts such as upcoming meter read if dogs are onsite or for certain customer service work requests. Click here to go to the Energex Notifications page to Register for this notification service.

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

Alexandra Hills has a pressurised gas main that runs along Finucane Road past the Alexandra Hills Shopping Centre, where it turns south and travels along Sallows Street to McDonald Road, where it turns south to Flinders Street then east to Cleveland behind the Cleveland Cemetery. This gas main is used by commercial enterprises and services the Alexandra Hills Shopping Centre, The Alexandra Hills Hotel and the Retirement Village on McDonald Road.

There is no domestic reticulated gas service within Redland City, however there are 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

Alexandra Hills is connected via landlines to the telecommunications and data networks. There is good mobile network coverage in Alexandra Hills with limited to no mobile reception black spots in the area. Telstra is the major supplier of telecommunications to the region; other suppliers include Optus and Vodafone.

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 Alexandra Hills and there are no plans to extend the rail network to Alexandra Hills in the near future.