Alexandra Hills – Natural Hazards and Critical Infrastructure

Alexandra Hills – Natural Hazards and Critical Infrastructure

Natural Hazards

Bushfire

Alexandra Hills is a predominantly a residential area which encompasses large bushland areas to the east and south-west of the suburb. These bushland areas that front McDonald Road and Redland Bay Road and adjoin the rear of properties along Hanover Drive, Nanette Court and Winchester Road are identified as high to very high bushfire hazard. Located in the vicinity of Hanover Drive and Nanette Court is the Alexandra Hills Waste Water Treatment Plant and the Alexandra Hills Reservoir. Both off these pieces of critical infrastructure adjoin high to very high bushfire hazard land and if compromised would have significant impact on communities in the north of Redland City.

Properties adjacent bushland areas may be at risk of ember attack should there be a bushfire in the vicinity. During a wild fire, embers can travel up to 3 kilometres 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 Rural Fire Service website and download the Bushfire Survival Plan – PREPARE.ACT.SURVIVE.

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 Alexandra Hills Bushfire Prone Map.

Flood Prone, Storm Tide

Alexandra Hills has a limited network of waterways, the majority of which are located within the bushland areas with minimal impact on surrounding residential areas. To date, there have been no roads identified in the Alexandra Hills area that are impacted by flooding as a result of heavy rain events.

Download the Alexandra Hills Flood Prone, Storm Tide Overlay.

Landslide

Landslide Hazard mapping indicates that Alexandra Hills has either no or low landslide risk. 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 so 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 Alexandra Hills Flood Prone, Storm Tide 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.

Sewage

Alexandra Hills’ long established residential areas are connected to the sewer network which links into the Alexandra Hills Sewerage Treatment Plant located to the east of Hanover Drive adjacent bushland identified as being a high to very 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.

Water

Alexandra Hills receives its water supply from the Alexandra Hills Reservoir located at Hilltop 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 Mt Cotton Reservoir at Tallow Wood Court, Mt Cotton. The Mt Cotton Reservoir is in turn connected to the Heinemann Road Reservoir, Mt Cotton which connects to both the South East Queensland Grid and North Stradbroke Island. 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 via the Heinemann Road Reservoir, Mt Cotton. 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 to Cleveland, which is carried on 110Kv overhead powerline network, runs through the acreage areas of Sevenoaks Street and past the Alexandra Hills 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 long established 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 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

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 and then east to Cleveland behind the Cleveland Cemetery. This gas main is used by commercial enterprises and services the Alexandra Hills Shopping Centre, The Alex 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 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. The State Emergency Service (SES) have established communications infrastructure on top of the Alexandra Hills Reservoir which provides radio communications capabilities to their emergency service units throughout mainland Redland City.

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