Thornlands – Natural hazards and critical infrastructure

Thornlands – Natural hazards and critical infrastructure

Natural Hazards

Bushfire

Thornlands is characterised similarly to other northern coastal suburbs as having scattered high to very high bushfire hazard areas. However, unlike the other coastal suburbs, the majority of the bushfire hazard is located in areas that are currently rural in nature and have not yet seen extensive residential development. As urban development spreads around the Kinross Road estate, residential properties will creep closer and closer to these high to very high bushfire hazard areas.

Properties adjacent bushland areas may be 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 Thornlands Bushfire Prone Map.

Flood Prone, Storm Tide

The Thornlands area has potential to experience flooding as a consequence of either tidal inundation or flash flooding resulting from heavy rainfall events. Thornlands has a number of waterways including the Crystal Waters Dam and Eprapah Creek. Crystal Waters Dam, originally used as a primary water source for the local farm prior to residential development, is centrally located in Thornlands and surrounded by urban development. The dam operates via a spillway that is not gated and empties into Moreton Bay via a creek system that runs through bushland along King Street and Baythorn Drive.

Eprapah Creek is the largest waterway in Thornlands and is impacted by both tidal inundation and flash flooding resulting from heavy rainfall events. The Eprapah Creek system primarily runs through bushland reserve areas, however if the creek floods, current mapping indicates that it will impact the Lakeside Shopping Centre at Victoria Point, the Victoria Point Sewerage Treatment Plant, Faith Lutheran College and other large properties along Beveridge Road and could quite possibly cross Redland Bay Road near the Boundary Road intersection cutting access to Victoria Point.

Current mapping also indicates that low lying areas of Thornlands may experience tidal inundation as a result of a storm tide event. Areas of greatest impact appear to be along shoreline from South Street to King Street. This area of East Thornlands has seen much urban development in recent years which pushes homes closer to the potential tidal inundation areas. What is concerning about these residential developments is that they utilise single road access – one road in, one road out. In East Thornlands, current flood prone, storm tide mapping indicates the possibility of South Street and Thornlands Road being cut by flood water which would effectively isolate a large section of the East Thornlands residential community for a period of time.

Download the Thornlands Flood Prone, Storm Tide Overlay.

Landslide

Landslide Hazard mapping indicates that Thornlands has either no or low landslide risk. The areas of low landslide hazard are generally confined to the acreage areas to the west of the suburb around Woodlands Drive and Taylor road.

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 Thornlands 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.

Sewage

Thornlands has a mix of sewered and non-sewered areas, the residential development areas in the north and east of the suburb are connected to the city’s sewer network. Effluent from these areas is directed to the Alexandra Hills Sewerage Treatment Plant located to the east of Hanover Drive. Current hazard mapping indicates that the Alexandra Hills Sewerage Treatment Plant is surrounded by bushland identified as being a high to very high bushfire hazard.

The rural acreage areas, located in the south and west of the suburb 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

Thornlands receives its water supply from the Heinemann Road Reservoir, located at Mt Cotton. The Heinemann Road Reservoir services the Southern Moreton Bay Islands, Redland Bay, Victoria Point and Thornlands and is 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.

The Heinemann Road Reservoir is also connected to the Herring Lagoon bore field on North Stradbroke Island and the South East Queensland Water Grid via a pump station on Gramzow Road, Mt Cotton. The connection to the South East Queensland Water Grid 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

Thornlands has a mix of both overhead and underground powerline networks servicing the suburb. The more recently developed estates east of Cleveland-Redland Bay Road is primarily where the underground powerline network is located, whilst the remainder of Thornlands which has been the long established is supplied by the overhead powerline network. The 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

There is no domestic reticulated gas service within Redland City. Nor is there a gas main that runs through the suburb of Thornlands. 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

Thornlands is connected via landlines to the telecommunications and data networks. There is good mobile network coverage in Thornlands 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.

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