Birkdale – Natural Hazards and Critical Infrastructure

Birkdale – Natural Hazards and Critical Infrastructure

Natural Hazards

Bushfire

Current mapping suggests that Birkdale has a number of areas of bushfire hazard ranging from moderate to very high bushfire hazard. The very high bushfire hazard has been identified primarily on land adjacent the residential areas along Sunnybay Drive and surrounding the Birkdale Landfill and Judy Holt Sports Field. These areas bushland areas have thick vegetation up to property boundaries and along road reserves. There is also a large area of moderate bushfire hazard fronting the south-eastern boundary of the Birkdale Golf Club, however there is limited residential development n this area.

Properties that are adjacent to 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 Birkdale Bushfire Prone Map.

Flood Prone, Storm Tide

Current mapping shows that parts of Birkdale will experience impacts from flooding due to having areas bordering both the Tingalpa Creek and the coastline as well as having areas of overland flow running throughout the suburb. Coastal areas near Aquatic Paradise may experience tidal inundation during a storm tide event. At highest risk are properties around Queens Esplanade and Agnes Street to the West of Aquatic Paradise and to the east, tidal inundation may push as far inland as Birkdale Road, impacting properties along Bath Street, Thomas Street, Cavell Street and Murray Street.

Potential flooding along Tingalpa Creek in Birkdale as a consequence of storm tide appears to have limited affects on properties adjacent the creek apart from the Birkdale Golf Club which would see its fairways heavily impacted. Also impacting the Golf Club fairways and surrounding acreage and bushland areas is overland flow resulting from heavy rainfall events. Current mapping indicates that this type of flooding may impact a small number of homes and businesses along Birkdale Road and Collingwood Road.

The potential for flooding along Tingalpa Creek is heightened during heavy rain events that cause releases to occur from the Leslie Harrison Dam which is situated approximately 6.5 kilometers inland from the mouth of the creek. Dam managers closely monitor the water levels in the dam and ensure that dam releases do not coincide with storm tide events that would push water back up Tingalpa Creek.

To reduce the potential impacts of releases from the Leslie Harrison Dam, Redland City Council in partnership with SEQ Water has devised a strategy of trickle flow releases to coincide with tide times prior to the dam reaching maximum capacity. SEQ Water has developed a comprehensive Emergency Action Plan for the Leslie Harrison Dam to meet the requirements of the Water Supply (Safety and Reliability) Act 2008 in order to manage any crisis or dam failure.

Download the Birkdale Flood Prone, Storm Tide Overlay

Landslide

Landslide Hazard mapping indicates that Birkdale’s residential area has a very limited risk of landslide, with only a few properties showing a low landslide hazard. The Birkdale Landfill and the Judy Holt Sports Field adjoining Old Cleveland Road East have been identified as being a medium landslide hazard.

Any structures built in this area would need to comply with the requirements of the Redland Planning Scheme which, 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 Birkdale 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

Birkdale’s residential areas are connected to the sewer network which links into the Thorneside Sewerage Treatment Plant located off Quarry Road. Current hazard mapping indicates that the Thorneside Sewerage Treatment Plant may experience impacts from tidal inundation during an extreme storm tide event.

Birkdale has a small number of acreage properties located to the west of Birkdale Road that 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

Birkdale 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

Birkdale has even mix of both overhead and underground powerline networks servicing the suburb. This mix is due to the established farming and acreage areas of Birkdale being more recently sub-divided for urban development. 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 Birkdale. 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

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

Harbours and Marinas

Situated within Birkdale is the canal estate of Aquatic Paradise. Aquatic Paradise is a relatively small canal estate that does not have a central marina area. Canal traffic and infrastructure is confined to the homes that front the canal. Whilst current mapping indicates limited impacts from storm surge, residents should be prepared for the possibility of their homes experiencing tidal inundation during an extreme storm tide 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

The rail network enters Redland City via Thorneside, crossing the Tingalpa Creek to the north of the Thorneside sewerage treatment plant and continues on to the Thorneside Station. From Thorneside Station the rail network continues east to Birkdale Station and Wellington Point Station where the line turns south-east to Ormiston Station and Cleveland Station where it terminates.

Current Flood Prone, Storm Tide mapping indicates the possibility of the rail network being cut by flood water on the Redland City side of Tingalpa Creek, north of the Tingalpa Station. If this were to occur, rail transport in and out of Redland City would be cut along with rail access to Brisbane City. This would prevent any evacuations via rail to the RNA Showgrounds which is the primary evacuation centre for Brisbane and an alternate evacuation centre for Redland City residents should the city’s infrastructure be significantly compromised by a disaster event.