FLOOD INFORMATION FOR TUGGERANONG CREEK OVERVIEW

Tuggeranong Creek is one of eight main water catchments in the ACT. Catchments are areas, usually bounded by hills, where the rain drains into the soil and streams and feeds into a river, creek or drainage line. In Canberra’s past, many natural waterways were converted into the familiar concrete storm drain channels as new areas of the city were developed.

The Tuggeranong Creek catchment is the most southern of Canberra’s catchments, extending from the Monaro Highway, south-east of Theodore, to the Lake Tuggeranong outlet at Athllon Drive. The catchment covers approximately 69 square kilometres and spans approximately 5 kilometres north–south and 13 kilometres east–west.

The catchment is highly urbanised (currently 72%), with some forested areas on the eastern fringes. Residential development began in the early 1970s. Ongoing development, including infill and redevelopment, continues.

This information sheet outlines information about past and potential flooding for the Tuggeranong Creek Catchment and what is being done to mitigate the risk of flooding. The risk of flooding in Canberra is low.

ISABELLA WEIR, GROSS POLLUTANT TRAP

DECEMBER 2018 TUGGERANONG CREEK CATCHMENT NSW

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ISABELLA WEIR TUGGERANONG CREEK CATCHMENT

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TUGGERANONG CREEK CATCHMENT NSW

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D R V E KAMBAH A R I K D E N F O L O L R H T D A Flood maps have been developed for each catchment and reviewed by

D R I V E WANNIASSA independent experts for accuracy. The maps highlight flow paths, flood LAKE TUGGERANONG ACT depth and the potential hazard posed by floodwaters arising from Canberra’s channels, creeks and rivers. This mapping is complemented by this information FADDEN NSW E sheet and a list of questions and answers. The updated maps show the areas V I R D E R I N D A L E which could be affected by flooding from waterways in Canberra during a major OXLEY flood event, known as a 1% Annual Exceedance Probability (AEP) flood. This

GREENWAY means that in any given year there is a 1% chance of this type of flood occurring. V E R I D MONASH A L L E B See the maps and accompanying information at the ACT Government’s A I S ACTmapi website: www.actmapi.act.gov.au. TUGGERANONG CREEK CATCHMENT FLOOD HISTORY RICHARDSON The Tuggeranong Creek catchment is not prone to frequent and extensive flooding. It has experienced minor flooding, including in 2014, caused by heavy rainfall centred around Mount Taylor.

CALWELL In the Tuggeranong Creek system, flooding is characterised by fast flowing M O N A flood water in and around the extensive creek channel network and culverts. R ACT O MURRUMBIDGEE RIVER FLOWING INTO LAKE TUGGERANONG H

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A Y FLOOD MAPS AND AFFECTED AREAS The new flood maps specifically focus on a potential 1% AEP flood on existing waterways. As explained, there is a 1% chance that such a flood will occur in any given year. The maps show the predicted path, depth and hazard potential of a 1% AEP flood event. They show that the channels, culverts and bridges in the Tuggeranong Creek catchment will generally contain a 1% AEP event, with water flowing at high speeds making it hazardous in places. If flooding does occur outside the channels, flood depths are generally expected to be shallow .

For the 1% AEP flood event, there is the potential of extensive low level flooding in the Isabella Plains and in some sections of Kambah, Wanniassa, Greenway and Monash.

Please refer to the flood extent map for Tuggeranong Creek on ACTmapi for the specific details of potential riverine flooding in this catchment.

TUGGERANONG CREEK CATCHMENT TUGGERANONG LAKE

MITIGATION WORKS FIND OUT Tuggeranong Weir was built in the early 1970s and Lake Tuggeranong, Isabella Weir and Upper Stranger Pond in 1988. They were primarily built to protect the water MORE quality downstream in the Murrumbidgee River and Murray–Darling River Basin. →→ For flood maps for this Due to the urban nature of the catchment, the Tuggeranong Creek system is catchment please visit crossed by major arterial roads. The embankments at these crossings create www.actmapi.act.gov.au. artificial flood storages, which during a flood would provide some help in →→ For more information about managing the peak flows to areas lower in the catchment. However, this also riverine flooding in Canberra, means that the areas above these embankments would be at increased risk of please visit http://www. flooding during a major flood event. environment.act.gov.au/water/ riverine-flood-maps Under the Territory Plan, the Water Sensitive Urban Design (WSUD) code outlines planning rules for reducing the impact of stormwater through the →→ For information including flood management of water quality and quantity . The rules are designed so that forecasts, road closures and run-off created by new development does not have an adverse impact on advice on evacuation and property stormwater systems or downstream environments. protection, please visit the ACT Emergency Services website at As a result of developing the above mentioned 1% AEP maps the ACT www.esa.act.gov.au. Government has identified the key flood risk areas that require further →→ For specific information relating to investigation. Work has begun in these areas to refine the existing models what to do during a flood event or and check whether buildings will be impacted in potentially affected areas. preparing your house for a flood Options for built infrastructure to help prevent and contain floods are also event please call the local being investigated; impacted stakeholders will be advised of the outcome ACT SES on 13 22 81. of these studies as they become available.

TUGGERANONG CREEK CATCHMENT