FLOOD INFORMATION FOR CREEK OVERVIEW

Ginninderra 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 , creek or drainage line. In ’s past, many natural waterways were converted into the familiar concrete storm drain channels as new areas of the city were developed.

The catchment is in north-west Canberra. Over 35% of ACT residents live in the catchment, making it the most urbanised catchment in the ACT. Ginninderra Creek rises in the upper reaches of and enters the Murrumbidgee at Ginninderra Gorge, below the falls. Ginninderra Creek mostly follows its natural channel, with some short sections converted to concrete stormwater drains.

The catchment covers approximately 320 square kilometres and spans approximately 18 kilometres north–south and 18 kilometres east–west. It has urban and rural residential land uses, broadacre farming and nature reserves. Urban development in the catchment, which has occurred rapidly since preliminary development began in the mid-1960s, includes the new suburbs being developed in West , downstream from .

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

GIRALANG AND POND IN FLOOD DECEMBER 2018 GINNINDERRA CREEK CATCHMENT FLOOD INFORMATION

NSW

BONNER

BONNER POND

HALL HORSE PARK POND FORDE

CASEY

G U NGUNNAWAL YERRABI POND N G A H L E I N I V GOOROOYARROO POND D R R D I V E O O A R NICHOLLS N D GUNGAHLIN G U FRASER

GINNINDERRA CREEK PALMERSTON CATCHMENT GUNGAHLIN POND B A R T O N H MACGREGOR EVATT I G H W A Y A Y H W I G H L A R E D E WILLIAM SLIM F RETARDING BASIN LATHAM LAKE GINNINDERRA POND

LATHAM BASINS LAWSON

Y FLOREY W A LAKE GINNINDERRA DAM G H H I L R A D E F E B G UC A I R N T N I O N D E LAKE GINNINDERRA R R N A D H R I I G V E H W A BELCONNEN Y

E V I R

D

N

HAWKER I

L B E H HAWKER OVAL L C A O G N N N RETARDING BASINS E N AIS U W G A Y

MACQUARIE

E

U

N

E

V

A Y

A

E

W N

K R

R

U

A

O

P

B A

H

R T D

R U

A

J

O

O

A

N R

M

A

R U

J

A

H O V E M I A M L D W I L L R I V E

GINNINDERRA CREEK CATCHMENT

D A O R

G

N

I C O S N

S S T O E I T U R P U A T C N R I K O E S E N V S N A I A W V P A E Y N P H U E O T

C L

A

E

W Y A N W O

K M R A M D P O A G C N O R O N A N R O

E T

G T G U U S T

J U E O E N A V H I D E L A E N D E A U

G N O E V R A

D C E O A N N N R

D U B R O E I B R V L R A A V E E N O A V E N U E M E U E P I A L L I G

N

E

L

G

A

R

R

A

Y C A N M B E U R

E R G A

V

G A I V

A E R N

U

D W E

N A

O Y T J E E E R R R

T A

S B O M B E R R H A I N D M A M V A R S E E H D L N R I V R U E O E S

Y E

C A

A D

W H I N D M A R S N

R H D K R B I I V V E R E R E R A A

P

A V

G E N N U O E

N

A

R

E

G W

G A

U M T B A

D R I V

E

E

V

I

R

D

N

Y

O

A

L

L

W

H

H

T

G

I

A

H

O

R

A

N

O

M E R I V O N D

Y

N A

S L

U

L

W

O

O

D

D R I V E

D R V E A R I K D E N F O L O L R H T D A

D R I V E ACT NSW E V I R D E R I N D A L E

V E R I D A L L E B A I S

M O N A R ACT O

H

I

G

H W NSW

A Y FLOOD INFORMATION

Every catchment has its own character, which determines how water flows. This is critical during storms that may lead to NSW flooding. The ACT Government has re-assessed predicted flood paths and flood levels for catchments in the ACT using flood studies based on current industry standards.

Flood maps have been developed for each catchment and reviewed by BONNER independent experts for accuracy. The maps highlight flow paths, flood depth and the potential hazard posed by floodwaters arising from Canberra’s

HALL FORDE channels, creeks and . This mapping is complemented by this information sheet and a list of questions and answers web link. The updated CASEY maps show the areas which could be affected by flooding from waterways in Canberra during a major flood event, known as a 1% Annual Exceedance

G Probability (AEP) flood. This means that in any given year there is a 1% chance U NGUNNAWAL N G A H of this type of flood occurring. L E I N I V D R R D I V E O O A R NICHOLLS N D GUNGAHLIN See the maps and accompanying information at the ACT Government’s G U FRASER ACTmapi website: www.actmapi.act.gov.au. GINNINDERRA CREEK

GINNINDERRA CREEK PALMERSTON FLOOD HISTORY CATCHMENT B The Ginninderra Creek catchment has not experienced a 1% AEP flood since A R T O N records have been kept. Minor flood events over the last ten years occurred H MACGREGOR EVATT I G H W A in 2005, 2007 and 2012. A combination of catchment topography and a large Y A Y H W I G H L catchment and water storages (dams) means that flood waters can generally be A R E D E contained and most of the creek is not prone to significant flooding . F

LATHAM The Yerrabi, Gungahlin and Ginninderra ponds within the catchment need long periods of rain before overflowing and flooding. This creates sufficient warning

LAWSON time, often more than eight hours, between the onset of rainfall and the arrival of the flood peak. Y FLOREY W A G H H I L R A D E F E B G UC A I R N T N I O FLOOD MAPS AND AFFECTED AREAS N D E LAKE GINNINDERRA R R N A D H R I I G V E H W A The new flood maps specifically focus on a potential 1% AEP flood on existing BELCONNEN Y waterways. As explained, there is a 1% chance that such a flood will occur in

E V any given year. The maps show the predicted path, depth and hazard potential I R

D

N

HAWKER I of a 1% AEP flood event. During a 1% AEP flood, water levels in the Ginninderra

L B E H L C A O G Creek channels and floodways may be deep in some places and characterised N N N E N AIS U W G A Y by fast flows, creating hazardous conditions.

MACQUARIE The maps show that the channel and floodway will generally cope with a 1% E

U

N

E AEP flood except for some specific locations. There is the potential for low level V

A Y

A

E

W N flooding (less than 0.5 metre) in sections of Latham and MacGregor and higher

K R

R

U

A

O

P

levels (greater than 0.5 metre) in some areas of McKellar .

B A

H

R T D

R U

A

J

O

O

A

N R

M Please refer to the flood extent map for Ginninderra Creek on ACTmapi for the

A

R U

J specific details of potential waterway flooding in this catchment.

A

H O V E M I A M L D W I L L R I V E

GINNINDERRA CREEK CATCHMENT

D A O R

G

N

I C O S N

S S T O E I T U R P U A T C N R I K O E S E N V S N A I A W V P A E Y N P H U E O T

C L

A

E

W Y A N W O

K M R A M D P O A G C N O R O N A N R O

E T

G T G U U S T

J U E O E N A V H I D E L A E N D E A U

G N O E V R A

D C E O A N N N R

D U B R O E I B R V L R A A V E E N O A V E N U E M E U E P I A L L I G

N

E

L

G

A

R

R

A

Y C A N M B E U R

E R G A

V

G A I V

A E R N

U

D W E

N A

O Y T J E E E R R R

T A

S B O M B E R R H A I N D M A M V A R S E E H D L N R I V R U E O E S

Y E

C A

A D

W H I N D M A R S N

R H D K R B I I V V E R E R E R A A

P

A V

G E N N U O E

N

A

R

E

G W

G A

U M T B A

D R I V

E

E

V

I

R

D

N

Y

O

A

L

L

W

H

H

T

G

I

A

H

O

R

A

N

O

M E R I V O N D

Y

N A

S L

U

L

W

O

O

D

D R I V E

D R V E A R I K D E N F O L O L R H T D A

D R I V E ACT NSW E V I R D E R I N D A L E

V E R I D A L L E B A I S

M O N A R ACT O

H

I

G

H W NSW

A Y MITIGATION WORKS FIND OUT Ginninderra Creek was planned differently to Sullivan’s, Yarralumla and creeks. The main watercourse was left in a largely natural state, MORE green space was provided around the watercourses, and ponds were built for →→ For flood maps for this catchment water quality and flow retardation. The three ponds (Yerrabi, Gungahlin and please visit www.actmapi.act.gov.au Ginninderra) were constructed on Ginninderra Creek to capture and treat run- off from urban development in the catchment. During heavy rain, these ponds →→ For more information about are critical in reducing the peak water flows caused by urbanisation; run-off is riverine flooding in Canberra, higher in urban areas where rain runs off all the impervious surfaces such as please visit http://www. roads and roofs. environment.act.gov.au/water/ riverine-flood-maps Under the Territory Plan, the Water Sensitive Urban Design (WSUD) code outlines →→ For information including planning rules for reducing the effects of stormwater through the management flood forecasts, road closures of water quality and quantity as close to the source of impact as possible. and advice on evacuation and The rules are designed so that run-off created by new development does not property protection, please visit have an adverse impact on stormwater systems or downstream environments. the ACT Emergency Services website at www.esa.act.gov.au. As a result of developing the above mentioned 1% AEP maps →→ For specific information relating to the ACT Government has identified the key flood risk areas that what to do during a flood event or require further investigation. Work has begun in these areas preparing your house for a flood to refine the existing models and check whether buildings event please call the local will be impacted in potentially affected areas. Options for built ACT SES on 13 22 81. infrastructure to help prevent and contain floods are also being investigated; impacted stakeholders will be advised of the outcome of these studies as they become available.

LAKE GINNINDERRA WETLAND

GINNINDERRA CREEK CATCHMENT