Stonnington Flood Management Plan - Grace's revised version October 2013

Flood Management Plan
For City of Stonnington and Melbourne Water
April 2013

Table of contents
Stonnington Flood Management Plan Melbourne Water i
List of Figures ii
List of Photos ii
Approval iii
Executive Summary iv
1. Introduction 1
2. Background 1
3. Purpose 2
4. Objectives 2
5. Scope 3
6. Stonnington’s Waterways and Drainage System 3
6.1. The City of Stonnington 3
6.2. Waterways in Stonnington 5
6.3. The Drainage System 7
6.4. Flood History and Issues 11
6.5. Flood Data, Information and Intelligence 15
7. Flood Risk 15
7.1. Flood Risk Assessment 16
7.2. Existing Flood Risks within the Municipality 17
7.3. Future Flood Risks 22
8. Flood Management and Mitigation 23
8.1. Drainage Strategy 23
8.2. Flood Modelling and Mapping 24
8.3. Asset Management 26
8.4. Planning Controls 28
8.5. Capital Works 32
8.6. Flood Emergency Planning 34
8.7. Community Education and Awareness 35
8.8. Flood Warning Systems 37
8.9. Drainage studies and guidelines 39
9. Roles and Responsibilities 40
10. Communication 41
11. Improvement Plan 42
12. Monitoring and Review 59
13. How this document was developed 60
14. Acknowledgements 60
Abbreviations and Acronyms 61
Glossary 62
References 63
Appendix A – Asset List 64
Appendix B – Roles and Responsibilities 65

Table of contents continued
ii Melbourne Water Stonnington Flood Management Plan
Appendix C – Flood Risk Assessment 68
Appendix D – Workshop attendees 70
List of Figures
Figure 1: Stonnington Municipality and Suburbs 4
Figure 2: Melbourne Water Main Drains, Waterways and 6
Ancillary Drainage Infrastructure
Figure 3: Melbourne Water and City of Stonnington Drains 8
Figure 4: Melbourne Water Defined Drainage Catchments 9
Figure 4a: Council Defined Drainage Catchments 10
Figure 5: Historical Recorded Flood Locations 14
Figure 6: Melbourne Water Catchment Risk Rating and 18
City of Stonnington Identified Hot Spots
Figure 7: Properties Waterways Identified as Flood-Prone 20
Figure 8: Safety Risk in Roads 21
Figure 9: Melbourne Water and City of Stonnington Flood Extents 25
for 20yr, 50yr and 100yr Events
Figure 10: Drains, Waterways and 100yr Flood Extents 27
Figure 11: Flood Overlays 30
Figure 12: Key Services and Vulnerable Locations 36
List of Photos
Photo 1: Flooding in Prahran 3
Photo 2: Gardiners Creek in flood 11
Photo 3: Flooding on Toorak Road 17
Photo 4: Tree leaves and drain 28
Photo 5: New drainage pits, South Yarra 34

Stonnington Flood Management Plan Melbourne Water iii
Approval
This Plan has been developed in consultation with the City of Stonnington,
Melbourne Water and Victoria State Emergency Service. The Plan will continually
evolve as improved information becomes available to help manage flood risks
across the Stonnington municipality.
As lead stakeholders for managing flood risks across the region,
Melbourne Water and the City of Stonnington will endeavour to implement the
recommendations made in this plan and also to review and update it as required
on an annual basis.
Approved by Signature Date
Phillip Neville
Manager Floodplain Services
Melbourne Water
Rick Kwasek
Manager Public Spaces and
Capital Works
City of Stonnington

iv Melbourne Water Stonnington Flood Management Plan
Executive Summary
This Stonnington Flood Management Plan (this Plan) outlines roles and
responsibilities and describes, at a high level, City of Stonnington and
Melbourne Water’s key flood planning and management activities. This Plan
identifies a series of specific actions to improve flood management in the City of
Stonnington over the next five years. This Plan has been jointly developed by
the City of Stonnington and Melbourne Water to implement the objectives of the
Port Phillip and Westernport Region Flood Management and Drainage Strategy
(Melbourne Water, 2007a).
Flood risk in Stonnington
Melbourne Water has identified five extreme risk catchments within the
Stonnington municipality: the Murrumbeena Main Drain; Scotchmans Creek;
Chadstone Main Drain; Prahran Main Drain; and Tooronga Road Main Drain;
within which there are 4,859 residential and commercial/industrial properties at
risk of flooding. The City of Stonnington has also identified 5,322 properties as
being subject to flooding for a storm with an Average Recurrence Interval (ARI)
of 1 in 100 years (4,945 properties in the Special Building Overlay (SBO) and
377 properties to be included with future Council SBO revisions). In total, there
are approximately 10,500 properties at risk of flooding in Stonnington.
Agreed Responsibilities and Collaboration
City of Stonnington, Melbourne Water, Victoria State Emergency Service
(VICSES) and other agencies have important roles and responsibilities relating
to drainage and flood management. Melbourne Water will provide Council with
technical and financial assistance to ensure an ongoing partnership approach to
the further development and implementation of this Plan. The City of
Stonnington will seek a collaborative approach in facilitating the delivery of any
prioritised works and activities.
Key Improvement Plan Actions
The Stonnington Flood Management Plan identifies a series of actions to reduce
flood risk. Key actions (numbered in accordance with the Improvement Plan)
are:
 St-1: City of Stonnington to update the Council SBO to incorporate revised
flood extents (to be reported to Council by December 2016);
 St-3: Melbourne Water to review the naming convention of the SBO to
enhance clarity and community understanding (by December 2014);
 St-9: Melbourne Water and City of Stonnington (along with other
organisations) to consider if an integrated flood study is required of the
Union Street Main Drain catchment, Prahran (by December 2013);
 St-10: City of Stonnington to review its maintenance and operations plan for
drainage assets (by December 2013);

Stonnington Flood Management Plan Melbourne Water v
 St-12 and St-14: VICSES and City of Stonnington to prepare a
Flood Emergency Plan and develop a community flood education program
(to be completed in several stages by June 2013 and then ongoing); and
 St-15: City of Stonnington to further investigate options for providing general
information on storm warning systems so that occupants and property
owners of buildings prone to localised flooding can take appropriate action
(by December 2014).
This Plan was developed by a wide range of City of Stonnington and
Melbourne Water staff with input from other agencies, particularly VICSES. The
development of the Plan included data gathering, GIS mapping, meetings, site
visits and workshops to gather the background information, identify flood risk
management and mitigation activities, undertake a gap analysis and develop an
improvement plan.
Melbourne Water will be responsible for initiating annual review and updates of
this Flood Management Plan with the City of Stonnington. Melbourne Water and
City of Stonnington will track and report to each other on actions in the
Improvement Plan on an annual basis. The Plan will be revised at least every
five years to reflect achievement of objectives and changes to work program
priorities.

Stonnington Flood Management Plan Melbourne Water 1
1.Introduction
This document is the Flood Management Plan for the City of Stonnington and
Melbourne Water. It has been developed in response to an identified need to
improve collaboration between flood management agencies and for City of
Stonnington and Melbourne Water to work at a local level to implement the
objectives of the Port Phillip and Westernport Region Flood Management and
Drainage Strategy (Melbourne Water, 2007a).
The Flood Management Plan outlines roles and responsibilities and describes
City of Stonnington’s and Melbourne Water’s key flood planning and flood
management activities. It details the flood risks for the municipality, particularly
identifying any hot spot or problem areas, and also contains an improvement
plan detailing the actions required to address any key gaps identified in
developing the Plan.
2.Background
The Port Phillip and Westernport Region Flood Management and Drainage
Strategy (Melbourne Water, 2007a), prepared by Melbourne Water in
consultation with government departments, councils, emergency service
organisations and other agencies, recognises that no single organisation and no
single approach can deliver an effective response to flood management issues.
A coordinated and collaborative approach by flood managers and communities is
required.
The five key objectives of the Strategy are:
Objective 1: Completing the knowledge base (through flood mapping and
understanding social impacts).
Objective 2: Identifying potential long-term future pressures on existing
drainage systems (such as development in established areas and
climate change).
Objective 3: Determining an agreed approach to managing existing regional
flood problems (understanding intolerable flood risks).
Objective 4: Enhancing community education, flood awareness and
preparation.
Objective 5: Agreeing on responsibilities and improving collaboration between
flood management agencies (through implementation of an
integrated framework and flood management plans).
One of the key outcomes from the strategy was the commitment from
Melbourne Water to work with each municipality within the region to produce a
detailed local Flood Management Plan. This document is the result of delivery on
that commitment for the City of Stonnington.

2 Melbourne Water Stonnington Flood Management Plan
3.Purpose
This Plan is aimed at assisting the City of Stonnington and Melbourne Water to
undertake their flood management responsibilities and ensure that suitable
measures have been (or are being) implemented where possible to manage the
existing risks associated with flooding. It is aimed at ensuring the objectives of
the Port Phillip and Westernport Region Flood Management and Drainage
Strategy can be implemented in the Stonnington municipality in a coordinated
and effective manner at a local level, within an integrated flood management
framework. It is also aimed at fostering preparedness for flood events and an
ability to respond in an informed and appropriate manner within the City of
Stonnington and its communities.
While the Plan has due regard for current flood related legislation and
supporting policies and strategies, it recognises that no single organisation and
no single approach can deliver an effective response to flood management
issues. It also recognises that it is not possible to eliminate areas subject to
flooding within the Stonnington municipality; a residual risk will remain.
This Flood Management Plan has been prepared in conjunction with
Melbourne Water as part of a joint focus on managing existing, residual and
future flood risks within the City of Stonnington. The genesis for that focus is
provided in the Port Phillip and Westernport Region Flood Management and
Drainage Strategy.
4.Objectives
The objectives in developing and maintaining this Flood Management Plan for
the Stonnington municipality are to:
 Facilitate coordination and cooperation in the implementation of the five key
strategies outlined in the Port Phillip and Westernport Region Flood
Management and Drainage Strategy with particular attention to existing flood
risks;
 Promote improved collaboration between the City of Stonnington,
Melbourne Water and the Victoria State Emergency Service (VICSES);
 Understand flood risks and identify the range of low, medium, high and
extreme (or intolerable) flood risks and hot spot areas in the
Stonnington municipality;
 Identify gaps and improvement actions that are needed to address these
risks and better prepare for and manage floods;
 Ensure that drainage and flood management matters within Stonnington are
effectively managed and coordinated through flood management agency
collaboration and partnership between City of Stonnington, Melbourne Water
and VICSES; and
 Clarify the roles and responsibilities of stakeholders in addressing existing
flood risks.

5.Scope
While management of and preparedness for floods arising from waterways and
drainage systems involves many different agencies, this Plan is largely aimed at
outlining the key activities, roles and responsibilities for Melbourne Water and
the City of Stonnington within a total system framework that recognises their
joint responsibility for the management and ownership of the drainage system.
Emergency response planning does not form part of this plan and will be the
subject of a Flood Emergency Plan which will be prepared separately by VICSES
and City of Stonnington (see Improvement Plan Action St-12).
6. Stonnington’s Waterways and Drainage
System
6.1. The City of Stonnington
The City of Stonnington is located in Melbourne’s inner south-eastern suburbs
covering an area of 25.62 square kilometres. The City of Stonnington consists of
the suburbs of Prahran, Windsor (part), South Yarra (part), Toorak, Armadale,
Malvern, Malvern East, Kooyong and Glen Iris (part) (City of Stonnington,
2011a).
The Yarra River and Gardiners Creek form the northern boundary of the
municipality and the City of Stonnington shares this boundary with the Cities of
Yarra and Boroondara; Punt Road is the western boundary with the City of
Melbourne; Warrigal Road forms the eastern boundary with the City of Monash;
and Dandenong Road and Princes Highway/Queens Way form the southern
boundary with the Cities of Port Phillip and Glen Eira (see Figure 1).
Photo 1: Flooding in Prahran

In 2012, the City of Stonnington had an estimated population of 101,489.
By 2031, the municipality is forecast to grow to 117,779 with a population
growth rate of approximately 0.86 percent per year. In 2012 there were an
estimated 46,496 households with over 30 percent of these as single person
households (forecast.id®
, 2012).
Stonnington has a relatively young population with 50 percent of the population
younger than 35 years, and 30 percent of the population aged 20 to 34 years.
Nineteen percent of the community were born in non-English speaking countries,
with the top five non-English languages being Greek, Chinese, Italian, Russian
and Indonesian. The three most common occupational categories in Stonnington
are professionals, managers and administrative workers. Around 22 percent of
Stonnington workers are employed within the municipality (City of Stonnington,
2011a).
The City is primarily a residential area, with some commercial, industrial and
institutional land uses. Stonnington has significant commercial centres along
Chapel Street, Toorak Road, High Street, Glenferrie Road and at the Chadstone
Shopping Centre in East Malvern. Stonnington has a variety of parks, gardens
and open space including Victoria Gardens, Central Park and the Glen Iris
Wetlands. Recreation facilities include the Malvern Valley Golf Club, two aquatic
centres, sports grounds, tennis centres and bicycle paths.
Stonnington has a range of business sectors with the largest being property and
business services, retail trade, construction, manufacturing, finance and
insurance, health and community services, cultural and recreational services,
accommodation, cafes and restaurants (City of Stonnington, 2010). Stonnington
has major transport networks passing through the municipality including primary
and secondary arterial roads, and railway lines.
6.2. Waterways in Stonnington
The City of Stonnington has three major waterways: Yarra River;
Gardiners Creek; and Scotchmans Creek. Gardiners Creek and Scotchmans Creek
flow into the Yarra River which enters Port Phillip Bay at Port Melbourne
(see Figure 2). Ancillary drainage infrastructure including Melbourne Water’s
stream gauges and a water quality monitoring site are also shown in Figure 2.
Stonnington’s waterways are impacted by water pollution and degradation from:
channelling and erosion from inappropriate land and water management; erosion
caused by loss of vegetation along creek banks; and pollution from urban run-
off. Sections of Gardiners Creek and the Yarra River that lie within Stonnington
are largely bordered by open space, and the level of remnant and Indigenous
vegetation is generally poor (City of Stonnington and Melbourne Water, 2010).

6.3. The Drainage System
Melbourne Water is responsible for the installation and maintenance of its
main drains, including drain capacity and flood mitigation works, and for
managing Melbourne’s waterways. Generally, Melbourne Water is responsible for
catchments above 60ha.
Within the Stonnington municipality, stormwater is collected by a network of
drains and channels and diverted to main drains and then waterways to make its
way to Port Philip Bay. Figure 3 shows Melbourne Water and City of Stonnington
main drains and local drains. Figure 4 shows the Melbourne Water defined
drainage catchments and Figure 4a shows the Council defined drainage
catchments.
City of Stonnington is responsible for the network of drains and channels (other
than the main drains) throughout the municipality. This network of
underground pipes, open drains, culverts and channels incorporated with street
paving (kerb and channel) provides an industry standard level of drainage
protection for properties, footpaths and roads. City of Stonnington is responsible
for maintenance of the local drainage system, assessment of land-use and
development applications, administration and enforcement of local laws and
emergency management. All properties are required to have a (private)
stormwater drainage system that effectively collects and discharges the
stormwater runoff from that property into the drainage network.
The City of Stonnington has an estimated 315km of drains and there are
approximately 13,654 drainage pits.1
Within the City of Stonnington, new drainage in known areas of flooding is
designed, where possible, for a 1 in 20 year level of protection; however,
drainage options and capacity are at times limited. There is limited ability to use
retarding basins in the Stonnington municipality given extensive urban
development and high land value for residential and commercial development.
Older parts of the underground drainage
system were generally designed to accommodate a 1 in 5 year
Average Recurrence Interval (ARI) storm for the existing building development at
that time. New development may result in a reduction in this design standard.
Council has a policy of upgrading drains in these areas from a 1 in 5 year to a
1 in 10 year ARI storm based on the anticipated future development.
The length, diameter and location of City of Stonnington’s drains and associated
infrastructure are stored in the Council’s Geographic Information System (GIS).
This information has been compiled from detailed construction plans and
drainage maps, and from site inspections which have then been accurately
recorded on base plans.
1
City of Stonnington 2010, Drainage Asset Valuation Summary as at June 2010.

There are also some drains, associated with major roads, owned and maintained
by VicRoads within the Stonnington municipality. Examples of freeways and
highways in the municipality include the South Eastern (Monash) Freeway,
Princes Highway and Dandenong Road. There are also some VicTrack drains
associated with railways.
6.4. Flood History and Issues
Historically, the Stonnington municipality was significantly impacted by flooding
from the Yarra River. In the Great Flood of 1891, for example, the Yarra River
rose 14 metres above its normal level in some areas. It flooded many riverside
suburbs including Prahran and caused extensive damage. There was also
extensive flooding along the Yarra River in 1934. Since the 1891 flood, extensive
remedial work has been carried out on the lower Yarra River, including widening
and redirecting its course to Port Phillip Bay. As a result, the impact of riverine
flooding on the community has now been substantially reduced
(Melbourne Water, 2007a).
The Stonnington municipality is impacted by localised flooding from major storm
events; for example, over the last 20 years Melbourne Water has recorded major
storm events and flooding in the following Stonnington catchments
(Melbourne Water, 2012a):
 Gardiners Creek catchment: 3 December 2003; 29 January 2004;
3 February 2005; 25 February 2006; and 20 December 2007;
 Murrumbeena Main Drain catchment: 1 January 1996; 30 January 2004; and
4 February 2011;
 Scotchmans Creek catchment: 3 December 2003; 3 February 2005;
20 December 2007; and 5 February 2011; and
 Tooronga Road Main Drain catchment: 3 December 2003; 29 January 2004;
3 February 2005; 25 February 2006; 20 December 2007; and
4 February 2011.
Photo 2: Gardiners
Creek in flood

Storm events and descriptions as identified by City of Stonnington are outlined in
Table 6.1.
Table 6.1: Storm Events and Descriptions, City of Stonnington
Date Rainfall Intensity Comments
24 and 28
March 1974
1 in 25 and 1 in
100 year ARI
The storms occurred one week apart with
the same properties being flooded twice.
This resulted in future drainage works
being carried out to a higher design
standard, particularly in areas subject to
flooding.
14 December
1993
1 in 60 year ARI Critical storm duration 18 minutes
27 December
1999
Greater than 1 in
100 year ARI
Critical storm duration 30 minutes to
1 hour. Flooding mainly in Windsor,
Prahran and South Yarra areas.
29-30
January 2004
Greater than 1 in
100 year ARI
1 hour. Flooding mainly along the southern
part of the municipality.
25 January
2006
1 in 67 year ARI Critical storm duration 1 hour to 2 hours.
20/21
December
2007
1 in 50 year ARI Critical storm duration 12 minutes to
30 minutes. Flooding mainly in the
southern and eastern part of the
municipality.
6 March 2010 1 in 55 year ARI Critical storm duration 12 minutes to
30 minutes. Flooding mainly in the
South Yarra, Toorak and Malvern areas.
4 February
2011
Greater than 1 in
100 year ARI and
estimated to be
greater than 1 in
200 year ARI
24 hours. All areas of municipality affected.
The last major flooding within the Stonnington municipality was in February 2011
when large areas across the municipality were affected. The storm caused
significant basement flooding with some evacuations of residential and
commercial property. It also affected public areas and infrastructure (City of
Stonnington, 2011b).
Table 6.2 shows flood class levels for Gardiners Creek at Gardiner
(Melbourne Water, 2012b).
Table 6.2: Flood Class Levels for Gardiners Creek at Gardiner
Minor Moderate Major
Flood Class Level (m) 3.4 4.4 4.8

Table 6.3 shows flood events since 1978 that exceeded flood class levels for
Gardiners Creek at Gardiner (Melbourne Water, 2012b). There was a major flood
event in February 2011, and four moderate events in December 1978,
September 1984, November 1988 and February 2006.
Table 6.3: List of Floods Exceeding Flood Class Levels for Gardiners
Creek at Gardiner
Date and Time Peak Level (m) Flood Class
25/12/1978
Time: 19:54
4.76 Moderate
6/10/1979
Time: 5:00
3.41 Minor
25/05/1981
Time: 16:30
3.40 Minor
18/09/1984
Time: 19:36
4.77 Moderate
22/11/1988
Time: 9:12
4.42 Moderate
22/03/1991
Time: 8:06
3.80 Minor
27/12/1993
Time: 15:00
3.96 Minor
8/03/1995
Time: 6:12
3.48 Minor
3/02/2005
Time: 5:18
4.15 Minor
25/02/2006
Time: 15:48
4.49 Moderate
20/12/2007
Time: 17:18
3.53 Minor
4/02/2011
Time: 20:06
5.60 Major
12/04/2011
Time: 5:48
3.63 Minor
Figure 5 identifies historical recorded flood locations in the Stonnington
municipality i.e. locations that have flooded where a flood level was recorded.

6.5. Flood Data, Information and Intelligence
There is a range of flood data, information and intelligence held across
Melbourne Water and the City of Stonnington that makes up the existing flood
knowledge base. Table 6.4 briefly summarises where this information is held.
Table 6.4: Available Flood Related Information for Stonnington
municipality
Summary of flood related information available from Melbourne Water
 Asset management system with details of pipes, pits, retarding basins, etc.
 Mapping of flood extents for multiple Annual Exceedance Probability (AEP)
events for main waterways and main drains.
 Flood heights and floor levels for properties within areas delineated in the
Melbourne Planning Scheme as either the Land Subject to Inundation
Overlay (LSIO) or the Special Building Overlay (SBO).
 Some knowledge of flow characteristics within Melbourne Water
catchments (e.g. flow, velocity, etc).
 The municipal cadastre along with knowledge of land use within flood zones
and overlays.
 An understanding of flood history and impacts for Melbourne Water
catchments.
Summary of flood related information available from the City of
Stonnington
 Drainage asset base on GIS with details of pipes, pits, drainage catchments
and retarding basins.
 Mapping of flood extents for 100yr AEP (primarily upstream of Melbourne
Water flood mapping).
 The municipal cadastre along with knowledge of land use within flood zones
and overlays.
 The City of Stonnington Planning Scheme including flood zones and
overlays.
7.Flood Risk
This Section introduces Melbourne Water’s Flood Risk Assessment Framework
(Melbourne Water, 2010), and outlines existing and future flood risk within the
Stonnington municipality.

7.1. Flood Risk Assessment
Melbourne Water uses a Flood Risk Assessment Framework (Melbourne Water,
2010) to identify and assess flood risks, based on a triple bottom line
assessment, considering economic, social and safety factors. The Framework was
developed in consultation with metropolitan Councils and other stakeholders to
provide a more transparent process to help people understand the decision
making and flood mitigation prioritisation process.
The Melbourne Water Flood Risk Assessment Framework assesses flood risk by
catchment based on the following criteria:
Economic
 The cost of flooding, calculated as Average Annual Damages per property.
Safety (Hazard)
 Depth of above-floor flooding (95th percentile);
 Safety factor – product of the depth and velocity of floodwater
(95th
percentile);
 Time for floodwaters to peak (indicator of rate of rise); and
 The primary land use within the catchment.
Social
 Historical above-floor flood frequency;
 Ratio of floors affected in 20-year ARI flood event to floors affected in a
100-year ARI event;
 Disruption to the community based on flood-affected area; and
 Vulnerability of the community within the flood-affected area.
Community
 Community preparedness, i.e. preparedness of the community to deal with a
flood via non-structural flood mitigation measures.
The Flood Risk Assessment Framework classifies flood risks, by catchment, as
low, medium, high or extreme. Extreme flood risks are those considered to be
‘intolerable’. While flooding is a natural occurrence, in some cases the risks from
flooding may be considered intolerable – that is so high that measures should be
put in place to reduce the risks. For those, a range of control measures
embracing both engineering works and non-structural approaches will be
considered with the aim of reducing the risk to a more tolerable level. In most
cases the risk will be reduced but not removed; a residual risk will remain.
As catchments and municipal boundaries do not necessarily coincide, it is
possible that matters giving rise to or contributing to a flood risk may be outside
a municipal boundary (or vice versa). In such circumstances, Melbourne Water
will ensure that the issue will be recognised and considered within the flood risk
prioritisation, particularly in cases where the risk is assessed as being
intolerable.

7.2. Existing Flood Risks within the Municipality
There are a range of existing flood risks within the Stonnington municipality.
Modelling undertaken by Melbourne Water to date has identified 4,859 residential
and commercial/industrial properties within the municipality that are affected by
flooding from waterways and overland flows.
The current list of Melbourne Water flood risks, by catchment, within the
Stonnington municipality is provided in Appendix C. The Melbourne Water
catchment risk ratings for the Stonnington municipality are illustrated in
Figure 6.
The Murrumbeena Main Drain2
, Scotchmans Creek, Chadstone Main Drain,
Prahran Main Drain3
and Tooronga Road Main Drain4
The East Malvern Main Drain has yet to be assessed under the risk framework
and Melbourne Water will be able to continue to update the framework as it
receives new information.
catchments are all classified
as extreme risk. Gardiners Creek, Canberra Road Main Drain, Darling Road Main
Drain, Hedgeley Dene Main Drain and Yarra Street Drain catchments are
classified as high risk (Melbourne Water, 2012a).
The City of Stonnington has identified a range of sites which are considered to
have a high risk of flooding.5
Photo 3: Flooding on
Toorak Road
The sites listed in Table 7.1 and mapped in
Figure 6 are described as flood hot spots. The flood hot spots have a history of
repeated flooding, reported flood drainage, resident responses and high priority
for implementing drainage improvements to Council’s present design standards.
2
The Murrumbeena catchment in Stonnington includes the Chadstone Main Drain subcatchment and Murrumbeena Drain
subcatchment (downstream of the railway line).
3
The Prahran Main Drain Catchment includes the Prahran Main Drain, Essex Street Main Drain, Williams Road Diversion Drain
and Beatty Avenue Main Drain subcatchments.
4
The Tooronga Road catchment in Stonnington includes the Tooronga Road Main Drain and the Creswick Street Main Drain
subcatchments.
5
The City of Stonnington identified high risk sites have not been assessed against the Melbourne Water Flood Risk Assessment
Framework.

Table 7.1: City of Stonnington Flood Hot Spots
Note: not in any order of priority
Site Street Suburb
1 Claremont Street/Yarra Street South Yarra
2 King Street/Cliffton Street/Anchor Place Prahran
3 Chapel Street/Union Street/Windsor Railway Station Windsor
4 Park Road/McMicken Lane Prahran
5 Ross Street Toorak
6 Lansell Road/Dalriada Street Toorak
7 Thanet St/Dixon Street Malvern
8 Edgar Street/Aintree Road/Creswick Street Glen Iris
9 Dorrington Avenue/Sacre Coeur Glen Iris
10 Right of way between Vickery Street and Manning Road Malvern East
11 Millewa Avenue Malvern East
City of Stonnington has identified flash flooding as a risk for the municipality in
the City of Stonnington Municipal Emergency Management Plan 2011 (MEMP).
A number of properties have been identified as flood-prone along Melbourne
Water drains and waterways; and these properties are mapped in Figure 7.
The Stonnington municipality has a range of challenges which influence the
impact, management and risk of flooding. Stonnington is a major hub for
entertainment, recreation and leisure within greater Melbourne. A challenge lies
in effectively mitigating the risks associated with potentially having a large
number of visitors present during a large scale storm event which may cause
flooding and disrupt transport networks. The City of Stonnington could work
closely with VICSES and other stakeholders to focus on emergency management
for both residents and visitors (also see Section 8.7 on community education).
Figure 8 identifies locations where there is a safety risk associated within
flooded roads (to the limited extent that information is available). Risk levels are
defined as:
 High risk: depth is greater than 0.8 m, and/or velocity times depth is
greater than 0.8 m2
/s;
 Moderate risk: depth is greater than 0.4m but less than 0.8m; and/or,
velocity times depth is greater than 0.4m2
/s but less than 0.8 m2
/s; and
 Low Risk: depth is less than 0.4 m; and velocity times depth is less than
0.4 m2
/s.

There is an opportunity for City of Stonnington to review and identify safety risks
in known flood risk areas to increase community understanding of risks and
improve safety. This may require quantifying and measuring safety risk in
roadways (flood depth and velocity) and the threat to the community
(school children, elderly, commuters etc). It could lead to installation of warning
and depth signs at known hot spots (see Improvement Plan Action St-5), such
as recently completed by City of Port Phillip.
7.3. Future Flood Risks
Future flood risks and long term pressures on the drainage system may emerge
from infill development and climate change.
Urban Consolidation and Infill Development
As an established urban area, the Stonnington municipality is largely fully
developed with no significant greenfield development sites remaining. Future
residential development will involve higher density, infill development. Significant
large development sites have been identified in parts of South Yarra, Prahran,
Armadale and Malvern East while Malvern, Toorak-Kooyong and Windsor have
numerous moderate level developments (forecast.id®
The Forrest Hill precinct, bound by Chapel Street, Toorak Road, Alexandra
Avenue and Yarra Street, will have a significant impact on the northern end of
the city. It is projected that by 2031, Forrest Hill will accommodate 2,500
dwellings, office space of 22,000 square metres and retail space over 9,000
square metres. The precinct is currently undergoing substantial change with
some $2 billion in Capital Improved Value based on current development and
existing proposals (City of Stonnington, 2011a).
, 2010).
Infill development may affect overland flow paths and create drainage problems
or exacerbate existing problems in Stonnington. In some locations, the
impervious area may increase to around 80 percent. A key priority for
Melbourne Water and the City of Stonnington will be to continue to understand
the condition and capacity of the drainage system and maintain overland flow
paths in key development areas, especially where infill and higher density
developments are planned to occur (see Improvement Plan Action St-4).
To help manage development impacts, Melbourne Water undertakes
‘Redevelopment Services Schemes’ (RSS). A RSS is an overall plan to identify
how the additional stormwater runoff can be catered for by the existing
Melbourne Water drainage infrastructure and what upgrades may be required to
mitigate or reduce large-scale flooding. There are RSS in Stonnington for the:
Prahran; Canberra Road; Murrumbeena; Lara Street; Moonga Road and
Tooronga Road Main Drains. Melbourne Water is undertaking a general review of
RSSs to find a more effective way of managing infill development.
With ongoing redevelopment in the City of Stonnington, there are increasing
demands for higher design standards in respect of flood management by
residents and the community. A challenge for City of Stonnington is the

additional cost associated with meeting this demand with increasing higher
density development.
Climate Change
Climate change has the potential to increase flood risk within the Port Phillip and
Westernport region, including the Stonnington municipality. While the latest
predictions are for a long-term reduction in storage yield (i.e. a reduction in
runoff volumes) it is likely that the intensity of extreme rainfall events will
increase. The change in rainfall patterns is likely to lead to less frequent (but
possibly larger) riverine flooding and more frequent flash flooding and overland
flow events associated with localised storm activity.
Increased rainfall intensities will impact on Stonnington’s drainage system and
waterways. To improve understanding of possible impacts, Melbourne Water
now includes a climate change scenario when flood modelling and mapping a
catchment. This modelling will be further refined given that the Australian
Rainfall and Runoff (ARR) data on which rainfall estimates in Australia are
typically based is currently being revised to include an improved understanding
of rainfall under current and climate change conditions (Melbourne Water,
2011b).
City of Stonnington has yet to fully consider potential impacts from climate
change on flooding and adaptation responses. For example, it has not
considered the potential impacts of climate change as part of flood modelling.
However, City of Stonnington is responding to a perceived increase in frequency
of storm events that has drainage asset management and resourcing
implications. It will be valuable if Melbourne Water and City of Stonnington can
share information on climate change scenarios, impacts and the implications for
flood mitigation.
8.Flood Management and Mitigation
This Section captures what is being done within the Stonnington municipality to
understand, identify and treat flood risks as well as what is planned to further
improve the management of existing, future and residual flood risks.
8.1. Drainage Strategy
The City of Stonnington has a range of plans and strategies that inform and
guide drainage management within the municipality including the:
 Asset Management Plan (final draft, 2012)
 Stormwater Management Plan (2002)
 Water Sensitive Urban Design (WSUD) Guidelines (2010).
The City of Stonnington has had a rolling 5-year plan aimed at increasing flood
protection for flood-prone properties in its local catchments to accommodate a
1 in 20yr storm event. The City of Stonnington has undertaken many drainage

studies to investigate flood impacts of projects within the municipality and to
solve existing flooding problems on a case by case basis. Following major storms
and flooding in 2010 and 2011, the City of Stonnington is continuing to invest in
drainage upgrades and flood mitigation as part of ongoing drainage system
renewal.
In 2005, the performance of the City of Stonnington in managing the drainage
system was audited by the Victorian Auditor-General as part of a broader audit of
stormwater management across Melbourne. The City of Stonnington was
selected as it had a number of properties in flood-prone areas built before the
late 1970s when drainage capacity standards were increased.
The Victorian Auditor-General found that City of Stonnington was managing its
drainage assets effectively and on some measures rated “excellent”
(Victorian Auditor-General, 2005).
The City of Stonnington has committed to implementing drainage upgrades in
high risk areas through 2012/13 and beyond (see Section 8.5).
8.2. Flood Modelling and Mapping
Accurate survey and modelling of floodplains and overland flow paths is required
to determine flood depths and delineate areas subject to inundation on
floodplains and along overland flow paths. This information is aimed at improving
community safety through informed planning (ensuring that new development is
designed to take into account floodplain and overland flow paths and associated
flow depths) and emergency response. The mapped information is therefore
required not only by Melbourne Water as the floodplain management authority,
but also by municipal planning departments, emergency response organisations,
other infrastructure providers, land developers, prospective land purchasers and
existing land owners and occupiers.
Melbourne Water has undertaken flood modelling of all of its defined main drains
and waterways within the Stonnington municipality. This modelling was carried
out from the mid-1990s to the present. Presently, Melbourne Water is mapping
the following main drains and catchments:
 Gardiners Creek (at data acceptance stage);
 Prahran Main Drain (remapping completed and at flood risk assessment
stage); and
 Murrumbeena Drain (flood risk assessment has been largely completed and
at flood mitigation options assessment stage pending further engagement
with CityLink).
Melbourne Water has also considered climate change scenarios as part of flood
modelling for Murrumbeena and Scotchmans Creek.
The Melbourne Water and City of Stonnington flood extents as modelled for 20yr,
50yr and 100yr events for waterways and drains in Stonnington are shown in
Figure 9. The Melbourne Water modelled flood extents are limited to areas
directly serviced by Melbourne Water assets (i.e. main drains and waterways).

Drains, waterways and 100yr flood extents as modelled in the Stonnington
municipality are shown in Figure 10.
The City of Stonnington has undertaken extensive flood modelling and mapping
of the local drainage network since the late 1990s. It is one of a handful of
Councils in Melbourne to have done this. The City of Stonnington has used this
flood mapping to prioritise mitigation works and identify areas in the SBO in the
City of Stonnington Planning Scheme (see Section 8.4).
8.3. Asset Management
Melbourne Water and the City of Stonnington have a range of flood mitigation
and drainage assets as outlined in Appendix A.
Melbourne Water Asset Management
Drainage and flood mitigation assets are maintained to a ‘fit for purpose’ state
to ensure they work as designed during a flood. All Melbourne Water drainage
assets and waterways have an ongoing inspection and maintenance program.
Melbourne Water drainage assets are managed in accordance with the Asset
Management Guidelines and Strategic Asset Management Plans; for example,
with a level of service of ‘no failure/collapse of significant drains’.
Melbourne Water main drain conditions are assessed and reported annually in
the State of the Assets Report.
CCTV inspections are undertaken as specified in Strategic Asset Management
Plans (SAMP). Further investigations are carried out based on the outcomes of
the CCTV inspection.
Melbourne Water also responds to and undertakes activities, such as:
 Drain repairs as identified in CCTV programs;
 Retarding Basin repairs as identified in inspections;
 Mitigation of underground blockages and subsidence;
 De-silting of drainage channels and sediment traps;
 Tree/vegetation management on Melbourne Water land; and
 Emergency response to pollution spills.
Through each year, Melbourne Water removes litter, debris and excess sediment
from waterways, installs fences for protection, removes and sprays weeds, cuts
grass, plants native trees, plants grasses and manages erosion.
Melbourne Water also responds to events that may cause risk to the public,
assets or environment. In 2010/11, for example, Melbourne Water undertook a
range of works in Stonnington including (Melbourne Water, 2011a):
 Bank stabilisation and flood repair work on Gardiners Creek between
High Street and Burke Street, Glen Iris; and
 General maintenance of waterways across Stonnington, such as weed
control, litter and debris removal, grass management in drainage reserves
and retarding basins, and responses to pollution events.

City of Stonnington Asset Management
Development of a City of Stonnington Asset Management Plan is anticipated to
be completed in 2013.
City of Stonnington has a proactive bi-annual hot spot drain clearing program,
undertaken in March/April and August/September, to ensure that drains are
clear and maintained at maximum capacity. In 2012/13, the City of Stonnington
is undertaking a review of its maintenance and operations plan for drainage
assets to determine if the plan is efficient and effective (see Improvement Plan
Action St-10).
On-ground investigations occasionally reveal “new” drains and these need to be
assessed to determine if they could be accepted as a Council responsibility or
remain as a private drain. It could be useful to establish a policy for how these
“new” drains may be assessed and accepted or rejected by Council.
Vegetation is an important part of the natural character and amenity of the
Stonnington municipality. However, some tree species can block drains and
dislodge kerbs, causing significant cost to the City of Stonnington as it seeks to
maintain drainage assets and reduce flood risk. Recent drainage improvement
designs often result in new drains being located underneath the middle of roads
to reduce impacts on the drainage system and trees in the nature strip.
Photo 4: Tree leaves and
drain
8.4. Planning Controls
Melbourne Water is the Regional Floodplain and Drainage Authority for the
Port Phillip and Westernport region. Applications for subdivision and
developments in areas covered by the Land Subject to Inundation Overlay
(LSIO) and Special Building Overlay (SBO) are referred by Councils Planning
Unit to either Melbourne Water or Council’s Infrastructure Unit. Some types of
minor works are excluded from requiring a planning permit (and referral).
Melbourne Water comments on development applications and, if necessary,
places conditions on planning permits to ensure that the drainage system
continues to function properly and any new developments are adequately

designed to protect people and property from floods and to protect the health of
local waterways (Melbourne Water, 2012c).
The Municipal Strategic Statement (MSS) in the City of Stonnington Planning
Scheme is a concise statement of the key strategic planning, land use and
development objectives for the municipality, and the strategies and actions for
achieving the objectives. The MSS contains the vision for land use development
within the municipality.
In terms of flood risk, key issues in the MSS are (Clause 21.02-01):
 Management of the Yarra River and Gardiners Creek floodplains is critical to
maintaining the ecological values of these waterways and to lessening the
risks of inundation.
 It is important that the risks of inundation of properties are considered when
assessing planning proposals and to avoid inappropriately located uses and
development.
Key strategies relating to flood management in the MSS are (Clause 21.02-01):
 Yarra River and Gardiners Creek: ensure development along the Yarra River
and Gardiners Creek and their floodplains is consistent with floodplain
management objectives.
 Land Liable to Inundation: ensure development on land subject to inundation
is managed to provide for the passage and temporary storage of floodwaters
and to minimise flood damage.
To implement the MSS strategies, the Stonnington Planning Scheme includes
two planning overlays which identify areas subject to flooding in a 1 in 100yr
storm event (see Figure 11):
 The Land Subject to Inundation Overlay (LSIO) (Clause 44.04) – this overlay
identifies areas subject to flooding when Gardiners Creek and the Yarra River
are in flood. The flood mapping has been carried out by Melbourne Water and
is a Melbourne Water responsibility to revise and amend as necessary.
 The Special Building Overlay (SBO) (Clause 44.05) – this overlay identifies
areas subject to flooding when Melbourne Water Main Drains and City of
Stonnington local drains are flowing at full capacity:
o Mapping associated with Melbourne Water Main Drains was carried out
by Melbourne Water and is a Melbourne Water responsibility to revise
and amend as necessary.
o Mapping associated with the Council drainage system was carried out
by City of Stonnington and is a Council responsibility to revise and
amend as necessary.
The broad purpose of the LSIO and SBO is to identify land which is subject to
flooding, to manage development in these areas and to manage flood risk to
people and flood damage to property.

Schedule 1 to the Special Use Zone covering Kooyong Lawn Tennis Club,
St Kevin’s College and Vision Australia Foundation is to provide for the use and
development of education centres and recreation facilities potentially affected by
floodwaters of the Yarra River. It is to also ensure that development maintains
the free passage and temporary storage of floodwaters, minimises flood
damage, is compatible with the flood hazard and local drainage conditions and
will not cause any significant rise in flood level or flow velocity.
The City of Stonnington has 4,945 properties that have been modelled as being
within the 1 in 100 year flood extent and a further 377 properties modelled in
recent flood mapping that need to be included in the SBO. A high priority action
for the City of Stonnington is to update the SBO in the Planning Scheme (see
Improvement Plan Action St-1).
The City of Stonnington has a major focus on considering drainage and flooding
impacts and risks as part of the assessment of planning permit applications.
There has been effective integration and communication between Council’s
engineering and planning units, and also with Melbourne Water. The continued
assessment of drainage and flood risks at the planning permit application stage
has resulted in more appropriate development in known flood risk areas in
Stonnington (see Improvement Plan Action St-6).
Accurate flood levels are required to inform effective planning and development
controls. Council’s Infrastructure Unit require a developer to submit a “Plan of
Survey” for a site, prepared by a licensed surveyor, showing existing ground and
design levels to A.H.D. These levels are compared with the flood mapping data
to ensure accuracy in the establishment of planning conditions such as minimum
floor levels and conditions for maintaining an overland flow path around and/or
clear of obstructions. In some areas there are potential discrepancies which
need to be referred back to the Melbourne Water and Council mapping
consultants for review (see Improvement Plan Action St-2).
Drainage and flooding issues are not always considered at the design stage of a
development. There is a potential role for City of Stonnington to provide
information to developers and architects on the importance of appropriate
design and mitigation of drainage and flooding risks (see Improvement Plan
Action St-13).
The flood-related strategies and planning controls in the City of Stonnington
Planning Scheme will be supported by the development and implementation of
this Flood Management Plan, for example through increased coordination
between Melbourne Water and the City of Stonnington with ongoing revision and
updating of flood overlays.
In the medium term, Melbourne Water could work with the Department of
Planning and Community Development to review the naming of the SBO
(see Improvement Plan Action St-3). The current naming of the SBO does not
clearly indicate that the overlay is to target flooding and mitigate flood risk.
However, any name change would have state-wide implications and would need
to be carefully reviewed.

8.5. Capital Works
Both Melbourne Water and the City of Stonnington undertake a range of capital
works related to drainage and flood management.
Drainage Improvement Capital Works Programs – Melbourne Water
Melbourne Water has a five year Water Plan that documents its proposed capital
works program. The current Water Plan finishes in 2013; it includes $209 million
of proposed expenditure for drainage and flood protection capital works in the
Port Phillip and Westernport region. Melbourne Water is currently prioritising its
capital works program for Water Plan 3 for the next five years. Depending on
final priorities, Melbourne Water will undertake a range of capital works and
flood studies to reduce flood risk in the extreme risk rated catchments in
Stonnington, such as the joint project to upgrade drainage in the
Creswick/Tooronga Catchment.
Melbourne Water includes projects into the Water Plan (and onto capital works
programs) based on a number of criteria including works to:
 Reduce extreme flood risks;
 Renew assets; and
 Improve stormwater quality.
The focus of the Port Phillip and Westernport Region Flood Management and
Drainage Strategy (Melbourne Water, 2007a) is on reducing “intolerable” flood
risks; catchments with an extreme rating will have priority followed by high risk
catchments. There are five extreme risk catchments in the Stonnington
municipality with six high risk catchments (see Section 7.2).
Drainage Improvement Capital Works Programs – City of Stonnington
The City of Stonnington has a capital works program that includes drainage
assets. The City of Stonnington 2009-2013 Council Plan is the overarching plan
and the Adopted 2012/13 Budget outlines priorities for the operating, capital
and maintenance programs in the 2012/13 financial year (City of Stonnington,
2012).
The City of Stonnington budgeted capital works statement for the next five
years is outlined in Table 8.1.
Table 8.1: Capital works statement – Drainage
Asset
Class
Forecast Budget Strategic Resource Plan
2011/12 2012/13 2013/14 2014/15 2015/16
Drainage $1,696,000 $1,968,000 $1,986,000 $2,023,000 $2,090,000
Source: City of Stonnington, 2012.

In its 2012/13 budget statement, City of Stonnington has identified that it will
continue with a series of strategic activities relating to drainage and flood
management including (City of Stonnington, 2012):
 Continuing to undertake footpath and drainage improvements to the
Glenferrie Road Shopping Centre, Malvern;
 Undertaking the drainage pit modernisation program to improve system
performance;
 Continuing to undertake improvements to the drainage system to extend
drain life, improve stormwater flow and flood impacts in selected sites;
 Continuing to revise the Special Building Overlay flood mapping to identify
drainage improvement options.
 Continuing to undertake stormwater CCTV surveys to monitor the condition
of Council’s drain network to determine future drain relining and maintenance
programs; and
 Undertaking a stormwater drain pollution trap and pit maintenance and
cleaning program to reduce rubbish entering waterways.
In 2012/13, City of Stonnington has budgeted to spend approximately
$1.97 million on Council’s drainage assets including (City of Stonnington, 2012):
 Edgar Street/Osbourne Avenue drainage works ($0.95 million);
 Millewa Avenue drainage works ($0.4 million);
 Nott Street drainage improvements ($0.3 million); and
 A drainage relining program ($0.15 million).
The City of Stonnington and Melbourne Water are seeking to find efficiencies in
capital works, for example, joint upgrade projects, such as the Edgar Street
drain.
The continuing large-scale development and extension of the Chadstone
Shopping Centre will impact on flooding and waterway quality. There may be
potential to incorporate drainage improvements under the proposed extension.
The City of Stonnington has approached the Chadstone Shopping Centre
regarding a potential financial contribution to fund works around Gardiners
Creek.
Over time, Melbourne Water and City of Stonnington could seek to establish a
partnership with the Chadstone Shopping Centre to achieve better drainage and
waterway outcomes. This would also contribute to the further identification of
opportunities to enhance Gardiners Creek and its tributaries in terms of flood
mitigation and erosion control. Melbourne Water has an existing project to widen
a section of Gardiners Creek to increase flood protection for local residents.
In the future, there is potential for an integrated flood study of the Union Street
Main Drain catchment, Prahran. This is a low-lying area and there are limited
flood risk mitigation options to City of Stonnington. This study will require
involvement from Melbourne Water, the Cities of Stonnington and Melbourne (as

the area crosses the municipal boundary), and potentially from other
organisations, such as VicRoads (see Improvement Plan Action St-9).
Photo 5: New drainage pits, South
Yarra
8.6. Flood Emergency Planning
Planning is crucial to ensuring an effective proactive emergency response to
flooding. Planning must be conducted within the legislated framework as well as
having a process that is established and well understood by all stakeholders.
Further, planning must be based on a sound understanding of flood risk. In
addition, communication and consultation are essential in achieving ownership
of flood emergency plans by all stakeholders, especially the community.
Ownership of flood emergency plans ensures that stakeholders are more likely
to respond to floods in accordance with strategies and arrangements detailed in
the plan.
Municipal Emergency Management Plan (MEMP) and Flood Emergency Plan
Flood response and recovery arrangements are as detailed in the City of
Stonnington Municipal Emergency Management Plan 2011 (MEMP) and MEMP
Flood Emergency Plan.
The City of Stonnington MEMP outlines that key control measures are already in
place to assist with flash flooding caused by a heavy downpour and rapid
inundation of low-lying areas. These include the Flood Management Plan,
warnings on Council’s website, mapping and maintenance of stormwater drains,
enforcement of Building Codes, Recovery Sub Committee processes and MEMP
Communications. In addition, the VICSES, Victoria Police and Melbourne Fire
Brigade are equipped to respond (City of Stonnington, 2011b).
VICSES has implemented a Regional Flood Response Plan which, together with
the State Flood Response Plan, will facilitate a consistent and coordinated
approach to flood response within the Municipality in the lead up to, during and
after a flood event.

In developing this Flood Management Plan, Melbourne Water and the City of
Stonnington have collated a range of information relating to flooding from
waterways and overland flows within the Municipality. The intelligence in this
information will be used as a basis for the development of a Flood Emergency
Plan with VICSES, as a sub-plan of the Municipal Emergency Management Plan
(MEMP) (see Improvement Plan Action St-12).
Linkage with MEMP Flood Emergency Plan
All information and intelligence developed and collated as part of this Flood
Management Plan and as a result of the studies and work that flow from its
implementation should, as a matter of course, be made available to the MERO
for consideration and incorporation into the Flood Emergency Plan.
Similarly, during and immediately after a flood it is important that key aspects
of the event are recorded so that the MEMP Flood Emergency Plan and its
associated actions can be improved, and future flood damage better contained.
Arrangements for data collection and collation are detailed in the MEMP Flood
Emergency Plan. The information collected and intelligence extracted therefore
needs to be used to inform this Flood Management Plan.
Figure 12 identifies a number of key services and vulnerable areas within the
Stonnington municipality that could be affected by flooding including:
emergency services; hospitals; schools; and childcare facilities.
Individual Flood Preparedness Plans
There is no information on whether any individual flood preparedness plans have
been developed or are planned for development by businesses or organisations
within the Stonnington municipality. If prepared, these plans could be listed
within the Flood Emergency Plan, for example, for areas of high risk from flash
flooding and overland flows.
8.7. Community Education and Awareness
City of Stonnington, Melbourne Water and VICSES are committed to working
together before, in the lead up to and during periods of flooding, to create
awareness within the community of preparedness measures that have been and
should be taken.
VICSES is implementing a number of flood management education programs,
including StormSafe and FloodSafe, across Victoria. City of Stonnington
recognises the need to work to ensure that residents, business owners and
operators, and visitors are aware of the flood risk and of appropriate flood
response actions. VICSES and City of Stonnington will be able to work together
to develop and implement an appropriate community education program (see

Flood zones and overlays in the Stonnington Planning Scheme also raise
community awareness of flooding issues. The notification of the amendment,
along with the inclusion of flood maps as overlay controls, makes flooding
information readily accessible to the community and ensures that site
constraints and likely development requirements are flagged to developers and
property owners. Planning information, including flooding overlays, is disclosed
to prospective purchasers through planning certificates issued under Section 199
of the Planning and Environment Act (1987) and included as a compulsory part
of the vendor’s statement issued under Section 32 of the Sale of Land Act
(1962).
8.8. Flood Warning Systems
Flood warning systems and services aim to reduce the losses and hardship
caused by flooding and are important flood mitigation measures. Flood warning
systems and services are an integral part of emergency management and
influence community response during flood events, by reducing avoidable
damage, the potential for loss of life, and disruption to normal community
activities caused by flooding (Bureau of Meteorology, 2001).
Emergency warnings are intended to achieve two important outcomes; firstly to
inform those at risk of an impending or current threat, and secondly that
appropriate actions are taken by those at risk. As no one method of providing a
warning will reach all the intended recipients, a variety of warning methods are
generally used including: radio; television; email; telephone – voice message
and short message service (SMS) or text alerts; doorknocking; internet
including social media (such as Twitter and Facebook); and verbal (face to face,
community meetings, etc) (Emergency Management Australia, 2009).
Within the City of Stonnington, Melbourne Water has a flood warning system in
place at Gardiners Creek at Great Valley Road, Gardiner. However, flood
warnings are not issued for the catchment due to the short response times.
Melbourne Water does inform the VICSES about potential local flooding issues.
The highest recorded flood level for the Gardiners Creek monitoring site is
5.6 metres on 4 February 2011.
Occupants of an apartment building in Malvern have expressed concerns to the
City of Stonnington about localised flooding and damage to vehicles and
property in a basement car park resulting from flash flooding caused by major
storms. The City of Stonnington is not responsible for providing storm warnings
to property owners, local residents and businesses but it could provide general
information on flood/storm warning systems, such as on the Council website.
Aspects to be considered with the design and implementation of any flood or
storm warning system by property owners, local residents and businesses
include:
 How to effectively gather and receive data on potential storm events or flash
flooding for a localised area (such as Bureau of Meteorology storm warnings
or Melbourne Water flood warnings);

 How much time is required for action to be taken by residents and businesses
once a warning is received, for example, to enable safe removal of vehicles
from basement car parks;
 What are the most appropriate communication methods (further discussed
below);
 The content and language of the warning message (i.e. would it instruct
occupants to take action or prompt them to seek further information?);
 Documentation of the decision-making process and delegation of power for
issuing a warning or alert; and
 The legal implications of providing a warning to residents and businesses
including the risks of legal action if there were inaccurate warnings.
As outlined above, a range of communication methods are available but for
timely and accurate warnings, telephone, SMS or email alerts are considered the
most effective. An alert system could broadcast pre-recorded voice or text
messages to specific telephones and mobile phones simultaneously, providing
residents and businesses with flood/storm warning information. A further option
could involve placing warning sirens in at-risk buildings.
Several issues with implementation of telephone- or message-based warning
systems are:
 How to develop and maintain an accurate register of telephones and mobile
phones for each resident and business in at risk buildings with basement car
parks (noting this may be difficult in buildings with high turnover of residents
or businesses);
 How to address language and accessibility issues in terms of providing a clear
but succinct warning message; and
 If required, how to confirm receipt and acknowledgment of the warning
message.
Vision Australia on Glenferrie Road has a flood warning system for its building
and basement car park. The building manager is alerted if flood levels are
reached and the emergency response plan can be activated. This approach could
be further investigated for at-risk apartment buildings within Stonnington by the
property owners.
An alert system that directs residents to a ‘floodwatch’ website and/or emergency
preparedness website would support residents and businesses in making
well-informed decisions about their actions and safety, including when to inform
neighbours about received alerts. Education programs could also inform residents
and businesses about the variety of Federal, State and local emergency warning
systems and encourage residents to register and/or update telephone contact
details for emergency warning registers, such as the federal Emergency Alert6
or
The Australia Early Warning Network7
6
Source: http://www.emergencyalert.gov.au/
.
7
Source: http://www1.ewn.com.au/register/register.aspx

Following development of this Flood Management Plan, there is an opportunity
for the City of Stonnington to further investigate options for providing general
information on storm warning systems where this is considered appropriate (see
8.9. Drainage studies and guidelines
Melbourne Water, City of Stonnington and other organisations have undertaken
a range of waterway and drainage studies, and developed plans and guidelines
to address flooding and stormwater management.
Guidelines for Development in Flood-prone Areas
Melbourne Water has developed guidelines to assist property owners,
developers, designers and builders to understand the broad principles and
specific requirements that apply to property development in flood-prone areas
within the Melbourne metropolitan area. The guidelines address requirements in
both floodplain and overland flow path areas and supplement the Land
Development Manual (Melbourne Water, 20108
Drainage Studies
).
Various drainage studies have been completed within the City of Stonnington
focussing on areas at high risk of flooding and to support drainage upgrades.
Water Sensitive Urban Design Guidelines
The City of Stonnington together with Melbourne Water have developed Water
Sensitive Urban Design (WSUD) guidelines (City of Stonnington and Melbourne
Water, 2010). The WSUD Guidelines inform Council staff, developers and
residents on how to apply WSUD principles to urban developments or local water
reuse projects. These guidelines provide information, strategic advice and
practical tips on implementing WSUD in a structured way. A key outcome of
implementing WSUD is to reduce the impact of increased stormwater runoff on
the drainage system.
Increased development and runoff due to an increase in impervious areas,
especially in the east of the city, will bring further opportunities for potential
application of WSUD and integrated water management solutions. There is
potential to investigate the effectiveness of rainwater tanks as opposed to
detention tanks for the management of runoff.
Sustainable Water Management
The City of Stonnington has also demonstrated leadership in sustainable water
management through the adoption and implementation of its Stormwater
Management Plan (2002) and Sustainable Water Management Strategy (2005).
8
Melbourne Water (2010), Land Development Manual (note that this is an online document subject to ongoing updates).

9.Roles and Responsibilities
The Port Phillip and Westernport region faces significant flood management and
drainage challenges that require a coordinated approach between agencies. The
aim to reduce existing and future flood risk and manage residual flood risk
includes a variety of structural and non-structural measures. Examples are
retarding basins, levees, floodplains, capacity works, floodgates, flood warning
systems and education programs. It is not possible for one agency or
stakeholder to deliver on all these measures; therefore, an integrated approach
is required.
A clear understanding and common agreement on roles and responsibilities is
necessary for effective collaboration between Melbourne Water, local councils
and VICSES. A summary of key stakeholder roles and responsibilities is provided
in Appendix B. A description of these roles for Melbourne Water and City of
Stonnington is provided below.
In the context of the Port Phillip and Westernport Region Flood Management and
Drainage Strategy and this Flood Management Plan, the above leads to the
following expectations within each agency’s area of management.
Agreed Responsibilities
That Melbourne Water will:
 Provide Councils with technical and financial assistance in the preparation
and maintenance of a Flood Management Plan (this document) that identifies
existing flood risks, intolerable risks, and prioritises works and activities
aimed at reducing risks and improving regional flood management;
 Assist with funding and management of prioritised works and activities
identified in the Flood Management Plan and in their implementation (as
required) at a regional level;
 Provide financial and technical support to Councils and VICSES to deliver
community flood education, awareness and preparedness across the region;
 Continue to support the City of Stonnington in land use management and
other activities aimed at reducing existing and future flood risk; and
 Provide the City of Stonnington with the results of studies and analysis as
well as data gathered during and after flood events for inclusion in the Flood
Emergency Plan.
That City of Stonnington will:
 Work with Melbourne Water to prepare and maintain a Flood Management
Plan (this document) that identifies existing flood risks, identifies intolerable
risks and prioritises works and activities aimed at reducing that risk and
improving regional flood management;
 Assist in facilitating the delivery of prioritised works and activities identified
in the Flood Management Plan and in their implementation (as required)
within the municipality with due regard for inter-municipality issues;

 Incorporate flood mapping outputs into the Planning Scheme as appropriate
zones and overlays and ensure that the flood provisions are sufficient and
consistent with assessed risk and the aim of reducing existing and future
flood risk and damages;
 Support VICSES in the delivery of programs aimed at enhancing community
flood education, awareness and preparedness across the municipality; and
 Maintain the Flood Emergency Plan as a joint owned plan with VICSES,
through routine review and incorporation of intelligence extracted from
relevant studies and analyses and through operational experience.
Improved Collaboration
Melbourne Water, Councils and other flood management stakeholders have
recognised the need for an integrated and sustainable approach where
responsibility for activities is assigned on the capability of the agency to deliver.
While key agencies can demonstrate the provision of specialised flood
management skills in the planning for, response to and recovery from flooding,
there are opportunities to strengthen regional flood management arrangements
through greater collaboration and more efficient use of resources. The
collaborative development of this Flood Management Plan and the Flood
Emergency Plan for Stonnington provides a basis for improved coordination and
collaboration involving both technical and financial contributions. There has been
significant collaboration already between Melbourne Water and City of
Stonnington concerning flooding and drainage issues.
10. Communication
Flood management agencies have a responsibility to communicate with each
other in order to share information, ensure effective planning and coordination,
and identify opportunities for collaboration. This is achieved through the
communication objectives below:
 Raising the profile of Flood Management Plans;
 Improving understanding of Melbourne Water’s and City of Stonnington’s role
and challenges in flood management;
 Promoting achievements of the collaboration between City of Stonnington
and Melbourne Water;
 Aligning flood mitigation objectives/priorities; and
 Aligning of external affairs; the City of Stonnington and Melbourne Water
have joint responsibility for flood and drainage management in
communications with residents, councillors, politicians and media. Also ‘cc’
each other into relevant correspondence issued by either organisation.
Agencies also are required to share information with the public to ensure they
have access to information about flooding and flood risk. This is achieved
through:

 Responding to requests for Property Information Statements which contain
information on land liable to flooding and City of Stonnington drains external
to the property (City of Stonnington);
 Providing an on-line 24-hour a day rainfall and river level monitoring network
(Melbourne Water); and
 Providing community flood education information (VICSES and Melbourne
Water).
Melbourne Water provides a range of information to City of Stonnington through
the sharing of the following datasets (in respect of the assets that it manages):
 Underground Drain Locations (Abandoned Centreline, Centreline and
Alignment);
 Channel Locations (Alignment, Centreline) and Structures;
 Natural Waterways (Alignment, Centreline);
 Retarding Basins;
 Underground Drain Manholes;
 Natural Drain Features;
 Melbourne Water Catchments; and
 1 in 100yr Flood Extent – Underground Drain and Natural Waterways.
Continued information sharing, especially of strategic priorities, flood mapping
programs and five year plans, will support effective flood management across
agencies (see Improvement Plan Action St-7).
11. Improvement Plan
This Section of the Stonnington Flood Management Plan lists activities planned by
the City of Stonnington in conjunction with Melbourne Water (and other
organisations) in order to reduce flood risk and the associated level of intolerability.
It reflects an understanding of the flood risks and proposes a program for mitigating
those risks within Stonnington that are assessed as being appropriate with regard to
local and regional issues and priorities.
The actions below outline the agreed approach to managing existing regional flood
problems within Stonnington. The actions were identified through a gap analysis
performed on flood mitigation and management measures to identify areas
requiring improvement. The relative priority of each action was determined by
assessing:
 The feasibility of an action being implemented as Low (L), Medium (M) or
High (H); and
 The benefit of that action being implemented as Low (L), Medium (M) or
High (H).
The result of these assessments determined an overall priority grading of high
priority, medium-high priority, and medium priority actions. The lead
organisation responsible for each action is identified in bold.

Action Plan: Proposed Activities Aimed at Reducing Flood Risks in the Stonnington Municipality
Action Context
(why is it an
issue)
Feasib-
ility
Benefit Priority Tasks Timing Respons-
ibility
Comments
A. Flood Mapping and Mitigation
St-1 Update the
City of
Stonnington SBO
to incorporate
revised flood
extents
Accurate
planning
overlays will
assist with
identification
of flood risk
and promote
more
appropriate
development
in areas of
known flood
risk.
Medium High High CoS to update
the SBO with
revised flood
extents.
Dec 2016
(report to
Council)
CoS/MW Council and Melbourne Water have
completed flood mapping for both
Council and Melbourne Water drains.
In 2004 these maps were included
in the Stonnington Planning Scheme
as a SBO. Subsequent Council
mapping revisions indicate there are
approximately 377 more properties
which need to be included.

Action Context
(why is it an
issue)
Feasib-
ility
ibility
Comments
St-2 Review flood
levels
Accurate flood
levels are
required to
inform
planning and
development
controls.
High High High a. CoS to
provide MW
with potential
locations to
improve the
accuracy of
flood levels.
b. MW to
review sample
of flood levels
and determine
if there is a
problem and
an appropriate
response.
June
2013
June
2013
CoS/MW Accurate flood levels are required to
inform planning and development
controls. There is a concern that in
some areas the mapping is
inaccurate. Such areas need to be
referred to the flood mapping
consultants for possible revision.
For properties within the SBO,
Council requires a developer to
submit a plan by a qualified
surveyor with levels to A.H.D. to
check any inaccuracies in the flood
mapping.

Action Context
(why is it an
issue)
Feasib-
ility
ibility
Comments
St-3 Review the
naming
convention of the
SBO to enhance
clarity and
community
understanding
An improved
naming
convention
for the SBO
will help the
community to
understand
flood risk and
promote
appropriate
development
in known
flood risk
areas.
Low Medium Medium MW to discuss
with DPCD the
viability of
changing the
naming
convention of
the SBO to
promote
greater
understanding
of flood risk
by property
owners and
the
community.
Dec 2014 MW This would have state-wide
implications with changes required
to the Victoria Planning Provisions.
It may take time to review and
progress.

Action Context
(why is it an
issue)
Feasib-
ility
ibility
Comments
B. Planning, Information and Coordination
St-4 Continue to
improve
protection of
overland flow
paths
Protection of
overland flow
paths will
help to
minimise
flood risk and
promote more
appropriate
development
in known
flood risk
areas.
Medium High Medium –
High
a. Continue to
protect
overland flow
paths by
implementing
appropriate
planning
conditions on
new
developments.
b. Consider
purchasing
properties to
maintain
overland flow
paths where
there is
significant
value to
Council.
Ongoing CoS In some catchments overland flow
paths have been protected by their
development as public gardens,
recreation areas (sports fields,
natural bush) or roads. However,
the overland flow paths often
become partly obstructed where
building allotments and roads have
been set out across natural valleys.
It is also becoming increasingly
difficult to maintain or reduce the
existing degree of obstruction as
allotments become more intensely
developed.

Action Context
(why is it an
issue)
Feasib-
ility
ibility
Comments
St-5 Review
approach to safety
risks at known
flood hot spots
Identification
of safety risks
in known
flood risk
areas will
increase
community
understanding
of risks and
improve
safety.
Medium Medium Medium a. CoS to
consider
warning signs
at known
flood hot
spots (e.g.
installing
warning and
depth signs).
Dec 2013
(ongoing)
CoS Presently there are no warning signs
at locations on roads where flooding
occurs.

Action Context
(why is it an
issue)
Feasib-
ility
ibility
Comments
St-6 Continue to
assess drainage
and flooding
issues as a part of
planning permit
applications
Assessment
of flood risk
at the
planning
permit
application
stage will
promote more
appropriate
development
in known
flood risk
areas.
High High High a. Continue to
assess
drainage and
flooding
issues as a
part of
planning
permit
applications.
b. Consider
establishing
an internal
procedure to
formalise this
assessment
process.
Ongoing CoS This process has been developed to
a high standard since the adoption
of the LSIO and SBO. Continual
effort and co-operation is needed
between respective organisations
and departments involved in the
planning and building process.

Action Context
(why is it an
issue)
Feasib-
ility
ibility
Comments
St-7 Exchange of
flood mapping and
other information
Exchange of
flood mapping
and other
information
will support
effective flood
management
across
organisations.
High Medium Medium –
High
a. CoS to also
provide MW
with latest
flood extents/
shapes to
support
consistent
planning
advice.
b. CoS and
MW to
improve
information
sharing and
exchange
respective 5
year plans.
Ongoing CoS/MW A range of Council divisions and
areas have an interest in drainage
and flood management.

Action Context
(why is it an
issue)
Feasib-
ility
ibility
Comments
St-8 Hold an
annual FMP review
meeting
An annual
meeting will
help ensure
progress is
being made
with key
actions and
that the FMP
is current.
High
a. Organise
and hold
annual review
meetings.
b. Consider
any joint
proposals for
projects to
mitigate flood
risk.
Dec 2013
(ongoing)
MW/CoS/
VICSES
Melbourne Water and Council will be
able to continue to share
information on flood mapping
priorities, investigations and
upgrade works. This is already
occurring but an annual review
meeting will support more rapid and
increased transfer of information.

Action Context
(why is it an
issue)
Feasib-
ility
ibility
Comments
St-9 Consider an
integrated flood
study of the Union
Street Main Drain
catchment,
Prahran
Mitigation of
flooding of
the Union
Street Main
Drain
catchment,
Prahran, will
require
cooperation
from several
organisations
and Councils
as it crosses
the
Stonnington
and Port
Phillip
municipal
boundary.
Medium High Medium-
High
a. Assess and
discuss the
value of an
integrated
flood study.
b. If agreed,
conduct the
study and
implement
appropriate
mitigation
options.
Dec 2013
Dec 2015
MW/CoS/and
others
This catchment is an intensely
developed residential/commercial
area. A difficulty in improving the
drainage system is the limited
capacity of the outfall drain.

Action Context
(why is it an
issue)
Feasib-
ility
ibility
Comments
C. Maintenance and Asset Management
St-10 Review
drainage asset
maintenance by
City of
Stonnington
Effective
drainage
maintenance
will support
flood risk
management
and help
maintain
drainage
asset
condition.
Medium High Medium –
High
Undertake the
scheduled
review of the
CoS
maintenance
and
operations
plan for
drainage
assets.
Dec 2013
(ongoing)
CoS Council is currently preparing a
Drainage Asset Management Plan.

Action Context
(why is it an
issue)
Feasib-
ility
ibility
Comments
St-11 Share
information on
drainage
maintenance
regimes and
priorities
Information
sharing on
maintenance
regimes will
allow for
more efficient
and greater
coverage of
drainage
maintenance,
an increased
understanding
of CoS and
MW drainage
maintenance
and priorities.
Medium Medium Medium CoS and MW
to share
information on
drainage
maintenance
regimes.
Ongoing MW/CoS

Action Context
(why is it an
issue)
Feasib-
ility
ibility
Comments
D. Flood Education and Emergency Planning
St-12 Prepare a
Flood Emergency
Plan
To facilitate a
consistent
and
coordinated
flood
response by
CoS and
VicSES.
High High High a. Prepare a
City of
Stonnington
Flood
Emergency
Plan.
b. Implement
actions in the
City of
Stonnington
Flood
Emergency
Plan (if
contains
actions).
June
2013 /
Ongoing
VICSES/CoS
(and others)
To follow after preparation of this
Flood Management Plan.

Action Context
(why is it an
issue)
Feasib-
ility
ibility
Comments
St-13 Consider
providing
information to
developers and
architects on
mitigation of
drainage and
flooding risk and
appropriate design
Drainage and
flooding
issues are not
always
considered at
the design
stage of a
development.
Medium
– Low
Medium Medium a. Investigate
the
development
of an
information
sheet (or
similar) to
increase
awareness
and mitigate
drainage and
flood risk at
the design
stage.
b. If prepared,
provide the
information
sheet to
developers
and architects
and consider a
targeted
education
program.
Dec 2014
(ongoing)
CoS (plus
others MW,
DPCD, MAV,
etc)
This action may be able to be
considered jointly with neighbouring
councils and/or industry
associations.

Action Context
(why is it an
issue)
Feasib-
ility
ibility
Comments
St-14 Develop and
implement a
community flood
education program
Lack of
community
education and
awareness
will impede
flood
mitigation
and increase
risks from
flooding. A
flood
education
program will
contribute to
community
resilience to
flood events.
High
a. Identify key
flood
education
messages.
b. Develop
flood
education
strategy.
c. Implement
flood
education
activities
including
FloodSafe and
StormSafe.
d. Consider
options to
warn/educate
individual
owners in
flood-prone
areas.
Dec 2014
(ongoing)
VICSES/CoS Links with St-12.

Action Context
(why is it an
issue)
Feasib-
ility
ibility
Comments
St-15 Further
investigate
provision of
general
information on
flood warning
systems
Effective flood
warning
systems may
assist
property
owners to
mitigate or
limit damage
from localised
flooding.
Low High Medium –
High
a. Further
investigate
options for
providing
general
information on
storm warning
systems so
that
occupants and
property
owners of
buildings
prone to
localised
flooding can
take
appropriate
action.
Dec 2014 CoS This is a particular issue where
buildings have been constructed
prior to the adoption of the LSIO
and SBO. Warning times are very
short for properties in the SBO (less
than 30 minutes) but it may be
possible to provide a warning
system for “Body Corporate” sites
with basement parking. This action
also links with St-14.
Key:
MW= Melbourne Water
CoS= City of Stonnington
VICSES= Victorian State Emergency Service
DPCD= Department of Planning and Community Development

MAV= Municipal Association of Victoria.
Note:
In each of the four categories of improvement actions (i.e. Flood mapping and mitigation; Planning, information and
coordination; Maintenance and asset management; and Flood education and emergency planning), the improvement
actions are listed in relative order of priority. These actions were identified and discussed over two workshops held in
May and June 2012 at City of Stonnington and were subsequently prioritised in terms of feasibility and benefit.

12. Monitoring and Review
This Flood Management Plan is a “living document”. As such it will need to be
reviewed each year at an annual meeting to ensure that it continues to
accurately reflect flood risks and their treatment within the City of
Stonnington as well as prevailing statutory and policy requirements (see
Improvement Plan Action St-8). It should also be revised at least every
five (5) years to reflect achievement of work program objectives and changes
to work program priorities. While Melbourne Water will assist with the revision
process, it will need to be driven and managed by the City of Stonnington.
Unless scheduled otherwise, it is suggested that the review and revision
processes should occur immediately before the annual budget cycle so that
maximum opportunity can be made of available funding sources and
processes in partnership with stakeholder entities.
Melbourne Water will be responsible for initiating review and updates with the
City of Stonnington. Melbourne Water and the City of Stonnington will track
and report to each other on actions in the Improvement Plan on a twelve
monthly basis.
Document control
This version:
Version Number Rev 3
Date April 2013
Frequency of Review Five yearly or earlier as required
Next Review Due By end December 2017
Responsible Melbourne Water
officer
Project Manager Flood Strategy
Implementation, Floodplain Services,
Melbourne Water
Responsible Council officer Team Leader, Infrastructure Design and
Project Management, City of Stonnington
Melbourne Water Approved by Manager Floodplain Services,
Melbourne Water
Council Approved by Manager Public Spaces and Capital Works,
City of Stonnington
Document history:
Version Date Comments/changes
Issue 1, Rev 0 18 June 2012 Draft Plan
Issue 1, Rev 1 3 October 2012 Final Draft Plan
Issue 1, Rev 2 17 December 2012 Final Plan
Issue 1, Rev 3 8 April 2013 Final Plan (Revised)

13. How this document was developed
Melbourne Water, City of Stonnington and the Victoria State Emergency
Service worked in partnership with a consultancy, Halcrow Pacific Pty Ltd
(Halcrow), to develop this Flood Management Plan.
The plan was developed through a series of interviews, file reviews, meetings,
site visits and workshops to gather the background information, identify flood
risk management and mitigation activities and arrangements, undertake a gap
analysis and develop an improvement plan. A list of workshop attendees is
presented in Appendix D.
This document was prepared by Halcrow with significant input from Melbourne
Water, City of Stonnington, VICSES and VicRoads.
14. Acknowledgements
Melbourne Water acknowledges the contribution of employees of City of
Stonnington, VICSES, VicRoads, and the Halcrow project team, in preparing
this document.

Abbreviations and Acronyms
The following abbreviations and acronyms are used in this Flood Management
Plan.
AEP Annual Exceedance Probability
ARI Average Recurrence Interval
CBD Central Business District
CCTV Closed Circuit Television
GIS Geographic Information System
LSIO Land Subject to Inundation Overlay
MEMP Municipal Emergency Management Plan
MERO Municipal Emergency Resource officer
SBO Special Building Overlay
VICSES Victoria State Emergency Service
WSUD Water Sensitive Urban design

Glossary
Below are terms defined for the purpose of this Plan.
Term Definition
Drainage system A series of drains and waterways into which surface
and stormwater flows. Features of a drainage
system can include underground pipe drains, open
channels, retarding basins, floodways, waterway
improvements, water quality works and
environment protection measures.
Overland flooding Inundation by local runoff caused by heavier than
usual rainfall. Overland flooding can be caused by
local runoff exceeding the capacity of an urban
stormwater drainage system or by the backwater
effects of mainstream flooding causing urban
stormwater drainage system to overflow.
Floodplain Area of land adjacent to a creek, river, estuary,
lake, dam or artificial channel, which is subject to
inundation by the probable maximum flood.
Natural drainage systems Flowpaths which are largely undeveloped by human
sources, these include rivers, streams, natural
depressions and wetlands. All natural systems
greater than 60 ha are managed by Melbourne
Water.
Hot spot A known flood problem area which has a history of
repeat flooding of a road, crossing or property,
often highlighted through anecdotal information
and customer complaints. It is a localised issue
which will vary from council to council.
Runoff The amount of rainfall that enters the stormwater
drainage system, (underground pipes, overland
flow paths, floodway and waterways) after losses,
such as infiltration has been taken into account.
Flash flooding Sudden unexpected flooding caused by local heavy
rainfall or rainfall in another area. Often defined as
flooding which occurs within six hours of the rain
which causes flooding.

References
Bureau of Meteorology (2001): Arrangements for Flood Warning Services in
Victoria.
City of Stonnington (2012): Adopted 2012/2013 Budget.
City of Stonnington (2011a): City of Stonnington Annual Report 2010/11.
City of Stonnington (2011b): Municipal Emergency Management Plan 2011.
City of Stonnington (2010): Economic Snapshot.
City of Stonnington and Melbourne Water (2010): City of Stonnington WSUD
Guidelines, Applying the Model WSUD Guidelines.
Emergency Management Australia (2009): Manual 21 – Flood Warning,
Attorney-General’s Department, Barton.
Forecast.id®
(2012): City of Stonnington Population Forecasts,
http://forecast2.id.com.au/Default.aspx?id=249&pg=5000,
accessed 13/6/12.
Forecast.id®
(2010): City of Stonnington City Council Population and
Household Forecasts.
Melbourne Water (2012a): Flood Risk Matrix (Extract), May 2012.
Melbourne Water (2012b): List of Floods Exceeding Flood Class Levels for
Gardiners Creek at Gardiner, Melbourne.
Melbourne Water (2012c): Information for Developers,
http://www.melbournewater.com.au/content/planning_and_building/informati
on_for_developers/information_for_developers.asp?bhcp=1,
accessed 12/6/12.
Melbourne Water (2011a): Waterways Local Update: City of Stonnington,
July 2011, Melbourne.
Melbourne Water (2011b): Melbourne Water Floodplain Modelling and Mapping
Specifications, Melbourne.
Melbourne Water (2010): Flood Risk Assessment Framework, June 2010,
Melbourne.
Melbourne Water (2007a): Port Phillip and Westernport Region Flood
Management and Drainage Strategy, November 2007, Melbourne.
Melbourne Water (2007b): Port Phillip and Westernport River Health Strategy,
Melbourne.
Victorian Auditor-General (2005): Managing stormwater flooding risks in
Melbourne, Melbourne.

Appendix A – Asset List
This Appendix contains a list of waterways, drainage assets and other related
infrastructure (e.g. drainage pipes, retarding basins and levees) within the
City of Stonnington.
Melbourne Water Main Drains and Waterways
Melbourne Water has 18 Main Drains and Drains within the Stonnington
municipality (see Table A1.1) with an approximate length of 22.6km.
There are three major waterways: the Yarra River, Gardiners Creek and
Scotchmans Creek.
Table A1.1: Melbourne Water Main Drains/Drains
Murrumbeena Main Drain Chadstone Main Drain
East Malvern Main Drain Scotchmans Creek Main Drain
Darling Road Main Drain Hedgeley Dene Main Drain
Creswick Street Main Drain Tooronga Road Main Drain
Lara Street Main Drain Moonga Road Main Drain
Beatty Avenue Main Drain Prahran Main Drain
Canberra Road Main Drain Williams Road Main Drain
Surrey Road Main Drain Essex Street Main Drain
Union Street Main Drain Yarra Street Drain, Prahran
Table A1.2: Melbourne Water Ancillary Drainage Infrastructure
Hydrographic
monitoring stations
Yarra River at Burnley
Gardiners Creek at Glenferrie Road (Hawthorn)
Gardiners Creek at Gardiner
City of Stonnington Drainage Assets
City of Stonnington drainage asset information was derived from the drainage
asset valuation summary as at June 2010 and the City of Stonnington GIS:
 The City of Stonnington has approximately 315km of drains including
concrete pipes, rectangular section culverts, PVC pipes and ovoid brick
lined drains.
 The City of Stonnington has 13,654 drainage pits.

Appendix B – Roles and Responsibilities
Various agencies and organisations at different levels are directly involved in
managing different aspects of flooding within Victoria, as set out in Table B1
(as at June 2012). Primary and secondary roles in flood management are
outlined in Table B2.
Table B1: Flood Management Roles and Responsibilities
Level Organisation Core role
National
Bureau of Meteorology Flood forecast and warning
Warnings of weather conditions likely to
cause flash flooding
Department of Regional
Australia, Local
Government, Arts and
Sport
Financial assistance for planning, warning
and mitigation initiatives
Australian Emergency
Management
Emergency management planning and
coordination
Department of Human
Services (and
Centrelink)
Financial and other support services for
affected areas
State of Victoria
Victoria Police Regional emergency planning and response
coordination
Victoria State
Emergency Service
Responsible for flood response as well as
assisting council with their Municipal
Emergency Management Planning, can assist
council with education, awareness, warning
systems and emergency management
planning.
Department of Human
Services
Impart expertise in emergency recovery
management, and can assist with the
development of Municipal Emergency
Management Plans and public health sub
plans.
Environment Protection
Authority
Assess environmental impact of flood
emergencies
Department of
Sustainability and
Environment
Has the primary responsibility for the
development of strategies and policy in
relation to flood and stormwater
management at a state-wide level

Department of Planning
and Community
Development
Land use and development policy
Department of Justice State-wide Emergency Management Policy
Financial assistance and grants for those
affected by flooding
Regional
Melbourne Water Primary responsibility for identification of
flood extents, providing flood warning advice
for major waterways, controlling
development in floodplains, providing advice
on flooding to local councils and the
community, developing plans, and
undertaking actions to minimise flooding and
flood damage in the Port Phillip and
Westernport region
VicRoads Drainage for major arterial roads
Local
Municipal Councils
(such as City of
Stonnington)
Manage local urban (street and property) and
upstream drainage
Management of open spaces along waterway
corridors
Manage flooding issues to reduce risks and
impacts
Ensure flood information is available to
inform decisions
Establish and maintain a Planning Scheme
that includes relevant flood provisions
(i.e. administer and enforce planning
provisions and building regulations for flood
affected land)
Implement and maintain local flood warning
systems
Maintain and enhance local flood information
Support community education and awareness
on flood risks
Develop and implement flood emergency
response plans

Table B2: Primary and secondary responsibilities in delivery of flood
management
StateLegislature
StateTreasury
DepartmentofSustainabilityand
Environment
RegionalFloodplainAuthority
LocalCouncil
VICSES
BureauofMeteorology
DepartmentJustice/VicPolice
DepartmentHumanServices
DepartmentofPlanningand
CommunityDevelopment
BuildingCommission
Otherinstitutionsandthe
community
Address legal/institutional
gaps
√ √ √
Analyse and map flood risks √ √ √ √ √
Publish flood risk details √ √ √ √ √
Provide flood intelligence
data
√ √ √ √ √ √
Implement development
controls
√ √ √ √ √
Education and awareness √ √ √ √ √ √
Contingency planning √ √ √ √ √ √ √ √
Flood warnings and alerts √ √ √ √ √ √ √ √
Emergency response √ √ √ √ √ √
Smart urban renewal √ √ √ √ √ √
Runoff reduction √ √ √ √ √ √
Rural levee reform √ √ √

Appendix C – Flood Risk Assessment
The relevant sections of the Melbourne Water Risk Assessment Matrix for the
Stonnington municipality, by catchment, are outlined below identifying the
catchments with medium, high or extreme (‘intolerable’) risk rating (as at
May 2012) (also see Figure 6).
Any future projects to mitigate flood risk will need to be categorised,
discussed and prioritised with due consideration of City of Stonnington and
Melbourne Water priorities, aims, work programs and targets (see
Improvement Plan Action St-8). This process will also need to recognise
residual risks and propose management measures that are likely to include
improved community awareness, flood response planning and preparedness.
Any proposed land use planning or controls to be implemented or investigated
should be included in the program.
Catchment
Name (and
Number)
No of
Commercial/
Industrial
Properties
Flooded
No of
Residential
Properties
Flooded
No.
properties
Total
Flood Risk
Rating
(extreme,
high,
medium,
low)
Murrumbeena
Entire
Catchment9 97
(4850)
1649 1746 Extreme
Murrumbeena
Catchment,
Chadstone Main
Drain (4851)
4 63 67 Extreme
Prahran Main
Drain10 352
(4811)
891 1243 Extreme
Scotchmans
Creek (4860)
82 907 989 Extreme
Tooronga Road11
70
(4823)
312 382 Extreme
Canberra Road
Main Drain
(4816)
0 27 27 High
9
The Murrumbeena catchment in Stonnington includes the Chadstone Main Drain subcatchment and Murrumbeena Drain
subcatchment (downstream of the railway line).
10
The Prahran Main Drain Catchment includes the Prahran Main Drain, Essex Street Main Drain, Williams Road Diversion
Drain and Beatty Avenue Main Drain subcatchments.
11
The Tooronga Road catchment in Stonnington includes the Tooronga Road Main Drain and the Creswick Street Main
Drain subcatchments.

Catchment
Name (and
Number)
No of
Commercial/
Industrial
Properties
Flooded
No of
Residential
Properties
Flooded
No.
properties
Total
Flood Risk
Rating
(extreme,
high,
medium,
low)
Darling Road
(4842)
2 6 8 High
Gardiners Creek
(Glen Iris)
(4840)
0 101 101 High
Gardiners Creek
(Hawthorne)
(4820)
23 112 135 High
Hedgeley Dene
(4841)
0 64 64 High
Yarra Street
Drain, Prahran
(4801)
68 4 72 High
Lara Street Main
Drain (4822)
0 18 18 Medium
Moonga Road
Main Drain
(4821)
0 7 7 Medium
Union Street
Main Drain
(4911)
Not rated
East Malvern
Drain (4844)
Insufficient
data
available to
calculate
Flood Risk
Source: Melbourne Water flood risk matrix, June 2012.

Appendix D – Workshop attendees
This Appendix outlines the two workshops held as part of the preparation of
this Flood Management Plan.
Workshop 1: Stonnington drainage and flood strategy, maintenance,
flooding hot spots, and emergency management coordination
Date: 25 May 2012
Attendees:
Name Position Organisation
Jayantha Balasuriya Asset Management
Development
VicRoads
Erin Davie Team Leader Flood
Strategy
Melbourne Water
James Edmond Infrastructure Planning
and Works Coordinator
City of Stonnington
Drew Flowers Investigations Engineer Melbourne Water
Phil Garner Design Engineer City of Stonnington
John Gowan Asset Planning Engineer,
Team Leader
City of Stonnington
Phil Hughes Principal Consultant/
Project Manager
Halcrow Pacific
Ray Jaspar Regional Manager,
Emergency Management
Victoria State
Emergency Service
Ken MacMahon Senior Hydrographer Melbourne Water
Ewa Madon Environmental Consultant Halcrow Pacific
Katherine O’Connell Coordinator- Roads and
Drains Maintenance
City of Stonnington
Andrew Robison Development Engineer
(Infrastructure Design &
Project Management)
City of Stonnington
Abhiram (Abhi) Sulur Asset Management
Engineer
Melbourne Water
Ade Sutherland Engineer/Flood Modeller Halcrow Pacific

Workshop 2: Flood mapping, planning, Integrated Water Management
and climate change
Date: 1 June 2012
Attendees:
Name Position Organisation
Robin Bishop Investigation and Project
Engineer
Melbourne Water
Erin Davie Team Leader Flood
Strategy
Melbourne Water
James Edmond Infrastructure Planning
and Works Coordinator
City of Stonnington
Drew Flowers Investigations Engineer Melbourne Water
Kerrie Homan Team Leader Land
Development
Melbourne Water
Phil Garner Design Engineer City of Stonnington
John Gowan Asset Planning Engineer,
Team Leader
City of Stonnington
Phil Hughes Principal Consultant/
Project Manager
Halcrow Pacific
Ewa Madon Environmental Consultant Halcrow Pacific
David Portelli Senior Planner City of Stonnington
Andrew Robison Development Engineer
(Infrastructure Design &
Project Management)
City of Stonnington
Ade Sutherland Engineer/Flood Modeller Halcrow Pacific
Jun Yu Senior Statutory Planner City of Stonnington

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