Where is the project at?

    On the 28 August 2018, Council resolved to adopt the Amendment C109 with some changes as recommended by the Independent Panel.  The Amendment has now been submitted to the Minister for Planning for approval.

    This resolution followed receipt of the report of the Independent Panel for Amendment C109 that was held on 5 and 6 February 2018. Panel Report – Manningham Planning Scheme Amendment C109.


    Council considered all 567 submissions to Amendment C109 at its meeting on Tuesday 26 September 2017.

    At that meeting Council resolved to abandon part of Amendment C109 to the Manningham Planning Scheme, known as SB02 and SB03, and to forward the submissions received on LSI0 and SB01 (Melbourne Water controls) to an Independent Panel, which will be appointed by the Minister for Planning.

    Amendment C109 was originally proposed to affect approximately 10,000 properties across Manningham. Of this SB02 was proposed for approximately 3,860 properties and SB03 was proposed for approximately 4,930 properties.

    The Independent Panel was appointed to consider submissions on LSIO and SBO1 in early 2018. All submitters proposed to be affected by the LSIO and SBO1 overlays were provided the opportunity to present to the Independent Panel.

    For more information on Amendment C109, please call our City Strategy Unit on 9840 9453.

    What is an Independent Panel?

    An Independent Panel is appointed by the Minister for Planning.  Such a panel includes experienced planners and/or other professionals with skills relevant to a particular amendment.  Its main role is to review the submissions and provide advice to Council and the Minister about the Amendment and the submissions referred to it.

    Submitters would be given the opportunity to present at a Panel Hearing if they wish.  The Panel Hearing is open to the public and a few months after the hearing is completed, Council would receive a report from the Panel with recommendations to consider.


    How has Council responded to the submissions received?

    Each submission received was individually reviewed and assessed by Council or Melbourne Water officers with assistance from consultants where necessary.

    Where a submitter questioned the modelling affecting their property a further technical review was undertaken against a range of criteria.  These included whether the actual terrain or drainage infrastructure differed from the data used to assess overland stormwater flows and whether the impact on a property was considered minor.  In many cases site visits of individual properties were conducted to better assess the submission against actual site conditions.

    In order to respond to the key issues raised by submitters, Council:

    • Engaged environmental consultants Water Technology to undertake an independent peer review of the methodology used to map the location and extent of the proposed overlays. Water Technology found that the methodology used was sound and robust and complies with best practice.
    • Engaged property advisory firm, Charter Keck Cramer to investigate the impact of the proposed overlays on property values.  Charter Keck Cramer’s Valuation Impact Report found that there would be no impact on the value of properties.  This has been reinforced by previous Panel findings for other flooding amendments in other municipalities in Melbourne.
    • Sought legal advice from Maddocks Lawyers on the process followed so far for Amendment C109.  Maddocks Lawyers has provided detailed legal advice confirming that the correct process has been followed for this amendment and that using a planning scheme amendment process to introduce the overlays is by far the most effective and transparent option.
    • Sought advice on the impact the proposed overlays could have on insurance premiums.  The Insurance Council of Australia has advised Melbourne Water that most insurance policies provide coverage for storm damage. Previous Panels have consistently determined that the potential impact on insurance premiums is not a matter that should have any bearing on the application of an LSIO (Land Subject to Inundation Overlay) or SBO (Special Building Overlay).

    Further detailed discussion responding to each of these matters and responses to each submission can be found in the Council report on Amendment C109 available at www.manningham.vic.gov.au/council-meeting-26-september-2017

    Were the recorded impacts of the 29 December 2016 storm event consistent with the proposed Amendment C109 overlays?

    The storm event of 29 December 2016 resulted in reports of flash flooding of homes at 16 properties across Bulleen, Templestowe, Doncaster, Doncaster East and Warrandyte, as well as a range of other associated requests for investigation and maintenance services.  While only 16 property owners have reported flooding of homes, officer experience is that in many cases, residents do not report flooding.

    Analysis of the flooding circumstances for the 16 properties indicated that eight of the properties coincide with proposed SBO2 or SBO3 overlays.

    Field investigations revealed that in all other cases, while the properties are not proposed to be impacted by the new overlays, Council drains and in some cases private drains at each property required maintenance, for example from tree root invasion from privately owned trees. The flood mapping undertaken assumes that all Council drains are operational and not blocked.

    The flood mapping undertaken in support of the proposed Planning Scheme Amendment C109 is based on a one in 100 year storm event (or has a 1 per cent chance of occurring in any year) and represents a worst case scenario storm event occurring across all catchments simultaneously. Actual storms, such as the 29 December event, will typically vary in intensity, extent and duration across different areas of the municipality.

    A consultant was engaged to assess the average interval of the 29 December storm as it impacted Manningham, based on Melbourne Water rainfall gauge data at four locations across the municipality. The results indicate that the average interval of this storm ranged between a one in 33 year event and a one in 63 year event at three of the four locations. The average interval estimated at the former Eastern Golf Course gauge was however in excess of a one in 100 year event.

    Based on field investigations and analysis, it is considered that the major impacts of the storm event of 29 December 2016 are not directly comparable with the flood overlays due to the fact that the average interval of the event across Manningham was less than a one in 100 year event.

    It should be noted that the modelling is based on a critical one in 100 year storm, which not all 100 year storms will match as they may have a shorter duration.

    The results of the independent peer review of the flood modelling by Water Technology supported the approach taken.

    The storm event of 29 December 2016 resulted in reports of flash flooding of homes at 16 properties across Bulleen, Templestowe, Doncaster, Doncaster East and Warrandyte, as well as a range of other associated requests for investigation and maintenance services. While only 16 property owners have reported flooding of homes, officer experience is that in many cases, residents do not report flooding.

    Analysis of the flooding circumstances for the 16 properties indicated that eight of the properties coincide with proposed SBO2 or SBO3 overlays.
    Field investigations revealed that in all other cases, while the properties are not proposed to be impacted by the new overlays, Council drains and in some cases private drains at each property required maintenance, for example from tree root invasion from privately owned trees. The flood mapping undertaken assumes that all Council drains are operational and not blocked.

    The flood mapping undertaken in support of the proposed Planning Scheme Amendment C109 is based on a one in 100 year storm event (or has a 1 per cent chance of occurring in any year) and represents a worst case scenario storm event occurring across all catchments simultaneously. Actual storms, such as the 29 December event, will typically vary in intensity, extent and duration across different areas of the municipality.

    A consultant was engaged to assess the average interval of the 29 December storm as it impacted Manningham, based on Melbourne Water rainfall gauge data at four locations across the municipality. The results indicate that the average interval of this storm ranged between a one in 33 year event and a one in 63 year event at three of the four locations. The average interval estimated at the former Eastern Golf Course gauge was however in excess of a one in 100 year event.

    Based on field investigations and analysis, it is considered that the major impacts of the storm event of 29 December 2016 are not directly comparable with the flood overlays due to the fact that the average interval of the event across Manningham was less than a one in 100 year event.
    It should be noted that the modelling is based on a critical one in 100 year storm, which not all 100 year storms will match as they may have a shorter duration.

    The results of the independent peer review of the flood modelling by Water Technology supported the approach taken.

    Why is Council proposing Amendment C109?

    In July 2005, the Victorian Auditor General recommended that Melbourne Water and councils carry out flood mapping and include the results in local planning schemes to provide a higher level of flood protection for new development across Victoria. As a result Melbourne Water took on the role of co-ordinating flood mapping across the metropolitan area.

    Accurate flood mapping is considered to be a critical foundation for the management of flood risk. As part of the adoption of the joint Manningham Flood Management Plan with Melbourne Water in 2011, Council committed to flood mapping of the municipality.

    Manningham Council is not the first Council to propose and/or implement changes to its planning overlays to address updated mapping of overland stormwater flows associated with extreme rainfall. Similar processes to Amendment C109 have been implemented at more than 20 councils across Victoria, including Port Phillip, Yarra, Stonnington, Banyule, Glen Eira and Moonee Valley councils

    What work was completed to plan for Amendment C109?

    In response to the state level recommendation, together with Melbourne Water, Manningham Council completed a detailed analysis and mapping of the majority of the stormwater catchments in Manningham, which included assessing the overland stormwater flows associated with major storm events.

    This work has been jointly funded with Melbourne Water and the Office of the Emergency Services Commissioner, and the methodology followed industry best practice, which was also used by Melbourne Water and other councils.

    In response to this new flood mapping information Council is proposing to amend the Manningham Planning Scheme to update the overlays currently in the Manningham Planning Scheme, including the Special Building Overlay (SBO) and Land Subject to Inundation Overlay (LSIO), to better identify areas that may be affected by storm overland flows during extreme rainfall events and flooding from creeks and waterways.

    To include this new information into the Manningham Planning Scheme, Council must make a formal amendment (known as Amendment C109) to the planning scheme. 

    What is the Land Subject to Inundation Overlay and the Special Building Overlay?

    The Land Subject to Inundation Overlay (LSIO) applies to land affected by flooding associated with waterways and open drainage systems managed by Melbourne Water. These areas are commonly known as floodplains.

    The Special Building Overlay (SBO) identifies areas prone to overland stormwater runoff associated with main drains exceeding their capacity in a severe storm event, which has a 1 per cent chance of occurring each year. The SBO is largely associated with flash flooding.

    The existing SBO and LSIO have been in place in the Manningham Planning Scheme for many years and the purpose of these overlays is to set appropriate conditions and floor levels for development to minimise any stormwater risk to developments and surrounding properties. These overlays require a planning permit for buildings and works.

    Amendment C109 proposes to update the location and extent of these overlays in response to new information.

    The Land Subject to Inundation Overlay (LSIO) applies to land affected by flooding associated with waterways and open drainage systems managed by Melbourne Water. These areas are commonly known as floodplains.

    The Special Building Overlay (SBO) identifies areas prone to overland stormwater runoff associated with local or main drains exceeding their capacity in a severe storm event, which has a 1 per cent chance of occurring each year. The SBO is largely associated with flash flooding.

    The existing SBO and LSIO have been in place in the Manningham Planning Scheme for many years and the purpose of these overlays is to set appropriate conditions and floor levels for development to minimise any stormwater risk to developments and surrounding properties. These overlays require a planning permit for buildings and works.

    Amendment C109 proposes to update the location and extent of these overlays in response to new information.


FAQ Archives

    I’m thinking of doing some development on my property, what should I do?

    Council’s Statutory Planning Unit assesses planning applications for residential developments. If you are thinking of making a planning application, discuss your proposal with us by calling 9840 9333.

    It would be helpful to examine SBO and LSIO maps and identify the parts of your property that are affected.

    For more information on the planning permit process, visit www.manningham.vic.gov.au/application-process


    When will the proposed Special Building Overlay and Land Subject to Inundation Overlay come into effect?

    The process to amend the planning scheme to include the SBO and LSIO commenced in November 2015 with the exhibition of Amendment C109.

    All property owners affected by the amendment were contacted directly during the exhibition period and were provided an opportunity to make a submission.

    Council considered all submissions received and made a decision on how to progress the amendment on the 26 September 2017. Following a panel hearing, If the amendment is approved by Council, it will be forwarded to the Victorian Minister for Planning for approval.

    The SBO and LSIO would come into effect once the amendment has been approved by Council and the Minister for Planning.


    What should I do if the proposed Special Building Overlay or Land Subject to Inundation Overlay affects my property?

    Examine the Special Building Overlay and Land Subject to Inundation Overlay maps and identify the parts of your property that are affected.

    Once the SBO and LSIO have been enacted you may be required to obtain a planning permit for development within the shaded areas. The SBO and LSIO provisions include various exemptions, so before preparing any planning permit application, first check to see if your proposal is exempt.

    Please note that other, separate provisions in the Manningham Planning Scheme (that do not relate to the SBO or the LSIO) may trigger the need for a planning permit for your proposal. Also talk to a registered building surveyor to see if your proposal needs a building permit.

    If you are not planning any new buildings or works, you should take note of the overland stormwater flow paths that have been identified through your property and do what you can to maintain a clear path for any flows that could occur. You should also avoid placing items that may be damaged by stormwater within these flow paths.


    In addition to the SBO and LSIO, what is Council doing to reduce flooding risks?

    Flooding is a natural hazard in Victoria’s river systems and natural and constructed drainage systems.

    Understanding flood behaviour enables Council to assess the likely impacts and costs of flooding. It also enables us to assess the benefits of different options for managing the community’s exposure to flood risk.

    There are no quick fixes in reducing the damage caused by flooding. Two centuries of development on flood plains and low lying areas mean that legacy issues will remain for a very long time.

    To assist in our understanding of the flood risk in the City of Manningham, together with Melbourne Water we have undertaken extensive flood modelling of the using the latest land and rainfall data and computer technology. We are using this data as part of the amendment process to update the SBO and LSIO in the Manningham Planning Scheme to reduce the risk flooding in high risk areas. This information is also being used to investigate a range of mitigation options in the smaller catchments (Council drainage systems).

    We also have an ongoing proactive and planned maintenance program of drainage pit cleaning to reduce nuisance flooding in high risk areas.

    Council works closely with Melbourne Water, the State Emergency Service, VicRoads and other government agencies on our flood prevention, response, recovery and mitigation activities.

    Further to the above, on 26 September 2017 Council resolved as follows:

    That Council:
    • use the knowledge of drainage network improvements needed, gained through the C109 amendment process to inform the prioritisation of drainage maintenance and upgrades in the next 4 years.
    • proceeds with the investment of at least $10.8M in drainage  works over the next 4 years in our current budget, and prepares a plan to increase that investment for the next budget.
    • completes the upgrade to the Asset Management system to better enable efficient planning and management of drainage assets.

    What are the proposed changes to the referral process?

    When planning permit applications are received, referral authority comments will be sought as follows:

    ·  In SBO1 and LSIO areas – applications will be forwarded to Melbourne Water for review, and as a Determining Referral Authority under Clause 66.03 of the Manningham Planning Scheme Council is bound by the decision that Melbourne Water makes.

    Is compensation payable?

    Melbourne Water has provided the following advice in relation to compensation:

    The Planning and Environment Act 1987 clearly sets out the circumstances where compensation is payable and is essentially limited to where land is reserved or required for a public purpose or where access is to be denied by the closure of a public road. It does not cover situations where controls such as the SBO/LSIO are imposed.

    There are sound public policy reasons why the application of these sorts of overlays are not incorporated into that section, namely, the overlay is merely seeking to identify a particular characteristic of land existing at the time of the application of the overlay and ensure that future development is consistent with strategic planning for the area as a whole and the health and safety of current and future occupants of the development.

    The overlay does not cause or change the likelihood of flooding. Overland flows are attributable to the limitations of the capacity of the underground drainage that was constructed in accordance with the requirements of the time. While the overlay may identify the drainage conditions of the land, there is, appropriately, clear legislative indemnification from any claims arising out of the identification of land liable to flooding.


    Will my insurance cover flood damage?

    Melbourne Water has provided the following advice in relation insurance coverage:

    The Insurance Council of Australia has advised Melbourne Water that most insurance policies provide coverage for storm damage, include cover for damages resulting from overland flows. However, this needs to be confirmed by the household’s individual insurer. Melbourne Water is providing information to the Insurance Council of Australia to improve the availability of flood insurance policies.

    Households affected by the Special Building Overlay and LSIO, who were not previously aware of the drainage characteristics of their land, now have the opportunity to check their policy coverage and seek alternative insurance where this is not considered adequate


    Will this proposal affect the value of my land?

    There are many factors that influence land value including location, amenity, recent sales results and property improvements. It is important to note that the potential overland stormwater flow paths identified in the SBO and LSIO are due to the topography of your land and the surrounding neighbourhood. This has not changed and the SBO and LSIO identifies and quantifies the risk that was always present. Amending the Manningham Planning Scheme to include the SBO and LSIO will help Council and property owners better manage risk through appropriate development.

    Melbourne Water has provided the following advice in relation to the impact of the SBO on property values. This response can also be applied to properties affected by the LSIO:

    It is important to note that the Special Building Overlay does not cause or change the likelihood of flooding, but recognises the existing condition of land.

    The Special Building Overlay will not be described on title but will be included in addition to the information available to the public through property information statements issued by the retail water companies, such as Yarra Valley Water under Section 239G of the Melbourne and Metropolitan Board of Works Act 1958. Like information will be also be included in planning certificates contained within Vendor’s Statements issued under Section 32 of the Sale of Land Act 1962.

    The value of any property is determined by the complex interplay of many different factors such as location, streetscape and amenity, and it is difficult to assign what effect, if any, the identification of land as liable to overland flows may have on the value of a property. Properties are not uniformly affected by overland flows and this may depend upon the frequency or severity of flooding, any implications for redevelopment, historical flood events, etc.

    Planning scheme amendments to introduce a SBO have been exhibited in 25 metropolitan planning schemes. In no case has there been a demonstrated example of devaluation as a consequence of the overlay although in all cases where a Panel has been asked to consider and report on submissions opposing the application of such an overlay, the issue of property devaluation has been considered and rejected by the Panel.


    Will this information go on a Section 32 if I decide to sell my property?

    When selling a property, a Section 32 Vendor Statement is provided by the seller of the property to a potential purchaser.

    The Statement provides certain information to a potential purchaser before a contract of sale is signed, and includes a Planning Certificate. The Planning Certificate identifies the existing planning scheme controls that apply to the land such as the zoning and overlays. It also identifies if there are any planning scheme amendments that propose to alter the planning scheme controls on a property. While Amendment C109 is still being considered, it will be identified under ‘Proposed Planning Scheme Amendments’ towards the bottom of the Planning Certificate. 


    Will this information go on my title?

    No. Planning scheme controls, such as zoning or overlays information, are not registered on the titles of properties. Therefore an LSIO or SBO, whether they are existing or proposed, will not be registered on the title of a property.


    Who calculates and has information on the flood levels?

    Melbourne Water is the responsible drainage authority for their SBO1 and LSIO areas and together with Council have undertaken updated modelling to calculate flood levels.

    Melbourne Water has the flood level information for the LSIO and SBO1 areas, including flood levels for proposed new areas added to the SBO and LSIO as part of Amendment C109.

    Flood level data for the one in 100 year flood event is updated by Melbourne Water well in advance of any planning scheme amendment process. This ensures that the flood information is up to date and available from service providers, Landata and SAI Global, and via Property Information Statements included in Section 32 statements. Advice is available by calling Melbourne Water on 9679 7517 or emailing land.development@melbournewater.com.au


    What if the SBO or LSIO only partially covers my property?

    The requirements in the SBO and LSIO only apply to the parts of the property that are covered by the SBO and LSIO. For example, if the SBO only covers the front one metre of a property then a planning permit will only be required by the SBO for any buildings and works proposed within the front one metre of the property.

    Any proposed buildings and works should be referred to Melbourne Water for initial comment and advice in SBO1 and LSIO areas.

    Many properties are also covered by other overlays such as the Development and Design Overlays, Heritage Overlay or Environmentally Significant Overlay, or there may be separate requirements in the zone (e.g. General Residential Zone) – meaning that there still may be the need for a planning permit to construct a building, construct or carry out works on your property.


    Is an application in the SBO and LSIO eligible for VicSmart?

    Yes. VicSmart is a simple and fast assessment process for straightforward planning permit applications. It was introduced to the Victoria Planning Provisions and all planning schemes on 19 September 2014.

    Planning applications to construct a building, construct or carry out works on properties with an SBO and LSIO are eligible for the streamlined VicSmart process – if it is the only requirement for a permit or the other triggers for the need for a permit (i.e. in other zones, overlays or particular provisions) are also eligible for VicSmart.


    Do I need a planning permit in SBO and LSIO areas?

    Yes, a planning permit is required to construct a building, construct or carry out works for areas with an SBO and LSIO. This can include things such as road works, swimming pools, fences and decks, which may not normally require a planning permit. This is designed to allow Melbourne Water and Council to assess the impact a development would have on the passage of overland flow or flooding.

    My property is included in the proposed SBO and LSIO. What does this mean?

    The proposed overlays (SBO and LSIO) identify areas where overland stormwater flows and exceeds a certain depth and/or may result in a hazard.

    Both overlays (the SBO and LSIO) require planning permits for development and the LSIO and SBO1 require referral to Melbourne Water to ensure that floor levels are set above the mapped 100 year flood levels in the affected areas.

    Please note that letters were also sent to 200 properties that were identified as no longer being subject to flooding. For these properties it is proposed that the existing SBO or LSIO be removed.


    How can my property be affected if it is on a hill?

    If an overlay is proposed to your property, it doesn’t necessarily mean that flooding will rise up from the existing drainage network.

    The computer modelling that Council and Melbourne Water undertook simulated a rainfall from a severe storm event. As the extreme rainfall falls on high points (e.g. high on a hill), it then starts travelling down to low points. This is known as overland flow.

    The computer modelling and mapping has identified that sometimes properties located on a hill that may be affected by overland flow (over a certain depth) across their property.


    I have never experienced overland stormwater flows on my property. Why then is my property in the Special Building Overlay or Land Subject to Inundation Overlay?

    The SBO and LSIO maps are based on the forecasted overland stormwater flows associated with a one in 100 year storm event, meaning that there is a 1 per cent chance that such an event could occur in any year.

    In many cases, the one in 100 year stormwater event may only have water at certain depths for a short period of time, but it is capable of causing damage.

    It cannot be assumed that flooding has not previously or will not occur on any given property simply because there are no recollections of flooding at that property. 


    How was the modelling and mapping undertaken as part of the stormwater catchment analysis?

    A computer modelling program is used to prepare the stormwater catchment analysis. In order to understand where the overland flows and flooding might occur in a severe storm event, the following information is put into the computer modelling program:

    ·  Contours of the land (topography)

    ·  The type of surface

    ·  The location of drainage pipes and channels

    ·  The size of drainage pipes and channels (how much capacity they have)

    ·  The location of pits (where stormwater can get into the drains)

    A rainfall associated with a one in 100 year storm event is simulated, and the modelling program can determine where stormwater could flow from a high point to a low point (where the drainage pipes are), where flooding may occur near the drainage network, and where the overland flows might exceed a certain depth.

    The mapping used to inform the overlays reflects the modelled overland flows or flooding, where they exceed a certain depth. 


    How did Council identify overland stormwater paths?

    A detailed stormwater catchment analysis was commissioned to show the effect of one in 100 year rainfall on Council’s drainage network.

    This study identified overland stormwater flow paths associated with such an event occurring in Manningham.


    What is Council proposing to change with the existing Special Building Overlay?

    The proposed SBO is now titled SBO1 which clarifies that a referral to Melbourne Water is needed and that the control relates to Melbourne Water main drains.

    Is there already a Special Building Overlay and Land Subject to Inundation Overlay in the Manningham Planning Scheme?

    Yes, the existing SBO was introduced into the Manningham Planning Scheme by Melbourne Water in 2003 and covers overland stormwater flow paths associated with Melbourne Water drains. The LSIO was also introduced into the Manningham Planning Scheme in 2003 with Melbourne Water being the responsible drainage authority for development applications. 


    Who is responsible for stormwater drainage and management of severe storm impacts in Manningham?

    Melbourne Water is the Catchment Management Authority for Greater Melbourne. Melbourne Water has responsibility for the parts of the drainage system which have large catchment areas (greater than 60 hectares). The remaining catchments including the majority of the drains, pits and pipes within Manningham are managed by Council.

    Today, all new developing suburbs consider flood risk and include measures to reduce the impacts, so that:

    ·  Underground drainage systems are generally designed to cope with most frequent storms – those with a 20 per cent chance of occurring in a year

    ·  Once the drainage system is full, planned overland flow paths like roads, channels or open spaces carry the excess floodwater safely to rivers or creeks. This ensures properties do not flood during a one in 100 year storm event.

    Manningham Council is incrementally upgrading older drainage infrastructure, however we cannot build a drainage system that can cope with all floods. We can ensure new buildings and works are constructed to reduce the risk of flooding in areas that have been identified as being at risk of flooding in extreme rainfall. We can also make sure new developments are better planned, and work to minimise flood risks and impacts.

    All drainage systems, including Melbourne Water’s, are designed to carry normal stormwater flows. They are not designed to manage the flows resulting from extreme or severe storm events. Council and Melbourne Water, however, are required to assess and manage stormwater overland flows that may result from extreme or severe events.


    Why does flooding occur?

    Large cities like Melbourne will always experience some type of flooding – it is an inevitable part of our weather cycle.

    Most flooding problems occur because older suburbs (like those in Manningham) were built using different design standards to those that apply today. Suburbs developed before the mid to late 1970s did not need to plan for how water would flow over land when the drainage system was full. This means that the excess floodwater still follows natural valleys and drainage paths, which sometimes run through properties and may affect houses.


    Who is responsible for drainage infrastructure?

    Melbourne Water and councils share responsibility for most of Melbourne’s drainage system:

    ·  Melbourne Water installs and maintains the regional drainage network – large drains and stormwater infrastructure connecting with rivers, creeks and bays

    ·  Local councils manage the local drainage network, including street gutters and drains

    ·  Individual property owners are responsible for drainage systems on their property such as roof gutters, downpipes and pipelines, which generally connect to council drainage systems.


    How does the drainage system work?

    When it rains, some water naturally seeps into the ground. The rest makes its way through drainage systems, into rivers and creeks and eventually into the bays, or directly to the bays through stormwater beach outlets.

    In areas with houses, shops and roads, we need to create alternative ways for this water to drain away. During heavy rain and storms, large amounts of water can build up quickly and without adequate drainage this water flows towards low-lying land and can cause flooding, damage and safety risks.

    For this reason, Melbourne Water works with local councils to provide a drainage system that safely carries stormwater away from built-up areas and into rivers and creeks.

    Here’s how it works:

    1.  Stormwater runs off Melbourne’s properties and their roofs through house gutters and downpipes, and into residential drains

    2.  Residential drains connect to streets and roads or council drains

    3.  Council drains connect to Melbourne Water’s regional drains

    4.  Regional drains direct water into the nearest river or creek or directly to Port Phillip Bay

    5.  Rivers and creeks eventually empty into Port Phillip Bay or Western Port Bay


    What is a one in 100 year storm event?

    Storms are classified using historical rainfall data and statistical probability. A one in 100 year storm event is a storm with characteristics that are only expected to occur on average once every 100 years (therefore being a 1 per cent chance).


    Where does the amendment apply?

    The revisions to the overlays (SBO and LSIO) across Manningham will result in:

    ·  Approximately 1,100 properties will be included or retained in the SBO and LSIO

    ·  Approximately 200 properties having the SBO or LSIO removed.

    Why prepare the amendment?

    In July 2005, the Victorian Auditor General recommended that Councils carry out flood mapping and include the results in their planning schemes to provide a higher level of flood protection,

    Melbourne Water and Council are the responsible drainage authorities for main and local drains respectively and together have recently undertaken updated modelling of severe storm events for Manningham. Improved computer technology was used along with the latest land and rainfall data to more accurately reflect where overland stormwater flows may occur in extreme rainfall. This information is more accurate than the existing modelling available.

    In order to provide properties with a greater level of protection against potential storm events, Council and Melbourne Water are proposing to change the planning overlays to reflect the modelling that was undertaken.

    The overlays (known as SBO and LSIO) will ultimately assist the community and Council to achieve appropriate outcomes in the planning process, and ensure that any new developments are built appropriately in areas where there could potentially be storm damage in the future.

    The amendment process makes information on the proposed overlays and updated flood mapping available to:

    ·  Current property owners, particularly those intending to develop their land

    ·  The general community, to ensure there is greater awareness and management of stormwater events

    ·  Future purchasers

    ·  Council

    ·  Melbourne Water. 


    When was the exhibition/consultation?

    Exhibition of Amendment C109 formally commenced on Thursday 12 November 2015, and the closing date for submissions was Thursday 24 December 2015.


    Where can I get more information?

    All information, including documentation, planning scheme maps and technical reports, about Amendment C109 is available on the Your Say Manningham website, www.yoursaymanningham.com.au/Amendment-C109.

    For general enquiries, please call Council’s Strategic Planning Unit on 9840 9129 or visit the Planning Counter at the Manningham Civic Centre, 699 Doncaster Road, Doncaster.

    This amendment relates to revised planning overlays, known as either a Special Building Overlay (SBO) or a Land Subject to Inundation Overlay (LSIO). 

    Melbourne Water is the responsible drainage authority that have been involved along with Council in the assessment of these proposed overlays.

    For technical information about:

    ·  SBO1 and the LSIO affected areas, please call Melbourne Water on 9679 7517 or email land.development@melbournewater.com.au