Agenda of Flood Management Advisory Committee

Flood Management Advisory Committee Meeting

24 July 2024

Minutes of the Flood Risk Management Advisory Committee Meeting held on 29 February 2024 on Microsoft Teams

Meeting commenced at 2:00 PM

Directorate Name	Infrastructure
Date / Time	29 February 2024 - 2:00 PM
Venue	Microsoft Teams
Chairperson	Councillor Mat Howard
Voting Attendees	Clr Mat Howard	Clr Marghanita Da Cruz	Lois Gray (CR)
Voting Attendees	Shad Wall (CR)	Alexander Bailey (SES)	Michael Carney (SES)
Non – Voting Technical Advisory Attendees	Ryann Midei (IWC)	David Paton (IWC)	James Ogg (IWC)
	Rafaah Georges (IWC)	Sadeq Zaman (DCCEEW)	Martin Griffin (Stantec)
	Alireza Pouya (Stantec)
Observers	Klaus Neuscheler (SES)	Helen Slater (SES)	Robert Baker (SES)
	Anson Chang (Stantec)	Habba Rahimi (Stantec)	Jogo Jayanti (City of Sydney)
	Well Yum (City of Sydney)	Aaron Biffin (Bayside Council)	Christy Li (IWC)
Apologies	David Grasby (Sydney Water)

1. 1. Acknowledgement Of Country – Clr Howard

I acknowledge that we are meeting on the land of the Gadigal and Wangal people of the Eora Nation and pay my respects to the elders past and present and I extend that respect and acknowledgement to any Aboriginal people who are here with us today.

2. Disclosures of Interest

Nil.

3. Confirmation of Minutes of 27 July 2023 Flood Management Advisory Committee

That the Minutes of the Flood Risk Management Advisory Committee Meeting held on 27 July 2023 be confirmed.

4. Review of Flood Management Advisory Committee Terms of Reference

SUMMARY

An amended Terms of Reference was presented to the committee incorporating a review of NSW legislation and flood management guidance manuals, current membership, meeting schedule, consistency with other Flood Management Committees, and consistency with similar committees of Inner West Council.

OFFICERS RECOMMENDATION

That the Flood Management Advisory Committee endorse the updated Terms of Reference.

DISCUSSION

Councillor Da Cruz noted that the terms of reference only include Transport for NSW Roads, which leaves out Maritime and other public transport. Councillor Howard questioned whether specifying Transport for NSW will provide them with more capacity to determine who would be best to come address certain matters. Council Officers advised that while Transport for NSW is a large organisation with many units of responsibilities, the Roads unit are the third largest stakeholder in asset ownership in terms of pipes within Inner West Council and are the most affected by proposals to upgrade those networks and more impacted by flooding through road closures and evacuation routes. which would be relevant to flooding, however accepted that the Terms of Reference include Transport for NSW to provide greater flexibility to invite specific teams with greater interest in a particular item.

Councillor Da Cruz questioned whether we should have a representative from Planning and Infrastructure. Council Officers advised that the NSW Department of Climate Change, Energy, Environment and Water are the experts for flooding in the NSW Government and receive referrals from the Department of Planning, Housing and Infrastructure.

Councillor Da Cruz queried whether Council has communication channels with SSROC noting a recent grant they received from to do resilience planning. Council Officers advised that the resilience grant was about the preservation of waste services to natural disasters, rather than specific flood resilience. SSROC operates to serve its member Councils and Council interacts with them though other avenues.

Councillor Howard queried how many of the local community representative positions were currently filled and the recruitment process for vacancies. Council Officers advised that due to recent resignations there are 2 of the possible 8 positions filled. The terms of reference specify that a new expression of interest is not undertaken within 6 months of a Council Elections. A new expression of interest process will be undertaken following Council elections.

Councillor Da Cruz queried whether Council could investigate having a pool of community members to select from when items are relevant to their catchment as it may provide greater local knowledge as the current commitment may discourage people from joining. Alexander Bailey expressed that while the representatives may come from a catchment the purpose of the committee was not on a local flooding environment, but the general overall changes that affect the whole community. Councillor Howard noted that what happens in one part of the community does impact what's happening in the others, particularly regarding hydrology and flood impacts. Therefore, having representation that reflects and reports back to the larger community helps plays a part in the success of the committee. Council Officers noted that this was part of the reason that the scope for possible community representatives was broadened. The Committee supported the proposed community representative selection criteria.

COMMITTEE RECOMMENDATION

That the Flood Management Advisory Committee endorse the updated Terms of Reference subject to replacing Transport for NSW Roads with Transport for NSW.

For Motion: Unanimous

5. Future Flood Education

SUMMARY

Council resolved on the 12 September 2023:

C0923(1) Item 12 – 3. That a future flood education strategy for the wider local government area be developed and presented to the Flood Management Advisory Committee.

Council Officers presented a report outlining the responsibilities for Flood Education and ways in which Council can support these efforts. Community engagement is an integral part of the flood risk management process as it raises overall community flood awareness and supports community response strategies. The NSW State Emergency Service (SES) acts as the lead agency under the Emergency Management framework for flooding and flood management, including ongoing community awareness and education, informing the community on how to prepare for and act in response to a flood threat, and assisting with the issuance of flood warnings.

A proposed shortlist of actions and activities was presented to the committee with short-, medium- and long-term timeframes, as outlined in the report to the committee.

OFFICERS RECOMMENDATION

That the Flood Management Advisory Committee support the schedule of actions to be taken to facilitate flood education within Inner West Council.

DISCUSSION

Lois Gray suggested that when a Flood Plan document is adopted by Council, that real estate agents in the LGA be informed. Councillor Howard agreed to Lois’ suggestion and proposed an amendment to the recommendation that Council develop a flier or postcard regarding flooding and relevant services in the local area including the SES that can be made available through customer service centres, libraries and be made available to local real estate or rental agencies for new residents to the local community.

Alexander Bailey noted that the SES would look forward to a closer liaison between Ashfield, Leichhardt and Council in terms of presentations to the community and what the planning indicates. Alexander noted that through the indication of what state emergency services can respond to, local communities can be become more resilient by becoming better informed, allowing them to prepare ahead and watch the warning signs.

Councillor Howard questioned whether Council will be working with our local SES commands to deliver some of that information. Council Officers responded that Council will be doing drop-in sessions where the SES will be invited to those sessions to engage with the community such as when Council did the Hawthorn Canal, Dot Rd Canal and Marrickville Valley engagement. Councillor Howard proposed that the Committee note that the proposed drop-in sessions will be held with our local SES units.

Robert Baker queried whether the proposed signage would include potential evacuation routes. Council Officers responded that there is currently no specific schedule of signage yet. Councillor Howard proposed that in the public signage section, Council to investigate the role of specific evacuation signage and how that might compliment other public education programs Council is undertaking.

Councillor Da Cruz questioned whether public education programs need to be aimed at different groups visiting our community. Council Officers responded that a program that accounts for all visitors, the scope of a campaign can become unmanageably broad. However, by engaging the local community first and supporting their preparations and awareness, it would reduce the burden on our SES partners in a flood event.

Councillor Da Cruz questioned whether Council’s education program identify the community groups who are at risk because they are located on the foreshore. Councillor Howard suggested we were to add to the recommendation that we increase public engagement through working with community organisations located on the foreshore who may be potentially at a higher risk of flooding.

Councillor Howard proposed an amended motion to include the development of a flier regarding flooding and relevant services in the local area to be provided Council’s Customer Service Centres and to real estate agents to inform new and existing residents of the local community. The Committee debated the purpose and scope of such a communication piece.

Robert Baker raised concerns to not being able to tell when roads are closed due to flooding. Robert Baker suggested that Council investigate how Council can put road closure information on the Councils website, noting that some Councils have arrangements with Live Traffic to get local road information up onto Live Traffic. David Paton advised that Council is already investigating ways to enact such an arrangement to allow Council staff to upload information to the Live Traffic website.

Councillor Howard moved an amended recommendation to address the Committees concerns.

COMMITTEE RECOMMENDATION

1. That the Flood Management Advisory Committee support the schedule of actions to be taken to facilitate flood education within Inner West Council.

2. That Council develop communications regarding flooding and relevant services in the local area including the SES that can be made available through customer service centres, libraries and be made available to local real estate or rental agencies for new residents to the local community.

3. That Council better support and promote the activities of the SES, including in our local newsletter.

4. That in the development of the Flood Information Hub, Council work to make emergency information for accessible and visible, that Council investigates the reporting of local road closure information.

5. That the proposed information sessions undertaken with the Alexandra Canal Flood Risk Management Study and Plan and Johnstons Creek Whites Creek Flood Risk Management Study and Plan be undertaken with SES Officers.

6. That Council investigate the publication of evacuation routes among consideration of public signage.

7. That Council engage directly with community groups on the foreshore impacted by flooding.

For Motion: Unanimous

6. Inner West Local Flood Plan

SUMMARY

This report details the amendments to the Inner West Emergency Plan, adopted in 2016, particularly the Volume 1 of the Flood Emergency Sub Plan. It was noted that these amendments have been led by the NSW SES Metro Zone, following the adoption of the Australian Warning System and changes to NSW Government departments and agencies.

Helen Slater from NSW SES Metro Zone was invited to providing an overview of the Local Flood Plans for the Inner West. Volume 1 addresses the roles and responsibilities in flood emergency management as well as the range of strategies available to manage an emergency. The updates impact the Warning Categories and NSW Government departments and agencies described in Volume 1.

NSW SES continues to progress the development Volume 2 and 3, which describes the hazard and risk specific to the Inner West and outline how SES will manage these specific floods the triggers used to enact the various strategies in the plan.

OFFICERS RECOMMENDATION

That the Flood Management Advisory Committee endorse the amended Inner West Council Flood Emergency Sub Plan

DISCUSSION

The Committee members supported the Council Officers recommendation.

COMMITTEE RECOMMENDATION

That the Flood Management Advisory Committee endorse the amended Inner West Council Flood Emergency Sub Plan.

For Motion: Unanimous

7. Presentation of Alexandra Canal Flood Risk Management Study & Plan and Johnstons Creek / Whites Creek Flood Risk Management Study& Plan (Confidential)

SUMMARY

The Alexandra Canal Flood Risk Management Study and Plan and Johnstons Creek & Whites Creek Flood Risk Management Study and Plan were presented to the Committee.

Martin Griffin, representing Council’s technical consultant Stantec was invited to provide a presentation detailing the progress to date, the risks affecting the two catchments and potential damages, the overall review of options and the multicriteria analysis that was used to develop the final prioritisation listings that are presented in the Draft Flood Risk Management Studies and Plans for the two catchments.

The initial assessment included 21 options for Alexandra Canal, 9 options for Whites Creek and 28 options for Johnstons Creek. The final implementation plan includes

- 9 options for Alexandra Canal (4 flood management options, 1 property management option and 4 emergency management options) with the 4 high priority options totalling $1.3 million

- 17 options for Johnstons Creek and Whites Creek (11 flood management options, 1 property management option and 4 emergency management options) with the 7 high priority options totalling $5.9 million.

Subject to the endorsement of the Committee, Council Officers will take the Studies and Plans to Council in April for community engagement in May. The community engagement would incorporate comments and feedback from the affected residents about the proposed options, which could result in amended prioritisation if the community expressed strong desire for particular outcomes.

OFFICERS RECOMMENDATION

1. That the Flood Management Advisory Committee endorse the public exhibition of the Alexandra Canal Flood Risk Management Study and Plan.

2. That the Flood Management Advisory Committee endorse the public exhibition of the Johnstons Creek and Whites Creek Flood Risk Management Study and Plan.

DISCUSSION

The Committee members supported the Council Officers recommendation.

COMMITTEE RECOMMENDATION

1. That the Flood Management Advisory Committee endorse the public exhibition of the Alexandra Canal Flood Risk Management Study and Plan.

2. That the Flood Management Advisory Committee endorse the public exhibition of the Johnstons Creek and Whites Creek Flood Risk Management Study and Plan

For Motion: Unanimous

8.General Business

Update on Council Resolutions:

Council Officers advised that the letters for the community member affected by Hawthorn Canal and Dot Road Canal have been distributed.

Update on Flood Mitigation Programming

Council Officers advised this was touched on in the July Flood Advisory Committee Meeting, and that council is looking to have a document stating Council have the 7 reports which lists options on improving and mitigating flooding for Councils investigation and how Council is progressing. It was noted that this document will be brought back to the Committee for review.

Meeting Closed 4:05pm – Clr Howard

Flood Management Advisory Committee Meeting

24 July 2024

Item No: FMACC0724(1) Item 1

Subject: Outstanding Actions Register

Prepared By: David Paton - Engineering Services Manager

Authorised By: Ryann Midei - Director Infrastructure

RECOMMENDATION

That the Outstanding Actions Register be received and noted.

OUTSTANDING ACTIONS REGISTER

The following table provides the status of outstanding actions from previous Flood Management Advisory Committee meetings.

Meeting	Item	Actions	Comments	Status
29/2/24	4.1	That the Flood Management Advisory Committee endorse the updated Terms of Reference subject to replacing Transport for NSW Roads with Transport for NSW.	The Terms of Reference were adopted by Council at its meeting on 9 April 2024	Completed
29/2/24	5.1	That the Flood Management Advisory Committee support the schedule of actions to be taken to facilitate flood education within Inner West Council.	Noted	No action required
29/2/24	5.2	That Council develop communications regarding flooding and relevant services in the local area including the SES that can be made available through customer service centres, libraries and be made available to local real estate or rental agencies for new residents to the local community	An update will be provided at the next Committee meeting	In Progress
29/2/24	5.3	That Council better support and promote the activities of the SES, including in our local newsletter.	An update will be provided at the next Committee meeting	In Progress
29/2/24	5.4	That in the development of the Flood Information Hub, Council work to make emergency information for accessible and visible, that Council investigates the reporting of local road closure information.	An update will be provided at the next Committee meeting	In Progress
29/2/24	5.5	That the proposed information sessions undertaken with the Alexandra Canal Flood Risk Management Study and Plan and Johnstons Creek Whites Creek Flood Risk Management Study and Plan be undertaken with SES Officers.	SES Officers participated in the four information sessions during the exhibition period.	Completed
29/2/24	5.6	That Council investigate the publication of evacuation routes among consideration of public signage.	An update will be provided at the next Committee meeting	In Progress
29/2/24	5.7	That Council engage directly with community groups on the foreshore impacted by flooding.	An update will be provided at the next Committee meeting	In Progress
29/2/24	7.1	That the Flood Management Advisory Committee endorse the public exhibition of the Alexandra Canal Flood Risk Management Study and Plan.	Council resolved to exhibit the Study and Plan at its meeting on 9 April 2024. Exhibition is now complete, with its outcomes being tabled at July committee meeting	Completed
29/2/24	7.2	That the Flood Management Advisory Committee endorse the public exhibition of the Johnstons Creek and Whites Creek Flood Risk Management Study and Plan	Council resolved to exhibit the Study and Plan at its meeting on 9 April 2024. Exhibition is now complete, with its outcomes being tabled at July committee meeting	Completed

ATTACHMENTS

Nil.

Flood Management Advisory Committee Meeting

24 July 2024

Item No: FMACC0724(1) Item 2

Subject: Flood Mitigation and Upcoming Projects

Prepared By: David Paton - Engineering Services Manager

Authorised By: Ryann Midei - Director Infrastructure

RECOMMENDATION

The Flood Management Advisory Committee receive and note this report.

STRATEGIC OBJECTIVE

This report supports the following strategic directions contained within Council’s Community Strategic Plan:

1: An ecologically sustainable Inner West

5: Progressive, responsive and effective civic leadership

EXECUTIVE SUMMARY

Council have adopted four Flood Risk Management Study and Plans to date, with an additional two to be reported to Council for adoption in September 2024. These Flood Risk Management Study and Plans outline proposed flood mitigation options across the Local Government Area in order of priority or in accordance with cost benefit throughout their relevant catchments.

Council have implemented a number of flood mitigation actions across the Local Government Area, including:

· A review of structural mitigation options identified in Flood Risk Management Studies and Plans

· A grant application for the Marrickville South Flood Study,

· Progressed grant funded flood mitigation designs at Lord Street Newtown and three other locations in Marrickville and Newtown,

· Responded to a significant flood event in April 2024, and

· CCTV inspections, cleaning and maintenance to stormwater assets.

BACKGROUND

At the Flood Management Advisory Committee Meeting held on the 29 February 2024, the Flood Management Advisory Committee was advised that an update on flood mitigation programming would be brought to the Committee for review.

DISCUSSION

Flood Mitigation Programming

Council have adopted four Flood Risk Management Study and Plans to date, with an additional two to be reported to Council for adoption in September 2024. These include:

Adopted

1. Eastern Channel Subcatchment Management Plan (Golder Associates, 2011)

2. Marrickville Valley Flood Risk Management Study and Plan (Cardno,2017)

3. Leichardt Flood Risk Management Study & Plan (Cardno, 2017)

4. Dobroyd Canal and Hawthorne Canal Flood Risk Management Study and Plan (WMA, 2019)

To be adopted

5. Alexandra Canal Flood Risk Management Study and Plan (Stantec, 2024)

6. Whites Creek and Johnstons Creek Flood Risk Management Study and Plan (Stantec, 2024).

The studies and plans provide a list of flood mitigation options covering almost 90% of the Local Government Area, including recommendations for structural management options, such as stormwater drainage upgrades which have been ranked in order of priority or in accordance with cost and benefit.

Catchment	Infrastructure Upgrade Options (Total number/cost)	Costs/ Prioritisation
Eastern Channel Subcatchment	10/ $16 million	Estimated project costs range from $76,000 to $3.6 million
Marrickville Valley	32/ $35 million	9 projects are listed as high priority, 11 as medium and 12 as low
Leichardt (whole of former LGA)	36/ $250 million	The recommended projects are prioritised and categorised in their respective sub-catchments
Dobroyd Canal and Hawthorne Canal	6/ $20 million	3 projects are listed as high priority, 2 as medium and 2 as low
Alexandra Canal	4/ $5 million	One project is listed as high priority, 2 as medium and 1 as low
Whites Creek and Johnstons Creek	12/ $15 million	4 projects are listed as high priority, 6 as medium and 2 as low

Although the studies and plans do not provide a prescribed schedule for implementation, they identify the mitigation measures that have merit for implementation as funding becomes available or when opportunity arises for Council to seek funding and support through NSW government including the Department of Planning and Environment. These plans provide a sound basis from which Council can make decisions concerning the undertaking of works, planning decisions, and developing response arrangements to reduce the impact of flooding.

Notwithstanding the above, a further analysis of the mitigation options will be undertaken to assist with the comparative prioritisation between individual options across the various catchments and help formulate the annual Capital Works programs and balance community expectations.

A report will be prepared for the next Committee meeting to present the outcomes of this analysis.

Marrickville South Flood Study

Council has applied to the Department of Planning and Environment under the Floodplain Management Program for funding for the Marrickville South Flood Study in early May 2024. This is the final catchment area within Inner West Council Local Government Area that has not had a comprehensive catchment-based modelled flood study.

The study area is approximately 200 hectares and encompasses areas draining directly to the Cooks River, including parts of the suburbs of Marrickville and Dulwich Hill, and is bounded by the Cooks River in the south, Garnett Avenue to the west and New Canterbury Road to the north.

The catchment is fully urbanised and susceptible to localised flash flooding. Low lying areas along the Cooks River are particularly susceptible to overland flooding during high tides or river flood event. The age of the area means that there are also many trapped low points which are particularly susceptible to flooding.

The flood study will provide updated 2D flood depth modelling with TUFLOW, and more comprehensive identification of flood affected lots within this area. Characterisation of flood behavior and an identification of flood affected properties within the area will support better targeting of planning controls and facilitate future Flood Risk Management Planning.

Previous studies were limited to localised 1D studies of parts of the area (approximately 60% of proposed study area), undertaken in 2000 and 2009 and identifying 106 properties affected by flooding in the 1% Annual Exceedance Probability event.

The project is anticipated to be commenced during the 2024/25 financial year after a decision on the funding application (a condition of the grant application), which is anticipated in the coming months.

Lord Street Design Update

The Lord Street Drainage Upgrade project was identified as a high priority project in the Eastern Channel East Subcatchment Flood Risk Management Study and Plan, listed for the 2020/21 Stormwater Capital Works Upgrade Program for design.

The initial scoping consisted of stormwater pit and pipe upgrades and extensions through John Street, Wells Street, Pearl Street, Edgeware Road and Lords Street, Enmore and a consultant, Warren Smith Partners (WSP) were engaged by Council to undertake this design concept.

There have been a number of challenges during this design process and as a result the original project scope has evolved. WSP commenced borehole and pothole investigations to accurately identify underground services, and as a result several have been detected in the project area, including Transgrid high voltage transmission lines, Ausgrid lines and high-pressure Jemena Gas lines.

The main difficulty has been to design stormwater pipes that have safe clearance from existing services, hence reducing not only construction costs but risk to life during the construction phase of this project.

Design Grant Funding

Council has successfully obtained funding from the Department of Planning and Environment in January 2024, totalling $231,392 under the Flood Recovery and Resilience Grant program.

The grant fund is for 75% of proposed design work and requires a 25% Council co-contribution of $107,983.25, with a total project cost of $339,375.25 for the following projects:

1. Illawarra Rd, Marrickville - Increase stormwater inlet capacity along Illawarra Rd, York and Shephard Streets, Marrickville. This project is from the Marrickville Valley Flood Risk Management Plan and is listed as high priority.

2. Addison Road, Marrickville - Installation of new inlet pits and 600mm diameter pipes along England Avenue, Agar Street and Wemyss Street, Marrickville. This project is from the Marrickville Valley Flood Risk Management Plan and is listed as high priority.

3. Edgeware Rd, Newtown New pit/pipe along Edgeware Rd from Sarah St to Camden Street. New Pit/pipe at the corner of Lynch Avenue and Edgeware Rd. This project is from the Eastern Channel Subcatchment Management Plan and listed as fourth in regard to economic ranking.

These designs are currently under way and are anticipated to be completed by June 2025. Council will need to apply again for funding from Department of Planning and Environment for the delivery of these works.

April 2024 Flood Response

The rainfall events in April 2024 occurred in short intense bursts, with 6th April having the highest rainfall for the month at 167mm, measured at the Marrickville Golf Club. This resulted in Council receiving a total of forty-nine requests from residents across the LGA. Council staff arranged times, convenient to the residents and met most of them (dependent on resident availability) on site to better understand their concerns and action accordingly.

As a result of these site meetings and subsequent investigations, the following projects were scoped and brought forward into Council’s 2024/25 Stormwater Capital Works Program for design, with delivery in 2025/26:

1. Roseberry Street, Balmain

2. Ramsay Street and Bland Street, Haberfield

3. Palace Street and Holden Street, Ashfield

4. Pyrmont Street, Queen Street and Robert Street, Ashfield

5. Malakoff Street, Marrickville

6. Piggott Street, Dulwich Hill

In addition, minor modifications will be made to the local drainage systems at these locations as part of the 2024/25 Stormwater Capital Works Program to improve the existing systems and optimize capacity.

Hawthorne Parade, Haberfield was also identified as requiring stormwater upgrade works during this process. In addition to stormwater pit and pipe upgrades, this location will also require upgrade to multiple elements, including kerb and gutter and road re-sheeting, estimated at more than $1 million. These works are currently being considered for construction on a staged basis from 2026/27, with design to take place in 2025/26.

Flooding also occurred in the streets around Northcote Street Marrickville, which already has stormwater upgrade works programmed for 2024/25.

Stormwater Asset Maintenance

Stormwater asset maintenance can be described as actions that are undertaken either on a day-to-day basis necessary to meet levels of service delivery requirements and can include clearing debris from stormwater pits and pipes and proactive and reactive inspections, undertaken by in-house technical staff and/or specialist contractors. These activities do not improve the condition of the assets; however, they provide relief by removing blockages within the stormwater network or assisting with investigative works for future planning.

In the 2023/24 financial year Council have spent a total of $183,742.29 on stormwater CCTV inspections and $243,587.17 on stormwater pit and pipe cleaning, covering 18 kilometres or close to 10% of Councils stormwater network. Locations are most often actioned based on reactive responses or resident requests.

Dependent on the findings of these inspections, they can form the basis for projects being added to future Councils Stormwater Capital Works Program, for renewal and/or upgrade. Otherwise, they may result in minor maintenance or upgrade works by Council’s Civil Works Team, such as new pits or reconstruction of inlet pits.

FINANCIAL IMPLICATIONS

There are no financial implications associated with the implementation of the proposed recommendations outlined in the report.

ATTACHMENTS

Nil.

Flood Management Advisory Committee Meeting

24 July 2024

Item No: FMACC0724(1) Item 3

Subject: Outcomes of the exhibition of the final Alexandra Canal Flood Risk Management Study and Plan and Whites Creek and Johnstons Creek Flood Risk Management Study and Plan

Prepared By: David Paton - Engineering Services Manager

Authorised By: Ryann Midei - Director Infrastructure

RECOMMENDATION

That the Flood Management Advisory Committee note the outcomes of the exhibition of the final draft Alexandra Canal Flood Risk Management Study and Plan and Whites Creek and Johnstons Creek Flood Risk Management Study and Plan and endorse them to be tabled at Council.

STRATEGIC OBJECTIVE

This report supports the following strategic directions contained within Council’s Community Strategic Plan:

1: An ecologically sustainable Inner West

5: Progressive, responsive and effective civic leadership

EXECUTIVE SUMMARY

The draft Alexandra Canal Flood Risk Management Study and Plan and draft Whites Creek and Johnstons Creek Flood Risk Management Study and Plan was placed on public exhibition for five weeks from the 4 June to the 12 July 2024.

This report discusses the outcomes of the community engagement held for the Alexandra Canal Flood Risk Management Study and Plan and the Whites Creek and Johnstons Creek Flood Risk Management Study and Plan and seeks the endorsement of both documents for adoption by Council.

BACKGROUND

At the Council meeting held on 9 April 2024, Council resolved the following in part:

3. That Council publicly exhibit the draft Alexandra Canal Flood Risk Management Study and Plan for a period of 28 days and seek community feedback on it.

4. That Council publicly exhibit the draft Whites Creek and Johnstons Creek Flood Risk Management Study and Plan for a period of 28 days and seek community feedback on it.

5. That following the conclusion of the exhibition period, the draft Alexandra Canal Flood Risk Management Study and Plan and the Whites Creek and Johnstons Creek Flood Risk Management Study and Plan be brought back to Council for consideration for adoption.

Council has completed five Flood Risk Management Study and Plans across eight of its catchments, covering almost 80% of the Local Government Area (LGA). After adoption of the Alexandra Canal Flood Risk Management Study and Plan and the Whites Creek and Johnstons Creek Flood Risk Management Study and Plan, 90% of the LGA will have been completed.

The Alexandra Canal Flood Risk Management Study and Plan and Whites Creek and Johnstons Creek Flood Risk Management Study and Plan have been developed by Council Engineers, representatives from the NSW Department of Climate Change, Energy, the Environment and Water, and specialist flood modelling consultants Stantec.

The studies include a comprehensive review of the existing flood models for these catchments and further modelling to assess the impacts of possible upgrade measures to reduce flooding across the catchments.

An initial count of 40 possible flood mitigation works, including pipe upgrades, road modifications, detention basins and pit improvements were assessed for overall impact and improvement to flood risk in the community, in conjunction with 6 options for Council-led property modification and 6 options for emergency management improvements.

The assessment resulted in a shortlist of six mitigation options for Alexandra Canal, 13 mitigation options for Whites Creek and Johnstons Creek, and five property and emergency management measures for both studies.

The Whites Creek and Johnstons Creek FRMSP reviews 20 options and considers seven options to have a high implementation priority including:

- Drainage Upgrade at Probert Street ($500,000)

- Detention Basin at Bridge Road ($1.4 million)

- Drainage Upgrade at Lennox Street ($2.3 million)

- Drainage Upgrade at Gladstone Street ($1.6 million)

- Data Coordination with NSW SES

- Community Flood Awareness Strategies

- Implementation of Flood Markers & Signage

The Alexandra Canal FRMSP reviews nine options and considers four options to have a high implementation priority including:

- Drainage Upgrade at Bay Street ($1.1 million)

- Data Coordination with NSW SES

- Community Flood Awareness Strategies

- Implementation of Flood Markers & Signage

Of the non-capital options – i.e., Data Coordination, Community Flood Awareness, and Flood Markers, Council Engineers will continue to work with NSW SES to further develop and implement these strategies. Data Coordination takes place as part of the overall handover of materials following completion of a Flood Risk Management Study and provides NSW SES with flood depths, response times, isolated areas, and road cutoffs to inform their decision-making.

Beyond capital works upgrades, the reports also provide a review of current planning controls, and a review of Emergency Management information, including response times, isolated areas, and road cutoffs to inform their decision making and planning.

The Final Flood Risk Management Studies and Plans are included as attachments to this report.

DISCUSSION

Community engagement is identified in the NSW Flood Risk Management Manual as an integral part of the flood risk management process as it raises awareness and can provide base information for further community flood awareness activities.

The draft Alexandra Canal Flood Risk Management Study and Plan and the Whites Creek and Johnstons Creek Flood Risk Management Study and Plan was placed on public exhibition for a period of five weeks from the 4 June to 12 July 2024.The exhibition was coordinated through Council’s Your Say Inner West community engagement page and letters of notification were also extended to owners of properties identified as Flood Affected Properties.

During the public exhibition period, the community members, SES and interested parties were invited to review the study and plan, submit comments, and indicate the extent of their support for the study, plan and its outcomes. Community members were also able to provide comment on which options they support, which options they do not support, and any matters related to flood mitigations and management that had not been addressed in the study and plan.

Four community workshops were held during the public exhibition period to present the findings of the study and plan and sought input from the community. The workshops were held at Marrickville SES on 13 June and 20 June 2024 and at Marrickville Library, The Pavilion on 24 June and 2 July 2024. Draft documents and printed flood mitigation options maps were also displayed as part of the exhibition.

Public Exhibition Response Statistics

Across the public exhibition period there were 23 recorded responses across both Alexandra Canal FRMSP and Whites Creek and Johnstons Creek FRMSP through one of four response methods:

· Phone calls to Council by 4 different respondents in relation to the public exhibition of the study.

· Your Say comment uploads (3 participants) and Your Say questionnaire responses (1 participant) by 4 total participants.

· Email responses submitted to Council by 4 respondents.

· 11 in-person attendees at the information sessions. These attendees consisted of 1 at the first session, 2 at the second, 7 at the third, and 1 at the fourth session.

Across all response methods, 1 comment (Your Say upload) related to Alexandra Canal FRMSP. All other responses were related to Whites Creek and Johnstons Creek catchment areas.

Although this represents a total of 23 engagements, it should be noted a number of households made several engagements for some households, most commonly residents attending in-person sessions often completed another form of response such as a Your Say written response or email.

With respect to Your Say outcomes from the public exhibition period, there were a total of 708 visits across both Alexandra Canal FRMSP and Whites Creek and Johnstons Creek FRMSP project pages. 459 of these visits were for Whites Creek and Johnstons Creek FRMSP, with 68 downloads, and 249 were for Alexandra Canal FRMSP, with no downloads.

During the public exhibition period, Council provided stakeholders with the draft final FRMSP report. As part of this engagement;

One comment was received from Sydney Water regarding the number of overfloor flooded buildings reported. A clarifying response was provided to Council via an email, to be passed onto Sydney Water.

Council’s Strategic Planning team commented on the report. Clarifying responses were provided to Council via an email, and updates to the report were made where necessary.

Whites Creek and Johnston Creek – Summary of Comments from the Public

The most common concerns received across the various forms related to the following:

· Localised stormwater issues not within the scope of flood risk, i.e. maintenance or drainage issues to be addressed by means of temporary solutions prior to the implementation of mitigation options or otherwise captured under Council’s capital works

· General enquiries either outside of the catchment subject areas or requesting information about the FRSMP and the proposed mitigation options.

Specifically relating to the flood risk management options, the following comments were received during public exhibition:

· A concern was raised about flooding in the junction of Gladstone Street and Phillip Street in Enmore. The attendee communicated that the flooding was caused by insufficient drainage on King Street. There is a valid flood risk concern to properties further downstream of this intersection, which are subject to low flood island effects. These properties have been assessed to benefit from Option JC13. However, at the intersection where the concern was raised, the observed H5 hazard category within a 1% AEP event is contained within the road corridor. It is also understood that the further upstream King Street is a TfNSW owned asset. Due to these factors affecting feasibility comparative to flood risk benefits, it is unlikely for further proposed solutions in this location to be scored favourably in terms of CBR and MCA.

· A concern was raised about flooding to a property on Salisbury Road, Camperdown near Church Street in the Johnstons Creek catchment. There is a valid flood risk concern to these properties due to the trapped low point with H4-H5 hazard category of flooding within a 1% AEP event. No solution was proposed during option development due to high level feasibility issues resulting from the limited diameter of downstream pipes. It is noted that the subject pits are part of Council’s capital works program, and that Council is currently progressing longer term feasibility assessments as part of a separate study. In the meantime, Council may implement an interim approach to mitigate flooding in the short-term including investigating the inlet capacity at that location.

· A concern was raised about Salisbury Lane, Stanmore near the inlets to the Johnstons Creek stormwater channel. The attendee provided images showing flooding of the street, caused by the invert levels of the inlet pipes sitting above the existing street surface level. The subject location is mostly H2 hazard, with minor spots of H3-H4 within a 1% AEP event. The feedback provided by the attendee merits public safety concerns, and it is understood that Council will investigate inlet capacity or drainage upgrades in this area separate from the FRMSP and as part of their capital works.

· Two concerns were raised regarding flood risk classification, insurance premiums and property values in the Johnstons Creek catchment. The community members for these areas did not consider their property to be flood affected. The Flood Study model has been reviewed as part of the FRMSP, and the assumptions used were found to be generally reasonable in line with industry best practice and guidelines. It is noted that these types of concerns relate to the previous Flood Study process where flood affectation of properties was assessed, whereas the focus of the FRMS&P engagement was on the proposed flood risk management options. On Australia Street, there is a proposed JC20 drainage upgrade option directly benefiting the affected properties in this subject area, which are subject to H4 hazard category of flooding within a 1% AEP event.

· A concern was raised regarding Corunna Street in the Whites Creek catchment. The attendee suggested the installation of raingardens additional to the proposed WC1 drainage upgrade option. The option types (i.e. drainage upgrade, road regrading, detention basin, etc) were developed with consideration of feasibility, cost and likelihood of scoring favourably in terms of CBR and MCA. The introduction of a raingarden, though may slow flows and improve water quality treatment in higher frequency events, is not likely to cause reductions to flooding downstream in larger rare events such as the 1% AEP. Council may wish to consider the benefits of installing raingardens as part of a separate feasibility study or included within the capital works program.

Alexandra Canal – Summary of Comments from the Public

The concerns received across the various forms related to the following:

· General enquiries either outside of the catchment subject areas or requesting information about the FRSMP and the proposed mitigation options.

· The only response related to Alexandra Canal FRMSP via upload to Your Say, generally supporting the measures outlined in the report. The response highlights the 2017 Cooks River Flood Study and recommends an overall LGA wide list of prioritised projects for residents. Council is considering consolidation of a list of the flood risk management options across the LGA to present to FRMAC.

Outcome of Consultation

The consultation process was well received, with strong engagement achieved through the Your Say webpages, combined with moderate attendance at the information sessions and other modes of communication.

Overall, the submissions received were supportive of the two draft Studies and Plans. Where concerns were raised, the reports have been updated to summarise them, and provide an explanation of how they were answered or will be addressed, as above.

The two final draft reports are attached to this report and are recommended for endorsement.

FINANCIAL IMPLICATIONS

The Alexandra Canal draft report recommends four infrastructure upgrade projects at a total cost to Council of $5 million.

The Whites Creek and Johnstons Creek draft report recommends twelve infrastructure upgrade projects at a total of $15 million.

These projects will be progressively incorporated into the future works program on a priority basis, and as opportunity and funding are available.

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